FISHERY BULLETIN: VOL. 87. NO. 4, 1989 



certain shallow-water species (Larson 1980; 

 Hallacher and Roberts 1985). 



Heceta Bank, and probably other rocky banks 

 off the Pacific Northwest and Southeast Alaska, 

 appear to be important juvenile nursery areas 

 for rockfishes. Dense schools of pelagic juveniles 

 and adult yellowtail rockfishes were observed 

 only over the rocky, high-relief areas on the top 

 of the bank, and high densities of benthic juve- 

 niles were found only on the flanks of the bank 

 and not in deeper waters of the bank (Table 2). 

 Straty (1987) and Carlson and Straty (1981) ob- 

 served large schools of young rockfish near 

 rocky pinnacles and boulder fields at depths 

 <171 m off southeastern Alaska, and concluded 

 that these areas were nursery grounds for rock- 

 fish. They collected specimens of Pacific ocean 

 perch, S. alutus; sharpchin, pygmy, and Puget 

 Sound rockfishes; and shortspine thornyheads on 

 the bottom, species (with the exception of S. 

 alutus) that we captured on Heceta Bank (Table 

 3). 



Some of our submersible dives were close to 



locations previously sampled by trawl surveys of 

 the Oregon Department of Fish and Wildlife 

 (ODFW) (Barss et al. 1982). In the ODFW sur- 

 veys, commercial trawls designed for catching 

 rockfishes on rough terrain (Atlantic Western 

 and Box Mystic trawls) were used with roller 

 gear to keep the footrope off the bottom. The cod 

 end of these nets was usually made of 11.4 cm 

 mesh. During 1980-81, a total of 27 tows were 

 made between 132 and 210 m, within about 4 km 

 of Dive Site 11 (145 m) (Fig. 2). 



Fish assemblages in trawl catches and in sub- 

 mersible observations from adjacent areas dif- 

 fered. Only 8 of the 25 trawl-caught species were 

 seen from the submersible on Dive 11, and 7 of 

 the species observed during the dive were not 

 caught in trawls (Table 4). Five species of rock- 

 fishes, however, were among the most numerous 

 11 species by both methods. Sebastes pinniger 

 dominated trawl catches by number and weight 

 (comprising 88% of the total weight of the 

 catches), but it was not seen many times from 

 the submersible. 



Table 4. — Composition of fishes by percentage calculated from numbers 

 during submersible dives and caugfit in trawls from the same general area 

 near Heceta Bank. The weight of individual species caught in trawl catches 

 were converted to numbers of a species by dividing by the average weight of 

 individuals. 



Dive 1 1 



Bottom trawl 



% 



Species 



% 



Species 



30.1 Schooling Sebastes spp. 

 29.4 Sebastes helvomaculatus 

 10.7 Sebastes unidentified 



7.2 Sebastes zacentrus 



4.6 Sebastes pinniger 



4.2 Sebastes ruberrimus 



4.2 Zoarcidae 



1.5 Sebastes crameri 



1.1 Rajidae 



1 . 1 Sebastes diploproa 



1 . 1 Raja rtiina 



0.8 Hexagrammos decagrammus 



0.8 Raja binoculata 



0.4 Sebastes elongatus 



0.4 Ophiodon elongatus 



0.4 Cottidae 



0.4 Sebastes nigrocinctus 



0.4 Sebastes saxicola 



0.4 Eptatretus stouti 



0.4 Agonidae 



0.4 Glyptoceptialus zachirus 



76.2 Sebaster pinniger 



10.1 Sebastes zacentrus 



2.5 Sebastes flavidus 



2.1 Sebastes hielvomaculatus 

 1.5 Merluccius productus 



1 .2 Ophiodon elongatus 

 1.2 Sebastes jordani 



1 .0 Sebastes elongatus 



1.0 Sebastes proriger 



0.6 Sebastes brevispinnis 



0.4 Squalus acanttiias 



0.4 Anoplopoma fimbria 



0.4 Trachurus symmetricus 



0.3 Hydrolagus colliei 



0.2 Sebastes ruberrimus 



0.2 Sebastes paucispinis 



0.2 Microstopmus pacificus 



0.1 Hippoglossus stenolepis 



0. 1 Parophrys vetulus 



0.1 Glyptoceptialus zachirus 



0.1 Sebastes entomelas 



<0.1 Oncorhynchus tshawytscha 



<0.1 Eopsetta jordani 



<0.1 Raja rhina 



<0.1 Atheresthes stomias 



964 



