FISH-GAME California Fish and Game is a journal devoted to the conserva- tion of wildlife. Its contents may be reproduced elsewhere pro- vided credit is given the authors and the California Department of Fish and Game. The free mailing list is limited by budgetary considerations to persons who can make professional use of the material and to libraries, scientific institutions, and conservation agencies. Indi- viduals must state their affiliation and position when submitting their applications. Subscriptions must be renewed annually by returning the postcard enclosed with each October issue. Sub- scribers are asked to report changes in address without delay. Please direct correspondence to: LEO SHAPOVALOV, Editor Department of Fish and Game 926 J Street Sacramento 14, California Individuals and organizations who do not qualify for the free mailing list may subscribe at a rate of $2 per year or obtain indi- vidual issues for $0.75 per copy by placing their orders with the Printing Division, Documents Section, Sacramento 14, California. Money orders or checks should be made out to Printing Division, Documents Section. 1 J D VOLUME 42 JANUARY, 1956 NUMBER 1 Published Quarterly by the CALIFORNIA DEPARTMENT OF FISH AND GAME SACRAMENTO STATE OF CALIFORNIA DEPARTMENT OF FISH AND GAME GOODWIN j. KNIGHT Governor FISH AND GAME COMMISSION WILLIAM j. SILVA, President Modesto ANDY KELLY, Commissioner L°s Angeles CARL F WENTE, Commissioner HARLEY E KNOX rnm ■ • Sa" Francisc° t- ^UA, Commissioner wcmA., , Son Diego WELDON L. OXLEY, Commissioner Redding SETH GORDON Director of Fish and Game CALIFORNIA FISH AND GAME » SHAPOVALOV, Editor-in-Chief ^^ ^ JOHN E. FITCH, Editor for Morine Fisheries Socromento CAROL M. FERREL, Editor for Gome Terminal Islana 1 B KIMSEY, Editor for ln|and Fisheries Sacramento Sacramento TABLE OF CONTENTS Page Chronic Toxicity of DDT. Toxaphene, and Dieldrin to Ring-necked Pheasants Richard E. Genelly and Robert /,. Rudd 5 Characteristics of the Pelvic Girdle in Relation to Sex in Black- tailed and White-tailed Deer Richard I). Taber 15 Progress Reporl on White Sturgeon Studies Richard L. Pycha 23 Further Observations on Stream Survival of King Salmon Spawn Harold A. Gangmark and Robert I). Broad 87 An Ecological study of Lower San Gabriel River, California, With Special Reference to Pollution- Donald ■/. Reish 51 A New .Method of Attaching Petersen Disk Tags With Monofila- '.— incut Nylon John E. Randall 63 Rearing Larval Scombrid Pishes in Shipboard Aquaria Harold 11. Clemens 69 X( )TE Blue-winged Teal in Del Norte County. California Charles F. Yocom and William A. Wooten 81 Reviews 83 (3) CHRONIC TOXICITY OF DDT, TOXAPHENE, AND DIELDRIN TO RING-NECKED PHEASANTS' RICHARD E. GENELLY and ROBERT L. RUDD Department of Zoology University of California, Davis INTRODUCTION The use of highly toxic chemicals to control agricultural insect pests is widely accepted. However, reports of the finding of dead animals in chemically-treated areas continue to command attention. Thai the chemicals caused the death of the animals is difficull or impossible to establish in most cases (l)ahlen and Haugen, 1954), but the evidence is strong enough to warrant intensive investigation (Mohr e1 al., 1952; Knild and Genelly, 1955). Of first importance to such an investigation is a knowledge of the toxicity of each chemical agent to the principal wildlife species that might be exposed. Wildlife populations could con- ceivably be affected in two ways: outright killing of individual animals by single or multiple exposures to the chemical; or, a decline in the reproductive rate of the population. The effects of DDT. toxaphene, and diehlrin on pheasant reproduc- tion will be reported in another paper i Genelly, R. E., and K. L. Rudd, MS). The present paper reports on the responses of 224 adult ring- necked pheasants (Phasianus colchicus) to daily intake of small amounts of three chlorinated hydrocarbon insecticides for periods ranging up to 94 days. Experimental feeding of DDT. toxaphene, and dieldrin to 121 female pheasants began in the fall of 1953 ("Prerepro- ductive period". Table 1> at the Yountville state Game Farm, near Yoini! ville. California. At the conclusion of this test, in February, 1954, 90 additional females and nine male pheasants were started mi selected chemical levels (Tables 1 and 2) and maintained on them for two and one-half months of the breeding season ("Reproductive period", Table 1). (Mortality of males necessitated the addition of four birds during the experimental period.) EXPERIMENTAL CONDITIONS In the "prereproductive" feeding tests. 130 previously uneontami- nated six-month-old female ring-necked pheasants were divided among 12 holding pens leach 12 by 20 feet i. A group of 10 birds was main- tained as a control. All birds were weighed at the beginning of the test Submitted for publication May, 1955. The authors are indebted to a number of pei sens Eor assistance: personnel of the State Game Farm a1 STountville, especially Frank James, Cor care and maintenance of the pheasants ; Dr. S. Anderson Peoples and H. Edward Bond, of the School of Veterinary Medicine, University of Cali- fornia, for the chemical analyses of pheasant tissue : ana K. c. Carlson of the Uni- versity Cnsectary, for the use of seed treatment equipment. This study was carried on under Federal Aid in Wildlife Restoration Act, Projecl California W-45-R, "Thi Effects of Economic Poisons on Wildlife." I •"» ) 2 25467 I « Al.llciKM \ PISH AND i. \Mi: period and at infrequent intervals thereafter Figure 1). During or at tli inclusion of tin- experiment one bird at each chemical level was sacrificed for histopathologica] study (Table 3). No attempl was made to analyze these samples for the presence of the chemical. The birds were maintained entirely <>n a diet of "hen scratch" IVcd, which is 70 percenl wheal and 30 percent a mixture of cracked corn, milo, kaffir, and hulled barley. The feed was contaminated with desired levels of chemicals by thoroughly agitating 50-pound lots of chemical and feed in an electric mixer. In the "reproductive" feeding tests, previously ancontaminated pheasants were used 1 male and 10 females in cadi of 12 Large breeding pens. Three of these groups of birds were kept as controls. The insecticide was mixed thoroughly with a high-protein (21 percent) diet of commercial turkey \'<\ in pellet form. Since a measured amount of scratch grain was substituted when rainy weather threatened pellet disintegration, the concentration of the chemical in the "total diet': was Lower than the concentration to which the birds were usually exposed (Table 2). To minimize handling, birds were weighed only at the beginning and end of the experiment. Tissue samples of females, for chemical analysis and histological study, were obtained from birds sacrificed at the end of the study (day number 74). Tissues from sev- eral males that succumbed during the test period were analyzed for presence of the chemical (Table '■]). TABLE 1 Pheasant Mortality From Insecticide-contaminated Diets Prereproduetive period Reproductive period < chemical P.p. 1,1. iti diet No. of birds 9 9 Test pei lo 1. da j Mor- talitj 9 9 No. of test birds Tesl period, days Mortality & & 9 9 0*0" 9 9 DDT :,ii 100 200 400 600 1(1 10 111 10 57 90 90 57 0 1 0 3 1 4 10 20 74 74 0 4 0 0 1 25 Kill 200 300 10 10 10 10 51 94 94 '.M 0 0 0 0 1 2 10 20 74 74 0 0 0 0 1 (ieldi in 25 .-,11 TO [00 L'OII 1 1 10 10 1(1 49 20 38 28 0 2 5 (i 1 4 III I'll 74 71 1 4 0 8 < lontrol 10 91 0 4 30 74 0 0 TOXICITY OF INSECTICIDES TO PHEASANTS 7 TABLE 2 Food Consumption, Insecticide Intake, and Weight Changes of Pheasants During the Reproductive Period ( chemical ( loncenl ration ol chemical p. p.m. Mean daily comsumption bird daj Mean In e weight changi In mash lu total die! Mash, l'im. ( Ihemical, nm. of females (crams) DDT - 100 Hill 100 300 25 50 ii 00 355 89 243 12 (I .".7 . 2 52 1 47.4 30.4 14.6 36.6 51 .6 5 7 J 20.84 4.74 9.12 1.12 1 83 0.0 + 20 DDT —22 + 9 —62 Dieldrin - 1 lieldrin 14 36 ( lontrol - 64 EXPERIMENTAL RESULTS Mortality In the prereproductive period the deaths of only four birds could be assigned to the toxic effect of DDT at the four levels fed. One bird was observed to exhibit severe tremors the day before it died. The others may have too, but a close daily watch was not kept over the birds. All were found after death with legs rigidly extended, a position char- acteristic of poisoned birds. All birds on toxaphene contaminated diets survived, although at the highest level several became relatively inac- tive, appearing to be in serious condition. In other studies, chickens on a diet containing '200 p. p.m. (parts per million) of DDT survived for a year without toxic symptoms (Bryson et al., 1950), while 90 percent of laying hens on a diet containing 1,250 p. p.m. died within 12 weeks (Rubin et al.. 1947). All New Hampshire chicks exposed to 50-100 p. p.m. of dieldrin in the diet died in 90 days (Eden. 1951). Feeding dieldrin. begun in midwinter, produced quick mortality at levels of 70 p. p. m. and higher. At 70 p. p.m. two birds had died by the 19th day; at 200 p. p.m. six birds had succumbed by the 26th day. and the remaining four were behaving erratically; at 100 p. p.m. five of the females had died by the :;sth day. Mortality was so severe at the loo and 200 p.p.m. levels that poison was discontinued after the days men- tioned above. Only the birds on 25 p.p.m. appeared to be unaffected and remained so through day 49. Meanwhile, the 10 "control" pheas- ants, in an adjoining pen. continued to appear normal. All of the birds were removed from the test diets by mid-February. The feeding tests of the reproductive period were under way by March ls|. During the ensuing 71 days the females showed no signs of distress from either DDT or toxaphene. The females on 50 p.p.m. of dieldrin. however, suddenly began to die on the 60th day. Eighl of t hem were dead by the final day (number 74). Again, there was little doubt that death was due to the chemical. Males were definitely more susceptible to DDT and to dieldrin than were females. One male exposed to 50 p.p.m. of dieldrin suddenly died on day number 28; a replacement died 15 days later; a second replace- ment succumbed after only six additional days. The original male receiving 50 p.p.m. of dieldrin in another pen died on the 48th day 8 lUFOBN] \ PISH \\l> GAME and was in>t replaced. The original male receiving 25 p. p.m. of dieldrin died on day number 59; similarly, one male exposed to too p. p.m. of DDT died after 42 days. A second cock ;it this level died after 57 days of exposure. His replacemenl died after onlj one day in the pen, but probably qoI t ause of the chemical. The difference in the sexes in susceptibility to DDT support earlier observations on experi iii.il feeding of DDT-coated seed rice to pheas- ants i WihM and (ienelly, 1!)55). Under similar conditions of exposure, four of six males died, while only one of six females died. Weight Changes Bodj weighl changes of pheasants during the prereproductive tests were carefully followed ;is possible indicators of pheasant condition. The patterns of these mean weight changes varied between groups ex- posed t<> different chemicals and were not always clearly related to the degree of intoxication of the birds. In Figure, 1, the beginning mean weights of all experimental groups are arbitrarily given a com- mon beginning point. Subsequent mean weight deviations from the original means are then plotted as percentage of body weight. Indi- \ idnal wcighl variations within each group were of sufficient magnitude to render meaningless any statistical tests of significance. DDT, even at the highest levels, seemed to have Little effect on the mean weights of the groups. Indeed, these experimental birds weighed more than the control birds for most of the experimental period I Figure 1). Toxaphene, however, had a depressing effect on body weight, at least for the first month of the period -apparently because the birds disliked the contaminated feed. Checks during the breeding season (Table 2) showed that birds fed the highest levels of toxa- phene probably ate only GO percent as much food as did the control birds. Bui at the end of three months they seemed to have adapted to the diet, for the mean weights again approached that of the control group. The heavy mortality among birds consuming 100 and 200 p. p.m. of dieldrin, mentioned earlier, was accompanied by rapid weight loss. The pheasants on 25 and 70 p. p.m., however, differed little from the controls in weight changes. The spring studies also showed that mean food consumption went down as concentration of insecticide in the diet went up. Moreover, the net weight changes of the females during the 74-day spring test period appeared to reflect their average degree of intoxication at each level of each chemical (Table 2). However, it is obvious from the weight fluctuations of the control birds (Figure 1 thai no hard and fast rules on pheasant condition can be based on weight change alone. Tissue Analysis Tissue samples for chemical analysis and histological study were taken only during the reproductive period. With three exceptions (Table 3), all of these samples were from hints sacrificed on the 74th day. 'tissue samples For study, taken within 15 minutes of the death id' the birds and placed in Bouin's fixative, were later sectioned at eight miera. mounted on vdass slides, and stained with Harris' liemo- toxylin and eosin, and with Ileidenhain's "azan" triple stain. Samples for chemical analysis were preserved by freezing. These tissues were TOXICITY OF I.YSKI TIC1DKS TO FTIFASA NTS DAY OF EXPERIMENT 30 40 50 60 70 o < o ir UJ LiJ o < X o X UJ t 1 1 1 1 1 1 1 r 10 20 30 40 50 60 70 80 90 DAY OF EXPERIMENT FIGURE 1. Weight changes during test period in experimental feeding of DDT, toxaphene, and dieldrin. 10 I ai.IImkma PISH \M> GAME later pulverized in the laboratory, and extracted with benzine. After evaporation of the benzene, the material was submitted to reduction with metallic sodium and analyzed for organic chloride content by a modification of the amperometric titration method of Eolthoff and Lingane L952 . Tissues from control birds were used to determine normal organic chloride contenl and standard recovery rate. These values were used in computing the insecticide concentrations listed in Table 3. TABLE 3 Chemical Analyses and Tissue Studies < 'oncen- i ration in total diet (p.p Bird no. - 1 peri- mental period in daj - Tissue ( Concen- tration Of I'Ih in ical in tissue (p.p.m.) Histological findings DDT 90 190 9 71 Liver 0.0 Moderate fatly change; focal damage; margination of cytoplasmic granules; some nuclear necrosis. 1 in 1,095.0 N. E. (Not examined i 90 789 cT 74 Liver 1 . 55* Light vacuolation; some peripheral granulation. Testis 0.0 seemingly normal. :s.-..j I?:. 9 74 Liver L46.0 Extreme fatty change; sinusoids en- gorged; swollen nuclei; focal damage in streaks radiating from major ves- sel. Fat 3,460.0 N. E. 181 9 74 Liver 16.0 Light vacuolation only apparent effect. \ Fat 4,470.0 N. E. 790 & 42 l.l\ IT 52.0 N. E. Testis 1,290.0 N.E . TOX- APHENE 89 168 9 74 l.n i'i 0.0 Sinusoids engorged throughout liver; cells seem normal. 1 at 292.0 N. E. 89 792 & 74 Liver 0.0 Moderate vacuolation. Testis 1,510.0 Zoa in lumen; mitotic figures. 90 9 71 l.l\ IT 6.1 Little effect; some vacuolation around major vessels. 24 : 794 c? 71 Liver 0.0 Heavy vacuolation, entire surface; no foci. Testis 0.0 Zoa in lumen; mitotic figures. 157 9 71 Liver 1.6 Little affected; some vacuolation about major vessels. 1 Ml 7.", 2 it N.E. TOXICITY OF [NSECTICIDF.S To I'HKASAXTS 11 TABLE 3— Continued Chemical Analyses and Tissue Studies ( 'ill tration in total diet (p.p.m.) Bird no. Sex Expei i mental period in days Tissue i !oncen- i ration of chem- ical in 1 1- sue (p.p.m.) Histological findings DIEL- DRIN 22 88 9 71 Liver 0.0 Light \ acuolation about none peripherally. Fat 1,800.0 X. E. 12 64 9 74 I.i\ er 0.0 Seemingly normal. Fat 0.0 X. E. 12 77 9 71 Liver 0.0 Light fatty change concentrated around major vessels Fat 494.0 X. E. 796 o" 28 l.i\ er 235.0 N. E. Testis 32 . 0 N. E. 7!»7 cf 48 Liver 1 1 1 .0 N. E. Testis 103.0 N. E. CONTROL 0 31 9 74 Liver 0.0 Slight vacuolation, otherwise normal; cytoplasmic crannies uniformly dis- tributed; cells polygonal, turgid; si- nusoids normal. Fat 0.0 N. E. * Not significant. It is well known that DDT accumulates in the tissues of animals that receive the chemical in their diets (Orr and Mott, 1!)4.">; Telford and Guthrie, 1945; Laug and Fitzhugh, 1946; and others). Its highest concentration is in the fat tissue, where it is reported to reach concen- trations up to 30 times that of the diet. Much less is known about the accumulation of toxaphene and clieldrin in animal tissue, but avail- able evidence indicates a behavior similar to that of DDT (Diephius and Dunn, 1949; Anon.. 1951). Our data are in essential agreement with these observations. From Table 3 it is seen that, with one excep- tion, birds maintained on insecticide-contaminated diets accumulated quantities of the chemical in their Eat. Moreover, pheasants maintained on diets containing either DDT or toxaphene had chemical concentra- tions in fat roughly proportional to the concentration of the material in the diet. This relationship did not hold true for the tissues of birds maintained on dieldrin, although here again the insecticide did tend to accumulate in the fat tissue. The low concentrations of the insecti- cides iu the livers of sacrificed hirds may he due to the detoxifying function of the organ, since much higher concentrations were found in the livers of birds that died of poisoning I Numbers 790, 796, 797; Table 3). 1"-' C VLIFORNIA PISH AND GAME DISCUSSION The chemicals discussed in tins paper were selected for study because there had been reliable field reports of game lnss from their use. Field mortality in mosl cases resulted from acute or short-term exposure. DDT on seed rice luis caused some mortality to pheasants and water- fowl (Rudd and Genelly, 1955 ; toxaphene applied to row crops and irrigated pasture lands lias apparently caused significanl mortality of pheasants; dieldrin applied to rice fur control of leaf miner resulted in verified loss of herons and egrets and in suspected loss of some other birds. Of the chemical applications mentioned above, only DDT appears to lie capable of causing game damage through continued exposure to sublethal dosages. Chronic poisoning of birds by exposure to DDT is strongly suggested in studies from the orchard areas of the State of Washington I Barnett, 1950). In those areas dosages of up to 50 and (it) pounds of DDT per acre are applied within a year. Single applica- tion rates of DDT in Californian orchards rarely exceed one and one- hall' pounds per acre, although two or three applications may be made annually. With the exception of the seed rice situation described above, DDT application rates in California are apparently not high enough to result in significant chronic mortality. When oils, miticides, and other insecticides are applied in the same areas in which DDT is used, these pesticides in combination with DDT may be sufficiently toxic to induce damage ('>/;. cit.). Toxaphene has a much shorter residual life than dieldrin and may not be expected to produce chronic effects of the same degree. Toxaphene is applied at rates of from 0.1 pound per acre in mosquito abatement activities to eighl pounds per acre on some row crops. It is difficult to translate surface application rates into the units used in experi- ment,! I analysis. The best data available indicate that values as high or higher than our experimental levels do result from normal rates of field application (Laakso and Johnson, 1949). A toxaphene emul- sion applied at four pounds per acre resulted in a field concentration of 165 p. p. m. Four months later the baled alfalfa still contained 55 p.p.m. In a similar test at eight pounds per acre, the field concentration reached 560 p.p.m. and baled alfalfa contained 274 p.p.m. Toxaphene dust applied at four pounds per acre resulted in concentrations of 45 p.p.m. in the field, and four months later of 30 p.p.m. in baled hay. Domestic geese showed signs of intoxication when exposed to toxa- phene spray a1 three pounds per acre and incurred mortality at four pounds per acre (Eyer et al., 1953). It would seem that values above two pounds per acre as spray and perhaps six pounds per acre as dust would be required to intoxicate pheasants. No direct evidence indicating chronic hazard of this chemical to any form of wildlife is available. Dieldrin has a residual life similar to that of DDT, but its insecti- cidal activity is much higher (Lidov et al., 1950). There is no field evidence available to indicate any chronic hazard, although acute poisonings are well known, in general, dosages of one-half pound per acre may be used effectively without hazard to warm-blooded animals. TOXICITY OP INSECTICIDKS TO PHEASANTS 13 At one pound per acre and higher, acute mortality may be expected. Normally, such dosages of dieldrin are not necessary for efficient insect control. SUMMARY Two hundred twenty-four ring-necked pheasants were maintained [jets containing one of three chlorinated hydrocarbon insecticides (DDT, toxaphene, and dieldrin) Tor periods ranging u|> to 94 .lays. In the fall test, M out of 10 females on 600 p.p.m. of DDT died within 57 days; 1 out of 10 females on 200 p.p.m. of DDT died after 90 days. During the spring test, all 4 males exposed to 400 p.p.m. of DDT died, while 20 females survived similar conditions. Such sexual differ- ence in susceptibility to DDT corroborates earlier observations. Thirty-three pheasants, including three males, survived exposure to toxaphene fed for two to three months, even at the highesl Level (300 p.p.m.). Dieldriu proved most fatal to pheasants. In the fall, G out of 10 females a1 200 p.p.m. died within 28 days, and 5 out of 10 females at 100 p.p.m. died within 38 days. In the spring, 8 out of 20 females and all 4 males at 50 p.p.m. died within 74 days. The only male tested at 25 p.p.m. died, while 21 females survived. With dieldrin as with DDT, the males appear to be more susceptible to poisoning than are the females. Declines in the weights of pheasants on toxaphene or dieldrin were roughly proportional to the degree of contamination of the feed. Most of the pheasants on DDT gained and maintained weights that averaged greater than those of the control birds, regardless of the concentration of the chemical. It is obvious that weight cannot be used as an exact index to the degree of intoxication of the bird. Samples of liver, fat, and testicular tissue taken from birds sacrificed at the end of the spring test period were analyzed for chemical con- tent and studied histologically. All birds examined had a high concen- t ration of insecticide in the fat tissue or showed marked damage to liver cells, or both. The livers of birds that were killed by the chemical contained recoverable amounts of insecticide, in contrast to the livers of sacrificed birds. Field evidence of game mortality in California induced by the con- tinued intake of small amounts of insecticide (chronic poisoning) is largely lacking. Recommended DDT application rates are not high enough to result in significant chronic mortality. However, there re- mains the possibility that, the use of a combination of pesticides on a single crop mighl induce game damage. Toxaphene applied at rates greater than two pounds per acre as a spray and six pounds per acre as a dust may be expected to result in acute mortality of pheasants. With dieldrin. as with toxaphene, there is no evidence of chronic pois- oning under field conditions. Acute mortality accompanies applications in excess of one pound per acre, but one-half pound per acre appar- ent lv offers little hazard to warm-blooded animals. 3—25467 14 C \l.!l'ui;\i \ PISH AM) GAME REFERENCES Alloll.N III. ill^ 1951. Insecticide Btorage in adipose tissue. Jour. Amer. .Med. Assoc., vol. 145, no. 10, p. 735 736. Barnett, Dan C. L950. The effecl of some insecticide sprays on wildlife. West. Assoc. St. Game and Fish C ., 30th Ann. Conf., Proc, p. L25-134. Bryson, M. J., C. I. Draper, .1. R. Harris, C. Biddulph, I». A. Greenwood, L. E. I Inn-. W. Binns, M. L. Miner, and I.. L. Madsen L950. DDT in eggs and tissues of chickens fed varying levels of DDT. Advances in che,,,. Ser., no. l, p. 2::2-u3<;. Dahlen, James II.. and Arnold < >. Haugen L954, Acute toxicity of certain insecticides to the bobwhite Quail and mourning dove. Jour. NVil.il. Mangt., vol. L8, no. 4, p. 477-481. I tiephius, Floj d, and < !. L. Dunn L949. Toxaphene in tissues of cattle and sheep fed toxaphene-treated alfalfa. Mont. State Coll. Agric. Expt. Sta., Bull. no. 461, p. 22-26. Eden, W. G. L951. Toxicity of dieldrin to chickens. Jour. Econ. Ent., vol. 44, no. 6, p. 1013. Eyer, J. K.. L. R. Faulkner, and R. T. McGarty L953. The effect of toxaphene and I > I >T on geese in cotton fields. New Mex. Coll. Agric. and Mech. Arts, Tress Bull. L078, p. 1-6. Kolthoff, I. .M.. and J. J. Lingane L952. Polarography. 2d ed., revised and enlarged. Interscience, X. Y. '.itio p. {■1 vol.) Laakso, J. \\\. and L. II. Johnson 1949. Toxaphene residues on alfalfa. Mont. State Coll. Auric. Expt. Sta., Bull. 161, p. 5-15. Laug, E. P., and O. G. Fitzhugh L946. 2, li-bis (p-chlorophenyl)-l, 1, 1-trichloroethane (DDT) in the tissues of the rat following oral ingestion for periods of six months to two years. Jour. Pharm. and Expt. Therap., vol. 87, no. 1, p. 18-23. I.idov. R. E., II. Bluestone, S. B. Soloway, and C. \V. Kearns L950. Alkali-stable polychloro organic insect toxicants, aldrin and dieldrin. Advances in Chem. Ser., no. 1, p. 175-183. Mohr, R. \\\. II. S. Telford, E. H. Peterson, and K. C. Walker 1952. Toxicity of orchard insecticides to game birds in eastern Washington. Wash. State (',.11. Agri. Expt. Sta., Circ. no. 170. 22 p. Orr, I.. W., ami L. < >. Mott 1945. T!n> effects of DDT administered orally to cows, horses and sheep. Jour. Econ. Ent., vol. 38, no. 4, p. 428-432. Rubin, M., II. R. Bird, N. Green, and R. II. Carter L947. Toxicity of DDT to laying hens. Poultry Sci., vol. 26, no. 4, p. 410-413. Rudd, Robert I... and Richard E. Genelly 1955. Avian mortality from I>I>T in ( "alifornian rice tields. Condor, vol. 57, no. 2. p. 1 17 1 iv. Telford, Horace S., and .lames E. Guthrie L945. Transmission of the toxicity of DDT through the milk of white rats and goats. Science, \o|. 102, no. 2660, p. 647. CHARACTERISTICS OF THE PELVIC GIRDLE IN RELATION TO SEX IN BLACK-TAILED AND WHITE-TAILED DEER' RICHARD D. TABER School of Forestry University of California, Berkeley INTRODUCTION A knowledge of morphological differences between the sexes of deer is Useful for hotll the field man Who wishes t0 sex ;i headless skeleton and the law enforcemenl officer who wishes to sex a butchered carcass. Three aspects of the pelvic girdle show sexual differences which are useful iii this regard. The present report describes and illustrates these differences for both the Columbian black-tailed deer (Odocoileus hemionus columbianus) and the Virginia white-tailed deer ((). vir- ginianus borealis) between the ages of two and ten years. Reliable criteria for age classes below two years have not yet been completely worked out. The material for the black-tailed deer is from the author's collec- tion from Lake County. California. That for the white-tailed deer originated in the State of New York, and was made available through the courtesy of Mr. C. W. Severinghaus of the New York Conserva- tion Department. Each specimen was assigned to an age class according to the cri- teria established by Severinghaus (1949) for the white-tailed deer and found applicable to black-tailed deer as well (Moreland, 1952). The bones of the pelvic girdle are the two innominates (or os coxae or H-bones) and the sacrum (Figure 1). Each innominate is made up of three bones — the ilium, the ischium, and the pubis — which fuse firmly by about 18 months of age. THE SHAPE OF THE PUBIC SYMPHYSIS AS AN INDICATOR OF SEX The two pubic bones, or pubes, come together face to face at the mid-central line, and the line along which they meet is called the pubic symphysis (Figures 1 and 2). Each of the faces which oppose each other at the pubic symphysis is called a symphyseal face. The shape of the anterior part of the symphyseal face in the male is different from that in the female. In the male it tends to be blunt. or prolonged forward slightly in its upper part, while it is rounded both above and below to give a roughly paddle-shaped outline. In the female il tends to be more slender, often dished in its upper forward part, while it may be flattened below. The symphyseal outline of the 1 Submitted for publication September, I !t. "in. Contribution from Federal Aid in Wild- life Restoration Projecl California W-31-R, "Effects of Brush Removal on Game Ranges in California," and the Museum of Vertebrate Zoology, University of Cali- fornia. (15) 16 ( Al.llitKMA FISH AM) GAME ANTERIOR SACRUM RIGHT INNOMINATE BONE PUBIS POSTERIOR FIGURE 1. Pelvic girdle of adult doe from above, showing the bones which make it up. The tail vertebrae have been removed. male may be likened to a soup spoon when the spoon is viewed from above, while that of the female is more like the soup spoon held upside down and viewed from the side. There is a great deal of individual variation, and the difference between the sexes, which may barely !)<• indicated al six months of age, becomes more pronounced as age advances (Figure 2). This difference was noted by Todd and Todd (1938, p. 9), who said. "In every artiodactyl (including deer) this sexual distinction is found, the male showing a symphyseal face bi- convex in outline, the female having an outline concave ventrally and convex dorsally." DEER PELVIC GIKDEE CHARACTERISTICS 17 Edelmann I 1!»4:{, p. 372) made a similar statement, based appar- ently on the authority of Whering and Schaff (reference not further identified), although it is not documented: "On the pubic symphysis the pelvis of tlie buck is thick and like a protuberance; that of the doe is thin, flat in front and slightly hollowed. It is emphasized by WHITE-TAIL ~ BLACK-TAIL CfvA Yr. 0*5/4Yr. O VA Yr. Q 5J4 Yr. DORSAL PUBIC SYMPHYSIS \ VENTRAL ANTERIOR \ POSTERIORY FIGURE 2. Righi. The right hindquarter of a buck, showing the position of the bones, and especially the cut surface at the public symphsis, which is shown as solid black. Leff. The cut surfaces, at the pubic symphysis, of both white-tailed and black-tailed deer, of both sexes, VA and 5V2 years old. Whering that the appearance of the symphysis can only be utilized with a degree of certainty in older deer as all the young individuals have a thickened protuberant symphysis. : The common stag and fallow deer show also similar sexnal differences in the pelvis." In the very young deer the two symphyseal faces are joined by cartilage. This cartilage gradually ossifies and by about the second to fourth year fuses with the adjoining ischia to hind the innominate bones rigidly together. When a carcass is cut in half, the saw cut passes longitudinally through the pubic symphysis. The shape of the cut face iii an adult deer will generally indicate the sex of the deer, because it will correspond to the symphyseal face. However, if the saw cut is very wide, so that both symphyseal faces are removed by the cut, or if the cut is made off to one side, the sawn face will do longer represent the symphyseal face and sexing by this means may not be possible. Because of the probability that {\vc\- land oilier hoofed mammals, to which these remarks also largely apply) will show genetic differ- ences in different regions, it is suggested that a reference collection of specimens of known age and sex he established for each area before an attempt is made to use this technique on a large scale. ] 8 < M.II'nKMA PISH AMI < I A ME THE SUSPENSORY TUBEROSITY OF THE ISCHIUM AS AN INDICATOR OF SEX In the buck the penis is supported by suspensory Ligaments which are attached to the arch of the ischium, or rather to the "inter-ischial bone" which forms a border around the arch of the ischium at the midventral line, binding the ischia together. Where the suspensory ligaments attach there are raised areas of hone called tnherosities. The principal ones arc Located halfway up the arch of the ischium— one no each side. The female docs not have any such tuberosities, so the presence or absence of the suspensory tuberosity is indicative of se\ Figure :!,i. The tnherosities become more distinct as the buck grows older. The suspensory ligaments of the penis also attach, in part, to the median ischial tuberosities; these thus become heavier in the buck than in the doe | Figure 3). h was stated that the suspensory tuberosity is actually a part of the inter-ischial hone rather than of the ischium itself. The inter- ischial hone is formed only in cartilage in the young deer. This car- tilage extends from the region between the opposing parts (the rami) of the ischia around the rim of the ischial arch to the ischial tuberosi- ties, which it covers. This cartilage is gradually ossified as age advances until, at about the second to fourth year, the portion covering the ischial tuberosities and the portion around the peak of the ischial arch have been transformed to hone and lightly fused to the underlying ischia. Within the next year or two ossification of the remainder of the inter-ischial hone is completed and fusion with the ischium at all points is accomplished. The relevance of these facts to the present discussion is this: if the pelvic girdle of a young animal is being cleaned for examination, the inter-ischial bone, which bears the sus- pensory tuberosities, may be separated from the rest of the pelvic girdle i:i the cleaning process. Obviously, care must be taken to prevent the loss of this diagnostic bone. THE RELATIVE SIZE OF THE PUBIS AS AN INDICATOR OF SEX Edelmann (1943), drawing on the work of Whering and Schaff, describes the sexual difference in pelvic proportions in these terms (p. • !7*_' i : "The pelvis of the doe, when viewed from above appears broader, more spacious, less slender than the pelvis of the buck; the distance of the outside angles of the ilium from each other is as .">() to 40." The relative size of the pelvic orifice, through which the fetus must pass, is understandably greater in the females of many mammalian species, especially those which, like the deer, have a pelvic girdle which does not separate along the symphysis at birth, and which bear rela- tively Large and well developed young. Washburn I 1948) found that in humans the size and shape of the pelvic orifice are related to the differential growth of the pubis (Figure 1) in the two sexes; in the female the pubis tends to be relatively larger than in the male, and the female therefore displays a broader orifice. This is apparently the cause of the broader pelvic girdle of females in the deer as well, and use may be made of this fact in dis- t inguishing be1 ween t he sexes. Relative proportions are most readily expressed as ratios; in this ease the depth of the pubic symphysis, which tends to be smaller in DEER PELVIC GIRDLE CHARACTERISTICS 10 females, has been divided by the distance from the face of the pubic symphysis to the lip of the acetabulum, which tends to be larger in females ( Figure 4 ). WHITE - TAIL BLACK-TAIL SUSPENSORY TUBEROSITIES a b a-- ISCHIAL TUBEROSITY b — b ISCHIAL ARCH FIGURE 3. Adult while-tailed and black-tailed deer of both sexes, showing the suspensory tuberocity in the buck and its absence in the doe. These pelvic girdles are upside down and viewed from the rear. When the depth df the symphyseal face of the pubis is taken, care must be exercised, especially in old specimens, to avoid including the inter-ischial hone in the measurement. This bone, lying between die ischia for most of its length, sends an anterior projection under the puhes ,it die symphysis in mid-adulthood, and when the pubic symphy- sis is sawn through this projection may appear superficially to be an integral part of the pubic bone. 20 ( VLIPORNIA K1SI1 AND Q \ \l I A series of these measurements on black-tailed deer of both sexes is given in Table 1. Dorsal acetabulum ischial tuberosities inter x ischial bone Ventral pubic symphysis S FIGURE 4. Right innominate bone of white-tailed doe, showing: A. measurement from ace- tabulum to pubic symphysis; and B. measurement of depth of pubic bone at the symphysis. The values in Table 1, which are ratios Symphysis depth ( Distance from symphyseal face to lip of acetabulum xlOO ) indicate that, in the black-tailed deer, bucks may be distinguished from does by this means. In the 2-3-year-old class the ratio in does was not over 35.4; thai in bucks was not under 37.8. In the older classes as a whole the ratios for both sexes were lower. After three years of age the does showed no ratio greater than 28.0 and the bucks no ratio less than 32.0. Values for the white-tailed deer, obtained iu the same way, tend to be larger; the maximum for female 2-year-olds is 42.4, for 3-year-olds 35.1, and for those over •'! years 2S.f), out of a total of 10 specimens of all ages. Two male specimens show a ratio of 43.6 for a 2-year-old and 35.3 for a 5-year-old. Thus, this method of sexing appears promising in the white-tailed deer bu1 more material must be examined before it can be accepted. The differences in ratio between the two species of deer indicate that yardsticks based on one species or race should be applied to another with caution. di:i:k i-klyic uikim.i: cm vha< tkristics L'l TABLE I The Symphysis Depth— Pubis Length Ratio for 49 Adult Black-tailed Deer \". ii years Sex 2-3 3 I I 5 :, 6 6 7 7 8 8 9 9 in Male 12.9 32 0 34.0 37.0 33 . 1 34 . .5 37.8 1 1 ;> 32.0 32.0 10. 0 36.0 43.0 -- -- -- -- -- -- -- Female 3 1 . 2 24.4 22 . 7 15.9 16.8 17.6 IS II 20.6 33 . 6 24 . 2 24 . 8 22.0 24.0 19.4 22.0 16 I 35 I 17.0 23.0 21.0 16.0 17.0 21.0 23.0 19.0 22.0 28 ii 19.0 16.0 31.0 26.0 22.0 IS II 21.0 26 n -- -- -- -- -- -- 16 n SUMMARY in both the Columbian black-tailed deer and the Virginia white-tailed deer, there are three principal characteristics of the pelvic girdle which indicate sex. One is the outline of pubic symphysis, which is thick and blunt in the male and more slender and pointed in the female. The second is the presence or absence of the suspensory tuberosity on the inter-ischial bone — the point of attachment of a suspensory ligament of the penis. The third is the relative length of the pubis, which is greater in the female. This may be expressed as a ratio of pubis length (from the symphyseal face to the lip of the acetabulum) to pubic symphysis depth. All of these characteristics become more pronounced with age. REFERENCES Edelmann, R. H. 1!>4.'!. Textbook of meat hygiene. 8th revised edition, revised l>.v J. R. Mohler and A. Eichhorn. Lea anil Febiger, Philadelphia. 468 p. .Mi >reland, Raleigh 1952. A technique fur determining age in black-tailed deer. West. Assoc. St. Game and Pish Comm., 32d Ann. ('(ml'.. Proc, p. 214-219. Sn eringhaus, < '. W. 1949. Tooth development in the white-tailed deer. Jour. Wildl. Mangt, vol 13 no. -2, v. 195-216. Todd, 'I'. Wingate, ami Arthur \Y. Todd 1938. The epiphysial union pattern of the ungulates with a note on Sirenia. Arner. Jour. Anat.. vol. <*>.".. no. 1, p. l-.",('.. Washburn, S. L. L948. Ses differences in the pubic bone. Amer. Jour. Physical Anthropol., vol 6 no. 2, p. 199-208. PROGRESS REPORT ON WHITE STURGEON STUDIES' RICHARD L. PYCHA University of Minnesota - St. Paul, Minnesota < hi April 1. l!i.")4, for the first time in 35 years, it became Legal to take sturgeon (Acipenser transmontanus and .1. medirostris) in Cali- fornia waters. Heavy commercial fishing had led to serious depletion by 1900. Earlier, they had been abundant enough to have been considered a nuisance. The commercial fishery was closed in 1901, reopened to a limited extent in 1910, and then closed completely in 1917. In recent years sturgeon have again become fairly abundant. On the basis of recommendations by the Department of Fish and Game, the commission established a sport fishery in 1!).~)4. with a one-fish-per-day ba» limit, a 40-inch minimum size limit, and no closed season. In order to gather information necessary for the future management 1 inches is therefore probably representative of the population. Angling records Erom San Pablo Bay and the entire Delta area also show very few iisli of thai size range caught. The implications of the length-frequency distribution will be discussed in a later section. SIZE OF SAN PABLO BAY WHITE STURGEON POPULATION Enough tagged tish were recaptured during the netting operation to estimate the sturgeon population in San Pablo May in the fall of 1954. A total of 966 was tagged, and 45 were recaptured ('Fable 2). The Donulati stiinate is: £ S (AB) 501,936 2 6' 45 where /' estimated population .1 number of fish tagged on a given day />' : number of tish tagged prior to the given day ( ' = number of recaptured fish in a given day's sample TABLE 2 Data for Estimation of White Sturgeon Population in San Pablo Bay (A) (B) (C) 1 Jay fished Number caught Total at large Number of tagged fish recaptured 5th 6th 7th 13 32 50 is 31 29 13 30 II 21 25 22 r,0 11 7 68 35 92 115 32 11' 35 36 49 1 55 186 233 279 309 336 349 377 416 139 till ISC, 53 i 574 581 644 676 763 868 898 '.i"f, 966 1 I 3 1 St!, 1 9th I Oth 1 (i 1 It!, 12th 13th 14th 15th 16th 2 1 1 (i (l (l 17th 1 0 1 9th 2 1st 2 3 in 23rd 2 24tl 4 26th 1 • Pishing was started everal daj before this day, but only a fe« flsta were caught and none recaptured. The 95 percent binomial eonfideuee limits are 8,806 and 15,784. The recapture by commercial fishermen of two tagged fish that had migrated out of San Pablo May while tagging was still in progress indicated the estimate may be too large because of migration of tagged fish from the fishing area. However, the time intervals at large of the recaptured fish ■WllITi: STURGEON STUDIES FIGURE 3. Locations where anglers caught sturgeon during the period April 1, 1954, to April 1, 1955. (Data from newspaper reports, Fish and Game warden reports, personal interviews, and communications.) 28 i ULIFORNTA KISII AND GAME TABLE 3 Frequency Distribution of Various Age Groups, Mean Lengths of Various Age Groups, Corresponding Values on "Faired-in" Growth Curve, and Annual Increments of White Sturgeon ^th Age group in u. n 1 II 111 IV V VI VII VIII IX X XI XII XIII XIV ! 6.0- 8.9 i :i •< 29 12 n ii 'i 1 18 i' - 1 2 1 24.0 26 8 1 27 0 29 9 30.0-32.9 2 ■ 15.9 5 36.0-38.9 1 16 2 1 39.0-41.9 21 4 4 2 1 42.0-44.9- 10 1 7 1 1 15 0 i: 9 2 4 4 1 3 1 2 i- n :,u 'i 1 3 1 1 2 51.0 53.9 1 1 3 54.0-56.9 1 5 ■'.: " 59 9 .... 1 5 60.0-62.9 63.0-65.9 1 66.0-68.9 69.0-71.9 72.0 71 9 :; 'i SO. 9 81.0-83.9 -1 (1 86.9 87 H H9.9_ !I2.9 93.0-95.9... No. fish. 30 2 6 1 54 12 20 4 6 1 : 2 IS \ Length 10.4 is II 21.2 31 5 39.8 43.0 44.6 42.8 15 5 55.5 51.0 52.5 54.7 red-iii" 10.5 18.0 23.0 28.0 32.0 35.3 38.5 41.0 43.0 45.8 47.9 50.0 51 5 ,Vi s Increment 10.5 7.5 5.0 .", ii 4.0 3.3 3.2 2.5 2.5 2.2 2.1 2.1 2.2 2.3 2.3 WHITE STUROKON STI I'll- I'!) TABLE 3— Continued Frequency Distribution of Various Age Groups, Mean Lengths of Various Age Groups, Corresponding Values on "Faired-in" Growth Curve, and Annual Increments of White Sturgeon XV XVI XVII Will XIX XX XXI XXII XXIII X X 1 \ XX\ \\\l XXVJ] XXVIII XXIX XXX 1 29 1 3 I 1 2 5 20 32 20 17 6 14 3 7 3 18 8 19 5 38 11 36 9 4 66 ■4 35 5 .' 1 1 48 3 19 5 3 -' 1 34 6 7 3 1 1 18 2 5 3 1 11 1 1 2 4 1 1 1 3 1 1 2 I 1 2 1 1 35 1 25 H) 15 6 5 2 2 1 1 1 S 56.6 60.2 62.3 64.3 68.5 69.9 IUI II 79.5 79.5 82.5 94.5 ! 59.0 61.2 63.6 lili.O 68.3 70.7 73.1 75 5 78.0 80.4 s2.s -*:.: 90.2 92.8 " 2.2 2.2 2.4 2.4 2.3 2.4 2.4 2.4 2.5 2.4 2.4 2.4 2.5 2.5 2.6 2.5 30 I U.II'oKM A PISH AND GAME gave ii" evidence of .1 systematic migration through the bay, so this is probably n<>t ;t serious source <>t' error. Fin raj sections gave qo evident E growth during the brief tagging period, and mortality is believed to have been negligible. Aside from one fish caughl by the Petersen . Tags were removed from five other fish by commercial salmon fisher- men who caughl them while salmon fishing, and several others have been reported caught, hut the tags have not been returned. The frequency of sturgeon catches in the Sacramento and San Joa- c | ii i ii rivers in the spring, and in San Pablo Bay in the fall (Figure 3 . suggests an annual winter or spring upstream migration and sum- mer downstream migration of large fish. Small fish less than 40 inches long seem to be present throughout the Delta area all year. Columbia River sturgeon are known to enter the ocean (Bajkov, 1951 ). Knowledge of the extent to which Californian fish enter the ocean is incomplete. Occasional catches by commercial fishermen off the central California coast have been reported, but the origin of these fisli was not known. Tagging data are expected to further clarify this phase of the life history.3 VALIDITY OF THE FIN RAY AGE DETERMINATIONS The till ray method of age determination has been well validated tor other sturgeons, bu1 not for this species. Pinal validation is im- possible with only a single year's collection. However, indications are that the method is valid. The number of "annular" rings per section increases progressively in the expected manner with the size of the fish (Table 3). Age group modes correspond reasonably well with length-frequency modes for at least the first six years. Moreover, large numbers of six- and sixteen- year-old fish correspond almost exactly with the two modes of the length-frequency distribution, suggesting a typical dominant year class type of age distribution. if i here are si roiej seven- and seventeen-year-old "roups in a large 1955 sample, the method will he well validated. A sturgeon tagged November 5, L954, in San Pablo Bay, California, was recovered in the ( lolumbia River near Astoria. < iregon, on October 26, 1955. WHITE STURGEON STUDIES :;i AGE COMPOSITION OF THE STURGEON POPULATION It is apparenl from the age class distribution (Table 3) thai spawn- ing success of sturgeon lias fluctuated greatly. Age groups VI and X Y I comprised 50 percent of all the fish over four years old. Age groups IX through XIII contained only 15 fish, ami all age groups older than XX were also poorly represented. Most Large fish that hit the nets could be seen, and few arc believed to have escaped. If tin- Near classes before 1!).'!(i I ;i»v group XYII1 I had been very abundant, more should have been caught. Since sturgeon weighing several hundred pounds were once common. it seems safe to assume that natural mortality is very low and could not account for the present scarcity of fish older than 20 years. The bulk of the stock now available to anglers came from the 1!r.!7 through 1!>40 year classes, with the 1938 year class providing most of the fish. From all indications another sizable year class (1948) is just enter Lng the fishery. Its relative size is uncertain, because many of the fish were probably too small to catch in the nets used. Many of the small fish observed going through the nets may have been slow-growing members of the 1948 year class. GROWTH IN LENGTH The first fin ray was commonly fused with the second ray and grown around it, making back calculations of growth impractical. Moreover, growth of most fish appeared to be relatively constant from year to year, making back calculations of little use in validating age deter- mination. Lengths at capture of the various age groups have therefore been used to express growth. Mean total lengths for each age group were calculated (Table 3) and plotted against age (Figure 4). One year was added to each age IUU s< 80 i^^» ^**" 1 M60 Ui I o 2 ? 40 ,^,*« ^^ • ***• *"• 2r X z u _l 20 8 10 ! 14 16 18 20 22 24 26 28 30 32 AGE IN YEARS FIGURE 4. Growth in length of white sturgeon. 32 i \i.irin;\i \ PISH and G \ \u: group because one growth season was presumably completed after the lasl .- 1 1 1 1 1 1 1 1 1 1 — . An approximate growth curve was then "faired-in" Table 3 . Annual length increments are Large Eor the first Eour years, but decline to a nearly constant incremenl of 2.1 to 2.6 inches after the ei-_rhtli year (Table '■'> . Although some dilferences in growth rate be- tween the sexes mi'jlit he expect ei I. data were insufficient to clarify this point. Sturgeon begin to reach the 40-inch minimum legal length in the seventh growing season, and almost all of them do so by the ninth iM'iiw in'j season. [f growth in length continues at a similar rate after the thirtieth year, the 14- to Hi-foot specimens reported in the early days of the fishery must have been 60 to 75 years old. GROWTH IN WEIGHT The total Lengths and weights of 163 sturgeon caught by anglers, and of several small fish taken at the Tracy Pumping Plant screens, were plotted to determine the length-weight relationship (Figure 5). The regression Line did not appear to be a simple curve, so an approxi- mate line was •• faired-in. " Weight increases slowly until the fish are about 35 inches, after which it speeds up. It slackens again between 50 and 60 inches, in- creasing again beyond that length. The unusual change in slope of the regression curve between 40 and 55 inches should be noted. Most fish in the 50- to 53-inch range weighed between 35 and 50 pounds, while those in the 40- to 43-inch range weighed only 12 to 20 pounds. 140 120 • • i ' ■ 80 o z O a. z 60 H I tu i 40 20 '/: * , • 1 / .:. * 1 1 * • • •■•• 10 20 30 40 50 60 LENGTH IN INCHES 70 80 90 100 FIGURE 5. Length-weight relationship of white sturgeon. WHITE STURGEON STUDIES 33 •20 100 S 80 z o 0. 5 60 H- X O UJ * 40 20 4 6 8 10 FIGURE 6. Growth in weight of white sturgeon. 12 14 16 18 20 22 24 26 28 AGE IN YEARS A commercial sturgeon fisherman on the Colnnihia River informed the author that the smallest female sturgeon with ripe eggs lie had seen weighed about 35 pounds. It is therefore possible that the inflec- tion in the length-weigh.1 regression is connected in some way with sexual maturation. By combining the data on growth in length and the length-weight relationship, a general curve of growth in weight is obtained (Figure 6). Weighl increases slowly during the firs! 6 years, increases rapidly between 6 and about 12 years, increases more slowly from 12 to about 20 years, and inereases very rapidly again past 20 years. The largest sturgeon weighed in 1954 was 102 inches long and weighed 277 pounds. MANAGEMENT IMPLICATIONS OF THE STUDY The tagging done in San Pablo Bay indicates that the sturgeon population is large enough to support a small, carefully regulated sport fishery. The angling catch is still small, but increasing. The large size, game- ness. ;iik1 excellent table qualities of sturgeon have created much interest among sportsmen, and ;i tew individuals have learned how to catch them in some numbers. The commercial gill net fisheries also :; 1 I Al.ll'nKN I A PISH AND GAME kill an undetermined number of sturgeon each year while fishing for salmon and shad. The general depletion of must sturgeon fisheries in the western hemisphere is a warning thai careful management of these fish is i essary. The angling regulations established in 1954 were based on the best information available at that time. Results of this present study indi- cate that they were too liberal in some respects. Pish uf the present 40-inch minimum legal length are about eight years old and weigh only about 15 pounds. A 50-inch fish weighs 38 pounds or more, and is only four or five years older. Moreover, the game qualities of sturgeon are mediocre until they reach 50 inches. A 60-inch fish is a real challenge to the angler. The sturgeon fishery should be managed so as to maintain a sizable reservoir of large fish both as a spawning stock and a buffer supply for periods of low recruitment. This should also provide maximum recrea- tional benefits. It is particularly important to protect the broodstock of a species such as this which does not begin to spawn until a fairly ad- vanced age, and which appears to produce a strong year class only about every 10 years. While age at sexual maturity has not yet been determined in Cali- fornia, the available evidence from Columbia River fish suggests that the females are probably not mature before 11 to 12 years. since several fish over 100 pounds and one weighing 277 pounds were taken in lfi.ll. and since anglers on the Columbia River take sturgeon weighing well over 300 pounds, it appears that large sturgeon can be harvested by angling. The present sturgeon sport fishery appears to be supported princi- pally by the 1937 through 1940 year classes, with the 1938 year class making up the greater part of the production. The next strong year class was spawned in 1918 and is just entering the fishery. The fishery is therefore dependent upon a very few widely spaced year classes. Under heavy exploitation, wide fluctuations in abundance of legal-sized fish could be expected. Heavy exploitation is possible, as demonstrated by the taking of I'M si urgeon in San Pablo Bay by one party boat between September 23 and November 28, 1954. An even greater number was taken prior to this period by trolling with snagging gear. Trolling has since been made illegal. The size of the spawning stock necessary to maintain the California sturgeon fishery is not known. The 40-inch size limit could possibly lead to reduction below the optimal level. It is therefore recommended that the minimum size limit be raised to 50 inches. The fishery depends, at present, primarily on fish larger than 50 inches, so little immediate reduction in total catch is to be expected. However, the large existing crop of fish under about 45 inches would be protected and allowed to grow to a size worth catching. In order to fully utilize the growth potentialities of the species, the average size of the catch should be maintained well above 50 inches. A decrease in average size to a point near 50 inches will indicate over- exploitation. The angling catch should therefore be sampled regularly in the future to follow trends in average size. WIlITi: STlKnioN S'lTDIKS 35 Under proper management, the California sturgeon population should provide recreation for considerable numbers of fishermen, along with the rare opportunity of catching a really large fish in inland waters. ACKNOWLEDGMENT The invaluable assistance of Vim-cut Catania, Nel Man and Boat- swain, in carrying out the field work is gratefully acknowledged. SUMMARY After 35 years of complete closure, a sport fishery for sturgeon (Acipenser transmontanus and .1. medirostris) was established in Cali- fornia in 1954. A life history study of the former was begun to evaluate the one-fish-per-day-bag Limit, 40-inch size limit, and the no closed sea- son regulations. A total of 1,003 sturgeon ranging in size from 31 to 94 inches was captured with trammel nets in San Pablo Pay, tagged, and released. Pectoral spine sections were collected from the fish tagged and from fish taken by anglers for age studies. The recapture of 45 fish while tagging gave a total population esti- mate of 11.154 fish in San Pablo Bay. In the first five months after tagging, only six tags were turned in by anglers and five by commercial fishermen. Only two fish were recaptured upstream in the Sacramento River. The frequency of angler catches suggests a winter or spring up- stream migration and summer downstream migration of large fish. Small fish appear to be nonmigratory. The fin ray method of age determination appears to be valid. Fish from 0 to 30 years old were aged, with age groups VI and XV \ com- prising about half of all fish taken. Recruitment was very poor prior to 1936 and from 1940 to 1947. Another large group of young fish is just entering the fishery. Sturgeon attain a length of 40 inches in the eighth year, 50 inches in the 13th year, and 94 inches in the 30th year. Weight increases slowly with length up to 35 inches, increases rapidly between 35 and 4.") inches, slackens somewhat between 50 and 60 inches, and increases rapidly beyond that length. Exploitation of sturgeon is still at a low7 level, but is increasing. Be- cause of the great increase in weight between 40 and 50 inches, and because of the wide year class fluctuations, a 50-inch size limit is recom- mended to provide a buffer stock of large fish for anglers and to insure maintenance of an adequate spawning stock. REFERENCES Bajkov, A. D. 1951. Migration of white sturgeon (Acipenser transmontanus) in the Columbia River. Fish Comm. Oregon, Fish Comm. Res. Briefs, vol. '■>, uo. '_'. p. 8-21. < !uerrier, Jean-Paul 1951. The use of pectoral tin rays for determining age of sturgeon and other species of fish. Canadian Fish Culturist, no. 11. p. 10-ls. Pycha, Richard L. 1955. A quick method for preparing permanent fin-ray and spine sections. Prog. Fish-Culturist, vol. 17. no. 4, p. 192. Schnabel, Zoe E. l'.».".s. 'I'h,. estimation of total fish population of a Like. Anier. Math. Monthly, vol. 4.", no. t;. p. .••,4s-::.-,'_\ FURTHER OBSERVATIONS ON STREAM SURVIVAL OF KING SALMON SPAWN' HAROLD A. GANGMARK and ROBERT D. BROAD United States Fish and Wildlife Service Seattle, Washington INTRODUCTION An experimental hatching study of king salmon (Oncorhyuchus tshawytsclni i eggs in Mill Creek, a tributary of the Sacramento River, California, in the fall of 1952 suggested a direct relationship between Hoods and egg mortalities (Oangmark and Broad, 1955). This study was a part of a general investigation of the reasons for widely fluc- tuating survival rales of salmon from year to year. Further informa- tion mi the influence of floods being desirable, additional investigations were carried out during the 1953-1954 season as a part of the more general investigation at Mill Creek. In the experiments at Mill Creek incubating king salmon eggs were observed in their natural environment in order to determine the effect of various influences on survival of eggs near the southernmost limit of the spawning range of the species. Fertilized eggs from native king salmon were placed in containers which were buried in spawning riffles and covered with gravel to simulate natural conditions as closely as possible. One-fifth of the containers were removed from the stream bed at equal intervals during the incubation period. Laboratory examina- tion of the contents of each container was then made. The results were tabulated and related to various ecological conditions that may have occurred during incubation. During the later stages of the experiment some eggs could not be accounted for, even though the eggs were in plastic sacks. An accurate record of survival rates was kept by using samples of known size. THE EXPERIMENTAL AREA Several requirements for a suitable area for the tests were met by a site near Woodward's Gate (Figure 1 i. It would be accessible under heavy flows, since the stream at this point could spread laterally 150 feet before it would become much deeper. The area was well supplied with gravel of the size which Burner (1951) terms as medium ami small - less than six inches at its greatest breadth I. Finally, spawning salmon actually had used the riffle in the past. A controlled How stream was also desired, to compare survival in the absence of stream fluctuation. Approximately two miles from the mouth of .Mill Creek, an old channel which had become isolated from Hie main stream by silting and brush growth leads to the Sacramento 1 Submitted for publication June, 1955. (37 ) :<> ( M.II'iiKM A FISH AND (iA.MF ' PA K ^ FIGURE 1. Spawning riffle area used for Mill Creek hatching experiments at Woodward's Gate in 1953-1954, exposed at low water. River. This channel was dry except during high water, although some sections were fed by an underground spring. Permission was obtained to divert a controlled flow into this channel, ami to prevent flooding an earth fill dam was built across the entrance over a 30-inch culvert connecting the channel with Mill Creek. A head- gate was installed to control water flow through the culvert. RESULTS OF THE FIRST WOODWARD'S GATE EXPERIMENT Oh November 6, 1953, two female and four male king salmon were obtained from .Mill Creek and were artifically spawned, using the hatchery dry method described by Cameron (1940). The eggs were then placed in a hatchery type egg basket in the current of the stream. After water-hardening for II hours, 100 eggs were placed in each of the numbered sacks, together with small amounts of gravel. The sacks were gently set into the depressions prepared for them in the stream bed at Woodward's Gate and were covered to the level of the sur- rounding gravel. The planting scheme was such that each removal group would represent as much of the whole planting area as possible. Each nest was protected from spawning salmon by a piece of wire netting 2 feet square anchored over it. The lirsl 50 sacks contained eggs from one female, and the second ")() sacks contained eggs from the second female plus some from the first. Knowledge of the time interval required for hatching was needed in order to divide the entire trial into equal periods. Past temperature records for Mill Creek indicated that approximately 1,000 heat units would be required for hatching. STREAM SURVIVAL OF KING SALMON SPAWN ::!) When the sacks of eggs had been l>u ii<< I for three days, the first group was removed to obtain information on the handling loss. The next group was removed when the accumulated heal units approxi- mated 20 pereenl or 250 heat units. Other lots wen' removed on a similar schedule of approximately 500, 750, and 1,000 heat units. The daily temperatures and heat units during the experimental period are shown in Table 1. After the sacks had been removed From the stream bed, the eggs were separated from the gravel and placed in bottles containing a TABLE 1 Mill Creek Stream Hatch ng Experiment Heat Unit Accumulation During Winter of 1953-54 Date Mean daily stream temp., Heat units Sub-totals Date \ I ran daily stream temp., Heai units Sub-totals °F. Expt. 1 Expt. 2 °F. Expt. 1 Expt. 2 Nov. fi 1 1 X Dec. 21 47 1.5 7 53 21 22 44 12 8... 51 19 23 43 11 '.i 51 19 24 42 10 755 519 10 51 l!i 25 43 11 11 52 20 26 44 12 12. 53 21 27 45 13 13... 53 21 28 44 12 1 1 53 21 29 43 11 15__. 52 20 30 42 10 16... 51 19 31 42 10 17. _. 49 17 Jan. 1 42 10 18_._ 44 12 X 2 42 10 19 44 12 3 44 12 20... 44 12 257 1 45 13 21 44 12 5 44 12 22 17 15 6 44 12 23 50 18 7 45 13 24... 50 18 8 44 12 25... 51 19 9 42 10 26. __ 50 18 10 43 11 27. _. 50 18 11 45 13 28.. _ 49 17 12 44 12 29... 48 16 L3 . 42 10 983 71\ 30... 48 16 14 43 11 Dec. 1_. 48 16 15 44 12 2 47 15 16 46 14 3 47 15 17 46 14 1 47 15 18 44 12 .". 45 13 498 265 19 44 12 6 15 13 20 43 11 7... 45 13 21 11 12 8... 45 13 22 45 13 9... 45 13 23 46 14 Ill 45 13 24 44 12 11 44 12 25 12 10 L2 43 11 26 42 10 13... 43 11 .'7 13 11 14... 45 13 28 44 12 15... 46 14 29 46 14 16... it; 14 30 46 14 17... 17 15 31 16 14 18... 48 16 Feb. 1 48 16 19... 19 17 2 48 1(1 20... 50 18 3 4 17 17 15 15 1031 \ day planted 10 i AI.II'nKM \ PISH AND GAME Ol "(5 o E in 3 ■1. c 3 /. 3 11 c /. 3 _0 S o a "3 C r - /. II - = s s & - _ i = e a r. S ' 0 §^ C Six sacks moved from angina! \< ■ — • 1 1 m- i in. apparently normal alevin hatching from moldy shell. Worms in one - i — C -~ -f oo -r co cn 01 -r r. ei t- ^e 3. (3 ei ei — X — ie >e o ■- = = _5- O o d c C d O o d O o d c c3 ei i q d c o d o d ■3 W (3 •e ei — o u .2 a — 3 in co X X X -r 1- - X X o ^ X i O « ' c 3 B1 si =. o o < o d o o d ■ K5 X x d 01 co d c. r- d Moldy and/or ruptured o o d — c -r ■* — — co i re — X \ co cm i CO ' -f C3 i CI U5 i ce t^ t^ i CO i-l i Original number of eggs c o 8 2 -r -* to i co x i X CO n r. 3. X 1 X CO re i-h — ~. OS ce CO CI ' CO ".O x oo i X Ol • a *- -o T3 C 03 ft 3 O fc. "3 > o z i i i i i re '- 1 S ! a <- 4 rH i-H co X :- ! * re i ,. ' o -1 1 _ -r CI ~ X X re 1 1(5 • e CO i-i to ce ■ e 1 s ' T ei if —• CO i >i '< 1 ■* i in i 1 \ 1 CO :S tj •ra co STREAM SURVIVAL OF KING SALMON SPAWN 41 clearing solution of 1 part formalin, 1 part glacial acetic acid, and 14 pails water. Microscopic examination was required to detect early cell stages in those eggs removed shortly after planting. All other eggs showed the embryonic fish very clearly. Ten of the first 50 sacks, with eggs from the first female, had an egg Survival rate of Only 14.9 percent (Table 2). The low initial rate left such a small sample for measuring future mortalities that ihis sample was discarded from 1 he experiment . Since the eggs from the second female were much smaller, it was easy to distinguish them from the few larger eggs of the first female that were mixed with them in the remaining 50 sacks. The survival rate for the second female's eggs after .'! days was 57.6 percent. Car] (1939), in planting silver salmon (Oncorhynchus kisutch) eggs in gravel in a hatchery trough, experienced losses of 4(i.4 percent. lie offers the opinion that high mortalities arc the result of extra handling involved in counting the eggs. Thirteen days later, on November 20, the second group was removed. During this time, the mean temperature of Mill Creek dropped from 55° F. to 44° F. On November 14. during a freshet, the mean stream flow increased to 49] c.f.s..- 7 times the mean recorded at time of planting. This group survived at a rate of 34.4 percent, which is a drop of 23.2 percent from the first removal (Table 2). A third group was removed on December 5, after 29 clays in the gravel. Laboratory examination showed a survival of 12.9 percent. This group had again been exposed to a stream freshet. Mean daily flow for November 24 reached 515 c.f.s.; an increase of over 7 times that re- corded when the eggs were planted. Temperature during this time rose from 44° F. to 51° F. and dropped again to 45° F. when the group was removed. The fourth group was collected after 48 days. In the period between the third and fourth removals, flows remained rela- tively stable. Temperatures fluctuated somewhat, reaching 50° F. and dropping to a low for the season of 42° F. Two and three-tenths percent of the embryos per cartridge were alive. On January 13, the fifth group was removed, after a total of 68 days or 983 heat units. Flows and temperatures remained stable between the fourth and fifth removals. A survival of 5J percent was recorded. The eggs were in the process of hatching when removed. Better indicated survival of the last group than the fourth group is a result of sampling error. The daily mean temperatures and stream flows are plotted in Figure 2, along with the various survival rates. Here it can be seen that early freshets were accompanied by rapid declines in survival, while stable flows that fol- lowed produced less mortality. A relation between the occurrence of freshets and survival rate was thus suggested. Freshets the year before (1952-1953) (Gangmark and Broad, 1955 occurred late in the incubation period, in contrast with their early occurrence in the experiment just described. The time of major egg mortality corresponded with the freshets. In 1952-1953 average losses of 1.1 and 7.7 eggs per sack were recorded between the tirst to second and second to third removals, respectively, when the stream Unci nation 2 Water How records were obtained from the State of California Division ol Water Resources. Their stream Hew- gauge is located one-half mile downstream from Woodward's « ;;tt>-. 42 i OJPOBNIA FISH AM) GAME 10 20 November 10 20 December 10 20 January FIGURE 2. The fluctuations in stream flow and temperature of Mill Creek and percentages of survival of egg samples during the first study in 1953-1954. was moderate. A loss of 18 eggs per sack was experienced between the removal of the third and fourth groups, when the mean flow for one day reached 1,250 c.f.s. RESULTS OF THE CONTROLLED FLOW CHANNEL EXPERIMENT There appeared to be a correlation between occurrence of marked stream fluctuation and survival. Therefore, a controlled flow channel experiment was carried out for purposes of comparison. On Novem- ber 18, 1953, spawn was taken from two female and three male king salmon. Standard hatchery procedure was followed for obtaining the spawn as before. The eggs were then allowed to water harden for 1| hours before being placed in the cartridges with some small gravel. Thirty of the containers were destined for Woodward's Gate, as an "pen channel control, and .'51 for the controlled flow area. They were selected alternately for each area and buried in the respective areas simultaneously. Again there were five colors of tags in each group. They were planted by a staggered distribution or by rotating the col- ored t;tgs. The temperature of the water at this time was colder (44° K. i than during the first plant. After two days, the first groups were removed. In the main stream, 03. (i percent of the eggs survived the handling operation (Table 3), and in the control channel, 52 percent (Table 4). Between this time and tin; removal of the second group, flows had increased to a mean of 515 c.f.s. from 152 c.f.s. at planting on November 24. At the end of this period, the cartridges in Mill Creek proper revealed a 37.2 per- cent survival in the second group, or a drop of 26.4 percent. This is STREAM SURVIVAL OF KING SALMON SPAWN 43 C3 en CO E co Cn en / .a a E IV i. CD XI eg c3 — : - 0 I§ 83 u CD " -g « o » 1= ■a 2 - J - bl ^ 0 o .- s fl '• - s = o C o / o a "a a :§ o S o o a = CO CD 03 CO 0 -6 -.* u 0 > CD E a si CD 0 318 63.6 11.4 223 37 . 2 26.3 160 26.7 9.6 136 14. 1 CO a CD 5 o o d o c d © o d o c d Partial develop- ment °. i o o c o f less i he same i ime Lnterva firsl experiment, in which a 21.5 percenl loss occurre< in thf two experiments for the same period were somewhal similar. In the controlled flow area 53.8 percenl of the eggs were alive after this period, indicating thai sampling error was responsible for a lower sur- vival of the first sample. However, there is a clear difference in survival rates between the two areas. Eggs in the main stream suffered a sub- stantia] loss as compared to an apparently good survival rale in the emit rol area I Figure '5 ). In the period thai followed until the third group was removed, when the salmon embryos were 36 days old, the temperatures and stream flows remained relatively stable. The survival rates in the two areas were quite similar. The main stream survival was 26.7 percent, a drop of 10.5 percent since the previous sampling. Embryos in the controlled flow area survived at a rate of 44.4 percent, a drop of 9.4 percent. At the end of 56 days, the eggs were sampled for the fourth time in the two areas. In the main stream, 22.7 percent were alive, an aver- age of 4 less per cartridge than in the previous sample. In the control area. -'57. S percent were alive, for an average of 6.6 embryos per con- tainer less than in the previous group. Again the temperature and stream How factors remained stable for this period. After the fourth group had been removed, stream flow suddenly rose to ;i high for the year. The water gauge at Mill Creek recorded a mean of 2,740 c.f.s. for the 17th of January. This represented a flow7 of 18 times the mean recorded on the day the eggs were planted. It will be recalled that the experimental area at Woodward's Gate was specifically chosen for its ability to carry large volumes of water. IIow- 10 20 November 10 20 December 10 20 January FIGURE 3. survival of The fluctuations in stream flow and temperature of Mill Creek and percentages of egg samples during the controlled flow and second main stream study in 1953-1954. STREAM SURVIVAL OP KING SALMON SPAWN 4.") CO Ol Ol a> en m ^ <* ^ 5 o Ol Ol Remarks Six eggs with mold on shells classified as alive. 6 > y. a o -a _3 c +3 3 3 3 a > 3j Number alive 312 52 . 0 18.3 oo ire ci *■* 1- CI •'. cc 311 44.4 14.8 227 37.8 14.0 123 20.5 5 . 5 Alexin^ 0 0.0 o O d © d o o d >re ■ c r*. •* i Partial develp- mont o o d O o d CD i- CC i CI 00 oo — -D — a — i u 286 47.7 ci oo i iO * i C CM i CM ' = O O I CI r~ — i Opaque o o d o o d ' CO ' CD CI o c d oo I- Cl Moldy and/or ruptured IN i rt d 181 30.2 301 43.0 o o w cc t- tN X Number of eggs found 599 99.8 ^ : CD tN "C (173 96. 1 14.7 210 til II Removal group ami date 1 11/20 s.d. ■> X s.d. 12/24 s.d.. 1/13/54 s.d. — — 4(1 CALIFORNIA PISH AND Q \MI. ever, the force of the currenl was sufficient to change the profile of the riffle and to dislodge the salmon embryos in the gravel. No evidence remained of the cartridges which were to be removed ■ hi February 4. after 7s days. The final tally was "JO..") percent alive for the controlled How ana. a decline of 17.3 salmon embryos pei- cartridge since the last removal. The stream temperature and flow records are shown in Figure 3 in connection with survival rates in the two areas. RESULTS OF THE JANUARY 17, 1954, FRESHET The high velocity Hows which occurred January 17 thoroughly flushed and changed the riffle area at Woodward's Gate. Stones of vary- ing size which had been painted white, numbered in black, and placed individually on each redd were no longer in position over the nests. Thirteen of the stones were found downstream at distances varying from S feet for a !>-pound stone to 525 feet for a 1.6-pound stone. The distances were measured from the downstream end of the planting area because most of the numbers had been worn from the stones. FIGURE 4. Sketch of Mill Creek planting site at Woodward's Gate. STREAM SURVIVAL OF KING SALMON SPAWN 47 The profile of the riffle a1 Woodward's Gate was 'hanged markedly. A channel Is inches deep was gouged through the area where 30 pairs of king salmon had spawned. The main stream was diverted from the east to the west side of a little island shown in Figure 1 and (i inches of silt was left on the east hank up to 15 feet from the water's edge. A check was made to determine to what extent the natural spawn was affected. NestS were explored with a hoe. and a hand net was used to catch any embryos which migh.1 he dislodged. From other samples of eggs, we estimated that the majority of the natural spawn would he in the early alevin stage, when the young fish require gravel to protect them from the pull of the cm-rent and from predators. Persistent dig- ging produced no eyed eggs or alexins. In an attempt to evaluate roughly the extent of main stream damage, other areas were excavated in a similar manner. Below Ward Dam the stream is divided into three channels. Tn the two smaller channels, each of which contains less than 25 percent of the total How of Mill ('reek, eyed eggs and alevins were discovered in the gravel. Such small chan- nels appear to be of considerable value in maintaining salmon runs, since the effect of flooding is less violent. p]\idence of loss of spawn was found at the mouth of Mill Creek, where water from the Sacramento River temporarily backed into Mill • 'reek. Several thousand dead eyed eggs were seen floating on the sur- face after the January 17th freshet. Also. 51 ryed eggs were found in the stomach of a 12-inch rainbow trout cauirht by a local sportsman after the flood. DISCUSSION Of the various factors that might have affected egg survival in our experiments, flooding is the most apparent. This influence has been so overwhelming that it has overshadowed other factors. More data are always desirable, but the effect of freshets in both the 1952-53 and 1953-54 work cannot be overlooked. This conclusion is based on the following: (1) the close correlation existing between egg losses and freshets in which stream flow increased by seven or more times; (2) the opposite survival trends for the two years in which heavy losses and extreme flows occurred late in 1952-53, compared with early losses ac eompanying freshets in 1953-54; and (3) the heavy e-- losses expe- rienced during an early period in the main stream in two experimental plants, in comparison with little or no egg loss during the same period in the control flow channel in 1953-54. The influence of freshets should not be confused with that of substan- tial stream Hows. Adequate Hows are especially important in the Sac- ramento Valley in California. First of all, the upstream migrants must have sufficient water to swim in and there must be enough water to maintain suitable temperatures and oxygen supply. See.. ml. stream flows must provide adequate area for adults to spawn without crowding. Third, there must be sufficient water flow throughout the incubation period to keep the eggs alive. Fourth, strong Hows during downstream migration increase turbidity and protection from predators, lessen the chance of the small fish being swept into irrigation intakes, dilute pol- lutants, and stabilize temperatures ami oxygen conditions in the streams. I- C \l.ll'iili\ IA FISH AND GAME As iii the ease of the analyses made on the data of 1952-53 (Gang- mark and Broad, 1955), no significanl difference in survival related to position of the cartridges in the stream was round. The analyses cov- ering the two seasons indicate that with the exception of the flow con- trol area, position of the cartridges in the stream lias not significantly affected survival in these experiments. ACKNOWLEDGMENTS Grateful acknowledgment is extended to Robert Azevedo of the Braneli of (iame-Kish and Hatcheries and to several members of the California Department of Fish and Game, for their assistance in con- ducting the experiments described herein. We Avish also to express sincere i hanks to Scott Bair, Hydraulic Engineer, Fish and Wildlife Service Regional Office in Portland, Oregon, for surveying and provid- ing plans for construction of the flow control dam which was built. SUMMARY Because of the correlation of king salmon egg mortality between the stages of fertilization and hatching in Mill Creek, California, with stream freshets in 1952-53, a controlled flow area was established to further investigate the problem in 1953-54. The technique for conducting the experiment involved enclosing fer- tilized eggs with gravel in plastic screen sacks and burying them in the streambed. The sacks were removed at five different stages and various influences that may have affected survival were noted. In one experiment involving 50 such sacks planted at Woodward's Gate, early losses were noted in the first two periods, in each of which a freshet occurred. The mortality rate was comparatively light during the last two periods, when stream flows remained stable. Early mortalities during 1953-54 accompanied early freshets. In 11)52-53 mortalities were at first small, while stream flows were stable. Mortalities increased with the occurrence of the first freshet, with com- plete loss following a subsequent flood. A second experiment in 1953-54 involved placing eggs in the Wood- ward's Gate section and planting a similar group in the controlled flow channel. Alain stream losses were heavy and in sharp contrast to a good survival rate in the control channel. In I lie two periods which followed this, stream Hows remained mod- crate and survival rates were comparable in the creek and controlled How area until January 17, 1954, when a freshet occurred. Results of this freshet on the Woodward's Gate area were: (1) com- plete erosion of the streambed; (2) loss of experimental cartridges and natural spawn from the riffle; and (3) a change of the channel and a heavy deposit of silt on the banks. Eggs in the controlled flow area suffered mortalities from silt deposition only. After the freshet only areas in which the rate of How was reduced by the stream dividing and subdividing produced eggs and alevins. Further indication of spawn losses after the flood were numerous lloating rvi'd eggs which were seen at the month of Mill Creek. A rain- how trout caugh.1 after the freshet, was found to contain many king salmon effffs that had been eroded from the gravel. STREAM SURVIVAL OP KING SALMON SPAWN 49 Severe freshets or violent stream fluctuations should be distinguished from substantia] stream Hows, which are beneficial to virtually all phases of the freshwater Life history of salmonids. An analysis of variance revealed thai position in the stream had ao1 significantly affected survival in these experiments. LITERATURE CITED Burner, Clifford J. 1951. Characteristics of spawning nests of Columbia River salmon. I'. S. Fish .•ind Wildl. Serv., Fish. Bull., vol. 52, qo. 61, p. 97-110. Cameron, M. W. 1940. 'I'll" efficiency of fertilization in tin1 natural spawning of Pacific salmon. Fish. Res. Bd. Can., Prog. Repts. Pac. Coast Sta., no. 15, p. 23-24. C.irl. G. Clifford 1!>40. Comparison of <-i>h<> salmon fry from eggs incubated in gravel and in hatchery baskets. Amer. Fish. Soc, Trans., 1939, vol. 69, p. I-".'-' !•".(. Gangmark, Harold A., and Robert D. Broad L955. Experimental batching of king salmon in Mill ('reck, a tributary of the Sacramento River. Calif. Fish and Game, vol. 41, no. ■"., p. 233-242. AN ECOLOGICAL STUDY OF LOWER SAN GABRIEL RIVER, CALIFORNIA, WITH SPECIAL REFER- ENCE TO POLLUTION' '2 DONALD J. REISH Allan Hancock Foundation and Department of Biology University of Southern California, Los Angeles -; INTRODUCTION An ecological study of Lower San Gabriel River was carried out by the California Department of Fish and Game in 1952, in connec- tion with iis program of studying the fish and other aquatic life re- sources of California's hays and harbors. This area was found to he very polluted in 1 952, as will he discussed below. In the fall of 1952, a section of the sampled area was diked and excavated under contract with the Los Angeles County Flood Control District as a flood control measure. In 1954 Lower San Gabriel River was resampled to determine what effect this excavation had had upon bottom conditions. If pol- lutants were again accumulating on the river bottom, some indication of the length of time required to reach the conditions evident in 1952 could be obtained. The term Lower San Gabriel River is used to denote that portion of the river which has marine or brackish waters. It is important to distinguish between dictionary and California Legislative definitions of the word "pollution". A dictionary definition is "the act of making or rendering unclean", whereas in Division 7 of the "Water Code of the State of California, under which the State and Regional Water Pollution Control Boards operate, pollution means "an impairment of the qualit}7 of the waters of the State by sewage or industrial waste to a degree which does not create an actual hazard to the public health but which does adversely and unreasonably affed such waters for domestic, agricultural, navigational, recreational or other beneficial use." In this study the author employed the dictionary definition of pollution. A summary of marine pollution studies in California was given by Reish and Winter (1954). Later, Filice (1954) described the ecology 'Submitted for publication March, L955. Contribution number L65 from the Allan Han- cock Foundation, University of Soutnern California, Los Angeles. J The hazards of pollution of California's coastal areas, including both marine waters and outlets of streams, are increasing- as the population and industrial develop- ment of the State increase. To meet and solve tnis problem, detailed investigations must be made of many areas and indicators to measure the magnitude of such pollution must be established. This report is a facet of the over-all pollution studies being undertaken by various agencies in the state, h'ditor. -This work was sponsored in iiir.2 by the California Department of Pish and 'lame, which served as a technical consultant to Regional Wat< r Pollution Control Boards Numbers 4 and 8. The 1952 study was initiated and requested by the Los Angeles Regional Water Pol- lution Control Board and pursuant to this request, the Department of Pish and i lame submitted a report to the board entitled, "Lower San Gabriel River Survey — July, 1952 — Special Investigation Project No. 52-4-11." The work was supported in 1954 by a research grant (E-556) from the National -Mi- i i '.biological Institute of the National Institutes of Health, United States I'ublic Health Service. (51) 52 i Al.ll'oKM A PISH A\|i GAME OIL FIELDS **%&> OIL FIELDS P.E.R.R.W*TSp*< hiiHW- CITY OF SEAL BEACH MAY 2, 1952 JULY 15. 1954 STATION LOCATIONS LOWER SAN GABRIEL RIVER, CALIF WATER POLLUTION SURVEYS 750 YARDS FIGURE 1. Station locations and major sources of pollution, Lower San Gabriel River water pollution surveys of May 2, 1952, and July 15, 1954. A, outfall from the Los Angeles Bureau of Water and Power Steam Plant. B, outfall from the sewage treatment plant of the City of Seal Beach. C, outfall from the Dow Chemical Company. D, outfall (east shore) from the sewage treatment plant of the Los Alamitos Naval Air Station. E, outfall from the Santa Fe Springs Waste Disposal Company located northeast of Station 14. I.i ni.ocM'AI; STUDY OP SAN GABRIEL BIVEB TABLE 1 Lower San Gabriel River Station Locations Stat ion MUIIll.IT Descriptive location 1- 2. 3 1 5 6 7. 8 9 10* lit 12t 13f 14t Middle of river near mouth of San Gabriel River. Middle of river, 200 feet northeast of Ocean Blvd. Bridge, near Los Angeles Bureau of Water and Power Steam Plant. Middle of riser. I 50 feet southwest of Second Street Bridge. Middle of river, 150 feet northeast of Second Street Bridge. Middle of river, 150 feet southwest of Pacific Electric Bridge. Middle of river, l.">0 feet northwest of Pacific Electric Bridge, near City of Seal Beach outfall sewer. Middle of river, 200 feet southwest of Pacific Coast Highway (U.S. Alternate 101). Middle of river, 300 feet northeast of Pacific Coast Highway (U.S. Alternate 101). Middle of river, 1.100 feet northeast of Pacific Coast, Highway (U.S. Alternate 101). Middle of river, 2,300 feet northeast of Pacific Coast Highway (U.S. Alternate 101 I. Middle of tributary, 1,100 feet east of Pacific Coast Highway (U.S. Alternate 101). Middle of tributary, 2,000 feet northeast of Pacific Coast Highway (U.S. Alternate 101). Middle of tributary, 2,500 feet northeast of Pacific Coast Highway (U.S. Alternate 101 |. Middle of tributary, 4,200 feet northeast of Pacific Coast Highway (U.S. Alternate 101). * Not sampled May 2. 1052. t Not sampled July 15, 1954. of the Castro Creek area in San Pablo Bay, an arm of San Francisco Bay. with particular reference to pollution. Pilice divided the inverte- brate bottom fauna into three zones: (1) a healthy zone unaffected by waste discharges, (2) a marginal zone characterized by a few tol- erant species, notably the polychaetes Neanthes succinea (Frey ami Leuckart), Capitella capitata (Fabricius), and Streblospio h.V_\ During this time the river was diked between Stations 7 and 8 at the Pacific Coast Highway bridge. Water remained in the righl branch of the river I Figure l I until some time between October ::. l!>52, and November 20, 1952, when the river bed was observed to be dry. 54 < \ 1. 1 1 '<>K. VIA FISH AND GAME ~] I ll UlLi FIGURE 2. Lower San Gabriel River from a small bridge midway between Stations 9 and 10, looking southwest. The area between the place where the photograph was taken and the Pacific Coast Highway (Alt. 101) bridge was dredged in 1952. Photograph by the author, July 7, 1954. FIGURE 3. Lower San Gabriel River from the Pacific Electric Railroad bridge, looking south- west towards Station 4. Second Street Bridge is in the foreground. Photograph by the author, July 7, 1954. ii 111. o(,i( ai. STl in ok SA.N (i \i:i;ii I. l;l\ u; ;,.-, A total of 864,937 cubic yards of material was excavated, making the river bed deeper by an average of four to five feet. Figures 3 and 4 show portions of the river thai were not excavated. MATERIALS AND METHODS Lower San Gabriel River was sampled May 2, 1952, and July 15, l!l.">4, from a small skiff furnished by the California Department of Fish and Game. The temperature, dissolved oxygen, chlorinity, and pi I of the water were measured. A sample of the substrate was taken for pll and preserved for the animals it contained. Measurements and analyses of these data were carried out as described for Alamitos Bay (Reish ami Winter, 1954). Stations 11 to 14, located on a tributary of San Gabriel River, were not sampled July 15, 1954, since this ana was no longer accessible by boat (Figure 1). Additional trips were made to collect the high tide horizon animals (July 2, 1952) and meas- ure the pH and temperature of the water and substrate from shore (October 3, 1952, and November 20, 1952). SOURCES OF WASTE DISCHARGES INTO LOWER SAN GABRIEL RIVER The primary sources of waste discharge into Lower San Gabriel River during the 1952-54 period were: Dow Chemical Company (Fig- ure 1, C; Figure 4), Santa Fe Springs Waste Disposal Company (Figure 1. E). two domestic sewage disposal plants (Figure 1, B and FIGURE 4. Lower San Gabriel River from the Pacific Coast Highway (Alt. 101) bridge, looking southwest towards Station 6. Dow Chemical Company located in left center. The large smoke stack is a portion of the Los Angeles Bureau of Water and Power Steam Plant. The Pacific Elec- tric Railroad bridge crosses the river downstream from the Dow Chemical Company. Photograph by the author, July 7, 1954. 56 CALIFORNIA PISH AM) GAME D . and Los Angeles Bureau of Water and Power Steam Plant (Fig- ure 1. A i. The former two were the principal contributors of wastes discharged into the river during 1952 (California Department of Pub- lic Health, L952). The outfall sewer of Dow Chemical Company consists of a single pipe which empties the liquid waste into the river on the east shore midway between Stations li and 7, just southwest of the Pacific Coast Highway. This waste discharge was investigated on May 2, 1952, Oc- tober 3, 1952, November 20. 1952, and duly 15, 1954. The temperature of the discharge varied; it was twice observed as high as 40.0 degrees ('. (May 2, 1952, and duly 15, 1954) and once as low as 23.5 degrees C. (Oetober 3, 1952). The water temperature of the river in the immedi- ate vicinity of this outfall was affected by this warm discharge, but temperatures 150 feet downstream were observed to be normal. The pH of the liquid wastes ranged from 2.2 to 2.5. Normal seawater pH was not found as close to the discharge as was normal temperature. At 150 feet downstream the pH of the water ranged from 4.3 to 5.8. Normal pH of the water and substratum was noted at Station 6, a distance of about 700 feet. A strong acrid odor, noted at the outfall, was still pronounced 150 feet downwind. Xo living animals were observed in the vicinity of the Dow Chemical Company outfall sewer. Waste discharges from the Santa Fe Springs Waste Disposal Com- pany, which is located northeast of Station 14, northeast of the Pacific Coast Highway, consisted of brine from oil well drilling operations. No special investigation was made of this outfall. The two sewage treatment plants which have outfalls into Lower San Gabriel River are those of the City of Seal Beach and the Los Alamitos Naval Air Station. Both of these plants provide complete treatment with effluent chlorination of the discharge. The outfall of the City of Seal Beach is located on the southeast shore near Station 1535 19.5 7.95 18.8 8.0 7 6 3 1550 19.0 8.6 18.9 7.75 7.5 I 1620 L9.5 8.9 18.7 7.8 7.9 5 1635 20.0 9. 1 18.8 7.5 7.2 6 1 1;.-,( i 20.0 7.3 19.9 8.1 7 . 3 7. 1705 22.0 7.0 IS 1 6.8 7.7 8 1735 2 1 ■"> 6.95 17.8 6.2 6.8 !i 1755 1815 L845 moo 28.0 27.0 28.0 28.0 0.5 trace 0.0 0.0 12.9 15.8 11.1 8.1 6.65 7.'. 15 10.0 12.3 6.9 1 1 9.5 12 11.2 i:; 12.4 14 1930 26.5 1 r:ur 7.0 5.9 3 . 6 TABLE 3 Chemical and Physical Data— July 15, 1954 Station Time Tempera- ture in°C. Dissolved oxygen in p. p.m. Chlorinity in 0/00 PH number Water Substratum 1 0945 1010 1020 1030 1045 1115 1200 1305 1250 1230 22.0 28.0 21.0 27.5 27.0 27.5 27.0 28.0 28.0 28.5 7.6 7.4 6.8 6.8 7.2 7.3 5.8 4.4 3.0 0.0 19.3 19.3 19.3 19.5 19.4 19.0 19.6 l!l.5 19.3 18.3 8.1 8.1 8.1 8.1 8.0 8.05 7.5 7.3 7.4 7.25 2.. 7 6 3 7 7 4 . 7 5 5 7 6 6.. 7 1 7 7 1 8 6 9 9 6 8 10 6 7 I Ihlorinity was slightly below that of normal seawater (19.4 0 00) on May 2, 1952, at Stations 1 to 8, and the water was brackish at Stations .1 1 to 14, in the tributary. Only at Station 10, some 750 yards upstream from the Pacific Coast Highway, on July 15, 1954, was the chlorinity much below that of normal seawater. The pll of the water and substratum varied considerably from sta- tion to station ou May 2, 1952. Both water mass and substratum were slightly alkaline at Stations 1 to 6 and 11. and highly alkaline at Stations 12 and 13. The pll was slightly acid a1 Stations 8 and 9, but highly acidic at Station 14. In general, the pH of the substratum follows thai of the A\ater mass. However, exceptions were observed at Stations 7 and 14 od .May 2, 1954. At Station 7 the water was slightly acid (6.8) and the substratum slightly alkaline '7.7 . Ai Station II the pll of the water was acid (5.9), while thai of the substratum was highly acidic (3.6). The pll of the water mass and substratum were alkaline at all stations on July 15. 1954, excepl for the substratum at Stations 8 to 10, which was slightly acidic. 58 CALIFORNIA FISH AND GAME NATURE OF THE SUBSTRATUM The bottom on May 2, 1952, was coarse black sand at Stations 1 to 7, seaward of the Pacific Coast Highway, and black mnd at Stations 8, 9, and 11 to 14. upstream from the Pacific Coast Highway bridge. The substratum possessed a sulfide odor at Stations 3 to 8 and a petroleum odor at Stations !» and 11 to 14. No odors were detected at Stations 1 and 2, near the mouth of San Gabriel River. The substratum at Stations 2 to 7 was of the same consistency on July 1"). 1954, as on May 2, 1952. At Station 8 the bottom wras black mud and sand, with a slight sulfide odor. Stations 9 and 10 had a black mud upper layer, with gray mud beneath. No sample had been taken at Station 10 on May 2, 1952. No odors were detected at Stations 2 tn 7. 9, and 10 on July 15, 1954. No sample was obtained at Station 1 on July 15. 1954, despite repeated efforts. BOTTOM FAUNA No living bottom animals were taken on May 2, 1952, but fragments of clam and snail shells were obtained in the samples from Stations 1, 12. 13, and 14. (Stations 1 to 9 and 11 were revisited two months later, on July 2, 1952, in an attempt to determine whether or not pollution had affected the high tide horizon. At this time the intertidal surfaces of all but Station 1, located near the mouth of San Gabriel River, were covered with fine black mud having a sulfide or petroleum odor. Occa- sionally a thin layer of tan-colored sand overlaid the black mud. Barna- cles, Balanus sp., were found attached to rocks of the jetty at Stations 1 to 4, and the shore-crab, Pachygrapsus crassipes Randall, was found TABLE 4 Species and Number of Animals Found in the Bottom Samples Taken on July 15, 1954 Species Station numbers lotals 1 2 3 4 5 6 7 8 9 10 Sea Anemone 1 1 Turbcllarian 1 1 Nemertean 1 1 3 10 16 37 Polychaetes Neanthes succinea* Polydora nuchalis l'i inuox/iin v.irrife.ra Capitclla capitata* Capitita ambiseta IS 5, s to 0 z 2 2 41 2 108 5 231 105 2 34 1 2 151 6 269 105 Crustaceans Epinebalia sp. Callianassa californiensis 1 1 1 1 Pelecypods Macoma nasuta Tagelus californ ian us 1 3 1 3 Totals 1 1 1 2 5 57 474 36 1 578 * Indicator organisms, marginal zone (Filice, 1954). ECOLOGICAL STUDY OF SAN GABRIEL RIVER 59 al these same stations between the rocks. The tube-dwelling polychaete Boccardia proboscidea Hartman formed beds a1 Stations 3 and 4. insect Larvae were observed in the mud at stations 5 to 9 and 11. Oligochaetes were associated with the insect larvae al Stations I and 8.) Whereas no living animals had been found in the bottom on May 2, 1952, a total of 578 animals representing 12 species were taken during the survey on July 15, 1954 (Table 4). These included: a sea anemone, a turbellarian, a nemertean, five polychaetes, two crustaceans, and two peleevpods. Four hundred and seventy-four of the 578 specimens were taken at Station 8. The crustacean Epinebalia sp. was the only species of the 12 not found at Station 8, just upstream from the Pacific Coast Highway and within the area excavated by the Los Angeles Flood Con- trol District in 1952. All except Prionospio cirrifera Wiren, Epim balia sp., and the sea anemone have been reported from nearby Alamitos Bay I Heish and Winter, 1954). The polychaete Capitella capitata was found at four stations (5, 6, 8, and 9) and was the most abundant animal taken (269 specimens). Several individuals of this species were incu- bating eggs at the time of collection. Capitella capitata and S'omlhis suecinea were two of the forms used by Filice (1954) as indicators of marginal zones of pollution. ■ & FIGURE 5. Lower San Gabriel River, looking southwest towards the Pacific Coast Highway (Alt. 101) bridge, the site of the dike during the dredging operations in the fall of 1952. Sta- tion 8 is located in the center foreground. Conduit in the left foreground connects with the tributary of the river (Figure 1, right branch). Photograph by the author, July 7, 1954. Ii() CALIFORNIA PISB AND GAME DISCUSSION The substratum of Lower Sau Gabriel River was completely devoid of animals al all stations sampled on May 2, 1952. At this time it was Mark in color, with either a sulfide or petroleum odor. Five animal species were presenl in the high tide horizon at some of the stations two months later (July 2, 1952). Two years later (July 15, 1954 j the substratum between the mouth and the Pacifie Coast Highway was essentially the same as observed in 1952. A few animals were present within this area in 1954, but only in small numbers. At Station 8, just beyond the Pacific Coast Highway, 474 individuals representing 11 species were taken in 1954. A polychaete worm. Cfi]>ihlla capituta, was the most common species at this station. Several C. capitata were incubating eggs, and many young meta- morphosed worms were present in the mud. This, the only species definitely established to be reproducing in the substratum of Lower San Gabriel River, was listed by Filice (1954) as an indicator species of a marginal zone of pollution. The substratum at Station 8 on July 15, L954, was black and possessed a sulfide odor, indicating that once again pollutants were accumulating on the bottom. This accummulation was particularly noticeable in the main river channel upstream from the Pacific Coast Highway, where a fine black mud layer overlaid gray mud. which is the characteristic soil for this area. Since none of the 12 species collected on July 15, 1954, was present in 1952, it is reasonable to assume that these animals migrated into Lower San Gabriel River. These animals are known to be typically estuarine forms. Nine of the 12 species had previously been reported from Alamitos Bay (Reish and Winter, 1954). All have planktonic stages during their early development, indicating that they could have migrated or drifted into San Gabriel River as larvae, possibly from Alamitos Bay. ACKNOWLEDGMENTS The field work on May 2, 1952, was done by Dr. John L. Mohr, Mr. Charles Horvath, and Mr. Howard A. Winter, University of Southern ( 'alifornia. Mr. Parke Young, California Department of Fish and Game. assisted the author with the field work on July 15, 1954. The special surveys from shore, the laboratory analyses, and the identifications of the animals (with the exception of Polydora nuchalis Woodwick, which was identified by Dr. Keith II. Woodwick I were carried out by the author. The Los Angeles County Flood Control District Office supplied the data on the excavation of Lower San Gabriel River. The author wishes to express his thanks to Mr. Robert M. Paul, California Depart- ment of Fish and Game, for his assistance during the course of this study. The author is indebted to the administration of the Allan Han- cock Foundation for the use of laboratory facilities. The specimens have I n deposited in the Allan Hancock Foundation. ECOLOGICAL STUD'S OF SAN GABRIEL KlYlli; (il SUMMARY 1. Physical, chemical, and biological studies of the water mass and bot- tom of Lower San Gabriel River, California, were made on May 2, 1952, and July 15, 1954. Special surveys of the pi I and temperature were made from shore on October 3, 1952, and November 20. 1952, and collections of the high tide horizon animals of part of the shore were made on July 2, 1952. 2. The substratum at Stations 3 to 9 and 11 to 14 on May 2, 1952, was black and possessed either a sulfide or petroleum odor. On July 15, 1!>54, the accummulation of pollutants on the bottom was partic- ularly observable at Stations 9 and 10, but odors were noted only at Station 8. 3. No living animals were observed in the bottom of Lower San Gabriel River on May 2, 1952, although several species were found in the high tide horizon on July 2, 1952. Twelve species of marine inver- tebrates were collected from the bottom on July 15, 1954. The majority of these were found at Station 8, an area which was exca- vated in the fall of 1952 under a contract with the Los Angeles County Flood Control District. There was evidence of new deposits of pollutants forming within the area of excavation. 4. Five major sources of waste discharge into Lower San Gabriel River are discussed. The liquid wastes from the Dow Chemical Company outfall sewer were the subject of a study which showed the discharge to be warm and highly acidic. Recovery of the river water to normal levels of temperature and pH took place between 150 and TOO feet downstream from this outfall. REFERENCES California Department of Public Health 1952. Lower San Gabriel River pollution survey. September 1051 to May 1952. Calif. Dept. Pub. Health, Bur. Sanitary Eng. 26 p. (Heotogra plied. ) Filiee, Francis P. 1954. An ecological survey of the Castro Creek area in San Pablo Bay. Wasmann Jour. Biol., vol. 12, no. 1, p. 1-24. Reish, Donald J., and Howard A. Winter L954. The ecology of Alamitos Bay, California, with special reference to pollu- tion. Calif. Fish and Came. vol. 40, no. 2, p. 105-121. A NEW METHOD OF ATTACHING PETERSEN DISK TAGS WITH MONOFILAMENT NYLON' JOHN E. RANDALL Department of Zoology University of Hawaii Several methods of tagging and marking have been attempted in the course of a life-history study of the eonvict surgeon fish or nianini Acanlh unis triostegus sandvicensis Streets) in the Bawaiian Islands. - The first tag tried was the Atkins tag (Rounsefell and Kask, 1945 . which \v;is fastened by tying with Ligh.1 nylon leader beneath the base of the posterior part of the dorsal fin. At the end of one month all captive fish tagged in this manner had lost their tags. Next similar tags were threaded through the bony area above the urostyle at the upper base of the caudal fin. These were retained for longer periods; however, all disappeared within six months. Dis- appointing results with such tags were reported by Fraser (1955) for smallmouth bass. Petersen disk tags, hand-made from cellulose nitrate, were then tried. Since, among metals commonly used to attach Petersen disk tags, stainless steel seemed mosi promising from a corrosion standpoint Calhoun. Pry, and Hughes, 1951), this material was chosen for initial trials. Considerable difficulty was experienced, however, in bend- ing the free ends of the wire on a struggling lish. a disadvantage clearly pointed out by these authors. An attempt was next made to devise a means of using nylon without resorting to tying knots. Four important disadvantages to the use of this synthetic for tagging when knots must be tied are: knots of nylon are prone to slip; thickness of nylon must be sacrificed to obtain tight knots; a considerable length of nylon is needed for each tying, much of which must he discarded; knot tying is wry time consuming in an operation that demands dispatch. 'the idea came to mind to melt each free end of the nylon into a little ball. This method proved successful, although there has not been sufficient time to permit any claims of exceptionally long periods of tag retention. .; name is necessary to obtain sufficient heat to melt the nylon. Heat from a very hot or even glowing object (such as a soldering iron. punk, or cigarette) does not melt the nylon rapidly enough unless the heat- producing object contacts the material. Contad often results In the Sticking of the molten nylon to the object. LSubmitted for publication March, I :>•"..">. Contribution No. 68 from the Hawaii Marim Laboratory in cooperation with the Departmenl <>t Zoologj and Entomology, i ni- \ ersity of Hawaii. 2This species does nol occur in California^ waters. However, methods used en one species are often applicable t" others, which may be far removed both geographi- cally ami by relationship. The findings contained in this article may therefore b( expected t" be of significance t" fisheries workers both in California ana elsewhere. — Editor I 03 i (i4 CALIFORNIA PISH AND GAME The best flame-produeing device found to date for tagging is the Ronson Windlite cigarette lighter. The perforated collar at the top of this lighter is more restricted than that of other windproof lighters, and the name dues not flicker as badly in the wind. Jet pipe lighters were tried, hut these blew out too readily. A small acetylene torch has been used with success, but is not as convenient as a lighter. The diameter of the monofilament nylon used measures 0.035 inches. This is sufficiently heavy to avoid the necessity of threading the strand through the back of the fish with a needle. One end of the nylon is melted into a ball and the first disk threaded in place. A dissecting needle is run through the back of the fish below the center of the dorsal fin just above the vertebral column. The dissecting needle should be drawn back and forth several times to clear the hole. The remaining free end of the nylon, which is cut on an angle to form a point, is inserted through the hole, and the second disk put in place. The flame is first used to cut off any excess length of nylon (thus eliminating the need for some cutting instrument such as scissors) and then to melt the end into a knob. The second disk serves as a natural shield against burning the epidermis of the fish during the melting process. The molten nylon requires about 10 seconds to set hard in air. If a fish is released before the nylon sets, the tags may be lost due to sudden flexure of the body of the fish. Setting may be hastened by immersing the newly-tagged fish in a bucket of sea-water while holding the second disk against the side of the body; however, this causes a further loss of tensile strength of the nylon (see below). It is important that a good-sized knob be formed, preferably two to three times the diameter of the nylon filament. If only slightly larger than the hole in the disk, the knob may be forced through the hole. Also, allowance should be made for possible attrition of the knob against rocks or coral. In order to provide for growth, space is left between each knob and adjacent disk. Approximately 3 mm. is needed on each side for growth of small adult manini (which are about 100 to 110 mm. in standard length). Surgeon fishes have compressed bodies (maximum width contained about 1.7 times in head length) and lend themselves well to Petersen disk tagging. A concrete tank at the Hawaii Marine Laboratory, which measures 34.7 feet by 10.8 feet and is an average 3.9 feet in depth, was made available for testing this method of attaching disk tags to manini. This fish grazes constantly during the day on filamentous algae. In view of the limited amount of substrate for algal growth, only 10 fish were placed in the tank. These ranged from 70 to 96 mm. in standard length. On August 6, 1953, four were tagged, three by using a monofilament nylon and one by stainless steel wire. Seven weeks later all of the fish were caught and measured. The six untagged fish, which had a mean standard length of 86.3 mm., had grown an average of 6.6 mm. The three tagged with nylon (mean standard length 84.4 mm.) grew an average of 7.7 mm. The 93 mm. fish whose disks were attached with staiidess steel wire added a smaller increment of growth than any of the other fish, only 2.5 mm. Although these data are insufficient for definite conclusions, it seems apparent that surgeon fish tagged with Petersen disk tags fastened with inonofilamenl nylon are capable of normal growth. PETERSEN DISK TAG ATTACHMENT 65 Heavy mortality of captive fish ensued during winter months, possibly because of turbid water Hollowing storms or lack of algae in the tank, one of the fish which survived 11 months, until -Inly, when the tank was needed for other purposes, still retained its nylon fastened disks. It was noted that the flesh around the hole pierced by the nylon strand was almost in contact with the nylon. There was no evidence of deterioration of the nylon. IJefore the Ronson Windlite lighter was used for tagging, working with a flame was troublesome in waters off Oahu exposed to the strong winds of the Kaiwi Channel (Molokai Channel). Personnel of the Division of Fish and (ianie. Territory of Hawaii, upon the suggestion of Mr. Kenji I«]go, resorted to crimping brass (bronze would probably be superior to brass) or stainless steel leader sleeve on the free ends. Such tags have held on field-tagged fish as long as six months. It would seem that corrosion of the metal would not be as serious at the ends of the nylon as it would be if it passed through the back of the fish, since the metal is not subjed to stresses of bending or twisting at the former location. Nevertheless, given enough time, corrosion may result iii a loosening of the metal tab from the nylon. Tests were run to compare the strength of monofilament nylon when knotted, when a metal sleeve was crimped at the ends, and when the ends were melted into knobs. Nylon of 0.035-inch diameter (rated 60- pound test) was used. When knotted with two half hitches, the nylon broke at the knot under the stress of 24 to 26 pounds dead weight. When a one-eighth-inch length of brass leader sleeve, one-sixteenth inch in outside diameter, was strongly crimped at the ends, the nylon pulled out of the metal sleeves at forces of from 16.60 to 21.58 pounds dead weight (five trials). When the ends of a nylon filament were melted to 2-mm. knobs which were allowed to set in air. 9.08 to 11.23 pounds of dead weight caused breakage at the base of a knob (five trials). When tests of tensile strength were made on nylon with knobs which had been cooled in w^ater immediately upon being formed by melting, the breaking occurred under a strain of about half this weight. Although it is evident that a considerable loss of strength occurs from heating, it should be emphasized that the strength of the nylon which passes through the body of the fish and the holes in the disks is unimpaired. As long as growth pressure is not brought to bear against the disks, it is unlikely that a force of 10 pounds could be experienced against a knob on a fish which does not exceed a half pound in weight. Also, the nylon would probably tear through the flesh of a surgeon fish before such a force could be exerted. However, should greater strength be desired, heavier nylon could be used. Heavier plastic disks would then become necessary as well. A force of 17.6 pounds was sufficient to cause craeking at the hole in the center of a 0.036-ineh thick cellulose acetate disk when it was supported I'nmi the peripheral one-sixteenth inch of its one-half-ineh diameter surface. Since the experimental work demonstrated no obvious fault in the method, held tagging was begun. Vernon E. Brock, Yoshio Yamaguchi, and Carl Al. Nemoto of the Division of Pish and Came. Territory of Hawaii, provided valuable assistance in tagging operations. 66 CALIFORNIA PISH AND GAME FIGURE 1. Petersen disk tag used in tagging surgeon fish in the Hawaiian Islands. The ends of the monofilament nylon connecting the two disks have been melted into knobs. The heating caused a blackening of the one knob which is visible. The disks (Figure 1) are laminated cellulose acetate (the manufac- turer much preferred to work with this material rather than cellulose nitrate because of the fire hazard associated with the latter), 0.036 inches in thickness at the center and 0.045 inches at the edge, and one-half inch in diameter. The O.O.'lo-inch monofilament nylon fits snugly in the hole in the center of each disk. As may be noted, the tag number appears on the inside of the disks. This is advantageous, since in Hawaiian waters algae cover the outside of the tag after immersion of a month or more, but do not accumulate on the inside. Some of the algae are calcareous and difficult to remove. PETERSEN DISK TAG ATTACHMENT 61 Most of the fish have been tagged from commercial trapfishing vessels operating Prom Kewalo Basin, Honolulu, since July 6, 1954, when extensive tagging began, a total of 1,202 tnanini bave been tagged, and to date there have been 265 recoveries-. Some fish have been recovered which had been at liberty for six and one-half months. Most of the Lagged fish have been taken in traps and are broughl to porl alive in wells on the vessels. This has afforded an opportunity for re-release. Twenty-three tagged fish have been caughl a second time, and three of these have been taken a third time. The tagging wounds of most of the recovered fish are small, rarely exceeding 2 mm. in diameter. When the wounds are larger, the fish generally show evidence of lone- sojourn in traps: bacterial and fungus infections which cause eroding of the fins, and raw, abraded areas on the snout and forehead. No tags were seen in the process of migrating up through the back of the fish. It is believed that monofilament nylon, when used without knotting, will prove to be superior to metal pins or wire for attaching Petersen disk tags to fish. Nylon appears to have the following distinct ad- vantages over metal in general: no obvious deterioration due to corro- sion or galvanic action, nontoxicity, and greater flexibility and softness. REFERENCES Calhoun, A. J. 1953. Aquarium tests of tans on striped bass. Calif. Fish and (lame. vol. •">'••, no. 2, p. 209-218. Calhoun, A. J.. D. II. Fry. Jr., and E. P. Hughes 1951. Plastic deterioration and metal corrosion in Petersen disk tish tags. Calif. Fish and Game, vol. 37, no. 3, p. 301-314. Forrester, C. It., and K. S. Ketchen 1955. The resistance to salt water corrosion of various types of metal wire used in the tagging of flatfish. Fish. lies. Bd. Canada, .lour., vol. 12. no. L, p. 134-142. Fraser, J. M. 1 !)."). The sinallmouth bass fishery of South Bay, Lake Huron. Fish. lies. Bd. Canada. Jour., vol. 12, no. 1, p. 147-177. Rounsefell, G. A., and J. L. Kask L945. How to mark fish. Amer. Fish. Soc, Trans., vol. 7::. p. 320-363. Skinner, J. E., and A. .1. Calhoun L954. Field tests of stainless steel and tantalum wire with disk tags on striped bass. Calif. Fish and Game, vol. to, no. 3, p. 323-328. Young, P. II.. J. W. Schott, and It. I >. Collyer L953. The use of monofilament nylon for attaching Petersen disk tish tags. Calif. Fish and Game, vol. 39, no. 4. p. 445-462. REARING LARVAL SCOMBRID FISHES IN SHIPBOARD AQUARIA1 HAROLD B. CLEMENS Marine Fisheries Branch California Department of Fish and Game INTRODUCTION The scombrid group of fishes includes many species which are of considerable economic importance and several others which have an milapped economic potential. The Eastern Pacific fishery for yellow- fin tuna. Neothunnus macropterus, and oceanic skipjack. Katsuwonus pelamis, for example, represents one of the most valuable marine re- sources of modern times. Each year this fishery brings new wealth to the State of California and provides gainful employment for many thousands of individuals. This fishery and the fish supporting it are being studied by several governmental agencies in an effort to develop methods and techniques to maintain the fishery so as to provide the highest possible economic yield. Such studies require detailed information about the biology of the fishes throughout their entire lives. Extremely little is known about the distribution, growth, and behavior of larval and postlarval scom- brids, and methods to obtain this much needed information are still in developmental stages. Sine- 1950, the author has had an opportunity to gain information on the young stages of scombrid life history. On various cruises off Central and South America and the Galapagos Islands, several months of each year have been devoted to studies of tunas and their close rela- tives. During each cruise an attempt has been made to estimate the magnitude of spawning areas by obtaining larval specimens. Extensive collections of recently hatched scombrids from the waters of Central America resulted in plans for an attempt to rear them in aquaria during a scheduled cruise of the X. B. Scofield in January and February, 1955. in the belief that a successful efforl would offer an opportunity to observe the behavior of the postlarval fish and to Learn something about their growth rates. This paper presents the results of the initial attempt to rear young tuna-like fishes in aquaria and describes the techniques developed. It is hoped thai these preliminary experiments will furnish a basis for further experiments by fisheries biologists and eventually will enable them to raise these fast-swimming fishes to considerable size and age. - 1 Siilunil titl for publication August, I '.i r, .", . < 69 » CALIFORNIA PISH AND GAME EQUIPMENT USED The two aquaria used in this experiment measured 36| x 24 x 17 inches and were solidly constructed, on three sides and the bottom, of two-inch by eight-inch redwood slabs. One side was enclosed with one- balf-inch plate glass to serve as an observation window. A piece of one-quarter-inch marine plywood was secured across the top to prevent water and fish from splashing out in rough weather. Specimens were pnl in the tank through a nine-inch-square hole cu1 in the plywood top. Each aquarium was supplied with constantly circulating sea water, which entered a1 the bottom through a one-quarter-inch hose and drained from an overflow pipe near the top. A 100-watl bulb was sus- pended above the opening in each lank and left burning at night, enabling the fisli to see and thus avoid the aquarium sides. Other equipmenl included: a small glass aquarium 20x10x14 inches; a standard, Long-handled dipnel with three-millimeter mesh in the bag; an eight-inch, square, short-handled dipnet with three-millimeter mesh; and a night light consisting of a 1,500-watt bulb, pins reflector. COLLECTING METHOD At night, when the vessel was drifting or anchored in an area known to have produced postlarval scombrids, the night light was suspended over the stern approximately three feet above the water. Various small fishes attracted to the surface by this light were easily captured with the long-handled dipnet. The net contents were then carefully emptied into the small glass aquarium, which had been half filled with fresh sea water and conveniently located on the stern of the N. B. Scofield. All of the fish captured in each dipnet sweep could then be clearly observed with the aid of a 150-watt bulb located on the opposite side of the aquarium. The larval scombrids of paramount interest, yellowfin tuna and oceanic skipjack, are difficull to distinguish, by such gross observation, from several closely related species. The delicate nature of larval scombrids precludes a careful microscopic examination; however, sepa- ration of yellowfin tuna and black skipjack (Euthynnus) from other scombrid larvae can be accomplished with little chance for error. Ac- cording to Schaefer and Marr (1947) and Mead (1951) only the larvae of yellowfin tuna and black skipjack have a solidly pigmented spinous dorsal fin. Although it has been found that larval bonito (Sarda) also have a solidly pigmented first doral fin, they can he distinguished from both I'] ii Ih a n ii us and Neothunnus by their black ventral fins. For the purpose of this experiment it was felt that either black skipjack or yellowfin tuna would serve equally satisfactorily. As a result, one had only to look for a tuna-like larva with a black first dorsal and clear ventrals. When such a fish was recognized it was recaptured with a small dipnet, immediately placed in a wide-mouth gallon jar filled will) fresh sea water, and then quickly transferred into one of the large aquaria. The remaining fish were removed from the glass aquarium, and either preserved <>r placed in the other large aquarium. The gallon jar was refilled and the process repeated. Several precautions were necessary: only one sweep of the dipnet could be made at a time, since the pressure of too many fish in the net BEARING LARVAL SCOMBRIDS I 1 resulted in fatal injuries. The cupped palm of one hand was placed on the bottom of the bag when depositing each dipnel Hull of fish into the small aquarium. The bay could then be deftly flipped wrong side ou1 and the specimens gently washed into the water, thus insuring thai the opercular spines on small scombrids were not entangled in the mesh — a fatal mishap. Other unrelated species were nut placed in the same tank, for very little is known concerning the predaceous habits of im- mature fishes, lu all operations maximum speed ;md care were used, and a minimum of handling employed. Even though extreme caution was exercised, only one-third of the larvae captured survived longer than 24 hours. FIRST FIELD TRIAL During the evening of -January 20th, at latitude 12° 34' N., longti- tude 89° 50' W., between 6 p.m. and 12.30 a.m. approximately 280 separate dipnet sweeps produced eight scombrid larvae with black first dorsals and clear ventrals averaging one inch in total length. After having been gently washed from the net into the glass aquarium, two of these "tuna" swam about at great speed in a very erratic manner. repeatedly bumping their noses on the sides and bottom of the tank. Death resulted in a very short time (similar behavior has been noted in adult tuna; some lie quietly after being caught while others main- tain a powerful frantic vibration until their gills hemorrhage, with death resulting). The remaining six small "tuna" showed oo unusual behavior and were placed in the large aquarium. Unfortunately, three died within 24 hours, probably as a result of injuries received during capture. The three remaining fish swam aimlessly about the large aquarium, making no effort to school, and refused various kinds of food offered throughout the day and night. The food offered included: living plank- tonic organisms, ground flesh of anchovetas (Cetengrairiis mi/sticetus . yellowfin tuna, oceanic skipjack, and dolphinfish (Coryphaena hip- /ninis). particles of coagulated fish blood, and dolphinfish eggs. These "tuna"' showed only mild interest in each type of nonliving food offered, but paid particular attention to several of the fast-swimming planktonic organisms. It is thought that they were unable to recognize the particles offered as being edible. A heavy sea during the following two days caused water to splash around in the aquarium and the three larvae had a difficult time avoid- ing the sides. By the morning of January 23d it was obvious that they were starving: their bodies had become shriveled and emaciated, caus- ing their heads to appear greatly enlarged. That afternoon at 2 p.m. all three specimens were dead. The battering they received iu the aquarium, as a result of the rough weather, probably hastened death by 24 hours. In contrast, the postlarvae of several other species, captured at the same time as the "tuna" and placed in the other large aquarium, were doing nicely. This group, including dolphinfish (Coryphaena . jacks \(' . .". 25 . 0 26.5 0.24 fl6.5 *25 . 5 27.0 0.18 17.5 25.5 27.0 0.25 22 . 0 26.5 28.0 0.25 27.0 28.0 0.26 28.0 29.5 0.31 28.0 30.0 0.30 30.0 31.0 0.44 31.0 32.0 0.38 32.0 33.0 0.42 34.5 36.0 0.56 35.0 37.0 0.57 37.0 39.0 0.60 37 . 5 40.0 0.57 173 hours of growth *48.0 51.0 1.51 48.0 50.0 1.67 52.0 55.0 1.91 197 hours of growth 54.0 58.0 2.37 54 . 0 58.0 2.10 *55 . 0 58.0 1.94 246 hours of growth 59.0 63.0 2.61 59.0 63.0 2.74 *6.-) . 0 69.0 3.75 71.5 75.0 4.72 319 hours of growth t54 . 0 47.5 * Photograph (Figure 1). t Photograph (Figure 2). RE \i:im; LARVAL SCOMBRIDS i i Twenty-three of 34 fish captured for the second trial died within ■J4 hours, 1" From handling injuries and 13 because of their erratic natures. One specimen, no1 included in Table 1. mysteriously broke its upper jaw a day after capture. It was unable to Peed actively, bu1 sur- vived in a stunted condition for 133 hours, at which time its standard length was 34.0 nun. and its weighl 0.44 grams. Three fish survived an average of 17.'! hours. Their average standard Length was 4!).:! mm. and their weighl 1.70 grains. Weight had increased approximately five times in seven days. Three of the remaining seven survived for 197 hours. These had an average standard length of 54.3 mm. and a weighl of 2.14 grams. "Weight had increased six times in eight days. The four fish which grew for a total of 246 hours averaged 63.6 mm. in standard length and 3.46 grams in weight. Weight had increased 11 times in 10 days. During the entire 10-day period, length had increased approxi- mately 1.4 times. The growth data in Tables 1 and 2 probably more nearly represent a minimum in nature. More than half the total observed weight in- crease occurred during the last three days, during two of which the fish apparently suffered from lack of oxygen and food consumption dropped off. SCHOOLING AND SWIMMING OBSERVATIONS specimens of Euthynnus, of the size captured, have never been observed by the author schooled in the ocean under a night light, but as soon as four or more were placed in an aquarium under a light, they formed a tight, orderly school Apparently, if sufficient numbers congre- gate and are strong enough to remain grouped, a school will be formed. In the confines of an aquarium, in which strong water movements and large areas are not involved, il is relatively easy for these juveniles to school. Bullis (1955) reported schooling behavior of E. alletteratus under a night light in the offshore waters of the Gulf of Mexico. He noted two separate schools of approximately 200 fish each, ranging in size from 20 to 31 mm., fork length. Euthynnus larger than 45 mm. in standard length do not appear near the surface under a night light but are sometimes found in stomachs of larger predators, such as yellowfin tuna and rainbow runners, Elagatis bipinnulatus, captured on hook and line during daylight hours. Swimming was accomplished by a quivering of the body between the insertion of the first dorsal fin and the tip of the caudal fin. One might best describe these motions by saying that the entire body behind the opercle is a single, quivering, locomotive appendage which serves to push the head through the water. By comparison, young dolphin- fish swam with an undulating motion of the trunk and tail. Etithynnus larvae swam constantly during both day and night never resting. Periodically one fish would leave the school, examine a small panicle. and rejoin immediately to continue on a tireless circuit. The firsl dorsal fin lay in a groove in the back while swimming, resulting in a stream- lined appearance. When a fish beeai ixcited or slowed down to exam- ine food particles, the first dorsal fin was erected. Then' was no evi- dence of a school leader; all fish changed position 1»\ frequenl regroup- ing. There was, however, a slighl tendency for lamer fish to stay at the head of the school. 7s C M.II'dKMA PISH A\|) (i.\ \l i; OBSERVATIONS ON AUXIS AND SCOMBEROMORUS LARVAE The larval scombrids most frequently captured under a night lighl in the tropical eastern Pacific are frigate mackerel. These fish, some- times called "bullets" by tuna fishermen, are more numerous and widely distributed than Euthynnus larvae. In areas where larvae of both frigate mackerel and Euthynnus occur, in the samples taken under the lighl the former outnumber the latter by an estimated 300 to 1. During the evening of .January 20th, five postlarval Auxis were placed in the aquarium for observation. Three died several hours later from injuries received in handling. Two, 20 and :'>() mm. in total length, survived for six days. The larger of the two leaped oul of the aquarium one evening and was badly decomposed when discovered the next day. It had "tiiwii an estimated 46 mm. during the six days. The remaining specimen was fatally wounded by a 35-mm., transparent, larval blenny that darted up from the bottom of the tank and bit out a chunk of flesh immediately posterior to the second dorsal fin. This frigate mack- erel had grown approximately 40 mm. during its six days in captivity. These measurements indicate a more rapid rate of growth for Auxis than for Euthynnus. During the evening of February 5th, at latitude 08° 06' N., longitude 79° 06' W., 14 postlarval sierra mackerel. Scomberomorus sierra, rang- ing from 12 to 22 mm. (average 15 mm.) in standard length, were placed in the aquarium. Five died several hours later from handling injuries, and seven starved to death within a few days. Two, however, survived for 13 days, during which they grew approximate 1\- :!(i mm. (Table 2 and Figure 2). FIGURE 2. Postlarval Scomberomorus sierra, Illustrating growth during 13 days of captivity. These fish are, respectively, 16.5 and 54.0 mm. in standard length. Photograph by Jack Schott. BEARING LARVAL SCOMBRIDS 79 ACKNOWLEDGMENTS Many individuals cooperated wholeheartedly in making this experi- ment possible. I would like to extend my thanks and appreciation to .Messrs. Kenneth NTorris and Jack Sehott for the loan of aquaria; to the captain and hardworking crew of the N. B. Scofield for assisting w i h nighl li'dit collecting, and especially to the engineers, who also maintained the aquaria in good working order; to Mr. Lee Tebo, who assisted me and shouldered the lion's share of the work during the Las1 half of the cruise; and to Mr. Michael Angot, a visiting biologist from France, who was always willing to lend a hand in all operations. REFERENCES Bullis, Harvej R., Jr. L955. Observation on schooling juvenile tuna, Euthynnus alletteratus, in the Gulf of Mexico. Copcia, no. 2, p. 153. Godsil, H. C. 1054. A descriptive study of certain tuna-like fishes. Calif. Dept. Fish and Game, Fish Bull. !>7, 185 p. Mead, Giles W. 1951. Postlarval Neothunnus macropterus, Auxis thazard and Euthynnus lineatus from the Pacific coast of Central America. U. S. Fish and Wildl. Serv., Fish Bull., vol. 5i>. no. <;:;, p. 121-127. Schaefer, Milner !'»., and John C. Marr L948. Contributions to the biology of the Pacific tunas. U. S. Fish and Wildl. Serv., Fish Pull., vol. 51, no. 44, p. 1ST -206. NOTE BLUE-WINGED TEAL IN DEL NORTE COUNTY, CALIFORNIA In reviewing the literature, we find no record of blue-winged teal (Anas discors) in the extreme northwestern corner of California. The northwesternmost observation of this species in California is one re- ported two and one-half miles north of Areata, Humboldt County (Clay, 1!):}!)). Wooten, while conducting a survey of nesting waterfowl in the vicinity of lakes Earl and Talawa, Del Norte County, on May 14, 1953, observed a female teal with a brood of at least five yonng on a small pond on the Talawa (inn Club approximately one mile north of the channel connecting' the two lakes. In the same pond a male blue-winged teal in breeding plumage was flushed ; the bird circled the area and re- fused to leave. Wooten assumed that the female teal was the mate to the male, and therefore represented a breeding record for blue-winged teal in this coastal area. On June 10, 1954, the authors visited the same area, and a blue- winged teal male in breeding plumage was flushed from the small 2-acre pond on which Wooten had seen blue-winged teal the year before. This male demonstrated behaviorism similar to blue-winged teal flushed by the senior author from breeding areas in the small ponds of the chan- neled scablands of eastern Washington. We were unable to flush ;i female, hut the male continued to return to this pond after being flushed. Another male blue-winged teal (or possibly the same bird I was seen on Lake Talawa the same day. The pond on which the birds were seen is very shallow, but perma- nent. American three-square bulrush (Scirpus americanus) and rush (Juncus) were the dominant plants that extended to the open water. Rush, sedge [Carer sp. i, and forbs constituted the major plants in the /one that extends to higher ground, where grasses dominated. Small willow trees bordered the pond on the c;ist side and yellow water lily {Nymphaea polysepala) grew in the deeper water. Sand dunes stabi- lized with grasses extend westward to the ocean. Cattle utilize this grassland. In many respects this area is similar to those used by nesting blue- winged teal observed in eastern Washington. <>n June 7. 1955, the area was visited again, hut no blue-winged teal were seen. There are several potholes in this area, however, so we could have missed flushing the birds. Water levels were very low this spring, in contrast with the other two years. REFERENCE Clay, CI. 1939. While throated sparrow coincidence and other notes. Condor, vol. It. no. 3, 1.. 121. Charles /•'. Yocom, Humboldt State College, Vrcata, and William I. Wooten. for- merly Came Management Vgent, Eureka, California, September, in',.',. | 81 ) REVIEWS Conserving Nafural Resources: Principles and Practice in a Democracy l'.\ Shirley W. Allen; McGraw-Hill Book Company, Inc., New York, 1955; is • 347 p., 169 figs. $5.50. The title of this book implies that there is a difference between a democracy and other forms of governmenl in the methods used in the conservation of natural re- sources. The democratic way is described as I > < • i 1 1 n- somewhere between the cutout .-mil get "in policy of the old lumber barons and the Tennessee Valley Authority. The genera] tone of the book is. however, conservative and indicates thai the preferable approach is that of private exploit.it ion. This is a text book — a good one. but not any better than many Others. It is written by a distinguished individual, which gives it some additional weight. If you are a teacher, then you will he quite interested in reading it and possibly, depending upon your approach, using it as a text. If you are a student using it as a text, you will probably sell it when the course is over. The whole field of natural resources is covered in a rather unimaginative but certainly adequate fashion. A total of 169 illustrations is used, most of them being photographs. Again, they are adequate, but not imaginative. The problem appears to be one of format. Here is a greal teacher writing from years of experience hut somehow missing the idea that a hook, particularly an introduction to ;i field as important as this, should inspire, not bore, students. There are seven chapters, including an excellent Introduction and a thought- provoking chapter on Human Powers as Natural Resources. The others cover the fields of Soil Conservation: Water; Forests, Grazing and Recreation; Wild animal Resources (including fish) : and .Mineral Resources. The qualitj of this hook is of the highest in physical materials, such as binding and paper, as well as in intellectual materials. The feeling persists, however, that as an introductory text it would he very ably resisted by students. ./. Bruce Kimsey, California Department of Fish ami Game. Soil By <;. V. Jacks; Philosophical Library, New York. L954; ix + 221 p.; 10 pis. $5. The preface of this little book sialcs its purpose as being that of u i \ i 1 1 1; inter- ested persons an insighl into the new science of soil management. This it proceeds to do in ;i most informal, brief, and interesting manner. For instance, such an extensive subject as soil chemistry is disposed of in about 22 well written, straight- forward, pages. The only prerequisite to understanding is relaxed interest and perhaps high school chemistry. It is written and printed in Great Britain. Because of this, many examples will be rather obscure to American readers, since they are largely drawn from European sources. The principles, however, are the same ami. in a few Instances, North Amer- ican situations are used for illustration. A pertinent bibliography of tin citations is included. .Main of the references are not readily available to American readers, ho\ve\ er. In the chapter on soil erosion the interesting idea is offered that soil erosion max be regarded by posterity as one of the greatesl blessings European civilization his given the world. Milt of context this appears ridiculous, but the reason for the remark is quite sensible. Agricultural revolutions tend to he long, drawn out affairs and they need powerful stimuli to sel them in motion. Soil erosion has been such a stimulus. This reviewer recommends this I k to anyone with an interesl in soil conserva- tion, providing they understand that it is an erudite introduction to the science written for tin. educated layman and not a technical handbook. - I C MjIFORNIA FISH AM) GAME In comparison with books of ;i similar materia] quality, the cosi of (Ins volume appears to be somewhal high. •/. Bruce Kimsey, California Department of Fish and Game. Aspects of Deep Sea Biology By X. B. Marshall; Philosophical Library, In.-.. New York. i'.ir,4; 380 p., 103 figs. + 5 col. plates; illustrated by ol.ua .Marshall, sld. Here is a book that is interesting and very worthwhile for both the student and the practicing fisheries worker. Those of us engaged in marine research know only too well the inadequacy of man's current knowledge of the physical and biological aspects of the ocean depths. However, each day brings new discoveries, and if we consider the relatively short lime which has elapsed since the first studies of deep sen biology were made and realize the great technical problems involved, if is obvious that we have come a long way in our understanding of the deep sea and its inhabitants. The author, a British worker, lias compiled in fairly orderly fashion what is essen- tially an inventory of knowledge on certain aspects of deep sea biology. There is particular emphasis on those subjects (adaptations of deep sea fishes and deep scattering layer organisms) on which he has done original research. Approximately the first third of the book is devoted to an historical account of the growth of deep sea biology, the methods and techniques of studying the sea and collecting data and specimens, and a rather brief description of the physical environment of the depths. The remaining chapters deal with the organisms themselves, their structures and modes of life, and the patterns of adaptations which make them uniquely suited to their environment. Obviously, in a single volume covering a subject as broad as this a great many details will be slighted and many topics, of vital importance, will not he mentioned. However, the information presented and the extensive bibliographies following each chapter expose the reader to a wealth of material and afford him the opportunity to delve more deeply into those facets of the field in which he may be particularly interested. The book is generally well written and easily understood and is amply illustrated in black and white and color. The five color plates which have obviously contributed to the rather high cost of the book .-ire indeed beautiful. — David C. Joseph, Cali- fornia Department of Fish and (lame Modern Spearfishing By Vane Ivanovic; A. S. Barnes and Co., New York, 1955; ix + 203 p., If) photos and <»!( line drawings. $3.75. This is one of the better books on diving which the reviewer has read. The main subject is spearfishing, but there is good coverage of diving in general. It should make interesting reading for both the novice and the expert. The author makes one common mistake. In singling out a few divers and naming them the best in a given area, he assumes that the best are always those who attain I hi' most publicity. There are many in tliis sport, as in any other, who go about their favorite diversion quietly, sans publicity. Many of these are equal or superior lo those whose names and pictures make the magazines. In fact, the reviewer knows many divers who are as reticent above water as they are below. The technical chapters of the book on "Breathing underwater". "The human body and pressure", etc., are generally accurate and complete. In the chapter on fishes the author does show a lack of knowledge, but as be makes no claims to being a biologist, his mistakes in terminology, spelling, and handling of nomenclature can easily be forgiven. All in all the 1 k can be recommended for both the vicarious and the active diver. Its style and light vein make it good reading. John G. Carlisle, Jr., Cali- fornia Department of Fish ami Game. The Underwater Naturalist By Pierre de Lat.il (translated from the French by Edward Fitzgerald); Hough- ton Mifflin Company, Boston, 1955; -To- p., illus. with photos and line draw- ings by Hubert Williams. $3.50. REVIEWS 85 (tin' of the tirsi impressions received from iliis boob was of its complete provin- cialism; the author apparentlj has no knowledge of early diving developments out- side of France. In the early and mid-1930's there was also a band of pioneers in Southern California, who firsl used Japanese pearl diving goggles, then made their own face plates, and later were able to buy Japanese face plates. They dove for abalones and lobsters and speared fish with Hawaiian-type spear guns — and they dove for the sheer joy of diving, without publicity. The reviewer was one of this group and can vouch for the dates. The reviewer experimented as a boy during a two-year stay in Europe, diving with swimming goggles as early as 1928-1930 near ('amies, mi the French Mediter- ranean coast; there must have been others. The author could have said that diving became widely popular from the impetus it received from this area in France in the late I930's. It is good that the author dues qoI call himself a biologist, but even for a natural- ist he shows a singular lack of knowledge of biology and scientific nomenclature. For example, he is amazed that systematists have made some changes in classifica- tion and fiish nomenclature after dO years. I doubt if the fisheries biologist will .are to wade through the chapters on fishes which take up most of the book. — ■ John G. Carlisle, Jr.. California Department of Fish and Game. Pacific Salmons, Trouts, and Fresh Water Fishes By C. E. "Quill" Gordon. Manuscript Press, Portland, Oregon, 1954; 70 p. $1.50. This booklet of TO closely printed pages consists of a series of accounts of the individual species of both introduced and native freshwater and anadromous fishes of the Pacific Coast. According to the author, the information was c idled not so much for the benefit of the ichthyologist or to "delight the haughty'* as to enrich "the fishing pleasures of the humble" through increased general knowledge and to extend "a welcome * * * to the uninitiated." It is not an easy task to sift and comb data scattered throughout numerous bulle- tins and technical papers and present them in popular yet accurate form. The author has succeeded in considerable measure, although the professional worker will no doubt raise an eyebrow now and then. The choice of some adjectives — such as "restless'" — to describe the qualities of the various species might be questioned, and occasional omissions and inaccuracies occur. For example, the author states (page 7i that "Columbia spawned chinook not only [provide the bulk of the multimillion harvest of the offshore fisheries of Alaska ami British Columbia, but these fish also range south to support the California salmon fisheries as well." Thus, tin1 enormous contribution made by the runs of the Sacramento San Joaquin river system is ignored. One page 28. in saying that "The golden trout are found in the high mountain waters of the 10,000 foot elevations in the Sierra Nevada of California", the author perpetuates a rather widespread fallacy. Actually, in their native habitat golden trout are found at elevations down to ('(.".(III feet or less. Although on page 49 he states that "All the spiny-ray fishes except the yellow perch are nest builders that defend their eggs and young during the most critical period of the life cycle." be later (page <'><'l correct ly notes that the Sacramento perch constitutes another exception. « in the latter page he says that "The Sacramento perch is a spirited game fish that takes the hook readily * * *." Californian fisheries managers, who have at- tempted to further the Sacramento perch as a game fish, have been distressed by its reluctance to take a hook during most of the year. Throughout his accounts, the author interweaves commentary on the effects of man's activities on the various species. He also comments on their management, and calls at lent ion to the possibilities of greater utilization for food of some of the led "roughfish". No references are included, but the author directs the reader to the state fish and game departments for more detailed and localized information, and notes that usu- ally literature is available from them on request. He a No wiselj advises the angler to familiarize himself with the policies and programs of these agencies. — Leo Shapovalov, California Department of Fish ami Game. 86 i \l.ll(H;.\i.\ PISH AM) GAME A Manual of ihe Dragonflies of North America (Anisopiera) Bj James G. Needham and Minter J. Westfall, Jr., [Tniversitj of California Press, Berkeley, 1955; xii + 615 p., illus. $12.50. Everj once in a while :i book appears thai has been heralded for a long time by persistent rumors of its preparation. This is such a book and ii was certainly worth waiting for. The authors have produced what will undoubtedly prove to be ;i classic This reviewer, nol being an authority <>n the taxonomy of the Anisoptera, cannot criticallj evaluate thai phase of the work. However, as a fisheries hiologisl with an interest in aquatic entomology he must give this look Ins wholehearted recom- mcmlat ion. The manual is divided into two parts. The first consists of an introduction to the natural history of dragonflies, a description of methods of study and collection. and a brief section on procedure, in which the reader will find material designed to make the use of part two easier. The importanl anatomical characters used in keying out adults and nymphs are clearly illustrated in the introductory section by photographs, and in the instance of wing venation by line drawings. Careful study of this section should make the use of the keys pleasurable. Part two I about 88 percent of the 1 k) covers systematic classification and contains keys to families, genera, and. where possible, to species. Both adults and nymphs are treated. The keys to nymphs are of particular value to fisheries biologists. The biology of each family, genus, and species is usually discussed when such in- formation is available. This includes environmental notes, information on reproduc- tion and transformation, and other pertinent material. Tables summarize taxonomic characters of families and subfamilies, genera, and species. In the case of each group these characters are given for both adults and nymphs. The complete treatment of the nymphs is unusually valuable and is a phase long neglected. Keys to nymphs are not unique, but this is the first volume to be seen by this reviewer that treats the subject completely. The quality of this book is excellent. The photographs are clear and demon- strate beautifully what they are meant to demonstrate. The line drawings are precise and without the superfluity of unnecessary applique stippling or shading. The illustrations of wing venation, a most importanl key character for the adults, are as beautifully simple as the original wing. The publisher is to be complimented upon a tine job of printing and binding. This volume is recommended without reservation to anyone interested in dragon- Hies. •/. Bruce Kimsey, California Department <>i Fish mid Game. Mammals By Herbert S. Zim and Donald Hoffmeister ; Simon and Schuster. New York. 1955; L60 p.; illustrated by dames Gordon Irving, si paperbound, $1.95 cloth- bound. This addition to the Golden Nature Guide series is a good source of information for both adult and youthful outdoorsmen who are interested in identifying the mammals which may be encountered on their trips into the field. In a simple and direct style the authors have classified, described, and illustrated 218 of the 350 species of mammals found in the United States and Canada. The illustrated key to mammals in the foreparl of the 1 k groups the mammals handily for locating the descriptions and illustrations ami the index of scientific names on page 155 completes the identification. For more rapid use, an index of common names is included in I he back of t he 1 k. The illustrations are clear and the color is good on the bats and smaller mammals, rodents, etc. The illustrator did become rather bold in the use of his brush, which gives a coarse look to many of the paintings. However, if one does not criticize by Comparisons and accepts the key features, the illustrations serve their purpose — that of identification. Due to the reduction in size, the distributional maps are rather weak, but if one keeps in mind the general use to which this book will be made, they are satisfactory. This reader found only one glaring fault, and that was the confusing illustration and descripti f the mule and black-tailed deer. — George 1>. Seymour, California Department of Fish and (lame. REVIEWS -7 Bird Navigation q, (; \- i.. Matthews; Cambridge University Press, New Xork, 1955; vi + III p. $2.50. This little volume of ll!-". pages of pertinenl texl and 1~> pages of bibliographj i- ;i remarkable job of condensing the importanl facts from the major works dealing w iili this field. One has the feeling, after reading a few pages, thai here is the meal "l bird navigation and migration minus the long involved dissertations of mosl other works on the subject. [„ ,|H. tirst two chapters the author takes us through the contributions i<> the knowledge of bird navigation and migration made bj the taxonomists and field collectors. Field observation and systematic specimen collecting have played :i major pari in the mapping of birds' movements, and some of the other more involved problems relative to age, independence, high and low level flying, channelling of migrants, and other related phases. Prom ili«' above chapters he brings mil the experimental evidence of bearing and distance navigation. As an example, young storks were used. In this species, the ,,|,| and young migrate independently. The young were removed far outside their regular range for release. The cases studied gave, in general, the same conclusion ih.it the young birds contii il to migrate from the release poinl in the same direction thai their congeners follow from the trapping site This was a parallel (■ours.' Mud took them far outside their normal winter range. In Chapter •"> the author leads into ;i discussion of various homing experiments, from which verj interesting observations and conclusions were obtained. In the next chapter tin1 reality "f a complete form of navigation in birds is discussed, and manj instances are demonstrated of rapid return to their original home by banded birds. The developmenl of the theories brought forth in the earlier chapters is well covered in Chapter ■"» and shows wh.it physical features of environment are con- cerned in this navigation, as well ;is the sensory equipment needed to read to such stimuli. Various theories, such as magnetism, coriolis force, .- 1 1 1 < I pressure patterns, are discussed and rejected. The author thru discusses the extensive work done with the sun acting as ;i poinl of reference. Most of the many experiments point toward this theorj conclusively in one directional navigation. Complete navigation through maintenance of sensory contact with home is dis- cussed in various phases. Birds have acute vision, but it is doubtful that they can see any farther than we can and they .-ire. of course, limited by the earth's curva- ture. Even at 3,000 feet tin' horizon is never more than 7-"> miles away. Chemical and physical constitutents of the atmosphere and radiation are dis- carded. Succession of visual landmarks, sense id' smell, memory of outward route, anil other theories are discussed and discarded. This leads into a discussion of complete navigation by means of a "grid" derived from the earth's rotation and magnetism, which is rejected as nearly impossible. The meat of the hook follows in Chapters S and !», in which the theory of com- plete navigation bj means id' a grid derived from the sun's co-ordinates is developed. It has been so thoroughly demonstrated by a series of experiments with controlled light, that it seems to leave little douhl as to the realiU of the theory. The essential feature of the theory is the sun-arc. The structure id' the bird's eye is known to he exceptionally well developed. Ii i^ then demonstrated how the function of the eye makes use of the sun-arc hypothesis. The fixed reference point is always due south. Bearings are apparently fixed from that point by use of the bird's chronometer in whatever form this occurs. In conclusion, the primary stimuli for t Ii set of migration appear to he changes in the stm arc and day-length. \o theory of the physical basis of bird migration remains in the field except that involving the sun. Donald l>. McLean, Cnlii>/ri>i