Methodology for estradiol treatment in marine larval and juvenile fish: uptake and clearance in summer flounder

J.L. Specker, M.K. Chandlee-2002
Aquaculture, 217(1-4): 663-642
Abstract:

Female flatfish grow faster than males. Our goal is to use immersion in estradiol as a method for producing all female populations of summer flounder (Paralichthys dentatus). To this end, we measured uptake and clearance of estradiol in the whole-body of larval and juvenile summer flounder. Uptake reached an initial plateau within 30 min and was accumulated above the exposure concentration (EC) in juveniles, but not larvae. An EC of 16 nM significantly elevated whole-body estradiol concentrations in both larvae and juveniles. We recommend an EC of 50–100 nM to raise estradiol levels to high physiological levels. Depuration was significant within 4 h after transfer to clean water and complete after 24 h. Estradiol in the exposure water was lowered to undetectable levels within 1 h of charcoal filtration. This information should be useful to investigators working on sex differentiation in this and other species, or in the areas of vitellogenin biology and endocrine disruption.

(Graduate School of Oceanography, University of Rhode Island, 218 South Ferry Rd., Narragansett, RI 02882-1197, USA, e-mail: jspecker@gso.uri.edu)

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