Aquaculture-derived terrestrial fatty acids in marine food webs

© 2017 Dr. Camille Anna WhiteAquaculture is an increasingly common trophic subsidy in coastal marine ecosystems, with waste feed, faecal material and nitrogenous wastes potential food sources for marine consumers. As modern aquafeeds are generally high in terrestrial lipids and oils, the biochemical composition of the aquaculture-derived subsidy is relatively alien in the marine environment. Using terrestrial fatty acids as a tool, I investigated dispersal and uptake of the aquaculture subsidy, in both laboratory and field scenarios. I was able to demonstrate that aquaculture outputs are widely dispersed in marine systems and assimilated by marine species. Using marine amphipods and sea urchins as model species, I examined maternal and multigenerational effects of increased terrestrial lipids in the diet of marine consumers. I found that consuming waste could alter both biochemical composition and reproductive outputs in invertebrate fauna. When applied to a field scenario, where aquaculture outputs have been linked to increases in sea urchins, I found that population-scale effects will be a trade-off between energetic benefits of consuming a lipid-rich subsidy, versus any negative effects that a high terrestrial diet may have on reproductive outcomes