OMJFORNIAI FISH- GAME California Fish and Game is a journal devoted to the conser vation of wildlife. If its contents are reproduced elsewhere, the authors and the California Department of Fish and Game would appreciate being acknowledged. 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. In- dividuals 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, except regarding paid subscrip- tions, tot LEO SHAPOVALOV, Editor California Fish and Game 1416 9th Street Sacramento, California 95814 Individuals and organizations who do not qualify for the free mailing list may subscribe at a rate of $2 per year or obtain individual issues for $0.75 per copy by placing their orders with the Office of Procurement, Documents Section, P.O. Box 20191, Sacramento, California 95820. Money orders or checks should be made out to Office of Procurement, Documents Section. In- quiries regarding paid subscriptions should be directed to the Office of Procurement. u \ 1 J VOLUME 56 JANUARY 1970 NUMBER 1 Published Quarterly by STATE OF CALIFORNIA THE RESOURCES AGENCY DEPARTMENT OF FISH AND GAME STATE OF CALIFORNIA RONALD REAGAN, Governor THE RESOURCES AGENCY NORMAN B. LIVERMORE, JR., Secretary For Resources FISH AND GAME COMMISSION JAMES Y. CAMP, President, Shaffer C. RANSOM PEARMAN, Vice President Huntington Park SHERMAN CHICKERING, Member San Francisco JOSEPH RUSS III, Member Ferndale PETER T. FLETCHER, Member Rancho Santa Fe DEPARTMENT OF FISH AND GAME G. RAY ARNETT, Director 1416 9th Street Sacramento 95814 CALIFORNIA FISH AND GAME Editorial Staff LEO SHAPOVALOV, Editor-in-Chief STEPHEN J. NICOLA, Editor for Inland Fisheries CAROL M. FERREL, Editor for Wildlife HERBERT W. FREY, Editor for Marine Resources DONALD H. FRY, JR., Editor for Salmon and Steelhead HAROLD K. CHADWICK, Editor for Striped Bass, Sturgeon, and Shad Sacramento Sacramento Sacramento Terminal Island Sacramento Stockton (2) CONTENTS Page The Limnology and Productivity of Three California Coldwater Keservoirs .Stephen J. Nicola and David P. Borgeson 4 Food of Lake Trout in Lake Tahoe Ted C. Frantz and Almo J. Cor done 21 Food Habits of the Western Gray Squirrel Waltt r Stit ra ck( r and ll nice M. Browning 36 A Description of the Northern Anchovy Live Bait Fishery, and the Age and Length Composition of the Catch During the Sea- sons 1957-58 Through 1964-65 Richard Wood and Alec R. Strachan 49 A Fibroma in the Abdominal Cavity of a King Salmon, Oncor- hynchus tshawytscha _ Stanley C. Katkanski/, Ronald W. Warner, and William HSholes 60 Notes A Punch to Facilitate the Removal of Salmonid Otoliths John L. McKi rn and Howard F. Ilorton 65 A Note on the Behavior of the Octopod Ocuthoe tuberculata J a nn s E. Hardwick 68 Establishment of Tilapia mossambica Peters in Bard Valley. Imperial County. California Franklin G. Hoovi r and James A. St. Amant 70 Scrub Jay Possibly Feeding on Ectoparasities of a Black-Tailed Deer.. Terry A. Schuk and Paul D. Budwiser 71 Book Reviews 72 (3) Calif. Fish and Game, 56( 1) :4 20. L970. THE LIMNOLOGY AND PRODUCTIVITY OF THREE CALIFORNIA COLDWATER RESERVOIRS1 STEPHEN J. NICOLA and DAVID P. BORGESON 2 Inland Fisheries Branch California Department of Fish and Game Three Sierra Nevada coldwater reservoirs, Lake Spaulding and Ice- house and Beardsley Reservoirs, were studied to determine relationships between chemical and physical characteristics, primary production, zoo- plankton standing crop, and game fish yield. No direct relationships were found among these parameters. All three reservoirs are oligo- trophic, exhibiting high Secchi disk transparencies, low alkaiinities, and pH values near 7.0. Lake Spaulding had the lowest mean daily net pri- mary production (119 mgC/m2) and Icehouse Reservoir the highest (314 mgC/m2). Spaulding also had the lowest mean annual game fish yield (0.75 kg/ha), while Beardsley Reservoir was highest (6.71 kg/ha). Comparison of observed data with predicted "productivity indices" suggests that the potential yield of game fish from these reservoirs is not being realized. Lake Spaulding, because of its low temperature and high flushing rate, was lowest in overall productivity, and would benefit most from proper management activities. Net primary production, taken by itself, was not a satisfactory index to game fish yield. INTRODUCTION In 1961 the California Department of Fish and Game began a study of California's numerous coldwater reservoirs. The purpose was to find the best means of enhancing fishing quality in these waters. An im- portant portion of the study involved investigations of the limnology and productivity of three such reservoirs situated on the western slope of the Sierra Nevada : Lake Spaulding in Nevada County. Icehouse Reservoir in El Dorado County, and Beardsley Reservoir in Tuolumne County (Figure 1). The objectives of our investigations at these three reservoirs were (i) to obtain more complete basic limnological data from California coldwater reservoirs, (ii) to attempt to evaluate the characteristics of coldwater reservoirs that might affect game fish yield, and (iii) to decide whether primary production measurements would be useful in predicting game fish yield. This report summarizes the findings of these investigations. STUDY RESERVOIRS Definition of a Coldwater Reservoir In this study a coldwater reservoir is defined as an impoundment in which (i) the dominant species of game fishes are salmonids, (ii) game fish are not restricted in space for an appreciable length of time by temperature at their upper tolerance limits, and (iii) at least 50% of the maximum storage volume is the result of a man-made dam. This definition allows for the brief occurrence of surface waters of limiting 1 Accepted for publication August 1969. 2 Now with Michigan Department of Natural Resources, Fish Division, Lansing, Michigan 48926. (4) RESERVOIR LIMNOLOGY AND PRODUCTIVITY Mop Area FIGURE 1 — Map of study area, showing location of reservoirs. temperature, but is meant to exclude reservoirs with temperature con- ditions that prevent salmonids from occupying the epilimnion. The third requirement excludes impoundments that are essentially natural lakes with small dams that increase their storage capacity only slightly. Dissolved oxygen is not used as a criterion for determininir a eoldwater reservoir, for although limiting concentrations mav occur below the thermocline in relatively rich, thermally stratified waters, the tempera- ture regime might otherwise support eoldwater game fish. Characteristics of Study Reservoirs Reservoirs differ from typical eoldwater Sierra lakes in several gen- eral features. Most apparent is age. Lake Spaulding. the oldest of the three studied, was created in 1913 (Table 1 I. Sierra Nevada lakes were mostly created by glacial action, which ended about 10.000 years ago. Furthermore, most eoldwater reservoirs are considerably larger than natural lakes. Few Sierra Nevada lakes exceed 16 ha (40 acres) in surface area, whereas the majority of eoldwater reservoirs are much greater than 16 ha, and the three in this study are greater than 243 ha (600 acres). i U.II'OKVIA FISH AVI) C \ v 1 I : TABLE 1 Location and Description of Study Reservoirs Location at j River drainage . Drainage area (km*) Mean depth (m) Max. deptb (m) Max. area Cm2 x 106) Capacity mJ x 10') Mian annual Hushing rj Shoreline de\ elopn i n1 I i Year storage began Jding lat. 39 21 '\ 128 ::s'\\ \i 1 ,52 I 5 iba R. 311 34 79 2 . 73 91 .88 6 ii 2 . 30 1913 [eel I9'N 'I '\\ El 1 >orado 1,657 Silver ( 'r., trib. to S. Ik. American R. 72 21 Id 2.74 56.69 1 .1 _' . 5 1 1959 Beardaley 38°13'N 120 i'W Tuolumne 1 026 M. Fk. oislaus R. 803 16 91 2.63 120 21 3.3 2.24 1 957 1 Annual discharge 4- capacity. All three reservoirs are typical of the majority of Sierra reservoirs in their mode of operation. From the point when snowmelt runoff reaches its peak in May or June, the water level of the reservoir grad- ually declines as water is drawn off for various uses. Withdrawal con- tinues to exceed inflow until late winter (February. March), when the reservoir reaches low pool. The reservoirs experience a large annual fluctuation in water level. Spaulding has an average fluctuation of 20.0 m, Icehouse, 23.2 m, and Beardsley, 23.3 m. Generally, snowmelt runoff is sufficient to cause water to spill through the spillway. Withdrawals, however, are made through outlet structures usually located near the base of the dam. Spaulding has two outlet gates that draw water at depths of 17.0 and 48.5 m above the bottom. Icehouse ;ilso has two, located at 7 and 8 m above the bottom, while Beardsley has one, at 8 in above the bottom. Of the three reservoirs, only Icehouse lias no upstream storage or diversion structure on it-- tributaries. Beardsley lias two such structures, Donnells Reservoir 174 ha i and Relief Reservoir i 92 ha) on its prin- cipal tributary, which are used for power production and water storage. Spaulding also has two, Fordyce Reservoir 2i\ dune through November 1964, and .May through November L965; and at Spaulding from June through December 1963, April through October 1964, and dune through October L965. In addition, samples were taken once a month at Beardsley from January through April 1965 and at Spaulding From January through March 1964. Sampling was restricted to one station in approximately the center of the reservoir. On each sampling date, water samples were taken and analyzed for pll. total alkalinity, and dissolved oxygen following methods outlined in Standard Metlwds American Public Health Asso- ciation, 1965 . In addition, a temperature profile was obtained and the Secchi disk transparency was observed. Primary production was meas- ured by the C-14 method of Steemann-Nielsen 1952 . as outlined by Goldman (1963) for use in fresh water. Primary production data were analyzed with the aid of a special computer program written by gradu- ate students under the supervision of Dr. Charles K. Goldman of the Department of Zoology, University of California. Davis. California. Zooplankton Zooplankton samples were collected at the same station and on the same days that limnological data were obtained from Icehouse, from June through November 1966. In addition to the offshore station at Beardsley and Spaulding, one shallow-water (15m) station near shore was selected in both reservoirs for additional plankton sampling. Sam- ples were taken in these reservoirs also on the same days limnological data were collected, but only during August, September, and one day in October 1965. A standard Wisconsin net was used to take three vertical hauls at each station. Each sample was analyzed for total centrifuged volume, wet and dry weights, and numbers of organisms. The percent- age which each group of organisms composed of the total sample was computed and the number of each group per ni2 and per m3 was estimated. Dry weights were obtained by baking the sample in a drying oven at 50 C for 24 hr. * Catchable-sized trout are defined as those which are 71 inches (191 mm) or longer. 2 — 79574 CALIFORNIA FISH A.ND GAME Creel Census Creel censuses were conducted Prom L 962 through 1966 a1 Spaulding, from L961 through 1963 al [cehouse, and from 1962 through 1967 a1 Beardsley. At Spaulding and Beardsley two or three weekdays and both weekend days were censused each week throughoul the entire season, with Kin', and 90 to 1<>()', of the angler efforl sampled each day, respectively. At [cehouse census was conducted intermittently throughoul the season, with an unknown percentage of the angler effort sampled. Details of census methods will be presented in a later paper. Diet Stomach samples of game fish were obtained during the creel cen- suses at Beardsley and Spaulding in 1962, 1963, and l!Ki4. Stomach samples were also collected during the 1967 creel census at Beardsley. No stomach samples were collected at Icehouse. The method of collec- tion and analysis followed that recommended by Borgeson (1963). RESULTS Limnology The mean pll and alkalinities of the three reservoirs for the month of August (Table 2) closely approximated the average annual values calculated for these parameters. Surface temperatures were at their highest in July and August in Spaulding and Icehouse, and August and September in Beardsley. The highest average surface temperatures occurred in Icehouse in all months except September, when Beardsley had the highest average temperature (Figures 2, 3, and 4). Otherwise, Beardsley had the second highest average temperatures and Spaulding the lowest. High temperatures were never observed to be limiting for TABLE 2 Some Physiea! and Chemical Characteristics of the Study Reservoirs for the Month of August, All Years Combined Spaulding Icehouse Beardsley Mean temperature (C) 0 m . --- -.- 17.9 15.2 22.2 7.3 21.8 30 rn 11.6 Max. temperature « 0 in 19.1 16.0 23.1 7.4 22.7 30 m 12.6 Mean dissolved oxygen (ppm) 0 m 8.0 7.5 7.2 30 m 8.0 4.4 8.8 Mean pH 0 m . 7.1 0.7 6.8 6.1 7.2 30 m. . . 7.0 Mean alkalinity ("ppm) Orn . 10.2 8.7 8.0 7.9 22.6 30 m 20.0 Mep.n Secchi disk transparency (m) 9.9 7.2 9.2 RESERVOIR LIMNOLOGY AND PRODUCTIVITY 9 trout at anv of the study reservoirs. Thermocline formation was lacking in Spanieling Reservoir during the years of the study, at least to a depth of 30 m (Figure 2). In Icehouse, a thermocline existed from June through October at 5 to 20 m (Figure 3 i. and in Beardsley the thermo- cline ranged from 3 to 7 m from June through early September (Figure 4). Thermal stratification was strongest in icehouse. Dissolved oxygen was never sampled at a depth greater than 30 m in Spaulding or Beardsley. In all three reservoirs, however, it was pres- ent to the greatest depths sampled i Figures 2, •'!. and 4). mgC/m /Iw.ppmO, 5 10 io is eo 25 15 30 °C tiq C/m /hr, ppmOt 5 10 IO IS 20 25 mg C /mV h r .ppmO, 5 IO 15 IO IS 20 2S 30 "C mgC/mVhf.ppmOj 0 5 10 15 O S IO IS 20 25 30 °C mg C/m /nr ,ppmO| 0 5 10 15 0 5 IO IS 20 25 30 °e NET PRIMARY PRODUCTION DISSOLVED OXYGEN TEMPERATURE FIGURE 2 — Mean net primary production, dissolved oxygen, and temperature profiles of Spaulding Reservoir, 1963-65 combined (dissolved oxygen data lacking for Sep- tember and October). Although no direct measurements of turbidity were made, the study reservoirs sometimes became highly turbid in the spring and early sum- mer during snowmelt runoff. Occasional increased turbidity, of varying duration, was observed at other times of the year during and after rainstorms. Afternoon breezes, common during the summer, occasionally created turbid conditions along the shoreline through wave action. In general, Lake Spaulding tended to have the greatest Seechi disk trans- parency and Icehouse the lowest (Figure 5). Icehouse showed greatest transparency in July, while Spaulding and Beardsley were clearest in August. The greatest primary production (photosynthesis) in most months occurred in the upper 10 m, with little or no production below 20 m (Figure 2. 3. and 4). In June and July, the oxygen maxima appeared to correspond with the carbon production maxima in Icehouse. Such a relationship was not observed in other months or in the other reservoirs. In nearly all months for each reservoir, primary production was in- hibited at the surface. Depth of maximum carbon production also corresponded to the depth of the thermocline in June and July in 10 CALiniKMA. FISH AND GA^IE Icehouse, bu1 occurred in the epilimnioii in August, September, and October. In Beardsley, maximum carbon production appeared to occur always above the thermocline. The depth of maximum primary pro- duction was Less distinct in Spaulding, except in October, when it was ;it 3 in. mg C/m /hr.ppmO 0 5 10 15 O 5 10 IS 20 25 30 °C mgC/ m'/hr .ppmOj 5 10 15 10 IS 20 25 30 "C mgC/m / hr , ppm 0 5 10 15 5 10 15 20 25 30 °C mgC/m'/hr.ppmO, 0 5 10 15 O 5 10 15 20 25 30 "C SEPTEMBER mgCAi V-w ppm 0Z 0 5 10 15 0 5 10 IS 20 25 30 NET PRIMARY PRODUCTION DISSOLVED OXYGEN TEMPERATURE FIGURE 3 — Mean net primary production, dissolved oxygen, and temperature profiles of Ice- house Reservoir, 1961 and 1966 combined. mgC/m/hr, ppmOj 0 5 10 15 O 5 10 15 20 25 30 °C mgC/m /hr.ppmO 0 5 10 15 O 5 10 15 20 25 30 °C mgC/mVhr, ppm02 5 10 mgC/m /hr.ppmO, 0 5 10 15 O 5 10 15 20 25 30 °C SEPTEMBER mgC/m /hr, ppmOj 5 10 15 10 15 20 25 30 "C J I I NET PRIMARY PRODUCTION DISSOLVED OXYGEN TEMPERATURE FIGURE 4 — Mean net primary production, dissolved oxygen, and temperature profiles of Beardsley Reservoir, 1962, 1964 and 1965 combined (dissolved oxygen data lacking for October). RESERVOIR LIMNOLOGY AND PRODUCTIVITY 11 JUNE JULY AUGUST SEPT OCT 5 . I t- Q- 10 i r/ X/, \J v / SPAULDING ICEHOUSE BEARDSLEY FIGURE 5 — Mean monthly Secchi disk transparency in study reservoirs, all years combined. Production Although the "production" estimates thai were obtained at three different trophic levels in each of the study reservoirs are not directly comparable, they do help provide a meaningful insight into the rela- tionship between reservoir productivity and game fish yield (Table 3 . The average primary production values represent the total daily ne1 production of a column of water 1 m- to a depth of 30 m. This depth approximates the lowermosl depth of th<- euphotic zone in each of the TABLE 3 'Production" Estimates at Three Trophic Levels in the Study Reservoirs Mean daily net primary production and '.»■'.■ , C.I. (mgC m*)» Mean standing crop zooplankton (mg in2) b Mean annual yield game fish kg ha \ Spaulding 119 94 111 764.8 = 0.75 Icehouse 314 (276-352) 562 . 1 d 3.36 Beardsley 227 (191 - 950.6 6.71 a June through October only, all years combined. b Dry weight, to a depth of 30 m. c August and September 1965. d June through October 1966. e Wet weight (unpublished data). 12 i W.IFOKXIA PISB AND GAME reservoirs. As was expected, some variation in primary production values occurred within any one month for ;i civcn yi-.w. Vet, the mag- nitude of the differences between the reservoirs av;is large enough to Level for all months except June (Figure 6). be significant a1 the .v, 2 500 400 300 ID 5 200 I00 I JUNE JULY AUGUST ICEHOUSE BEAROSLEY SPAULDING 1 14) r> SEPT OCT FIGURE 6 — Mean daily net primary production in study reservoirs, all years combined (sample size in parentheses). daily net primary production (June through October com- •aried the most between years in Spaulding, ranging from 92 in 1963 to 142 mgC m2 in 1964 and 172 mgC/m2 in 1965. varied less between years, averaging 294 mgC/m2 in 1961 mgC/m2 in 1966. Beardsley averaged 227 mgC/m2 in 1962, 210 in 1964. and 247 mgC/m2 in 1965. The mean values for all mbined (Table 3) were significantly different from one an- Mean bined \ CI / 9 Icehouse and 326 mgC/m2 years co other A decline in net production commonly has been associated with aging in other reservoirs. Measurements in the three study reservoirs do not indicate a decline in any of them. However, the data are not extensive enough to form firm conclusions in regard to production and aging. This is especially true of Icehouse Eeservoir. since sampling in 1961 did not begin until July 12. when spring phytoplankton blooms may have passed. The main groups of zooplankters to occur in the samples from each reservoir were Cladocera : Daphnia spp.. Bosmina eoregoni, Holopediuw gibberum; and Copepoda : both cyclopoid and calanoid types, and nauplii (Figure 7). Polyphemus pediculus occurred in a small number of samples in Beardsley only and is not included. Actually, rotifers were numerically the most abundant zooplankter in all the samples; however, they did not contribute significantly to the total weight of the samples. RESERVOIR LIMNOLOGY AND PRODUCTIVITY 13 Figure 7 clearly shows that Daphnia were the most important zoo- plankters in Beardsley except in early September, when calanoids were slightly more abundant. Icehouse samples were dominated by cyclopoids and Spaulding samples by Bosmina, with Daphnia occurring in small numbers in each. The figures indicated in Table 3 for zooplankton standing crops were derived from limited sampling in but one year and must be regarded as rough estimates at best. For this reason no attempt was I oo 90 80 7 0 DAPHNIA HOLOPEDIUM BOSMINA C0PEP0D NAUPLII CALAN0ID C0PEP0DS CYCL0P01D C0PEP0DS z z U) o a. UJ Q. 50 EARLY AUGUST LATE AUGUST EARLY SEPTEMBER FIGURE 7 — Mean percentages of the most abundant groups of zooplankton (rotifers excluded) from replicate vertical hauls at offshore sampling stations. 1 \ CALIPORN] \ PISH AM) GAME liindc in li\ their reliability with confidence intervals. Nevertheless, we believe thai they provide a good relative measure of the magnitude of 'production'' for the months involved. There appeared to be no significanl difference in the numbers of each of the different organisms per m3 between the offshore and nearshore sampling stations in either Beardsley or Spaulding Reservoirs. Strong differences between res- ervoirs did occur, however, in the numbers of Daphnia, Bosmina, cyclo- poids, and rotifers per m3 a1 the offshore sampling station. It was ob- served that there was ;in inverse correlat ion in the numbers of Daphnia and HusuiiiKi between Iieardsley and Spanlding: Beardsley contained large numbers of Daphnia and small numbers of Bosmiva, while in Spaulding the situation was reversed. In these reservoirs rotifers com- prised about 50 of the samples by number, [cehouse, on the other hand, had very few of both Daphnia and Bosmina, but rotifers com- prised abonl 7.1 of the samples by number. Creel census data showed that the annual game fish yield was highest in Beardsley Keservoir (Table 3). The principal kinds of game fish harvested in the three waters included wild and hatchery-reared rain- bow and brown trout. Tn f cehouse, kokanee salmon were also important. Yield estimates for planted trout were not adjusted to account for the weight at time of planting, since this weight was negligible. The yield of game fish varied from 0.69 to 0.87 kg/ha in Spaulding and from 2.99 to 9.84 kg/ha in Beardsley. The estimated 3.36 kg/ha for Icehouse is based on 1962 data only. Tn Beardsley, the average annual catch composition by weight was 95.2 \ rainbow trout and 4.8% brown trout, while for Spaulding the percentages were 75.2 and 24.8, respectively. In 1961, before the introduction of kokanee, the per- centage harvest by number of rainbow trout and brown trout in Ice- house was 90.9 and 9.1, respectively. In 1962. following the introduc- tion of kokanee, the percentages were 76.5 rainbow, 17.8 kokanee, and 5.8 brown trout. Apparently the kokanee predominated in subsequent years, for in 1963 the catch percentages had shifted to 77.4 kokanee, 13.6 rainbow, and 9.1 brown trout. Presently, however, wdld trout production in Icehouse is not sufficient to satisfy fishing demands and "eatehable" rainbow and brown trout are planted throughout the fishing season, while fishing for kokanee, supported mainly by plants of fingerlings, occurs principally during May and June. Diet In both Beardsley and Spaulding it was found that cladocerans, principally Daphnia, were the only zooplankton eaten by rainbow trout (Figure 8). The diet of the rainbow trout in the two reservoirs was strikingly different. In Beardsley, zooplankton comprised almost the total volume of food for all sizes of rainbow to 432 mm (17.0 inches), with terrestrial organisms composing the second largest food group. In Spaulding, on the other hand, zooplankton rarely entered the diet of rainbow of any size. Terrestrial organisms and aquatic invertebrates (other than zooplankton) were predominant in the diet of trout to 356 mm (14.0 inches), while fish (primarily Hypomesus) assumed greater importance for rainbow larger than 356 mm. On a monthly basis, the rainbow trout food pattern in Beardsley differed little from the situa- tion indicated by Figure 8. Terrestrial organisms comprised a greater RESERVOIR LIMNOLOGY AND PRODUCTIVITY 15 part of the rainbow diet in June for fish larger than 279 mm (11.0 inches) than in any other month. The situation was somewhat more variable in Spaulding, with aquatic invertebrates and fish predominant 100 50 - 0 - 100 . 50 BZOOPLANKTON AQUATIC INVERTEBRATES TERRESTRIAL ORGANISMS FISH < 432 MM < I- O z Id U a. 0. 0 100 356 - 429 MM 50 100 50 279 - 353 MM 5277 MM -d BEARDSLEY SPAULDIN6 FIGURE 8 — Relative abundance of food items of four size groups of angler-caught rainbow trout from study reservoirs, 1962-64. Iii i OjIPORN] \ FISH and <;\ ME in May and Augusl and terrestria] organisms predominant in June and -I uly. In Spaulding, brown troul larger than 279 nun fed almosl exclu- sively on Hypomesus. Brown troul smaller than this were not sampled. since brown troul were only occasionally taken in Beardsley, few stomach samples were obtained, bu1 these indicated a piscivorous diet. The piscivorous diet of brown troul in lakes is well known. Although nn food consumption data are available from [cehouse Reservoir, it is reasonable to assume that kokanee led almost exclusively on zooplankton, as they do in most lakes (Seeley and McCammon, 1966). Too few stomach samples of nongame fish from Beardsley and Spauld- ing were taken to permit a quantitative analysis of their food habits. Some qualitative observations of stomach contents were possible, how- ever. In Beardsley, Catostomus fed mostly on bent hie invertebrates, mainly aquatic insect larvae and nymphs, while Lavinia ate not only bent hie invertebrates but cladocerans as well. In Spaulding, Ptycho- cheilus fed on a variety of aquatic invertebrates as well as zooplank- ton. Hypomesus was not sampled but it is believed to feed primarily on zooplankton (Wales. 1962). DISCUSSION I 'sing the terminology developed for natural lakes (Hutchinson, 1957), it appears that all three reservoirs are most nearly like second- class dimictic lakes, with Spaulding possibly approaching one of the third-class type. The oxygen profiles in Spaulding and Beardsley resem- ble orthograde curves, while Icehouse oxygen profiles are of the posi- tive heterograde type. All three reservoirs may be considered oligo- trophy, or nutrient-poor. On the basis of the data presented in Table 3, it appears there is no direct relationship between primary production, standing crops of zooplankton. and annual yield of game fish. Given the type of data collected and the complexity of interrelationships among the orga- nisms of the different trophic levels, this is not surprising. Obviously, it would be a great advantage to fisheries managers if the relationship between the reservoir's basic productivity and game fish production could be clearly defined. Although our data are not complete enough to define these relationships precisely, we can make some reasonable evaluations of the factors that affect game fish yield in coldwater reservoirs. The ultimate factor which determines the potential yield of game fish in a reservoir is the capacity of the primary producers to manu- facture food materials that can be used by heterotrophic organisms (i.e., net primary production). The actual yield of game fish, assuming a stable fishery, is dependent on a host of factors that fall into two categories: (i) factors that affect primary production, and (ii) factors that affect the transfer of food material after it is produced. The former includes the supply of nutrients, temperature, light penetra- tion, other chemical and physical variables, the flushing rate, and the abundance and composition of the phytbplankton. The latter includes the number of trophic pathways between phytoplankton and game fish. RESERVOIR LIMNOLOGY AND PRODUCTIVITY 17 and the direction and efficiency of energy transfer within and between trophic levels. Murphy (1962) states thai for a reservoir to have good productivity mi epilimnion must be present, the turbidity must be Low, and there must be some degree of mixing with the nutrient-rich hypolimnion. In Spaulding, with the lowest ne1 primary production, an epilimnion failed to form from June through October, at leasl to the depth where primary production occurred. Furthermore, the average temperature to a deptli of 10 m from duly through September was somewhat lower than in Beardsley or Icehouse. Efford (1967) found a (dose relationship between primary production and temperature in .Marion Lake. British Columbia, and Sparrow (1966) noted a direct relationship between mean epilimnion temperature and zooplankton abundance. Thus, tem- perature appears to correlate directly with the observed primary pro- duction. However, more than temperature is involved. In October the temperature of both Icehouse and Spaulding is nearly identical (Fig- ures 2 and 3), ye1 primary production in Icehouse is about twice as greal as in Spaulding ( Figure 6 . Another factor which correlates directly with the observed ne1 pri- mary production is the flushing rate (the number of times a volume of water equal to the storage capacity of the reservoir passes through the reservoir each year'. The effed of a high flushing rale is to retard the rate of nutrient accumulation (eutrophication) in the reservoir. Flushing, of course, occurs in natural eoldwater lakes but usually at a much slower rate than in mosl reservoirs. Efford (1967) believed that it was not as important as temperature in limiting productivity in Marion Lake. II would also tend to (lush out phytoplankton populations if the outflow occurred at or near the surface. The effed of nutrient removal would be most critical in reservoirs with outlet structures that draw water from the nutrient-rich hypolimnion (Murphy. 1962; John- son and Berst, 1965). This situation exists for each of the three study reservoirs. The flushing rate for Spaulding (Table 1) is considerably higher than for either Icehouse or Beardsley and may be a significant factor affecting primary production. Alkalinity failed to correlate directly with the observed primary production for each of the reservoirs. However, Carlander (1955) and Movie (1956) found positive correlations between standing crops of fish and alkalinity concentrations in lakes which they examined. The available nutrients were not measured nor were limiting factor (trace element) bioassays (Goldman. 1962) conducted, so it is not possible to say to what degree nutrients were limiting the primary production. It is possible that the species composition and abundance of the phytoplankton populations in the three reservoirs was distinctly dif- ferent and could have led to the difference observed in net primary pro- duction and zooplankton standing crop. Wright (1960) showed that the relationship between photosynthesis and phytoplankton standing crop is not linear. Bather, be found that net photosynthesis was maximal at intermediate levels of standing crop and less at concentrations above the intermediate range. Unfortunately, however, these variables were .not evaluated in the present study. 18 <■ LLIPORN] \ PISH \M> CAME The lack of correlation between phytoplankton production and zoo- plankton standing crop and game fish yield may be explained by i samining some of the factors which affect the transfer of energy through the trophic levels. Few game fish are adapted to feeding directly on such tiny organisms as phytoplankton and tin* game fish in these reservoirs are no exception The rainbow trout rely heavily on zooplankton in Beardsley, which has a much greater zooplankton standing crop than Icehouse. A likely explanation Bor the observed differences iii primary production and zooplankton standing crop be- tween Icehouse and Beardsley is that the kokanee, predominant in Icehouse, are very efficient plankton feeders. The lack of larger forms of zooplankters in [cehouse suggests that kokanee grazed upon these organisms quite heavily. A depressed population of zooplankters, in turn, would lead to a reduced rate of grazing on the phytoplankters, which could result in a larger population of phytoplankton and pos- sibly a higher rate of primary production. In Beardsley, grazing by the rainbow trout on zooplankton was less severe than grazing by the kokanee on zooplankton in Icehouse. The resultant rate of grazing by the zooplankton on the phytoplankton was then much greater, con- tributing to a depression of the expected rate of primary production. The difference in annual yield of game fish between Icehouse and Beardsley may be due to the fact that rainbow trout in Beardsley are more efficiently harvested than the kokanee in Icehouse. Kokanee are quite restricted in their distribution for most of the fishing season, and most anglers lack the knowledge of how to fish for them (Seeley and McCammon, 1066). If they were more readily available to fishermen, it is probable that the yield of game fish in Icehouse would have been greater. Although Lake Spaulding had the lowest primary production and game fish yield, it was intermediate in zooplankton standing crop. Generally, it is usually the larger macroscopic cladoeerans which con- tribute the bulk of the total volume and weight to a sample of zoo- plankton. Thus, in Beardsley. where the larger Daphnia were dom- inant, the greatest standing crop occurred, while Spaulding, where the smaller Bosmina were most abundant, had the second highest standing crop. In Icehouse, however, cladoeerans of any kind were relatively scarce, and its zooplankton standing crop was lowest. It is obvious that the data pose more questions than they can answer about the production relationships in these reservoirs. It appears, how- ever, that Spaulding Reservoir, with the lowest game fish yield, also has the lowest overall productivity of the three reservoirs studied, with Icehouse and Beardsley substantially higher and more nearly equal in overall productivity. The primary reasons for these differences are that Lake Spaulding (i) lacks a shallow epilimnion with only a weak, deep thermocline, if any exists at all. (ii) has substantially lower average temperatures in the euphotic zone, and (iii I has a very high flushing rate. Conditions in Icehouse and Beardsley are quite the opposite and are more conducive to higher productivity. Productivity Indices For a number of years biologists have attempted to correlate various physical, chemical, and/or biological characteristics of lakes with fish RESERVOIR LIMNOLOGY AND PRODUCTIVITY 19 production. In addition, some have used these characteristics to derive indices of general "productivity'' (Movie, 1946; Rounsefell, 1946; Carlander, 1955; Hayes and Anthony. 1964; Ryder, 1965). Hayes and Anthony, using data from lakes of the midwestern and eastern U. S., incorporated methyl orange alkalinity, area, and depth into a multiple regression equation which was used to derive a "productivity index". They believed that their equation accounted for an estimated 67% of the variability in the index in which 20' '< was due to area, 29% to depth, and 18^? to alkalinity. When our data were fitted to their equation we obtained predicted productivity indices of l.!». :>..">, ;md 2:2 for Spaulding, Icehouse, and Beardsley, respectively. These were compared to the observed produc- tivity indices of 0.1'. 0.7. and l.-'i derived by dividing the actual annual yield of fish by the expected annual yields (Hayes and Anthony, 1964, p. 5:{. 54. Tables 1 and 2 ) . The ratios of the observed productivity index to the predicted productivity index for Spaulding, Icehouse, and Beardsley were 0.08, 0.21, and 0.59, respectively. Assuming that their equation is valid, the fad that these ratios are less than l.o sug- gests that the yield of game fish from the study reservoirs is not com- mensurate with that expected from their predicted productivity in- dices. This would seem especially true in Icehouse and Spaulding, where the deviations are Large. These results indicate thai there is room for improvement in managing these waters for optimum harvest of game fish. Spaulding, it appears, could benefit the most from proper management activities, with Icehouse next. Beardsley, theoretically, has the least room for improvement, being closer to the predicted value than the others. Primary Production As we observed, there was no direct correlation between net primary production and game fish yield. In light of the complexity of factors affecting game fish production, as discussed above, tins is not un- expected. Rupp and DeRoche (1965) also failed to correlate net pri- mary production with standing crops of fishes in three Maine trout lakes. It is highly unlikely that, in any but the simplest of situations, net primary production will ever correlate directly with game fish production. It may, however, be a valid means of assessing a reservoir 's "potential" for producing game fish. Securing accurate estimates of net primary production by the complex C-14 method, however, would require more time and effort than would be practical in a routine management program. ACKNOWLEDGMENTS Don A. LaFaunce, Robert C. Tharratt, and WihLiam R. McAfee were responsible for collecting most of the limnological data. We are grateful to Dr. Charles R. Goldman. Evelyne cle Amezaga, and Pierre Kleiber of the Institute of Ecology, University of California, Davis, for provid- ing assistance in processing and analyzing the primary production data. Almo J. Cordone, California Department of Fish and Game, and Dr. Robert W. Brocksen. Department of Physiology, University of Califor- nia, Davis, reviewed the manuscript and rendered valuable criticisms. 20 l ILIFORNIA PISH AND GAME The cooperation of Eugh \l. Daniels. Pacific (ias ;md Electric Com- pany, Paul Shaad, Sacramento Municipal Utility District, and A. C. Eolbrook, Oakdale Irrigation District, in providing physical and hydro- logical data for Lake Spaulding and [eehouse and De.irdsley Reser- voirs, respectively, is gratefully acknowledged. REFERENCES American Public Health Association. 1965. Standard methods for the examination of water and wastewater including bottom sediments and sludges, 1-th Ed. A. P. II. A. Inc., New York, \\\i - 700 p. Borgeson, David P. L963. A rapid method for food habits studies. Trans. Anicr. Fish. Soc, 92 (4) : 134 135. Carlander, Kenneth D. L955. The standing crop of fish in lakes. Jour. Fish. Res. Bd. Canada, 12 (4) : 543-570. Efford, Ian E. 1967. Temporal and spacial differences in phytoplankton productivity in Marion Lake. British Columbia. Jour. Fish. lies. Bd. Canada. 24 (11) : 2283-2307. Goldman, C. R. 1062. A method of studying nutrient limiting factors in situ in water columns isolated by polyethylene film. Limnol. and Oceanogr., 7(1) : 99— inl. — . 1963. The measurement of primary productivity and limiting factors in freshwater with carbon-14, p. 103-113. In M. S. Doty [ed.J Proc. conference on primary productivity measurement, marine and freshwater, U. S. Atomic Energy Commission, TID 7633. I Ia.\es. F. R.. and E. II. Anthony. 1964. Productive capacity of North American lakes as related to the quantity and the trophic level of fish, the lake dimensions, and the water chemistry. Trans. Amer. Fish. Soc, 93 (1) : 53-57. Hutchinson, G. Evelyn. 1057. A treatise on limnology, Volume 1: geography, physics, and chemistry. John Wiley and Sons. Inc., Xew York, xxi + 1015 p. Johnson. M. G., and A. II. Berst. 1005. The effect of low-level discharge on the sumnier temperature and oxygen content of a southern Ontario reservoir. The Canadian Fish Cult., 35 : 59—66. Movie, John B. 1946. Some indices of lake productivity. Trans. Amer. Fish. Soc, 70 : 322-334. — . 1050. Relationships between the chemistry of Minnesota surface waters and wildlife management. Jour. Wildl. Mangt., 20 (3) : 303-320. Murphy, Garth I. 1002. Effect of mixing depth and turbidity on the productivity of fresh-water impoundments. Trans. Amer. Fish. Soc, 91 (1) : 69-76. Rounsefell, George A. 1946. Fish production in lakes as a guide for estimating production in proposed reservoirs. Copeia, 1(1) : 29—40. Rupp, Robert S., and Stuart E. DeRoche, 1965. Standing crops of fishes in three small lakes compared with C-14 estimates of net primary productivity. Trans. Amer. Fish. Soc, 04 i 1 i : 9-25. Ryder, R. A. 1905. A method of estimating the potential fish production of north- temperate lakes. Trans. Amer. Fish. Soc. 04 (3) : 214-218. Seeley. Charles M., and George W. McCammon. 1966. Kokanee, p. 274-294. In Alex Calhoun [ed.] Inland fisheries management, Calif. Dept. Fish and Game. Sparrow. R. A. H. 1966. Comparative limnology of lakes in the southern Rocky Mountain Trench, British Columbia. Jour. Fish. Res. Bd. Canada, 23 (12) : 1875-1895. Steemann-Nielsen, E. 1052. The use of radioactive carbon (C14) for measuring organic production in the sea. Jour, du Consiel Internatl. Explor. Mer, 18 : 117-140. Wales. Joseph H. 1902. Introduction of pond smelt from Japan into California. Calif. Fish and (lame. 4s (2) : 141-142. Wright, John C. 1960. The limnology of Canyon Ferry Reservoir : III. Some obser- vations on the density dependence of photosynthesis and its cause. Limnol. and Oceanogr., 5 (4) : 350-361. Calif. Fish and Game, 56(1) : 21-35. 107, ■^ ic ao IC 1^- — TJ — — OJ ■~ ~ r in X CM — t - U3 Ol _c X •-H CM 00 EC < — »-T, -jr -^ 1^ o — — pa — I - x 7 f - i^- — "^ ■ - GO x r- ^ 3 Z 2 X 71 Tl — s . - - i o — o — — r. re M n a . — — _ «-- in OB : CI T< en a. Z Im - > -3 X x - 1- o Z 0 1 - ci 1*3 OO o ,0 *C I- e CO r^ .-= ■ . — r - CM is - n i - — - i - CM Z CM at) — •o CO o> re »C « en ri TJ - 3 CO ™ U9 CM 2 s C5 z " _. - ■C — ^ *o T3 — — — g ■s r- x • r - — ■ r - ee re en S 9 * DC re E z TJ * * CD ro TJ i - ^ co >. / O o 3 TT *a C a ; CO t^ -i CO CM ~~ v. i - • M ~. CM — , ci re C) irt ~- ■2 a ao oo x CO — ' . i>H DO tf?. — o is o Z ua re in = t- re r CO >. c — — re 1 — •- c [S _ „ — in c ^ Z — „ I- a T IC o CO i~ :/: — CO 1 — jC *j t^ — eo _ CO ■s a M * — 0 M re r- >> ^ c; a 30 — co 4A Q — — — CM d ■c * £ ~t3 3 a t^ r~ CO £d — a 6? 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". ~ t3 1 g C = ■ g ! S • s 8 E cc '5 1 C ~ ■ — DO "Jg ~ ;- = ~ 1 1 r 0 5 ^ g 3 , -— ^ _S _x 93 3 « . ^ - - £ - - - - c B6 ~ '*— i = ~ JZ Z — '*- -l^~ I - y- - .- 1 - ; : U 5 r i| 1 -§ li 3 <■ ~ ~ '•- ■ I I .= -7. 4 d 1 /. a K g § i : c g ' ""■ Ti 1 5* — *- X - .L. - ^ — — ~ ~T e ~x — r- r" h^ z 2~.Z^ I w Z- *~- W f — — I ^ .5 X z — fe u .— »!_,-* Dj o -3 _2 "3. 73 P3 c o -^ &O -t-3 Q t- HO h ■+=» O _ - ~ B S OT3 3». C— c Z zz ■8 'rX =! . "3 ^ rt _* 2 - ire 1H o flJS ® ° ^ c S3 - •f. r - :. (- IS — - ~~~ 5* — — :. 0 - - D9 = i- - > — — < — FOOD OP LAKE TROUT 20 in Tahoe (Frantz and Cordone, 1966), but were rarely encountered in lake trout stomachs. No fish were found in stomachs of this group. Lake Trout 5.0 to 9.9 Inches Cladocerans and fish were the most important items in the diet of lake trout in this size group (Table 2). The only species of fisli ingested was the seulpin. The highesl Dumber in any one stomach was four, with a total weighl of 1.46 g. Other foods contributed much less to the diet, comprising approximately IT, of the total weight. Tendipedid larvae and pupae were present in 21', of the stomachs, hut contrib- uted only ].'■'>', by weight. A maximum of »i<; tendipedids occurred in (»ne trout, where, is ;i record 426 plecopterans occurred in another stomach. Amphipods were much more importanl to lake trout in this size range than to those in other size categories. The number of amphi- pods per stomach ranged from 2 to I!*."). Ostracods and fish eggs were insignificant. Lake Trout 10.0 to 14.9 Inches Fish and cladocerans remained the major food types within this group (Table 2). One 13.8-inch hike n-out had ingested over ::..")iii) cladocerans with ;i weighl of 2.8 ■_:•. A greater variety of food types was found in these hike trout, particularly the differenl species of fishes. SculpinS fill' exceeded other species (if tislles ill tile diet of hike tfolll in this group. Single stomachs contained ;is many ;is nine sculpins. Lake trout and suckers were utilized to a moderate degree, while chubs, redsides, and whitefish were of lesser importance. Tendipedid larvae and pupae were found in 12.7', of the stomachs, hut contributed little to the overall weight. Crayfish appeared for the first time in the stom- achs of these fish and occurred as frequently as lake trout. Fish eggs, amphipods, oligochaetes, and terrestrial insects were taken only occa- sionally. Lake Trout 15.0 to 19.9 Inches The consumption of fish overshadowed all other food items of lake trout in this size range (Tahle 2). Cladocerans. which were very im- portant in the smaller size groups, occurred frequently in stomachs of trout in this group, hut contributed little to the weight of stomach contents. Sculpins were the most important food in this group. Large numbers were occasionally present, with one stomach containing 40 sculpins. The average number in stomachs containing them, however, was 2.9. (»ther fish species were also important, with suckers and chubs com- prising a large proportion of the stomach contents. The number of suckers or chubs found in any one stomach did not exceed four. AVhite- tish were fourth in importance and trout, other than lake trout, were next. Most of the trout were planted rainbow and cutthroat trout. Lake trout, kokanee, redsides. and dace were only a minor component of the diet. Crayfish were the third most important food. Forage items of minor consequence were fish eggs and invertebrates other than cladocerans and cravfish. 26 I \I.H"K\!\ FISH AND GAME Lake Trout Over 19.9 Inches Lake trout in this size group relied almost entirely on fish for their sustenance (Table 2 . Suckers comprised the greatest proportion of the food items. The greatesl number of suckers found in any one stomach was six. Sculpins were second in frequency of occurrence but represented a minor proportion of stomach contents by weight. In several instances, however, large numbers were eaten by individual trout: one 23. 7-inch troul had consumed 31 seulpins. The average number of sculpins per stomach was 2.9. All fish species, except dace and redsides, were important in the diet of these l;irc-e lake trout. Wli itefisli. chubs, and kokanee salmon con- tributed significantly to the diet of trout in this size group. Lake trout weiv eaten occasionally, with nine stomachs each containing one fish. Trout, other than lake trout, were important also. These consisted of planted and wild rainbow. Lahontan cutthroat. Yellowstone cutthroat, and unidentified Salmo which may have included brown trout. Virtually all trout stocked in the lake were marked and when digestion was only moderate such fish could be identified (Cordone and Frantz, 1968). Lake trout appeared to feed heavily on these planted trout. Gill nets were not generally set close to the area where trout were stocked, except for one set in June 1062 off Tahoe City in 40 ft of water two days after a release of Lahontan cutthroat. Stomachs of 8 lake trout that were caught contained 74 cutthroat. In another area, close to where Yellow- stone cutthroat were released, three stomachs of angler-caught lake trout each contained from four to nine cutthroat. Crayfish were the only invertebrate of consequence to appear in the diet of the largest lake trout. They were the third most important food, occurring in 17.1% of the stomachs. Fish eggs occurred infrequently. Seasonal Variation The percentage of lake trout stomachs with food was highest in spring and summer and lowest in winter and autumn 'Table 1). Similarly, the mean weight of food per stomach for all size groups was generally highest in spring and summer and lowest in winter and autumn. Because of few samples, the two smallest lake trout size groups were combined for the seasonal food habits analysis (Table 3). Lake trout under 10.0 inches utilized sculpins most avidly in the spring. Clado- cerans were important during all seasons but particularly in winter, and to a lesser degree in summer. Amphipods and stoneflies were sig- nificant only in summer. Tendipedid larvae were consumed primarily in spring and to some extent in winter. Their pupae were most common in summer. Seulpins also were most important for 10.0- to 14.9-inch lake trout in the spring months (Table 4). The greatest variety of fish was eaten in autumn, with spring second. Cladoeerans were an important com- ponent of the diet during all four seasons, but especially in winter and summer. Crayfish were found in less than 6% of the stomachs from spring through autumn. Tendipedid larvae were consumed throughout the four seasons but most frequently in winter and summer. Their pupae were most common in summer and somewhat less common in FOOD OF LAKE TROUT 27 TABLE 3 Percentage Frequency of Occurrence and Percentage of Total Weight of Food in Stomachs of Lake Trout Under 10.0 Inches, by Seasons Season Winter Spring Summer Autumn Number of stomachs with food 10 16 17 17 Items Fre- quency (%) Weight (%) Fre- quency (%) Weight (%) Fre- quency (%) \\ eight (%) Fre- quency (%) Weight Piute sculpin 6.2 93.7 0.2 1 2 . 5 12.5 6.2 58.7 34.8 0.3 .">. t 5.4 0.8 31.2 56 -' 6.2 37 . 5 ;;7.:, 61.1 38.0 0.0 0*9 0.8 0.0 5.9 70 6 17. 6 5.9 11.8 17.0 37.7 21. 1 17.2 0.3 0.1 0.2 23. 1 11.8 5.9 64.7 11.8 .". . 9 5.9 50.5 Fish eggs 2.4 CruMueea C'ladocera1 16.5 0.5 Tendiprdidae 0.1 Pupae 0.1 Plecoptera Oligochaeta Mean weight (g) per stomach 0 2 0 6 0 3 0 2 1 Includes copepods. TABLE 4 Percentage Frequency of Occurrence and Percentage of Total Weight of Food in Stomachs of Lake Trout 10.0 to 14.9 Inches, by Seasons Season Winter Spring Sum mer Autumn Number of stomachs with food 11 53 3 5 51 Items Fre- quency (%) Weight (%) Fre- quency (%) Weight (%) Fre- quency (%) Weight (%) Fre- quency (%) Weight (%) Fish (total) --- 27.3 18.2 9.1 9.1 81.8 27.3 27.3 .-,2.:: 48.8 3.1 0.3 46.7 0.9 0.9 r.4 . 7 43.4 1.9 3.8 5.7 3.8 56.6 .",.7 13.2 7.5 7.5 1.9 70.0 53.6 2.4 2.4 11.6 0.0 24.1 2.6 0.1 0.0 0.0 3.1 37.1 25.7 2.9 8.6 74.3 2.9 2.9 22.9 17.1 11.4 2.9 34.2 21.1 9.9 3.1 54.4 0.8 0.4 0.5 0.4 0.2 9.6 39.2 21.6 7.8 2.0 3.9 2.0 5.9 5.9 66.7 2.0 2.0 2.0 65.7 Piute sculpin .. 35.5 Tahoe sucker. 19.0 Tui chub 0.3 Lahontan redside 4.1 Mountain whitensh Unidentified fish Fish eggs _ _ . . 6.2 0.6 14.4 Crustacea Cladocera 17.8 Amphipoda - _. Crayfish 2.1 0.0 Larvae 0.0 Pupae Terrestrial insects. ._ .. Oligochaeta -- Mean weight g> per stomach 0 8 1.6 0 6 1 4 28 ( \i.[|-oi;\i \ i-isii and (i \ mi: s|ii-in<_r. Other invertebrates were taken seasonally: amphipods and oligochaetes in summer and terrestrial insects in spring. Must species of tishes encountered in the stomachs of 15.0- to 19.9-inch lake troul were present cadi season (Table 5). Spring continued to be ilii' period when sculpins contributed the most, occurring in 53.6% TABLE 5 Percentage Frequency of Occurrence and Percentage of Total Weight of Food in Stomachs of Lake Tahoe Lake Trout 15.0 to 19.9 Inches, by Seasons -.:t~.>n Winter Sprint: Summer \utumn Number of stomachs with fond 83 237 136 203 Items Fre- quency (%) Weight (%) Fre- quency (%) Weight (%) Fre- quency (%) Weight (%) Fre- quency (%) Weight (%) Fish (total) 63 . 9 32 . 5 3.6 8.4 2.4 2.4 1.2 3.6 10.8 12.0 47.0 7.2 12.0 12.0 1.2 4.8 90.2 14.3 24.9 16.6 0.1 1.1 0.0 7.2 24.2 1.6 2.0 7.5 0.3 0.3 0.0 0.0 73.8 53 . 6 ."). 1 10.5 2.5 0.8 2.1 2.9 2.5 3.4 9.3 34.2 9.7 13.5 3.4 11 .4 1.3 91.3 35.4 14.0 9.4 3.7 0.0 2.0 15.9 3.0 6.0 1.3 2.2 6.1 0.2 0.0 0.2 0.1 58.8 41.2 6.6 6.6 1.5 2.2 3.7 0.7 2.2 7.3 40.4 0.7 0.7 21.3 16.2 10.3 13.2 0.7 0.7 76.4 17.9 23.0 12.0 0.6 2.3 11.4 0.3 8.2 0.7 1.6 0.0 0.0 21.8 0.1 0.1 0.1 0.0 0.0 59.6 21.2 11.3 11.8 2.0 1.0 1.0 1.0 10.8 12.3 3.4 37.9 0.5 12.3 3.0 3.0 0.5 0.5 81.3 Piute sculpin . - __ 10.3 Tahoe sucker .. Tui chub l.:ili(intan redside. Lahontan speckled dace _. 17.6 22.1 1.5 Lake trout 1.6 Other trout. 0.4 Kokanee salmon Mountain whitefish Unidentified fish Fish eggs . _ Crustacea Cladocera Ostracoda Amphipoda 3.8 22.2 1.7 5.2 1.7 0.0 Crayfish 11.7 Tendipedidae Larvae Pupae 0.0 0.0 0.0 Plecoptera Terrestrial insects. 0.0 Mean weight (g) per stomach 3 7 5 9 6 6 5.1 of the stomachs. Whitefish were equally important in winter and autumn, occurring in about 10.8%. The number of stomachs containing suckers increased from winter to autumn, whereas by weight the per- centage was greatest in winter and summer. Chubs occurred in the diet most frequently in spring and autumn. Cladocerans occurred in 34 to 47 ','< of the stomachs during all seasons, but constituted only about 2% of the stomach contents by weight. Occurrence of crayfish increased from a low of 7.2% in winter and 9.7% in spring to a substantial 21.3% in summer, followed by a decrease to 12.3% during autumn. Tendipedids contributed little weight to the lake trout diet ; however, larvae were taken frequently in winter and summer, and pupae in spring and summer. Other organisms were of minor im- portance, with ostracods occasionally taken in summer, amphipods in FOOD OF LAKE TROUT 29 summer and autumn, stoneflies in winter and summer, and terrestrial insects from spring through autumn. Seasonal food habits of lake trout over 19.9 inches consisted pri- marily of fish, with crayfish of secondary importance (Table 6). Suckers TABLE 6 Percentage Frequency of Occurrence and Percentage of Total Weight of Food in Stomachs of Lake Tahoe Lake Trout Over 19.9 Inches, by Seasons Season Winter Spring Summei Autumn Number of stomachs with food 26 79 40 77 Items Fre- quency Weight Fre- quency Weight Fre- quency \\ eight 1 re- quency \\ eight 1 i-l. total) Pillti sculpin 96.1 34.6 18 5 11..-. :; 8 7.7 11.5 23 . 1 23 . 1 11.5 3.8 96.7 5.9 59 8 2.4 0.6 15.7 10.8 0.7 : ■ 0.0 93.7 n :; 32.9 8.9 3.8 7.6 i ; 9 7.6 5. 1 5.1 1.3 1 5 . 2 96.9 S.4 38.0 7.7 ().:, 2.1 33.7 3.7 2. 1 0.4 0.0 3.1 85 (i 22 . 5 12 5 12.5 _' 5 7.:. 17.:. 30 0 :, 0 80.3 1 .0 65.9 6.5 0.8 0.8 19 8 87.0 11.7 24 7 1 9 . 5 1 :; 1.3 6.5 18.2 20.8 3.9 2.6 14.3 87.6 0.6 Tahoe sucker 18 i Tui chub 6.9 Lahontan redside Lake trout . 0.2 i >ther Hunt Kokanee salmon Mountain « hitefiah I aidentified fish _ _ . l'isli eggs. ll 1 4.8 35.5 0.8 0.0 ( 'rustacea ( lladocera. 0.0 Crayfish Tendipedidae larvae l'lecoptera - ii'.:; Mean weight gi per stomach 14 9 48 5 37 1 27 4 were the most common food item in all seasons except spring, when more sculpins appeared. The weight of suckers, however, clearly exceeded that of any other species in all seasons. ( fccurrenee of suckers was high- est in summer and lowest in autumn. Sculpins occurred most frequently in spring and winter, and less frequently in summer and autumn. White- fish were important in winter and autumn, but were unimportant in spring and absent in summer. The percentage of stomachs with chubs was highest in autumn. Kokanee salmon were found in 11.5% of the stomachs in winter, and gradually decreased from spring through autumn. Lake trout and ''other" trout were more prevalent in lake trout stomachs during spring. The occurrence of "other" trout during this period is largely due to predation on planted Lahontan and Yel- lowstone cutthroat in May and June of 1962. Spring was the only period when a few stomachs contained redsides. As in the diet of smaller lake trout, fish eggs occurred only in a few stomachs and only in autumn. Because of their size and their appearance in autumn only, it seems likely that these were lake trout eggs. Whitefish eggs are much smaller, and beach spawning of kokanee salmon was extremely limited when the study was made. Consumption of crayfish during the summer was second to that of suckers. Other invertebrates were unimportant. 30 CALIFORN] \ Fisll AND GAME Size of Fish Eaten A.s anticipated, the larger lake troul consumed larger prey (Table 7 . Suckers and whitefish 9 to 11 inches long were not uncommon in the stomachs of 20- to 25-inch lake trout. Although not part of this study. ;i 34-inch (in. 2 Ih - hike troul caughi in 1961 contained a 16.5- TABLE 7 Mean and Maximum Lengths of Fish and Crayfish Ingested by Lake Tahoe Lake Trout, by Size Groups Size group inches kli 5.0-9.9 10.0-14.9 15.0-19.9 Over 19.9 Item No. Mean length Max. li-iiL'th Xo. Mean length Max. length No. Mean length Max. length Xo. Mean length Max. length Piute sculpin . Tahoe sucker Tui chub Lahontan redside Lake trout < )ther trout Kokanee salmon Mountain whitefish Crayfish, . 9 1.9 2.3 57 4 2 5 1 2 1.9 3.1 1.9 2.8 3.7 1.6 3.1 3.8 2.9 3.0 3.7 1.8 454 27 38 8 7 13 3 23 44 2.0 4.4 3.5 3.1 4.3 5.0 3.9 4.7 2.3 4.2 7.8 5.8 3.8 6.4 6.0 4.5 7.1 4.2 116 38 15 2 4 15 6 9 46 2.4 6.4 4.3 3.4 5.0 4.8 5.6 8.6 2.9 4.1 11.5 9.5 3.4 7.5 7.1 7.3 11.9 4.3 inch lake trout. Corlett and Wood (1958) describe a 36-ineh lake trout which had eaten three fish, one of which was at least 19 inches long. The smallest lake trout with fish was a 5.2-inch specimen which had eaten a 1.3-inch sculpin. DISCUSSION Comparisons with Previous Tahoe Studies The two previous studies on food of lake trout in Tahoe by Miller (1951 i and Corlett and Wood (1958) were compared with the present study. Miller obtained 191 stomachs from May through September in 1948 and 1949. They were taken from fish 9 to 32 inches fl, but most were from fish over 15 inches. During- their study from 1954 through 1958, Corlett and Wood collected 386 stomachs from lake trout rang- ing from 14 to 36 inches fl. Of these. 255 contained food and the con- tents were evaluated only by percentage frequency of occurrence. For comparative purposes, results of these two studies were compared with food habits of lake trout over 14.9 inches from the present study. In all studies, fish were by far the most significant food, with the sculpin the most common of the fishes (Table 8). Miller lists the chub as the second most common food and the sucker as the third in fre- quency of occurrence. The occurrence of bottom food was fourth. Miller stated. "Among the bottom foods the only form of note is the crayfish. . . . ". Those of lesser importance and in decreasing order were redsides, plankton, surface food, whitefish, and lake trout. Miller found that the suckers contributed the greatest percentage by volume, followed closely by chubs and sculpins. FOOD OP LAKE TROUT 31 TABLE 8 Comparisons of Lake Tahoe Food Habit Studies for Lake Trout Present study 1962 64 Corlett and Wood (1958) 1954-58 Miller (1951) 1948-49 Size (inches fl) 15 to 33 14 to 3G 9 to 32 Frequency (%) Weight (%) Frequency (%) Frequency (%) Volume1 (%) 1 ish (total).. 71.4 35.7 13.5 10.8 1.9 0.2 2.4 3.3 3 . 3 7.:, LI. 3 1.1 L'S S 0.1 0.2 13.7 L5 5 . 3 0.7 0.0 89.1 10.3 36.1 9 . 3 0.8 0.0 1.1 14.2 4.3 11.8 0.8 0.5 0.0 0.0 0.0 9.7 0.0 0.0 0.0 0.0 89.9 45.5 4.7 3.9 14.9 1.2 2.7 L.6 3.1 46.3 0.8 5.9 1.2 0.8 SI) S 50 2 14.0 23.22 1.9 0.7 1 A 19. 6 2.8 18.9 2.1 95 . 7 Piute sculpin .. Tahoe sucker,. 23.9 33. GAME ;ilsn 1).' involved, h is also possible, however, thai annual variations in pre} abundance and availability were responsible. Need for Additional Forage Supply The literature suggests thai lake trout are opportunistic feeders, with a strong predilection \'<>v relatively large prey organisms. In Lake Superior, young-of-the-year '1.1 to 3.7 inches tl) and age I and II 6 to 8.9 inches tl lake trout subsisted almosl entirely on Mysis icta Eschmeyer, 1956 . For both groups, fish occurred in !•'* of the stomachs and contributed aboul l-'< by weight. A 1.5-inch lake troul contained fish larvae. Numerous other studies describe the heavy utilization by juvenile lake trout of relatively large invertebrates, such as Mysis and Pontoporeia, and of small fish as well (e.g., Larkin, 1948; Cuerrier and Schultz, 1957; \Whster. Bentley, and Galligan, 1959; Rawson, 1961; Hacker. 1962; Dryer, Erkkila, and Tetzloff, 11)65). Several authors have commented on tin* significance of such a diet. In one Wisconsin lake, in a year when .1/. relicta was especially abundant, survival of young stocked lake trout increased threefold Threinen, 1962 . Investigations at Waterton Lakes in Canada led Cuerrier and Schultz (1957) to state. ''The availability of small fish for young lake trout seems to be a \ity important factor in the suc- cessful development of the population". Results at another Canadian water, Lake Minnewanka, indicated that a scarcity of forage fish for lake trout under 15 inches was responsible for poor growth and sur- vival of the population (Cuerrier. 1954). McCaig and Mullan (I960) noted a marked increase in lake trout growth rates subsequent to establishment of an abundant population of the American smelt (Osmerus mordax) in a Massachusetts reservoir. Perhaps the best testimony of the impact of food habits on lake trout biology came from a long-term study of a series of Canadian lakes in Algonquin Park (Martin. lf)66'. In lakes where lake trout depended heavily on plankton for summer food, they grew more slowly, did not attain as great a size or age. and matured at a smaller size and younger age in comparison with lake trout in lakes where fish are an abundant summer forage. Annual yield in numbers was higher in planktonivorous than piscivorous populations, but yield in pounds was comparable. We interpreted the Lake Tahoe lake trout population, at least that segment under 15 inches, as more planktonivorous than pis- civorous. During the summer months, most Lake Tahoe lake trout are found in the hypolimnion close to the bottom, whereas most of the potential forage fishes are found in the littoral portion of the epilimnion (Lake Tahoe Fisheries Study, unpubl. data). A number of other workers have described similar distribution patterns (e.g., Martin, 1952; Cuer- rier, 1954). However, at Lake Tahoe considerable overlap exists, since in summer a few lake trout are taken in shallow water. Also, sculpins are abundant at 200 ft and common at 400 ft. The summer distribution data, the predominance of plankton in the diet of fish under 15 inches, and the relatively slow growth rate of Lake Tahoe lake trout (Hanson and Cordon.'. 1967) indicated a need to augment the summer supply of forage organisms in the deep, cold waters occupied by the lake trout. This led to the introduction of the FOOD OF LAKE TROUT 33 opossum shrimp, Mysis relicta, and the Bonneville ciseo, Prosopium gemmiferum (Frantz and Cordone, 1965; Linn and Frantz, 1965). The shrini]) is now established in Lake Tahoe, but its utilization by lake trout has not yet been measured. The status of the cisco is unknown. CONCLUSIONS The diet of lake trout in Lake Tahoe shows several obvious patterns that vary with size of fish and time of year. As trout increase in length they change from an invertebrate to a fish diet. Cladocerans dominate the intake of lake trout under 5.0 inches, and remain significant until trout attain a length of about 15 inches. Other invertebrates, such as immature tendipedids and amphipods, tend to be fairly important in the did of small trout but also decline substantially in importance when the fish reach a length of aboul 15 inches. The crayfish is the one exception to this trend. It is significant in the diet of lake troul under 15 inches and is of moderate importance in the diet of larger fish. Pish are not found in the stomachs of lake troul under 5.0 inches. They become a progressively significant component in the diet of larger trout. Fish between 5.0 and 9.9 inches consume Piute sculpins only, and these remain the most prevalent fish in lake troul stomachs until the trout attain a length of aboul 20 inches. After this, more Tahoe suckers than sculpins are eaten and. because they are much larger, suckers make up an even greater portion of the total weighl consumed. A wider variety of fishes is taken by lake trout over 15 inches, with tui chubs and mountain whitefish assuming prominent roles also. Lake trout \\-c<\ more avidly on fish during the spring months than during any other time of year. Nb1 onl^ are there fewer empty stom- achs in spring, but the actual weight consumed is generally higher at this time of the year. The fewest fish in lake trout stomachs occur in summer. The percentage contribution of sculpins by both frequency and weight is highest during spring for all sizes of lake trout. Because of the dominance of sculpins in the diet of lake trout, the values for all fish combined generally show the same spring peak. However, other species of tishes do not follow the same pattern as the seulpin. Moun- tain whitefish .ire much more prevalent in lake trout stomachs in autumn and winter. Since whitefish spawn in November and December, this may be a function of greater availability, related to their pre- and post-spawning behavior. Suckers and chubs occur most frequently in summer and autumn, kokanee salmon in winter, and lake trout and redsides in spring and winter. Definite trends are observed for the major invertebrates in the lake trout diet. Cladocerans are most common in stomachs of 10- to 20-inch fish in winter, followed by summer, autumn. and finally spring. Crayfish contribute most in the summer to lake trout over 15 inches. ACKNOWLEDGMENTS We wish to express our appreciation to "Rufus W. Kiser of Centralia College. "Washington, for identifying the species of Cladocera and Co- pepoda in stomach samples, and to John D. HopTh'rk and Douglas H. 3 \ I \I.IKuK\i \ PISH AND GAME Evans, who identified fish species Prom vertebra material in the 1962 collection. They ;ilsn prepared keys and stained skeletons wliieli we used to identify vertebrae from the 1963 and 1964 collections. Other indi- viduals who contributed to this study were Phillip II. Baker, Harold K. Chadwick, Ray P. Corlett, Sterling I'. Davis, Thomas J. Trelease, \V. Donald Weidlein, and many conservation aides from both states. REFERENCES Cordone, Almo J., and Ted C. Frantz. 1966. The Lake Tahoe sport fishery. Calif. Fish and Game, 52 I 1 i : 240-1274. . 1968. An evaluation of trout planting in Lake Tahoe. Calif. Fish and Game, 54 (2) : 68 89. Corlett, Ray, and Norman Wood. 1958. Fisheries management report, July 1. 1954 to June 30, L958, Tahoe and Topaz lakes. Nevada Fish and Game Comm., Dingell- Johnson Job Completion Rept., Project No. FAF-4-K. 4~> p. Cuerrier, Jean-Paul. 1954. The history of Fake Minnewanka with reference to the reaction of lake trout to artificial changes in environment. Canadian Fish Cult., (15) : 1 9. Cuerrier, J.-P., and F. H. Schultz. 1957. Studies of lake trout and common whitefish in Waterton Lakes, Waterton Lakes National Park. Alberta. Canadian Wild! Serv., Wildl. Mangt. Bull., Ser. 3, (">) : 1-41. Dryer. William R.. Leo F. Erkkila. and Clifford L. Tetzloff. 1965. Food of lake trout in Lake Superior. Trans. Amer. Fish. See.. !»4 (2) : 160-176. Eschmeyer, Paul II. 1956. The early life history of the lake trout in Lake Superior. Mich. Dept. Cons., Inst. Fish. Res.. Misc. Publ., (10) : 31 p. Frantz, Ted C, and Almo J. Cordone. 1965. Introduction of the Bonneville cisco (Prosopium gemmiferum Snyder) into Lake Tahoe. California and Nevada. Calif. Fish and Game, 53 (4) : 270-275. — . 1066. A preliminary checklist of invertebrates collected from Lake Tahoe, 1061-1004. Biol. Soc. Nev., Occ. Pap.. (8) : 1-12. Hacker, Vernon A. 1062. A summarization of life history information of the lake trout. Salvelinus namaycush, obtained in gill netting, finclipping and tagging studies at Green Lake. Wisconsin — 1956-1961. Wise. Cons. Dept., Fish Mangt. Div.. Fast Central Area, Investigational Memorandum. (3) : 24 p. (Mimeo.). Hanson, Jack A., and Almo J. Cordone. 1967. Age and growth of lake trout, Salve- linus namaycush (Walbaum), in Lake Tahoe. Calif. Fish and Game, 53 (2) : 68-87. Juday. Chancev. 1007. Notes on Lake Tahoe. its trout and trout-fishing. Bull. U.S. Bur. Fish.. 26 : 133-146. Kemmerer. George. J. F. Rovard. and W. R. Boorman. 1023. Northwestern lakes of the United States: biological and chemical studies with reference to possibilities in production of fish. Bull. U.S. Bur. Fish., 39 : 51-140. Larkin, P. A. 1048. Pontopon-in and My sis in Athabaska, Great Bear, and Great Slave lakes. Bull. Fish Res. Bd. Canada. ( 77 i : 33 p. Linn, Jack D., and Ted C. Frantz. 1065. Introduction of the opposum shrimp {Mysis relicta Liven) into California and Nevada. Calif. Fish and Game .~>1 ( 1 1 : 48-51 . Martin. Nigel V. 1052. A study of the lake trout. Salvelinus namaycush, in two Algonquin Park, Ontario, lakes. Trans. Amer. Fish. Soc, 81 (1951) : 111-137. — . 1966. The significance of food habits in the biology, exploitation, and man- agement of Algonquin Park, Ontario, bike trout. Trans. Amer. Fish. Soc, 95 (4) : 415^22. McCaig, Robert S., and James W. Mullan. 1060. Growth of eight species of fishes in Quabbin Reservoir. Massachusetts, in relation to age of reservoir and intro- duction of smelt. Trans. Amer. Fish. Soc. 89 (1) : 27-31. McGauhey, P. II.. Rolf Eliassen, Gerard Rohlich. Harvey F. Ludwig, and Frman A. Pearson. 1963. Comprehensive study on protection of water resources of Lake Tahoe Basin through controlled waste disposal. Prepared for Lake Tahoe Area Council, Engineering-Science, Inc. l.">7 p. Miller, Richard Gordon. 1951. The natural history of Lake Tahoe fishes. Stanford Univ., Ph.D. Dissertation. 160 p. FOOD OF LAKE TROUT 3o Miller, Robert II., and J. R. Alcorn. 1945. The introduced fishes of Nevada with a history of their introduction. Trans Amer. Fish. Soc, 73 : 173-193. Rawson, D. S. 1961. The lake trout of Lac la Rouge, Saskatchewan. Jour. Fish. Res. Bd. ("ana. la. L8 (3) : 423-462. Threinen, ('. W. 1962. What's new in fish management. Wisconsin Cons. Bull., 27 (2) : 14. Webster, Dwight A.. William G. Bentley, and James P. Galligan. 1959. Management of the lake trout fishery of Cayuga Lake, New York, with special reference to the role of hatchery fish. Cornell Univ., Agric. Expt. Sta., Memoir 357. S3 p. Weidlein, W. Donald. AJmo J. Cordone, and Ted C. Frantz. 1965. Trout catch and angler use at Lake Talioe in 1!)C,l>. Calif. Fish and Game, 51 i :; i : 187-201. Vali) I ■ and Oatiu . 56i 1 I : 36 18. 1970. FOOD HABITS OF THE WESTERN GRAY SQUIRREL1 WALTER STIENECKER and BRUCE M. BROWNING Wildlife Management Branch California Department of Fish and Game Fungi were the staple food item of 310 western gray squirrels (Sciurus griseus) collected in Trinity, Tehama, and Monterey Counties, California. Hypogeous (subter.aneanj fungi were the most important, wiih the orders Gasteromycetes and Tubercles occurring in the diet every month of the year. In Trinity and Tehama Counties, pine nuts and acorns also were important i'ems, eaten rrtain.'y in the summer and fa GAME peratures range from below freezing to over 100 K. with 80 F the more common summer maximum. There were five collecting areas in the county. Sampling represented a wide variety of habitats and choice of food. Elevations ranged from 1,800 to 2,800 ft. The habital ranged from canyon bottoms to ridge tops. The vegetation varied from thick conifer forests to oak stands tn more open woodland-grass areas. Tehama Collection Area The part of the Tehama Winter Deer Range in which the squirrels were collected lies in the western Sierra foothills in Tehama County, at elevations from approximately >00 to 3..">00 ft. The area is of vol- canic origin, having been created by a series of lava mud flows from activity in the Mt. Lassen region to the northeast. AYatercourses have cut steep-sided canyons, with prominent rim rocks and lava outcrop- pings, through the once continuous volcanic breccia. The squirrels were collected in the upper margin of the winter deer range, where thickets of California black oak (Q. Jcelloggii) and Brewer oak (O. breweri) occur, and stands of yellow pine grow on the ridges. Western chokecherry (Primus demissa), creek dogwood (Cornus californica . willow, alder (Alnus sp.), and California wild grape ' Vitis californica) grow along the watercourses. The climate is characteristic of much of the central Sierra foothills region of California. Generally, winter temperatures are mild and summer temperatures high. Normally the winters are rainy, while the summers are virtually rainless. Snow occurs occasionally at the lower elevations but usually melts off rapidly, while at the higher elevations it may remain longer. The rainy season is sometimes accompanied by fo<_r. which can last for a considerable time. Monterey Collection Area The study area is in southern Monterey County, in the Santa Lucia Range, a unit of the Coast Ranges. The area is almost 6 square miles in extent and is situated about 3 miles from the coast, in Los Padres National Forest. Elevations range from 1,600 to 2,800 ft on Plaskett Ridge and up to 3.01)0 ft on Prewitt Ridge. The area consists of approximately 80% forest and 20% grass and chaparral vegetation types. Conifers consist of yellow pine, Coulter pine (Pinus coulteri), and coast redwood. Broadleaf trees include inte- rior live oak (Quercus wislizenii) on the higher and drier sites and canyon live oak (Q. chrysoU pis) and tanbark oak (Lithocarpus densi- flora) in draws and canyon bottoms. California bay and madrone (Ar- butus mt nzit sii I are scattered throughout the area. The remaining trees consist of broadleaf maple, red alder (Alnus onrjona . valley oak (Q. lobata), and coast live oak (Q. agrifolia). Two species of wild lilac (Ceanothus spp.), coffeeberry (Bhamnus californica), silk tassel (Garrya fremontii), chami.se (Adenostoma fasciculatum) , poison oak (Rhus diver siloba ) , and manzanita (Arctosiaphylos sp.) are the com- mon shrubs. Temperatures are tempered by summer fogs. Precipitation varies from about 16 to 30 inches per year, with approximately 80% of GRAY SQUIRREL FOOD HABITS 39 the rain (and occasional snow at the higher elevations) falling from December to March. METHODS In the major study. 310 western gray squirrels were collected by shooting over a 5-year period, from June 1!'<;3 to December 1968. Counties represented and animals collected in cadi were Trinity, 112; Tehama, 117; and Monterey, 81. A supplemental collection of 58 squirrels was made in four central Sierra counties and another 31 were taken in Humboldt ( 'ounty. Part of the contents of cadi Stomach was washed iii a fine sieve, to ease identification of individual items. The remainder was used to make gross precentage estimates. .Most items were identified with a dissecting microscope with H'x oculars and 0.7x to 3x objectives. Fungus spores and cell structures of acorns and pine and hay nuts were identified with a compound microscope with lOx oculars and lOx and 4.'!x objectives. Spore and peridium characters were used to identify differenl fungi. Nut and acorn fragments were identified by cell structure, texture, starch reaction to iodine, and the presence of shell and pericarp fragments. The quantity i'\' each food item was determined by visual estimate. The volumes were converted to percentages, which were then summar- ized by the aggregate percentage method .Martin. Gensch, and Brown, 1946). The frequency of occurrence of each item was tallied. RESULTS Hypogeous fungi, pine nuts, acorns, fruit of the California hay. and green leafage (mostly forbs were the major foods eaten. These five foods supplied 96$ of the did in the three main study areas (Tables 1, 2, 3). Supplemental data from the central Sierra counties (El Dorado. Amador, Calaveras, and Nevada) and Humboldt ('ounty re- vealed DO other major food items. Fungi In the three major study areas hypogeous fungi were the staple food, utilized throughout the year (Tables 1. 2, '■'> . Peak utilization oeeurred in June in Trinity County (86ft > and Tehama County (82$ I, and in May in Monterey County (74' < . Seasonal consumption of fungi varied least in Trinity County (56 to Z > ua - 2 = i: = = o ~ ■-. '.- — ■ to r~- 1^ a — --C -.r ic t - • - — -x EC < 3 a- 1/1 >s a k O ") « § ^ S o «* 0 U ^ £ X £ -.So i- I. « t- o II- 0 in Pi — =3 I - > cn rc ~ — 6 0 o — L- U- — 5S > — ~ r- I- CC CC — ii3 x eo -— ~r • - - > *0 — CC — ' ' - = ~ ~ 00 & . * — » fct 3 fe 3 # ? w *• — '2 «£ 'S " c S - — ■ > O F< 0 nTl f^ £ " g"- — — &— i J3 ■£ 5 = . — ■ t£ 5 Sj** s- ■.■z-^,-?. C~~ l^z-B-s.-- itiE r ^ c GRAY SQUIRREL FOOD HABITS 41 3 a- >s a k o X in -O CN e — c n 0- UJ u <* •o CO 2 0 o < F r~ 1— N 0 X «. - o 0- o z ■o o o fa w--cor~CN]co~-coco — — r- — — < 1 — I t-i > oc _. — o a-. t~- 1- to -r -r cm — £ £ i^^i '/ ci - -r cr o ~ o co ceo | U3 CM — ^- cj CO c^ fa 1" - 65 > r- o ^Z fa. t C iC CI > -Cll- ^ n r- o re — ci - — ■ -faj ^ -r re WN NHrt re o 5 - QC 00 CO CM C"l HMrH ■-« ►> 18.5 I.' 0 0.5 4.5 0.5 2.5 1.0 tr 0.5 July fa CO CO — CM — CI > CO c -r — ^ £ *moh 1 ! June - - 1 -r »0 CM CM ~H — 6? > — UO CC CO * • - - u. — — — — — rH CM »-H ■-- > N (N O lO iC ^- t-l *- ICC1CI-X o I- (14) April fa ^« CO CO CO T-4 CQ — co — ~ . -r ^- _^ £ tj :c :r o — — — ^- C3 fa t- — CO CO »0 ~- »C3 — ' — — > IOC400C X re — «- £ £ — re i.O CO C: C O) — Ol Ol IO CJ "--fa fa — :c — CM — ~- > — — C: — £ O ocoNm — CO — CO -^ i-a fa CO CM ~ CM — — 6? > = = O O ^ ^ oi -r cm Fungi (hypogeous) -_- . -. Pine nuts (Pinus spp.j Acorns (Quercus SppJ (irccn vegetation ... . Unidentified nut fragments Hark, woody fragments Unidentified fruit fragments Fungi (epigeous) California bay fruit ( Umbellu- laria c ilifornica 1 Unidentilied matter Needle fragments | Pinus sppj. - Fescue seeds (FestUCd spp. i Oat. seeds (.limn spp.j Squaw carpet dry leafage (Ce- anothus prostratus) Mistletoe ( Phoradendron villoxum) Club moss (Lycopodineae) Needle fragments (Abies spp.,)_ _ 12 l \UKnk\i \ PISH AND GAME *» ■*» ■*» *- *- . - — — ' — CI - Cl iC — Cl — ~ — CM cc 2 I CO CO -H -i^^, 91 - L '3 o- >s o 6 £ n o < > 3 I. 0 u I" —o 5^ CM O O CM t- CO ^ :o :: cj > — Ci CO Ci :c Ci — I' 103 Cl l-H eo 1— < -r cm co -h -h o — 3 o o — C3 — > — te cj ci « — ci -r t-C — L.C; t_ — se «- «- 5 S ~ 8 X •a 0 o ~ — *C •-* (M -^: c-l o « — CI = = o "* ' — ' C*J -- ci — — — o o so — - 5 ^ DC OS 2T a ■/- Cl. : £0 -• - ; c ■ - — :. - - = • ■Scei?'^" r 5 - = > = ^5 GRAY SQUIRREL FOOD HABITS 43 Other Basidiomyeetes fungi identified in the stomachs were Gautiera, Hist< rangium, and probably Mi lanogasU r. Another import, mi group of hypogeous fungi used by squirrels be- long to the Class Aseomycetes, Order Tuberales. Members of this class bear spores in asci, or sacs, rather than on basidia. These fungi are also eaten c\-it;it from wliicli the squirrels were collected. Green Vegetation Gray squirrels ate some green vegetation throughout the year. On a yearly basis, vegetation comprised less than 5$ of the food eaten in the three major study areas. Highesl use in Monterey County occurred in January I 1-'!'. . tn Tehama County it was highest in July (11%) and in Trinity County highesl in February (about 8%). Supplemental Data Pifty-eighl gray squirrels were collected from April to December 1968 Prom several areas on the west slope of the central Sierra, in El Dorado. Nevada. Calaveras, and Amador Counties. The three principal food items, hypogeous fungi, pine nuts, and acorns, were the same in order of importance as in the main study areas (Table 4). Hypogeous fungi made up •">()', of the yearly food consumed, pine nuts 19%, and acorns 10%. Animal matter comprised under 4%, green vegetation •'!' < . and California bay less than 2' , . Another collection of 31 specimens was made in Humboldt County during May, June, July, September, and October 1968. Again there are similarities in the food consumption pattern (Table 5). Peak fungus use occurred in June (71$ ) and May (67$ i. However, fungus use dropped to 8$ and 9$ in September and October, respectively. The average fungus use over the 5-month period was 37%. Pine nuts were the most important item in Humboldt County (48%). The high use of pine seeds extended over a longer period of time. There was a marked rise from 1$ in June to 57% in July. 74' f in September, and 85% in October. Acorns comprised about 6$ of the total diet, and 14' r of the food in September. Other Foods Other items eaten by western gray squirrels, but always in small or trace amounts, were pine and fir needles, fragments of oak, Ceanothus and thistle leafage, pine pollen grains, fescue (Festuca spp.) seeds, and club moss fragments (Lycopodineae). Animal foods, consisting of frag- ments of insect adults and larvae, occurred mostly in trace amounts. The latter were probably obtained when the squirrels were eating fungi. Ants (Formicidae) were the insects most frequently eaten. Ingles (1947), conducting a study in a parkdike area of Sacramento Valley, listed the following foods which he had observed gray squirrels eating: Valley oak Querents looata (acorns, catkins) California black oak Quercus kelloggii (acorns) California black walnut Juglans hindsii (nuts) Pecan Garya pecan (nuts) Almond i.mygdalus communis (nuts) Yellow pine Pinus ponderosa (nuts) Jeffrey pine Pinus ponderosa jeffreyi (nuts) Digger pine Pinus sabiniana (nuts) Monterey cypress Cupressus maorocarpa (nuts) Red mulberry Morus rubra (berries) Silver maple Leer saocharinum (samaras) American elm Vlmus americana (samaras) Mistletoe Phoradendron fldvescens < berries) GRAY SQUIRREL FOOD HABITS r> x o O -^-«3^>- ooatweowwHrHOOOC iC — — — ^Q I « 33 1/3 - ci re CO 02 u — -O i - / • .-: - - i i- i - - — " " — ~ """ n ".= ~ «7 o ° 00 I- .. I— - - - , - 1 tt) .s CO < 2 2 > o> o — 5 c o ^ O D i- ■o o > z > ( — £5 a ■D O O o ■D O E >> - fa i ?j — cr -cr cs — c*) — *-~ r i £ =: = j^ — ~ - — r, ^ — ™ *c tr^: ^-^ -s. v . ~~ y_ w i — £ ~ — z = -j--— - — . = * = — X-~ - - - : ~ - ±Z > — ~ - " ~ H - = ? — -- ~ - as^ ;T .B-a "'-5' »£ S£ t — — ~ t£ — — : — - - x ■> C tt. - - *— ' u~ V. OS — h hi ■fc*j .sa-iS s.a'S.t!^ s : — C" I to ~. ~ — ifl rt — * — I i- £ '5 o- x 0 O £ E § : «a- to s ' O1 < > "5 - n E ■*■ 3 0 I in O 0 > -PC* X CC M i-H ^- — 4 — — c O CM fa •-H ~ C^l ~H > — t^ CO C-3 I - b- o CO ~ — — an I— CM - > oeo-f Ek c. . to p, .8.3 . -255P - w TCI — ^— -*J a - a o a >_ o - a m c . Q* c-7- 6 o-3 » « a 2 0. 3 a -»-> , 3 O * ■ S S a e a M- •2 £ J-£ *j ^ Cj *Jc/i > -S^-e ■ = SO O 3 H ®-C S iJ O Si £,J3 X X ' I- u_^ GRAY SQUIRREL FOOD HABITS 47 Miner's lettuce Montia perfoliata (leaves) Common chickweed Stellaria media i flower buds) Aphis, causing leaf roll in Oregon ash bone Fraxinus oregona DEPREDATION The western gray squirrel is known to do damage to nut crops in northern California, especially in orchards planted in cleared areas within the natural habitat. Walnuts (Juglans spp.) seem to be hit the hardest by the squirrels and reports of damage have come from Napa, Sonoma, Tuolumne, Lake. Glenn, Butte, and Trinity Counties. Al- monds (Prunus amygdalus) and filberts (Corylus spp.) are also eaten by the gray squirrel. Cambium fibers were not found in stomachs examined in this study, although there are reports from both southern and northern California that gray squirrels occasionally girdle the top branches of conifer trees. DISCUSSION Utilization of fungi is not restricted to the western gray squirrel. It may he that all sciurids inhabiting western coniferous forests are dependent upon hypogeous fungi. McKeever (1964) reported that .1(1', of the food of 207 Douglas sqnirrels (Ttunittsciurtts douglasi), collected over a year in the Susanville area of Lassen County, consisted of subterranean fungi. Tevis (1952, 1953) has documented fungi as an important food of chipmunks (Eiihiniiiis spp. . golden-mantled ground squirrels (Citellus lateralis), flying squirrels {Glaucomys sabrinus), and Beechey ground squirrels {Spermophilus beecheyi). Kaibab squir- rels (Sciurus kaibabensis) i Hall, 1967 and Abert squirrels (N. aberti) (Keith, 1965) rely heavily upon hypogeous fungi during certain sea- sons of the year. Even though fungi are the staple food during much of the year, little is known about their nutritional value. The literature gives the impression that the food value of terrestrial mushrooms is rather low. With respect to the hypogeous fungi, however. Singer (1961) states, ''The nutritional value of truffles is higher [than of mushrooms]. Their water content is lower than that of mushrooms. They are high in pro- teinic substances, salts, and phosphorus." Although the role of hypo- geous fungi in the diet of the gray squirrel is not well understood, it appears that the common subterranean fungi play an important part in its ecology. Mast probably is the critical gray squirrel food. Pine nuts are eaten extensively during the summer and fall periods, starting when the pine nuts reach the milk stage. Pine seeds are very high in oil and moderately high in carbohydrates, making them a nutritious food which starts the process of laying on body fat in preparation for overwin- tering. During the fall and winter months, acorns provide the squirrels with a good source of carbohydrates to help condition them to survive the rigors of the winter and the breeding season. Another mast producer along the Pacific Coast is the California bay and the squirrels in Monterey County eat much of its fruit. Very little is known about the food value of bay. Iv i \l.ll'(ii;\l \ PISH AND GAME The influence of food on the annual populations of squirrels is rec- ognized. Allen (1943) stressed the close relationship between popula- tions and food supplies. Christensen and Korschgen (1955), studying the annual mast survey data in Missouri, state thai "there is an indi- cation of a direct relationship of the annual squirrel harvest to the abundance of the acorn crop". It is probable that mast crops are a key factor governing California gray squirrel populations as well. ACKNOWLEDGMENTS special t hanks and acknowledgment goto Bert Knowles, Unit Wild- life Manager from Trinity County. He not only made year-round squir- rel collections and supplied valuable field information, but also ini- tiated the request that the study lie made. Appreciation is expressed to other Department of Fish and Game personnel for assistance in collecting samples and field data. They are: Thomas E. Ramsey, Donald S. Pine. Frank L. Fary. Richard B. Wagner, John R. Bouvier, J. D. Foster, and -lames Montgomery. Gene Gerdes set up the squirrel study area in Monterey County and helped to evaluate its habitat. Identification of some of the funpi was made possible by the expert and enthusiastic assistance of Dr. Harry Thiers, mycologist and pro- fessor at San Francisco State College. REFERENCES Allen. I >. L. 1114.°.. Michigan fox squirrel management. Mich. Dept. Conserv., Game Div., Publ. 100. 404 p. Christensen, I>. \\ .. and L. J. Korschgen. 1955. Acorn yields and wildlife usage in Missouri. Trans. 20th No. Amer. Wild!. Conf., 337—357. Fowells, H. A. 1965. Silvics of forest trees of the United States. V. S. Dept. Agric, Agriculture Handbook No. 271. vi + 702 p. Hall. J. G. 1007. White tails and yellow pines. Xatl. Parks Mag., 44 (235): 9-11. Iimlcs. L. J. 1947. Ecology and life history of the California gray squirrel. Calif. Fish and Game, :::'. (3) : 139 158. Keith, J. O. 1965. The Abert squirrel and its dependence on ponderosa pine. Ecology, 10 . 1 and 2 i ■ 150-103. Martin, A. C. R. II. Gensch, and 0. P. Brown. 1946. Alternative methods in upland gamebird food analysis. Jour. Wildl. Mangt., 10 ( 1 » : 8-12. McKeever, S. I!i04. Food habits of the pine squirrel in northeastern California. Jour. Wildl. Mangt., 28 (2) : 402-403. Singer, R. 1961. Mushrooms and truffles. Interscience Publishers. New York. 272 p. Smith, A., and S. Zeller. 1966. A preliminary account of the North American species of Rhizopogon. Memoirs New York Botanical Garden, 14 12) : 1-17S. Tevis, L., Jr. 1952. Autumn foods of chipmunks and golden-mantled ground squir- rels in the northern Sierra Nevada. Jour. Mammal., 33 (2) : 198-205. — . 1953. Stomach contents of chipmunks and mantled squirrels in northeastern California. Jour. .Mammal.. :!4 I 3 I : 310-324. Calif. Fish and Game, 56(1) : 49-59. 1970. A DESCRIPTION OF THE NORTHERN ANCHOVY LIVE BAIT FISHERY, AND THE AGE AND LENGTH COMPOSITION OF THE CATCH DURING THE SEASONS 1957-58 THROUGH 1 964-65 1 RICHARD WOOD 2 and ALEC R. STRACHAN Marine Resources Region California Department of Fish and Game California's live bait fishery began in 1910, when Japanese albacore fishermen used small forage fish to increase their catch. The fishery is now a rather complicated industry exploiting several different tech- niques to catch, transport, and hoid small marine fish alive until they are sold to sport or commercial fishermen. Voluntary catch records and sampling are used to determine the size of the landings and age composition of the catch for each port of landing. Throughout all seasons reported, there is little variation in the total poundage of northern anchovies (Engrau/»'s mordax) landed for live bait use. Fish of age group I were dominant in most samples taken, closely followed by age group II. One exceptionally large year class, 1959, was noted in the southern California fishery in conjunction with above average sea-surface temperatures. INTRODUCTION The anchovy live bait industry includes the harvest, maintenance, and sale of small, Live, marine fish to anglers for use as bail and or chum. Live bait fishing was introduced to southern California in 1910 by Japanese albacore fishermen, who used small forage fish in their fishing operations. To catch these forage fish, they employed a blanket net and chummed over the net to attract the bait fish. When the bait school was over the net, the net was raised and the fish captured (Young, 1949; Kadovidi and Gibbs, 1!>.">4 . Boats carrying sportsmen to the offshore fishing grounds began using lampara nets for capturing bait in 1912. This kind of net, a special type of round-haul net. is in use today. As the sport fishing industry grew, the demand for live bait also increased, causing a greater degree of specialization in boats ami nets, and in the methods of locating and distributing the live bait. Shortly after World War II. the demands for live bait became sufficient to support a fleet engaged solely to supply bait. This fishery is important today because the most prized sport fishes usually prefer live bait to any other offering. The live bait fishery is located principally in southern California, with smaller fisheries at Morro Bay, Monterey, and San Francisco (Figure 1). During the 1963-6-4 season, over 20 vessels were engaged in the California fishery. During the 1961—65 season, 13 bait vessels operated in the San Pedro area. 1 Accepted for publication June 1969. - Now with Inland Fisheries, Region 3, San Francisco. (49) .-,.1 i AI.II'ui.'M \ PISH AM) GAME V^CsAN FRANCISCO Of\\,BAY N \ SANTA CRUZ A ^MONTEREY I PT. SUR .MORRO BAY d! PT. ARGUELLO \ _ - __SANTA BARBARA \P0RT HUENEME =^>^-v \^C7 .J^^^-v — p^SANTA MONICA \)SAN PEDRO ^"OvNEWPORT ^ ^X ^ /\oCEANSIDE SCALE 1 1 1 1 | 1 ^fVkSAN DIEGO 1 1 1 1 1 1 0 20 40 60 80 100 \%. MILES FIGURE 1 — California northern anchovy live bait catch areas, 1957-65. The shaded areas indicate locations where the fish were actually caught. The mainstay of the industry is the northern anchovy, which com- prises about 98% of the total live bait sold. Pacific sardine, Sardinops caeruleus, white croaker, Genyonemus lineatus, queenfish, Seriphus politus, Pacific mackerel. Scomber japonic us, jack mackerel. Trachurus sijhiiik trie/is. Pacific herring. Chip/ a pallasii, and squid, Loligo opales- cens, comprise the remaining 2%. In the San Francisco area, Pacific herring ranks second to the northern anchovy in importance. The principal methods of locating bait fish are: (i) flashing light or paper recording fathometer, (ii) observation of birds feeding on the surface of the water, (iiij observation of color of a fish school in the water, (iv) nighttime phosphorescent glow or "fireball", and (v) use of lights on small skiffs or fishing boats to attract fish at night. The "fireball" method is used only at night when luminescense caused by the action of the schooling fish can be seen. Using this method, the fishermen are attracted to the bait fish by a " light.'" In a reverse situation, bait fish may be attracted or brought to the fishermen by a light. In the Los Angeles-Long Beach Harbor area, "light plants" ANCHOVY LIVE BAIT FISHERY 51 consisting of a small skiff with a gasoline-powered electric generator providing electricity to light bulbs ranging from 500 to 1,000 watts are used to attract and hold schools of fish so they can be netted (Young, 1950). After locating a school, an experienced skipper can often determine the species by noting the characteristic "color'' or shadow in the water from the schooling fish below the surface. The amount and size of air bubbles released by the fish also arc a clue to the size of fish and species. A lampara net costs from $1,600 to $6,000, depending on size and type of material. It is usually constructed entirely of nylon; however, some nets have cotton wings. Mesh sizes vary from 6 to v inches in the wings to | inch in the "bag" or "sack", stretch mesh. The ne1 usually has a depth range of 20 to 30 fathoms and a cork-line length of 120 to 240 fathoms. When making a set. a marker buoy I lighted at night) attached to one end of the net is thrown into the water, pulling the net off the moving vessel. When the vessel has circled the school of fish, the crew picks up the marker buoy, both ends of the net are placed on a mechanical net puller, and the net wings are brought aboard and stacked on deck until the first part of the bag appeal's. Then the fisher- men pull the bottom of the net aboard, trapping the fish in a section of the bag which remains in the water. Live bait is now ready for sale or transfer to various holding facilities Turner. 1958). Bait may be transferred from the lampara net to a 200- to 1,000- scoop bait tank aboard a hauler in 4- to 20-lb scoops, or in wet brailers with capacities of :!."> to 40 scoops, since 1959, an average weight of 12.5 lb per scoop has been used by the Department to calculate catch ton- nages. Bait also may be transferred directly from the lampara net to a carrier vessel by "swimming" it through an opening in the boat's side. With this method, all but a few inches of water is removed from the carrier's bait tank by discharging it into ballast tanks. The cork line on the bait net is pushed down and a sideboard on the carrier is pulled up. This manipulation causes both water and fish to flow quickly or "swim" into the carrier's bait tanks. A bait operator in San Diego is the only one using this specialized "swimming" method. Bait is transferred from either the hauler's or the carrier's bait tank to sport fishing boats, private boats, piers, commercial fishing boats, other bait carriers, or live bait receivers. Transfers are usually made with a hand scoop ; however, a few bait boats use a wooden trough to sluice the bait into receivers. This sluicing process is called "rolling" bait. A erowder is used to direct the fish into the flume. The receiver is a submerged box made of wooden slats or nylon net strung on a suitable frame. The top is covered with a screen to keep sea gulls and seals from stealing the bait. c AGE AND LENGTH COMPOSITION This report on the age and length composition of the northern an- chovy in the live bait fishery off the coast of California for the 1957-58 through 1964—65 seasons is a continuation of data published on the commercial catch for the 1952-53 and 1953-54 seasons (Miller et al., 1955) ; and for the commercial and live bait catch for the 1954—55 52 i ILIF0RN1 \ PISE AND Q \ VIE through 1956 57 seasons (Miller and Wolf, 1958). The data are pre- sented as seasonal summaries for each of nine ports where catches were sampled. The methods of sampling and age determination are essentially those described by Miller and Wolf. There is no law requiring thai fish sold as "live bait" be reported to the Department and fishermen report their catches voluntarily. Ap- proximately 17)', of the live bait operators cooperate by submitting monthly logs with a daily record of the area fished, number of hauls completed, and the number of scoops of bait sold. Some fail to do so through oversight or lack of time, while a few simply refuse to release the requested catch information. Frequently those few do not under- stand why this information is wanted. An explanation of the live bait study and need for this catch information generally (dears up any misunderstanding. The reported seasonal catch varied little in total poundage throughout the period covered by this report. We have used only those port months for which both samples and landing data are available in computing age composition (Table 1). We have not attempted to estimate missing catch information; there- fore, the poundages and numbers of fish reported are minimal. Boat operators who release all unsold bait at the end of the work day report that portion of their catch which they have marketed as "scoops sold". How much of the released bait gets back into the fishery is not known, but at times the amount released is considerable. Live bait operators who store their bait in receivers until it is sold report their landings as "scoops caught". This bait is held alive until picked up by the sport fishermen. Some of the fish used on sport boats "escape" either off the sportsman's hook, when used as chum, or when released from the boat's bait tank at the end of the fishing day. We have ob- served these releases many times and believe that few fish survive. Our estimates of age and length composition of the catch are based on random samples of 50 fish each. The samples were obtained from bait dealers' nets, bait tanks, and shoreside receivers. Each anchovy was measured to the nearest even mm sl. Scale samples were taken from a male and female in each cm group when possible. The smallest and largest cm groups in which anchovies were measured were 72-80 and 142-150 mm, respectively. The age composition equation used to obtain the numbers of fish landed at each port is discussed fully by Messersmith and Hyatt I 1965). With few exceptions, fish of age group I were dominant, closely fol- lowed by age group II. These two groups usually comprised more than 7.V, of the landings (Tables 2 through 9) 3. No fish older than 5 vears was found ; the oldest anchovy ever recorded was 7 vears (Koedel, 1953). An exceptional season occurred in 1950-60, when there was a very large influx of small fish-of-the-year into the southern California bait fishery. At San Pedro, 86.7% of all fish sampled were of age group 0 (Table 6). This 11)59 year class was very strong and provided a very large proportion of the catch in subsequent years. Even in 1964-65, when these fish were 5 years old. they were still being landed at a majority of ports. 3 Raw data for the ape-lenerth composition by season and port are recorded in Marine Resources Operations Reference Xo. 69-3. ANCHOVY LIVE BAIT FISHERY 53 TABLE 1 Summary of Reported Landings and Age Composition Sampling by Port and Season, 1957-58 Through 1964-65 Season Morro Bay 1957-58— 1958-59- 1959-60—. I960 63 1963 64-.-. 1964-65- Santa Barbara 1957-58— 1958-59..-. 1959 60 1960 lil 1961-64.... 1964-65 Port Hueneme 1957-58 1958 59 1959 til 1961 62 1962 63 1963 til 1964 65.-.. Santa Monica 1957 58 1958-59.. 1959 tin 1960-61— 19(11-62... 1962-63— 1963-64— 1964-65— San Pedro 1957 58 1958-59- 1959 tit) 1960-61 1961-62 1962-63-— 1963 64... 1964-65— Newport Beach 1957-58. 1958 59 1959-61- 1961-62. 1962-63. 1963-64. 1964-65. Oceanside 1957-58— 1958-64— 1964-65— San Diego 1957-58.-. 1 958-59. _ . 1959-60- __ 1960-61— 1961-63.-- 1963-64.-. 1964-65.-- Months I. L S L s s I. I. I. s L S S Reported landings sampled (1,0 122 6 84.9 31 I B 17.5 147.8 122.0 81.5 79 9 37 '' 25.0 134.0 212 5 578 5 197 8 :,n 6 7HJ. 7 881.5 394.0 a 672 . 1 636.4 3,751.7 ■ 5,074 B 2,311.2 1,275.9 5,227.9 2,925.1 765.3 534.6 a 1.655.4 1,100.0 805.0 850.1 221.0 a 109.2 2,497.1 2,291.7 1,673.1 1,361.3 a 414.9 484.6 Reported landings (1,090 lb) 122.6 vi 9 150 6 225.4 1 17.8 129 8 S9.0 162. I a 65.8 136.4 a 22H.5 776.4 600.8 704.4 702.7 881.5 394.0 a 705 ii 845.8 605.8 824.4 1,664.3 4,950.8 5,074.8 2,311.2 1,603 1 5,668 -' 3,271.0 5,390.6 825.4 liss.2 a 1,794, 1 1,419.6 827.2 864.4 318.2 234.4 2,606.0 2,318.6 1,800.4 1,463.6 a 1,121.6 2,183.6 S = Reported landings and sample taken to estimate age and number composition. L = Reported landings, sample not taken. » No reported landings. 54 CALIFORNIA FISH AND CAME TABLE 2 Estimated Anchovy Landings in the Live Bait Fishery by Port and Season, 1957-58 Through 1964-65 * Morro Bay Reported landings duriim sampling months (1,0901b) Age composition during months of sampling (Numbers of fish are given in thousands) Si*™ Number of annuli 0 1 2 3 4 5 Total 1958-59 . 122.6 Year class.. Number Percentage _ 1958 35 0.88 1957 2,451 59.96 1956 1,500 36.69 1955 102 2.49 1954 1953 4,088 100.02 1959-60. 84.9 Year class.. Number., . Percentage . 1959 160 4.90 1958 2,326 71.18 1957 729 22.31 1956 53 1.61 1955 1954 3,268 100.00 1963-64. 314.8 Year class.. Number Percentage . 1963 507 6.61 I'.MiJ 2,2:;:; 29.09 1961 3,220 41.94 1960 1,291 16.81 1959 426 5.55 l:» 7,677 100.00 1964-65 _ 47.5 Year class. . Number Percentage . 1964 1963 123 14.25 1962 394 45.61 1961 261 30.24 1960 74 8.56 1959 12 1.35 864 100.01 * Seasons with no reported landings are omitted. TABLE 3 Estimated Anchovy Landings in the Live Bait Fishery by Port and Season, 1957-58 Through 1964-65 * Santa Barbara Reported landings during sampling months (1,000 lb) Age composition during months of sampling (Numbers of fish are given in thousands) Season Number of annuli 0 1 2 3 4 5 Total 1957-58. 147.8 Year class.. Number Percentage . 1957 106 2.73 1956 1,353 34.78 1955 1,559 40.03 1954 mi:; 20.65 1953 70 1.81 1952 3,891 100.00 1958-59. 122.0 Year class.. Number Percentage . l'.i.is 304 4.74 1957 36.16 1956 3,124 48.65 1955 620 9.66 1954 51 0.79 1953 6,421 100.00 1959-60 . 81.5 Year class _ . Number Percentage . 1959 1958 1,861 57.02 1957 1,318 40.42 1956 84 2.56 1".-..-. 1954 3,263 100.00 1960-61. 79.9 Year class . . Number Percentage . l'.n;n 145 4.72 1959 1,932 62.88 1958 959 31.22 1957 36 1.18 1956 1955 3,072 100.00 1964-65 . 37.9 Year class.. Number Percentage . 1964 1963 255 22.92 1962 654 58.72 1961 199 17.83 1960 1959 6 0.53 1,114 100.00 * Seasons with no reported landings are omitted. ANCHOVY LIVE BAIT FISHERY 55 TABLE 4 Estimated Anchovy Landings in the Live Bait Fishery by Port and Season, 1957-58 Through 1964-65 * Port Hueneme Reported landings during sampling months (1,0001b) Age composition during months of sampling (Numbers of fish are given in thousands) Season Number of annuli 0 1 2 3 4 5 Total 1957-58. 25.0 Year class.. Number Pi i < utage . 1957 11 2.37 1956 162 195.5 219 15 52 1954 81 16.89 1953 8 1 61 1952 181 100.00 1958-59. 134.0 "l ear class.. Number Percentage . 1958 1957 3,481 76 74 1956 B85 19 50 1955 17(1 3.7(1 1954 1953 1,536 100.00 1961 62 212. .". Year class . Number . Percentage 751 11.00 ! 3,030 34 57 1958 341 1.96 1957 60 0.88 1956 6,854 100. 00 1962-63 . 578.5 Year 'lass . Number Percentage 1962 1,026 5.85 1961 10,111 57.68 I960 1,854 .'7 69 19.59 i i ;6 6 is 19.5s 103 2.30 I1 '57 17,530 100.01) 1963-64 . 497.8 5 ear class.. Number Percei 1963 1,503 10 »7 6,343 15 -7 1961 3,845 27.80 I960 1,745 12.62 1959 1958 66 0. 18 13,828 100.00 1964-65. 514.6 *i ear class.. Number Perci i 1964 43 1 6,619 15.02 1962 5,036 34.25 1961 1,941 13.20 I960 5. ; 3.90 1959 99 0.67 11,702 99.99 * Seasons with no reported landings are omitted. TABLE 5 Estimated Anchovy Landings in the Live Bait Fishery by Port and Season, 1957-58 Through 1964-65 ' Santa Monica Reported landings during sampling months (1,0001b) Age composition during months of sampling (.Numbers of fish are given in thousands) Season Number of annuli 0 1 2 3 4 5 Total 1957-58. 702.7 Year class.. Number Percei 1957 101 0.69 1956 4,797 32.76 1955 5,363 36.63 1954 3,521 24.05 1953 692 4.73 1952 165 1.13 14,639 99.99 1958-59 . 881.5 Year class. . Number Percentage . 1958 1,822 7.11 1957 41,007 60.46 1956 21,985 32.42 1955 1954 1953 67,814 99.99 1959-60 _ 394.0 Year class ._ Number Percentage _ 1959 16,179 57.50 1958 10,006 35.56 1957 1 s.'d 6.47 1956 132 0.47 1955 1954 28,137 100.00 1961-62. 672.4 Year class.. Number Percentage _ 1961 3,791 11.84 1960 13,849 43.25 19.59 12,574 39.26 1958 1,585 4.95 1957 221 0.69 1956 32,020 99.99 1962-63 . 663.8 Year class __ Number Percentage . 1962 2,556 9.24 1961 17,253 62.38 1960 6,903 24.96 1959 741 2.68 1958 205 0.74 1957 27,658 100.00 1963-64 . 605.8 Year class . . Number Percentage . 196:: 8,847 36.51 1962 pi. pis 41.72 1961 4,332 17.89 1960 824 3.40 1959 119 0.49 1958 24.230 100.01 1964-65 . 636.4 Year class.. Number Percentage . 1964 5,134 14.52 1963 22,491 63.61 1962 7,733 21.87 1961 1960 1959 35,358 100.00 * Seasons with no reported landings are omitted. 56 C \I.IIM|;\|.\ PISH AMI GAME TABLE 6 Estimated Anchovy Landings in the Live Bait Fishery by Port and Season, 1957-58 Through 1964-65 * San Pedro lain! during sam] mmr [,000 omposition during months of sampling i Numbers of fish are given in thousand*; Nun i ■ of annuli 0 1 2 3 4 5 Total 1957-5S 51.7 Year class.. Number Perc ■! 1957 2,401 1.92 1956 ; g ■ .. 19.55 58,439 16.73 1954 11,905 9.52 1953 1,838 1.47 1952 0.37 125,042 99.99 1958-59 . 1,950. 8 Year class. - Numl Percentage . 1958 2 75 10.68 1957 164,149 59.68 1956 73,548 26.74 55 7,096 2.58 lliol 881 0.32 1".',.; 27.5,049 100.00 1959-60. 5,074.8 Year class.. Number Percentage . 1959 314,242 86.70 1958 28,782 : 94 1957 19,103 5.27 L956 362 0.10 1955 1954 362,489 100.01 1960-61 . 2,311.2 Year class .. Number Percentage . 1960 27,677 23.95 1959 42,146 36.47 1958 39,638 34.30 1957 6,102 5.28 1956 1955 115,563 100.00 1961-62. 4,275.9 Year class.. Number Percentage . r."-,i 17,916 8.38 1960 102,7117 18.04 1 ' ■.".'• 73,310 34.29 19,113 8.94 748 0.35 105'i 213,794 100.00 1962-63. 5,227. '■ Year class.. Number Percentage . 1962 13,401 7.69 L961 I960 64,233 66,394 36.86 38.10 1959 1958 6,726 3.86 1957 279 0.16 174,262 100.00 1963-64 . 2,925.1 Year class.. Number Percentage . l '<»;:; 5,646 6.37 1962 ;. 07g 54.24 1961 2 - 33.20 1960 - 4.42 1959 1,560 1.76 1958 88,640 99.99 1964-65. 4,739.0 Year class. _ Number Percentage . 1964 58,221 29. 1!) 1963 73,850 37.40 1962 46,412 23.51 1961 15,955 8.08 1960 1,797 0.91 l'..5'i 1,224 0.62 197,4.59 100.01 * Seasons with no reported landings are on, ANCHOVY LIVE BAIT FISHERY 57 TABLE 7 Estimated Anchovy Landings in the Live Bait Fishery Port and Season, 1957-58 Through 1964-65 * Newport by Reported landings during sampling mm (1,0001b) imposition during months of sampling .mbers of fish are given in thousands; Season Number of annuli 0 1 2 3 4 5 Total 765.3 Year class.. Number Percentage . 1957 225 1 . 35 5 41.74 1955 ■ - 1954 27 19.71 1953 4 Vt j 1952 639 100.01 1958-59 . 534.6 Year class.. Number Perce: :■■:<- 15,731 ' - 3 46.44 1955 178 0.60 1 954 1953 - 100.00 1961-62 . 1,655.4 Year class.. Number Perci 1961 12,541 15.91 1960 11.31 1959 1958 -.2.5:; 10. 17 1957 197 0.25 1956 I 0.07 78,827 100.00 1962-63 . 1,100.0 Year 1 1 Nuiiil ■ - 6,612 • l'."il 14,363 1 '.itio 11,884 9 79 i 1957 90 0.23 -- 100.01 1963 64 805 0 Year class.. Numb 1963 - 2 5 1 - • 1961 8,961 2jj (4 l'.Mill 656 ■ > in 22 '1.74 1958 57 1964-65 . 850.1 Number Percei 1964 2.27 - 66.61 ■■J 24.39 • 5.01 1 160 - 1.19 ■ 0.23 40,482 100.00 * Seasons with no reported landings arc omitted. TABLE 8 Estimated Anchovy Landings in the Live Bait Fishery by Port and Season, 1957-58 Through 1964-65 * Oceanside Reported landings during sampling months (1,000 lb) Age composition during months of sampling (Numbers of fish are given in thousands) Season Number of annuli 0 1 2 3 4 5 Total 1957-58. 221.0 Year class.. Number Percentage . 1957 316 4.43 1956 3,074 43.12 1955 . 752 - 1954 823 11.55 1953 164 2.30 1952 7,129 100.00 1964-65. 109.2 Year class. . Number Percentage . 1964 266 7.(17 1963 1,369 36.36 1962 2,016 53.54 1961 i 76 1959 38 1.01 3,765 100.00 * Seasons with no reported landings are omitted. - < \I.I|-m|;\| \ PISH \M» QA ME TABLE 9 Estimated Anchovy Landings in the Live Bait Fishery by Port and Season, 1957-58 Through 1964-65 * San Diego irted landings during sampling mom ns f 1.000 lb) t ion during months of sampling Numbers of fish are given in thousand Season Number of annuli 0 1 2 3 4 5 Total 1957-58. 2,497.1 5 ear c]ass__ Number Percentage . 1957 521 0.94 1956 40,210 72.46 12,575 1954 2,020 3.64 1953 166 0.30 1952 55,492 100.00 1958-59 . 2 291.7 Year class Number Percentage . 195* 20,063 19.26 1957 76,472 73.41 1956 7,646 7.34 1955 1951 1953 104,1*1 100.01 1959-60. 1,673.1 Year class.. Number Percentage . 1959 1958 58,337 73.22 1957 20,811 26.12 1956 526 0.66 1955 1954 79,674 100.00 1960-61 . 1,361.3 Year class. . Number Percentage . 1960 1959 33,910 59.79 1958 21,763 38.37 1957 1,049 1.85 1956 1955 56,722 100.01 1963-64 _ 414.9 Year class. . Number Percentage . 196:; 5,112 30.80 2,022 15.80 1961 5,292 31.89 1960 3,051 18.38 1959 519 3.13 1958 16,596 100.00 1964-65 _ 484.6 Year class.. Number Percentage . 1964 2,948 15.02 19C:; 8,622 43.93 1962 7,144 36.40 1961 912 4.65 1960 1959 19,626 100.00 •Seasons with no reported landings are omitted. Water temperatures undoubtedly had much to do with this heavy proportion of small anchovies. Surface water temperatures recorded at Scripps Institution of Oceanography's pier, and at other California Locations, were above normal. Some of the biological anomalies occurring during this period of warm water were reported by Radovich (1961). It is apparent from fishermen's observations, stomach analyses of offshore fish, and our sample data, that the larger anchovies prefer colder waters, and the younger, smaller fish prefer the warmer inshore waters. Bait fishermen have stated that when the sea surface tempera- ture exceeds 62 F schools of anchovies suitable for live bait become increasingly hard to locate. Those large anchovies which remain in the fishing areas become dispersed and do not school. Radovich (1961) stales that large anchovies were found in the stomachs of tuna caught offshore over dee]) waters in 1959. Our samples indicate that fish caught in the bait nets north of Santa Monica Bay. where the waters are cooler, are consistently larger than those caught to the south. SUMMARY 1. Throughout all seasons reported, there was little variation in the total poundage of anchovies landed for live bait use. 2. Fish of age group I were dominant in most simples taken, closely followed by age group II. 3. An exceptional year class. 1959, occurred in conjunction with higher than normal water temperatures in southern California. ANCHOVY LIVE BAIT FISHERY 59 ACKNOWLEDGMENTS We wish to thank the many people -who helped in the preparation of this paper, particularly the fishermen who have been so generous of their time and equipment, and who allowed us to obtain fish samples and gave us their catch information. There have been many sample collectors, all of whom deserve S] ial thanks. Involved in the prepara- tion of this report wt-v the scale readers: John MacGregor, Makoto Kimura, and Robert Wolf of the U.S. Bureau of Commercial Fisheries, Fishery-Oceanography Center, La Jolla, and from the California De- partment of Fish and Game, Anita E. Daugherty (now retired), Harold Hyatt now with the California Department of Public Health), Doyle E. Gates, and C. E. Blunt, Jr. Gertrude Cut lei-. Kathleen <>*Rear, and June Thompson have been mosl helpful in preparation of the manuscript, and J. I). Messersmith gave much valuable advice on the Layout and initial editing. The editorial assistance of John L. Baxter is gratefully acknowledged. REFERENCES Messersmith, J. I>.. and Harold Hyatt. 1965. Pacific mackerel, the commercial fish- ery, and age composition of the southern < *.-i 1 i t" « ■ 11 1 i .-i catch for the 1961 >'>•_'. 1962- 63 and 1963 ni seasons. Calif. Fish and Game, 53 (3) : 168 L82. Miller, Daniel J., Anita E. Daugherty, Francis E. Felin, and John MacGregor. 1955. Au>' and length composition of the northern anchovy catch off the coast of California in 1952 53 and 1953 54, p. -".7 • '>''>. />< Age determination of the northern anchovy, Engraulis mordax. Calif. Dept. Fish and Game, Fish Bull. 101. Miller, Daniel J., and Robert S. Wolf. 1958. Age and length composition of the northern anchovj catch off the coast of California in 1951 '>'>. L955 ."it;, and 1956 •~7. p. 27-72. /// Age and length composition Pacific coast catches sardines and Pacific mackerel 1955-56 and 1956 57 seasons and the northern anchovy 1054— 55 through 1956 ~>7 seasons. Calif. Dept. Fish and Game, Fish Bull. 106. Radovich, John. 1961. Relationships of some marine organisms of the northeast Pacific to water temperatures particularly during 1957 through 1959. Calif. Dept. Fish and Game, Fish Bull. til'. 62 p. Radovich, John, and Earl I». Gibbs. 1954. The use of a blanket net in sampling fish populations. Calif. Fish and Game, 10 (4) : .*;.">•". 365. Roedel, Phil M. 1953. Common ocean fishes of California, Calif. Dept. of Fish and Came. Fish Bull 91. 184 p. Turner. Charles H. 1958. Five bait — a unique fishery. Calif. Dept. of Fish and Came. Outdoor California, 19 (7) : 5 and 10. Young, Parke H. 1949. Live bait fishery, p. 183 189. In The commercial fish catch of California for the year 1947 with a historical review 1916-1947. Calif. Div. Fish and (lame, Fish Bull. 74. — . 1950. Netting bait and cannery fish with the aid of lights. Calif. Fish and Game, 36 (4) : 3S0-3S1. Calif. Fish and Game, 56l 1 i : 60 64. L970. A FIBROMA IN THE ABDOMINAL CAVITY OF A KING SALMON, ONCORHYNCHUS TSHAWYTSCHA' STANLEY C. KATKANSKY, RONALD W. WARNER Marine Resources Region California Department of Fish and Game and WILLIAM H. SHOLES Anadromous Fisheries Branch California Department of Fish and Game A !. and 4 . Small blood vessels were noted in the neoplasm and blood cells were observed in sonic tissue spaces. The outer covering of The fibroma was composed of densely packed collagenous fibers (Figure 5). Microscopic examination revealed no visible organisms associated with this growth. DISCUSSION Neoplasms are seldom reported in fish and of those seen few reach qualified observers. Fish possessing such growths are generally im- properly cared for and of little value if they do reach qualified per- sonnel. In the case of the specimen under discussion, the gills had been removed and discarded and the viscera partially removed from the body cavity before freezing, so the precise manner in which the fibroma was situated in the abdominal cavity is unknown. Verbal reports given to the authors indicate that the ventral portion of the fish was greatly distended. The loss of a portion of the viscera makes an exact deter- mination of the proportion of the weight of the salmon comprised by the fibroma impossible. The freezing of tissue before fixation for histological examination is not advised, since ice crystals tend to damage the tisssue at the cellular level. However, sufficient detail was evident in this fibroma for diagnosis. Examination of this salmon revealed it to be normal in all respects except for the neoplasm. Microscopic examination of the scales indi- 62 C U.II'iiKM \ FISH \\l> QA ME m* ,,^'f * ■«*»>» ■»"-mU:: -X m FIGURE 2 — Collagenous fibers arranged in straight ribbons. 5 S*- ' ' <£ i 7 5 *i jcf*n&\ , A '•' -V— . it. FIGURE 3 — Collagenous fibers arranged in wavy ribbons. FIBROMA IX KING SALMON 63 '• <**' """N* *» * */. mk i "*Nh _«. £ FIGURE 4 — Collagenous fibers arranged in a whorl. FIGURE 5 — Collagenous capsule surrounding the fibroma. 64 CALIFORNIA FISH AXD GAME cated thai it had spenl a year in the ocean. Since this salmon was of average size for its age, the fibroma had qo1 adversely affected its growth to the time of capture. The causative agenl for this neoplasm is not. known. Sindermanii 1966) ;md van Duijn (1967) have indicated possible viral etiologies for neoplastic growths in fish, hut we were nimble to test this pos- sibility. We consider this neoplasm to have been benign because of its non- invasiveness. It is of interesi to note the similarities of this fibroma to those described by bobbins (1962) in human pathology. ACKNOWLEDGMENTS The authors express their sincere appreciation to E. W. Engberg, skipper of the sport fishing boat Marian, for saving and reporting the specimen discussed here. REFERENCES Nigrelli, Ross F. 1953. Tumors and other atypical cell growths in temperate fresh- water fishes of North America. Trans. Amer. Fish. Soc., 83 : 262-296. Robbing, Stanley L. 1962. Textbook of pathology with clinical application. 2nd ed. W. B. Saunders, Philadelphia. Pennsylvania. 1190 p. Schlumberger, II. «;.. and Paldnin Lucke. 1948. Tumors of fishes, amphibians, and reptiles. Cancer Pes.. 8 (12) : 657—754. Shaw, Barbara P.. and Helen I. Battle. 1957. The gross and microscopic anatomy of the digestive tract of the oyster Crassostrea virginica (Gmelin). Canadian Jour. Zool., 35 (3) : 325-347. Sindermann, Carl J. 1966. Diseases oi marine fish, p. 1—89. In Advances in marine biology, Vol. 1. Academic Press, London and New York. van Duijn, C, Jr. 1967. Diseases of fishes. Charles C. Thomas, Springfield, Illinois. 309 p. NOTES A PUNCH TO FACILITATE THE REMOVAL OF SALMONID OTOLITHS1 There are three pairs of otoliths in the inner ear of teleosts. Of these, the sagittae have been used for age determination in salnionids ' Mc- Murrieli, 1910, 1913; Clutter and Whitesel, 1950; Kim and Koo, 1963; Koski, 1964; Bilton and Jenkinson. 1968; and Kim and Roberson, 1968), as wed as in other fishes (Hickling, 1931; Einarsson, 1951; Fitch, 1951 ; Kohler, 1958; Larsen and Skud, 1960; and Watson, 1965 . The location of the sagittae beneath the eranial cavity makes them difficult to remove. Kim and Roberson (1968 collected otoliths by splitting the heads of sockeye salmon. Oncorhynchus nerka. Koski (1964) found this method tedious and messy, and developed an "oto- lith punch'1 for taking sagittae from sport-caught steelhead trout, Salmo gairdnerii, without mutilating the heads so badly. The punch was used to remove a circular plug from the skull of the fish to expose the cranial cavity. The brain was removed and the sagittae were lifted from the exposed pockets. We found Koski's punch cumbersome, and constructed the improved model described herein. MATERIALS Tlie materials used to construct our unproved punch were two lengths of |-inch (I. I).' steel conduit, i wo lengths of |-inch diameter Plexiglas rod, a 3 x £-inch spring, and a 2^-inch length of i-ineh diameter steel rod. A 2^-inch length of conduit served as a handle, while a 4.1-inch length was used for the barrel. A 3-ineh length of Plexiglas rod was used to till out the contour of the handle, while a 2^-inch length served as a plunger to remove tissue from the barrel. The spring activated the plunger, and the steel rod acted as a trigger. CONSTRUCTION The conduit. Plexiglas. and rod were cut to appropriate lengths. Ends of the shorter length of conduit, both lengths of Plexiglas, and the rod were smoothed. One end of the barrel was notched to tit closely the contour of the handle. Next, the handle was silver-soldered to the barrel. With a drill press, a series of six T3j;-inch holes was bored through the barrel beginning 1-| inches from the open end and pro- gressing toward the handle. At the top of this series, one hole was bored to the side of the last hole. A small round file was used to connect these holes, and the slot between the holes was smoothed with a flat file. The finished slots were hook-shaped, with the openings to the hooks opposed, at the end closest to the handle (Figure 1). To assemble, the plunger was inserted in the barrel so that one end was flush with the terminus of the barrel, then a £-inch hole was bored 1 Supported by funds from the Sport Fishing Institute. Technical paper Xo. 2708, Oregon Agricultural Experiment Station. (6.j) <;<; CALIFORNIA PISH AND GAME handle filler for handle spring barrel- trigger plunger Otolith Punch Ss3 /T\ zn& r 41 front side /cocked for Waking otoliths ) FIGURE 1 — Construction details of the punch used to remove otoliths from steelhead trout and other large salmonids. 1li rough the plunger at the bottom of the slot. The plunger was then removed and the cutting end of the barrel sharpened. Finally, the spring was placed in the barrel, followed by the plunger, which was sufficiently depressed to permit the rod to be centered through the hole. The otolith puneh was now completed. By compressing the spring and rotating the plunger so the rod caught in the hooked ends of the slots, the punch could be cocked. USE OF THE OTOLITH PUNCH Taking otoliths by this technique depended on cutting the core from the appropriate area of the cranium. The scales of salmonids end in a broad "V" shape at the nape (Figure 2). When the core was taken just anterior to the "V," the region of the cranial cavity directly above the sagittae was exposed. The tip of the puneh was allowed just to break through the skull so that a core was withdrawn without forcing XOTES 67 forebrain midbrain otolith enclosed in sacculus hindbrain exposed brain after plug has been removed. Y shaped i ^anteriodorsal K|§^end of scales. FIGURE 2 — Diagram of a salmonid head showing the area from which the circular plug and otoliths were removed. An enlargement of the area exposed by removal of the plug is shown at the top of the figure. the sagittae out of position. The otoliths were then gently removed with forceps. Once the otoliths were removed, the tip of the punch was placed in the hole and the trigger tripped. In this way, the core was replaced and the appearance of the fish was only slightly damaged. "We used this punch to collect otoliths from over 250 steelhead trout and found it to be a convenient and effective tool. 68 C U.H'OKM \ PISH AND GAME REFERENCES Bilton, II. 'I'., and D. W. Jenkinson. I DOS. Comparison of the otolith and scale methods for aging sockeye (Oncorhynchus nerka) and chum [0. keta) salmon. .Ion,-. Fish. Res. Bd. Canada, 25 : L067 1069. Clutter, K. I., and L. B. Whitesel. 1956. Collection and interpretation of sockeye salmon scales. Inter. Pac. Salmon Fish. Comm., Bull. IX. 159 p. Einarsson, Hermann. 1951. Racial analysis of [celandic herring by means of otoliths. Conseil Permanent Inter, pour I'Explor. de la Aim-, Rap. Proces-Verbaux, 128 ili: 55-74. Fitch, John E. 1951. Age composition of the southern California catch of Pacific mackerel 1939 K) tlirou-li I'.i.lu ■ r.l. Calif. Dept. Fish and Game, Fish Bull. 83. 73 p. Hickling, C. F. 1931. The structure of the otolith of the hake. Quart. Jour. Mi croscop. Sri.. 7 1 i4) : 547—561. Kim, Wan S., and Ted S. Y. Koo. 1963. The use of otoliths for age determination in red salmon. Fish. Res. Inst., Univ. Wash., Seattle, Contrib. (147) : 17-19. Kim. AN" .in S.. and Kenneth Kolierson. liMi.S. On the use of otoliths of sockeye salmon for age determination, p. l-l'.t His. /// Robert L. Burgner [ed.]. Further studies of Alaska sockeye salmon. Univ. Wash.. Publ. Fish., New Series, Vol. Ill, Seattle. Kohler, A. C. 1958. The validity of otolith age determinations for haddock (Melano- (niiiii in us aeglefinus L.) from the Lockeport, X. S., area. Jour. Fish. Res. Bd. Canada, 15: 1229-1238. Koski, K V. 1964. The use of otoliths for age determination and stock differentia- tion in steelhead trout, Salmo gairdneri Richardson. Oregon State Univ., Dept. Fish, and Wildlife. 10 p. (typewritten). Larsen. Charles M.. and Bernard E. Skud. 1960. Techniques for studying herring scales and otoliths. Prog. Fish-Cult., 22 (2) : S5-S6. McMurrich, J. Playfair. 1910. The life history of the Pacific salmon. Trans. Cana- dian Inst.. Toronto, 9 (1) : 23-44. — . 1913. The life cycles of the Pacific coast salmon belonging to the genus Oncorhynchus, as revealed by their scale and otolith markings. Roy. Soc. Canada. Ottawa, Proc. and Trans. 1912, ser. 3, vol. 6, sec. 4, Geol. and Biol. Sci., p. 9-28. Watson, John E. 1965. A technique for mounting and storing herring otoliths. Trans. Amer. Fish. Soc. 94 (3) : 267-268. J aim L. McKcrn and Howard F. Horton, Department of Fisheries and Wildlife, Oregon State University. Accepted August 1969. A NOTE ON THE BEHAVIOR OF THE OCTOPOD OCYTHOE TUBERCULATA On February 4, 1967, Avhile diving from the charter vessel Maverick in Emerald Bay, Santa Catalina Island, California, I captured an octopus. With the aid of John E. Fitch (California Department of Fish and Game), I identified it as a male Ocythoc tuberculoid Rafinesque. I first observed the octopus inside the body cavity of a salp, Thctys vagina, which was approximately 6 ft above the bottom in water 30 ft deep. As I approached to investigate, the octopus momentarily left the salp for a maximum distance of about 4 inches before returning to its "hiding place". When I grasped the salp, the octopus abandoned it and swam about 60 ft before I could capture it; at that time it expelled ink which formed a cloud. Close examination showed that the salp was dead, as there was no body pulsation and the diagonal septum was absent. Both the octopus and the salp are now in the possession of S. Stillman Berry of Kedlands, California. Among pelagic octopods of the superfamily Argonautoides 'Berry. 1910), one of the third pair of arms (either right or left) is sexually modified into a hectocotylus. In 0. tub< rculata this is the third right NOTES 69 arm. The hectocotylus has a sperm reservoir near its base and a fila- mentous organ at its end. Until the male Ocythoe is mature the hecto- cotylus is contained in a sack. This sack is hurst by the movements of the hectocotylus and eventually the hectocotylus breaks from the octopus (Lane, 1960). The hectocotylus on my specimen was extended at the time captured (Figure 1). Berry (1955) indicated that he had not seen the hectocotylus of any 0. tuberculata taken from California FIGURE 1 — Male Ocythoe tuberculata with hectocotylus extended. Photograph by Jack Schott. waters, and that if racial differences occur in this worldwide species they would most likely be detected in the elaborate hectocotylus. Since 1955, John E. Fitch (pers. comni.) has found male Ocythoe in sev- eral fish stomachs; however, none had an extended hectocotylus in good condition. Berry (1955) noted that ""no student of the genus has ever possessed material from outside his own area of investigation sufficient to permit direct comparison of comparable series." Therefore, as Berry did, I have included here some measurements made on this Ocythoe (Table 1). TABLE 1 Measurements of Ocythoe tuberculata taken at Santa Cataiina Island Total length 69 mm Length of body (dorsal) 16 mm Tip of body to interocular line 18 mm Tip of body to base of dorsal arms 22.5 mm Maximum width of body 14 mm Width of nuchal commissure 12 mm Width of head at eyes 13 mm Length of funnel 9.5 mm Mouth to tip of right dorsal arm 49 mm Mouth to tip of left dorsal arm 49 mm Mouth to tip of right second arm 25 mm Mouth to tip of left second arm 23 mm 70 CALIFORNIA PISH AND GAME TABLE 1 — Continued Measurements of Ocythoe tuberculoid token at Santa Catalina Island Mouth to tip of hectocotylus arm 51 mm Mouth to tip of lefl third arm 21 mm Mouth to tip of righl ventral arm 54 mm Mouth to tip of lefl ventral arm 54 mm Mantle length (ventral) 15.5 mm .Mam I. • breadth 13.5 mm Diameter of largest sucker of first left arm 1.8 mm Diameter of largest sucker of second left arm 1.5 mm Diameter of largest sucker of third left arm 1.2mm Diameter of largest sucker of fourth left arm 1.8 mm Diameter of largest sucker of hectocotylus 2.1mm I found only one publication that reported octopods in salps. Jatta (1896) recorded the occurrence of a male Ocythoe tuberculata in Salpa tilesii and noted that Schmidtlein had in 18s0 (no reference given; recorded finding a male Argonaut a argo in a salp. REFERENCES Berry, S. Stillman. 1910. A review of the cephalopods of western North America. Bull. U.S. Bur. Fish., 30 : 207-330. — . 1955. On recent Californian occurrences of the rare octopod Ocythoe. Calif. Fish and Game, 41 (2) : 177-181. Jatta, Giuseppe. 1896. Fauna and flora des Golfes von Neapel und der Angren- zenden Meeres-Abschnitte. Herausgegeben von der Zoologischen Station Zu Neapel. 23. Monographic: I Cefalopodi, 268 + 31 p. Lane, Frank W. 1960. Kingdom of the octopus. Sheridan House, New York. 300 p. James E. Hardwick, Marine Resources Region, California Department of Fish and Game. Accepted June 1969. ESTABLISHMENT OF TILAPIA MOSSAMBICA PETERS IN BARD VALLEY, IMPERIAL COUNTY, CALIFORNIA On July 2, 1968, Franklin Hoover and Marschall Stevens, California Department of Fish and Game, verified the presence of tilapia in two irrigation drains, the Araz Drain and the Reservation Main Drain, near Bard, Imperial County. The only other known free-living tilapia in California exist in a small ditch near the Hot Mineral Spa, Imperial County, approximately 75 miles northwest of Bard (Sit. Amant, 1966 j. Melvin Sheldon, Imperial Irrigation District, first informed us of the presence of tilapia in Bard Valley on June 28, 1968. Ethelwynn Trewavas, British Museum (Natural History; Zoological Department, provided positive identification of the tilapia as T. mossambica. Carl L. Hubbs, Scripps Institution of Oceanography, gave valuable assistance in the identification. Tilapia were collected from the Araz Drain in July 1968, and from the Reservation Main Drain in July 1968 and February, May, and June 1969. Tilapia are known to exist, from these collections, in approximately 15 miles of these drains. Water temperatures in most areas of these ditches seldom drop below 60 F (Melvin Sheldon, pers. conmi.). This temperature is within the lower temperature limits of T. mossambica (Kelly, 1957). NOTES 71 The Arizona Game and Fish Department introduced T. mossambica in several drains near Yuma. ■•The Tilapia that were stocked in the Yuma canal system are T. mossambica and have been self-supporting in that area for some six years." A I Essbach, pers. comm., 1968.) We believe the tilapia now found in the Bard Valley originated from the tilapia introduced near Yuma, and are the result of natural migration or unauthorized introductions. Due to the popularity of tilapia as a sport fish, we anticipate its further dispersal in southern California as a result of unauthorized introductions by anglers. REFERENCES Kelly. II. I>. 1957. Preliminary studies on Tilapia mossambica Peters relative to experimental pond culture. Proc. Ann. Conf. Southeastern Assoc. Game and Fish Comm., to : 139 1 19. St. Amain, James A. 1966. Addition of 'l'ili. California Department of Fish and Game. Accepted August 196! >. SCRUB JAY POSSIBLY FEEDING ON ECTOPARASITES OF A BLACK-TAILED DEER A scrub jay (Aphelocoma coerulescens possibly feeding on ecto- parasites of a Columbian black-tailed deer (Odocoileus hemionus co- lumbianus) was observed on Augusl 31, 1965, about 2 miles northeast of Alpine Lake. Marin County, California. Through 7 \ 35 binoculars, we s;iw the jay land on the back of the foraging deer As we moved to within appoximately 60 yards of the deer, a three-point buck, it looked directly towards us and s1 1 motionless. The jay quickly flew to the antlers and perched there a few moments. It then hopped onto the head and. pecking at the skin every few seconds, moved from the head down the back of the deer's neck. After remaining on the deer 2 or •'! minutes, the jay flew a short distance away and disappeared into the brush. The deer appeared undisturbed by the bird's activity; it remained motionless, watching us, for at least 5 min. We believe that the jay was feeding on ectoparasites (ticks or deer keds or both), although we could not see them. Dixon (1944) reported seeing a "California Jay" (scrub jay) presumably picking ticks and deer keds from a mule deer in Sequoia National Forest on March 22, 1944. Local residents told him that this was a common sight. REFERENCE Dixon, J. S. 1944. California jay picks ticks from mule deer. Condor. 46 : 204. — Terry A. Schulz and Paul D. Budwiser, G. ^Y. Hooper Foundation, University Of California Medical Center, San Francisco. Accepted August, 1969. BOOK REVIEWS The Fishes of the British /s.'es and Nor'h-West Europe By Alwyne Wheeler; Michigan State University Press, East Lansing, 1969; xvii + 613 p., pro- fusely illustrated in color and black-and-white. $25. Species accounts take up the bulk of tins volume and are separated into throe natural sections: lampreys and hagfish (12 pages) ; sharks, rays, and ohimaoras (NL> pages) : and bony fishes (474 pages). The texl starts off with an 8-page list of species (396 entries), which I found more useful than the index. This list is arranged systematically by family and includes the authority for each scientific name as well as the date of publication. A 9-page "picture key" follows the introduction, and should prove especially help- ful to the individual with little or no knowledge of fish families and higher groups. Keys to genera and species appear throughout in appropriate sections, and again sketches have been used to illustrate salient features. Typical treatment for a given species includes a listing of its common (in the British Isles) and scientific names, and in a few instances an "authorized" or fisherman's vernacular. Rarely a popular synonym is given for the scientific name, but never more than one. French, Dutch, German, Danish, Norwegian, etc., vernaculars are listed, and details are given for distinguishing the species being discussed. This account is followed by a concise report of available biological data including size, diet, depth distribution, spawning habits and behavior, age and growth, and so on. Distribution is depicted by means of a shaded map of the British Isles and northwest Europe but, of course, many species range well beyond the margins of this standardized map. Almost every species is illustrated with a line drawing and 77 species are in- cluded in the 16 color plates. This volume is indispensable to anyone concerned with the fisheries or fishes of northwest Europe. Since many of the ichthyologists and fishery personnel using this book have only a cursory knowledge of the taxonomy and systematics of the fauna, it is unfortunate that so few synonyms are given for the various scientific names. The price of the book is bound to limit its sale, particularly among students and struggling fishery workers — people who have the greatest need for the information contained in this work. — John E. Fitch. Deep-wat?r Tcleostean Fishes of California By John E. Fitch and Robert J. Lavenberg; University of California Press, Berkeley and Los Angeles, 1968; 155 p., illustrated. $2.25 paper. This book is number 25 in the series of California Natural History Guides, pub- lished by U. C. Press. It covers 71 families of fishes that inhabit the ocean off Cali- fornia, For each family, one "typical" member is illustrated with a coquille-board drawing, and that species is rather thoroughly discussed. The coverage for each illustrated species includes : "distinguishing characters", "natural history notes", "fishery information", a notation of "other family members" and characters for distinguishing them, and the "meaning of [the scientific! name." Much of the in- formation, particularly that concerning life history, is based upon original research by the authors. These notes contain a storehouse of knowledge obtained from the many combined years the authors have devoted to the study of marine fishes. In several instances, more than one member of a family is illustrated. These "additional" drawings show species that are "oddballs" within the family, or, in the case of the gonostomatids, Cyclothone and Danaphos, depict two of the several subgroups found in this large family. In all, there are 74 figures and all were drawn from fresh or preserved specimens, or from photographs when exteremely large and unwieldy fishes were involved. These illustrations are both detailed pnd accurate; hence, they are of tremendous help in identifying deep-sea fishes for those who are not thoroughly familiar with these creatine-. In a brief introductory section, the authors discuss, among other things, such items as "special adaptations of some deep-water fishes", the "history of deep-water ( 72 i REVIEWS 73 ichthyology affecting California", and '"California's fossil record of deep-water fishes." Three appendices contain some very useful information, especially the "checklist of deep-water teleostean fishes from off California." Fisheries workers will for the first time have a complete list of known forms inhabiting the deep waters off our coast. Authorities and publication dates are given for the almost 260 species considered. Finally, there is a glossary and an index. Several minor errors have crept into this edition. On page 42 mid-Chile is listed as 18° S; the date of publication for Scopelogadus mizolepis oispinosus (Gilbert) should be changed from 1890 to 1915. In distinguishing the two genera of threadtail snipe-eels (p. 64), the authors separate Avocettina "in having only one set of pores along the lateral line compared with five in Nemiehthys". Lateral line pores in a row (Avocelliita ) vs lateral line pores of three rows i S'emichthys) seems less con- fusing and is more prevalent in previous literature. The omission of Survey of Pelagic Fishes of the California Current Area (Berry, F. H., and H. C. Perkins, 1966, U.S. Fish and Wildl. Serv., Fish. Bull., 65(3) : 625-682) from the list of "helpful references" is an unfortunate oversight. The use of superlatives in discussing this volume can not be avoided and its publication must be considered a major contribution to the understanding of Cali- fornia marine fishes and deep-water fishes in general. Ichthyologists, marine biolo- gists, librarians, teachers, and students can only look forward with great anticipation to future volumes by Fitch and Lavenberg on other marine fishes of our coast. — Robert N. Lea. The Behavior and Physiology of Pinnipeds Edited by R. J. Harrison, Richard C. Hubbard, Richard S. Peterson, Charles E. Rice, and Ronald J. Schusterman; Appleton-Century-Crofts, New York, 1968; xiv + 411 p., illustrated. $12. This volume is a collection of papers writ ten and edited by five noted experts on pinniped behavior, physiology, and husbandry, with contributions from several other experts from closely related Gelds. The book is divided into four parts ; the first two deal with behavior, one being primarily etiological, the other dealing with experimental behavioral studies of captive animals and trained animals in the wild. The two remaining sections deal with physiology and husbandry. The various parts of the book, each under a separate editor, describe recent and ongoing pinniped research along with a comprehensive review of the literature and past research. One facet of pinniped research receiving considerable attention in recent years involves the ability of various pinnipeds, notably the California sea lion, to utilize active sonar or echolocation in much the same way as do porpoises. Chapters written by Poulter, defending the echolocation theory, and by Schuster- man, negating the echolocation theory, appear in different parts of this book and provide an interesting dichotomy of views. It is especially interesting since the two researchers, both well-known in their fields, have conducted much of their basic research concurrently at Stanford Research Institute's Bio-Sonar Laboratory in Fremont, California. Though much of the book is concerned with research conducted on seals and sea lions found in the eastern Pacific, attention is also given to pinniped species from all over the world. The chapters on general physiology and pinniped nutrition pro- vide information on nearly every species of seals, sea lions, and walruses found throughout the world. The chapter on husbandry is excellent and provides valuable information on feeding, housing, handling, and medical care. It is obvious that no single volume can adequately cover the more than 20 genera of pinnipeds found throughout the world. This publication does, however, bring together into one volume most of the recent information on the physiology and behavior of pinnipeds and provides an excellent source of information for anyone conducting research in this field. — Mel Odemar. From Sea to Shining Sea, A Report on the American Environment — Our Natural Heritage Prepared by the President's Council on Recreation and Natural Beauty; U.S. Government Printing Office, Washington, D.C. 20402, 1968; 304 p., profusely illustrated with black-and- white photographs. $2.50 paper. The stated major objectives of this report are (i) to outline progress in environ- mental improvement programs since the 1965 White House Conference on Natural i I CALIFORNIA FISH AND GAME Bi auty, (ii) t<> present proposals and recommendations which will stimulate federal, state, local, and private action to further enhance the quality of our environment and the beauty of our Nation, and (iii) to present a guide for action by local officials, professional men and women, citizen groups of many kinds, and individuals. The report presents ;i well-balanced although aecessarily somewhal Limited cross ion of the environmental problems which lower the quality of our everyday lives. I'. word and picture, the reader is taken through the country's urban, rural, I wild areas; presented with the actions required and being taken to cope with their problems; and given extensive lists of publications, films, and agencies and organi- :.ii ions which can help. Undoubtedly, Ibis publication will prove useful. To the interested but less initi- ated, it may be an eye opener. To those already well versed in the problems of our environment, it will serve as a reasonably comprehensive compendium. Recognition of the environment is not new. In the early years of the Republic Thomas Jefferson wrote, "Communities should be planned with an eye to the effect made upon the human spirit by being continuously surrounded with a maximum of beauty." A century later President Theodore Roosevelt, and later Presidents Franklin D. Roosevelt, John F. Kennedy, and Lyndon B. Johnson, issued strong statements phasizing the importance of natural beauty and the need to preserve, restore, and enhance the Nation's environmental quality. Will Americans at last respond to these wise admonitions? Perhaps they will when they finally realize that environmental quality is a necessity rather than a luxury. — Leo Shapovalov. Symposium on Salmon and Trout in Streams Edited by T. G. Northcote, Institute of Fisheries, The University of British Columbia, Vancouver, 1969; 388 p., illustrated. $3.00 paper. Sold by Institute of Fisheries Library. The H. R. MacMillan fisheries symposia, held annually at the Institute of Fisheries of The University of British Columbia, merit more attention outside the local area than they seem to get. judging from this report on the 1968 session. It contains 23 contributions on various aspects of trout and salmon biology in streams, including reproduction, egg and alevin ecology, feeding, growth, movement, survival, and pro- duction dynamics. The individual papers are generally excellent. They tend to em- phasize behavioral and ecological phases of salmonid biology. Some of the papers are general; others report on detailed investigations of species as varied as rainbow trout, sockeye salmon. Atlantic salmon, and ayu. Fisheries professionals interested in salmonid biology will find this symposum a valuable addition to their libraries because it draws so much information and so many literature citations together in one place for convenient reference. — Alex Calhoun. Managing Water Quality: Economics, Technology, Institutions By Allen V. Kneese and Blair T. Bower; The Johns Hopkins Press, Baltimore, Maryland, 1968; x + 328 p., illustrated. $8.95. This book represents an up-to-date review of the problems associated with water quality management and pollution control, with emphasis on economic analysis. The first four chapters are devoted to summarization of the basic elements of water quality problems facing this nation. The reader who may be unfamiliar with these elements will profit from the authors' treatment of basic issues, the nature of waste discharges and their effects on receiving waters, the relation of water quality to water uses, and the management of waste loads in relation to waste assimilative capacity of the receiving waters. Having established a base of understanding of the physical problem, the bonk then treats the economic concepts and policies I'm- controlling waste discharges. Here under one cover and directly related to water quality is a summary education in the economics of pollution. It explains the terms and concepts which arc so often used in water management these days but which are frequently confusing to the water quality biologist or manager untrained in economics. Although fairly easily understood, it is by no means a simplified treatment of economic principles. As is the case with most such treatments, this section tends to reduce all facts of the problem to one of minimizing costs and making dollar comparisons. However, unlike many economic oriented treatments of such problems, the authors recognize the difficulty of assessing and properly weighing the values of intangibles and also conclude that the levels of water quality to be achieved in each of the nation's watercourses cannot be directly established on economic ground-. REVIEWS 7.") The authors go on to detail the cases for and problems associated with economic incentives for reducing waste discharges, including effluent charges, incentive pay- ments, henefits to industrial users, effluent standards, tax breaks, sewer charges, etc. It is of interest to note that on the basis of certain limited studies and analyses the authors come to the conclusion that ". . . higher water quality must be justi- fied primarily on aesthetic and recreational grounds, if it is to be justified at all". The studies indicate that provision of high quality water for industry or municipal uses is seldom justified economically. The authors conclude from their analysis that, despite some shortcomings and problems, t lie effluent charges approach is the one must likely to result in efficient and equitable arrangements and thej sin. urge reorienting the nation's policies in this direction. The book discusses several case studies of problem rivers, including the Delaware, the Potomac, and the Ruhr River basin of Germany. Institutional and organiza- tional approaches to water qualitj control in the Ruhr, England, France, and the Delaware River Basin Commission are discussed and compared. Finally, the authors sel forth their recommendations for a regional water quality management agency, including its objectives, organization, criteria to be met, and financing. Although the book's treatment of water quality problems in relation to fish and wildlife is somewhat sketchy and at leasl in one place misleading ("Salinity . . . within limits ordinarily encountered ... is not destructive of fish life, . . ."), it is of value to the fisheries biologist and particularly to the water quality biologist. It conveys a clear picture of economic, organizational, and institutional problems which -.. i. lie,, have a major effect on the control of pollution in relation to fish ami wildlife. — J. C. Fra Oceanographic Atlas of the Pacific Ocean By Richard A. Barkley; University of Hawaii Press, Honolulu, 1968; 20 p. + 156 full-page figs. $30. This atlas summarizes the results of observations made throughout the Pacific ( rcean during a period of over 50 years. Data gathered at over 50,000 stations, representing some 3 million individual observations of temperature, salinity, dissolved oxygen, and depth of sampling, provided the basis for the document. As might be expected, these observations were quite unevenlj distributed in both time and space, but in many areas they provided adequate data to determine conditions during each of the four quarters of the year. Contours of equal depth, salinity, and dis- solved oxygen concentration are indicated on individual charts as continuous lines when adequate data are available, and as dashed lines when data are lacking but continuity reasonably can be inferred. The most significant feature of the procedures for processing observed data for this atlas is the use of an interpolation technique based upon density rather than depth as the independent variable. Values derived from the density relationships seem to reflect conditions in the upper layers of the sea better than values derived from depth relationships. This feature makes the atlas particularly valuable to marine scientists concerned with the upper li.OUU meters of the Pacitic Ocean. While the atlas is a welcome addition to the library of the marine scientist, it is of limited value to the layman — Herbert W. Frey. The Life of the Marsh By William A. Niering; McGraw-Hill Book Co., New York, 1967; 232 p., profusely illustrated. $4.95. The Life of the Marsh explores both the readily visible and minute animals and plants and their niches in the marsh. The beauty and the values of marshland are shown. Although to the casual observer the marsh may appear as an uninviting swamp area, consisting of biting insects and poisonous snakes, those who take a second look, after reading this book, will find that the marsh has much more to offer. The ecological succession from lake to forest is described, explaining that all lakes are doomed to die and that most marshes result from dying lakes or the natural tilling in of coastal waters. Man's importance in upsetting or maintaining nature's balance is stressed. Estab- lishment of marshland refuges are failing to keep up with the destruction of wild- life habitat resulting from land reclamation. Niering points out that reclamation in ,i. C IX.IFORNLA FISH AND QA ME many instances has been performed hastily and unwisely. The wetland areas in the National Park system and the nation's wildlife refuges are discussed briefly. Endangered wetland species mentioned include the Venus's-flytrap, the dusks seaside and Cape Sable sparrows, and the alligator and crocodile. The text is suited for both layman and professional although, unfortunately, scientific names were not included. A glossary is provided, as well as a short bibliography. The photographs and illustrations are excellent. Whether the reader ever visits a marsh or not, the 1 k makes for worthwhile and enjoyable reading. Hopefully those who are in- volved in land reclamation work will be exposed to The Life of ihe Marsh. — James I. St. 1 mant. Handy Medical Guide for Seafarers, Fishermen, Trawlermen, Yachtsmen By R. W. Scott; Fishing News (Books) Ltd., London, 1969; ix + 86 p., illustrated. =1.10.0 cloth, £l.0.0 paper. This booklet is appropriate for ready reference in many isolated situations, but it is not intended to replace or supersede the knowledge and use of more compre- hensive texts on first aid or medicine. The book's langauge is colloquial and readable. The inclusion of English idioms in various chapters does not detract from the American reader's understanding of each section. — Charles H. Turner. printed in California office of state printing 79574 — 800 10-69 5,300 ?? c ' TP yig *? X > 2 " f} §5 o Sia