Mass mortality events (MMEs) are defined as the death of large numbers of fish over a short period of time. These events can result in catastrophic losses to the Atlantic salmon aquaculture industry and the local economy. However, they are challenging to understand because of their relative infrequency and the high number of potential factors involved. As a result, the causes and consequences of MMEs in Atlantic salmon aquacul...

Introduction Seagrass meadows serve as an integral component of coastal ecosystems but are declining rapidly due to numerous anthropogenic stressors including climate change. Eelgrass wasting disease, caused by opportunistic Labyrinthula spp., is an increasing concern with rising seawater temperature. To better understand the host-pathogen interaction, we paired whole organism physiological assays with dual transcriptomic anal...

Disease and parasitism cause major welfare, environmental and economic concerns for global aquaculture. In this review, we examine the status and potential of technologies that exploit genetic variation in host resistance to tackle this problem. We argue that there is an urgent need to improve understanding of the genetic mechanisms involved, leading to the development of tools that can be applied to boost host resistance and...

This study was conducted to determine the effects of a co‐infection with Moritella viscosa at different exposure levels of sea lice Lepeophtheirus salmonis in Atlantic salmon ( Salmo salar ). M. viscosa (1.14 × 10 6 cfu/ml) was introduced to all experimental tanks at 10 days post‐lice infection (dpLs). Mean lice counts decreased over time in both the medium lice co‐infection (31.5 ± 19.0 at 7 dpLs; 16.9 ± 9.3 at 46 dpLs) and h...

Genomic approaches permit direct estimation of inbreeding and its effect on fitness. We used genomic‐based estimates of inbreeding to investigate their relationship with eight adult traits in a captive‐reared Pacific salmonid that is released into the wild. Estimates were also used to determine whether alternative broodstock management approaches reduced risks of inbreeding. Specifically, 1,100 unlinked restriction‐site associ...

Syngnathidae (seahorses, seadragons and pipefish) suffer significant losses from non‐tuberculous mycobacteria. However, they produce markedly different lesions in response to the disease compared to other teleost species, notably infrequent granuloma formation. This study evaluated 270 syngnathid fish, from which 92 were diagnosed with mycobacteriosis by histopathology, culture or both. Microscopic lesions variably consisted o...

The immune status of young‐of‐the‐year ( YOY ) winter flounder Pseudopleuronectes americanus was evaluated in fish collected from six areas around Long Island, NY, U.S.A. representing more urban areas with high population density in the west, to less densely populated more rural areas in to the east. Gene expression markers for innate immunity ( pleurocidin ) and contaminant exposure (cytochrome P4501A ; cyp1a ) were measured...

Several immunostimulatory feed additives have shown the ability to induce protective responses in A tlantic salmon to infection with L epeophtheirus salmonis . However, even the most encouraging results rarely surpass a 50% protective index in the host. That fact coupled with the well‐documented limitations of single‐therapy strategies in the effective management of parasitic infections generally make it imperative to identify...

Control of sea lice, L epeophtheirus salmonis , on farmed A tlantic salmon, S almo salar , relies heavily on chemotherapeutants. However, reduced efficacy of many treatments and need for integrated sea lice management plans require innovative strategies. Resistance to emamectin benzoate (EMB), a major sea lice parasiticide, has been linked with P‐glycoprotein (P‐gp) expression. We hypothesized that host immunostimulation would...

Lepeophtheirus salmonis infections in Atlantic salmon, S almo salar , have been characterized by little to no hyperplastic response and a biphasic immune response that results in chronic inflammation with tissue repair as the infection progresses. We hypothesized that C p G administration with prior lice exposure would enhance epithelial inflammatory mechanisms and boost the A tlantic salmon immune response to L . salmonis , l...

The copepod parasite, Dichelesthium oblongum , is known to infect the Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus , within the area near New York city, USA, known as the NY Bight. The gross pathology associated with the juvenile and adult copepod stages along with the parasite’s link in causing changes in sturgeon osmoregulatory capabilities has led us to investigate the host immunophysiology in relation to this host–pa...

Integrating knowledge from across the natural and social sciences is necessary to effectively address societal tradeoffs between human use of biological diversity and its preservation. Collaborative processes can change the ways decision makers think about scientific evidence, enhance levels of mutual trust and credibility, and advance the conservation policy discourse. Canada has responsibility for a large fraction of some ma...

Brown trout populations in the Hardanger Fjord, Norway, have declined drastically due to increased exposure to salmon lice from salmonid aquaculture. We studied contemporary samples from seven populations and historical samples (1972 and 1983) from the two largest populations, one of which has declined drastically whereas the other remains stable. We analysed 11 microsatellite loci, including one tightly linked to the UBA gene...