Ash Heaphy: Fatty Snapper say it's all mussel

Aquaculture can influence the nutrition and ecology of wild fish through the addition of physical structure and food provisioning. Previous studies have found higher abundance and changes in the diet of some fishes associated with shellfish farms, however, the nature of any benefits to these fish in terms of improvements in nutrition or productivity are unclear. Biochemical analyses and fatty acid biomarkers were used to identify differences in the characteristics of muscle tissue, of 60 snapper (Chrysophrys auratus) caught from within and outside coastal Greenshell™ mussel farms, in the Hauraki Gulf, New Zealand. The AFDW (95%), protein (84.1%), and carbohydrate (0.3%) content of the dry mass of muscle tissue were similar for snapper inside and outside mussel farms. However, total lipid was on average 62.1% higher for mussel farms (8.5 ± 0.9%) versus controls (5.8 ± 0.3%). Additionally, mussel farm snapper contained higher levels of essential polyunsaturated fatty acids, such as DHA, indicating greater dietary contribution from flagellates, most likely from snapper consuming filter feeders, such as mussels. The findings show that mussel farms provide substantial nutritional benefits to the snapper inhabiting the farms, with significant potential for improvement in their growth and reproduction.