Abnormalities in the ovaries of sockeye salmon spawners in the Kamchatka River in 2019

Based on histological analysis of the ovaries of sockeye salmon spawners in the Kamchatka River, numerous abnormalities leading to resorption are shown in the structure of vitellogenic oocytes. Fertility of mature female sockeye salmon decreases due to the resorption of the vitellogenic oocytes. Presence of ovaries with abnormal oocytes implies oocyte resorption in fish being a phenomenon associated with mechanism of natural regulation of final fertility. Such mechanism is required in view of changing fish body length and weight in the sockeye salmon of the Kamchatka River. Numerous abnormalities in the ovaries indicate of a decreasing reproductive capacity of spawners and commercial quality of the eggs.

Genotyping-in-Thousands by sequencing panel development and application to inform kokanee salmon (Oncorhynchus nerka) fisheries management at multiple scales

The ability to differentiate life history variants is vital for estimating fisheries management parameters, yet traditional survey methods can be inaccurate in mixed-stock fisheries. Such is the case for kokanee, the freshwater resident form of sockeye salmon (Oncorhynchus nerka), which exhibits various reproductive ecotypes (stream-, shore-, deep-spawning) that co-occur with each other and/or anadromous O. nerka in some systems across their pan-Pacific distribution. Here, we developed a multi-purpose Genotyping-in-Thousands by sequencing (GT-seq) panel of 288 targeted single nucleotide polymorphisms (SNPs) to enable accurate kokanee stock identification by geographic basin, migratory form, and reproductive ecotype across British Columbia, Canada. The GT-seq panel exhibited high self-assignment accuracy (93.3%) and perfect assignment of individuals not included in the baseline to their geographic basin, migratory form, and reproductive ecotype of origin. The GT-seq panel was subsequently applied to Wood Lake, a valuable mixed-stock fishery, revealing high concordance (>98%) with previous assignments to ecotype using microsatellites and TaqMan® SNP genotyping assays, while improving resolution, extending a long-term time-series, and demonstrating the scalability of this approach for this system and others.

Total Mercury Concentration of Wild Caught Fish Purchased from Grocery Stores: A Potential Public Health Concern

Methylmercury is a highly toxic organic compound that bioaccumulates and biomagnifies in the human body when absorbed by the gastrointestinal tract after ingestion.1 Thus, monitoring methylmercury levels in fish is crucial for protecting public health and preventing dramatic scenarios such as the Minamata disease crisis in Japan. In this study, three different species of wild caught fish – Sockeye Salmon (Oncorhynchus nerka) from Alaska, USA; tuna imported from Vietnam; and swordfish (Xiphias gladius) imported from Indonesia – were collected from a Harris Teeter grocery store in Washington D.C. Total mercury concentration was measured by ICP-MS and the analyzed samples’ concentrations were 19.8 ± 2.9 ppb, 2.67 ± 0.01 ppm, and 380 ± 9 ppb for Sockeye Salmon, swordfish, and tuna, respectively.

Total Mercury Concentration of Wild Caught Fish Purchased from Grocery Stores: A Potential Public Health Concern

Methylmercury is a highly toxic organic compound that bioaccumulates and biomagnifies in the human body when absorbed by the gastrointestinal tract after ingestion.1 Thus, monitoring methylmercury levels in fish is crucial for protecting public health and preventing dramatic scenarios such as the Minamata disease crisis in Japan. In this study, three different species of wild caught fish – Sockeye Salmon (Oncorhynchus nerka) from Alaska, USA; tuna imported from Vietnam; and swordfish (Xiphias gladius) imported from Indonesia – were collected from a Harris Teeter grocery store in Washington D.C. Total mercury concentration was measured by ICP-MS and the analyzed samples’ concentrations were 19.8 ± 2.9 ppb, 2.67 ± 0.01 ppm, and 380 ± 9 ppb for Sockeye Salmon, swordfish, and tuna, respectively.

Enhancing cultural food security among the Syilx Okanagan adults with the reintroduction of Okanagan Sockeye salmon

For the Syilx Okanagan Nation, food sovereignty is foundational to ensuring their cultural food security and health. Salmon being a central Syilx food, the Nation has worked relentlessly since the 1990s to reintroduce Okanagan Sockeye salmon into their traditional territory. This study describes the reach of this initiative and assesses its impact on Syilx households’ income-related and cultural household food security status. In total, 265 households participated in the study. Overall, 48.6% of participants ate Okanagan Sockeye salmon during the year prior to the survey. Most participants (89.1%) reported that during the prior year their household accessed salmon from a community member or through trade (53.7%), community program (49.8%), a feast or ceremony (35.8%), or household harvest (27.2%). The number of ways that households accessed salmon was associated with a greater frequency of salmon consumption (p<0.0001). Income-related (46.5%) and cultural (63.1%) food insecurity were prevalent. Households’ access to salmon was significantly associated with cultural food security and the perceived importance of cultural food security. This study suggests Indigenous food sovereignty initiatives can increase traditional food access and consumption, thereby enhancing cultural food security. They should be supported by governments, organizations and corporations. Novelty points ●Indigenous food sovereignty initiatives can increase traditional food access and consumption, thereby enhancing cultural food security. ●Indigenous-led wild habitat restoration interventions can help reconcile past social and environmental injustices.

Microbiome population dynamics of cold smoked sockeye salmon during refrigerated storage and after culture enrichment

Cold smoked salmon is a ready-to-eat seafood product of high commercial importance. The processing and storage steps facilitate the introduction, growth and persistence of foodborne pathogens and spoilage bacteria. The growth of commensal bacteria during storage and once the product is opened also influence the quality and safety of cold smoked salmon. Here we investigated the microbial community through targeted 16s rRNA gene and shotgun metagenomic sequencing, as means to better understand the interactions among bacteria in cold smoked salmon. Cold smoked salmon samples were tested over 30 days of aerobic storage at 4℃ and cultured at each timepoint in buffered Listeria enrichment broth (BLEB) commonly used to detect Listeria in foods. The microbiomes were comprised of Firmicutes and Proteobacteria namely, Carnobacterium , Brochothrix , Pseudomonas , Serratia , and Psychrobacter . Pseudomonas species were the most diverse species with 181 taxa identified. Additionally, we identified potential homologs to 10 classes of bacteriocins in microbiomes of cold smoked salmon stored at 4°C and corresponding BLEB culture enrichments. The findings presented here contribute to our understanding of microbiome population dynamics in cold smoked salmon, including changes in bacterial taxa during aerobic cold storage and after culture enrichment. This may facilitate improvements to pathogen detection and quality preservation of this food.

Stock-recruitment models, principles of management and rules for regulating the fishery on the main Chukotka stocks of sockeye and chum salmon

Fishery pressure on populations of pacific salmons has increased in the Rusian Far East in the last decade because of growing fishing and processing capacity, so measures for the fishery regulation are necessary, as the regime of pass days in rivers and marine coastal areas. Chukotka is now almost the only region where such restrictions are still absent. However, if the interest of fishery industry to the stocks of pacific salmon in Chukotka will grow, a successful scientifically based strategy of fishery should be developed to maintain exploitation of the stocks without exceeding the limits of excessive use. Year-to-year time series on spawning stock and recruitment of chum salmon in the Anadyr area and sockeye salmon in the Meynypilgyn area were analysed for development of recruitment models and establishment of general principles for adaptive fishery management. Nonlinear adaptive fishery management based on principles of buffer managing is proposed and tested under various regimes of landing using the stock simulation models accounting deviations from the standard stock-recruitment model. There is concluded that the level of exploitation is much lower than optimal for the Anadyr chum salmon, whereas escapement for spawning of the Meynypilgyn sockeye salmon should be increased in cases of low spawning stock of this species.

Analysis of Sr and Ba profiles measured by ultra-high-resolution mass spectrometry LA-ICP-MS in otoliths of juvenile anadromous sockeye salmon Oncorhynchus nerka in the early marine life-history stage as a proxy for fresh to marine water transition

The strontium (Sr) and barium (Ba) profiles in otoliths of juvenile sockeye salmon Oncorhynchus nerka from British Columbia are measured using a Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) system and analyzed. The highest possible measurement resolution (near-daily) was used to assess variability and repeatability of the breakpoint (marine entry) estimates inferred from Sr:Ca and Ba:Ca ratios. Such resolution for the otolith chemical composition (to an accuracy of 2 μm) was reached using the rotating slit, which width was close to the daily circulus width of the otoliths. So, daily or 2-day changes in the elemental composition were recorded during the period of transition to the marine environment. Sr profiles were generally similar among the fish, starting with low values of Sr:Ca in the fresh water and increasing sharply after the marine entry. The Ba:Ca signal was more complex, showing in most cases a dramatic increase immediately before the breakpoint. Besides, multiple peaks in the Ba profiles were recorded prior to the marine transition with a significant difference of their number between fish from different populations. A breakpoint was detectable in the Ba profiles 3–11 µm prior to its appearance in the Sr profiles. The complexity of Ba profiles may cause erroneous estimates of the marine entry date; thus, the Sr signal is a more reliable marker of marine transition for juvenile sockeye.