Tilapia (Oreochromis spp.) were collected seasonally from four contaminated rivers in southwestern Taiwan for studies of morphological deformities that could be used as biomarkers of contamination. Morphological deformities found in tilapia were separated into 15 categories. Overall, the prevalence of deformities such as split fins, lower lip extension and gill deformities were significantly related to various water quality parameters, including low DO and high ammonium, lead and zinc concentrations. The persistence of tilapia in polluted waters and the development of a suite of morphological deformities suggest that tilapia can be used as sentinels of non-point source pollution in rivers.

We report the construction of a genome-wide fish metabolic network model, MetaFishNet, and its application to analyzing high throughput gene expression data. This model is a stepping stone to broader applications of fish systems biology, for example by guiding study design through comparison with human metabolism and the integration of multiple data types. MetaFishNet resources, including a pathway enrichment analysis tool, are accessible at http://metafishnet.appspot.com.

Objective: This paper highlights the complexity of marine fish spawner–recruit systems and how they vary across species and ecosystems while providing a universal terminology and framework to evaluate fish reproduction. We emphasize the gonadal development important to assess maturity, fecundity, where and when fish spawn, and transition and sex assignment in protogynous species.Methods: We review and compare reproductive traits in warmwater and coldwater fishes. Reproductive phases for both sexes and protogynous species are defined and histological micrographs presented. New methods are developed to assess maturity; spawning seasonality; peak spawning; and, for protogynous species, sex assignment.Result: Protogyny, extended spawning seasons, and indeterminate fecundity are more common in warmwater than coldwater systems. The following reproductive phases are defined as immature, transitional (sex change), early developing (the first stage of entrainment in the reproductive cycle), late developing (stages needed to complete maturational competence), spawning, regressing (spawning season termination), and regenerating (fish that are mature but outside of the spawning season). A method to assess the certainty of maturity assignment based on reproductive phase and the age and size range sampled is presented, as are best practices to estimate size and age at maturity. To remove the subjectivity from current methods to estimate spawning seasonality, we present a new quantitative method to identify the core spawning season and peak spawning months.Conclusion: A species’ ability to adapt to fishing and climate change varies with their reproductive strategy. Improving our understanding of fish reproduction necessitates standardizing methodology and terminology.