29.12.2013 Views

Vol. 53 - Alaska Resources Library and Information Services

Vol. 53 - Alaska Resources Library and Information Services

Vol. 53 - Alaska Resources Library and Information Services

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

3.7 Epibenthic Associations<br />

A variety of fish <strong>and</strong> invertebrate species was collected <strong>and</strong> enumerated<br />

in trynet <strong>and</strong> rock dredge samples. A general picture of distributional<br />

patterns of species groups, or associations, can be derived from the<br />

collection data. Trynet samples provided a more reliable quantitative<br />

data set due to the efficiency of the sampling gear on the bottom types<br />

sampled. The rock dredge data were much less reliable, <strong>and</strong> many rock<br />

dredge hauls were treated qualitatively.<br />

Trynet biomass data, expressed as mean catch per unit effort (CPUE,<br />

g m- 2 ), were used to assess the relative importance of major taxonomic<br />

groups (Table 3.7-1). Trynet samples were dominated by pleuronectids,<br />

asteroids <strong>and</strong> ascidians. The pleuronectids were represented<br />

primarily by yellowfin sole (Lim<strong>and</strong>a aspera) <strong>and</strong> rock sole (Lepidopsetta<br />

bilineata), the asteroids were primarily Asterias amurensis, <strong>and</strong> the<br />

ascidians were almost all Boltenia ovifera. Pleuronectids ranged from<br />

41 to 51 percent, asteroids from 18 to 33 percent, <strong>and</strong> ascidians from<br />

3.3 to 7.7 percent of the total mean CPUE per cruise. These three<br />

groups combined ranged from 72.7 to 85.3 percent of the total mean CPUE<br />

per cruise.<br />

Fish taxa of secondary importance in trynet samples included the<br />

codfishes (Gadidae) <strong>and</strong> sculpins (Cottidae); these groups accounted for<br />

from 3 to 13 percent of fish mean CPUE (% catch) per cruise, <strong>and</strong> from 2<br />

to 8 percent of the total mean CPUE (% total) per cruise. Invertebrate<br />

taxa of secondary importance included the s<strong>and</strong> dollar, Echinarachnius<br />

parma (Echinoidea), sponge (Porifera), red king crab (Paralithodes) <strong>and</strong><br />

crangon shrimps (Crangonidae). Marine tube-building worms (Polychaeta)<br />

were important in the April-May samples.<br />

The total mean CPUE for trynet samples increased from 5.6 g m -² during<br />

the April-May cruise to 15.4 gm -² during June <strong>and</strong> 17.40 g m -² during<br />

September. These increases were largely a result of greater flatfish<br />

<strong>and</strong> sea star catches during the latter two cruises (Table 3.7-1).<br />

375

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!