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Seasonal variation of egg size in the sardine, Sardino pilchardus Walb., of the Saronikos Gulf: causes and a probable explanation
Author(s) -
Daoulas Ch.,
Economou A. N.
Publication year - 1986
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.1095-8649.1986.tb05182.x
Subject(s) - sardine , biology , intraspecific competition , growth rate , plankton , biomass (ecology) , ecology , zoology , fishery , fish <actinopterygii> , geometry , mathematics
The change of egg size in sardine of the Saronikos Gulf (Greece) during the course of the spawning season is examined in relation to the changing conditions of temperature and plankton biomass. It is suggested that the intraspecific variation of egg size is an ecophenotypic rather than a genetic phenomenon, arising from the disturbance of the normal ratio between growth and differentiation rates during the oocyte stage. Assuming that a positive relation between the growth rate of the mother and the growth rate of the eggs during maturation exists, environmental or endogenous factors promoting or retarding the adult growth rate will accelerate or decrease the growth rate of the eggs in relation to the rate of differentiation, resulting in smaller or bigger eggs respectively.