Dietary Exposure to Environmentally Relevant Levels of Chemical Contaminants Reduces Growth and Survival in Juvenile Chinook Salmon.

Chemical pollution can degrade aquatic ecosystems. Chinook salmon in contaminated habitats are vulnerable to health impacts from toxic exposures. Few studies have been conducted on adverse health outcomes associated with current levels and mixtures of contaminants. Fewer still address effects specific to the juvenile life-stage of salmonids. The present study evaluated contaminant-related effects from dietary exposure to environmentally relevant concentrations and mixture profiles in juvenile Chinook salmon from industrialized waterways in the U.S. Pacific Northwest using two end points: growth assessment and disease susceptibility. The dose and chemical proportions were reconstituted based on environmental sampling and analysis using the stomach contents of juvenile Chinook salmon recently collected from contaminated, industrialized waterways. Groups of fish were fed a mixture with fixed proportions of 10 polychlorinated biphenyls (PCBs), 3 dichlorodiphenyltrichloroethanes (DDTs), and 13 polycyclic aromatic hydrocarbons (PAHs) at five concentrations for 35 days. These contaminant compounds were selected because of elevated concentrations and the widespread presence in sediments throughout industrialized waterways. Fork length and otolith microstructural growth indicators were significantly reduced in fish fed environmentally relevant concentrations of these contaminants. In addition, contaminant-exposed Chinook salmon were more susceptible to disease during controlled challenges with the pathogen Aeromonas salmonicida. Our results indicate that dietary exposure to contaminants impairs growth and immune function in juvenile Chinook salmon, thereby highlighting that current environmental exposure to chemicals of potential management concern threatens the viability of exposed salmon.

A labeled data set of underwater images of fish and crab species from five mesohabitats in Puget Sound WA USA.

The sustainable management of fisheries and aquaculture requires an understanding of how these activities interact with natural fish populations. GoPro cameras were used to collect an underwater video data set on and around shellfish aquaculture farms in an estuary in the NE Pacific from June to August 2017 and June to August 2018 to better understand habitat use by the local fish and crab communities. Images extracted from these videos were labeled to produce a data set that is suitable for use in training computer vision models. The labeled data set contains 77,739 images sampled from the collected video; 67,990 objects (fishes and crustaceans) have been annotated in 30,384 images (the remainder have been annotated as "empty"). The metadata of the data set also indicates whether a physical magenta filter was used during video collection to counteract reduced visibility. These data have the potential to help researchers address system-level and in-depth regional shellfish aquaculture questions related to ecosystem services and shellfish aquaculture interactions.