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The growth and mortality of larval herring, Clupea harengus L., in the River Blackwater Estuary, 1978–1980
Author(s) -
Henderson P. A.,
Whitehouse J. W.,
Cartwright G. H.
Publication year - 1984
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1984.tb04832.x
Subject(s) - estuary , biology , herring , clupea , larva , blackwater , yolk sac , fishery , population , fishing , zoology , ecology , fish <actinopterygii> , demography , embryo , environmental engineering , sociology , engineering
Herring larvae were sampled in the Outer Thames Estuary and the River Blackwater Estuary in the springs of 1978, 1979 and 1980. Data were collected on larval stage, yolk sac and post yolk sac, larval length and total larval numbers. Newly hatched larvae were 6.8±0.5 mm long and the growth rate of yolk sac larvae was estimated at 0.18 mm d −1 ( L = 6.8±0.186 t ). The growth rate of post yolk sac larvae increased to 0.43mm d −1 ( L = 11±48.0±43 t ). Mortality estimates, derived from total numbers in the summed estuary segments, varied between the years and the cohorts within the year. In 1979 the mortality rates were 0.061 d −1 and 0.074 d −1 for the two cohorts. The mean size of the larval population was estimated at 2.48×10 9 (1.63–3.77 × 10 9 ) which agreed well with population size estimates from egg laying and from catch in numbers at age together with estimated fishing mortality rates.