COASTAL AND OCEANIC FISH LARVAE IN 

 AN AREA OF UPWELLING OFF YAQUINA BAY, OREGON 



Sally L. Richardson and William G. Pearcy 1 



ABSTRACT 



A 1%-yr survey of planktonic fish larvae collected from 2 to 111 km off the mid-Oregon coast in 

 1971-72 yielded 287 samples which contained 23,578 individuals in 90 taxonomic groups, 78 identified 

 at the species level. 



Two distinct faunal assemblages were found: a "coastal" assemblage 2 to 28 km offshore and an 

 "offshore" assemblage 37 to 111 km from shore. The coastal group was dominated by Osmeridae, 

 Parophrys vetulus, Isopsetta isolepis, and Microgadus proximus. The offshore group was dominated by 

 Sebastes spp., Stenobrachius leucopsarus, Tarletonbeania crenularis, Lyopsetta exilis, and Engraulis 

 mordax. Peak abundance in both assemblages occurred between February and July when >9(Wc of all 

 larvae were taken. Larval distribution patterns in each assemblage were similar in 1971 and 1972, but 

 larval abundance was greater in 1971 than 1972. 



Ninety-nine percent of the larvae in 53 taxa designated as coastal and 96% of the larvae in 31 taxa 

 designated as offshore were taken 2 to 28 km or 37 to 111 km offshore respectively. This separation of 

 coastal and offshore larvae may be explained, in part, by adult spawning locations and current 

 circulation patterns. 



The species of larvae present in the coastal assemblage were similar to those in Yaquina Bay, but 

 dominant species were quite different. The coastal zone is an important spawning area for P. vetulus, 

 which utilizes Yaquina Bay estuary as a nursery during part of its early life. 



In this paper, distribution patterns, seasonality, 

 species composition, dominance, and relative 

 abundance of larval fishes in an upwelling area off 

 Yaquina Bay, Oreg., are described. Included are 

 the most comprehensive time series of data yet 

 available on larval fishes in the northeast Pacific 

 Ocean north of California, data on the greatest 

 number of distinct larval taxa yet reported for this 

 area, and the first quantitative information on 

 coastal and offshore assemblages of larval fishes 

 off the northwest coast of the United States. 



Larval fish distributions are discussed in rela- 

 tion to current circulation patterns and spawning 

 location of adults. Results are compared with 

 Pearcy and Myers' (1974) study of larval fishes of 

 Yaquina Bay. The data on fish larvae are com- 

 pared with data on zooplankton (Peterson and 

 Miller 1975, footnote 2), shrimp larvae (Rothlis- 

 berg 1975), and crab larvae (Lough 1975) collected 

 at the same time and location. Distribution 

 patterns of larval fishes off the mid-Oregon coast 



'School of Oceanography, Oregon State University, Corvallis, 

 OR 97331. 



2 Peterson, W. T., and C. B. Miller. 1976. Zooplankton along the 

 continental shelf off Newport, Oreg., 1969-72: distribution, 

 abundance, seasonal cycle and year to year variations. Oreg. 

 State Univ. Sea Grant Coll. Prog. Publ. ORESU-T-76-002, 111 p. 



are discussed in relation to a broader geographic 

 area in the northeast Pacific. 



PREVIOUS STUDIES IN 

 THE NORTHEAST PACIFIC 



This review includes only studies of a general 

 survey nature conducted in ocean waters from 

 northern California to the Gulf of Alaska, 

 excluding the Aleutian Chain and Bering Sea. 

 Studies in sounds, bays, and estuaries are not 

 considered. 



Prior to 1972, data on ichthyoplankton in the 

 northeast Pacific were sparse and essentially 

 nonquantitative because of the gear used — 

 Isaacs-Kidd Midwater Trawls and Northern Pa- 

 cific area (NORPAC) nets (Motoda et al. 1957). 

 Surveys were designed primarily for biomass 

 estimates of pelagic invertebrates and fishes. The 

 ancillary data on fish larvae, often not identified to 

 species, were usually presented in the form of 

 appendix tables [Aron 3 for northern Washington 



Manuscript accepted September 1976. 

 FISHERY BULLETIN: VOL. 75, NO. 1, 1977. 



3 Aron, W. 1958. Preliminary report of midwater trawling 

 studies in the Pacific Ocean. Univ. Wash. Dep. Oceanogr. Tech. 

 Rep. 58, 64 p. 



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