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The influence of growth rate on the size of migrating female eels in Lake Ellesmere, New Zealand
Author(s) -
Jellyman D. J.
Publication year - 2001
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.1095-8649.2001.tb00525.x
Subject(s) - biology , fecundity , growth rate , fishery , population , ecology , zoology , demography , geometry , mathematics , sociology
Lake Ellesmere, a large coastal lake in the South Island of New Zealand, supports an important commercial eel fishery, based mainly on migrating (silver) male Anguilla australis . Lengths of silver female eels from samples collected in 1942, 1974–1982 and 1998–1999 showed an initial decline between 1942 and 1974 but an increase from 1979 onwards. Back‐calculated growth rates of 50 female silver eels caught in 1998 showed that most (90%) exhibited a period of accelerated linear growth commencing at lengths between 380 and 660 mm (mean 598 mm); this accelerated growth coincided with a change in diet to piscivory. The onset of maturity was more closely associated with length than age, condition, or growth rate. The increase in average length of female silver eels of 250 mm over the past 20 years is consistent with the hypothesis that female eels adopt a size‐maximizing growth strategy to ensure maximum fecundity; this is the first time this hypothesis has been demonstrated from temporal changes within a single population.