MIDWATER ASSESSMENT AND CONSERVATION ENGINEERING (MACE) PROGRAM:
Preliminary Results of the Gulf of Alaska EIT Pollock Survey (cont.)
Pollock was the most abundant species caught in midwater trawl hauls, comprising
82.3% and 51.8% of the total catch by weight and numbers, respectively.
In bottom trawls, several of which were conducted in midwater, Pacific
ocean perch was the most abundant species caught, accounting for 46.6%
by weight and 44.4% by numbers. Pollock was the next most abundant species
caught by weight (21.6%). Capelin was the only species caught in the single
Marinovich trawl haul. Most pollock echosign was detected in the vicinity
of Kodiak Island in Barnabas and Chiniak Troughs, in the Shelikof Strait
sea valley, and Marmot and Alitak Bays (Fig. 2 above). Pollock were also concentrated
in near-shore basins of deep water off Renshaw Point in the Shumagin Islands
and off Nakchamik Island. Diffuse midwater layers of pollock were occasionally
observed along the shelf break between about 300- and 500-m bottom depths.
Virtually no pollock echosign was detected over bottom depths less than
100 m except in Alitak Bay, where fish were detected just outside the mouth
of the bay over bottom depths of 60-70 m. Pollock were usually observed
in aggregations within 20 m of the seafloor or as discrete schools located
throughout the water column during daylight hours and tended to disperse
throughout the water column at night.
In addition to the EIT survey work, a marine mammal sighting survey was
conducted by National Marine Mammal Laboratory (NMML) scientists along
the eastern EIT survey track (see NMMLs Cetacean Assessment and Ecology
Program report in this issue).
By Sarah Stienessen.
Trawl Modifications To Reduce Salmon Bycatch In Pollock Trawls
RACE division scientists teamed up with industry specialists to study ways
to reduce salmon bycatch in trawl fisheries for pollock. During the first
2 weeks of September video recordings and sonar observations were made
of pollock and salmon behavior using the Vesteraalen. The observations
were used to improve several modifications allowing salmon escapes and
to select one for subsequent testing.
From 13 to 19 September, the bycatch reduction device was tested under
an exempted fishing permit aboard the F/V Auriga. Full-scale pollock trawling
was conducted using modified trawl with an auxiliary recapture net to enumerate
the number of escaping fish. Preliminary results indicate that salmon
bycatch was reduced by approximately 12% with less than 2% loss of the
targeted pollock. Development and testing will be continued during trials
in the winter pollock fishery in January.
By Craig Rose.
The fall Recruitment Processes cruise was conducted aboard the Miller Freeman
during 7-21 September 2003. The cruise was designed to address biological
and methodological questions regarding juvenile walleye pollock and other
forage fishes in the western Gulf of Alaska.
By Kevin Bailey.
Staff Volunteer at Fishermens Festival
RACE and REFM staff members Bob Lauth, Chris Wilson, Sarah Gaichas, Lyle
Britt, Jerry Hoff, Ned Laman, Steve Barbeaux, Eric Brown, Rachel Cartwright,
Gary Stauffer, and Mark Wilkins each spent Saturday, 13 September, at the
Fishermens Fall Festival at Fishermens Terminal in Seattle, Washington,
displaying examples of groundfish species to the festival-goers. For several
years the AFSC has teamed with the Deep Sea Fishermens Union to bring
real fish to the festival. The Centers booth has been one of the more
popular at the event and gives staff a chance to introduce the public to
what groundfish are, and to answer questions about the fish and our work
to monitor and manage the stocks.
quarterly July-Sept 2003 sidebar
Auke Bay Lab