CAUFIDRNI^ FISH™ GAME "CONSERVATION OF WILDUFE THROUGH EDUCATION" California Fish and Game is a journal devoted to the conserva- tion of wildlife. Its contents nray be reproduced elsewhere pro- vided credit is given the authors and the California Department of Fish and Game. The free mailing list is limited by budgetary considerations to persons who can make professional use of the material and to libraries, scientific institutions, and conservation agencies. Indi- viduals must state their affiliation and position when submitting their applications. Subscriptions must be renewed annually by returning the postcard enclosed with each October issue. Sub- scribers are asked to report changes in address without delay. Please direct correspondence to: CAROL M. FERREL, Ed/for Department of Fish and Game 722 Capitol Avenue Sacramento 14, California Individuals and organizations who do not qualify for the free mailing list may subscribe at a rate of $2 per year or obtain indi- vidual issues for $0.75 per copy by placing their orders with the Printing Division, Documents Section, Sacramento 14, California. Money orders or checks should be made out to Printing Division, Documents Section. u I] VOLUME 47 JANUARY, 1961 NUMBER 1 Published Quarierly by the CALIFORNIA DEPARTMENT OF FISH AND GAME SACRAMENTO STATE OF CALIFORNIA DEPARTMENT OF FISH AND GAME EDMUND G. BROWN Governor FISH AND GAME COMMISSION JAMIE H. SMITH, Presidenf Los Angeles HENRY CLINESCHMIDT, Vice Presideni J. H. RICHARDS, JR., Commissioner Redding Sacramento CARL F. WENTE, Commiss/oner WILLIAM P. ELSER, Commissioner San Francisco Son Diego WALTER T. SHANNON Director of Fish and Game CALIFORNIA FISH AND GAME Editorial StafF CAROL M. FERREL, Editor-in-Chief.. Sacramento JOHN E. FITCH, Editor for Marine Resources Terminal Island ELTON D. BAILEY, Editor for Inland Fisheries Sacramento MERTON N. ROSEN, Editor for Game Sacramento DONALD H. FRY, JR., Editor for Salmon and Steelhead Sacramento TABLE OF CONTENTS Page Mortality Kates and Movement in the Channel Catfish Popnlation of the Sac- ramento Valley George W. McC amnion and Don A. LaFaunce 5 Observations on the Natural Spawning of Eastern Brook Trout .... . . Paul R. Needham 27 Correlation of Food Habits and Abun- dance of Waterfowl, Humboldt Bay, California .... Charles F. Yocorn and Mathew Keller 41 King Salmon Spawning Stocks of the California Central Valley, 1940-1959 . . Donald H. Fry. Jr. 55 Report on a Co-operative, Preseason Sur- vey of the Fishing Grounds for Alba- core (Thiomus, gcrnio) in the Eastern North Pacific, 1959 . Willian} L. Craig and Joseph J. Graham 78 Construction and Operation of a Small Boat Trawling Apparatus ... . . Wayne J. Baldwin 87 The First Recorded Mass Stranding of Pelagic Red Crabs, Pleuroncodes pla- nipes, at Monterey Bay, California, Since 1859, with Notes on Their Biology Peter W. Glynn 97 The External Morphology of the First Zoeal Stages of the Crabs, Cancer magister (Dana), Cancer antennarius (Stimpson), Cancer anthonyi (Rath- bun) . Robert D.Mir 108 Note Waterfowl Botulism Outbreak in San Jacinto Valley, Riverside County, California .... Harold M. Hill and Laurence M. Graham 118 Reviews 115 (3) MORTALITY RATES AND MOVEMENT IN THE CHANNEL CATFISH POPULATION OF THE SACRAMENTO VALLEY' GEORGE W. McCAMMON AND DON A. LaFAUNCE Inland Fisheries Branch California Department of Fish and Game INTRODUCTION Channel catfish (Ictalurus pimctatus) were first introduced into the Central Valley of California in 1891. An unauthorized introduc- tion also took place sometime between 1925 and 19:30. Each of these introductions occurred in the northern part of the Central Valley, in that major division known as the Sacramento Valley. The approxi- mate north and south boundaries of the Sacramento Valley are the cities of Redding and Stockton, respectively. The first authentic record of capture of the species was not made until 1942, and from that year until 1950 reports of observations of channel catfish were infrequent. During that period, the sport catfish catch of the Sacramento Valley was dominated by the white catfish (Ictalurus catus). The browu bullhead (I. nchulosus) and black bull- head (I. melas) were present in the area, but their contribution to the fishery was of minor importance. About 1950, channel catfish began appearing in substantial numbers in the s]wrt fishery of the lower Sacramento Valley. Although estimates of the total catch were unavailable, it was evident by 1954 from news- paper reports and field observations by California Department of Fish and Game personnel that a channel catfish fishery of major proportions had been established. The large size of the fish enhanced the popularity of the fishery. Specimens weighing from 5 to 10 pounds were caught frequently, with an occasional individual of 15 to 20 pounds appearing in the catch. The fishery area is restricted in size and roughly triangular in out- line, with Marysville on the Feather River, Colusa on the Sacramento River, and the confluence of the Sacramento and Feather rivers at the apexes (Figure 1). Sutter Bypass, a flood control channel possessing permanent sloughs, traverses the area from Colusa to a point immedi- ately upstream from the mouth of the Feather River. Angling use is greatest along the Bypass sloughs. An exploratory tagging experiment was undertaken in the spring of 1955 to gather information pertinent to the management of the new fishery. The primary objectives were: (1) to ascertain the movements 1 Submitted for pubUcation May, 1960. Thi.s work was performed as part of Dingell- .lohnson Project California F-2-R, "A Study of the Catfisli Fishery of California", supported by Federal Aid to Fish Restoration funds. (5) 6 CALIFORNIA FISH AND GAME of the fish; and (2) to obtriiii i-cliahlc est iiiiatcs of mortality rates within the jjopulation. This jjapcr presents the results of the study. ACKNOWLEDGMENTS Speeial thanks are due eowoi-kcfs \"iiii-riit ('alania and Ross Wa<>-- fi'ouer, -wlio assisted with field opt'rations. 'I'hc autliors are indebted to Dr. W. E. Kieker of the Fisheries Keseai-ch Uoai-d of Canada for su«:j;estions on ihe presentation of the nmi'tality data, 'i'he assistance of the Twin Cities Kod and (lun Cluh in handling- the prize drawiuf? for taji' returnees is frratefully aekiiow leilucd. ('lilTa Coi-son ]ii'epared the figures. TAGGING METHODS A total of 7!)7 fish was ta^fjed : If)!) in the Saei'amento Kiver at the mouth of Sacramento Sloujih, one-half mile uj)stream from the mouth of the Feather River; 200 in the Sacramento River at the mouth of P>utte Creek, five miles downstream from Colusa; 200 in the Feather River about five miles below^ Marysville; and IDS in the West Cut of Sutter By])ass at the llijihway 40A causeway. All tad durino: April and .May. 1955. The fish were ea])tured by means of fyl\e nets, as deseribed by Pelgen and McCammon (1955). Nets were fished for four or five days before being raised. Extensive catfish trapping in other California waters has demonstrated that several days of undisturbed fishing ai-e rerpiired to produce optimum catches. The condition of all fish was excellent at time of tagging. The disk-dangler tag was used exclusively. The construction of this tag and the method of attachment on catfish have been described by Pelgen (1954). It is the most reliable tag available for catfish. Fork length, to the nearest one-tenth of an inch, was recorded for 794 tagged fish. The mean length was 12.1 db 0.1 inches, with a range from 6.8 to 22.1 inches. Length frequencies of fish tagged in each of the four areas are shown in Tables A-1 tlu-ough A-4 of the Ai)pen(lix. Some size selection was exercised. A niiiiiiiiiini tagging length of 7.0 inches fork length w^as established; howevei-. an oversight resulted in the tagging of oim> 6.S-iiieli s]iecimen. As shown in Tahh' 1. the mean lengths of three nf the saiui)les were approximately equal, while the catfish lagged in Sutter Bypass were appreciably larger. A)i analysis of vai'iance computation demonstrated significant differences ])etween the foui' means at the 5 ]iercent level (F = 146.8; d.f. 'A. x; P < 0.05 1. A multiple range lest (Duncan, 1957) at the 5 percent |e\cl. I'evealed sigiiitii-ant differences between all file means exce])t those foi' fish from Sacramento Slough {m =: 11.1) and the mouth of Putte Creek ini — 10.8). Xonraudom sampling, due to nonrandom dist i-ibution of Ihe fish, proljably accounts for these dif- ferences. The pi-esence (if larger catfish in the Py]")ass is discussed in a subsequent section of this report. Inasmuch as tag recoveries were de|)endent upon voluntary returns from indixidnal anglers, several metluids of stinndating auLiler interest were employed. Posters infoi'ining the public about the State's catfish tagging |)rogi-am. as described by Pelgen (1954), were distributed throughout the study area at poi)ular fishing spots, fishing resorts, and CATFISH MORTALITY AND MOVEMENT TABLE 1 Comparison of Lengths of Channel Catfish Tagged and Returned Fish tagged Fish returned Tagging location Number Range in fork length (inches) Mean fork length (inches) Number Range in fork length* (inches) Mean fork length* (inches) Sacramento Slough Butte Creek mouth Feather River Sutter Bypass, 199 200 198 197 6.8-19.2 7.6-18.9 7.7-20.9 9.4-22.1 11.1 10.8 11.7 14.9 53 58 60 55 8.1-17.6 8.0-18.9 8.8-20.9 9.5-21.9 11.2 11.4 12.3 15.3 Totals 794 6.8-22.1 12.1 226 8.0-21.9 12.5 * Lengths at time of tagging. sportino- goods stores. The address to Avhich the angler was to mail the tag and recovery information was printed clearly on each tag, and a commendation card bearing a brief history of each fish was sent to every person who returned a tag. Anglers who reported tag recoveries within the first 12 months of the study were eligible for a prize draw- ing sponsored by the Twin Cities Kod and Gun Club of Yuba City. This drawing consisted of $200 in cash prizes, appropriated to the club by the Sutter County Board of Supervisors from county fine monies. RESULTS General ■ Anglers returned 228 tags (29 percent) over a period of four years, including two from fish that had not been measured at the time of tagging. An additional seven recoveries were made by Department of Fish and Game personnel. The latter recoveries were used for deter- mining fish movements only. Tag returns are grouped according to the number of months elapsed since the date of tagging, divided into 12-month periods. For example, a fish tagged May 15, 1955, and recaptured April 30, 1958, had been at liberty 35-|- months and is therefore assigned to year 3 of recovery. Annual recoveries were : first vear, 146 ; second year, 54 ; third year, 20; and fourth year, 8 (Table 2; Appendix, Tables A-1, A-2, A-3, A-4). TABLE 2 Summary of Angler Tag Returns from Channel Catfish in the Lower Sacramento Valley Number tagged Tag returns Tagging area First year Second year Third year Fourth year Totals Sacramento Slough - 199 200 200 198 33 34 33 46 14 20 13 7 4 2 12 2 2 2 4 0 53 58 Feather River 62 Sutter Bypass.- 55 Totals 797 146 54 20 8 228 8 rAT.TFOHXiA KISH AXI) OAMK A chi-SfiUMrc tcsl ;i1 lllc ■') pi'l'rriil |c\c| |-c\c;i Ice 1 a si at isl ica I ly si^liifi- '/aiit size (lift'crciu'c. at lime oi' Ui^i-^inji', Ix'twceii nil fish 1a<:jr<'(l hikI those fi-om which 1a<:s wci'c returned ('{'ahh' 1 . ('lose inspection of the (hila (iisch)se(l that tliis dilfei-eneo was a rcsiih df: (1 ) (lis|)ro])()r- t innately fewer returns from fish less than D.O inches Idik Icniilh (lurin- when it is i-eco-iiiized that the fishery was di- rected ])rin)arily toward lar' mortality or loss of ta{is in the T.O-H.D-inch size •ifi'ouii is i-eject(Hl as a possible I'eason, since fish from this group were returned in proportionate nuiid)ers after the first year. Second, the un- ex])eete(lly hi thriH^ river tagging locations. AVhile the rate of exploitation is considerably greater in the Bypass than in the rivers (Table 2), thus increasing the probability of capture of any fish venturing there, the fact remains that a large percentage of the population is attracted to the area. The attraction must be potent, for access is impeded on the north end. To enter the Byjiass, the fish must pass through underground conduits. The forces that in- fluence this affinity for the Bypass are not understood. AVarmer water temperatures or a more abundant food supply are possible explana- tions. The Bypass has a reputation among anglers for proilucing larger fish than do the rivers, and this concept is substantiated to some extent by the size distribution of the fish tagged there. As mentioned previ- ously, the fish tagged in the Bypass were significantly larger than those taggetl in the river. The lengths of fish tagged at the three river stations that moved into the Bypass during the first year were com- pared, by means of a /-test, with the length distribution of first-year recaptures from outside the Bypass (Ap])endix, Table A-5). The dif- ference was significant at the 5 percent level. An explanation for the apparent greater tendency of the larger channel catfish to move into Shifter Bypass is not available. No suggestion of a regular, seasonal migration was evident in the tag recovery data. However, it would be difficult to detect a sea :onal pattern of movement unless many more fish were tagged, because angling is concentrated in the sunnner months. The annual distribution of angling pressure, based on tag recoveries during the four years of the study, is shown in Figure 5. During December, 1955, oidy seven months after tagging was com- pleted, a major flood occun-ed in tiie study area. The heavy flows, exemplified by the passage of KXi, ()()() cnbic feet of water pei- second throuuh Sutter Bypass (California I)ei)artment of Water Resources, 1!)57), may have profoundly affected both movement and mortality within the population. Thus, the study may have been subjected to atypical conditions. Another expei-iment shoukl be carried out to either corroborate or refute the data presented here. Subsequent tagging should include an appro])riate technique for obtaining an accurate measure of nonresponse by anglers who caiitui-e tagged fish. Growth of Tagged Fish No attempt was made to detei'mine tlie gi-owtli rate of the tagged fish, since there are no means of separating accurate and inaccurate ans>ler measurements. However, most of the anglers who returned tags 14 CALIFORNIA PIRH AXD r; A:\rE 56 52 48 44 40 CO 36 I 32 I— UJ o: 28 < 1- 24 20 16 12 e 4 1 — ., , , 1 1 1 1 ' 1 — , ll 1 1 1 1 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC FIGURE 5. Monthly recoveries by anglers of tagged channel catfish in the lower Sacramento Valley, California, 1955-59. during tile secoiul, tliird, and i'ourlli years gave iiu'a.surement.s that far exceeded the size of the fish when tagged. In one instance, an angler reported capture of a specimen on July 17, 1957, with a total length of 21 inches and weight of 5 ])ounds, 11 ounces. The angler included a snapshot of the fish, with tag still attached, that indicated his measurements were reasonably accurate. The fish was tagged on May 10, 1955. at a fork length of Mli) inches. Thus, this fish grew about six inches in slightly over two years (total length exceeds fork length by apjjroximately two inches in channel catfish of this size). Judging from untagged channel catfish growth rate data fi'om other waters, this rej^resents excellent gi-owth. Although the growth rate of untagged fish in this population has not been determined, there is some evidence that growth is very rapid. Mr. (instav (Jeibel (personal connnnnication ) of the Central X'alhn--; State Fish llatcjiery at Elk Grove has rc|)()i-tcd tliat fish prociifi'il from this population for brood stock are often immature at total lengtlis of 20 to 21 iiu'hes. in most chainu'l catfish populations. mat\ii'ity is attained at api)i-oximately 15 inches total lenglli. Also, limited observa- tion of pectoral spine sections lias shown that some fish I'eacli fork lengths of IS to lH indies in only foni' gi'owing seasons. In ( )klahoma, channel catfish are nsually 1().4 inches long, total length, aftei- five years (Hall and Jenkins. 1952). CATFISH MORTALITY AND MOVEMENT 15 Survival and Mortality Rates Uncorrected Data The following- calculations of survival and mortality are based wholly on concepts and methods presented by Ricker (1958). His methods are reiterated for the benefit of readers who are unfamiliar with the mathe- matical procedures and concepts that underlie them. The rate of decline in the annual recaptures of tagged fish was used to obtain two estimates of the mean annual survival rate (s) . These methods presume that (1) the tagged fish are subject to the same fishing and natural mortality rates as the untagged fish ; ( 2 ) the tagged fish are distributed uniformly in the population; and (3) annual fishing and natural mortality rates do not change appreciably during the study period. A weighted estimate of the annual survival rate was computed from the ratio of each year's recoveries to the preceding year's, i.e.: s = Ro -\- Rz -\- Ra 54 + 20 + 8 Ri + R2 + Rs 146 + 54 + 20 = 0.373 An unweighted estimate of survival Avas obtained by fitting a linear regression line to the common logarithms of annual recoveries (Figure 6). The antilog of the slope is then equal to the mean annual survival rate. The regression coefficient for the slope was — 0.42151, representing a survival rate of 0.379. The close agreement between the two estimates and the close fit of the regression line indicate that survival did not vary significantly from year to year. The unweighted estimate of tr UJ > o o 12 3 4 YEAR OF RECOVERY FIGURE 6. Logarithms (straight line) and actual numbers (curved line) of annual recoveries of tagged channel catfish in the lower Sacramento Valley, California, Ifi CAl.iroWMA KISII AND (iAME ()J)7!( is coiisidcri'd sat isfadory \\)]- rui'tlirr i-(tiiipiila1 inns ol' ixipiilal ion parMiiictcrs. The Miimial total iiioiMality rate is thus n = l — ().;{7!) = OJi'il. This cstiiiialc is h('lic\C(l to he essentially freo from "Type B " systematic errors ( Ixieker. llt.'jS ; p. ll!l), such as a coiistaiil i-a1e of tajr loss, a steady i-a1e ol' iiioi-lality aiiioiii: the 1a'THtion. The estimate of total mortality is not influenced by other types of systematic error, such as an initial tafr^'ill^'■ nioiiality oi- nonreportiufi: of ta<; recoveries. When total moiiality is obtained from markiufj experiments, it is jiossible to bi-eak down this pai-ameter into its components: (1) deaths from fishin;:-, and (2) (h'atlis from natural causes. These mortalities can he (\\])resse(l in three ways: (1) animal expectations of deaths from fishinnst' is pi'cscntcd in Taljlc '■'. A licst ljih'ss ciiiici'minii' the tiMic rate of iio!ii'('s])()ns(' iiiijilit he 40 pcrcciil. At tliis Icxd. ii =: {).2!)8, r = ().;{2:}, j) = ().4()6, and (j = 0.504. TABLE 3 Uncorrected Estimates of Mortality in the Channel Catfish Population of the Sacramento Valley, 1955-59, with Corrected Estimates for Possible Levels of Angler Nonresponse Mortality expressions Mean annual survival Mean annual total mortality Instantaneous mortality rate Instantaneous fisliiuK mortality rate Instantaneous natural mortality rate Annual fisliinti mortalit.y rate Annual natural mortality rate .-Annual expectation of deaths: I'rom fisliind From natural causes Uncorrected Annual percentage of nonresponse estimates 0.30 0.40 0.50 0.379 0.379 0.379 0.379 0.621 0.621 0.021 0.621 0.970 0.970 0.970 0 . 970 0.284 0.40,5 0.466 0..567 0.686 0..56.5 0..504 0.403 0.248 0.32.5 0.372 0 . 433 0 . 497 0.431 0.395 0.331 0.182 0.2.59 0.298 0.363 0.439 0.362 0.323 0.258 Tlic foregoing oslimatcs an' based on the assiniiption that the ciitii-c h)t of tagucd fisli was ('(pially vnlncrahic. This is not the (•ast^ As nicii- TJoned earlier, the tagged fish that were h^ss tliaii !).() inehes long, fork leiigtli, were incompletely recruited dui-ing the first reeovery jieriod ; hence, their rate of fishing is sonirwliat less than the (h'tinitive ivite. The 7H fish that were under !).0 indies foi-k length when tagged were therefore exchuled from all siir\i\al and mortality computations. Nor- mally, the correct procedure would he to eliminate these iiiromiiletely i-ecruited fish at the vei-y beginning of Ihe eoniputal ions, prior to the eoiisidei-atiou of other erroi's. However, in this case the authors be- lieved that it would be more effective 1o present all corrections for vari- ations in vnlnei-ability in the same section. The exclusion of the ])arliall.\ xuliieiable lisli iii;M-ea:.ed a by only 1 pei'ceiit. The error caused by fishing during yeais nf ii'criiil nieiil is appai'eiitly serious only when a lai'iic percenlage of the taii^cd popula- tion is not yet fully recruited, oi' when i-ecrnit iiieiil extends (inci- a pei'iod (if se\ eral years. A more sei-ious diU'erem-e in xiilnei'ability is caused by the high angling intensity in Sutter li.xpass. l'"or instance, the estimati' of ii . corrected for 40 jx-iceut nonresponse. for fish tagged in the ilypass is O..SHH. while the combined estimate tOi' cdiiipletely recinited fish tagged in tim Saci'amento and Fealher I'ivei-s is only 0.."{04. It is pidbable thai the great variation in rate of fishing makes our oxciall estimate of the fishing mortality I'ate greater than the definili\e lale. since the original CATFISH MORTALITY AND MOVEMENT 21 calculations gave equal weight to the returns from each of the tagging localities. If one-fourth of the stock were present in the Bypass when the fish were tagged, then the Bypass returns could logically be weighted ecpially with the other tagging locations. However, it is ex- tremely doubtful that the uumber of vulnerable fish present in the Bypass at any given time approaches one-quarter of the total stock. Since the proportion of the stock that was present in the Bypass at the time of tagging is unknown, it is not possible to adjust the calcu- lations so that the Bypass returns are weighed correctly. Therefore, the fish tagged in the Bypass were eliminated from consideration, and appropriate parameters were recalculated from recovery data that were obtainecl from completely recruited fish tagged in the rivers only. These data include the fish that were subsequently caught in the Bypass. The final estimates of population parameters adjusted for 40 percent u our espouse and differences in vulnerability are : Mean annual survival = 0.4-10 Mean annual total mortality r= 0.560 Annual expectations of deaths from fishing r= 0.304 Annual expectations of deaths from natural causes = 0.256 Instantaneous mortality rate ^ 0.821 Instantaneous fishing mortality rate ^0.445 Instantaneous natural mortality rate = 0.376 Annual conditional fishing mortality rate = 0.359 Annual conditional natural mortality rate = 0.314 Since the growth rate of the channel catfish is unknown , the rate of fishing that will produce the maximum sustained yield per unit weight of recruits cannot be determined. However, judging from the yield curve for Type B growth of Tester (1953), it appears that the present value of p is providing a sustained yield in weight that is close to maximum. SUMMARY 1. A substantial sport fishery for channel catfish developed about 1954 in the rivers and sloughs of the lower Sacramento Valley' of Cali- fornia. A tagging experiment was begun in April, 1955, to obtain data on movement of the fish and mortality rates operating on the usable portion of the stock. 2. Disk-dangler tags were attached to 797 channel catfish during xVpril and May, 1955. The fish were released in approximately equal num- bers at four locations. They ranged from 6.8 to 22.1 inches in fork length, with a mean length of 12.1 inches. 3. Anglers voluntarily returned 228 tags during the following four years. Annual recoveries Avere : first year, 146 ; second year, 54 ; third year, 20 ; and fourth year, 8. 4. The locations of angler recaptures indicated that the population is essentially restricted to a relatively small area, circumscribed by Colusa on the Sacramento River, Marysville on the Feather River, and the confluence of the Sacramento and Feather rivers. Movements within this area were extensive; however, only 13 percent of the 22 CALIFORNIA FISH AND GAME total i-ccovcric's ^v(.'l•(' rccoi-dcd Iroui oiitsitlc liic area. The tagji'ed eatfisli (liiiioMstratod a dofinite propensity for mi*?ration into Sutter l^ypass, a flood control cliainicl willi pcrinaiiciit slonphs that traverses the fisliory area. 5. Estimates of survival and iiinr1;dily were l)ascd on concepts and ])ro- cednres jireseiitcd by Hickcr (l!)r)S). These estimates, corrected for an assumed rate of noiireportinj; of tap: recoveries by anglers of 40 percent and for variations in vnlnerability were: s ^ mean annual survival ^0.440 a := mean annual total mortality ^0.560 t r= instantaneous mortality rate =0.821 p = instantaneous fishing mortality rate = 0.445 q = instantaneous natural mortality rate _^ := 0.376 w r= annual expectation of deaths from fishing ^0.304 V = annual exj^ectation of deaths from natural causes = 0.256 m = annual conditional fishing rate = 0.359 M = ainuial conditional natural mortality rate =: 0.314 The current rate of fishing appears to lie providing a sustained yield in weight that is near maximum. REFERENCES r.iitl«T. Robert L. l!(r»7. The rtevelo])nu>iit of a vinyl plastic subcutaiiet. : P'isheries no. 75, 48 pp. I»uncan. David B. 1957. Multiple ranj^e tests for cori-el.iti'd .-iiid lieteroscedasf ic means. P.iometrics, vol. 13, no. 2, pp. 1(54-1 7(5. Hall. Cordon E., and Rol)ert M. .Jenkins 1952. The rate of growth of ehannej calfisli. I itiilurux /ik net a Ins. in (tklahnnia waters. Okla. Acad. Sci., Proc. vol. :',:{. p|>. 121-129. Mr-Cammon, Ceorse W. 19.5<;. A t:igj;in^' experiment witji (iianHci cattish ( 1 rtnliinis iniiutatus) in the lower Colorado River. Calif. Fish and (Jame, vol. 42. no. 4, pp. 323-335. .Mnllan. .lames W. 1959. Pi-olialde I'fCcci i\ cness nf t:i^ reiiorliu;; from ti-oiit stncked in Iwo .Massa- chusetts stream dr;iiiia;,M's. .Mass. IHv. Fisli .iiul (J.ime. l."! jip. (.Minico.) Pelfren. David E. 1!I54. Pro;,'ress repurl on Die ta^'^'in^' nf wliitc cittish (I'lnhinis ciitns) in tjic Sjicramento-S;in .Inai|iiin Delta. Calif. Fish and (Janic. vul. 4(1 no :! pp 313 321. I'el^en. David E., and Ceorffe W. .M. ( '.iiinnnii 1955. Second iiro;;ress report on the ta^r^'in!: i<( white cattish ( fitiihtnis mtus) in the Sacramento-San Joaquin Delta. Calif. Fish .and Cainc \<.| 41 n() 4 pp. 2<;i L'CK. lii.k.r. W. E. 195S. Hiindliook of cnminitai ions I'.ir lii..l(.;;i.;il statistics of tish inqmlat inns. Fish K.'s. I'.d. (':in:i:s. Each lofj was ])laced so that the line of nails where the canvas was fastciKMl came in the middle of tlieir npsti'caii) sides. The loys were secnrely fastened to the stream- bed by nailin()r()iis cuttinji- niovemeids in ra])icl succession, at the rate of about three or four a second. The female tests or feels the effect of her cutting by means of her anal, caudal and pelvic fins. ..." The cuttin bi-ook ti-out app(>ared similar in all i-espeets to that of the Atlantic salmon. The trembling or (luivering movements obserA-ed in conriship have been showr by Fabricius and Gustafson (1954), to ac1nall\- he yew swift undtdations. This was deterndned fi'oni slow-motion pictui-es. They say (p. 74) that. "... waves of lateral contoi-tions travel rapidly from the cranial to the caudal end of the body." During nest-c-utt in^ ojDerations the tagged male accompanying the female bei-ame highly annoyed at a five-incdi male eastern brook trout that was jx'rsistcMitly trying to get into the nest area. The annoyance a])parently canu^ to a head when he seized this small fish across the back between his jaw's, released him for a moment, and then seized him again in the same fashion ami shook him miudi like a dog shakes a rat. It a])])eared fii-st that he was going to eat him, but this did not occur. Close observation of the small lish next to the window did not reveal any teeth marks or any injury. The attack did not daunt him in the least, for he eontinued to harass the large male. As noted by Needham and Taft (IfCUi. Smith M!m i. and other workers, breeding activities continued both day and idght. Changes in the shape and size of the redds were noted from day to day — changes which conld only have been made at night when observations could not be made. THE SPAWNING ACT This spawning act was fii-st seen on (h-tober 1(J, 1!)59, at 12.40 i).m. The female Avas observed to droj) her anal fin deeply into the pit, arch- ing her tail at the same time. The male promptly took his ]>lace beside her. Both opened their motitlis wide and appeared to 1i-emble while milt and eggs were emitted simultaneouslv, the entire act lasting no longer than about one secoiul. Xone of the other males present were seen to dart into the nests on the opposite side of the female and share in the sjiawniug act. Smith (1941 ) reports observing two males sharing in the s])awni]ig act in one out of three spawning acts observed by him. Because the male took his position on the right side of the female between the w'indow and the female, and because of the white (doud of unit extruded, it was imjiossible to observe the eggs falling into the bottom of the nest. However, the })ale yellow eggs could be seen clearly in the bottom of the pit after w'ater cuirents had washed away excess milt. The ndlt was observed to hang in the current eddies in the pit. spreading laterally and even npstream a bit before finally disappear- ing. The bottom of the pit was soiiu' foui- imdu's below the edges of the nest. This provided a pocket of (pnet water, wlieie the eggs were dropped and where fertilization must have occurred almost instantane- ously. Ilobbs (ID.'iT), Cramer (1!)4()), and Smith (lil41)— all observed the cloud of milt, but only Smith noted the sj)read of the milt ui)sti-cam and sidewise in the nest because of current eddies. BROOK TROUT SPAWNING 33 The position taken by the female in the actual spawning act was termed "a crouch" by Jones and Ball (1954) in observations of the spawning of Atlantic salmon and brown trout. They also observed that the orgasm lasted only one or two seconds in brown trout, while that of the salmon required approximately 10 seconds. About a second was required for completion of the act in the eastern brook trout; and in this respect, they parallel bro^\^l trout. Fabricius and Gustafson (1954, p. 99), in their description of the spawning act of the closely related Arctic char SalveJinus alpinus, state that when ready to spawn, "the female shows a signal movement which could be called anchoring. She suddenly stops in the center of the nest ])it, lowers her anal fin down into some crevice in the bottom, bends her body backwards, trembles and opens her mouth. The male responds by swimming up parallel to her, and both fishes swim side by side across the pit in a spawning act, squirting out their sexual products." On the same page they also state that, "After 1 to 5 successive spawn- ing acts the female performs snake-like undulating movements," to cover the eggs with gravel. In contrast wdth their observations, the pair of eastern brook trout observed in Sagehen Creek remained stationary over the nest pit during the spawning act, not swimming over the pit while discharging the sex products. Furthermore, the pair spawned onlj^ once, after which the female immediately covered the eggs, using the undulating movements described below. *& POST-SPAWNING BEHAVIOR Immediately after spawning the female eastern brook trout began what may be termed a "post-nuptial" dance. This is beautiful to watch and is quite a different method of covering the eggs than that used by rainbow or steelhead, cutthroat, or Atlantic salmon. While Smith (1941) described this process from a blind above the w^ater, I am able to add more details. After dropping the eggs, the female immediately began a sinuous, weaving motion, using the ventral tips of the caudal and anal fins to roll gravel gently into the nest over the eggs that could be clearly seen on the bottom of the pit. The motion consisted of weaving her head and caudal fin gently back and forth in the same direction, with the head raised high over the redd and the anal and lower tip of the caudal working over the gravel adjacent to the eggs. That she knew precisely the spot where she had dropped the eggs, was evidenced by the fact that not once did she work the caudal directly over the eggs themselves. Her anal fin was curved into a somewhat shovel-like position into the gravel and pushed pebbles slowly into the egg pit. The gravel was small, mostly- around one-quarter of an inch in size, and usually only a single pebble or two moved with each in- dividual sweep. She had the eggs completely covered in four minutes. She circled the pit in this manner with the head directed outward and her caudal portions inward, near but not over the eggs, for around half an hour. After 30 minutes, and after she must have known the eggs were deeply covered, she would occasionally begin the charac- teristic digging or cutting movements upstream some eight inches above the pit where she last deposited the eggs. By 1.45 p.m., she was regu- larly cutting a new nest and had ceased egg-covering movements. 2 — 28642. 34 CALIFORNIA FISH AND GAME AVliile covering the eggs, she was most aggressive in driving away iinniature eastern brook and rainbow trout. She would attack them viciously at times, opening her mouth to bite them. The male, on the other hand, seemed quite docile during this period and hung around the downstream edge of the nest doing little to aid the female in di-iving other fishes oif the nest area. Some 10 to 15 minutes after the .spawning act, the male that had mated with her departed for some other place in the pool while she continued to cover the eggs. During the process of covering the eggs, one of the large male brown trout came cruising by the redd. She ignored him, but she drove off all other fish that attempted to come near. The next morning the redd was beautifully iKunded and topped with small pebbles. None of the other fish in the pool were allowed close enough to the nest by the female at any time to secure eggs. This observation would tend to give assurance of minimal losses by predation during the spawning process. Some of the smaller males were freciuently aggressive, and much of the female's time was spent fighting them off. One of the small males was observed to grab her caudal peduncle in his jaws, even though he was much smaller in size. This I judge to be part of the courting act rather than an act of aggression. The actual spawning act by the same pair was observed again at 11.05 a.m. on October 11. This time the nest had been dug about 12 inches upstream from where she spawned on October 10. Observations were started at 10.50 a.m. It was possible to tell that she was almost ready to spawn because she Avas feeling deeply into the pit with her anal fin and still turning on her side, and digging once or twice a minute. The same behavior occurred after spawning as was observed the day before. The female immediately started the beautiful undulat- ing motion to cover the eggs. The same tagged male mated with her and this time he remained only three or four minutes, after which he departed. After spawning he became far less aggressive towards other males. Again after her mate departed, the small eastern brook males, some five of them, gathered around evincing interest in her. Once the female, in between undulations in pushing the gravel over the eggs, swam over and rubbed her fins over the male with whom she had just mated, seemingly to perform an act of courtship toward him. No other males were in on the spawning process other than the large male that attended her at all times, except immediately after spawning. The smaller males in the ])()(»1 became quite excited just before the actual spawning act and vigorously attempted to intrude into the nest area. Wliat attracted them is not known, but possibly it was the motions of the female that indicated that spawning was about to occur. In any case, the male was kept busy driving smaller males away. On October 11, she had deposited her eggs in much larger gravel but, even so, had no difficulty in covering them deeply. She never turned on her side and cut vigorously in the area in which the eggs were laid, altliough she would occasionally go through a sort of half- hearted cutting motion a foot or so upstream from the point where the eggs were deposited. BROOK TROUT SPAWNING 35 WATER TEMPERATURES DURING SPAWNING PERIOD Air and water temperatures are continuously recorded at Sagehen Creek with a two-pen, Taylor recording thermometer. Daily maximum and minimum water temperatures between August 31 and October 25 are presented in Figure 3. Highly-colored male brook trout were ob- served in the tank pool as early as September 15. Peak of spawning occurred between October 1 and October 15, after minimal water tem- peratures had dropped to between 37 and 44 degrees F. Daily mean water temperatures ranged between 43 and 46 degrees F. during this period. It is my observation that male trout mature sexually before females, and if the date of appearance of ripe males in Sagehen Creek is taken as the start of the spawning season, then September 15 could be considered the beginning of breeding in 1959. Female brook trout stayed near the redds until around October 25, in the post-spawning period after the males had lost interest and departed. The full spawn- ing season could be estimated to run from September 15 until October 25. In Figure 3, it will be noted that a rapid drop in temperature oc- curred starting on September 15. This may have served as a releasing mechanism, for spawning activities were initiated immediately after- ward. -T— I — r—r— ] — I — I — r- Aug Sept. Sept. Sept. Sept. Oct. Oct. Oct. 31 6 13 20 27 4 II 18 FIGURE 3. Water temperatures— Sagehen Creek August 31 to October 25, 1959. Oct. 25 Fabricius and Gustafson (1954) noted that the Arctic char spawned at temperatures ranging between 38.3 and 54.5 degrees F. (3.5 and 12.5 degrees C, respectively) ; Jones and King (1949), in work on Atlantic salmon, reported that spawning took place between 36 and 42 degrees F. WATER VOLUME DURING SPAWNING A gaging station is operated jointly on Sagehen Creek by the Uni- versity of California and the Water Kesources Division of the U. S. Geological Survey, using a Leopold-Stevens A35 gage-height recorder. It is located approximately one-quarter of a mile below the observation tank. Discharges between September 1 and October 31 were quite even 36 CALIFORNIA FISH AND GAME i'or the most part, ranging between 1.4 and l.D cubic feet per second (c.f.s.). An early fall storm on September 18 raised the flow suddenly to 6.1 c.f.s., but by September 21 it had dropped back to 1.9 c.f.s. Over the peak of the spawning period between October 1 and 15, discharges ran between 1.7 and 1.9 c.f.s. In other words, volume of flow was low and even, without any disturbance by severe flooding. DISCUSSION The main environmental factors inducing the appropriate physio- logical condition for spawning in an adult brook trout are day h'ngth and water temperature. Selection of the actual spawning site is deter- mined hy visual stimuli of particle sizes seen by tlie female, possibly coupled with water movements. Actual mating hchavioi-. on tlic other liand, is related to exchange of various physical .stimuli or releasers during fighting and courtship. Clear experimental evidence is presented by Fabricius and Gustafson (1954), indicating that nest-digging movements of the Arctic char {SalveUnus alpinus) may be released by visual stimuli. These workers covered suitable spawning gravel areas with smooth glass plates, and the females performed normal digging movements and spawned only on that portion of the plates that were located over suitable-sized gravel. Large, flat stones laid in the bottom — even though they were not covered by the glass plates — were ignored as spawning sites, indi- cating that gravel size was of major importance. Just what part water movements play in the selection of spawning sites by trout, char, or Atlantic salmon is uncertain. The experiments just cited, as well as those reported by Jones and King (1949 and 1950) and Jones and Ball (1954), were conducted in aquaria or tanks of various types with surface current speeds ranging from 1.0 to 1.5 feet per second. Some half-dozen natural nests of eastern brook trout Avere observed in Sagehen Creek in the open stream below the tank area in the fall of 1959, and all of these were located in fairly rapid currents and usually at the lower ends of pools where there was gravel of suitable size. That this species spawns successfully in lakes (Need- ham and Sumner, 1941) is well known, and the areas selected are usually those gravel beaches where ui>welling seep-water occurs. The reason that most species of trout select the lower ends or "tails'' of pools is because the large amount of water passing through the gravels a'^sures the eggs a constant suyiply of well-a(M-ated water during incu- bation. As pointed out by Fabricius and (iustafson (1954), one of the most important functions of the nest-digging movements is to increase the permeability of the bottom materials by removal of loose, fine materials that would tend to clog the spaces between the stones and thus reduce water circulation around the eggs. Tiiey say (pp. 95 and 96), "deposition of the eggs in a permeable material is secured both by a mechanism leading the female to a place where the bottom has this character, and by instinctive^ moviMuents which fui-ther increase the permeability of the matci-ial at the chosen nest site. The anchoring also cooperates in securiiui' the (h^jMisition of the eggs in a permeable material, foi- this act. wliidi immeditely precedes egg-laying, can be BROOK TROUT SPAWNING 37 performed only at a place where the crevices are so deep that the anal fin of the female can sink down in them." In the "eronch" or "anchoring" of the female eastern brook trout observed in Sagehen Creek, it was noted that once a fairly well-formed pit had been dug, she appeared to test its depth frequently with her anal fin, moving it slowly over the gravel in the bottom by arching her back but without giving the sign stimulus for the actual spawning act. Just prior to the first act, she seemed to push the middle portion of the anterior rays of her anal fin rather constantly, for several moments at a time, against one of the larger stones in the deepest part of the redd. The tip of the fin, in this instance, was out of sight in the deepest pocket. 8he seemed to repeatedly "test" the character of the pit as to depth, width, and other characteristics. Within a few moments after this behavior, the actual breeding act was observed. Dr. J. ^Y. Jones wrote as follows (March 3, I960; personal com- munication ) regarding the use of large stones in a bed by the female : "Trout and salmon females spend a great deal of time placing two or more larger stones in a suitable position at the bottom of the bed in between which the anal fin fits snugly when the female is crouching. I feel certain that the female positions these so that her eggs will pass into the crevice in between these large stones." While the female I observed did not attempt, apparently, to actually position larger stones in the bed, it was noted that she utilized the larger stones already present by carefully making the deepest part of the pit just in front of one or two such stones, and in front of which her anal fin fitted "snugly". This exemplifies the extreme care with Avhich each pit is- prepared by the female for the reception of the eggs. The most complete discussion of the various stimuli involved in breeding of salmonids is found in papers by Fabricius and Gustafson (1954) and Jones and Ball (1954). Fabricius and Gustafson, in dis- cussing the findings of Jones and Ball, point out that while there are mau}^ striking similarities between the behavior of brown trout and the Arctic char, there are also some sharp differences. For instance, the Arctic char and brown trout often bite their opponents. This is also true of the eastern brook trout and also of the Atlantic salmon. Similarly, the brown trout, Atlantic salmon, and eastern brook trout spawn but once in a single pit. and the females begin to cover the eggs innnediately afterward, whereas the Arctic char will perform several spawning acts in each pit. This observation is confirmed in work by Dr. Winnifred E. Frost (1956). She observed that with the eastern brook trout only a single orgasm takes place over a single pit, whereas with the Lake Widermere char (S. alpi)ii{s) two to seven usually occur. Frost also reports the undulating movements used by eastern brook trout to cover the eggs, stating (p. 31), "the female moved stones as big as walnuts with her tail and covered the eggs to a depth of an inch." Both the eastern brook and the Arctic char use similar undulating movements to bury the eggs. The above papers each present different interpretations of courtship behavior, especially with respect to the trembling or quivering movement exhibited. Headers are referred es- pecially to Tinbergen (1951) for the broader outlines of this process of animal behavior. 38 CALIFORNIA FISH AND GAME In small streams, it is ea«y to locate aiul to count reLlcLs. The sliallow gravel areas in which the females d\g are quite noticeable to the eye once one becomes familiar Avilli llicii- jippearance. All sediment and silt is Avashed away, and they a])|)(';ii' when completed — as small, nicely ronnded piles of clean j^ravel. Unworked areas, by way of contrast, appear undisturbed and darker in color from fine layers of sediments on the gravels. Oftentimes one can locate spawning fish sim]ily by the noise made by the females during digging opei-atioiis. I have located redds of steelhead, cutthroat, brown and eastern brook trout by the noisy splash- ing actions of females during breeding. Much more thoi-ough information is needed on such details as water volumes and direction of flow through redds, size and position of gravels selected, and water temperatures during spawning. Of greater importance would be information dealing with popnhition densities on spawning areas in relation to sulisecpieut liatching and snrvival of young. Where fish are crowded on limitetl gravel areas, and where their density is such that late-spawning fish may dig up and destroy or make accessible to predators eggs laid by early spawning females, heavy losses result. ]3y knowing in full the spawning requirements of each species and the optimal densities in relation to space and survival, it should be possible to install suitable spawning beds — or improvements to them — that would be utilized by the fish where such facilities are lacking, scarce, or crowded. Proof that trout can be induced to use artificially constructed redds is presented here and in a number of the papers cited. ACKNOWLEDGMENTS Thanks are given to Mr. Fred W. Johnson of the Sagehen Creek Station staff, Avho assisted the writer in construction of the two spawn- ing beds described; and to graduate students Bob Behnke, John IIop- kirk, Don Roberts, Don Seegrist, and Ted Wooster, who assisted in resetting the observation tank late in the summer of 1959. T am also indebted to Dr. Peter Marler and to Dr. Richard Gard, who read the manuscript and offered suggestions for its improvement. SUMMARY (1) Spawning behavior of a single pair of eastern brook ti-out. Salvelinus fonthmlis, was studied in Sagehen Creek, California, from an underwater observation tank. (2) Two artificial spawning beds were constructed of gravel beside the two downstream windows of tlie tank. These proved most success- ful— the fish moving on to them promptly after they were installed. AVashed gravel of walnut size and smaller was used. (3) The pair observed was quite territorial, driving away all in- vaders aggressively from their nest area. No color changes were ob- served in the trout while assuming threat postures. (4) BroAvn trout, SaJmo trutta, stocked in the tank pool, spawned only at night, while the brook trout appeared to spawn both day and night. Rainbow trout, Salmo gairdnerii, did not moh^st the spawners at BROOK TROUT SPAWNING 39 any time, nor were they observed to attempt to eat eggs deposited in the redd. (5) Spawning activities of the female consisted of searching for a suitable nest site, nest cutting, testing of nest site by "anchoring" or "crouching," actually spawning, and covering eggs. During the latter process the female went through a kind of a "post-nuptial" dance in which she performed a weaving, undulating movement using the ven- tral portions of anal and caudal fins to gently push gravel into the pit over the eggs. After actually spawning once, she immediately began to cover the eggs. (6) The activities of the male were largely related to aggressively fighting off all intruders into the nest area and in sharing in the spawning act. He did not share in the cutting of the nest. (7) The female, when ready to spawn, produced an appropriate signal movement when her anal fin was in the deepest part of the pit. The male swiftly took his place beside her; both opened their mouths wide and trembled while eggs and milt were emitted simultaneously. About one second was required for each of the two acts observed. (8) The peak of the spawning period in Sagehen Creek occurred between October 1 and October 15 — when daily, minimum water tem- peratures ranged between 37 and 44 degrees F. Volume of water flow varied from 1.7 to 1.9 cubic feet per second over the same period. REFERENCES Bekling, David L. 1934. The spawning habits of the Atlantic salmon. Amer. Fish. Soe., Trans., vol. 64, pp. 211-218. Berry, John 1939. Account of hatching and stocking experiments. Avon Bio. Res., Ann. Rept., 1937-38, pp. 27-33. Briggs, John C. 1953. The behavior and reproduction of salmonid fishes in a small coastal stream. Calif. Dept. Fish and Game, Fish Bull. 94, 62 pp. Cramer, Frederick K. 1940. Notes on the natural spawning of cutthroat trout (Salmo clarkii clarkii) in Oregon. Sixth Pac. Sci. Cong., Proc, vol. 3, 1939, pp. 335-339. Fabricius, Eric 1950. Heterogeneous stimulus summation in the release of spawning activities in fish. Inst. Freshwater Res., Drottningholm, Rept. no. 31, 1949, pp. 57-99. 1953. Aquarium observations on the spawning behavior of the char, Salmo alpinus, L. Inst. Freshwater Res., Drottningholm, Rept. no. 34, 1952, pp. 14-48. Fabricius, Eric, and Karl-Jakob Gustafson 1954. Further aquarium observations on the spawning behavior of the char, Salmo alpinus L. Inst. Freshwater Res., Drottningholm, Rept. no. 35, 1953, pp. 58-104. Frost, Winnifred E. 1956. 24th Ann. Rept. of the Freshwater Biol. Assoc, (of the British Empire) for year ended 31 March, 1956, 65 pp. Greeley, John R. 1932. The spawning habits of the brook, brown, and rainbow trout and the prob- lem of egg predators. Amer. Fish. Soc, Trans., vol. 62, pp. 239-248. Hazzard, A. S. 1932. Some phases of the life history of the eastern brook trout, Salvelimis fonti- nalis Mitchell. Amer. Fish. Soc, Trans., vol. 62, pp. 344-350. 40 CALIFORNIA FISH AND GAME Ilohhs, Dorisley F. 19.S7. Xatm-al ri'in'odnction of qiiinnat saliiioii, hrowii ami raiiil)o\v trout in certain New Zealand waters. New Zealand Marine Dept., Fish r>nll. (5, 104 pp. Jones, J. "\V. !!)">!). The salmon. Collins, London, I'.KS pp. 19G0. Personal correspondence. .Tones, J. AV., and G. M. King 11)4!). Experimental observations on the spawning heiiavior of tiie Atlantic salmon (Salmo salar L. ), Zool. Soc. London, Proc, vol. 119, pp. 13-48. 19r>0. Further experimental observations on the spawning behavior of the Atlantic salmon (iSahiio salnr L. ) . Zool. Soc. London. Prof., vol. 120. pp. .S17-82.S. Jones, J. W., and J. N. Ball ]9r)4. The spawning behavior of lirown li-out and salniuii. I'.ril. .Juiir., .\ninial Behavior, vol. 2, pp. 103-114. Needham, P. R. lOnti. The Sagehen Creek exiicrinicnt.il wildlife and ti.sherics iirojecl. Anier. Inst. Biol. Sci, Bull., Nov. 1956, 3 p)). 19."9. New horizons in stocking liatclicr.v troiil. Trans. 24(li X. Amor. "Wildl. Couf., pp. 395-406. Needham, P. R., and A. C. Taft 1934. Observations on the S))awning of steelhcad front. Amer. Fish. Soc.. Trans., vol. 64, pp. 332-339. Needham. P. R., and Frank Sumner 1941. Fish management problems of high, western lakes with returns from marked trout planted in Upper Angora Lake, California. Amer. Fish. Soc, Trans., vol. 71, pp. 249-269. Needham, P. R., and T. M. Vaughn 1952. Spawning of the Dolly Varden in Twin Creek, Idaho. Copeia, no. 3, pp. 197-199. Ncedh.-im, P. R., and A. C. Jones 1959. Flow, temperature, solar radiation, and ice in relation to activities of fishes in Sagehen Creek, California. Ecology, vol. 40. no. .",. iij). 465-474. Schultz, Leonard P., and students 1935. The breeding activities of little redtish Onrorhynrhiis nerka, a land-locked form of the sockeye salmon. Jour. Pan. Pac. Res. Inst., vol. 10, no. 1, pp. 67-76. Smith, Osgood R. 1941. The spawning habits of cutthroat and eastern brook fronts. Jonr. Wildl. Mgt., vol. 5, no. 4, pp. 461-471. 1944. Returns from natural spawning of cutthroat trout and eastern brook trout. Amer. Fish. Soc, Trans., vol. 74, pp. 2S1-296. Stuart, T. A. 1953. Sjiawning migration, reproduction, and young stages of the loch trout (Salitio trutta L. ). Rept. No. 5, Freshwater and Salmon Fish. Res., Home Dept., Scotland, 39 pp. Tinbergen, N. 1951. The study of instinct. Oxfoi'd, I'niv. Press, 288 pp. CORRELATION OF FOOD HABITS AND ABUNDANCE OF WATERFOWL, HUMBOLDT BAY, CALIFORNIA' CHARLES F. YOCOM and MATHEW KELLER Division of Natural Resources, Humboldt State College Areata, California INTRODUCTION Humboldt Bay, located along the northwest coast of California in Iluniboldt County, is over 200 nautical miles north of San Francisco aiul approximately 180 nautical miles south of Coos Bay, Oregon. The width of Humboldt Bay varies from one-half to about four miles, and its length is approximately 14 miles. At high tide the water in the bay covers 24.5 square miles and at low tide 7.8 square miles. Two long narrow sand spits separate the north and south bays of Humboldt Bay from the ocean (Anonymous, 1955). Habitat types near the bay include coastal dunes on the west side, urban and agricultural on the north, east and south sides, and redwood forest type on the coastal mountains located immediately inland from the urban and agricultural areas (Yoconi and Dasmann, 1957). The agricultural lands are used primarily for dairy cattle pasture. Remnants of tide channels, now blocked off by dikes, occur in the pasture lands. These old channels fill with fresh water during the rainy season in early fall to late spring. They provide habitat for aquatic plants used by waterfowl. RELATIVE ABUNDANCE OF WATERFOWL An aerial inventory of the waterfowl in the Humboldt Bay area was taken by Bentley and Christianson (1957). Sixteen flights were made between October 16, 1956, and April 15, 1957. The highest concentra- tion was noted in January 1957, when over 50,000 birds were present. From this inventorj- and other field studies the authors calculated the average number of waterfowl by species for each month included in the study. Monthly averages of waterfowl species were totaled which indi- cated the relative abundance of each species for the entire period. These numbers were converted to percentages (Table 1). The seven most common waterfowl species utilizing Humboldt Bay were widgeon (Mareca americana), black brant (Branta nigricans), pintail {Anas acuta), canvasback {Aythya valisineria) , coot (Fuiica americana), lesser scaup {Aythya affinis) and greater scaup {Aythya ynarila). Lesser and greater scaup were treated as one group because of the difficulty of differentiation in the field. However, we estimated the wintering populations of greater scaup in Humboldt Bay to be larger than the lesser scaup populations. 1 Submitted for publication June, 1960. (41) 42 CALIFORNIA FISH AND GAME TABLE 1 Relative Abundance of Waterfowl from October 16, 1956-April 15, 1957, Humboldt Bay, California Species Percent of total Species Percent of total \\'ificoon ._ _ 47.1 20.2 15.6 4.2 2.7 2.5 .7 .6 .4 Mallard .3 Black brant -- _- Shoveler _ .3 Pintail - - Whistling swan .2 Scoter (.3 species) . .1 Coot Ruddy duck .1 Scaup (greater and lesser) Buffle-head - - -- Gadwall trace Canada goose trace Unidentified 4.8 Green- winged teal . The relative abundance figure for scoters, which includes white- winged scoter {Melanitia deglandi), surf scoter {Mela.nitki pcrspicil- lata) and an occasional American scoter (Oidemia nigra), apparently is low (Table 1). These birds were difficult to identify and count from an air})laiie or ground station because tlioy occur singly and in small groups dispersed over Humboldt Bay. FOOD HABITS STUDIED From 1953 to 1959 the authors compiled data on the food habits of Humboldt Bay waterfowl. Howard Leach, Califoi'nia DepartiiuMit of Fisli and Giame biologist, examined eight of the brant gizzards. Ivcjbert Talmadge, Willow Creek, aided in the identification of mollusks. A total of 393 gizzards of 11 species have been examined (Table A-1). Each plant item represents seeds unless otherwise indicated. The methods used in analyzing food contents in the duck stomachs were the same as those discussed by Yocom (1951). RELATIVE IMPORTANCE OF FOOD ITEMS In evaluating the importance of the food sources to the total water- fowl population feeding in the Humboldt Bay area, food habits have been correlated with the abundance of each species of waterfowl. The volume of each food item eaten was assumed to indicate the imjiortance of the item to the particular waterfowl species. To evaluate the im- portance of a specific food item to the total waterfowl population, wo considered the total number of waterfowl of all species consuming a specific item. For each species of waterfowl the values in the percent of total volume column were multiplied by a figure representing the relative abundance of that waterfowl species in the Humboldt Bay area. This procedure results in a "volume index." The volume rates for a food item for all waterfowl consuming it were added resulting in a figure representing an index of the importance of each food item to the total local waterfowl population (Table A-2). DISCUSSION Eelgrass (Zoafcra marina) is by far the most abundant waterfowl food plant in this area and is available to all Avaterfowl utilizing the WATERFOWL FOOD HABITS 43 open water of Humboldt Bay. Keller (1960) estimated 840 acres of eelgrass beds in the north and 2,015 acres in the south bays. Eelgrass was the principal food for widgeon {Mareca americana) and black brant (Bra7ita nigricans) whereas the other waterfowl ate it only occasion- ally. Brant were, for the most part, dependent on eelgrass for food (Cottam and Monro, 1954, and Cottam, 1941), but widgeons fed on several different green plant foods in different locations. Since widgeons in the Humboldt Bay area fed in fields and sloughs as well as on the bay, it appeared that their heavy utilization of eelgrass resulted from the availability and acceptability of the eelgrass rather than because of dependence upon it. The materials listed as "unidenti- fied vegetation ' ' under widgeon and brant in Table A-1 consisted prin- cipally of small fragments of eelgrass, clover, and grasses. Analyses of foods consumed showed that pintails ate plant foods commonly found in the shallow areas of the bay and in marshlands adjacent to it. Eelgrass was found in only one sample. Mallards (Anas platyrhynchos), which represented less than 0.5 per- cent of the wintering and migrating waterfowl populations, appar- ently obtained only a small portion of their food from the bay. The relatively small resident population and others that migrated to this area fed in the outlying ponds, marshes and streams where bulrushes (Scirpus spp.), spike rush (Eleocharis macrostachya), mare's tail (Hippuris vulgaris) and other species listed in Table A-1 were more abundant. AVhen disturbed by hunters, they use the bay or the open ocean as escape areas. Eelgrass was found in only two samples. In re- cent years many of the coastal marshes have been eliminated by dikes, earth fill and drainage thus reducing the number of mallards that nest and winter there. Green-winged teal (Anas caroUnensis) also used the marsh areas along old tide channels and coastal marshes near the bay for most of their food supply. Canvasbacks relied on animal food, pondweeds (Potamogeion spp.) and widgeon grass (Ruppia maritima). Eelgrass was found in only one specimen. Animal food from the bay was important in the diets of les- ser and greater scaups and buffleheads (Bucephala alheola). Eelgrass apparently was not an important food for these three species, because it was found only in two greater scaup. White-winged scoters ate primarily mollusks from the bay, whereas ruddy ducks (Oxynra jamaicensis) consumed primarily plant material of which widgeon grass was the most important. Barley (Hordenm vulgare) was taken in relatively large amounts by mallards and pintails although little is grown in the area. Some barley may have been obtained from baited hunting ponds. Creeping spike rush occurred frequently in green-winged teal, pintail, mallard, and widgeon stomachs, and in small amounts in ruddy and bnfflehead stom- achs. It should be noted that a food habits study indicates the food items consumed during the study, and not necessarily innate preferences of the waterfowl concerned. The food taken at any one time depends on both the preferences of the waterfowl and the availability of the food items. Thus as the availability of any food item changes, the food habits 4-4 CALIFORNIA FISH AXD CAMF. and pussihiy the r('lali\<' ahiiiKlaiicc of llic wali'rfowl iiia>' clianfje be- cause of iiioxcnient iiilo and away Iroiii an area. l*'or example, it seems likely that an increase in tlic a\ailaliilily ot' barley and other U'l'ains in tin's r(\uiay and else- where in the area were pi-oducing hai-\'es1ai)le ci'()i)s of mature oats (Avena sativa), barley and wheat (Tritinim (lestivum) which undoubt- edly furnished feed for the geese and grain-eating ducks. Under a grain-growing type of agriculture there would be a change in tlie per- centage of species of waterfowl wintering in this region. This study indicates that at the pi'esent time eelgrass is the most im- ])ortant single food item to the waterfowl that pass through and wanter in Humboldt TJay. From a numagenuMit standpoint there is probably little tluit can be done to increase the production of eelgrass in this bay, however, the present eelgrass beds should be protected from future damage. Excess siltation, pollution, or certain oyster culture practices could reduce greatlv the amonnt of eelgrass available to waterfowl (Keller, 1960). SUMMARY In order to determine the relative importance of various food items to the total waterfowl ])opulation of the Humboldt Bay area, food habits aiul abundance of each species of waterfowl were correlated. Eelgrass, unidentified vegetation, clams, barley, clover, creeping spike rush. ]U-airie bulrush, and widgeon grass, in order of importance, ac- counted for !)4.() ])ercent of the volume indices. This indicated that at the present time eelgrass is the most important waterfowl food item in the Humboldt Bay area. LITERATURE CITED Anonymous lOSf). Humboldt Bay, California. A literature survey. T'niversity of Washington Department of Oceanography. 144 pp. Bentley, W. W. and E. R. Christianson 1957. A coiHiiiuous aerial inveiit(U-y of waterfowl in tlie TlumlioUlt l>ay area. Unpulilished report, Ilunilioldt State College. Cottam, Clarence and David A. Monro 1954. Eelgrass status and en\irinun('nt,il relations. .Innr. Wildl. Mgt. \d]. IS, no 4, i)p. 449-4G0. Keller, Mathew ]9(;0. The distriltntion and importance of eelgrass (Zosfrra marina) in ITumholdt liay. California. I'liiiuhlished blaster's thesis, IIuml)oldt State C(dlege, Ar- eata, California. ^Nloffitt, .Tames and Clarence Cottam 1941. lOelgrass depletion on the Pacific coast and its effect on tlie lilack hr.int. U.S. Dept. of the Int.. V. and W. S., Wildl. L.^atlet L'dl. liC, p].. Yocom, Charles F. 1951. AYaterfowl and their food plants in Wa.shington. University of Washington Press, Seattle. 272 pp. Yocom, Charles and Raymond Dasmann 1957. The Pacific coastal wildlife region. Nalurcgraph Co., San Martin, Cali- foi'uia. 112 IP)). WATERFOWL FOOD HABITS 45 APPENDIX TABLE A-1 Food of Eleven Species of Waterfowl, Humboldt Bay, California Food items PINTAIL (49) 15.6% of population PLANT FOOD Hordeum vulgare Barley Scirpus paludosus Prairie Bulrush Eleocharis macrostachya Creeping Spike Rush Ruppia maritima Widgeon Grass Distichlis spicata Salt Grass Rosa sp. Rose Zostera marina (vegetation) Eelgrass Plantago sp. Plantain Sparganium eurycarpum Broad-Fruited Bur Reed. Scirpus americanus Three Square Potamogeton sp. Pondweed Sparganium sp. Bur Reed Polygonum persicaria Lady's-thumb Potamogeton pectinatus Sago Pondweed Melrlotus sp. Sweet Clover Galium sp ('arex ohnupta Slough Sedge Scirpus sp. Bulrush Polygonum sp. Sniartweed Rumex sp. Dock Ranunculus sp. Buttercup Cornus sp. Dogwood Hippuris vulgaris Mare's Tail Unidentified Vegetation ANIMAL FOOD Unidentified Pelecypoda Clams Unidentified Gastropoda Gastropods Unidentified MoUusca Mollusks Unidentified Arthropoda Arthropod Total Frequency 10 16 24 5 3 3 1 1 1 2 10 3 3 2 2 2 23 12 4 1 1 Percent of frequency 20.4 32.6 49.0 10.2 6.1 6.1 2.0 2.0 2.0 4.1 20.4 6.1 6.1 4.1 4.1 4.1 2.0 2.0 2.0 2.0 2.0 2.0 2.0 46.9 24.. 5 8.2 2.0 2.0 Frequency rate 318.2 .508.6 764.4 159.1 95.2 95.2 31.2 31.2 31.2 64.0 318.2 95.2 95.2 64.0 64.0 64.0 31.2 31.2 31.2 31.2 31.2 31.2 31.2 731.6 382.2 127.9 31.2 31.2 Volume 12.4 7.3 2.4 2.3 .4 .2 .2 .1 .1 .1 ♦trace trace trace trace trace trace trace trace trace trace trace trace trace 17.0 5.5 .7 .4 trace 42.9 Percent of total volume 25.2 14.8 4.8 4.7 .8 .4 .4 .2 .2 .1 .1 trace trace trace trace trace trace trace trace trace trace trace trace 34.7 11.2 1.3 .8 trace 98.7 Volume rate 392.4 230.7 75.1 73.2 13.0 6.7 6.3 3.2 3.2 1.7 1.6 .5 .5 .3 .3 .3 .2 .2 .2 .2 .2 .2 2 541.4 175.7 20.7 12.7 .2 46 CALIFORNIA FISH AND GAME TABLE A-1— Continued Food of Eleven Species of Waterfowl, Humboldt Bay, California Food items MALLARD (24) 0.3% of population PLANT FOOD Hordeum vulgare Barley Potamogeton sp. Pondweed Eleocharis macrostachya Creepinc Spike Rush Scirpus paludosus Prairie Bulrush Carex obnupta Slough Sedge Zostera marina (vegetation) Eelgrass Hippuris vulgaris Mare's TaiL._ .-. Polygonum sp. Smartweed Rantinculus flabellaris Yellow Water Crowfoot.. Polygonum persicaria Lady's thumb Scirpus americanus Three Square Sparganium sp. Bur Reed Potamogeton pectinatus Sago Pondweed Anacharis sp. Waterweed Potamogeton natans Floating-Leaf Pondweed. . Zostera marina (seeds) Eelgrass Alopecurus sp. Foxtail Gramineae Unknown grass Polygonum natans Water persicaria Polygonum punclatum Dotted Smartweed Polygonum lapalhifolium Pale persicaria Polygonum, coccineum Swamp Knotweed Rumex sp. Dock Ranunculus sp. Buttercup Amarantlius sp. Amaranth Cirsium sp. Thistle Cornua sp. Dogwood Frequency Unidentified vegetation . 7 11 14 4 1 2 5 4 1 3 1 3 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 6 Percent of frequency 29.2 4.5.8 58.3 16.7 4.2 8.3 20.8 16.7 4.2 12.. 5 4.2 12.5 8.3 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 25.0 Frequency rate 8.8 13.7 17.5 5.0 1.3 2.5 6.2 5.0 1.3 3.8 1.3 3.8 2.5 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 7.5 Volume 5.6 1.6 .6 .4 .3 .3 .3 .2 .2 .2 2 .2 .1 trace trace trace trace trace trace trace trace trace trace trace trace trace trace .7 Percent of total volume 49.6 13.9 5.8 3.9 2.7 2.2 2.2 1.8 1.8 1.3 1.3 1.3 .9 .6 .4 trace trace trace trace trace trace trace trace trace trace trace trace 6.0 Volume rate 14.9 4.2 1.7 1.2 .8 .7 .7 .5 .5 .4 .4 .4 .3 .2 .1 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 1.8 WATERFOWL FOOD HABITS 47 TABLE A-1— Continued Food of Eleven Species of Waterfowl, Humboldt Bay, California Food items Frequency Percent of frequency Frequency rate Volume Percent of total volume Volume rate MALLARD (24)— Continued ANIMAL FOOD Insects Unidentified Insect Pelecypoda Unidentified clams Gastropoda Unidentified gastropods Total. GREEN- WINGED TEAL (50) .4% of population PLANT FOOD Eleocharis macrostachya Creeping Spike Rush Ranunculus sp. Buttercup Scirpus paludosus Prairie Bulrush Triticum sp. Wheat Alopecurus sp. Foxtail Potamogeton pectinatus Sago pondweed Polygonum lapathifolium Pale persicaria Distichlis spicata Salt grass Ruppia maritima Widgeon Grass Carex obnupta Slough Sedge Chenopodium sp. Goosef oot Carex sp. Sedge Sparganium sp. Bur Reed Scirpus validus American Great Bulrush- Polygonum persicaria Lady's Thumb Polygonum hydropiper Water Pepper Juncus sp. Rush Melilotus sp. Sweet Clover Hippuris vulgaris Mare's Tail Unidentified Seed LTnidentified Vegetation ANIMAL FOOD Gastropoda Unidentified gastropods- - MoUusca Unidentified moUusks Unidentified animal matter. Total 26 5 19 2 3 3 1 6 6 5 2 2 2 1 1 1 1 1 1 1 12 16.7 8.3 4.2 52.0 10.0 38.0 4.0 6.0 6.0 2.0 12.0 12.0 10.0 4.0 4.0 4.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 24.0 0.0 10.0 2.0 5.0 2.5 1.3 20.8 4.0 15.2 1.6 2.4 2.4 .8 4.8 4.8 4.0 1.6 1.6 1.6 .8 .8 .8 .8 .8 .8 .8 9.6 2.4 4.0 .8 .2 .1 .1 11.3 1.5 .8 .7 .5 .4 .2 .2 trace trace trace trace trace trace trace trace trace trace trace trace trace 1.8 3.2 trace trace 9.3 1.5 .9 .9 99.3 15.0 8.5 7.6 5.2 4.3 2.4 2.1 .3 .3 .3 .1 .1 .1 trace trace trace trace trace trace trace 18.9 33.6 .3 .5 99.5 6.0 3.4 3.0 2.1 1.7 1.0 .8 .1 .1 1.0 .04 .04 .04 .02 .02 .02 .02 .02 .02 .02 7.0 13.4 .1 .2 48 CALIFORNIA FISTI AND nA:\IE TABLE A-l— Continued Food of Eleven Spec'es of Waterfowl. Humboldt Bav, California j 1 Percent of Percent of Fre(|uency total Volume r.....! itrni- Freauency frequency rate Volume volume rate BALDPATE fl40) 47.1% of poiMilation PLANT FOOD Zoalrrn marina (VeRetation) Eclcrass^ IL'I 86 . 1 4.069.4 120.0 81.0 3,816.8 TriHium sp. (Vegetation) Clover 9 (\.i .301.4 P.O 6.0 282.7 Elcnc.hnris mncroRtnrhva Creepine Spiko Rush ?0 27.0 1,314.1 5.2 3.5 1 f, 1 . 1 Ninvurifs mJanrif: Mare's Tail,. 5 3.6 169.6 1.5 1.2 48.3 Mflilotux sp. Sweet Clover 2 1.4 65.9 1.2 .8 38.2 Spnroaniuw sp. Bur Reed 2 1.4 65.9 .6 .4 10.2 Potamoprlnn vertinatus Saeo Pondweed .5 3.6 169.6 .5 .3 14.6 Pnhignnum SD. Smartweed 1 .7 .33.0 . t .3 12.7 Pnlnmnqrtnn sp. Pondweed 4 4.3 2.9 202 . 5 136.6 .2 .2 .1 8.8 Unidentified Grass blades 5.09 S"irvus pahidnsvs Prairie Bulrush 6 4.3 202.5 trace trace .9 DiMirhlix spicatn Salt Grass 3 2.1 98.9 trace trace .5 Scirpus acntiis Viscid Bulrush 2 1.4 65.9 trace trace .3 Ranunculus sp. Buttercup 2 1.4 65.9 trace trace .3 Pnhiqnnnm versicari'i Lady's Thumb 1 .7 33.0 trace trace .1 Rumex sp. Dock 1 .7 33.0 trace trace .1 Amaranthvif sp. .\maranth - 1 .7 .33.0 trace trace .1 Plnntaqn sp. Plantain 1 2 .7 1.4 33.0 65.9 trace trace trace trace .1 Unidentified Seed .3 Moss Unidentified 1 45 .7 32.1 ^3.0 1,511.9 trace 8.8 trace 5.9 .1 Unidentified Vegetation 279.6 ANIMAL FOOD Insect a Unidentified Insect 4 2.9 136.6 .5 .3 16.4 Gastroijoda Unidentified Gastropod 1 .7 33.0 trace trace .1 Unidentified Animal Matter 1 .7 33.0 trace trace .1 Total 148.1 100.0 CANVASBACK fl7) 4.2% of population PLANT FOOD Potnmonrton pectinntun SaKO Pondweed 7 41.2 173.0 4.2 15.7 65.8 H unpin mariiimn Widgeon Grass 3 17.6 73.9 .7 2.6 1 1 .0 Potamoffrlon s|i. Pondweefl . _ 1 5.9 24.8 trace trace .08 Znslrrn mtirina J'-elKruBs , 1 5 . 9 24.8 trace trace .08 WATERFOWL FOOD HABITS 49 TABLE A-1— Continued Food of Eleven Species of Waterfowl, Humboldt Bay, California Food items CANVASBACK (17)— Continued ANIMAL FOOD Pelecypoda Unidentified Clams Macoma sp. (Clam) TotaL LESSER SCAUP (13) .3% of population PLANT FOOD Triticum sp. Wheat Potamogeton sp. Pondweed Potamogeton pectinatus Sago Pondweed Eleocharis macrostachya Creeping Spike Rush Distichlis spicata Salt Grass Scirpus paludosus Prairie Bulrush Hippusus vulgaris Mare's Tail Sparganium sp. Bur Reed Sparganium eurycarpum Broad Fruited Bur Reed_ Ruppia maritima Widgeon Grass Scirpus aciitus Viscid Bulrush Polygonum persicaria Lady's Thumb Ra n u nc ul us fla bella ris Yellow Water Crowfoot-. Unidentified Seed Unidentified Vegetation ANIMAL FOOD Macoma sp. Clam MoUusca Unidentified MoUusk Crustacea LTnidentified Crustacian. Gastropoda Unidentified Gastropod _ Total GREATER SCAUP (20) 2..3','c of i)opulation PLANT FOOD Zostera -marina Eelgrass Scirpus paludosus Prairie Bulrush Percent of Frequency frequency ANIMAL FOOD Colunibella carinata Gastropod 11 1 64.7 5.9 7.7 23.1 15.4 23.1 15.4 15.4 15.4 7.7 7.7 7.7 7.7 7.7 7.7 7.7 38.5 7.7 7.7 15.4 7.7 Frequency rate 10.0 5.0 35.0 271.7 24.8 2.3 6.9 4.6 6.9 4.6 4.6 4.6 2.3 2.3 2.3 2.3 2.3 2.3 2.3 11.6 2.3 2.3 4.6 2.3 Volume 23.0 11.5 80.5 18.9 3.0 26.8 Percent of total volume .5 .1 trace trace trace trace trace trace trace trace trace trace trace trace 3.09 5.0 1.0 .5 trace 10.1 .6 trace 4.9 70.5 11.2 100.0 4.6 .5 .2 .1 .1 .1 .1 trace trace trace trace trace trace trace 34.7 45.5 9.1 4.6 trace 99.6 4.4 trace 35.7 Volume rate 296.08 47.0 1.4 .2 .05 .04 .03 .03 .03 .01 .01 .01 .01 .01 .01 .01 10.4 13.7 2.7 1.4 .03 10.2 .2 82.1 .')() CALIFORNIA FISTT AXD CiAME TABLE A-1— Continued Food of Eleven Species of Waterfowl, Humboldt Bay, California Food itoins GREATER SCAUP (20) Continued Pelecypoda Unidentified Clams Nassarius tnendicus Gastropod Macoma sp. Clam Colli mbella aurantiaca Gastropod MoUusca Unidentified Mollusk A'ossariiis fossalus Gastropod NaKsarius sp. Gastropod Lacuna sp. Gastropod Total BUFFLEHEAD (22) .7% of population PLANT FOOD Scirpus paludosus Prairie Bulrush Ruppia maritima Widgeon Grass Pdtamogeton pectinatus Sago Pond weed Potamogeton pectinatus Sago Pondweed Tubers. . Hippurus vulgaris Mare's Tail Potamogeton sp. Pondweed Circium sp. Thistle Sparganium sp. Bur Reed Sparganium eurycarpum Broad Fruited Bur Reed. Trifolium sp. Clover Rosa sp. Rose Eleocharis macrostachya Creeping Spike Rush Unidentified Vegetation ANIMAL FOOD Hemiptera Unidentified Bug Pelecypoda Unidentified Clams Crustacea Unidentified Crab Crustacea Unidentified Shrimp Lacuna sp. f jastropod Gastropoda Unidentified Gastropod.. Frciiucncy 10 .3 3 2 1 1 1 1 Percent of frequency 50.0 \r,.o 1.5.0 10.0 5.0 5.0 5.0 5.0 18.2 22.7 13.6 4.5 9.1 9.1 9.1 9.1 4.5 4.5 4.5 4.5 4.5 18.2 31.8 22.7 18.2 13.6 18.2 Frequency rate 11."). 0 34.5 .34.5 23.0 11.5 11.5 11.5 11.5 12.7 15.9 9.5 3.2 6.4 6.4 6.4 6.4 3.2 3.2 3.2 3.2 3.2 12.7 22.3 15.9 12.7 9.5 12.7 Volume 3.9 .8 1.9 .7 .4 .4 trace trace 13.6 .3 .1 .1 .1 trace trace trace trace trace trace trace trace trace 1.6 1.1 1.0 .9 .6 Percent of total volume 28.8 5.9 14.0 5.2 2.9 2.9 trace trace 99.8 5.1 1.9 1.8 1.6 .2 .2 .2 .2 trace trace trace trace trace 25.7 17.5 15.3 14.5 9.6 3.5 Volume rate WATERFOWL FOOD HABITS 51 TABLE A-1— Continued Food of Eleven Species of Waterfowl, Humboldt Bay, California Food items Frequency Percent of frequency Frequency rate Volume Percent of total volume Volume rate BUFFLEHEAD (22)— Continued Odestomia sp. Gastropod Columbella aurantiaca Gastropod Columbella guspata Gastropod Total- WHITE- WINGED SCOTER (17) .1% of population PLANT FOOD Ulva sp. Sea Lettuce ANIMAL FOOD Pelecypoda Unidentified Clams - Nassarius mendicus Gastropod Ostra sp. Oyster Crustacea Unidentified Crab._ Cohimbella aurantiaca Gastropod Columbella carinata Gastropod Olivella biplicata Olive Shell Olivella pedroana Gastropod Columbella gauspata Gastropod Nassarius fassatus Gastropod Nassarius cooperi Gastropod Littorina sp. Periwinkle Total- RUDDY DUCK (21) ,1% of population PLANT FOOD Ruppia maritima Widgeon Grass Potamogeton pectinatus Sago Pondweed Potamogeton sp. Pondweed Potamogeton pectinatus Sago Pondweed tubers. Scirpus paludosus Prairie Bulrush Eleocharis macrostachya Creeping Spike Rush__ Zostera marina Eelgrass 15 8 1 4 2 7 2 4.5 4.5 4.5 5.9 88.2 47.1 5.9 23.5 11.8 41.2 11.8 5.9 5.9 5.9 5.9 5.9 13 61.9 16 76.3 2 9.5 1 4.8 3 14.3 4 19.0 1 4.8 3.2 3.2 3.2 .6 8.9 4.7 .6 2.4 1.2 4.1 1.2 .6 .6 .6 .6 .6 6.2 7.6 .9 .5 1.4 1.9 .5 .1 trace trace 6.1 trace 5.7 4.6 2.2 1.5 1.2 1.0 .5 .1 trace trace trace trace 17.7 1.6 .8 trace 99.7 trace 48.8 17.4 14.1 6.6 4.6 3.6 2.9 1.5 .3 trace trace trace 99.8 6.2 68.1 6.8 1.6 17.4 1.7 .3 3.3 .3 .2 1.6 .2 .1 1.2 .1 .1 1.4 .1 .1 2.0 .1 1.1 .6 .05 .001 4.9 1.7 1.4 .7 .5 .4 .3 .2 .03 .001 .001 .001 52 CALIFORNIA FISH AND GAME TABLE A-1— Continued Food of Eleven Species of Waterfowl, Humboldt Bay, California Food items Frequency Percent of frequency Frequency rate Volume Percent of total volume Volume rate RUDDY DUCK (21i - Continued Hippurus vtdgaris Mare's Tail 2 1 1 1 2 9.5 4.8 4.8 4.8 9.5 1.0 .5 .5 .5 1.0 trace trace trace trace .5 .1 trace trace trace 5.5 .01 Scirpus americanua Three Square .005 Ranunculus sp. Buttercup .. _- .005 Circium sp. Thistle 005 ANIMAL FOOD Crustacea Unidentified sliriinp _ .6 Total . -. - 16 12 1 2 2 1 80.0 60.0 5.0 10.0 10.0 5.0 1,616.0 1,212.0 101.0 202.0 202.0 101.0 9.1 18.2 4.1 trace trace trace trace 100.6 81.3 18.5 trace trace trace trace BLACK BRANT (20) 20.2' e of po|)ulation PLANT FOOD Zostera marina Eelgrass Unidentified Vegetation Salicornia ambigua Pickleweed 1,643.129 373.700 .444 Diatoms ANIMAL FOOD Crustacea Unidentified Crustacea Gastropoda Egg cases. . .909 1.353 .444 Total.. 22.3 99.8 * Values carried to three decimal places were used in calculating the frequency and volume rates. WATERFOWL FOOD HABITS 53 TABLE A-2 * Summation of Volume Indices Food items Percent of volume rates Zostera marina Eelgrass Unidentified Vegetation Pelecypoda Unidentified Clams Hordeum vulgare Barley TrifoUum sp. (vegetation) Clover Eleocharis macrostachya Creeping Spike Rush Scirpus paludosus Prairie Bulrush Ruppia maritima Widgeon Grass Potamogeton pectinatus Sago Pondweed Macoma sp Clam Hippuris vulgaris Mare's Tail Melilotus sp Sweet Clover Gastropoda Unidentified Gastropods Sparganium sp Bur Reed Hemiptera Unknown Bug Mollusca Unknown MoUusk Nassarius mendicus Gastropod Potamogeton sp Pondweed Distichlis spicata Salt Grass Polygonum sp Smartweed Columbella aurentiaca Gastropod Crustacea Shrimp Lacuna sp Gastropod Nassarius fossattis Gastropod Rosa sp Rose Graminae Unidentified Grass vegetation Ranunculus sp Buttercup Triticum sp Wheat Crustacea Unidentified Sparganium eurycarpum Broad Fruited Bur Reed Scirpus americanus Three-square Alopecurus sp Foxtail Ostra sp Oyster Polygonum persicaria Lady's Thumb 60.9 13.5 6.1 4.5 3.1 2.7 1.0 1.0 .9 .4 .2 .04 .04 .03 .02 .02 .02 .02 .01 Food items Percent of volume rates Carex obnupta .01 Slough Sedge Potamogeton pectinatus .01 Sago Pondweed Tubers Scirpus sp trace Bulrush Rumex sp trace Dock Cornus sp trace Dogwood Galium sp trace Galium Ranunculus flabellaris- trace Yellow Water Crowfoot Polygonum lapathifolium trace Pale Persicaria Anacharis sp .2 Waterweed Potamogeton natans .2 Floating Leaf Pondweed Zostera marina (seed) .2 Eelgrass Gramineae .2 Unidentified Grass Polygonum punetatum .2 Dotted Smartweed Polygonum coccineum .2 Swamp Knotweed Amaranthus sp .2 Amaranth Circium sp .2 Thistle Chenopodium sp .2 Goosefoot Carex sp trace Sedge Scirpus validus trace American Great Bulrush Polygonum hydropiper trace Water Pepper Juncus sp trace Rush Scirpus acutus .4 Viscid Bulrush Potamogeton pectinatus .4 Tubers (Sago Pondweed) Salicornia ambigua .6 vegetation (Pickleweed) Diatoms 1.1 Moss .2 Ulva sp .2 Sea Lettuce Littorina sp .2 Periwinkle Arthropoda .2 Unidentified Arthropod Unidentified Animal Matter .2 Nassarius sp .1 Gastropod Columbella guspata .02 Gastropod Columbella carniata .03 Olivella biplicata .03 OUve Shell Olivella pedroana .03 Gastropod Nassarius cooperi .03 Gastropod * Food items in the table arranged in order of frequency of occurrence. KING SALMON SPAWNING STOCKS OF THE CALIFORNIA CENTRAL VALLEY, 1940-1959' DONALD H. FRY, JR. Marine Resources Branch California Department of Fish nad Gome INTRODUCTION This paper lists the best available counts and estimates of the king- salmon Oncorlujnclius tshmvytscha (Walbaiim) spawning runs of the Sacramento-San Joaquin River system from 1940 to 1959. The first serious effort to determine the size of salmon runs in the Central Valley came as a result of the proposed construction of Shasta Dam. Part of the information needed to evaluate the effects of this proposed project on the fisheries was a count of the salmon which would be blocked. The first count was made in 1937, and every year since then a count or estimate has been made in one or more Central Valley streams. Estimates of the total fall run in all Central Valley streams did not start until much later. Almost all the counts given in the accompanying tables were made by the California Department of Fish and Game or the U. S. Fish and Wildlife Service. The only exceptions are the 1940-41 counts in the Sacramento River which were made by the U. S. Bureau of Reclamation. Many counts and estimates were incomplete because counting had to be done at places where high water made it possible for fish to pass by uncounted, because fish counting weirs could not be kept fish tight, and because of the difficulty in seeing enough fish to make a satisfactory estimate possible in some of the larger streams. In addition, most of the earlier counts were made by men who had done little or no work with salmon. These men learned as they worked, but at first they did not fully appreciate how many salmon will go through a small hole in a counting weir, or how small a percent of the fish can actually be seen even in a stream where visibility seems excellent. This inevitably led to esti- mates which were too low — sometimes ridiculously low. In general the larger the stream the worse the difficulties of this type. For such rea- sons, during the 1940 's, some of the estimates on the tributary streams and all of the totals on the main stem of the Sacramento were probably much too low. By way of contrast : On the tributaries the actual counts (other than incomplete counts) are reasonably accurate whenever and wherever listed, but are minimal rather than maximal. Counting of salmon is relatively simple only where the entire spawn- ing run can be forced to pass through a counting gate such as can be 1 Submitted for publication May, 1960. Map by Cliffa Corson. (55) .•")(] f'ALlFORNlA FISH AND GAME ''•*<•. A (? SALMON STREAMS KyM. OF THE CENTRAL VALLEY OF CALIFORNIA ^ LEGEND 2 / r <(° ^ I IMPASSABLE DAM Y ^ D 0AM OR RACK USED ) ^Y FOR SALMON COUNTING oHATCHERY f V 0 10 20 30 mi. Scale of Miles ^ \ ^ '4 5 0^ N r^NV / ^' -r\- ■janXf .•^i \/- SACRAMENTO|i^ ^iM^^^ > ^ /co' \ J) , Y ^oo<^ \ /S/v ^oo^;:!!l^«,v^'' TV .v-x /ML Xv C^ =^^&-g^^^ ^STOCKTON * SAN ^N^" 7 i .l5UA^i>C FRANCISCO ^S. \ ^Tuolumne P' S^ ^ ] Sb ^ o o \ ^^ OOSPALOS* V"*© i^^f SCO. 00 A ^^^^vy^ J Mendoto Dom^ FRESNO^ ^ \ FIGURE 1. Salmon streams of the Central Valley. Only those streams and counting stations mentioned in the text are shown here. Dams with fishways are shown if mentioned in the text. SALMON SPAWNING STOCKS 57 placed in a fish way over an otherwise impassable barrier. In the Central Valley no major run can be counted this easily. For want of better places, much counting has been done at dams which have spawning area below them. Such counts are incomplete and must be supplemented with an estimate of the tish spawning- down- stream from the dam if a true idea of the entire spawning run is to be obtained. Often no satisfactory estimate could be made. A good many of the earlier counts were made by the use of fish counting weirs or racks. These are structures which strain the water of the stream while, in theory, permitting the fish to go upstream only through counting gates. The more expensive ones used parallel lengths of pipe set close enough together to block the salmon, somewhat cheaper ones were wooden, and the cheapest of all were constructed of wire mesh. None proved satisfactory. Floods topped them or scoured holes underneath them, or the fish found or made small openings which they used in preference to the counting gates. One counter at such a place gave up trying to mend all the holes, closed down his counting gate, and counted the fisli through the opening they seemed to like best. Some of the runs have been calculated by the use of tag and recov- ery methods. For this type of study fish should be caught and tagged near the downstream end of a spawning area, then released and al- lowed to spawn naturally. After the fish have spawned and died the ratio of tagged to untagged fish is determined. To use a simplified example : If 500 tagged fish have been released in the stream and one out of ten spawned-out carcasses is tagged, it is assumed that the run is approximately 5,000 fish. This method has worked cpiite satisfactorily on the American and Stanislaus Rivers. It has proven much less satis- factory on the main stem of the Sacramento,- but nonetheless it has been the best available source of information on the main stream for several years. The tag and recovery method has ]n^oven quite valuable as a method of training personnel to estimate the size of the run in a stream. After a man has learned from a tagging experiment about what proportion of the fish he can expect to see under certain conditions, he is then much better able to estimate the size of a run in a stream where no tagging has been done. Most of the Department of Fish and Game estimates were made by counting spawned-out carcasses and esti- mating the percent which the crew could be expected to find. Another method of estimating involves aerial redd (nest) counts. There are difficulties such as those caused by many fish spawning so close together that the nests cannot be separated, but in streams where the bottom can be clearly seen the method should have good possi- bilities. Unfortunately, it has not yet been possible to check aerial redd counts against a fish ladder count. Occasionally more than one estimate has appeared for a single stream for one year. One reason for this was that the Department of - There are several reasons why tag and recovery methods have not yet been made satisfactory on the main stem of tlie Sacramento. Probably the most important has been the difficulty of recovering adequate numbers of spawned-out tagged carcasses in the main stem because of deep and murky water ; the tagging site was only a few miles above the mouth of the Feather and was too far down- stream ; and the cylindrical wire traps used for catching tlie fish selected much too high a proportion of small salmon, 58 CALIFORNIA FISH AND GAME Fisli Jiiul Came and tlio TT.S. Fish and Wildlife Service sometimes made separate estimates. I^>oth or.")() estimates were made of the Dcci- Creek run. Apparently the natural spring run was not increased by the addition of transfers from Keswick. No weir counts were made of the fall i-un. The U.S. Fish and Wildlife Service estimated the size of the fall run from 1947 through lil.jij. The fall run estimates during the next three years were joint ventures involving both Federal and State nieii. Since that time esti- mates of the fall run (but not tlie spring run) have been made by the Department of Fish and Game. Since 3947 the largest fall run was 12,000 fish in 1952, and there were five years when the run dropped below 500. The highest spring run on record was 4,000 in 1946; in 1940 it was below 500. Chico Creek The fall run of Chico Creek was estimated as 50 fish in 1!»57, and the spring run as 1,000 in 1958 and 200 in 1959. It appears that no other estimates have been made. The 1957 fall run w^as included under "Miscellaneous Small Streams." An additional 15 miles of spawning area was opened on Chico Creek during the summer of 1958 by the re- moval of a barrier. Butte Creek Butte Creek, unlike the majority of the small streams of the northern Sacramento Valle.v, has a spring run but almost no fall run. There are numerous removable dams on Butte Creek which are left in place so late that the fall run has little chance to get past them. Some of these diversions are for duck clubs. Fishways have improved conditions somewhat, but the fall run has not built up. The spring run has ranged from 3,000 fisli in 1956 down to less than 500 in 1953 and 1959. Miscellaneous Small Tributaries of the Upper Sacramento River Included under this heading are Antelope Creek. Clear Creek, Cot- tonwood Creek, Cow Creek, Paynes Creek, and about a dozen other streams which may have fall runs when the fall rains are early and heavy. Some of the streams have spring runs. The fall runs were esti- mated by the U.S. Fish and Wildlife Service from 1947 through 1953, by a joint venture through 1956, and since that time by the Department of Fish and Game. The survey of these minor streams is moi-(> comjilete now^ than it was in former years. Since 1947 the largest fall run in all of these streams combined was 13,000 fish in 1953. It was down to l.OOO in 1948 and 1949. The spring run totals in the only three years of recoi'd wei'c under 500 fish twice, and once (1956) reached 1,000 fish. SALMON SPAWNING STOCKS 63 Feather River The Feather River is the largest tributary of the Sacramento below Shasta Dam. Dams and diversions have worsened conditions for the salmon — especially the spring run. In spite of this the Feather is still a good salmon stream. There are runs which spawn in the main stream, the North Fork, the West Branch of the North Fork, the Middle Fork, and the South Fork. The majority of the 'fish enter in the fall; the largest part of this run spawns in the main stream. The majority of the spring run fish spawn in the Middle Fork, with a few in the North Fork, South Fork, and West Branch. The U.S. Fish and AVilcllife Service made an estimate of the sjDring and fall runs in 1946. The men who did the work were not experienced at making estimates on the spawning grounds, and after considering their counts of spawning and dead fish it is the belief of the depart- ment that this estimate represents only a small part of the fish that entered the Feather that year. Since 1953 the Department of Fish and Game has estimated the size of the fall run from spawning area surveys. In 1958 and 1959 this was supplemented with aerial redd counts. The spring run was also estimated in 1958 and 1959. The highest fall run was 86,000 in 1955. The low year was 1957 with 10,000 fish. Estimates of the spring run have ranged from 4,000 in 1959 down to 1,000 in 1955 and 1957. Yuba River For many years the Yuba River was seriously handicapped by a diversion dam below which there was often very little water and over which there was no functional fish ladder. Upstream migrants could pass only during very high flows. There are now two good fish ladders, one at each end of this dam, but the water problem still remains. The fall runs in the Yuba have been estimated by the Department of Fish and Game since 1953. They ranged from a high of 10,000 in 1959 to a low of 1,000 in 1957. The Yuba is known to have had a spring run but no estimate of its size has been made. This run has virtually disappeared. American River The American River formerly had a partial block at the old Folsom power dam over which' there was a fishway. More recently it has been totally blocked by a dam at Nimbus. Spawning grounds below Folsom were quite extensive, but the new Nimbus Dam has cut oif the grounds which were formerly used by over two-thirds of the fish. The new Folsom Dam has created some temperature problems which adversely affect the Nimbus salmon hatchery and the salmon spawning naturally in the River below. Counts were made by the Department of Fish and Game of the runs into the American River in 1941 and 1942, but due to early floods these counts were so incomplete that they have not been included in the tables. Tagging experiments were conducted from 1943 through 1946. The 1943 experiment was not completed and results were not included in the tables. From 1948 on, estimates of the size of the American River run have been made by the department. The one exception was in 1950 when an early flood made an estimate impossible. Since 1955 (J4 CALIFORNIA FISH AND GAME fish taken al llic i-cei'iilly L-uiislnictetl Xiiiibiis liaU-iiery arc; also iu- cliiilcd ill tlic 1al)l('s. At least through ]!)")] tliere was a small spring niii ill tlic Aiiicrii-aii. hut at sjiawning tiiiic these fish became so mixed with those of the niiieh larger fall run tliat it was impossil)le to separate tht'in. The highest total run recorded on the American Kiver was 39,000 in 1!)45. The lowest was 6,000 in .1956. Cosumnes River J 'arts of tlie Cosumnes Ki\er often have little or no llowing water until late fall or winter. Nature is responsible for most of this diffi- culty, but man contributes. This stream has a late fall run and no spring run. A ])artial count was made by the Department of i'Msh and (iame in 194]. Estimates were made by the department in 1953, and during each year since then. The highest estimate was '},{)()() in 19r)4. Tlic hiwest was below 500 in IKf)!). Mokelumne River The .Mokelumne Kiver salmon runs have been greatly reduced by man's activities. Uelow Wootlbridge Dam there is often too little water for the passage of salmon; for many years the dam itself was a serious fish block; industrial and mining pollution have, at times, been very serious. Tlie stream has a fall run, but the si)ring run appears to be pi-act ically extinct. All counts were made by the Department of Fish and Game, and all were made at Woodbridge Dam, which is located below all spawning areas. Partial counts w-ere made in 1940, 1941, and 1942; c(miplete counts in most of the following years. Woodbridge Dam has removable flashboards, but a good count can be made there in most seasons. In both 1941 and 1942, incomplete counts gave 12,000 fish. In no other year have the counts — complete or incomplete — approached this figure. In 1948 and 1956, less than 500 fish passed Woodbridge Dam. Stanislaus River The Rtanislaus Kiver is a good fall run stream for its size hut has almost no remaining spring run. A diversion dam (Goodwin Dam) blocks all salmon, and summer flows below it are low and warm. In the fall and winter, its waters are used for power generation and fluctuate violently. All counts and estimates were made by the Department of Fish and Game. In 1940 and 1941 the counts were made at lightly constructed weirs and were not complete. Successful tag and recovery exjieriments were conducted in 1947 and 1948. Estimates were made during most of the following years. The highest estimate was 85. ()()() in l!t5.3; the lowest (except for incomplete counts) was 4,000 in 1!)51. 11)57. and 1959. Tuolumne River hi some years the Tuoliiiniie Kiver has had fall rnns which were larger than tiiose of any Central \'alley stream excej)! the Sacramento. It has almost no spring run because its summer flows are low and warm, and fish cannot get past the La Grange Dam. Like the Stanis- laus, the Tuolumne is used for ]iower generation after the irrigation season is over, but its flow^s are larger and more stable. SALMON SPAWNING STOCKS 65 Counts were made by the Department of Fish and Game at the Modesto Dam fish ladder in 1940, 1941, 1942, and 1944. The 1941 count was incomplete. In the other years, the dam was left in and counting continued until the run had dwindled away to almost nothing, then the flashboards were removed for safety reasons. The U.S. Fish and "Wildlife Service made a count at the same place in 1946. This dam was condemned, and since 1947 it has been necessary to rely on esti- mates, all of which were made by the Department of Fish and Game. The biggest run of record was 130,000 in 1944; the smallest was 3,000 in 1951. Merced River Due to irrigation diversions, the Merced River is at present a mar- ginal salmon stream. There is a lack of water at critical times of the year. This stream has a poor fall run and poor spring run. No numerical estimate has been made of the spring run. All fall run counts and estimates were made by the Department of Fish and Game. Incomplete counts were made in 1940 and 1941. Estimates have been made every year since 1953. Since 1953 the highest estimate has been 4,000 fish in 1954. In all other years it has been below 500. San Joaquin River In the period under discussion this stream at first had an excellent spring run and a small fall run. Diversion of the San Joaquin at Friant Dam resulted in the drying up of the stream below the Sack Dam and in the virtually complete loss of both the spring and fall runs since 1949. All counts were made by the Department of Fish and Game, and all except those of 1948 and 1950 were made at the Men- dota Dam which is well below all spawning areas. In 1948 about 2,000 salmon were trucked to a canal which led them around the dry area below the Sack Dam. The count was made as the fish left the truck. The 1950 count was made at a temporary fish ladder on Salt Slough. The ladder was built to lead salmon from the slough into a canal from which they could re-enter the river above the dry section of streambed. Only 36 fish used the ladder. For all practical purposes, there has been no run since 1948. The highest run of record was 56,000 in 1945. EXPLANATION OF TABLES Counts Few of the counts made in the Central Valley are truly complete because they were made at counting weirs which were not entirely fish tight, at low dams which some of the fish could jump uncounted, or at removable dams which had to be taken down before the run was en- tirely over. When it is believed that the great majority of the fish were counted, the figures used in the accompanying tables are referred to as a "count." The counts (and incomplete counts) do not include any fish which spawned downstream from the counting station. 3 — 28642 66 CALIFORNIA FISH AND GAME en ir> en 1— 1 o 'i- a> r—* ^ >» a> ea >■ o •♦-• c a> E CO CJ TO ,-~ CO ^ .- .<2 a> •<- Q. H- Q. O ^ ,r, LU v> "O ~—l >,- c- cu o ro •a O CO t— -•-' =3 CO o M f c — c 5 ^ CO o. CO to o IQ o Eh > MS ° 5 c3 o J*; o - C O 0) « CO 0] cc — O i-frec-t ^ lO — CO iM X t~ O e«5 ^ e<3 IN i-H " cc K >> 5: 05 — rt CC-H-H IMT) a. ■X. c* •Scr=« s<= -r 3 ^ ^ C ■= r 3 ° E /• CS I -H -^ I I -^: t~ CO cc t^ ■* 'J' LO CO CI CD -H lO C3! O :K z£ ~. a "3 •r -c rr -3 -u ■* CC P3 M OS "O O O O ■* t^ ■* lO ^ CO t^ 00 CO ■-I r^ CO o t^ -< -f OC 00 t~ CO o; CO M CO CM — I (N — CO r^ M CO CO CO X « t^ _3 "a a> o ^ o CO (N CO CO t^ * ♦ * * iM O O O O in ■* t» T}< in o o o o o — 1— CO o t^ I-" CM ■«< CM LO — o o o C^ C: CO iM CD O — C^ CO •* <3> "O CO r- « 05 "3* ^T ^^ ^^ ^^ =a = -fc->^ r- c: C3 . &- etc S •S3- M c v: .2 js »&& O -c a. |£| •==== "T "E ^ca« ^ •^s: ^B'% ■o-'-S tL ^'zj S ^ o C~ S2 l:=s ti-a c» s = 2 S ci = 5 o v gll o = >>2 •' J- ersoii Keclai Most .^ -o ► c3 ?^ «?-e:f i-sl-^ ^11^ S CS O 1. C X — H . tx'm VI C^ ^ M^ ■si--^ = 3 . = QJ <: CO oS^-.'S = 03 , ^-1= n^ oj :£■ ^ ist^ w ^ — i- *J iti:i — o O >- CM CO f m »n 'O lo LO lO CD t^ 00 OS lO lO "O lO "5 OS El O sal:mox spawning stocks 67 C75 to CD 1 — I O (L> O) E CO o m oo 'sz k_ t/) o -H oa CO Tf ^5^ ^^ w^ ^^ ^^ en in CD t^ 00 o ^^ ^^ ^^ ^^ ^^ OS O -H O) CO T)< lo in lo lO 1-0 05 10 CD t> 00 05 lo in lo in in 05 ^ 3 ^ •o o a> K oJ-a •c cd a> OJ — H 0.0 r^! x: O --.„. — ^^ id " — >. .^ 3j tfi '— ' .=^ ? o ^ O 1. 03 o ji: ■c o =^ 53 C lO — .^ cr. o r: ^ c c3 C o O; t^ =^ ■u c ■a- c ■s -- a> :^ o rr Ja; c t: -, OJ '^ Q +J s "3 * c^ ^ X/l -^ >^ J2 ?3 m ^^ — ^ ^-^ en M v: , rt QO 4j O £i>o 3J S ^ bfl ml cti c C :2 hn o "« E •o C t- § rt J3 oS w dfa C5 73 TZ 5g 03 1. . .Si a; = •a U~^ OJ -^ — 0^ -S *J ol '^ Idlif Wi s. epar g=a^a - o :i ^i-n og :q O -g _ « ^ Q. ccp.2 ^ tJ.g'^c >>^ 5.2 -?;£ = ■= = ps^ CUm-h « rt OH Ed O 68 CALIFORNIA FISH AND GAME CD «— I o ro > a> a: "to > (U c: F c 3 zs (U o- -C TO O o ., CO as o 00 UJ oo CO _J CO (rt C m -- a> CO — ' < nj •*-* oo c TJ o 3 E "o CO c= C/0 — CuO c ^ c 3 o± (2 "rt >i Co." 2S -t Lh >■ C3 « a h q a) art — c >. a a a) S;3 rt (N CO •* a Oj a g P " t, « = S M — > -a ;§«! IC c^ c^ •^ o 1— ( I— ( t^ t>- o '!5 r- M CO 03 00 o ;c — 00 t^ »c -^ Tt* ^- ^H c^J -^ T)< lO -H c^) lO O M 00 t» CO -< — -r '-o o cc ^ o o o O lO •* CO CO o m o f-H ^ -f ttf U M tt bt O -i 00 0^ o D CO ■* s 5 Sfe. 1 a^ fa j: S OQ n wo £ £'-.2 S 5-s S •T- cfl — o u - _ _© 3 O Tji O >C (M a --I CO c< t~ O •* O -I' OfNC^fN'l' (N l04t~ S^E SH-I &> Uj:^iii lO O t^ 00 05 ^ ^ ^ ^ ^ OS O — C^ CO •* UO LO kO o o o O O t^ X 0* liO >o »o »o o OS A SALMOX SPAWNING STOCKS 69 m CD 1 — I cb cr CO o CO CO TO *4— -=t- o o UJ CO GO CO CO •o tr CO CO h- o = o C/3 -C 5 CO a. CO c o E CO CO ex CO O P5 C3 3 » 1-5 >3 H 'C rt 03 CO a> t-, p4 3 u mo o ^ ^5 o _ m =5 03 e >> 03 C^ rl^ O ffl UK o CO O CO 0 02 t^ 00 lO I> 00 03 O "-I C<< CO ■* in CO t~ 00 02 ^ ^ ^ ^ "^ O ■-< >P 70 CALIFORNIA FISII AM) GAME Incomplete Counts In many iiistnnces tlic ])r()|)()rt ion of tiie I'liii ^\ili(•ll ^ot past the counting- station ttiirccordcMl -was known or suspectod to be (piito large. Such fi^iiiith were a modification of the jjear originally developed at the Honolulu Biological Laboratory (Manii, 1955). Twenty baskets (210 fathoms per basket) of gear were fished at each longline station. The 12 droppers of a single basket were of varied length and in a set were arranged in three identical series as follows: 8, 2, 16, and 4 fathoms (Figure 3). Each dropper was buoyed separately to allow for a reasonably accurate estimate of the depth of capture. Longlines were fished during daylight, usually from 0800 to 1400 hours. The gear required about 30 to 40 minutes to set and from 60 to 90 minutes to haul. RESULTS OF FISHING Trolling Catch Of the three types of gear, Irolliiig produced the oidy albacore catches. In all, 314 albacore were caught on trolling gear and of these, 207 were tagged and released (Table 1). jj Q 0 C 9 9 ■ 9 9 9 9 9 9—fi — -f^ t en 2 to FIGURE 3. Arrangement of the droppers in a single basket (210 fathoms) of longline gear used on the Hugh M. Smiih albacore survey, 1959. ALBACORE FISHING GROUNDS 77 TABLE 1 Troll Catches for the N. B. SCOFIELD (Cruise 59S4) and HUGH U. SMITH (Cruise 52), Albacore Survey, 1959 Position Species Number caught Number tagged Surface tempera- Date of catch N. lat. W. long. ture degrees F. N. B. SCOFIELD 6/ 5/59 -- 34°46' 34°47' 34°49' 34° 52' 34°56' 34°59' 35°01 ' 35°42' 35°50' 34°50' 34°39' 34°20' 34°15' 34° 10' 36°31' 36°39' 36°45' 37°07' 37°30' 36°56' 3o°24' 34°48' 34°34' 34°25' 33°54' 33°40' 33°38' 33°17' 32°34' 33°08' 33°11' 33°13' 33°18' 33°19' 33°21' 33°26' 33°31' 33°33' 33°35' 33°38' 33°39' 33°46' 33°51' 33°37' 33°49' 34°02' 34°28' 34°43' 34°47' 34°53' 122°25' 122°28' 122°33' 122°38' 122°49' 122°54' 122°57' 124°45' 125°59' 126°06' 126°16' 126°22' 126°23' 126°26' 128°23' 128°22' 128°19' 128°18' 128°06' 127°38' 126°32' 126°04' 125°51' 125°43' 125°12' 125"00' 124°58' 124°40' 123°58' 124°06' 124°07' 124°09' 124°09' 124°09' 124°10' 124°11' 124°14' 124°14' 124°15' 124°15' 124°17' 124°18' 124°20' 124°30' 124°28' 124024' 124°29' 124°33' 124°34' 124°36' Albacore Albaoore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore 1 10 2 3 10 11 3 1 2 8 5 1 7 2 1 3 1 1 3 2 1 2 13 3 1 37 4 5 1 2 3 5 7 8 6 2 3 2 1 5 6 24 3 1 5 3 2 5 1 1 0 6 1 2 9 6 1 1 1 5 5 0 3 1 0 3 0 0 2 1 0 1 8 1 1 22 3 3 1 2 3 3 5 7 3 1 1 0 1 3 3 18 1 1 2 2 2 4 1 1 59.0 6/ 6/59 -- . .. 59.0 59.0 59.0 59.4 59.0 59.0 59.4 6/ 7/59 -. 60.1 6/ 8/59 - _ ._ 61.0 61.0 6/12/59 - -- -- 60.3 60.6 60.6 60.8 6/13/59 - - 60.8 60.8 61.0 6/16/59 61.0 60.4 60.8 6/16/59- 61.2 61.3 61.5 60.4 6/17/59 - .. 61.2 60.6 60.6 61.7 6/18/59 -- 59.5 6/19/59 6/19/59 - - - . - 59.5 59.5 59.4 59.5 59.5 59.7 59.7 59.7 59.7 60.3 60.3 60.4 60.3 60.4 60.4 60.1 60.8 60.3 6/20/59 - - -- 60.4 59.7 78 CALIFORNIA FISH AND GAME TABLE 1— Continued Troll Catches for the N. B. SCOFIELD (Cruise 59S4) and HUGH M. SMITH (Cruise 52), Albacore Survey, 1959 Position Species N\imber caught Number tagged Surface tempera- Date of catch N. lat. W. long. ture degrees F. 6/21/59 6/22/59 34='57' 35°00' 35°02' 35°20' 33°38' 33°32' 33°29' 33°25' 33°23' 33° 17' 32°20' 32°25' 32°26' 33°05' 33°12' 33°15' 33°25' 32°45' 32°41' 32°37' 32°33 ' 23°29' 33°09' 36°44' 27°26' 124°37' 124''38' 124°38' 123°51' 123°04' 123°02' 123°0r 123°00' 122°59' 122°57' 122°44' 122°43' 122°40' 122°32' 122°31' 122°30' 122°28' 121°30' 121°28' 121°26' 121°22' 155°07' 143°00' 132°26' 121°49' Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Albacore Dolpliin Skipjack Albacore Skipjack 4 4 1 1 1 1 10 8 3 2 5 6 4 2 2 4 3 2 2 5 3 1. 2 2 1 3 4 1 0 1 1 0 5 1 2 3 5 4 0 1 4 2 2 2 5 2 0 2 2 0 61.0 60.8 60.8 60.1 59.9 6/23/59-- - -- 60.6 60.4 59.9 58.6 58.8 61.3 6/24/59 61.3 61.3 61.2 60.8 60.6 61.0 61.0 H. M. SMITH 4/29/59 5/ 3/59. 61.2 61.2 61.0 73.0 63.9 5/ 9/59 - 60.8 6/13/59 64.8 ALBACORE FISHING GROUNDS 79 The Hugh M. Smith traveled approximately 6,000 miles during the 53 days of the cruise. This mileage was divided almost equally between the survey area, east of long. 125° W., and the preliminary route from Honolulu to this area. Lines were trolled for approximately 1,900 miles in the primary survey area and over 1,500 miles enroute, and 13 gill net and nine longline sets were made (Figure 4). Tavo albacore were caught on trolling lines and tagged some 500 miles west of San Fran- cisco. Three skipjack (Kaisnwonns pelamis) and a single dolphin (Coryphaena hippnrns) were the only other fish caught on this gear. The iV. B. iScofield traveled approximately 2,400 miles during the 25-day cruise. Lines were trolled for about two-thirds of this distance and in addition a single gill net set was made (Figure 5). The first schools of albacore were encountered between 90 and 120 miles west by north of Point Arguello early in the cruise. Subsequently, 312 were caught of which 205 were tagged and released at numerous localities. Severe northwesterly weather conditions prevailing throughout the northern survey area hampered fishing in most areas. Xo other species of fish was caught by the N. B. Scofield on trolling lines. Gill Net Catch Of 13 gill net stations occupied by the Hugh M. Smith, all but three were in the primary survey area. The first set was made on May 4, and the last on June 18. All were made in water ranging from 57.5 to 65.8 degrees F. at the surface. Xo albacore were netted. Six other kinds of fish were caught, including : skipjack, Pacific bonito (Sarcla chili- ensis), pomfrets, blue shark (Prionace glauca) and bonito shark (Isurus glaucns) (Table 2). A set was made on May 9, near where two albacore TABLE 2 Gill Net Sets Made by the N. B. SCOFIELD (Cruise 5984) and HUGH M. SMITH (Cruise 52), Albacore Survey, 1959 Position Species Number caught Surface tempera- Date of set N. lat. W. long. ture degrees F. N. B. SCOFIELD 6/11/59 35°35' 34°48' 38°48' 36°39' 26°59' 27°00' 27°00' 32°30' 32°08' 30°28' 28°50' 29°23' 27°33' 31°59' 128°28' 140°41' 1.35°06' 132°24' 121°59' 120°56' 119°31' 118°20' 119°35' 123°35' 117°57' 117°00' 122°15' 117°46' No catch .. ___ 1 25 4 7 1 2 6 4 1 3 1 1 1 4 4 1 61.2 HUGH M. SMITH 5/ 4/59 Bonito shark . 62 1 Pomfret 5/ 7/59 Blue shark ._ 57.5 Pomfret _ _ __ 5/ 9/59 Blue shark 61.2 Pomfret 5/22/59 Skipjack 65.0 5/23/59 No catch _ 65.8 5/24/59 No catch- 65.5 5/30/59 - Blue shark 62.1 Bonito shark-- 5/31/.59 6/ 4/59 Blue shark No catch 60.0 62.2 6/ 9/59..- .- Dolphin _ - 64.5 6/10/59 6/13/59 6/18/59 Bonito shark Pomfret Pacific bonito - 63.5 64.8 65.4 Blue shark Bonito shark 80 CALIFORNIA FISH AND GAME UJ a; o < UJ 2 t- lll -1 < _l tn O (- llJ o z 2 2 _J o m o o — ^ z 2 -D oc o => < I- o -1 ZO a< (C. ^ \ \ -V \ o-^ in o T' ^ o in O in ALBACORE FISHING GROUNDS 81 UJ (r o o < z z 3 o K LU CC l- -1 Z UJ X -i 03 O o -^33 tE -■ 3< f- Z O 2 O D® If) IrO O _3_ in m O rO O 4 — 28642 82 CALIFORNIA FISH AND GAME lllll' liiu's, l)u1 (jiily blue sliarks and pomfrets had been caii^lil on I ml were caii}j:ht. A siiifjle gill net set from the N. B. Scofield, approximately 390 miles west by iioiili of Point Arp'iiollo on June 11. in ()1.2-degree F. water, eauyht no fish. Longline Catch The first of nine longline stations occupied by the Hugh M. Smith was on :\ray 6, and the last on June 17. All l)ut two were in the primary survey area. Surface temperatures at the longline stations ranged from ()().!) to 64.7 degrees F. Xo albacore were caught, but three other kinds of fish including: bigeye tuna (Parathunnus sibi), hammerhead sharks (Sphrirna sp.) and bhie sharks were taken (Table 3). The .V. B. Scofield (lid not use this gear. TABLE 3 Longline Sets Made by the HUGH M. SMITH (Cruise 52), Albacore Survey, 1959 Position Species Number caught Surface tempera- Date of set N. lat. W. long. ture degrees F. 5/ 6/59 36°48' 33° 19' 28°56' 27°23' 31°07' 30°03' 29°38' 28°15' 30°47' 138°05' 128°01' 123°27' 122°09' 124°56' 120°58' 117°55' 119°34' 119°10' Blue shark 4 2 1 3 2 6 1 1 4 1 61.3 5/17/59: 5/21 /.5Q Blue shark 60.9 No catch 63.8 5/22/59 No catch, 64.7 6/ 3/59 Blue shark- -- 61.7 6/ 6/59 Blue shark 61.9 6/ 8/59 Bigeye tuna. 63.6 6/12/59 Hammerhead shark Blue shark. - 64.1 6/17/59 Blue shark 62.5 Hammerhead shark SIZE RANGE OF THE ALBACORE CATCH Based upon a frequency distribution of ID!) albacore tagged b.\' tlie N. B. Scofield (Table 4), over 80 percent of the catch was within the size range 630 to 680 mm. fork length (approximately 11 to 14 pounds). Lengths of untagged fish were similar and none was outside of the above size range. Weights recorded for the two albacore tagged from the Hugh M. Smith were 8 and 12 pounds, well within the overall size distribution. SEA SURFACE TEMPERATURES AND ALBACORE OCCURRENCES liather comprehensive records of sea surface temperature were main- tained aboard both vessels. In general, surface temperatures within oO miles of shore varied from 54 degrees F. around Santa Rosa and San ^liguel Islands to over 70 degrees F. along the immediate southern California coast and within a few hundred miles of the Hawaiian Islands. Offshore in the actual survey areas tlie range was between 57 and 65 degrees F. Surface temperature records were suf^cientl.v detailed to make it possible to construct rough isotherms witliin tlie survey area. Plotting ALBACORE FISHING GROUNDS 83 TABLE 4 Lengths of 199 Albacore Tagged from the N. B. SCOFIELD, Albacore Survey, 1959 Length (cm.) Frequency Percent Length (cm.) Frequency Percent 56 1 2 1 2 7 15 36 48 34 0.5 0.5 1.0 0.5 1.0 3.5 7.6 18.1 24.1 17.1 67 68 69 70 71 72 73 74 75 81 25 15 8 0 0 1 1 1 0 1 12 6 57 --- 7.5 58 - --- 4 0 59 60 61 _ --- 0.5 62 _. _ _- 0.5 63 -- --. 0.5 64 65 -- 66 0.5 albacore occurrences on a chart of these isotherms shows the relation- ship of the catches to surface temperature (Figure 6). Ninetj^-eight percent of the albacore caught were from the rather restricted temperature range of 59.0 to 61.3 degrees F. (15.0 to 16.3 degrees C.)- The remaining two percent were caught within plus or minus 0.4 degrees F. from these extremes (Table 5). Though surface temperatures where albacore occurred during May and June 1959 tended toward the lower extreme, they were predominantly Avithin the range of 60 to 69 degrees F. from which California fishermen reported over 90 percent of their catch during the period 1955 through ]957. TABLE 5 Albacore Troll Catches by Temperature, Albacore Survey, 1959 Temperature Catch Temperature Catch Degrees C. Degrees F. Number Percent Degrees C. Degrees F. Number Percent 14.8 58.6 3 0.96 15.8 60.4 44 14.01 14.9 58.8 2 0.64 15.9 60.6 23 7.32 15.0 59.0 30 9.55 16.0 60.8 17 5.41 15.1 59.2 0 0.00 16.1 61.0 29 9.23 15.2 59.4 18 5.73 16.2 61.2 48 15.29 15.3 59.5 24 7.64 16.3 61.3 28 8.92 15.4 59.7 9 2.87 16.4 61.5 3 0.96 15.5 59.9 9 2.87 16.5 61.7 1 0.32 15.6 60.1 60.3 6 20 1.91 6.37 15.7 Total 314 100.00 SUMMARY In an attempt to obtain an early opening for the 1959 season and to learn the route of the spring migration of albacore a joint, pre- season survey of the fishing grounds was carried out by the California Department of Fish and Game and the Honolulu Biological Labora- tory, U.S. Bureau of Commercial Fisheries. 84 CALIFORNIA FISH AND GAME o -a ALBACORE FISHING GROUNDS 85 2. Tlie California Department of Fish and Game vessel X. B. Scofield surveyed the offshore fishing- grounds north of Lat. 32° N. from June 1 through June 25, 1959. The Bureau of Commercial Fisheries vessel Hugh M. Smith surveyed to the south of Lat. 32° X. from April 28 through June 19, 1959. 3. Fishing gear consisted of feather and bone jigs, longlines and gill nets. 4. Trolling north of Lat. 32° X. produced the only catches of albacore. Of 314 caught trolling, 207 were tagged and released. 5. Fourteen gill net sets and nine longline sets caught no albacore. These two types of gear did produce small catches of bigeye tuna, skipjack. Pacific bonito, i)omfrets, dolphin, blue shark, bonito shark and hammerhead shark. 6. The predominant size group of albacore caught was from approx- imately 11 to 14 pounds. 7. Offshore sea surface temperatures ranged from about 57 to 65 de- grees F. Albacore occurrences were limited to a range between 58.6 and 61.7 degrees F. ACKNOWLEDGMENTS The authors wish to extend their gratitude to the captains and crews on the N. B. Scofield and the Hugh M. Smith. Without their splendid support, often under trying conditions, the data presented in this paper could not have been obtained. LITERATURE CITED Clpmen.s, Harold R. 19.")."). Catch localities for the Pacific alhacore (Thuii mis (jermo) landed iu Cali- fornia, 1951 through 19.J.3. Calif. Dept. Fish and (iame. Fish Bull. 100, 2S ,,,,. Clemens, Harold B. n.d. ^Migration and growth of the Pacific albacore (Thunnus genua). Calif. Dept. Fish and Came, ^lar. Res. Oper. Manuscript. Graham, .Joseph .T., and William L. Craig n.d. Oceanographic observations made during a 1959 albacore (Thunnus geniio) survey off the North American west coast. U. S. Bur. Comm. Fish., Hono- lulu Biol. Lab. INIanuscript, 1960. (To be published in Spec. Sci. Kept. : Fish. Series.) Graham, Joseph J., and Herbert J. Mann 1959. Construction and catch selectivity of albacore gill nets used in the central north Pacific. U. S. Fish and Wild!. Serv., Comm. Fish. Rev., vol. 21, no. 8, pp. 1-6. Mann, Herbert J. 1955. Con.struction details of improved tuna longline gear used by P.O.F.I. U. S. Fish and Wildl. Serv., Comm. Fish. Rev., vol. IT, no. 12, pp. 1-10. Scofield, W. L. 19.56. Trolling gear in California. Calif. Dept. Fish and Game, Fish Bull. 10.3, 45 pp. CONSTRUCTION AND OPERATION OF A SMALL BOAT TRAWLING APPARATUS' WAYNE J. BALDWIN Department of Zoology University of California, Los Angeles The constant need for improved collecting devices stimulates experi- mentation for new and more efficient methods. Much of the research of the fishery biologist depends upon the development of specialized equip- ment. An inexpensive and completely portable trawling apparatus devel- oped at U.C'.L.A. has substantially improved our trawling success for shallow water fishes. It is designed to be used in small boats pow- ered by an outboard motor, and can be efficiently operated by two people in waters deeper than 150 feet. Commercial trawlers are a rich source of specimen material for the collector but they have a number of disadvantages. They fish with large mesh sizes, in restricted localities, in certain seasons, and are not always available. Quite often many good collecting areas are missed because of these reasons. Minimum mesh size is an excellent conservation meas- ure but allows many of the smaller and equally important specimens to pass through the net. Because of their size, commercial trawlers are compelled to operate several miles out from shore, thereby leaving an important inshore zone unavailable for collecting specimens by this means. Many rare and important specimens in the U.C.L.A. fish collection were obtained by collecting in the shallow inshore zone with the port- able trawling apparatus. It permits the fishery worker to operate freely in these shallow areas normally out of reach of the commercial trawler. DESIGN AND EQUIPMENT A portable trawling winch and component equipment similar to ours can be made to fit many designs of small boats that use an outboard motor. Boats having moderately flat bottoms, wide beams, and high freeboards are recommended. It may be necessary to install additional supports to the transom and seats due to the weight and stresses sub- jected to the boat by the trawling eriuipment. We have found that a standard 15^-foot fiberglass outboard hull worked efficiently with the addition of two quarter knees to the transom and greater support to the seats. Boats smaller than this are not recommended since it is doubtful that they could be used safely with this equipment. The weight of two operators, all the trawling equipment, the outboard motor and two fuel tanks is in the neighborhood of 700 pounds. These plus the down- 1 Submitted for publication, April, 1960. (87) 88 CAIJFORNIA FISH AM) (,AMi: ward i'orrc of the 1r;i\\l r:\\)\r on llir sicfii subject llic hull to a wrijiht load that can l)r saTclN- handled (.nly by a hir^cr l)()at. At least a six- foot lieaiii and a ir)-iiieh freeboard at lho stern are recommended. Most ()n11)oai-(l hulls are eoiist I'ueted to aeeoinino(hito a standai'd-shank ont- boai-d motor with usually a maximum of 1.") inclics of freeboard at the stern. It would be advisable to use a lon<>:er shank outboard motor, thereby allo\viu iininids Oliio Speed Keducer ■'>•"• pinnids Trawl Cable Drum l-'5 ixiiinds (>{)() feet of ■y^c/mch steel cable ^~< iKnmds "CJypsy Head" 1"> pomHJs Trawl Frame .Vsseinlily -t'l immiikIs IJeeause of the strong backwai'd |)ull of the trawl cable on the winch it is necessary to attach a stress cable to ])revent the forward seat from being ])ulled out. This is easily done by making a V-shaped cable bridle with a lurnlaickle fastened to one end and a bi-ass spring suaj) fastened to each of the other tA\ii ends. The bi'ass s|)ring snajis attach to a stationary I'ing at each guuAvale near the bow. The tui'idmckh^ hooks onto the winch fi-ame and is tightened slight l.v so that any ba(d\ward TRAWLING APPARATUS 89 movement of the trawl winch will be stopped by the stress bridle thus preventing' damage to the forward boat seat. The fV-inch steel cable spooled onto the cable drum passes back and over the stern with a net bridle spliced on the end for attaching the two otter boards. The operating depth of the trawl winch may be extended by equipping the cable drum with a smaller diameter cable. The principal reason for using a i\-inch cable was for ease in handling in case of equipment failure requiring manual pulling. A pipe frame fitting into four brass sleeves mounted on the inside of the transom supports a pulley assembly on which the trawl cable rides at all times during operations. The pipe transom frame also provides a convenient place for hanging the otter boards when the net is brought up. As a convenience in handling specimens, a removable sorting table is mounted onto the gunwale between the two boat seats. A removable canvas awning supported by four pipe uprights can be easily added to protect equipment and personnel from the elements. Some type of protection from the sun and weather is quite important when operating in tropical localities where extremes in temperature and humiditv are common. FIGURE 1. The small boat trawling apparatus in operation showing the net and otter boards in position to be set. Photograph by the author, January 1959. I This trawling apparatus can be used for many purposes with little or no change in design. It can be used for towing plankton nets, dredges, small beam trawls, and with the addition of a "gypsy head" for raising and lowering various types of fish traps. Transporting the 5—28642 90 CAUFORXTA KISII AND f:A:\rE boat and (•(|iii|)iiiciit is no iii'dhlciii since llir hojii cjin be can'icd on a standai'il lio;it li-;iilci- and llir ti'awlini!' apjiaratus loaded inio the towini! \rliiclc alon;^ with llic other coHcctiiig cMiuipincnI. OPERATION OF EQUIPMENT Two pel-sons can operate the ei])e frame (Figure 8) is a simple brass pulley wheel 4 inches in length, -l inches in diameter, mounted in a stainless steel housing. A 1-inch shaft welded to the underside of the pulley housing fits into a vertical sleeve at the center of the transom frame and is held in ])osi- tiou by a locking pin. The locking pin prevents the ])ulley housing frcmi turning and insures against accidental loss over-board of the pulle\' as- sembly. A brass spring latch on top of the pulley housing which can open and close, prevents the trawling cable from slijjping off the pulley wheel. Many variations in design are acceptable for a stationary pulley FIGURE 3. The pipe transom frame supports the pulley assembly on which the trawl cable ricJes during operations. The metal hooks at each corner are for hanging the otter boards. Phofograpb by fhe author, January 1959. TRAWLING APPARATUS 93 of this type but the pulley wheel itself should be wide enough to allow free passajie of the trawl cable and bridle. The transom frame (Figure 3) is made of f-inch galvanized pipe and is used to support the pulley assembly over the stern. Two upright legs, 45 inches in length are joined to a 44-ineh crossmember on which a sleeve is welded at the center to receive the shaft of the pulley housing. The crossmember and uprights are joined by two 90-degree elbows and spot welded to prevent rotation. On top of each 90-degree elbow a short hook is attached for hanging the otter boards when not fishing. The lower section of the transom frame should be bent to coincide with the angle of the boat transom allowing the two uprights to maintain a vertical position. Transom Sleeves Four 3-inch brass sleeves are bolted to the inside of the transom in such a position as to receive the two legs of the transom frame. Each sleeve is constructed of J-inch brass stock with an inside diameter of 1^ inches. A 2-by-4-inch brass plate is brazed to the sleeve and used to mount it to the boat transom by four ^-inch brass bolts. Two of these sleeves (Figure 4) are mounted one over the other near each corner of the transom, each pair placed 45 inches apart to receive the pipe uprights of the transom frame. The lower sleeves have a brass stop brazed onto the underside to retain the frame uprights in position. It is these lower sleeves that receive all the downward force created by the trawl net onto the cable. Enough spacing should be allowed between the brass sleeves and the f-inch pipe uprights to prevent freezing due to encrusting salt and sand deposits. Specimen Sorting Table Made from one sheet of ^-inch plywood, 36 by 36 inches, a sorting table was added for convenience in handling specimens (Figure 5). To all four edges, a 3^-inch high side board was added with drain holes cut into the outboard edge. The table is set onto the left gunwale and held in place by three wooden blocks attached to the underside which fit the contour of the gunwale. The inboard end of the table is sup- ported by two removable ^-ineh galvanized pipe legs that screw into pipe flanges bolted to the underside. After the catch is emptied from the net onto the sorting table it can be easily washed free of mud, sorted, and the specimens placed into containers. This not only prevents the boat and equipment from becoming covered with mud but helps keep the specimens in a clean condition for preservation. A sorting table of this nature is an important feature since a majority of the specimens are usually collected along Avith unwelcome mud and refuse. As an added convenience the surface of the table is painted a light gray and can be used as a background for photographing specimens. Trawl Net and Equipment Since this method of trawling is designed to operate with a single line, it is necessary to construct a net bridle at the end of the trawl cable for attaching the otter boards. Two lengths of f^-inch stainless steel cable at least 25 feet in length can be simply spliced onto the end of the trawl cable. If desired, a small swivel may be added, but it 94 CALIKOHXIA FISH AND (iAMK % X FIGURE 4. The transom sleeves receive the uprights of the pipe transom frame. The quarter knee at left was added for support to the transom. Phofograp/i by fhe author, January 1959. should he small cikiu^Ii lo fi-ccly |)ass ovci- the liawi pulley and onto the cable drum. A wire rojtr iliimhle is spliced onto each end of the bridle cables allowiu'r the ollei' hoaids lo be attached with metal shackles. Li 0.05). On examining the specimens washed ashore it soon became apparent that the sexes could be readily distinguished. The males, as contrasted with the females, possessed short, red hairs which were more numerous on the chelipeds, the tail fan and especially the ventral aspect of the thorax. Only four pairs of pleopods were evident in the females. There were five pairs of abdominal appendages in the males, but the first two are modified in a direction away from tlie usual paddle-like form, and perhaps are involved in a copulatory function. T]i(>se two ]iairs of ap- pendages were rather slender and extensible. Of 853 specimens sexed. 213 were females — giving a ratio of one female for every three males. Seventy-seven percent of the females were gravid, many in an advanced state. The red crab, besides its importance as food for some of the larger pelagic fishes, such as yellowfin tuna and skipjack (Schaefer, 1959), is preyed upon extensively by benthic as well as inshore forms, when 100 CALIFORNIA FISH AND GAME FIGURE 1. Red crab with pencil pointing to scallop on cheliped. Phofograph by Dennis Rowedder, November 1959. on occasion it approaches more closely to tlie coast. Stomach analyses have shown that at least six species of rockfishcs have fed on them. These are Scbastodes vcxiUaris, S. miniatus, S. rosaceus, S. paucispinis, S. chlorostictiis and S. scrranokhs. The lingcod, Ophiodon elongatus, was also fonnd to have eaten this crustacean. One individual of the red- breasted merganser, Mcrgus scrralor, Avas seen gulping down a red crab in the surf line. During the period of the Monterey invasion, many of the littoral rocky regions frequented by shore birds took on a measly appearance — due to the indigestible, scarlet-colored exuvia left in the STRANDING OF PELAGIC CRABS 101 faeces by the birds. This was particularly noticeable in one area fre- quented by Heermann's gulls, Larus heerma^ini, and California gulls, L. calif or nic lis, in front of the Hopkins Marine Station. ACKNOWLEDGMENTS Thanks are due Messrs. J. B. Phillips, Carl Boyd, John B. Fitch, F. G. Alverson and C. E. Blunt, Jr., for their assistance in the prep- aration of this paper. LITERATURE CITED Hopkins ^Marine Station 1960-1958. CCOFI hydrographic data collected on approximately weekly cruises on Monterey Bay, California. March, 1954-December, 1959. Calif. Dept. Fish and Game, Mar. Res. Comm., 209 pp. (mimeo.) Hubbs, Carl L. 1948. Changes in the fish fauna of western North America correlated with changes in ocean temperature. Sears Found., Jour. ]\Iar. Re.s.. vol. 7. no. 3, pp. 459-482. Marine Research Committee 1957. 1957 : the year of warm water and southern fish. Calif. Dept. Fish and Game, Mar. Res. Comm., 15 pp. (mimeo.) Schaefer, Milner B. 1959. Report on the investigations of the Inter-American Tropical Tuna Com- mission for the year 1958. Inter-Amer. Trop. Tuna Comm., Ann. Rept., a pp. A, pp. 34-74. Schmitt, Waldo L. 1921. The marine decapod crustacea of California. Univ. Calif. Pub. Zool., vol. 23, 470 pp., 50 pis. Skogsberg, Tage 1936. Hydrography of Monterey Bay, California. Thermal conditions, 1929-1933. Amer. Phil. Hoc, n.s. vol. 29, 152 pp. THE EXTERNAL MORPHOLOGY OF THE FIRST ZOEAL STAGES OF THE CRABS, CANCER MAGISTER DANA, CANCER ANTENNARIUS STIMPSON, AND CANCER ANTHONYI RATHBUN' ROBERT D. MIR Department of Zoology The College of the Pacific, Stockton, California INTRODUCTION In September 1958, the writer accompanied marine biologists of the California Department of Fish and Game on the research vessel, N. B. Scoficid to acqnaint himself with crab collection techniques nsed on that vessel. After the crab {Cancer magist'cr) season opened in 1958, arrangements were made to accompany Mr. Vern Gingrich on his com- mercial crab boat, Merfico IV, to collect female crabs bearing egg masses. Consequently several such trips were made during the course of the eg^ bearing season and several samples of crabs (Cancer spp.) were obtained. A trip was taken to Scripps Institution of Oceanography at La Jolla, California to consult with Dr. Beatrice M. Sweeney on growing minute plants and animals as possible food for the larvae. Several samples were obtained and transported back to the Pacific Marine Station at Dillon Beach, California for cultivation. An excur- sion was also made to Eureka and the Oregon border hoping to collect additional specimens. A search of the literature showed that no papers dealing with the zoea of local Cancer crabs were available. Literature on the northern Pacific brachvuran zoea is slight. The prominent papers are those of Aikawa (1927, 1928, 1929, 1933, 1937). These treat a variety of genera and offer useful information for the determination of family character- istics but do not identfy to species any member of the genus Cancer. A single paper (Hart 1935) covers some of the Brachyura of the north- eastern Pacific but again no member of the genus under consideration is included. MATERIALS AND METHODS Where the time required to transport specimens to the laboratory was shorter than tw^o hours, the berried females were placed in a lug box, covered with wet burlap, and kept out of the direct sun. Sea water was poured intermittently over the box to keep them moist and cool 1 Submitted for publication March, 1960. This study is a contribution of the Pacific Marine Station of The College of The Pacific prepared by service agreement with the California Department of Fish and Game. It is the first report on larval forms of Cancer crabs of the W'est Coast. Only through such research is it possible to Identify and study the very young of such economically important species as the market crab. A determination of the success or failure of year classes would per- mit harvest of the resource at its greatest potential. (103) 104 CALIFORNIA FISH AND GAME s. Suisan Gakkwai Ho. vol. 4, no. 4. pp. 270-296. (In Japanese) 1928. Characteri.stic features of zoea for classification. Suisan Gakkwai Ho, vol. 23, no. 4, pp. 181-191. (In Jai)anese) 1929. On the larval forms of some brachyura. Records Oceanog. Works in Japan, vol. 2, no. 1, pp. 17-55. 1933. On the larval forms of some l)ra<'hyura. 2. A note on indeterminal)le zoeas. Records Oceano};'. Works in Jai)an. vol. 5, no. 2, pp. 124-2.")4. 1937. Further notes on hrachyuran larva. Records Oceanog. Works in Japan, vol. 9, no. 2, pp. 87-162. Costlow, J. D.. Jr.. and C. G. Bookhout 1959. The larval development of CalUnectes sapid ks (Rathbun) reared in the laboratory. Biol. Bull., vol. 116, no. 3, pp. 373-396. Galtsoff, P. 1937. Culture methods for invertebrate animals. Ithaca, Conistock Publ. Co., pp. 33-34. Hart, J. F. L. 1935. The larval develojiment of British Columbian Brachvurans. 1. Canadian Jour. Res., vol. 12, pp. 411-423. Lochhead. M. S., and C. L. Newcombe 1942. Methods of hatching eggs of the blue crab. "N'irginia .Tour. Sci., vol. 3, nos. 2-3, pp. 76-86. Schmitt, W. L. 1921. The marine decapod crustacea of California. Cniv. Calif. Publ. Zool.. vol. 23, 470 pp. NOTE WATERFOWL BOTULISM OUTBREAK IN SAN JACINTO VALLEY, RIVERSIDE COUNTY, CALIFORNIA Botulism of epidemic proportions developed in Tulare Lake and many other waterfowl areas in Central and Southern California in the fall of 1958. This report summarizes field observations of the disease at the H C & S Ranch near Lakeview, Riverside County, California during the fall and winter of 1958-1059. The II C & S Ranch contains about 160 acres of shallow, artificially flooded ponds lying in the alkaline lake bottom of the former Sau Jacinto Lake. The ponds are partially flooded during the summer for cultivation of water grass {Eclxinocliloa cniscjaIJi) and alkali bullrush (Scirpus paludosus) and are almost entirely flooded from October through February for the hunting season. Sick and dead ducks became evident the first week of September 1958 and more were found continually until March 1959. From Septem- ber until January dead ducks were gathered up every day or two and buried. A count on September 28, 1958 w^as ciuite typical and showed 30 pintail (A)ias acuta), three green-winged teal (Anas carolinensis) and one mallard {Anas plaiyrliynclios). The largest number of dead birds gathered was on November 20, 1958 when a count of 103 Avas made, although the ponds were not completely searched. It is estimated that 1,800 to 2, 000 ducks were gathered up and buried during the four and one-half month period. This approximates the recorded hunting kill of 2,110 ducks for the same season on these ponds. An unusually hot and dry fall probably played a part in this outbreak of botulism. Even in December the temperature was above 80 degrees for a number of days. However, in November when the outbreak of disease was most evident the water was not Avarm in that ice formed on the ponds during several nights. This suggests that dangerous amounts of toxin were present in the ponds at times when the botulism organism was presumably not growing, since its reproduction is associated with warm water temperatures. Bonventre and Kemn (1959) reported that at 10 degrees C. or below, metabolic activity of C. hoiulinum type A was not detectable and that between 10 and 18 degrees C. there was partial growth and toxin synthesis. Many species of birds were found dead or sick with the typical symptoms of muscular weakness and diarrhea on or about the ponds. Pintail, green-winged teal, mallard and widgeon {Mareca americana) were the most commonly afflicted ducks and about 75 percent of the«e were pintail. Other species included the shoveller (Spahda clypeata), cinnamon teal {Anas cyanopfera), gadwall {Anas sfreperus), avocet (Reciirvirostra americana), sora {Porzana Carolina), red-winged black- bird {Agelaius phoeniceiis) and pheasant {Phasiamis colchicns). Con- (113) 114 CALll-UKMA FISH AND UA.ME spieiiously absent from this list is the coot {Fulica anicricnva) altlioiifrli several hundred were ])resent durinji' the entire period of observation. Tlu'iH' were some coots killed or eripj)led by liuiiters, ijul none were found before or after the huntin<2: season where it appeared that they had suecniiihcd lo l)()tulisiii. 'I'liis might be explained by their food habits. Their stomachs conlained mostly <2:reen vejictable matter, in contrast to the ducks whose stomachs contaiiu'd ])rcdomiiuintly water jrrass seed and allwili bullrush seed which bad been sifted out of the watci- and niuil of the shallowci- ponds. No ])revions outbreaks had been observed in this vicinity in the preceding four years of regulai- waterfowl observation. However, Frank Motte, owner of several small duck clubs in this area, stated that there was a conspicuous outbreak about eight years ago. LITERATURE CITED I*>(>u\(Mit IT. r. v.. and K('iii|ic. ].. L. Ill-lit. I'liysiolosy of toxin production hy Clostridiiim hot iiliii ii m. typt'.s A and P>. Apjilied ]Mici'ohioloi;y, vol. 7. no. B, p]i. .372-.377. Harold M. HilJ, M.D.. and Laurence M. Orahaw, 219 Cajon Street, Rcdlands, California, J itly J. 960. BOOK REVIEWS Manual of Game Invesiigafional Techniques Edited by Ilt'iuy S. :\lusl)y ; Tlic Wildlife Society, c/o Virginia Coop. Wildl. Res. Unit, Dept. of Forestry and Wildlife, Blacksbiirg. Virginia, 1960 ; approx. 360 pp., illus., $4.50. The Wildlife Techniques Committee of the Wildlife Society is responsible for the preparation of this manual, and it is released under the sponsorship of the Wildlife Society. In the words of Dr. Mosby, the committee chairman and editor, the purpose is to report the best procedures as currently developed and understood. Xo effort is made to catalogue all techniciues, or to establish standard technicpies. The format and page numbering will facilitate revisions in future editions, since it is realized that techniques are continually being improved or replaced by better ones. The manual is divided into 17 sections, each with its own pagination as follows: Techniciues and the (Jame Investigator, Record Keeping l)y Means of Field Notes and by I'hotography. Reconnaissance Mapping, Evaluation of Habitat, Estimating the Numbers of Game Populations, Criteria of Sex and Age, Animal Population Analysis, Preserving Biological Material, Post Mortem Examinations, Capturing and Marking Wild Animals, Pleasuring Hunting and Other ^Mortality. Control of Nui- sance Wildlife. Food Habits I'rocedures, Presentation of Numerical Data, Using Wildlife Literature, Project Planning, Reporting Research Results. The method of presentation draws on examples which illustrate the fundamentals upon which the several techniques are based. Specialists are certain to find omissions and may choose to quarrel with the authors on their choice or presentation of material. In a work of this nature, such pitfalls are unavoidable. In general, every wildlife worker should find this manual to be of great value. The volume of literature currently being produced in the wildlife field is immen.se. A specialist is hard-put to keep up with developments in his particular area while the effort recpiired to forage through the entire galaxy of wildlife literature is staggering. It is only through compilations and manuals, such as this, that a person can hope to dig out information and techniques with any degree of speed and efficiency. I feel that every wildlife worker will profit by owning this manual. The cost is ridiculously h)w for this day and age. I sincerely urge that each of you in the business add this to your personal library. — Fred L. Jones, California Department of Fish find Ga.me. Northern Fishes By Samuel Eddy and Thaddeus Surber ; Charles T. Brauford Company, Newton Centre. Massachusetts, revised edition 1960 ; xii + 276 pp., illus. $5. '"Northern Fishes", first printed in 194.3, has been revised and reprinted in an attractive format. The introductory sections have been expanded and brought up to date. They discuss such things as angling methods and various technical aspects of fisheries management for the layman's articles. The main body of the book, dealing with identification of some 150 species of fishes in the northern ^Mississippi drainage and with the characteristics of these fishes, is little changed from the original edition although some of the keys have been improved. The black-and-white illustrations of 86 species are generally attrac- tive and adequate. In most cases, the plates from the first edition were used again, however, the printer did a much better job with them in the new edition. I'nfor- tunately, this is not the case with the color plates which are poor. — Alex Calhoini. California Department of Fi,sh and Game. (115 ) 11() CALIFORNIA IMSII AND GAME The Sea off Southern California, a Modern Habifaf of Pefroleum J'.y K. (>. Kin.rv : .lulm Wil.-y .V Suns, Inc., \.'w V.nU, T.KU) ; xi + 366 pp., 248 figs., 1 niMp. .$12..')(» To tho nniiifornii'd. :\ Imsty kIjuico nl (lie title leave.s a feeling the .subject fould have been t liKruuglily cuxered in a volume half this size. However, a critical perusal ()f th(» table of contents, clironological insix-clion of a dozen or so of the carefully selected illustrations and ten minutes of attentive reading in the text will dispel utterly any such preconceived fears. In fact, a complete reversal of thinking is likely to occur in which one wonders how such a vast undertaking could have been accomi)lished in so few jtages. The publishers could not have chosen a more coniix'tent or well-versed authority to compile this volume. l>r. Emery's knowledge of the area — its composition, struc- ture, geology and natural history — has been obtained primarily from first-hand, on- the-spot studies. This reviewer recalls a time several years ago when, simply by examining a number of lots of rounded, beach-worn cobbles removed from sealion stomachs. Dr. Kmery correctly identified the specific localiiics (islands, beaches, etc. ) where the sealicuis had been i-ollected. To present a clearer picture of the book's scope, a listing of the chapter headings seems in order. Chronologically these are : Phj/siopraphi/, Liflwloi/i/, Stnictui-e, Water, Life, Sediments, and Econotiiic Aspects. Within the chapter on physiograjihy are nine subsections dealing with exiiloration, general description, coasts, shehcs and baid< tops, basin and tnuigh slopes, submarine canyons, basins and troughs, continental slope, and abyssal sea floor. Six subtitles are included under the chapter on life — not one of the strongest sections of the book. The 22 ages of references (several hundred entries), the author index and the subject index are extremely heli>ful for searching ou( specific details or for finding a more complete coverage of a particular suiiject. A map of the southern California coast (scale 1 : .">()(),(>(>(); contour interval 30<> feet) showing the relation of land and sub- marine topography is tucked under a flap on the inside of the back cover. A cursory examination of the entire volume and careful reading of nunuu-ous select sections revealed several interesting conclusions: 1, stressing petroleum in the title is misleading and could cause a nmltitude of workers, interested indi\i(luals and students to overlook the book, even though it contains just the type of information they would want ; 2, the author's style is such that no one, regardless of back- ground, should have difficulty understanding what he has written ; and 3, by having covered tcomi)]etel.v but not exhaustively) such an expanse of material in so few pages, the author has i)roduced one of the most thought-provoking \-olumes I have encotintered in years. Regrettaidy, the jiurchase price will restrict ownership of this highl.x' desirable item. — Jolui E. Fitch, Volifoniid Depart mcnf of Fisli and Game. Lisf of the Marine Fishes of Canada By 1). E. McAllister. National Museum of Canada, Ottawa. Bull. 168, iv + 76p., 1960. .$1.2"). All species of fish recorded from the hr.ickisii and ni.ii-ine waters (ihrei^ oceans) of ("an;id:i have been includey merely diiTeren- tiates tlie families without rc'fereiice to host, whereas a similar key is presented of the cestode f;enera of poultry, and two charts are devoted to those affecting selected mammals. On the other hand there is a profusion of information on the nematodes that is not only replete with reference to the variety of hosts affected but is keyed to the individual species in >jreat detail. A hint of this disparity was acknowledged by I»r. Whitlock in the i)reface, "It woiibl be especially useful if some platyhelminth specialist could find an objective way of represent in;; his material." It is true tiiat the subject of the nematodes is more extensive than tli:it of the other helminths. However, there is undue emphasis as indicated by the l()!t pajjes that cover the Nematoda, whereas Cestoda are given 1") jiaRCs !ind the Trematoda only five pasps. The protozoologists will not be hapjiy when they read in the introduction "Al- thou>;h traditionally protozoology has been consideri'd a comi)onent of Veterinary I'arasitology, the line between the bacteria and the protozoa ... is exceedingly fine or even nonexistent. ... In the temperate regions of the world jirotozoology is logically an appendage of bacteiiology." This may be classified as a "sin of omis- sion" in a book with the title "Diagnosis of Veterinary Tarasitisms." The first third of the book discusses the field of veterinary entomology with useful albeit sketchy keys to the genera concerned. In the entomology section as with the helminths, the parasites afflicting wildlife are either ignored, mentioned in passing, or discussed in detail only if the hosts can be feral as well as domestic. On the other hand where there is an overlap of species into the field of human i):irasitology ade- quate coverage is given by the author. Dr. Whitlock has taken text from the authorities in the field and his discussions are predominantly composed of quotations from their works. When he relies on liis own knowledge and cajiabilities as an author his style is flowing, easy to follow, and he imparts an interest in what might otherwise have been treated as a dull subject. In the appendix then' is a section on "diagnostic problems at the boundary area between veterinary and human parasitology" that is an interesting discourse on the parasitic zoonoses. This is followed by some technical notes that compresses laboi-;itory technics to the point of l)eing reminder uotes. ^^'hat this book might lack in some definitive keys is compens.-ited by a great i)ro- fusion of excellent illustrations. The diagrammatic sketches are well done and these are supplemented by i)hotomicrography at its best. As might be expected from the foregoing, the ])hotomicrogra))hs jjrimarily cover the nematodes and assist in keying the arthropods. This volume will be a handy reference book when used in conjunc- tion with other texts.- .l/r//o(( A. Ronoi, Cdlifornid Depdrfnicnf of Fish and (iitmc. The Biologists Handbook of Pronunciafions liy Kdmuiid C Jaeger; Charles C. Th(». The octopus is a fascinating and mysterious denizen of the deep whose habits have been the subject of many colorful stories, both fact and fiction, since the time of Aristotle. The author has sifted the facts from an immense number of publica- tions, observations, travel diaries, ship logs and stories and condensed them iu read- able fashion. Liberal use of color and black and white plates add to the general interest of the book. All scientific terms have been translated into common terms familiar to everyone. The text has not been limited to the octopus but has space in each chapter devoted to the squid and cuttlefish ]ilus some ob.servations on the pearly nautilus. Chapter titles cover the standard life history functions plus fishing, economics, dangers and kraken. In the chapter on economics, reference is made to the drying of squid in California as the most important method of preservation. While this was true his- torically, today canning has completely replaced drying of squid. iLlO CALIFORNIA FISIL AND GAME Tiic1u(1(h1 in tlic iiiiiiciuliccs two a family troo. a systomatir list ^)f all roplialnpods im-iitioiieil in the toxt, list of coininon and sciontifio names iised, fjlossary of terms, and an extensive bihlioKraphy for each chapter. Mr. Lane shonld he commended for his style of writins, which extracts the meat from pnhlished articles and condenses it into a neat packa>;e easily swallowed by fishermen, skindivers. or tlie interested ))uhlic. The chapters on daiiRers and kraken are so interesting it is difiicult to put the book down until finished. — E. A. Best, California Department of Fixh