Literature Cited 



Baraclough, W. E. 



1967. Number, size and food of larval and juvenile fish caught 

 with a two-boat surface trawl in the Strait of Georgia, April 

 25-29, 1966. Fish. Res. Board Can., Biol. Stn. Nanaimo, 

 B.C., Manuscr. Rep. Ser. 922, 54 p. 

 Mason, J. C, R. J. Beamish, and G. A. McFarlane. 



1983. Sexual maturity, fecundity, spawning, and early life 

 history of sablefish (Anoplopoma fimbria) off the Pacific 

 coast of Canada. Can. J. Fish. Aquat. Sci. 40:2126-2134. 

 Sameoto, D. D., and L. 0. Jaroszynski. 



1969. Otter surface sampler: a new neuston net. J. Fish. 

 Res. Board Can. 26:2240-2244. 



J. C. Mason 

 A. C. Phillips 



Pacific Biological Station 

 Fisheries Research Branch 

 Department of Fisheries and Oceans 

 Nanaimo, British Columbia V9R 5K6, Canada 



MORPHOLOGICAL EVIDENCE FOR 



STARVATION AND PREY SIZE SELECTION 



OF SEA-CAUGHT LARVAL SABLEFISH, 



ANOPLOPOMA FIMBRIA 



One of the major causes of larval mortality is star- 

 vation, this being related to the patchiness of food 

 resources (Hunter 1981). While starvation has been 

 induced under laboratory conditions [e.g., herring, 

 Clupea harengus, and plaice, Pleuronectes platessa 

 (Ehrlich et al. 1976); northern anchovy, Engraulis 

 mordax (O'Connell 1976); jack mackerel, Trachurus 

 symmetricus (Theilacker 1978, 1981)], starved lar- 

 vae have rarely been observed in nature (northern 

 anchovy, O'Connell 1980; jack mackerel, Theilacker 

 1986). Various methods have been used to charac- 

 terize starvation in fish larvae, including condition 

 factor (Blaxter 1971), chemical analyses (Ehrlich 

 1974), histological analyses (Umeda and Ochiai 1975; 

 O'Connell 1976, 1980; Theilacker 1978, 1986), and 

 morphological analyses (Shelbourne 1957; Nakai et 

 al. 1969; Ehrlich etal. 1976; Theilacker 1978, 1981, 

 1986). While histological and chemical analyses are 

 based on qualitative changes in tissues that result 

 from starvation, their methodologies require special 

 preservation techniques, negating their application 

 to samples preserved without these techniques in 

 mind. To characterize starvation in samples that 

 have not been specially preserved, measures of mor- 

 phology and/or condition factor are more appropri- 



ately applied. In the present study, in the absence 

 of special preservation techniques, the occurrence 

 of starvation in sea-caught larval sablefish, Anoplo- 

 poma fimbria, was examined using morphological 

 measures. 



The sablefish inhabits the continental shelf of the 

 North Pacific Ocean and is the subject of an inten- 

 sifying fishery off the west coast of North America, 

 yet little is known about the early life history of the 

 species. Recent evidence obtained off Canada sug- 

 gests that sablefish spawn in water deeper than 300 

 m, with spawning activity peaking in February. 

 Eggs (1.8-2.2 mm in diameter) descend while devel- 

 oping, and hatching probably occurs at depths in ex- 

 cess of 400 m (Mason et al. 1983). Although size at 

 hatching and the size at first feeding have not been 

 clearly defined, Mason et al. (1983) reported collect- 

 ing recently hatched larvae of 5-6 mm. After hatch- 

 ing, larvae ascend to surface waters and become 

 neustonic (Kendall and Clark 1982 1 ). Juveniles ap- 

 parently remain in shallow water until they mature. 

 Beyond reports of distribution (Kendall and Clark 

 fn. 1; Clark 1984 2 ) and descriptive work (e.g., Koba- 

 yashi 1957; Ahlstrom and Stevens 1976), studies of 

 larval and early juvenile sablefish have concentrated 

 on aging and growth (Boehlert and Yoklavich 1985; 

 Shenker and Olla in press). 



Our aim in the present study was to detect the 

 possible occurrence of starvation in larval sablefish 

 collected off Washington and Oregon during April 

 and May 1980 (Kendall and Clark fn. 1), using 

 selected morphological measurements to determine 

 variability in larval condition. Further, to elucidate 

 the possible relationship between larval condition 

 and feeding requirements, prey size-selection and 

 diet were analyzed. 



Methods 



Sablefish larvae were collected by using a 0.5 m 

 neuston net (Sameoto and Jaroszynski 1969) with 

 0.505 mm mesh, towed for 10 min from the RV 

 Tikhookaenskiy , during the first cooperative U.S.- 

 U.S.S.R. ichthyoplankton survey off the Washing- 

 ton and Oregon coast in 1980 (Kendall and Clark 

 fn. 1). Larvae from stations 20, 24, 25, 34, 38, 50, 



Kendall, A. W., and J. Clark. 1982. Ichthyoplankton off 

 Washington, Oregon and Northern California, April-May 1980. 

 Processed Rep. 82-11, 44 p. Northwest and Alaska Fisheries 

 Center, National Marine Fisheries Service, NOAA, Seattle, WA 

 98112. 



2 Clark, J. B. 1984. Ichthyoplankton off Washington, Oregon 

 and Northern California, May-June 1981. Processed Rep. 84-11, 

 46 p. Northwest and Alaska Fisheries Center, National Marine 

 Fisheries Service, NOAA, Seattle, WA 98112. 



484 



FISHERY BULLETIN: VOL. 84, NO. 2, 1986. 



