CAUFORNIAI 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 722 Capitol Avenue 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. u VOLUME 43 APRIL, 1957 D V NUMBER 2 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 ANDY KELLY, President Los Angeles CARL F. WENTE, Commissioner WILLIAM P. ELSER, Commissioner San Francisco Son Diego WELDON L. OXLEY, Commissioner T. H. RICHARDS, JR., Commissioner Redding Sacramento SETH GORDON Director of Fish and Game CALIFORNIA FISH AND GAME Editorial Staff LEO SHAPOVALOV, Editor-in-Chief Sacramento JOHN E. FITCH, Editor for Marine Fisheries ..Terminal Island CAROL M. FERREL, Editor for Game Sacramento J. B. KIMSEY, Editor for Inland Fisheries Sacramento TABLE OF CONTENTS Page Largemouth Bass Tagging at Clear Lake, Lake County, California /. B. Kimsey 111 Survival of Precociously Mature King Salmon Male Parr {OncorJiynchus tshawytscha Juv.) After Spawning 0. II. Rohertson 119 Determining the Sex of Dressed Pheasants Milton Ilildebrand 131 Studies on the Incidence of Poultry Diseases in Wild Ducks Erling R. Quortrup, 139 M. E. Goetz, J. W. Dunsing, and Merton N. Rosen Studies on the Incidence of Poultry Diseases in Coots Merton N. Rosen, 143 Erling R. Quortrup, M. E. Goetz, and J. W. Dunsing Note Tagged Dover Sole (Microstomus pacificus) at Liberty Six Years E. A. Best 147 In Memoriam — Charles R. Clothier 148 Reviews 149 2— 49S92 (109) ERRATUM Report on the Distributioji and Abuudance of Pacific Herring (Clupea pallasi) Along the Coast of Central and Southern California, vol. 42, no. 3. On page 174, lines 10 and 11 from bottom, read "Sacramento smelt {^pirincJius thalcichthys)''' for "eulachon {TJialcichthys pacificus)". (110) LARGEMOUTH BASS TAGGING AT CLEAR LAKE, LAKE COUNTY, CALIFORNIA' J. B. KIMSEY Inland Fisheries Branch California Department of Fish and Game In June, 1953, a largemoiitli bass {Micropterus salnioides) tagging study was begun at Clear Lake, Lake County, to obtain statistics on angling and natural mortality. Such statistics are necessary for sensible angling regulations and are best obtained through tagging studies. Any migrations of the fish that might influence angler success are also indi- cated by such studies. Clear Lake (Figure 1) is a seminatural 4(),()()()-acre lake with a max- imum depth of about 50 feet. It lies in central Lake County in northern Califoriua at an elevation of 1,325 feet. The outlet is Cache Creek, a tributary of the Sacramento Kivcr. The lake level has been partially controlled since 1915 by a dam on this outlet. The ecology and fishery of Clear Lake have been described by ]\Iurphy (1951). In a study such as this that continues over an extended period many people participate and deserve acknowledgment. Almo .1. Cordone con- tributed the most in time and effort, in both the field and laboratory. Leonard 0. Pisk, David P]. Pelgen, and George W. McCammon also assisted in the field work. Leonard (). Pisk, Ed V. Dwyer, and Robert R. Bell assisted in compilation and recording of data and tag returns. METHODS Capture All fish were taken bv seining. A 30U-foot one and one-half-inch mesh beach seine was used. Only a relatively small area of the shore line lends itself to this type of operation and for this reason 64 percent of the fish were taken at the Paradise Valley beach. This area is located near the constriction between the upper and lower i)ortions of the lake, called The Narrows. Twenty-five bass were obtained from commercial carp seiners in March, 1954. Tagging was begun on July 8, 1953, and the last fish was tagged March 25, 1954. Weather and availability of fish made this a discon- tinuous program and no fish were tagged during September, November, December, 1953, or Pebruary, 1954. Three types of tags were used. Strap tags, placed on the lower jaw halfway between the epiphysis and the angle of the mouth, were dis- continued after August 26, 1953, when a total of 108 had been placed. Three of these tags (2.8 percent) were returned by anglers. The longest confirmed elapsed time between tagging and return was 41 days. This 1 Submitted for publication October 31, 1956. (Ill) 112 CALIFORNIA FISH AND GAME o J3 3 o E 0) a o c '5) o o a Q. O LU o CLEAR LAKE BASS TAGGING 113 tag proved unsatisfactory for reasons outlined by Kimsey (1956) and is not included in any of the subsequent analj'ses. Two kinds of double-wire tags were used : the staple tag and the disk-dangler tag. These tags have been described for largemouth bass by Kimsey (op. cif.). They are placed between the soft and spinous dorsal fins about halfway between the lateral line and the mid-dorsal line. Staple tags were used until August 27, 1953, when it was found the disk was being forced backwards, exposing the wires to excessive abra- sion and causing a large persistent sore. A total of 251 tags of this type was placed. After August 27, 1953, the disk-dangler tag was used exclusively. This tag occasionally caused a sore on the knot side when growth caused the knot to pull into the flesh. Usually, however, the sore was not persistent and scales and skin soon covered it. A total of 82 tags of this type was placed. The average fork length of the fish tagged was 9.4 inches (range: 8.0 to 20.25 inches). There was a significant difference between the average fork length of the staple tagged bass (9.92 inches) and the disk-dangler tagged bass (12.0 inches). An inspection of Table 1 shows a twofold reason for this. The staple tagged fish, taken early in the season, had a higher percentage in the size range below 9.0 inches. By the time the disk-dangler tag was used these smaller fish were no longer available. This was primarily due to growth. The March, 1954, fish caught by the commercial seiners and tagged with disk-danglers were taken in a large l^-inch mesh net, so that their size (mean: 16.2 inches) was considerably greater than that of the fi.sh taken in the beach seine. TABLE 1 Length Frequencies of Fish Tagged Midpoint of size group Disk-dangler* Staple Total 8.5.. --. 16 22 8 5 3 5 6 8 6 2 35 132 40 5 11 15 4 3 2 3 1 35 9.5 .. ... 148 10.5 - ........ 62 11. 5-. 13 12.5 16 13.5 . . . . . 18 14.5 15.5 .....--- - - . . 9 9 16. 5-. 10 17.5 18.5 19.5 20.5 9 1 2 Totals 81 251 332 * One fish not measured. There was no significance difference between the size of the fish tagged and the size of the fish from which tags were returned. This was true for both kinds of tags. 114 CALIFORNIA FISH AND GAME Tag Recovery Dependence Avas placed wpuu Yoluntary returns by the angler, stim- ulated by posters advertising the program, talks before sportsmen's groups, and personal contact with boat livery and resort owners. Tagging ot' warmwater fish in noi-tlicrn California has received such wide publicity that sportsmen ai-e generally aware of the importance of tag returns. RESULTS Tag Returns An adjusted chi-square test showed tag return for the disk-dangler and staple tags was independent of type of tag (p < 0.45). The returns of both tags are combined for all subsequent analyses. First-year tag returns include all tags that were on the fish from 0 to 365 days. Second-year tag returns include those remaining from 366 to 730 days and third-year returns are considered to be those that remained over 730 days before being taken. This treatment was neces- sary because of the extended period of tagging. The tag return data are summarized in Tables 2 and 3. During the three-year period, 94 or 28.2 percent of the total tags placed were re- turned. The rate of return dropped off rather precipitously in the third year. There is, however, no direct evidence of tag loss. Using age and growth data from Murphy (1951), it was estimated that 89 percent or 297 of the tagged fish were in their second or third .summer (year classes I and II). In 1956, the third year of fishing, these fish would be in their fifth and sixth summers (year classes lY and V). Taking the annual mortality figures into consideration, approximately 30 of the original 333 fi.sh tagged remained in the population in 1956. AVith so few individuals available in a 40,000-acre lake, it is not sur- prising that returns fell off in the third year. A seasonal aspect of the fishery was indicated by the tag returns. There appeared to be two main periods of high angler success, one in the spring and another in the fall. During the peak tourist months in the summer, fishing for largemouth bass was poor. Fish, at that time TABLE 2 Tag Return Data Total number tagged Combined returns Days at large Kind No. Per- centage of total 0-365 366-730 Over 730 of tag No. Per- centage of total No. Per- centage of total No. Per- centage of total Staple _ . . 251 82 67 27 26.7 32.9 40 14 15.9 17.1 26 11 10.4 13.4 1 2 0.4 Disk-dangler 2.4 Total 333 94 28.2 54 16.2 37 11.1 3 0.9 CLEAR LAKE BASS TAGGING 115 TABLE 3 Yearly and Monthly Return of Tags 1953* 1954 1955 1956 Total January _ - February - March April May June July August September October November December. Total. 8 6 10 2 3 2 3 1 2 2 2 15 12 17 10 5 6 10 3 11 3 23 39 30 94 * Tagging started July 8, 1953, and ended Mardi 25, 1954. were obtained by deep trolling with lures or still fishing with minnows. Very few were to be found in the shallows. These periods coincide well with cliinatological information. Tag returns virtually cease in the fall when the mean daily air temperature drops below 45 degreees. They resume in the spring when the tem- perature rises above 45 degrees and continue at a good rate until the tem])erature goes above 70 degrees. The summer slumx) starts at that time and the returns are slow until fall when the mean daily air tem- perature drops below 70 degrees. The spi'ing season also coincides rather well with post-winter and spawning activity and accounted for 57.6 percent of the total tags re- turned. The summer period had 13.1 percent, the fall 26.1 percent, and the winter 3.2 percent of the total tag returns. Inclement weather dur- ing the winter, sharply reducing the effort, could account for much of the poor tag return during that period. However, seining during the winter season produced virtually no fish. The seasonal aspect of the fishery as indicated by the tag returns is also borne out by angler opinion, test seining along the shore, and by creel census data (Pintler, 1955). His data showed that 65 percent of the annual catch in 1954 was taken during the spring, 7 percent dur- ing the summer, 19 percent during the fall, and 9 percent during the winter season. Suitability of Tags Despite the sharp dropoff in returns in the third year, there is little indication that either tag was shed. One unverified report was received of a fish found with two wires protruding from the side but no tag. After the disk had turned over on the staple tag, the wires were subjected to more than normal abrasion. This was an important consideration in discarding the staple tag. However, no tag loss has been experienced with the disk-dangler tag and the rate of return in the third year also dropped off for this tag. IIG CALIl'OKXIA FISH AND GAME Movement of Fish In general, the migration of Clear Lake bass is undirected. Eighty returns carried data that could be used for migration studies. The average distance traveled was 4.5 miles.^ Seventeen individuals traveled less than one mile or not at all. The greatest distance traveled was from Point Land Ranch near Rodman Slough to Glenhaven, a straight-line distance of about 18 miles. This distance was covered in 99 days. Sixty- four percent of the fish were tagged at The Narrows. These showed a tendencj' to migrate in the direction of Clearlake Oaks more than in other directions. This tendency is magnified, since most of The Narrows anglers appeared to headquarter in the vicinity of Glenhaven. Except for the one individual reported above, the fish tagged in the Rodman Slough, Long Tule Point, and Clearlake Oaks Canal areas did not move anj^ great distance. The mean distance traveled for fish from these areas is 2.3 miles. A source of error enters into the migration data because fishermen tend to report their catch nearer to their headquarters than the actual fishing spot. This tendency is believed to increase the distance rather than to compensate, and to give apparent direction to migration. Harvest Using methods outlined by Ricker (1948), in which the survival rate is estimated as the ratio of one year's recaptures to the preceeding year, the weighted estimate of the annual survival rate was 44 percent. The annual expectation of death from all causes for the tagged popula- tion was therefore 56 percent. This over-all annual mortality rate was further refined to give a 20 percent rate of exploitation and a 36 per- cent annual expectation of death from natural causes. This means that for the duration of the experiment the anglers were annually cropping 20 percent of the population represented by the tagged sample. This is a quite moderate rate of harvest. There is no problem of overuse at Clear Lake. "While no good yardstick is available, it is reasonable to assume the angler take could be doubled with no cause for concern. Because of the limited data, these figures are of a general nature. The sharp drop off in tag returns during the third year will increase the calculated rate of exploitation and lower the annual survival rate. If this decrease in rate of tag return was due to tag shedding, the error would be real and serious. However, the evidence is against tag loss and in favor of death from natural causes, a situation tending to give the present figures more weight. Unrepresentative first-season fishing mortality caused by tagging while fishing was in progress was not found to be significant. However, the qualification of limited data also applies here. There appear to be no annual rate of harvest figures for largemouth bass that are strictly comparable with the one presented above. Rates have been reported (Dequine and Hall, 1950; Manges, 1950; Fisher, 1953; Carter, 1955; Chance, 1955; Stroud and Bitzer, 1955) varying from 9 to 41.6 percent. However, they were derived from jaw tagged fish from which only one-year returns were available. Murphy (1951) found that although several important changes had occurred in the fish populations of Clear Lake the angler, other than " All distances listed are straight-line distances and therefore minimal. CLEAR LAKE BASS TAGGING 117 reducing the number of large fish, has had no noticeable effect on the populations. The moderate angling regulations now in effect are largely the result of this information. The direct evidence of tag returns strengthen the position of these regulations. It is entirely possible that the}' could be even further relaxed, since the fish are evidently pro- tected more by natural means than by laws. Angling pressure at Clear Lake has increased during the past decade probably at a rate commensurate with the general population increase in tlie State. There is no evidence at hand indicating this increase in pressure has affected the largemouth bass supply. There are fluctuations in abundance of bass and angler success from yoar to year. Tliese are due to natural causes or to man-made conditions otlicr than angling. A more positive approach to improving fishing and smoothing out the year-to-year fluctuations in abundance and success would be to determine what these factors are and to find ways of modi- fying them. An example of this approach at Clear Lake was the inti'oiluetiou of the golden shiner, a lake spawning forage fish. This was done because irrigation demands and to some extent climatological conditions had limited the stream flow into the lake to such an extent that the stream- spawinng native forage fish were seriously inhibited. SUMMARY A tagging study at Clear Lake, which started in June, 195.'1 and terminated in ^March, 1954, tagged 441 largemouth bass. The jaw tags proved unsatisfactory and so were discontinued and not used in the calculation of vital statistics. There was no difference in the return of the staple and (lisk-(hingler tags, so they were treated together. A total of ;3.S3 disk-dangler and stai)le tags was placed. In three years 94 (28.2 percent) were returned. Of this total, 54 (o7.4 percent of total return) were received the first year, 137 (39.4 percent of total return) the second year, and 3 (3.2 percent of the total return) the third year. Tn general, the migration of largemouth bass in Cleak Lake is un- ilirected, although there is some indication that fish in the shallower northern section are more sedentary. Survival was calculated to be 44 percent. The annual expectation of death is therefore 56 percent. Of this annual mortality, 20 percent is attributed to fishing and 36 jjercent to natural causes. Overfishing is not a problem, but the extent to which the take can be increased is un- known at this time. REFERENCES Carter, Ellis R. 195."). The harvest and iiioveiueiit of game fishes in Kentucky Lake and its tail- waters. Kentucky Dept. of Fish and Wildl. Resources, Fish. Bull. no. 15, 14 p. Chance, Charles J. 1*)55. Unusually high returns from fish-tagging experiments on two TVA reser- voirs. .Toiir. Wildl. Mangt., vol. 1!), no. 4. p. 500-501. Decjuine, John F., and Charles E. Hall, Jr. 1950. Results of some tagging studies of the Florida largemouth bass Micropterus salmoides fforidaiius (I.eSueur). Anier. Fish. Soc, Trans., vol. 79, (1949) p. 155-166. 3—49892 lib CALIFOHXIA FISH AND GAME Fislier, Charles K. lUo'S. The llt."(0 liiiKfiiiuiith hhic-k bass and bluegill tagging program in Millt'iton Lake, California. Calif. Fish and Game, vol. 39, no. 4, p. 48ri-487. Kimsey, J. B. H)r>(). Largenmutli l)ass tagging. Calif. Fisli and Ciimc. vol. 42, no. 4, ]). Ij.')7-M4(i. Manges, Daniel K. 1950. Fish tagging stndies in TVA storage reservoirs, 1947-1949. Tenn. Acad. Sci., Jour., vol. 2."., no. 2, ).. 120-140. Murphy, Garth I. lit.")!. The lisherv of Clcii- Lake, Lake County, California. Calif. Fisji and Game, vol. 37, no. 4, p. 4:i9-484. Pintler. Herbert K. i;t.~i.~i. The 19r»4 lisherv of Cleai- I.;iki'. Lal. (Minieo. ) Kicker, William E. 1948. Methods of estimating vital statistics of lisli jiopulatiuns. Ind. liiiv. I'ubl., Sci. Series no. 15, 101 p. Stroud, Richard H., and Harold Bitzer 1955. Harvests and management of warm-watei- fish iiojiulnt ions in INIassachusetts' lakes, ponds, and reservoirs. Frog. Fisli-( 'uli.. \i)l. IT, no. 2, p. 51-63. SURVIVAL OF PRECOCIOUSLY MATURE KING SALMON MALE PARR {ONCORHYNCHUS TSHAWYTSCHA JUV.) AFTER SPAWNING' O. H. ROBERTSON Department of Biological Sciences Stanford University, Stanford, California The occurrence of death following the spawning: of the Pacific sal- mons (genus Oncorhynchus) is an almost unique phenomenon, since only a verv few other vertebrates are known to die regularly after their first reproduction. These are all fishes; they include the eels (genus Ancjuiila), the lampreys (family Petromyzontidae), the eulachoii (Thaleichthys pacificns), and a group of small annual fishes (genus Cynolehias) of the killifish family. The last group lives in water which dries up once a year. They spawn in the mud as the pools begin to dry and tlie eggs, buried in the damp mud beneath the hardened crust, hatch after the next rain. Death occurs after spawning even though the fish are maintained in water (Myers, 1952). The ayu (Plecoglossus altivflis), a small salmon-like fish of Asiatic rivers, and two small marine gobies of northern Europe {ApJiya pellucida and Crystallogo- hius nilssoni) also are said to be annuals.^ The nature of the post-spawning death presents a problem of great interest. Physical exhaustion resulting from long migrations can be excluded as a principal factor, since salmon running up short streams may come to the spawning ground in excellent condition, and after shedding their sex products, undergo degenerative changes which lead ra])idly to death. Is it the loss of sex products that initiates this lethal process, or some profound physiological change associated with sexual maturation, or is the life cycle of each species of Pacific salmon sharply limited, spawning constituting the final phase? An approach to the study of tliis subject has been made by observing the fate of certain individual salmon which spawn long before the age at which their species commonly matures. There occurs in natural as well as in hatchery populations of young king salmon (0. tshawytsdia) and silver salmon (0. l-isufch) a curious phenomenon of precocious sexual maturity in a small percentage of the male fish when less than a year of age. (King salmon spawning runs are usually composed of fish in their first through their sixth year of life, dominated by those in their third and fourth years. Silver salmon spawn in their second, third, and fourth years, with three-year fish dominating.) Do these little males die after losing their sperm? The ^ Submitted for publication October, 1956. This work was aided by a grant from the American Philosophical Society, Philadelphia. - 1 wish to express my appreciation to Dr. George S. Myers, Natural History Museum, Stanford University, for information on this subject. ( 11!>) 120 CALIFORNIA FISH AND GAME author has been able to find very little information on this subject. Kutter (1902) described precociously mature male king salmon parr in the Sacramento River. Milt secured from such fish fertilized adult salmon eggs which hatched normally. He stated that nothing is known about their survival after spawning but considered that they may sur- vive and return later from the sea as grilse. Donaldson (personal com- munication)^ examined the preserved specimens of six kokanee salmon (nonmigratory sockeye or red salmon, O. nerka kennerlyi) 9 to 10 inches in length caught in the spring of the year in Chapman Lake, Washington. Five of these fish, three males and two females, showed undoubted evidence of having spawned previously — presumably during the preceding fall. All had food in their stomachs. An opportunity to study a hatchery population of precociously ma- ture king salmon parr was provided by the California Department of Fish and Game at their Prairie Creek Hatcherv near Oriek, Humboldt Count5^ The following report consists of observations on a group of such fish maintained for five months following full sexual maturity and artificially induced spawning. THE EXPERIMENTAL SALMON The salmon employed in the experiment were hatched t'roin eggs and sperm obtained at Fall Creek, a tributary of the Klamath River. Hatch- ing was completed about the middle of January, 1954. Examination for the occurrence of sexual maturity (by expression of milt) was begun September 19, 1954, in a stock of approximately 5,000 fish. Two hundred were tested each week. None were found until October 3. From that time until November 21 there was a gradual increase in the number of ripe parr collected Aveekly. The total represented 2.3 percent of some 2,000 of the population examined. The actual incidence may have run ;i little higher, since on November 24, 42 additional ripe parr were picked out from the remaining but uncounted stock primarily on the a|)])earance of a lemon-yellow coloration of the belly and the pectoral, l)elvic, and anal fins, characteristic of the precociously mature male. Practically all such fish were found to be ripe. The age of the salmon at the initiation of the experiment on No- vember 24, 1954, was a little over 10 months. They were in excellent condition and had grown normally. PLAN OF THE EXPERIMENT Of 70 ri])e ])arr collected, GO were kept for the experiment and 16 killed for examination of the testes. One hundred thirty immature fish were held as controls. All the fish were measured iiulividually (total length) and weighed in groups of 10 or 20 after anesthetizing in a 1 : 25,000 solution of tricaine methanesulphonate. From 40 of the ripe ])arr milt was expressed (before weighing) as completely as possible. These were marked by clipping the adipose and right pelvic fins, as dis- tinguished from the non-expressed with adipose and left pelvic fins clipped. The controls were not marked. These data are displayed In Table 1. It will be noted that the immature controls averaged one-half •■' I am much indebted to Professor Jjauren R. Donaldson, T^niversity of Washington Scliool of Fi.sheries, for sending me a tran.seript of his unpublislied notes on these salmon. PRECOCIOUS MALE KING SALMON 121 TABLE 1 Lengths and Weights of Salmon at Beginning of Experiment Number and classification of fish in each group Average length, inches* Average weight grams 40 ripe males milt expressed - 4.7.3 4.7.5 5.25 19.6 20 ripe males, milt not expressed. 19.7 130 immature controlsi" 23.5 * Total length. t Later 61 were found to be males. inch longer and four prams heavier than Tlic mature fish. Tin' lad that the ripe parr from Avhieh milt had been expressed weighed essentially the same as the nonstrijiped gronp may be aeeonnted for, at least in part, by tlie finding in the antopsied gronp that the testes of many of the latter gronp were partly spent (Table 2). TABLE 2 Data on Ripe Parr Autopsied at Beginning of Experiment Salmon number Length, inches 1 2 3 4 5 6 7 8. 9 10 11 12 13 14 15 16 5.0 4.8 4.7 4.5 4.2 3.8 5.4 5.1 5.4 4.6 4.7 4.3 5.1 5.0 4.2 4.1 Weight, grams 23 . 5 18.5 17.5 16.5 13.25 9.0 31.5 22.5 29.5 19.5 18.0 15.0 23.5 22.0 15.0 11.25 State of testes Soft oozing sperm Partly spent Partly spent Partly spent Soft oozing sperm Mostly spent Soft oozing Partly spent Soft oozing Soft oozing Soft oozing Soft oozing Partly spent Partly spent Partly spent Partly spent Weight of testes, grams 25 25 25 5 75 3 5 ,4 0 ,7 3 2 5 3 ,5 ,5 Percentage testes weight of body weight 22 7 13 9 21 3 21 11 24 19 7 21 11 10 10 13 Average = 14 All the experimental salmon were placed in the same trough, where they Avere maintained for the duration of the experiment. STATE OF THE TESTES In the 16 ripe parr autopsied, the testes were found to be mostly in a partly spent state. A summary of the findings is given in Table 2. The size of the testes in relation to body weight was surprisingly large. In 6 of the parr which appeared not to have begun to lose their sperm, the testes comprised 19 to 24 percent of the body weight. Figure 1 (upper) 122 CALII'OKNIA FISH AND (iAME FIGURE 1. Upper: Precociously mature king salmon parr 10 months of age. tower; Same salmon as above with right testis exposed. Weight of testes 6.5 grams; equals 21 percent of body weight. shows the bulging abdomen of salmon No. 7, whose testes represented 21 percent of the body weight. The exposed right testis of the same fish is exhibited in Figure 1 (lower). The author has been unable to find comparable data for adult male salmon, but believes from personal ob- servations that the testes weights of the precociously mature parr are relatively much greater than those of the sexually ripe adults. So, if loss of sex products is the precipitating cause of the sequence of changes ending in death, one would certainly expect these fish to die. Examination of the scales for absorption at the periphery was made in only six of these fish, since similar observation had been made in 30 such parr previously. This was done in an earlier unfinished experiment, described later in the present paper. None of the scales showed absoriD- tion. PRECOCIOUS MALE KING SALMON 123 FERTILITY OF PRECOCIOUSLY MATURE MALES While there is reason to believe that these sexually mature male parr produce fertile sperm, as shown by Rutter (op. cit) for wild king salmon and by Orton, Jones, and King (1938) for Atlantic salmon (Salmo solar), it was believed desirable to secure conclusive evidence on this point for the particular population under observation. Accordingly, eggs from two adult females were fertilized with milt from ripe parr — two parr to each female. The results are displayed in Table 3. The per- centage of eyed eggs and the hatching of eggs from female No. 1 were fully as good as those occurring when salmon eggs are fertilized with milt from adult males. In the case of female No. 2 the resulting hatch was lower than expected. The early mortality of the latter fry was, however, very low. TABLE 3 tggs of Adult Females Fertilized by Sperm of Precociously Mature Parr Number of eggs Percentage mortality Taken Eyed Hate lied at the end of 2 months Female No. 1, partly spent, weight approx. 12 lbs. Female No. 2, rijjc, \voii;lit 23 lbs 1,200 4,290 1,161 96.8% 3,444 so.:^'*; 1,120 90.3% 3,362 78.4% 3.0 0.7 INTERIM OBSERVATIONS Tlie spent males graduall}^ lost their distinctive lemon-yellow colora- tion of belly and fins and became indistinguishable from the immature controls. Tliey fed well, continued to grow, and only four of the group died, a mortality only slightly higher than tliat exhibited by the im- mature control males, of which three succvimbed (Table 4). CONDITION OF THE EXPERIMENTAL SALMON AT THE END OF FIVE MONTHS Oh April 1!», 1955, all the salmon parr in the experiment were measured and weighed, scale samples were taken, and the fish were then killed by immersion in a lethal concentration of tricaine methane- sulplionate, and autopsied. The testes of the three different categories were weighed in groups. Samples of each were put in Bouin's solution for histology. The spent testes were strikingly different in appearance from those of the immature controls. The former were larger, flesh-colored, and lacked the surface marking of the longitudinal artery which character- ized the undeveloped male gonad. There was also a difference in appear- ance between the expressed and non-expressed testes. The latter were a little larger and contained small amounts of milt which could be squeezed out of the incised gland, while the former were "dry." This observed difference in milt content was borne out by the testes weights of the two groups. Testes of the milt-expressed group averaged 143 mg., ]24 CALIFORMA I'lSll A.\l) (iAME o w Q- ■^ fO 1 1 1 CO > c3 .-ti o 'C o 05 C "3 " O »o d o ^ (SS a> l.s% -t o S SM t- X t^ o fJ IS 'oj cc CO o s M^ ^ o c3 -r, S 00 CO o LO S: M S 0) r" ra g ?^ !-. o r^ t^ l^ C^l M C-l CO V M -g .s* 00 00 cc 1 Cm >Q >o 00 l> ri G ^ Mii Ph o fc£. j2 "5 d +2 o a -jj-- a 3 O u M jS o ca o c c c « ■a V. ; o ^ c o -a o "3 1 a c. 0} 1 C 0 J ^ *- u. o _2 •— ■— •^ "g -a - " tA ce aT «" S o c- o b. L> lU "a "3 „^ ~ s E c: 3 3 Q. ^ ~ Z 'C 'C = .E 00 00 o a 00 CO iC PRECOCIOUS MALE KING SALMON 125 while those from tlie non-expressed weighed 201 mg. The average weight of the immature control testes was only 44 mg. The data secured at autopsy are summarized in Table 4. Of chief interest was the finding that the spent salmon parr showed almost as much increase in length at the end of five months as did the immature controls. The latter, however, gained more weight, as might be expected. None of the 57 spent fish showed any absorption of scales. HISTOLOGY OF TESTES Microscopic examination of testes taken from the sexually ripe parr sacrifieed at the beginning of tlie experiment showed them to be in FIGURE 2. Upper: Spent testis of king salmon parr. Some lobules still contain considerable numbers of spermatozoa; others are almost empty. X TOO. tower: Higher magnification of same testis shown above. Note spermatogonia lining lobule are almost all intact. Dense masses of spermatozoa lie in the middle of the lobules. X 500. iLMi CALIFORNIA FISH AND GAME varying stages of post maturity, i.e., partly spent. The only free sex cells Avcre spermatozoa. In some instances relatively few spermatozoa remained. Figure 2 (upper and lower) shows the typical appearance of such a testis : small lobules with much thickened interlobular septa. Some of the spermatogonia lining the lobules showed evidence of degen- eration, necrosis of cj^toplasm, and occasionally vacuolization. Evidence of cell injui'v varied nnidi between difl'ci-eiit fish. Some testes appeared essentially normal. In otlioi's, considerable degenerative change was observed. FIGURE 3. Upper: Renewed spermatogenesis in spent parr testis five months after spawning. X 100. lower: Higher magnification of an area in same testis. Larger cells ore spermatogonia, next sizes smaller are primary and secondary spermatocytes, while small solid dots are spermatids. Cells appear normal. X 500. PRECOCIOUS MALE KING SALMON 127 Testes secured from the spent parr five months after the loss of their sperm revealed a picture of renewed spermatogenesis. In certain cases the process was well advanced, as shown in Figure 3 (upper and lower), and had progressed to spermatid formation. Others showed onh' multiplication of spermatogonia, with frequent mitoses. In most of the testes examined there was much more fibrous tissue in the septa and capsule tlian was observed in the testes taken from ripe parr at the beginning of the experiment. Some showed large areas of fibrosis, giving the appearance of scars. The fibrous tissue in certain testes was arranged concentrically around a mass of degenerating cells (Figure 4, upper). On higher magnification there Avas seen within the central ■rf ^\-i t^ cV ■i'MT. f-rwi*!;*.-, > :*:"^'v FIGURE 4. Upper: Testis of another spent parr five months after spawning, shows marked fibrosis. The scar tissue is arranged concentrically around a mass of degenerating cells. X 150. tower: Infantile testis of control salmon killed at same time as fish whose testis is shown in Figure 3. Here the only sex cells are small nests of resting spermatogonia. X 500. 128 CALIFORNIA FISH AND GAME mass a larfre number of small, vai'vinp-sized, dark-staining particles suggestinjir bacteria, since they api)eare(l to be encapsulated. However, on appeai-ance alone disintegrating spermatozoa cannot be excluded. Testes of tlw iniiiuiture controls ;ii ilic cihI of tlie experiment were found to be in a typical infantile state, as exhibited in Figure 4 (loAver). The only sex cells seen are spei-matogonia wliicli are arranged in small nests. OFFSPRING OF SMALL PRECOCIOUS MALES AND ADULT FEMALES The fry resulting from the fertilization of adult salmon eggs with ])arr sperm continued to develop normally. Beginning at the age of nine months and continuing till the end of their first year, 200 were examined each week for the prescence of precociously mature males. Not one was fdund. DISCUSSION Deatli of the adult king salmon occurs in almost all instances within one to two weeks after spawning. B}^ means of tagging Rutter (1902) determined that fall-run king salmon live only an average of two weeks after reaching the spawning gi'ound and believed that most of them die shortly after spawning. Several of his marked fish lived as long as 16 days. It is possible that a rare spent salmon may survive for longer jieriod-. l)ut that none live to spawn a second time is attested by the failure to find a single spawning mark in tens of thousands of scales examined by many workers. Tlie fact that the spent male parr of the present study were not only alive but grcjwing normally at the end of five months after full sexual maturity and expulsion of their sperm would seem to provide sufficient evidence that they had escaped the fate of their progenitors. Addi- tional evidence for continued life expectancy was the presence of re- newed s])ermatogenesis. Age appears to be the deciding factor in determining death or sur- x\yd\. Possibly related to this factor are certain differences between the ripe \)Hvr and tlie mature male adult salmon: namely, the p-dvv do not show the hooked jaw, the hmn]) back, the brilliant coloration, and absorption of scales exhibited by the full-grown fish. These changes are all i)resumably the result of increased pituitary activity and signify ;i much iiio]-e diversified functioning of this gland in the adult salmon. It is conceivable that other changes characteristic of the post-spawning state may be also influenced by the pituitary. The histological ai)i)earance of the testes of the spent parr differs considerably from that of the post-spawning adult salmon described by AVeisel (1948). lie found that the residual spermatogonia showed marked degeneration: vacuolization and necrosis of the cytoplasm and pycuosis of the nuclei. In the testes of the spent parr a modi^-ate amount of degenerative change was observed, obviously not enough to prevent the re-establishment of spermatogenesis, but sufficient to cause considerable scarring. Examination of the testes of grilse for scars might provide a clue as to whether they are the previously spent ripe ])arr returning for a second spawning. Why a small percentage of king salmon populations should mature at an early age poses an interesting question. Insofar as cau be deter- PRECOCIOUS MALE KING SALMON 129 mined, enviroiinu'iital and nutritional influences can be eliminated. Is it genetic ? Such data as we have suggests that this may be the case. A duplicate of the present experiment was set up two years previously, in which the population producing the ripe parr was derived from eggs secured from Fall Creek, a tributary of the Klamath River. Two to three percent of precociously mature parr occurred in this hatch. The experiment was terminated after seven weeks by a flood. Up to that time the spent parr were all alive and doing well. The next year eggs were obtained from RedAvood Creek, a short coastal stream. No ripe parr occurred in this population of young salmon. Then, to secure ma- terial for the i)resent experiment, salmon from Fall Creek w^ere again used, with the resulting two to three percent of ripe parr. Finally, to test the fertility of the precociously mature parr, salmon from Redwood Creek were used for the source of eggs. The resulting hatch, as stated above, produced no ripe parr. More extensive observations would, of course, be needed to be sure that certain runs or races of salmon carry the gene or genes for precocious male sexual maturity and others do not. SUMMARY As an approach to the study of the nature of post-spawning death of the Pacific salmons, an experiment was conducted to determine the fate of certain king salmon parr which mature sexually in their first year of life. Sixty such ripe parr were held in a hatchery trough, together with 120 immature controls, 61 of which were later found to be male fish. Autopsj^ of other matui-c ])arr from the same population showed relatively huge testes, com{)rising as much as one-fourth of the body weight. Test of the maturity of the sperm of these fish was made by fertilizing the eggs of adult females. The eggs hatched and the young salmon developed normally. At the end of five months the spent males had survived and grown as well as the immature controls. Histological examination of the testes of the ripe parr taken at the beginning of the experiment showed them to be completely mature or partially spent. Five months later the spent parr exhibited renewed spermatogenesis, while the controls had infan- tile testes. Age appears to be the deciding factor in determining death or survival of this species of salmon following spawning. ACKNOWLEDGMENTS The author wishes to express his very sincere appreciation to the California Department of Fish and Game for providing the opportu- nity to carry out the above experiment. Especial thanks are due Monte R. Brickej", Steven C. Smedley, Carleton Rogers, and Duane T. Rodman for their generous assistance during the study. 13U CALIFOKMA 1 l>ll AM) (iAME REFERENCES Mvcrs, (J. S. 1952. Annual fishes. Ai|ii;iriuiii .Idiir.. \n\. '2'\, im. 7. \<. l-!.~)-141. Orton, J. H., J. "\V. Jones. ;in, j). l().".-n4. Rutter, C. 1902. Natural history of the quinnat salmon. A i-eport on investigations in the Sacramento River 1890-1901. U. S. Fish Coiiiin., r.nll.. vol. 22, p. fi.'l-Ml. Weisel, G. F. 1943. A histological study of the testes of the sockeye salmon {Oncorhynchus 7ierka). Jour, ^[orph., vol. 73, no. 2, p. 207-229. DETERMINING THE SEX OF DRESSED PHEASANTS' MILTON HILDEBRAND Department of Zoology University of California, Davis In certain proseentions of game law violators it -would be desirable to establish the sex of a pheasant from the dressed bird. Some hunters and wardens can sex such birds with accuracy on the basis of the greater size and firmness of the body of males; however, a judge may quite properly require evidence established by exact methods. This paper describes sexual differences evident in dressed pheasants as de- termined in a study of the soft parts of five male and five female birds, and of the skeletons of 28 males and 25 females. Most of the birds used were reared at the Yountville State Game Farm. Helpful suggestions were receiA'ed from L. W. Taylor, Depart- ment of Poultrj" nusbaudry, University of California, and Chester Hart, California Department of Fish and Game. The figures were drawn by my wife, Viola M. Ilildebrand. SOFT PARTS AVlien dressing his pheasant the hunter removes the feathers, head, unfeathered portion of the legs, and most or all of the viscera. If one or more small feathers have been overlooked where the skin of the neck was cut, they will establish the sex of the bird: when clean and dry they are tipped with dark iridescent blue in the male, and with a shade of tan in the female. Feathers found where the legs have been cut are a darker brown in the cock than in the hen, but quite small feathers in this position will not establish the sex. ^lost hunters skin their birds or pluck them cleanly; the examiner must therefore turn next to the body cavity for clues to sex. If one or both of the small, ovoid, yellowish testes, or the single, flatfish, white-spotted, gray ovary is in position at the forward end of the kidney, the search is over. However, the sex organs are usually removed, or at least damaged, when the bird is eviscerated. Yet the kidneys are often left in the bony hollows of the back — the usual practice when poultry is dressed for market. Studies of chickens (Latimer and Osborn, 1923) have shown that the kidneys, unlike the liver and some other organs, are nearly identical in the two sexes. However, the sex ducts that traverse the kidney afford sure identification, and the smaller of these may remain if the kidneys are present. The small, yet tough, yellowish ureter emerges from the kidney at a point about two-thirds of the length of that organ from its forward end, and runs back to the cloaca. The sperm ducts (deferent ducts) 1 Submitted for publication July, 1956. (131) ■ >.) CALIFOKXIA 1 iSll AM) (;AME take thoir ori'jfiii at tho testes, run l)aek adjacent to the dark-red renal veins, and continue lateral to the ureters. In cocks of three to four months of age these ducts are nearly straight and only faintly visible; by four and one-half months they have become more evident and are tightly convoluted, as shown in Figure 1, but a hand lens may still be required to reveal the convolutions. MALE FEMALE Adrenal qland Vfein (iliac) Artery (aorta) Uterus Bursa of Fabricius FIGURE 1. Urogenital organs showing structures that fwhen present) indicate the sex of a dressed pheasant. The vestigial sperm ducts of the female are too minute to be surely identified after the viscera have been disturbed. The oviduct and uterus on tlie right side of the body are represented by a mere rudiment, Avhich -will almost certainly have been removed Avith the cloaca. The left oviduct has its origin lateral to the forward end of the kidney. It is a whitish or yellowish duct of variable size. Opposite the middle of the kidney it expands into the shell gland, or uterus. All of the uterus may have been removed with the cloaca, yet if a portion remains it is easily recognized by its relatively large size and b.y the folds that cross the oi'gan diagonally, as illustrated. All of the reproductive structures are much larger during the breed- ing season. They return rapidly to the involuted condition soon there- after, and are then scarcely more evident in old birds than in the young of the year. SEX DETEKMIXATIOX OF PHEASANTS 13} SKELETON If the urogenital ducts are not available, the search for clues to the identification of sex must be carried elsewhere. Latimer and Kosen- baum (1926) have shown that with turkeys and chickens there is less individual variation in the skeleton than in other organ systems. Vari- ability is equal in the two sexes (Schneider and Dunn, 1924). Further, for several reasons, linear measures of skeletal parts of poultry show less individual variation than do skeletal weights (Latimer, 1927; Latimer and ^Yagner, 1941) . The most prominent sexual dimorphism in the pheasant skeleton is that of size, and in other fowl the skeleton shows greater sex differ- ences in size than do other organ systems (Latimer. 1925 and else- where). Schneider and Dunn (op. cif.) reported high correlation in size variations of different bones. It follows that linear measures of the skeleton slioiild demonstrate differences between cocks and hens if lliey can be determined in the dressed bird. Birds of 4 to 17 inontlis of age were studied. Li domestic fowl, female skeletons mature faster than do those of males (Latimer, 1927), but age-class analysis demon.strated that regardless of sex, the skeletons of pheasants four months of age conld not be distingnishod from tliose of older birds by linear measures. Since .some parts of the skeleton may be broken by shot, it will be useful to present measurements for a number of bones; however, since the.v are not equally diagnostic. Table 1 shows oidy those five of the 21 measures tested for which means for the two sexes differ by four or more standard deviations. Ten other measurements showed correspond- ing differences between three and four standard deviations. The bones listed in the table are identified in P^'igure 2. TABLE 1 Differences Between Cock and Hen Pheasants in ttie Size of Certain Bones '■■ Cocks Hens Measurement No. Mean Standard deviation No. Mean Standard deviation Depth of keel 27 27 28 27 28 46.81±.29 85.21±.37 112.73±.60 53.57±.29 76.78±.41 1..50 1.88 3.11 1.48 2.11 24 25 25 25 24 38.98±..36 76.12±.41 99 . 62 ± . 50 47.24±.28 68.62±.38 1.76 Length of femur 2.04 2.49 Length of coracoid. 1..39 Length of humerus- . . 1.87 * Measiirtments in millimeters. Measurements were taken to the nearest tenth millimeter. Lengths of long bones are maximum over-all lengths. The depth of the keel of the breast bone was measured in the plane of the keel from its deepest extremity to the upper edge of the trough of the saddle that receives the lower ends of the ribs. Results agree with those of Latimer's work on the chicken (1927 and elsewhere) in finding that the humerus and tibiotarsus show rela- 134 (AI.IIOKMA IMSII AM) GAME J2 a -a c o J2 e « TJ o SEX DETERMINATION OF PHEASANTS 135 c o o ^ & c ;3 Q_ CO O J- D_ D ■-»- CD CD O -d -M c _i- ?^, & c_ _i_ O n" $ -D C >- a> 0 -^ -a 0 c -^ 0 — ^ § 1. -□ s:> '*- -D o.E c O o 5 ^ •*- 0 X j: J2 — S "c .9 T3 ~ 0 0 = 0 a o -o Q. OJ (A 1? *" Q. «- X o v C O 0 J2 0) 0 c t 0, a ? 5 u; ■•" cfl £ E S e-5 w ^ CJ ^ > (- 4-* 0 V 4) t: ^ CJ o J J— = Q. a> Of OJ) o ^ -0 -^ - - >^ n -a-. C 3- — • -^-J 0 o — Q> O r S > ^1 0) t Cl) u .C -C ^ ij c 0 S— OJ rt b -n> 0 2 OJ c O 3 CJ •^ -Q E -J—" Q- _- o CO 0) fc^ ^ 0 E 3 ^ 2 E D *■ 0 0 0 C 0) OJ -D »- i» 0) o 13 Q. CJ III > 3 O -C O * — J2 .E aj fc o -n i 0 c o o jC ^ ^ , ^ .2 0 1^0 c 0 -^ o O^ 0 ■ — D Q. n •: n n. q: '-^ a =3 .5 E n o > U- -O ^ l:',(i (■AMI'OK'MA I'ISII AXn flAME tivelv iiiiicli, ;iii(l llic r;i(liiis .iiid iiliiji relatively little, difference in size between the sexes; the rciimr sliowcd more sexual diiiioi-phism in the l)r(\sent study. Tliese dale! i)r()vi(h' certain ideiii ilieatiuii uJ' most birds. The method of interpretation is as follows. TiCt ns assume that the do))tli of the lan for hens by tlire(> and one-half standard deviations the odds dro}) to one in r),0(JO. intermediate values can be approximated from the figure. (These values are functions of areas under the normal distribution curve beyond the stated distances from the mean. The tabulation of these data in Simpson and Roe (1939, page 137) was used in deriving this example, and in preparation of Figure 3.) As expressed by IMayr, Linsley, and Usinger (1953, page 133) "... in biological populations, certain upper and lower extremes do not occur. There is no bee as large as an elephant or as small as a bacterium, no matter how many billions of bees are examined. Even though a finite linear range of a population does not exist mathematically, the part of the curve bej^ond three and one-half or four standard deviations is of negligible practical importance in work with natural populations." Thus we may decide that a bone having a keel exceeding the mean depth for hens by three and one-half standard deviations (or more, de- pending upon the criterion adopted) is almost certainly not from a hen. Do cocks have keels enough deeper to permit identification on this basis! Referring to Figure 4 we see that most, but not all, cocks would be so large. 35 40 45 50 M. en3 Cocks '"' ""■>— t""?. 0 12 3 4 Standard deviations from mean tor hens FIGURE 4. Depth of keel of the breast bone in millimeters. Interpretation in text. SEX DETERMINATION OF PHEASANTS 137 More specifically, if three and one-half standard deviations above the mean is taken as the upper limit of variation in hens, then about 91 percent of all cock birds will have still deeper keels. (Taking 1.65 as the standard deviation in each sex, a variance of 3.5 standard devia- tions from the mean for hens chances to fall 1.37 standard deviations from the mean for cocks. Tables show us that 83 percent of a popula- tion falls within these limits, and in this instance only the lower limit of variation in cocks is pertinent.) Eighty percent of cocks will have keels deeper than a value exceeding the mean for hens by four stand- ard deviations. This is to say that 80 to 91 percent of the pheasants that might come to hand can be designated male or female on the basis of this character, depending upon the criterion of certainty adopted. One would be justified in testing a number of the measures tabu- lated, and in accepting as evidence the one that best suits one's case; however, as all express differences in size, they do not vary independ- ently, and one may not extend the analysis by employing the product of several probabilities (llildebrand, 1955). This could be done with most ratios expressing l)ody i)r()port ions, but non(> of the nine indices tested showed sufficient sexual dimorphism to be useful; several ratios revealed statistically significant differences between the sexes, yet the overlap of values was too great to permit api)lication to single birds. In cocks, the keel of the breast bone is deeper in relation to its h'nglli, nnd several long bones have greatei- thickness of shaft in pi-opoi-tion to length. Sexnal differences in the pelvis that are evident during laying are not useful during the hunting season. Certain avian bones develoj) hy])ei'ossification undei- the influence of estrogen (see, e.g., Ijandauei-. IM'eiffer, Gardner, and Shaw, 1941, and citations therein). The head and shaft of the tibiotarsus of 54 jiheasants were sectioned and examined for differences in thickness and density of bone. N'ariation was marked, but, as exi)ected, there was no con-ela- tiou with sex in these nonbreeding birds. SUMMARY To enforce certain game laws it is desii'able to be able to sex dressed pheasants. If the kidneys ai"e in place a portion of the sperm duct or oviduct may remain in position. When urogenital structures are not available, linear measures of any of several bones nearly always offer cei'tain identification. Data are tabulated for five suitable measure- ments, and the method of interpretation is discussed. No useful differ- ence in relative body proportions could be found. Pelvic variation and estrogen-induced hyperossification are us(^ful oidy during the laying season. 138 CALIFORNIA FISH AND OAME REFERENCES Hildi'hiMuil. Milloii 1955. Skolctiil (liffcrcneos hotwccn deer. s1i(t|). iiiid jro.'its. Calif. Fish and Game, vol. 41, no. 4, p. '.i27-'S4V>. Landaucr, "S^^^lter, C. A. l»feiffor, W. U. Gardner, and J. C. Shaw 1941. Blood scrum and skeletal changes in two breeds of ducks receiving estro- gens. Eiidoerinology, vol. US. no. 8, p. 458-464. Latimer, Homer !>. 1925. Postnatal gmwlli of the hoil,\. systems and organs of the single comb white leghorn chicken. .lour. Agric. lies., vol. 29. no. S, p. 8G3-397. 1927. rost-natal growlii of tlie chic]., and .lolin L. Osliorn 1923. TIh' tojiograpliy of the \iscera of tlic chickrii. .\ii;it. liecord, vol. 2<), no. 1, |,. l.'75-L's;». Latimer. Homer H.. and Jolm A. Rosenhaum 192(>. A quantitatixe study of the analomv of the tiirkev lien. .\nat. Record, vol. 34, no. 1. ],. 15-23. Latimer, Homer !>., and H. P. Wagner 1941. Weights and linear dimensions of the skull and of some of the long hones of the mallard duck ( Ana.s pJiitjirhipichoK jilntiirhi/iirhos). I'niv. of Kan- sas Sci. Bull., -^ol. 27. no. 1, p. 15-18. Mayr, Ernst, E. Gorton Linsley, and Robert L. Usinger 1953. Methods and principles of systematic sicwlogy. N. Y., McGraw-Hill Book Co., Inc., 328 p. Schneider. ^NL, and Ti. C. Dunn 1924. On the length and varialiility of the bones of the wiiite legiioru fowl. Anat. Record, vol. 27. no. 5, p. 229-239. Simi)son. George Gaylord, and Anne Roe 1939. guantitative zoology. N. Y.. .McJJraw-IIill I'.ook Co.. Inc.. 414 |). STUDIES ON THE INCIDENCE OF POULTRY DISEASES IN WILD DUCKS' ERLING R. QUORTRUP, M. E. GOETZ, and J. W. DUNSING San Diego County Livestock Department and MERTON N. ROSEN Game Management Branch California Department of Fish and Game INTRODUCTION This study was undertaken in order to obtain data on some of the more important diseases transmissible from poultry to wild birds and vice versa. Answers to the problem are of equal interest to the poultry producer and the conservationist or game manaiiiiir. .1. F. ^9~n>. The isoliitioii of Sah)iO)ieUa gfilHiKirum in wild birds. Jour. Comp. Pnth., vol. 65, no. 3, p. 250-254. Quortrup, Erling R., M. E. Goetz, J. W. Dunsing, and Merton X. Rosen 1!>57. Studies on the incidence of poultry disea.ses in wild ducks. Calif. Fish and (JauK'. vol. 48. no. 2. j.. i:!r)-141. Rausch, Robert 1947. Pullornm disease in the coot. .Toni'. Wildl. Man<,^t., \nl. 11. nu. 2, p. 189. NOTE TAGGED DOVER SOLE (MICROSTOMUS PACIFICUS) AT , LIBERTY SIX YEARS A dover sole tagged by the California Department of Fish and Game in 24 to 26 fathoms of water off the mouth of Mad River, in Fish and Game block nnmber 202, on July 13, 1950, was recovered from this same general area on Augnst 24, 1956. This fish had been at liberty 6 years 1 month 11 days, or a total of 2,234 days. According to Depart- mental records, the next lengthiest time at liberty for a tagged dover sole was about 3 years 11 months. The fish at liberty six years was tagged with a i'elersen-disk-type tag made of cellulose acetate, which was attached by a silver-wire pin jnst below the dorsal fin approximately halfway back on the body. Among the many species of marine and freshwater fishes simihirly tagged by the Department only sablefish {Anoplopoma fimhria) have been re- covered after being at liberty a comparable length of time. A record of 5 years 6 months has been established for the sablefish (J. P>. Phillips, personal comnninication) . The tagged dovei- sole was recovered on the fiUet line at the Hunter and Foland Fish ('omi)aiiy at Fields Landing, California. It was part of a load of fish delivered by Mr. Byron Anderson of the vessel Winga. Unfortunately, only the tags were turned in to Department personnel, but subsequent interviews of employees of the fish company determined the length of the specimen to be "about 15 inches" and tliat the tag wound was well healed, with no apparent irritation. At the time of release in 1950 the fish measured 13 J inches (344 mm.) in total length. Mr. Anderson stated that he had been fishing in only two areas: Fish and Game block number 134 otf Trinidad Head in 130 fathoms, and Fish and Game block number 211 off Humboldt Bay in 90 fathoms. Both areas are approximately equidistant from the point of release. In any event, the net movement after six years was less than 25 miles. — E. A- Best, Marine Fislwnes Branch, California Department of Fish and Game, October, 1956. (147) 148 CALIFOKMA FISH AXl) (iAME IN MEMORIAM CHARLES R. CLOTHIER Tt is with real sorrow 1l)Mt we rcpoi-t the ])assin<>- of Charles R. Clothier, Marine Biologist 11. on .laiiuary 10, 1957. Mr. Clotlner came to work with the Division of Fisli and Game in 193."), and transferred to tlie Tei'iiiinid island laboratoi'v in 1945. His willin.miess to taelvle any tonuli assi1. The California Department of Fish and Game receives many inquiries concerning the care and culture of various kinds of fish baits. Undoubtedly, fish and game depart- ments of other states do. too. In the iiast, it has been necessary to hunt up answers in scattered leaflets and publications and has not been possible to refer the inquirer to a single source of information. Krochmal's booklet supplies many, if not most, of the answers to the questions most frequently asked. Written in an easy-to-read style, this handy manual presents information on collecting, rearing, storing, and selling both the usual and less frequently used freshwater baits. Included are earthworms, minnows, suckers, smelt, hellgrammites, crayfish, frogs, crickets, grasshoppers, cockroaches, meal worms, and other natural baits. The booklet also contains hints on fishing with the different baits described. The author writes frimi first-hand experience of long standing. Both fishermen and bait dealers should find his booklet well worth the dollar cost. — Leo tihupovalov, California Department of Fish and Game. REVIEWS 155 Fresh and Salt Water Fishing By Stan Smith; Dell Publishing Co., Inc., New York, 1956; 145 p., illus. $0.75. Probably most anglers have at least an occasional yen to try their luck in some far-away place. The first part of this guide maps and describes briefly 151 "hot- spots" in the United States, Alaska, Canada, and Latin America and lists informa- tion on clothing, equipment, travel rates, and license fees. It also offers suggestions as to what the wife not fishing might do in the various places and, perhaps most important of all, tells to whom to write for detailed fishing information. The second part of the booklet contains a number of individual articles on fishing for various freshwater and saltwater fishes and on tackle. As is almost invariably the ca.se with wide-scale compilations, there are some specific errors. Also, many an angler will snort indignantly to find his favorite water omitted from the list of 151 great fishing spots. On the whole, however, the average angler will glean a fair picture of the kinds of fishing availal)le over the area covered.- — Leo Shapovalov, California Department of Fish anil (iume. Kingdom of the Beasts By Julian Ilu.xley ; The Vanguard Press. New York. 105(1; SO p. and 175 photo- gravure i)late.s, 3 in color, by W. Suscliitzky. $12.50. This book is very easy to read. Representative mammals, extinct and living, are described in a way that emphasizes their outstanding characteristics. This is done Avith a humor that makes the mammal and its individuality easy to remember. Who could forget the fish-catching al)ility of the polar licar after reading of tlie one '■presented by the King of Xorway to liis Royal Brother of England in the 32tli century, let out from the tower at the end of a long rope, and catching Thames salmon?" The author explains why the various mammals are what they are and how they have become what they are. Adaptive radiation, as well as evolution, is discussed. The photographs, by Suschitzky, are exceptionally fine and like Huxley's text, point up each subject's outstanding characteri.^tic. There is a short section on the methods he employs in animal photography. The plates are numbered and not titled, which makes it necessary to turn back to the section titled "Notes on the Plates" to find the identifying titles and other information. This is a bit tedious but there is the advantage that the notes are not affected by space requirements. An outstanding (piality of this l)ook is that it is one that will be enjoyed by the whole family and often reviewed. Children of all ages are fascinated by the pictures and the adult members of the family must read the text to answer their questions. — Tames I). f