Gamete quality in fish: evaluation parameters and determining factors.

The quality of fish gametes, both male and female, are determined by several factors (age, management, feeding, chemical and physical factors, water quality, etc.) that have an impact on the survivability of embryos, larvae and/or fry in the short or long term. One of the most important factors is gamete ageing, especially for those species that are unable to spawn naturally in hatcheries. The chemical and physical factors in hatcheries and the nutrition that they provide can significantly alter harvest quality, especially from females; as a rule, males are more tolerant of stress conditions produced by inadequate feeding, management and/or poor water conditions. The stress produced on broodstock by inadequate conditions in hatcheries can produce adverse effects on gamete quality, survival rates, and the embryonic eggs after hatching.