Study of the biology and distribution of Pacific hake during the first commercial fishery conducted in the Strait of Georgia by the M/V Callistratus February 16-17, March 10-April 3, and May 12, 1979 /... : Fs97-4/1650E-PDF

"Catch statistics, by species and biological data, for important species, were collected for midwater trawl sets of the stern-ramp trawler CALLISTRATUS in Georgia Strait during February, March, and May 1979. A total of 79 sets were completed--three in February, 75 in March, and one in May. Eleven species were identified in the catches. Principal species was Pacific hake (Merluccius productus) and secondary species were walleye pollock (Theragra chalcogramma) and spiny dogfish (Squalus acanthias). Pacific hake ranged in length from 9-67 cm and age from 1-18 yr. Principal age groups were 4-9 yr. Age-1 and age-2 hake had length frequency modes at 11 and 22-23 cm, respectively. Age-3 hake had a mean length of 33.3 cm as determined from length at age plots. Length at age plots show rapid growth to age-4 and a subsequent reduction in growth of older fish. Maturity studies in the central Strait during March-April indicated males were in a more advanced state of maturity and predominated (84%) in the catch. In May, after peak spawning, males represented 45% of the catch. Age composition using otolith sections indicated annual total mortality rates of A=0.53 (Z=0.74) and A=0.59 (Z=0.88) for males plus females for age groups 5-7 and 8-11, respectively. Food items of hake sampled consisted entirely of fish or partially digested hake and shrimp. Walleye pollock ranged in length from 30-58 cm. Males predominated in all catches (170-220 m), and no females were caught deeper than 200m. All pollock sampled were mature"--Abstract, page iii.

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