A metatranscriptomic analysis of changing dynamics in the plankton communities adjacent to aquaculture leases in southern Tasmania, Australia.

Aquaculture releases nitrogen to the marine environment, potentially changing dynamics of local plankton populations and causing adverse impacts. Metatranscriptomics have been used to study planktonic nutrient cycles and community dynamics. We hypothesised that the metatranscriptome could be used to monitor changing phytoplankton physiology near leases. To test this hypothesis, opportunistic samples were collected from one oceanic location in winter and one estuarine location in spring and analysed via RNASeq. Transcriptomes from different locations were found to have little overlap, due to different community compositions in the oceanic and estuarine locations. Transcript function was similar at each location. Proximity to the salmon pen had little influence over the transcriptome at the estuarine location. In the oceanic environment, diatom-based activity decreased near pens and dinoflagellate-based activity increased as demonstrated through the abundance of carbon fixation and nitrogen-acquisition-related transcripts. Our initial results suggest that the use of the metatranscriptome in monitoring is promising.

Prostate Knowledge, Attitudes and Beliefs in Black College Men: A Qualitative Study.

This qualitative study explores prostate cancer knowledge and risk in Black college men. Using the Health Belief Model as a guide, focus groups and interviews were conducted with 35 Black males at a historically black college and university. Thematic analysis was conducted and general themes were found. Results indicate that Black college males have very little knowledge and understanding of what their prostate is and what it does. They are also unaware of their risk of developing prostate cancer. Additionally, while many believe prostate cancer is severe, few believe they are susceptible to getting it. These findings suggest more work needs to be done to educate young Black males on not only their prostate and prostate cancer, but on their general health. Efforts should focus on increasing the health knowledge of younger Black males in addition to that of middle-aged and older Black males so that health disparities can decrease.

Consumption of aquaculture waste affects the fatty acid metabolism of a benthic invertebrate.

Trophic subsidies can drive widespread ecological change, thus knowledge of how keystone species respond to subsidies is important. Aquaculture of large carnivorous fish generates substantial waste as faeces and lost feed, providing a food source to mobile benthic invertebrates. We used a controlled feeding study combined with a field survey to better understand the interaction between salmon aquaculture and the sea urchin, Echinus acutus, a dominant mobile invertebrate in Norwegian fjords. We tested if diets affected urchin fatty acid composition by feeding them one of three diet treatments ("aquafeed", "composite" and "natural") for 10weeks. To test if proximity to fish farms altered E. acutus fatty acid composition, populations were sampled at 10 locations in Hardangerfjord and Masfjord (Western Norway) from directly adjacent and up to 12km from farms. Fatty acids were measured in gonads and eggs in the diet experiment and in gonads and gut contents from wild animals. Urchins directly assimilated aquaculture waste at farm sites, as evidenced by elevated linoleic acid (LA), oleic acid (OA) and ∑LA, OA in their tissues. The diet experiment highlighted the biosynthetic and selective dietary sparing capacity of E. acutus in both gonads and eggs, with evidence for the elongation and desaturation of eicosapentaenoic acid (EPA) and arachidonic acid (ARA) from C18 fatty acid precursors. Elevated biosynthesis of non-methylene interrupted (NMI) fatty acids, in particular 20:3Δ7,11,14 and 20:2 Δ5,11, were also linked to a high C18 fatty acid, low ≥C20 long-chain polyunsaturated fatty acid (LC-PUFA) diet. Fatty acid composition of gonads of wild urchins indicated a highly variable diet. The study indicates that the generalist feeding ecology of E. acutus, coupled with extensive biosynthetic capacity, enables it to exploit aquaculture waste as an energy-rich trophic subsidy.

Future aquafeeds may compromise reproductive fitness in a marine invertebrate.

Aquaculture of higher trophic level species is increasingly dependent on the use of terrestrial oil products. The input of terrestrially derived n-6 polyunsaturated fatty acids (PUFA) into marine environments has subsequently increased, with unknown consequences for recipient species. We exposed a sea urchin, Heliocidaris erythrogramma to three experimental diets for 78 days: a high n-3 PUFA marine imitation treatment, a high n-6 PUFA "future aquafeed" treatment and an intermediate "current aquafeed" treatment. Female urchins fed the high n-6 PUFA diet produced larvae with lower survival rates than all other treatments. Males fed the high n-6 PUFA diet produced no viable sperm. Fatty acid composition in reproductive material revealed comprehensive biosynthetic and dietary sparing capabilities in H. erythrogramma. Despite this, the ratio of n-6 PUFA to n-3 PUFA in reproductive tissue increased significantly with diet. We suggest alterations to this ratio is the likely mechanism of negative impact on larval development.