00000nam 2200000zi 4500 9.950140 CaOODSP 20250415081755 m o d f cr mn||||||||| 250415e198612##bccab ob f000 0 eng d CaOODSP eng rda CaOODSP eng eng fre n-cn-bc n-us-ak pn----- x6x8 Fs97-6/1510E-PDF Fs97-6/1510E Leaman, B. M., 1949- author. Biomass survey of rockfish stocks in the Dixon Entrance-southeast Alaska region, July 5-22, 1983 (R/V G.B. Reed and M/V Free Enterprise No. 1) / by B.M. Leaman and D.A. Nagtegaal. Nanaimo, British Columbia : Department of Fisheries and Oceans, Fisheries Research Branch, Pacific Biological Station, December 1986. ©1986 1 online resource (iv, 63 pages) : illustrations, maps. text txt rdacontent computer c rdamedia online resource cr rdacarrier Canadian technical report of fisheries and aquatic sciences, 0706-6457 ; no. 1510 Digitized edition from print [produced by Department of Fisheries and Oceans]. Includes bibliographical references (pages 9-10). "Two vessels were used to survey rockfish aggregations on the outer continental shelf (180-640 m) between 54°10'N - 55°30'N, using echo sounder and bottom trawl gear. Both stratified-systematic and encounter-response search patterns were employed to detect and map significant aggregations. Rockfish density in the survey area was very low with only two areas showing extensive rockfish echo soundings. One large aggregation (~9 M² ) was observed near 55°10'N and a second area of higher density was detected between 54°10' - 54°25'N. No estimation of the biomass in the northern aggregation was possible due to rough bottom. Individual schools in the southern area were mapped and sampled. Extrapolation of catch rates over school dimensions suggests a minimum biomass of ~1200 t ± 67%, composed primarily (89%) of Sebastes alutus. Catch rates ranged from 1000-16,000 kg/h. Biomass estimates for comparable areas of a 1979 survey showed both major and minor decreases over the 1979 estimates, depending on area. In addition the commercial fishery has removed approximately four times the total 1983 estimate, during the 1983-1985 period. The value of swept-area surveys for rockfishes is reviewed in light of these results"--Abstract, page iii. Includes abstracts in English and French. Sebastes Dixon Entrance (B.C. and Alaska) Sebastes fisheries Dixon Entrance (B.C. and Alaska) Fish populations Estimates Dixon Entrance (B.C. and Alaska) Fish surveys Dixon Entrance (B.C. and Alaska) Sébastes Dixon, Détroit de (C.-B. et Alaska) Sébastes Pêche commerciale Dixon, Détroit de (C.-B. et Alaska) Poissons Populations Estimation Dixon, Détroit de (C.-B. et Alaska) Inventaires ichtyologiques Dixon, Détroit de (C.-B. et Alaska) Canada. Department of Fisheries and Oceans, issuing body. Pacific Biological Station (1972- ), issuing body. Canadian technical report of fisheries and aquatic sciences ; no. 1510. (CaOODSP)9.504449 PDF 1.46 MB https://publications.gc.ca/collections/collection_2025/mpo-dfo/fs97-6/Fs97-6-1510-eng.pdf