scholarly journals Regional ocean models indicate changing limits to biological invasions in the Bering Sea

2020 ◽  
Vol 77 (3) ◽  
pp. 964-974
Author(s):  
A Droghini ◽  
A S Fischbach ◽  
J T Watson ◽  
J P Reimer
Keyword(s):  
Bering Sea ◽  
Cold Water ◽  
Water Discharge ◽  
Adult Survival ◽  
Indigenous Species ◽  
The Us ◽  
Survival And Reproduction ◽  
Suitable Area ◽  
Non Indigenous Species ◽  
The Bering Sea

Abstract Minimal vessel traffic and cold water temperatures are believed to limit non-indigenous species (NIS) in high-latitude ecosystems. We evaluated whether suitable conditions exist in the Bering Sea for the survival and reproduction of NIS. We compiled temperature and salinity thresholds of NIS and compared these to ocean conditions projected during two study periods: recent (2003–2012) and mid-century (2030–2039). We also explored patterns of vessel traffic and connectivity for US Bering Sea ports. We found that the southeastern Bering Sea had suitable conditions for the year-round survival of 80% of NIS assessed (n = 42). This highly suitable area is home to the port of Dutch Harbor, which received the most vessel arrivals and ballast water discharge in the US Bering Sea. Conditions north of 58°N that include sub-zero winter water temperatures were unsuitable for most NIS. While mid-century models predicted a northward expansion of suitable conditions, conditions for reproduction remained marginal. Only 40% of NIS assessed (n = 25) had 6 or more weeks where conditions were suitable for reproduction. Our findings illustrate the potential vulnerability of a commercially important subarctic ecosystem and highlight the need to consider life stages beyond adult survival when evaluating limits to NIS establishment.

scholarly journals Impact of changing oceanographic conditions on species composition and abundance of zooplankton on the fishing grounds at Cape Navarin and their importance for the Russian pollock fishery in the Bering Sea

2017 ◽  
Vol 189 (2) ◽  
pp. 103-120
Author(s):  
Yury I. Zuenko ◽  
Eugene O. Basyuk
Keyword(s):  
Species Composition ◽  
Bering Sea ◽  
Cold Water ◽  
Zooplankton Abundance ◽  
Zooplankton Species ◽  
Shape Dependence ◽  
Spawning Areas ◽  
Species Specific ◽  
Bering Sea Shelf ◽  
The Bering Sea

Seasonal and interannual variability of zooplankton in the area at Cape Navarin are considered on the base of long-term surveys. This area is the main fishing grounds for Russian pollock fishery in the Bering Sea. Species composition of zooplankton changes cardinally during the feeding period: large-size copepods prevail in summer, but euphausiids, mainly the krill Thysanoessa inermis - in autumn. Year-to-year changes of the zooplankton abundance are species-specific and driven by different environmental factors. The water circulation is crucially important for such allochtonous species as krill by transporting them from the spawning areas. Advection either from the south, i.e. from the continental slope (till 2006), or from the east and west, i.e. from the shelf (in 2007-2014), was observed in the last two decades that corresponded to replacing of relatively warm oceanographic regime by relatively cold regime and could be traced by dynamics of the ice cover and the cold water pool area on the eastern Bering Sea shelf. The advection from the slope provides the krill transport to the area at Cape Navarin, but conditions of the cold regime limit the transport. From the other hand, the cold oceanographic regime is favorable for reproduction of many zooplankton species, including krill, because of higher primary productivity. As the result, the krill and some other mass zooplankton species have a bell-shape dependence of their abundance on water temperature: they have the maximal biomass in relatively warm years within the cold periods and in relatively cold years within the warm periods. In the years with severe winters, the pollock starts its back migration early, in August-September because of seasonal depletion of copepods and lack of krill, while the years with warm winters are also unfavorable for long feeding of pollock in the Navarin area because of low abundance of many zooplankton species. «Moderate» conditions are optimal for long feeding of pollock in this area, when the Russian fishery continues here longer, till November-December, with the annual landings > 500,000 t (as in 1996-1999, 2001, 2007-2008).

Fatty acid composition of blubber from the four species of Bering Sea phocid seals

1979 ◽  
Vol 57 (1) ◽  
pp. 189-195 ◽  
Author(s):  
George C. West ◽  
John J. Burns ◽  
Marilyn Modafferi
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Bering Sea ◽  
Cold Water ◽  
Ringed Seal ◽  
Interspecific Differences ◽  
Phocid Seals ◽  
Chain Lengths ◽  
The Bering Sea

The fatty acid composition of blubber lipid was analyzed from one example of both sexes of the four species of phocid seals inhabiting the Bering Sea: spotted seal (Phoca vitulina largha), ringed seal (P. hispida), ribbon seal (P. fasciata), and bearded seal (Erignathus barbatus). All specimens had similar fatty acid complements (10 fatty acids predominated, ranging from chain lengths of 14 to 22 carbons with zero lo six double bonds) although there were specific differences among species and between sexes. The greatest interspecific differences in blubber fatty acid composition occurred in the ringed seal and may have been due to diet.Double-bond indices (indicating degree of unsaturation) were high in all samples and higher than those calculated for Atlantic or southern hemisphere seals. Melting points of the blubber lipid ranged from −2 to −8 °C for some components; all components melted below 15 °C correlating with expected peripheral blubber temperatures of seals in cold water of the Bering Sea.

Anticipatory Culture in the Bering Sea: Weather, Climate and Temporal Dissonance

2021 ◽  
Author(s):  
Zeke Baker
Keyword(s):  
Bering Sea ◽  
Social Life ◽  
Climate Services ◽  
Ice Dynamics ◽  
Social Patterns ◽  
Weather Patterns ◽  
Sea Ice Dynamics ◽  
Weather Forecasters ◽  
The Us ◽  
The Bering Sea

AbstractA major implication of climate change is the declining capacity for communities to anticipate future conditions and scenarios. In the Bering Sea region of Western Alaska, this situation is acute and holds manifold consequences, particularly for the region’s primarily Indigenous residents. Based upon interviews and fieldwork in two Bering Sea communities and among regional weather forecasters, this paper explores the intertwined temporalities of weather, climate, and social life. I demonstrate that anticipatory culture, which otherwise structures anticipatory practices regarding climate, local weather, and social life, is beset by temporal dissonance across three timescales. First, dramatic climatic and ecosystem shifts reshape how Indigenous Peoples envision themselves as culturally inhabiting a long-range history and future. Second, changes in weather patterns, ecological cycles, and sea ice dynamics upset evaluations of seasonality, leading to a pervasive sense of unpredictability. Third, on the everyday timescale, social and technological change complicates mariners’ evaluations of risk and economic (commercial and subsistence) decision-making. I conclude by connecting these three socio-environmental temporalities to the temporal frames that primarily characterize weather and climate services, with an emphasis on the US National Weather Service. The paper discusses how such services may further orient toward engaging socially embedded practices of anticipation in addition to formal prediction. Such an orientation can help to shape an anticipatory culture that more closely aligns meteorological and social patterns.

Paths to resilience: the walleye pollock fleet uses multiple fishing strategies to buffer against environmental change in the Bering Sea

2018 ◽  
Vol 75 (11) ◽  
pp. 1977-1989 ◽  
Author(s):  
Jordan T. Watson ◽  
Alan C. Haynie
Keyword(s):  
Environmental Change ◽  
Water Temperature ◽  
Bering Sea ◽  
Walleye Pollock ◽  
Ecosystem Change ◽  
Socioeconomic Indicators ◽  
Fishing Strategies ◽  
The Us ◽  
Catch Rates ◽  
The Bering Sea

Fishers seek to maximize profits, so when choosing where to fish, they must consider interactions among the environment, costs, and fish prices. We examined catcher vessels in the US Bering Sea fishery for walleye pollock (Gadus chalcogrammus) (2003–2015) to characterize fisher responses to environmental change (e.g., abundance and water temperature). When pollock were abundant and the water warm, the fleet fished in similar locations. When temperatures were cooler or pollock abundance declined, two fishing strategies emerged, depending on the processor where a vessel delivered. One vessel group, whose catches were more likely to become fillets, often made shorter trips, requiring less fuel and time at sea. A second vessel group, whose catches were more likely to become surimi, traveled farther from port to regions with higher catch rates but generally smaller fish. By fishing in different locations to satisfy different markets, the fleet sustained revenues and buffered against environmental change. We identify a suite of socioeconomic indicators of the impacts of ecosystem change and illustrate that a one-vessel-fits-all approach may be insufficient for assessing the resilience of fleets.

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