Ecology and behaviour during early life stages of fishes: theory and application

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Most species of fish produce many eggs (r-selected). For example, a female winter flounder (Pseudopleuronectes americanus) can produce up to 3 million eggs per year and is reproductive for an average of 7 years. However, very few embryos survive to reproduction. Mortality rates for these r-selected species, both in field and aquaculture settings, are extremely high during the first year of life. This life-history strategy is of fundamental importance to our understanding of fish population dynamics and a significant challenge to aquaculture development. Together with my students, I study ecology and behaviour of fishes during these important early life stages. I propose to continue my research in five areas: 1) effects of yolk and lipid quantity and quality on larval size and performance, 2) importance of maternal and paternal contributions to offspring variability in size and performance, 3) heritability of these traits, 4) effects of abiotic factors on growth and survival and their interactions with areas 1 through 3, and 5) development of spatial ecological models of egg, larval and juvenile distributions. Over the past few years my lab has developed a number of advanced tools to investigate the effects of genotype on performance traits (phenotype) of fishes. We developed the first successful microinjection system to control size and constituents of yolk reserves in fish embryos. We also recently developed efficient sperm cryopreservation protocols for winter flounder, cod and haddock. These two advances provide us with the opportunity to examine the relative contributions of the parents to offspring performance. While these biotic factors are extremely important, we also have to understand how abiotic (physical) factors may affect them. We will continue to conduct laboratory-based experiments to provide information on how abiotic factors (such as temperature), relevant to ecology and aquaculture, affect fish growth and survival. This data will be used with field analyses to study where fish go and why. This aspect of spatial ecology provides a key link between small-scale laboratory experiments and the study of wild populations.