Posts Tagged 'fisheries'

Bioeconomic analysis of the impact of ocean acidification associated with low recruitment of Isostichopus badionotus and implications for adaptive fishery management in the north of the Yucatan Peninsula, Mexico

The impact that ocean acidification (OA) could generate in the fisheries of Isostichopus badionotus at the north of the Yucatan Peninsulta, Mexico, was analysed by reducing the value of a parameter of the Beverton-Holt recruitment function, in accordance with the acidification scenarios of the Intergovermental Panel Panel on Climate Change (IPCC). The behaviour of the stock and the resulting fishery were analysed in a bioeconomic model structured by age, taking into account different market prices and fishing efforts. The results were compared in decision matrices that used the MiniMax and MaxMin criteria to determine the management strategy that best reduced the impact of  acidification. The largest stock reduction occurred during the first years of exploitation (B10>B15/BO) and all the variables that were considered did stabilize with time, reaching bioeconomic equilibrium. The worst scenario for not considering acidification occurred with low market prices, while the increase in price decreased the exploitation rate. The recruitment reduction determined the maximum effort that should have been applied; under such conditions it is recommended to operate an effort of 137 boats, considering the best market price.

Continue reading ‘Bioeconomic analysis of the impact of ocean acidification associated with low recruitment of Isostichopus badionotus and implications for adaptive fishery management in the north of the Yucatan Peninsula, Mexico’

AMAP assessment 2018: Arctic ocean acidification

Ocean acidification, resulting from changes in ocean chemistry induced by increasing seawater carbon dioxide concentrations, is one of the growing challenges to marine organisms, ecosystems and biogeochemical cycling. Some of the fastest rates of ocean acidification currently observed are in the Arctic Ocean, with important physiological and geochemical thresholds already surpassed. Projections indicate that large parts of the Arctic Ocean are undergoing marine carbonate system changes that will incur significant shifts in ecological status over the coming decades unless global carbon emissions are drastically curtailed. These changes in water chemistry and biology will have significant socio-ecological and economic consequences at the local to global level.

The first AMAP Arctic Ocean acidification report (AMAP, 2013) presented a scientific assessment on the changing state of ocean acidification in the Arctic and provided an Arctic-wide perspective on the rapid increase in seawater acidity. The report concluded that ocean acidification was affecting the Arctic marine environment and ecosystems.

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Projected impacts of future climate change, ocean acidification, and management on the US Atlantic sea scallop (Placopecten magellanicus) fishery

Ocean acidification has the potential to significantly impact both aquaculture and wild-caught mollusk fisheries around the world. In this work, we build upon a previously published integrated assessment model of the US Atlantic Sea Scallop (Placopecten magellanicus) fishery to determine the possible future of the fishery under a suite of climate, economic, biological, and management scenarios. We developed a 4x4x4x4 hypercube scenario framework that resulted in 256 possible combinations of future scenarios. The study highlights the potential impacts of ocean acidification and management for a subset of future climate scenarios, with a high CO2 emissions case (RCP8.5) and lower CO2 emissions and climate mitigation case (RCP4.5). Under RCP4.5 and the highest impact and management scenario, ocean acidification has the potential to reduce sea scallop biomass by approximately 13% by the end of century; however, the lesser impact scenarios cause very little change. Under RCP8.5, sea scallop biomass may decline by more than 50% by the end of century, leading to subsequent declines in industry landings and revenue. Management-set catch limits improve the outcomes of the fishery under both climate scenarios, and the addition of a 10% area closure increases future biomass by more than 25% under the highest ocean acidification impacts. However, increased management still does not stop the projected long-term decline of the fishery under ocean acidification scenarios. Given our incomplete understanding of acidification impacts on P. magellanicus, these declines, along with the high value of the industry, suggest population-level effects of acidification should be a clear research priority. Projections described in this manuscript illustrate both the potential impacts of ocean acidification under a business-as-usual and a moderately strong climate-policy scenario. We also illustrate the importance of fisheries management targets in improving the long-term outcome of the P. magellanicus fishery under potential global change.

Continue reading ‘Projected impacts of future climate change, ocean acidification, and management on the US Atlantic sea scallop (Placopecten magellanicus) fishery’

Global change in marine aquaculture production potential under climate change

Climate change is an immediate and future threat to food security globally. The consequences for fisheries and agriculture production potential are well studied, yet the possible outcomes for aquaculture (that is, aquatic farming)—one of the fastest growing food sectors on the planet—remain a major gap in scientific understanding. With over one-third of aquaculture produced in marine waters and this proportion increasing, it is critical to anticipate new opportunities and challenges in marine production under climate change. Here, we model and map the effect of warming ocean conditions (Representative Concentration Pathway scenario 8.5) on marine aquaculture production potential over the next century, based on thermal tolerance and growth data of 180 cultured finfish and bivalve species. We find heterogeneous patterns of gains and losses, but an overall greater probability of declines worldwide. Accounting for multiple drivers of species growth, including shifts in temperature, chlorophyll and ocean acidification, reveals potentially greater declines in bivalve aquaculture compared with finfish production. This study addresses a missing component in food security research and sustainable development planning by identifying regions that will face potentially greater climate change challenges and resilience with regards to marine aquaculture in the coming decades. Understanding the scale and magnitude of future increases and reductions in aquaculture potential is critical for designing effective and efficient use and protection of the oceans, and ultimately for feeding the planet sustainably.

Continue reading ‘Global change in marine aquaculture production potential under climate change’

Opportunities for climate‐risk reduction through effective fisheries management

Risk of impact of marine fishes to fishing and climate change (including ocean acidification) depend on the species’ ecological and biological characteristics, as well as their exposure to over‐exploitation and climate hazards. These human‐induced hazards should be considered concurrently in conservation risk assessment. In this study, we aim to examine the combined contributions of climate change and fishing to the risk of impacts of exploited fishes, and the scope for climate‐risk reduction from fisheries management. We combine fuzzy logic expert system with species distribution modeling to assess the extinction risks of climate and fishing impacts of 825 exploited marine fish species across the global ocean. We compare our calculated risk index with extinction risk of marine species assessed by the International Union for Conservation of Nature (IUCN). Our results show that 60% (499 species) of the assessed species are projected to experience very high risk from both overfishing and climate change under a “business‐as‐usual” scenario (RCP 8.5 with current status of fisheries) by 2050. The risk index is significantly and positively related to level of IUCN extinction risk (ordinal logistic regression, p < 0.0001). Furthermore, the regression model predicts species with very high risk index would have at least one in five (>20%) chance of having high extinction risk in the next few decades (equivalent to the IUCN categories of vulnerable, endangered or critically endangered). Areas with more at‐risk species to climate change are in tropical and subtropical oceans, while those that are at risk to fishing are distributed more broadly, with higher concentration of at‐risk species in North Atlantic and South Pacific Ocean. The number of species with high extinction risk would decrease by 63% under the sustainable fisheries‐low emission scenario relative to the “business‐as‐usual” scenario. This study highlights the substantial opportunities for climate‐risk reduction through effective fisheries management.

Continue reading ‘Opportunities for climate‐risk reduction through effective fisheries management’

Impacts of climate change on fisheries and aquaculture – synthesis of current knowledge, adaptation and mitigation options

The 2015 Paris Climate Agreement recognizes the need for effective and progressive responses to the urgent threat of climate change, through mitigation and adaptation measures, while taking into account the particular vulnerabilities of food production systems. The inclusion of adaptation measures in the fisheries and aquaculture sector is currently hampered by a widespread lack of targeted analyses of the sector’s vulnerabilities to climate change and associated risks, as well as the opportunities and responses available. This report provides the most up-to-date information on the disaggregated impacts of climate change for marine and inland fisheries, and aquaculture, in the context of poverty alleviation and the differential dependency of countries on fish and fishery resources.

Continue reading ‘Impacts of climate change on fisheries and aquaculture – synthesis of current knowledge, adaptation and mitigation options’

Consequences of spatially variable ocean acidification in the California Current: lower pH drives strongest declines in benthic species in southern regions while greatest economic impacts occur in northern regions

Highlights

• Impacts of ocean acidification change with latitude in the California Current.
• Vulnerable species (e.g., calcifying invertebrates) and their predators decline most.
• Decline in revenue projected, mainly from lower Dungeness crab catch in the north.
Abstract

Marine ecosystems are experiencing rapid changes driven by anthropogenic stressors which, in turn, are affecting human communities. One such stressor is ocean acidification, a result of increasing carbon emissions. Most research on biological impacts of ocean acidification has focused on the responses of an individual species or life stage. Yet, understanding how changes scale from species to ecosystems, and the services they provide, is critical to managing fisheries and setting research priorities. Here we use an ecosystem model, which is forced by oceanographic projections and also coupled to an economic input-output model, to quantify biological responses to ocean acidification in six coastal regions from Vancouver Island, Canada to Baja California, Mexico and economic responses at 17 ports on the US west coast. This model is intended to explore one possible future of how ocean acidification may influence this coastline. Outputs show that declines in species biomass tend to be larger in the southern region of the model, but the largest economic impacts on revenue, income and employment occur from northern California to northern Washington State. The economic consequences are primarily driven by declines in Dungeness crab from loss of prey. Given the substantive revenue generated by the fishing industry on the west coast, the model suggests that long-term planning for communities, researchers and managers in the northern region of the California Current would benefit from tracking Dungeness crab productivity and potential declines related to pH.

Continue reading ‘Consequences of spatially variable ocean acidification in the California Current: lower pH drives strongest declines in benthic species in southern regions while greatest economic impacts occur in northern regions’


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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book