Posts Tagged 'socio-economy'

Climate change: impact on marine ecosystems and world fisheries

I provide a selected survey of the literature on the effects of climate change on the biophysics and ecology of marine ecosystems and the fisheries that depend on them. First, I discuss the effects of warming, ocean acidification and deoxygenation on marine life. Second, I describe how the projected changes in the biophysics of the ocean is likely to affect the economics and management of ocean fisheries.

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Societal causes of, and responses to, ocean acidification

Major climate and ecological changes affect the world’s oceans leading to a number of responses including increasing water temperatures, changing weather patterns, shrinking ice-sheets, temperature-driven shifts in marine species ranges, biodiversity loss and bleaching of coral reefs. In addition, ocean pH is falling, a process known as ocean acidification (OA). The root cause of OA lies in human policies and behaviours driving society’s dependence on fossil fuels, resulting in elevated CO2 concentrations in the atmosphere. In this review, we detail the state of knowledge of the causes of, and potential responses to, OA with particular focus on Swedish coastal seas. We also discuss present knowledge gaps and implementation needs.

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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.

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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.

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For a world without boundaries: connectivity between marine tropical ecosystems in times of change

Tropical mangrove forests, seagrass beds, and coral reefs are among the most diverse and productive ecosystems on Earth. Their evolution in dynamic, and ever-changing environments means they have developed a capacity to withstand and recover (i.e., are resilient) from disturbances caused by anthropogenic activities and climatic perturbations. Their resilience can be attributed, in part, to a range of cross-ecosystem interactions whereby one ecosystem creates favorable conditions for the maintenance of its neighbors. However, in recent decades, expanding human populations have augmented anthropogenic activities and driven changes in global climate, resulting in increased frequencies and intensities of disturbances to these ecosystems. Many contemporary environments are failing to regenerate following these disturbances and consequently, large-scale degradation and losses of ecosystems on the tropical seascape are being observed. This chapter reviews the wealth of available literature focused on the tropical marine seascape to investigate the degree of connectivity between its ecosystems and how cross-ecosystem interactions may be impacted by ever-increasing anthropogenic activities and human-induced climate change. Furthermore, it investigates how disruption and/or loss of these cross-ecosystem interactions may impact the success of neighboring ecosystems and consequently, the highly-valued ecosystem services to which these ecosystems give rise. The findings from this review highlight the degree of connectivity between mangroves, seagrasses and coral reefs, and emphasizes the need for a holistic, seascape-wide research approach to successfully protect and preserve these critically important ecosystems and their associated services for future generations.

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Ocean acidification in the IPCC AR5 WG II

OUP book