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Sexual Development of the Croaker, Micropogon Undulatus, and Distribution of the Early Stages in Chesapeake Bay
Author(s) -
Wallace David H.
Publication year - 1941
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1940)70[475:sdotcm]2.0.co;2
Subject(s) - biology , bay , sexual maturity , fishery , development of the gonads , chesapeake bay , gonad , fish <actinopterygii> , zoology , sex ratio , ecology , estuary , demography , oceanography , population , anatomy , geology , sociology
Croakers of varying ages and with approximately an equal distribution of the sexes were studied to determine gonad development. Data gathered indicate that males mature earlier than females. The smallest male to reach sexual maturity was 24 centimeters long, whereas smallest ripe female was 27.5 centimeters long, total length. The ages of these fish, as indicated by scale examinations, were 2 and 3 years, respectively. All fish 3 years or older had ripening gonads. The fish studied were collected by random sampling, in which the ratio of males to females in the areas changed from 50:50 in June to a ratio of approximately 35:65 during early August. This evidence, further supported by records of ocean catches, indicates that males begin their spawning migrations out of the bay earlier than females. At the time of departure whether males or females, the gonads have reached comparatively complete maturity. Evidence based upon tagging, gonad development, and samples from commercial catches, shows that sexually mature croakers leave bay waters largely during the month of August, and that virtually all fish have departed by September 15, the greatest wave of migration taking place during the first week in August. Sexually mature croakers return to the Chesapeake Bay waters during late spring. During the winters of 1938, 1939 and 1940, larval stages of the croaker were taken within the Bay. It was possible, through the use of a specially constructed otter trawl, to gather materials which provided information on growth and up‐bay distribution of very young stages. The presence of larval croakers well up in the bay can be explained by currents which carried the young fish up the bay from the oceanic spawning areas.