Because cunner eggs are buoyant for a period of hours after spawning, each tank was fitted with a top drain to siphon surface water and spawned eggs.
In the laboratory, cunner routinely spawned in the afternoon, and eggs were rinsed from collection cups the next morning for counting.
Cunner were exposed to 17[beta]-estradiol, ethynylestradiol, or estrone using a subcutaneous slow-release implant system developed in our laboratory (25).
To obtain a purified sample of cunner vitellogenin, three males were injected twice, 5 days apart, with 17[beta]-estradiol in coconut oil.
Vitellogenin in plasma samples from cunner in exposure experiments with either 17[beta]-estradiol, estrone, or ethynylestradiol was quantified by direct enzyme-linked immunosorbent assay conducted in the Biotechnology Program Laboratory at the University of Florida.
Male cunner collected from Narragansett Bay usually have no measurable plasma vitellogenin, although we have occasionally captured males with concentrations between 0.
This may be caused by enterohepatic recirculation of this particular estrogen in cunner, similar to that recently documented in trout (29).
Although we did not measure spawning behavior in exposed cunner, our data on fertility of spawned eggs indicate no significant correlation between ability of male cunner to fertilize eggs (expressed as percent fertile eggs) and male plasma vitellogenin levels.
07) with vitellogenin concentration, which suggests that male vitellogenin concentrations in reproductively active cunner have to exceed a threshold of approximately 50 mg/mL plasma before they are indicative of reduced male GSI.
This suggests that male vitellogenin concentrations in reproductively active cunner need to exceed some threshold level (15 mg/mL plasma in our experiments) before they are indicative of deleterious reproductive effects in females.
The data presented in this article indicate that induction of vitellogenin in adult male fish cannot be used as a dependable biomarker for reproductive dysfunction in all situations; we specifically present one such case: adult male cunner exposed to estrogens through implantation for a relatively short period.
Field observations on the reproductive behaviour of the cunner, Tautogolabrus adspersus (Walbaum), in Newfoundland.
Dualistic spawning behaviour of the cunner, Tautogolabrus adspersus (Pisces: Labridae), in Bonne Bay, Newfoundland.
Population decline of tautog and cunner in Narragansett Bay, evidence from a forty-year survey.
Tissue distribution of FITC in cunner (Tautogolabrus adspersus) after subcutaneous implantation in a controlled release matrix.