Tradeoffs of managing cod as a sustainable resource in fluctuating environments

Sustainable human exploitation of living marine resources stems from a delicate balance between yield stability and population persistence to achieve socioeconomic and conservation goals. But our imperfect knowledge of how oceanic oscillations regulate temporal variation in an exploited species can obscure the risk of missing management targets. We illustrate how applying a management policy to suppress fluctuations in fishery yield in variable environments (prey density and regional climate) can present unintended outcomes in harvested predators and the sustainability of harvesting. Using Atlantic cod (Gadus morhua, an apex predatory fish) in the Barents Sea as a case study we simulate age-structured population and harvest dynamics through time-varying, density-dependent and density-independent processes with a stochastic, process-based model informed by 27-year monitoring data. In this model, capelin (Mallotus villosus, a pelagic forage fish), a primary prey of cod, fluctuations modulate the strength of density-dependent regulation primarily through cannibalistic pressure on juvenile cod survival; sea temperature fluctuations modulate thermal regulation of cod feeding, growth, maturation, and reproduction. We first explore how capelin and temperature fluctuations filtered through cod intrinsic dynamics modify catch stability and then evaluate how management to suppress short-term variability in catch targets alters overharvest risk. Analyses revealed that suppressing year-to-year catch variability impedes management responses to adjust fishing pressure, which becomes progressively out of sync with variations in cod abundance. This asynchrony becomes amplified in fluctuating environments, magnifying the amplitudes of both fishing pressure and cod abundance and then intensifying the density-dependent regulation of juvenile survival through cannibalism. Although these transient dynamics theoretically give higher average catches, emergent, quasicyclic behaviors of the population would increase long-term yield variability and elevate overharvest risk. Management strategies that overlook the interplay of extrinsic (fishing and environment) and intrinsic (life history and demography) fluctuations thus can inadvertently destabilize fish stocks, thereby jeopardizing the sustainability of harvesting. These policy implications underscore the value of ecosystem approaches to designing management measures to sustainably harvest ecologically connected resources while achieving socioeconomic security.publishedVersio

Advice on fishing opportunities for Northeast Arctic cod in 2023 in ICES subareas 1 and 2

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Report of the Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG) 2022

On 30 th March 2022 all Russian participation in ICES was temporally suspended. Although the announcement of the suspension stressed the role of ICES as a “multilateral science organization”, this suspension applied not only to research activities, but also to the ICES work providing fisheries advice for the sustainable management of fish stocks and ecosystems. As a result of the suspension, the ICES AFWG provided advice only for saithe, coastal cod north, coastal cod south, and golden redfish ( Sebastes norvegicus ). Northeast Arctic (NEA) cod, haddock and beaked redfish ( Sebastes mentella ) assessments have been conducted outside of ICES in a newly constituted Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG). Although this work has been conducted independently of ICES, the methodologies agreed at ICES benchmarks and agreed HCRs (Harvest Control Rules) have been followed in providing this advice.publishedVersio

Advice on fishing opportunities for beaked redfish in 2023 and 2024 in ICES subareas 1 and 2

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Advice on fishing opportunities for Northeast Arctic haddock in 2023 in ICES subareas 1 and 2

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Advice on fishing opportunities for Northeast arctic haddock in 2024 in ICES subareas 1 and 2

Stock Name: Northeast Arctic haddock (ICES areas 1 and 2) The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the Joint Norwegian–Russian Fisheries Commission management plan is applied, catches in 2024 should be no more than 127 550 tonnes.publishedVersio

Advice on fishing opportunities for Greenland halibut in 2024 in ICES subareas 1 and 2

Stock Name: Northeast Arctic Greenland halibut (ICES areas 1 and 2) The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the MSY approach is applied, catches in 2024 should be no more than 15 560 tonnes.publishedVersio

Report of the Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG) 2023

On 30 th March 2022 all Russian participation in ICES was temporally suspended. Although the announcement of the suspension stressed the role of ICES as a “multilateral science organization”, this suspension applied not only to research activities, but also to the ICES work providing fisheries advice for the sustainable management of fish stocks and ecosystems. As a result of the suspension, the ICES AFWG provided advice only for saithe, coastal cod north, coastal cod south, and golden redfish ( Sebastes norvegicus ). Northeast Arctic (NEA) cod, haddock and Greenland halibut assessments have been conducted outside of ICES in a newly constituted Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG). Although this work has been conducted independently of ICES, the methodologies agreed at ICES benchmarks and agreed HCRs (Harvest Control Rules) have been followed in providing this advice. The Greenland halibut model has been revised at an ICES benchmark in 2023. The JRN-AFWG has agreed to use the new ICES model, with the addition of revising the Russian survey tuning index (as was recommended at the benchmark). Although the overall biomass level in the model has been revised, the trends and advice are similar to the old model. The Greenland halibut advice is for one year to bring the timing back in line with the slope survey, after this a two-year advice cycle will resume. The main worry with that stock is a history of TACs and catches well above advice. Given that the model is now indicating that the stock will drop below B pa by the end of 2023, continuing to set quota above advice poses a risk of serious harm to the stock.publishedVersio

Advice on fishing opportunities for Northeast Arctic cod in 2024 in ICES subareas 1 and 2

Stock Name: Northeast Arctic cod (ICES areas 1 and 2) The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the Joint Norwegian–Russian Fisheries Commission management plan is applied, catches in 2024 should be no more than 453 427 tonnes.publishedVersio