604 



Fishery Bulletin 93(4), 1995 



June, no data are available on the distribution and 

 abundance patterns of late larval or early juvenile 

 T. chalcogramma during mid-summer, when they are 

 at a size that makes them vulnerable to plankton 

 gear. Moreover, little is known about the relation- 

 ship of T. chalcogramma distribution to that of the 

 other common ichthyoplankton taxa that are caught 

 with the same type of gear. Our aim in this study 

 was to examine the large-scale distribution patterns 

 of age-0 T. chalcogramma and their associations with 

 other larval and juvenile fishes. We also estimate for 

 the first time the relative abundance of age-0 T. 

 chalcogramma compared with other co-occurring 

 early life history stages of marine fish taxa present 

 during mid-summer on the continental shelf in the 

 western Gulf of Alaska. 



Miller Freeman from 23 to 31 July 1991 (Dewitt and 

 Clark 1 ). The Methot trawl was selected as the most 

 appropriate sampling gear for this stage of 

 T. chalcogramma life history on the basis of previ- 

 ous gear comparisons (Shima and Bailey, 1994). The 

 5-m 2 rigid frame trawl (2x3 mm oval mesh) is de- 

 signed to sample micronekton that evade smaller 

 plankton nets and that pass through the mesh of 

 larger trawls (Methot, 1986). A grid of stations per- 

 pendicular to the coast along the Alaska Peninsula 

 was occupied (Fig. 1) and 61 successful Methot trawls 

 were completed (39 day and 22 night), with repeat 

 tows at several stations. All tows were made at an 

 average ship speed of 6 km-h" 1 and in a double ob- 

 lique pattern to within 10-20 m of the bottom. Tem- 

 perature profiles were taken at each station by us- 

 ing expendable bathythermographs. 



Methods 



A FOCI survey of late larval and early juvenile T. 

 chalcogramma was conducted aboard the NOAA ship 



1 Dewitt, C, and J. Clark. 1993. Fisheries Oceanography Coor- 

 dinated Investigations: 1991 field operations report. NOAA 

 Data Rep. ERL PMEL-41, 112 p. 



-57°N 



yM, + + + + 



Shumagin Islands 



^ r ; + + + + 



Sanak Island 



Gulf of Alaska 



166°W 



164° 



~~ I — 

 162° 



- 1 — 

 160° 



56° 



-55° 



54° 



-53° 



158° 



156° 



Figure 1 



Grid stations sampled during July 1991 with the Methot trawl and location of study area within the 

 North Pacific Ocean (inset). 



