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Directing gonadal differentiation in bluegill, Lepomis macrochirus (Rafinesque), and black crappie, Pomoxis nigromaculatus (Lesueur), by periodic estradiol‐17β immersions
Author(s) -
Arslan Tulin,
Phelps Ronald P
Publication year - 2004
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2004.01029.x
Subject(s) - feminization (sociology) , biology , lepomis macrochirus , micropterus , population , zoology , bass (fish) , fishery , fish <actinopterygii> , demography , social science , sociology
We investigated the feminization of bluegill and black crappie by short periodic immersions in an aqueous estradiol‐17β (E 2 ) solution. Bluegill fry (13.8 mm) were immersed in a 1 mg L −1 E 2 solution every 5 days on three occasions over an 11‐day period. In the positive control treatment, the same cohort of fry was fed 200 mg kg −1 E 2 diet for 45 days. Two different size (26.1 and 20.1 mm) but the same age (45 days old) black crappie fry were immersed in the same concentration of E 2 solution for 5 h a day every 3–5 days on 10 occasions between 45 and 86 days post hatch. Both modes of E 2 administration were effective to induce feminization in bluegill. Feeding fry E 2 impregnated diet for 45 days yielded 99.3% female populations from a 38.8% female experimental population. Only three short‐time E 2 immersions of fry over a much shorter treatment period also produced 76.9% female populations. E 2 immersions had no effect on sex ratios of larger black crappie fry and produced variable levels of feminization (60–82% female) in smaller black crappie fry. Results of the present study showed that feminization in both species can be achieved by periodic immersions of fry in a 1 mg L −1 E 2 solution with no adverse effects on survival. Yet, further researches on timing and intensity of immersion treatments are still needed for optimization of the procedures.