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12 results on '"Hay, D.E."'

7. Population dynamics and stock assessment of common kilka (Clupeonella cultriventris caspia) in Iranian waters of the Caspian Sea

Author

Fazli, H., Zhang, C.I., Hay, D.E., Lee, C.W., Janbaz, A.A., and Bourani, M.S.

Subjects
Clupeonella cultriventris caspia, Fisheries, Stock assessment, Caspian Sea, Growth, Iran, Biology, Maturity stages
Abstract

This paper examines the changes in the population biology and biomass of common kilka (Clupeonella cultriventris caspia) in the Iranian waters of the Caspian Sea from 1995-2004. For most years during this 10-year period, we estimated the age structure of the catch, length-weight relationship, von Bertalanffy growth parameters, condition factor, sex ratios, maturity stages determined from ovarian analysis, natural and fishing mortality, age at first capture and biomass. Growth parameters were estimated as L∞=132mm, K=0.259/yr, t0=-1.285/yr. The instantaneous coefficient of natural mortality was estimated at 0.506/yr and the instantaneous coefficient of fishing mortality varied during the 10-year period between 0.125/yr to 1.487/yr. Biomass of the common kilka increased from about 16,000mt in 1995 to more than 41,000mt in year of 2002. This increase in common kilka was simultaneous with a sharp decline in anchovy kilka, changes in zooplankton abundance and composition, and especially increase in zooplankton species used by common kilka. We concluded that at the present time, the stock of common kilka is being over-fished.

Published
2007

9. Tagging along: association among individual Pacific herring (Clupea pallasi) revealed by tagging.

Author

Hay, D.E. and McKinnell, S.M.

Subjects
*ATLANTIC herring, *FISH tagging, *FISHERY management, *FISH industry, *AQUATIC resources
Abstract

More than 570 000 Pacific herring (Clupea pallasi) were tagged with external anchor tags during 429 tag release sessions between 1979 and 1992. Individually numbered tags were released in quantities of 1000-2000 at a time and recovered from commercial fisheries. Often several tags were recovered at the same time and place, and some recoveries occurred as "matches", where two or more tags from a single release session were recovered together. We tested the hypothesis that the frequency of matching tag recoveries occurred by chance through random mixing of tagged herring before their recapture during fishing operations. The alternative is nonrandom, positive association among tagged individuals that persisted through time and during migrations. We used a statistical method developed to address a similar question in steelhead trout (Oncorhynchus mykiss). In separate tests, we examined tag recovery data from migratory stocks in five major regions of the British Columbia. The results indicate nonrandom association of herring for periods of 6 months to several years and through migrations over considerable distances. [ABSTRACT FROM AUTHOR]

Published
2002
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10. Tagging of Pacific herring Clupea pallasi from 1936-1992: a review with comments on homing, geographic fidelity, and straying.

Author

Hay, D.E., McCarter, P.B., and Daniel, K.S.

Subjects
*ATLANTIC herring, *FISH tagging
Abstract

Reports on the results of tagging experiments of Pacific herring (Clupea pallasi), conducted from 1936 and 1992 in British Columbia. Homing, geographic fidelity, and straying; Distribution of spawning sites in B.C. herring; Description of herring tagging projects in B.C.; Estimation of the number of years-at-large.

Published
2001
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