Sea urchin population harvest in the North Atlantic coast of Portugal was characterized in terms of gonad yield, nutritional composition and important market-related traits, over one reproductive cycle (March 2016 to March 2017). Most of the quality attributes showed a seasonal variation strongly dependent on sea urchin sex. Maximum gonad yield (18%) was observed in March 2017. A single spawning event occurred between May and July. Gonads are rich sources of protein (12–18% WW) with low fat content (≤6% WW), that increase during the gametogenic stages of recovery and growing (November-December). Polyunsaturated fatty acids were the dominant class in both sexes (4.2–14.7 mg.g −1 WW), being preferentially accumulated in females. Total gonads carotenoid varied seasonally, with the highest level being observed in males during spawning season. Echinenone was the main pigment present in gonads, showing highest concentrations in males during spawning and gonad recovering. During the growing and early maturation period gonads were more reddish, yellowish and brighter, as well as more firm, irrespectively of the sex. Based on all seasonal changes affecting gonad yield and quality, the period between November and February seems the most suitable to harvest high quality gonads in the Atlantic coast of Portugal.

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a b s t r a c tIn natural environments fish populations are exposed to many potential xenoestrogens, whereby understanding the impacts of mixtures continue to be of great interest. The main objective of this study was, therefore, to understand whether and how an environmentally relevant mixture of xenoestrogens found in the Douro River estuary can disrupt the normal gametogenesis in fish. For this purpose, adult zebrafish of both sexes were exposed for 21 days to an environmental mixture (MIX) of 11 xenoestrogens from diverse sources. A 100 ng/L ethinylestradiol (EE2) positive control was added. A quantitative (stereological) analysis with systematic sampling was made in the gonads, and using light microscopy both the relative and the absolute volumes of the gametogenic stages were estimated. Data point that the EE2 stimulus induced changes in structural compartments; with decreasing trends for the advanced maturation stages both in males and females. There was also a trend for a greater amount of interstitial tissue in males. Along with an interstitial fibrosis increase detected, the presence of a proteinaceous fluid was observed in both sexes and experimental groups (EE2 and MIX). Other histopathologic alterations were observed in the EE2 female group, such as the presence of foci of granulomatous inflammation and follicular mineralization in the germinal parenchyma and luminal areas. The most interesting finding of this study was that the exposure to the MIX caused a decrease of the relative volume of spermatozoa in zebrafish. This kind of estrogenic effect has not earlier been structurally quantified in such a fine detail with unbiased stereology in fish gonads. Despite the ultimate consequences of such disruptions being unknown, it could be logically argued that reduction or slowing-down of the appearance of the most mature cohorts and/or eventual interstitial fibrosis and other pathologic changes can adversely affect breeding. The findings add further explanatory bases for understanding the negative impacts of xenoestrogens.

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