The Effects of Capture and Time Out of Water on Sablefish (Anoplopoma fimbria) Reflexes, Mortality, and Health

It is unknown if capture coupled with time out of water on-deck affect sablefish (Anoplopoma fimbria) health and reflexes, and whether it contributes to acute or delayed mortality. In this study, 35 sablefish were caught using hook-and-line gear and given six reflex tests after capture. Thirty-two were subsequently transported to the laboratory, held for 45–52 days, and then experimentally held out of the water for either 0, 3, 6, or 11 min. After 7–10 days of holding in the laboratory after the experiment, to monitor for mortalities, reflexes were tested for a second time and necropsies and histopathology were performed. There were no histological findings and no mortalities; however, parasites and minor inflammation were observed. All occurrences were not a result of capture or experiments. Some reflexes were absent after capture (77% could right themselves, 69% responded to a tail grab, and 57% responded to sound.) The only test where the reflex did not improve to 100% in the laboratory was the sound reflex. The sound reflex was highest for control fish (63%) and there were no positive sound reflexes for fish held out of water for 11 min. The absence of reflexes may result in predation after release and present issues with feeding or communication.

Research on sablefish ( Anoplopoma fimbria ) suggests that limited capacity to increase heart function leaves hypoxic fish susceptible to heat waves

Studies of heart function and metabolism have been used to predict the impact of global warming on fish survival and distribution, and their susceptibility to acute and chronic temperature increases. Yet, despite the fact that hypoxia and high temperatures often co-occur, only one study has examined the effects of hypoxia on fish thermal tolerance, and the consequences of hypoxia for fish cardiac responses to acute warming have not been investigated. We report that sablefish ( Anoplopoma fimbria ) did not increase heart rate or cardiac output when warmed while hypoxic, and that this response was associated with reductions in maximum O 2 consumption and thermal tolerance (CT max ) of 66% and approximately 3°C, respectively. Further, acclimation to hypoxia for four to six months did not substantially alter the sablefish's temperature-dependent physiological responses or improve its CT max . These results provide novel, and compelling, evidence that hypoxia can impair the cardiac and metabolic response to increased temperatures in fish, and suggest that some coastal species may be more vulnerable to climate change-related heat waves than previously thought. Further, they support research showing that cross-tolerance and physiological plasticity in fish following hypoxia acclimation are limited.

Increasing value through gear flexibility: A case study of U.S. West Coast Sablefish

This paper explores the potential economic gains of allowing additional flexibility in gear-choice, within rights-based management programs. A case study of U.S. West Coast sablefish (Anoplopoma fimbria) provides an example of a commercially important species where gear-switching is currently occurring within the IFQ program, allowing us to isolate the economic potential of gear flexibility along two important margins: size and quality. We conduct a hedonic price analysis of ex-vessel prices using panel fish ticket data and linear mixed-effect econometric models to examine the influences of gear, size, condition, fishing sector, port group, landing month and year on the price of sablefish. We generate a counter-factual scenario that represents the IFQ fishery where the use of fixed-gear is prohibited, by predicting what the size-composition of catch would have been if the sablefish had been caught with trawl gear. We find that the flexibility of targeting sablefish with fixed gear between 2011-2016 generated an annual average 10.45% increase in total revenue, or $1.17M, compared to the trawl-only scenario. These results show sablefish value increases through implementing gear flexibility, which contributes to a broader conversation of allocative efficiency.

Sablefish (Anoplopoma fimbria) plasma biochemistry and hematology reference intervals including blood cell morphology

Plasma biochemistry and hematology reference intervals are integral health assessment tools in all medical fields, including aquatic animal health. As sablefish (Anoplopoma fimbria) are becoming aquaculturally and economically more important, this manuscript provides essential reference intervals (RI) for their plasma biochemistry and hematology along with reference photomicrographs of blood cells in healthy, fasted sablefish. Blood cell counts and morphology can vary between species, precluding the use of RI’s from other fish species for use in sablefish. Blood was collected for plasma biochemistry and hematology analysis between June 20 and July 18, 2019, from healthy, yearling sablefish, hatched and reared in captivity on a commercial diet. Overnight fast of 16-18 hours did not sufficiently reduce lipids in the blood, which lead to visible lipemia and frequent rupture of blood cells during analysis. Therefore, sablefish should be fasted for 24 to 36 hours before blood is collected to reduce hematology artifacts or possible reagent interference in plasma biochemistry analysis. RI’s may also be influenced by feed, demographics, and production systems, warranting more studies on this topic. In sablefish, lymphocytes are the dominant leukocytes (98%), while eosinophils are rare, and basophils were not detected. Neutrophils are very large cells with Döhle bodies. These bodies are usually signs of toxic changes, but no such association was found in these fish.

Adaptive Behaviors to Marine Ecosystem Shifts: Examining Fishermen’s Strategies in Response to Abundant Juvenile Sablefish (Anoplopoma fimbria) in Alaska

Over recent years there have been rapid changes occurring across marine ecosystems worldwide, with high latitude systems seeing ecosystem shifts emerging at unprecedented rates. The Gulf of Alaska and Bering Sea marine ecosystems have experienced substantial fluctuation in fish stocks, with some species experiencing considerable decreases while others thrive. Following the marine heatwave of 2014, sablefish (Anoplopoma fimbria) had a historically unparalleled juvenile recruitment class that is now dominating the stock composition. While this recruitment class bodes well for future fisheries, it is currently undermining the value of the fishery with limited incentives to retain the smaller and less valuable fish, compounding adverse effects on earnings in the fishery due to whale depredation that has been occurring for years. This study examines the well-being implications of fishermen’s adaptive strategies to these ecosystem conditions within the Alaska sablefish fishery using a socio-ecological system framework, operationalized as a qualitative network model (QNMs) and quantitative indicators. We examine the extent to which adaptation strategies, derived from a literature review and stakeholder interviews, are being utilized in the fishery with quantitative indicators. These strategies are then examined with QNMs that explore their impacts across the spectrum of well-being. By coupling quantitative indicators and QNMs, we were able to demonstrate how adaptive strategies can be examined to capture the multi-faceted well-being effects of fisheries participants’ adaptations to changing conditions. This study directly addresses several of the key guiding principles of the U.S. EBFM Road Map, including advancing our understanding of ecosystem processes, exploring trade-offs within an ecosystem, and maintaining resilient ecosystems, inclusive of community well-being. Thus this paper demonstrates how coupled socio-ecological models can elevate the inclusion of human adaptive behaviors, providing a framework for the development of policymaking that can mitigate adverse effects on both the participants and the resource by facilitating the mixture of adaptive strategies that maximizes desired well-being outcomes.