Ichthyoplankton Composition and Plankton Volumes 

 From Inland Coastal Waters of Southeastern Alaska, 



April-November 1972 



CHESTER R. MATTSON AND BRUCE L. WING' 

 ABSTRACT 



Eighteen families of flsh were represented in 119 plankton samples taken on monthly cruises from 

 April to November 1972 in southeastern Alaska. Fifteen kinds of larval fish were identified to species. 

 Abundance of larval fish, fish eggs, and total plankton biomass peaked in May and declined through 

 the summer. Walleye pollock (family Gadidae) were the most abundant larvae in May and June and 

 were more concentrated in large channels than in small bays. Osmeridae and Bathylagidae were the 

 second and third most abundantly represented families; peak abundance for both was in June and 

 July. Other families with distinct peaks in abundance were Agonidae and Ammodytidae in May; Cot- 

 tidae, Cyclopteridae, Stichaeidae, and Pleurnnectidae in June; and Scorpaenidae in July. Small num- 

 bers of Bathymasteridae were present from May through July. Myctophidae, Zoarcidae, and Hex- 

 agrammidae did not show distinct changes in seasonal abundance. Clupeidae, Gasterosteidae, 

 Pholidae, and Ptilichthyidae were too rare in the catches to exhibit seasonal abundance. Calanoid 

 copepods and phytoplankton made up most of the plankton retained by 0.333-mm mesh nets. 



INTRODUCTION 



This report presents data on the kinds, distribution, 

 and numerical abundance of ichthyoplankton and on 

 total net plankton biomass in northern southeastern 

 Alaska. The data are from an 8-mo study, April-Novem- 

 ber 1972. The study was intended to develop sampling 

 methods, schedules, and station patterns for routine sur- 

 veys in Alaska coastal waters. The stations represented 

 three basic types of marine environment in southeastern 

 Alaska — enclosed bays, middle of deep channels, and the 

 margin, or edge, of channels. Stations were grouped from 

 north to south so that differences in species distribution 

 and abundance within and between geographical and en- 

 vironmental areas could be evaluated. Funding and 

 manpower restrictions imposed after completion of the 

 field work have limited sample analyses to one sample 

 per station per month (approximately one quarter of the 

 samples taken). The data have not been subjected to in- 

 tensive interpretative analyses but are presented here in 

 preliminary form to make them available to other 

 workers, because published ichthyoplankton data for the 

 area are limited to the small amount in Wing and Fteid 

 (1972) for Auke Bay. 



METHODS 



Eight monthly cruises, extending from April into 

 November 1972, were made aboard the MV Murre II. 



The first cruise, 10-14 April, was a test to determine how 

 many stations could be occupied in a week. As a result, a 

 total of 21 stations were selected that could be sampled 

 in 2-wk cruises (Table 1); five of the original April 

 stations were deleted and replaced by others more con- 

 venient to cruise routing (Fig. 1). A northern cruise, con- 



Table I. --Location, bottom depth at station, proposed sas^lJLng depth, and habitat 

 category of plankton stations routinely oco^iied in southeastern Alaska, Af>ril-Noved>er 

 1972. (6 ■ Bay, C " midchannel, E - margin of channel). 



'Northwest and Alaska Fisheries Center Auke Bay Laboratory, Na- 

 tional Marine Fisheries Service, NOAA, P.O. Box 155. Auke Bay. AK 

 99821. 



