ABUNDANCE AND DISTRIBUTION OF LARVAL FISHES IN WATERS 



OFF OREGON, MAY-OCTOBER 1969, WITH SPECIAL EMPHASIS 



ON THE NORTHERN ANCHOVY, ENGRAULIS MORDAX 



Sally L. Richardson* 



ABSTRACT 



Quantitative information on larval fishes in waters off Oregon is presented. Three hundred 

 fifty-four samples, containing 55,049 larvae, were taken from lat. 42°00' to 46°30'N and 

 from the coastline to long. 129°30'W during six cruises, May to October 1969. Catches by 

 three types of gear — bongos, meter net, and Isaacs-Kidd midwater trawl — are compared. 

 The midwater trawl captured the greatest number of taxa and had the greatest frequency of 

 occurrence of major taxa while overall the bongos caught the most larvae per 1,000 m^ of 

 water filtered. Shallow tows compared with deep tows from the same stations showed small 

 anchovy larvae were concentrated near the surface while larvae of myctophids and scor- 

 paenids were more common in deeper waters. 



Species composition (40 taxa in 22 families from deep tows), frequency of occurrence, 

 abundance, and dominance are discussed. Northern anchovy, Engraulis mordax; northern 

 lampfish, Sienobrachius leucopsarus; blue lanternfish, Tarletonbeania crenularis, and Sebastes 

 spp. were the most dominant taxa. Distributional features of species in the most important 

 families are described. E. mordax larvae were concentrated in Columbia River plume waters 

 from June to August. 



Species composition, abundance, seasonal occur- 

 rence, and areal distribution of larval fishes in 

 ocean waters of the northeast Pacific off Oregon 

 are virtually unknown (Ahlstrom, 1968). Pearcy 

 (1962)2 and LeBrasseur (1970)3 Usted larval 

 fishes from these waters collected only inciden- 

 tally to major sampling goals. Waldron (1972) 

 provided the first quantiative data on larvae off 

 Oregon collected from 12 April to 11 May 1967. 

 No additional comprehensive, quantitative 

 information has been published. 



From 10 May to 31 October 1969, the Depart- 

 ment of Oceanography of Oregon State Univer- 

 sity conducted a series of cruises off Oregon to 

 quantitatively study the chemical, physical, 

 and biological interrelationships involved with 



two major oceanographic phenomena — the 

 Columbia River plume and coastal upwelling. 

 The area surveyed extended from lat. 42°00' 

 to 46°30'N and from the coastline to long. 

 129°30'W. 



This extensive sampling effort yielded much 

 quantitative information on abundance and 

 distribution of larval fishes off Oregon. Three 

 types of gear are compared for their effective- 

 ness in catching fish larvae. Shallow tows are 

 compared with deep tows made at the same 

 stations on two cruises. Species composition, 

 frequency of occurrence, abundance, and domi- 

 nance are discussed. Occurrence and distribu- 

 tion patterns are described for species in the 

 most important families. 



' School of Oceanography, Oregon State University, 

 Corvallis, OR 97331. 



2 Pearcy, W. G. 1962. Species composition and distri- 

 bution of marine nekton in the Pacific Ocean off Oregon. 

 Oreg. State Univ., Dep. Oceanogr., A.E.C. Prog. Rep. 1, 

 Ref. 62-8, 14 p. (Unpubl. manuscr.) 



3 LeBrasseur, R. 1970. Larval fish species collected in 

 zooplankton samples from the northeastern Pacific Ocean, 

 1956-1959. Fish. Res. Board Can., Tech. Rep. 175, 47 p. 



Manuscript accepted February 1973. 

 FISHERY BULLETIN: VOL. 71, NO. 3, 1973. 



MATERIALS AND METHODS 



Six cruises were conducted at approximately 

 monthly intervals from 10 May to 31 October 

 1969 in waters off Oregon. Inclusive cruise 

 dates and stations occupied during these cruises 

 are shown in Figure 1. 



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