Ecosystem-based fisheries management forestalls climate-driven collapse

Climate change is impacting fisheries worldwide with uncertain outcomes for food and nutritional security. Using management strategy evaluations for key US fisheries in the eastern Bering Sea we find that Ecosystem Based Fisheries Management (EBFM) measures forestall future declines under climate change over non-EBFM approaches. Yet, benefits are species-specific and decrease markedly after 2050. Under high-baseline carbon emission scenarios (RCP 8.5), end-of-century (2075–2100) pollock and Pacific cod fisheries collapse in >70% and >35% of all simulations, respectively. Our analysis suggests that 2.1–2.3 °C (modeled summer bottom temperature) is a tipping point of rapid decline in gadid biomass and catch. Multiyear stanzas above 2.1 °C become commonplace in projections from ~2030 onward, with higher agreement under RCP 8.5 than simulations with moderate carbon mitigation (i.e., RCP 4.5). We find that EBFM ameliorates climate change impacts on fisheries in the near-term, but long-term EBFM benefits are limited by the magnitude of anticipated change.

6. Applied ecology

‘Applied ecology’ looks at the application of ecological theories in modelling renewable resources and population dynamics, particularly in relation to species we wish to control or preserve. The collapse of cod fisheries shows the consequences when the bottom of the food chain (changes in phytoplankton) impacts the top. Changes in climate and fire regimes in America’s forests suggests current models may no longer be sustainable in future. How do species mixes help alleviate pressure from pests or pathogens? Successes in the lab have failed in the field, or not taken into account alternative problems that arise from manipulating the ecosystem. Biological and pest control strategies require a holistic approach.

Change in Atlantic cod migrations and adaptability of early land-based fishers to severe climate variation in the North Atlantic

ABSTRACTWe use biochemical, biological, archaeological, and historical analysis to examine relationships between Atlantic cod migration, sea temperature, and shifts in the distribution and occupancy of historical fishing sites in Iceland during the last millennium. Results support the hypothesis that the cooling climate of the North Atlantic during the period commonly referred to as the Little Ice Age coincided with changes in Atlantic cod migration patterns. Historical analysis shows a concomitant increase in reports of worsening Atlantic cod fishing and a severe decrease in domestic fishing, particularly in north Iceland. We conclude that Atlantic cod fisheries in Iceland originally thrived because of the proximity to cod migration routes. However, despite the mobility of local fishers, fluctuations in fish migrations, coupled with a harsher climate and increased competition for fishing grounds, resulted in a stagnation that lasted until the eventual modernization of the fishery in the mid-nineteenth century.

Effects of changes in stock productivity and mixing on sustainable fishing and economic viability

Within the new FMSY European paradigm, this paper shows how a combination of changes in fish stock mixing, non-stationarity in productivity, and constraints on unit stock concepts undermine the effective management of fisheries, especially when management reference points are not adjusted accordingly. Recent changes in stock structures, conditions and stock mixing between eastern and western Baltic cod can jeopardize the reliability of stock assessments and of the fishery economy. We modelled how different management, individual vessel decision-making, and stock growth and mixing scenarios have induced alternative individual vessel spatial effort allocation and economic performance by affecting fishing costs and by changing the relative stock abundance and size distribution. Stock mixing heavily influences profit and stock abundance for stocks that have experienced increased fishing mortality (F) levels. Western cod F has increased from a higher total allowed catches (TAC) advised in the medium-term due to the westward migration of eastern cod while eastern cod F has increased from reduced growth in the east. Greater pressures on western cod and decreased eastern cod growth and conditions greatly reduce the overall cod spawning stock biomass, thus changing the landing size composition and associated fishery profits. As a cumulative effect, fishing efforts are redirected towards western areas depending on management (quotas). However, total profits are less affected when traditional fishing opportunities and switching possibilities for other species and areas are maintained. Our evaluation indicates that current management mechanisms cannot correct for potential detrimental effects on cod fisheries when effort re-allocation changes landing origins. By investigating different economic starting conditions we further show that Baltic cod mis-management could have resulted in unintended unequal (skewed) impacts and serious consequences for certain fleets and fishing communities compared with others. Our management strategy evaluation is instrumental in capturing non-linear effects of different recommendations on sustainability and economic viability, and we show that fixed F-values management is likely not an attainable or sufficient goal in ensuring the sustainability and viability of fisheries and stocks given changing biological conditions.

Marine Fish Farming and the Blue Revolution: Culturing Cod Fisheries

The Blue Revolution promises to transform wild marine fish into docile domesticates, fish hunters into harvesters. As commercially fished marine species continue to face extinction in the wild due to over-fishing, pollution, global climate change and a host of other anthropo-genic assaults, ‘culture’ has emerged as a keyword in the field of marine fisheries management. Like the terrestrial dreams and grandiose visions of their Green comrades a half-century earlier, Blue revolutionaries advocate the application of scientific expertise, industrial technology and transnational capital in their oceanic culturing projects. These culturing projects influence and seek to transform human identity and ways of living as much as the genetic make-up, behaviours and metabolism of the wild fish species that are targeted for domestication.