A Review of economic analysis of climate change impacts and adaptation in fisheries and aquaculture

Focusing on economic methods, this study provides a comprehensive review of the current research in fisheries and aquaculture within the context of climate change. We find there has been remarkable progress in evaluating the biophysical impacts of climate change on fish. However, the effect those impacts have on future fish stocks, yields, and dynamics are less understood. Climate change adaptation strategies in fisheries and aquaculture lack quantitative assessment, while current vulnerability indices rely heavily on subjective weighting schemes. Economic studies involving fisheries and aquaculture have seen some recent advancements but can be improved through incorporating methods from other disciplines, notably agricultural economics. Relative to its increasingly large role in global fish supply, the aquaculture sector is found to be under-represented in the economic literature. We suggest that future research in fisheries and aquaculture should further incorporate methods from agricultural economics, focus on the economics of aquaculture, and refine interdisciplinary research methods such as bioeconomic modelling.

Climate change or mismanagement?

Climate change and deoxygenation are affecting fish stocks on a global scale, but disentangling the impacts of these stressors from the effects of overfishing is a challenge. This study was conducted to distinguish between climate change and mismanagement as possible causes for the drastic decline in spawning stock size and reproductive success in cod (Gadus morhua) and herring (Clupea harengus) in the Western Baltic Sea, when compared with the good or satisfactory status and reproductive success of the other commercial species in the area. Available data on water temperature, wind speed, and plankton bloom during the spawning season did not reveal conclusive correlations between years with good and bad reproductive success of cod or herring. Notably, the other commercial species in the area have very similar life history traits suggesting similar resilience against stress caused by climate change or fishing. The study concludes that severe, sustained overfishing plus inappropriate size selectivity of the main fishing gears have caused the decline in spawning stock biomass of cod and herring to levels that are known to have a high probability of impaired reproductive success. It is pointed out that allowed catches were regulated by management and adhered to by the fishers, meaning that unregulated fishing did not occur. Thus, mismanagement (quotas that were too high and gears that selected too small sizes) and not climate change appears to be the primary cause of the bad status of cod and herring in the Western Baltic Sea.

Trawl impacts on the relative status of biotic communities of seabed sedimentary habitats in 24 regions worldwide

Bottom trawling is widespread globally and impacts seabed habitats. However, risks from trawling remain unquantified at large scales in most regions. We address these issues by synthesizing evidence on the impacts of different trawl-gear types, seabed recovery rates, and spatial distributions of trawling intensity in a quantitative indicator of biotic status (relative amount of pretrawling biota) for sedimentary habitats, where most bottom-trawling occurs, in 24 regions worldwide. Regional average status relative to an untrawled state (=1) was high (>0.9) in 15 regions, but <0.7 in three (European) regions and only 0.25 in the Adriatic Sea. Across all regions, 66% of seabed area was not trawled (status = 1), 1.5% was depleted (status = 0), and 93% had status > 0.8. These assessments are first order, based on parameters estimated with uncertainty from meta-analyses; we recommend regional analyses to refine parameters for local specificity. Nevertheless, our results are sufficiently robust to highlight regions needing more effective management to reduce exploitation and improve stock sustainability and seabed environmental status—while also showing seabed status was high (>0.95) in regions where catches of trawled fish stocks meet accepted benchmarks for sustainable exploitation, demonstrating that environmental benefits accrue from effective fisheries management. Furthermore, regional seabed status was related to the proportional area swept by trawling, enabling preliminary predictions of regional status when only the total amount of trawling is known. This research advances seascape-scale understanding of trawl impacts in regions around the world, enables quantitative assessment of sustainability risks, and facilitates implementation of an ecosystem approach to trawl fisheries management globally.

The ambiguous impacts of alternative livelihoods on fisher wellbeing in a closed access fish sanctuary in Port Antonio, Jamaica

Alternative livelihood programs are a central feature of contemporary conservation planning that aim to aid efforts to reduce pressure on natural resources and avoid, minimize, or mitigate the impacts of conservation on the wellbeing of local stakeholders. Evidence of the effectiveness of these programs is, however, decidedly mixed. This research examines the relationship between livelihoods, conservation, and wellbeing among nearshore fishers in Port Antonio, Jamaica, in the context of a recently established marine no-take area. The East Portland Fish Sanctuary was established in 2016 with the aim of supporting the recovery of depleted nearshore fish stocks, marine habitats, and mitigating impacts on local communities and fishers through a range of activities. Mitigation of impacts included efforts to shift pressure from overexploited nearshore fish stocks to offshore resources and to provide support to fishers for training and opportunities to earn income in the tourism sector. The results suggest that additional sources of income tended to enhance the wellbeing of fishers across several dimensions but that it also contributed to additional pressure on nearshore resources. Furthermore, neither tourism nor offshore fishing appear to be particularly promising in terms of their ability to deliver “win-win” outcomes for conservation and wellbeing. Instead, the results suggest that the impacts of different types of alternative livelihoods on conservation and wellbeing are highly variable and perhaps that efforts should be redirected to supporting efforts to provide suitable and acceptable alternatives to spearfishing which appears to have one of the largest overall impacts on individual harvest rates.

Sustainable management of a marine protected area in Vietnam: An application of visitors’ willingness to pay for conservation in Cu Lao Cham

As an important area in terms of biodiversity and fish stocks in Vietnam, Cu Lao Cham or Cham Islands (CLC) marine protected area (MPA) is under increasing threat from human activities. Conservation efforts have recently been implemented but economic analysis of the CLC MPA’s natural values did not investigate what may affect policy decisions on CLC MPA’s sustainable development. Using a structured questionnaire and a payment card technique (based on the contingent valuation method), we estimate visitors’ willingness to pay (WTP) for conservation of marine resources in the CLC MPA. The log-normal regression results indicate that the visitors’ WTP for conservation is affected by their characteristics, perceptions of environmental protection and conservation, and their assessment of the current CLC MPA entrance fee. Visitors are WTP an additional amount of US$2.26 per person for conservation while visiting the CLC MPA. This indicates that with the introduction of the proposed entrance fee (the mean WTP added to the current entrance fee), the CLC MPA management would not only have sufficient funds for their management and conservation programmes, but also that the number of visitors may decline slightly, which would reduce some of the pressure on the environment, natural resources, and coral reefs.

Jockeying for Position

The Falklands War was a reminder that naval conflict could mean massive restrictions on the use of the oceans. Meanwhile, few Western countries ratified the Convention in the decade after it was finalized. With the Convention stalled, the United States conducted “freedom of navigation” operations to ensure that countries did not claim more of the oceans than Washington thought legal. US operations led to a clash with Libya and a confrontation with the Soviet Union. Other countries focused on sharpening claims to islands, which could give governments rights to nearby waters. At the same time, pressure grew on countries to grapple with overfishing. The costs of unrestricted high-seas fishing became evident in the Bering Sea, where a multinational fleet exhausted fish stocks. The thawing of the Cold War led to diplomatic breakthroughs on both high-seas fishing and seabed mining, paving the way for large-scale ratifications of the Convention.

Fish provision in a changing environment: The buffering effect of regional trade networks

Local and regional trade networks in small-scale fisheries are important for food security and livelihoods across the world. Such networks consist of both economic flows and social relationships, which connect different production regions to different types of fish demand. The structure of such trade networks, and the actions that take place within them (e.g., people fishing, buying, selling), can influence the capacity of small-scale fisheries to provide sufficient fish in a changing social and ecological context. In this study, we aim to understand the importance of networks between different types of traders that access spatially-distinct fish stocks for the availability and variability of fish provision. We deployed a mixed-methods approach, combining agent-based modelling, network analysis and qualitative data from a small-scale fishery in Baja California Sur, Mexico. The empirical data allowed us to investigate the trade processes that occur within trade networks; and the generation of distinct, empirically-informed network structures. Formalized in an agent-based model, these network structures enable analysis of how different trade networks affect the dynamics of fish provision and the exploitation level of fish stocks. Model results reveal how trade strategies based on social relationships and species diversification can lead to spillover effects between fish species and fishing regions. We found that the proportion of different trader types and their spatial connectivity have the potential to increase fish provision. However, they can also increase overexploitation depending on the specific connectivity patterns and trader types. Moreover, increasing connectivity generally leads to positive outcomes for some individual traders, but this does not necessarily imply better outcomes at the system level. Overall, our model provides an empirically-grounded, stylized representation of a fisheries trading system, and reveals important trade-offs that should be considered when evaluating the potential effect of future changes in regional trade networks.