RICHARDSON and PEARCY: COASTAL ANDOCEANIC FISH LARVAE 



13 during August-December. Since samples were 

 taken only during 6 mo in 1972 and larval 

 abundances were greatly reduced, trends in 

 seasonality could not be assessed. 



In 1971, 42 taxa were taken in the February- 

 March period and 46 taxa were taken from May to 

 July. Of these, 10 occurred only during the winter 

 period, 14 occurred only in the spring, and 32 were 

 taken in both periods. Dominant taxa (with BI>1) 

 in the February-March period were P. vetulus (BI 

 = 4.09), Ammodytes hexapterus (BI = 1.76), /. 

 isolepis (BI = 1.73), and Osmeridae (BI = 1.51). 

 Together they made up 70% of the total larvae. 

 Parophrys vetulus alone accounted for 44%. 

 Dominant taxa from May to July 1971 were 

 Osmeridae (BI = 4.12), /. isolepis (BI = 2.21), M. 

 proximus (BI = 2.03), and Lyopsetta exilis (BI = 

 1.07). Together they made up 90% of the total 

 number of larvae in those months. Osmerids 

 accounted for 71% of the total in that period. 



Thus the two abundance peaks in 1971 were not 

 made up of completely different species. Some 

 were common to both (Table 6). Some species 

 occurred in the plankton collections during only a 

 few months. For example, Platichthys stellatus 

 larvae occurred over a restricted period of time 

 (Table 6), small larvae were taken only during a 

 few months mainly in spring, and they trans- 

 formed and settled out at a small size ( ~8 to 9 mm). 

 Hemilepidotus spinosus and A. hexapterus also 

 were taken during a short-time period, primarily 

 in winter. Larger A. hexapterus larvae avoid 

 plankton nets and may have been present for a 



longer period than the data suggested. On the 

 other hand, some species, such as Parophrys vetu- 

 lus andPsettichthys melanostictus, occurred over a 

 longtime period because of protracted spawning 

 seasons and relatively long planktonic life (Table 

 6). Parophrys vetulus spawned primarily from 

 January through March. Increases in larval 

 lengths indicated that spawning stopped and 

 larvae had settled out by July. Spawning began 

 again in September and continued at least 

 through December. Small larvae of Psettichthys 

 melanostictus were taken in most months except 

 July, August, and December. An increase in 

 modal length occurred from June through August 

 and again from September through November. 



Other species showed trends in seasonal oc- 

 currence somewhere between the two extremes. 

 Isopsetta isolepis apparently spawned from 

 February through May. Modal lengths increased 

 in successive months and large larvae were no 

 longer available to our gear by August. Micro- 

 gadus proximus also appeared to spawn from 

 February through June and the larvae were not 

 caught after August. Lyopsetta exilis apparently 

 spawned from March through June and larvae 

 were absent in collections from September 

 through February. Artedius sp. 1 and Artedius sp. 

 2 were taken over an 8-mo period and small larvae 

 occurred almost every month. Cottus asper was 

 taken from February through July, but larval 

 lengths showed no trends by month. Although 

 taxonomic problems exist with the osmerids, two 

 groups (possibly two species) were apparent from 



TABLE 6. — Ranges and modal lengths (mm) for dominant fish larvae in the coastal assemblage (stations 2-28) in 1971. Asterisks 

 indicate month in which average abundance per cruise was greatest. Parentheses are used where more than one modal peak occurred. 



135 



