Larval Fish Survey of Humboldt Bay, California 



By 

 MAXWELL B. ELDRIDGE 



National Marine Fisheries Service 



Tiburon Fisheries Laboratory 



Tiburon, CA 94920 



and 



CHARLES F. BRYAN 



Cooperative Fisheries Unit 



Louisiana State University 



Baton Rouge, LA 70803 



ABSTRACT 



As part of a series of investigations of the marine resources of Humboldt Bay, 

 Calif., a larval fish survey was conducted from January to December 1969. Bottom and 

 oblique tows were made at five sampling stations with 1-m plankton nets on alternate 

 biweekly intervals. Thirty-seven species of larval and juvenile fishes representing 17 

 families were collected. In terms of larval abundance, the dominant fish was the bay 

 goby, Lepidogobius lepidus, followed by Pacific herring (Clupea harengus pallasi). 

 Pacific staghorn sculpin (Leptocottus armatus), longtin smelt (Spirinchus thaleichthys), 

 and the arrow goby {Clerelandia ios). These five species constituted 95% of all larvae 

 captured. 



The number of larvae captured increased with increasing distance from the mouth 

 of the Bay. The lowest number of species captured was at a station which experienced 

 the widest range of salinities and temperatures. Peaks of seasonal abundance occurred 

 in January and February and in April and May. Relatively few fish were captured 

 after June. Some notable appearances of offshore spawned fishes were found in Hum- 

 boldt Bay. 



INTRODUCTION 



Pacific coast estuaries are important spawn- 

 ing and nursery grounds for fishes, but the 

 extent of this utilization has received little 

 attention from fishery scientists. In northern 

 California waters, several biologists have 

 conducted investigations. Porter (1964) studied 

 the larval and juvenile pleuronectids and 

 bothids in the waters adjacent to the entrance 

 of Humboldt Bay, Calif. Further pleuronectid 

 research was carried on when Misitano (1970) 

 captured premetamorphosed and juvenile 



English sole (Parophrys vetulus) during the 

 course of his early life history study. Some 

 incidental catches of fish larvae were made in 

 a zooplankton survey recently completed in 

 the northern part of Humboldt Bay (Eichen- 

 berry, 1970). The most current research in- 

 volves a larval cottid study which was begun 

 in the spring of 1971. 



This larval fish survey was conducted as 

 part of a series of studies to evaluate the 

 resources of Humboldt Bay. From January 

 to December 1969, an intensive effort was 



