Collaborative research sheds light on the creation of climate-resilient multispecies fisheries
Around the world, there is considerable interest in developing fisheries management options that balance social, economic and ecological objectives for multispecies fisheries. Ideally, fisheries management should strive not only to produce good yields from single stocks, but also to avoid serial depletion and prevent the adverse effects of fishing on marine ecosystems – a difficult task. , but achievable. Although this task is even more difficult, as most fisheries catch multiple species. What are the options for multispecies fisheries? How can we balance the trade-offs between traditional single-species fishery management and other multi-species management options, while minimizing impacts on catches and benefits of target species?
In our new publication, scientists, academics and practitioners share case studies that address these questions, providing the opportunity to identify tools and pathways for managing multispecies fisheries that can be scaled up across the world.
What is multispecies fishing?
Multispecies fisheries often face greater sustainability challenges, and these challenges will increase in the face of climate change.
Many fisheries around the world capture multiple species, either as directed catches or as bycatch. The simultaneous capture of several species with differing productivity (i.e. the ability to grow and reproduce rapidly, and therefore to replenish future offspring) creates a risk that low productivity species will be depleted, altering the interactions between species and entire ecosystems. High productivity species that are more difficult to deplete (eg sardines or crabs) are more resilient and can persist even when fishing effort is high. As many single-species fisheries become more sustainable through science-based management strategies, multispecies fisheries often face greater sustainability challenges – and these challenges will increase in the face of climate change.
Multispecies fisheries can involve commercial, artisanal and recreational sectors and can be large, medium and small scale, often covering several landing sites. This complexity hinders monitoring and evaluation to establish science-based adaptive management for resilient multispecies fisheries, and endangers the food sources, jobs, profits and livelihoods and culture of coastal communities.
What is the solution?
A better question might be: why don’t the fisheries management approaches that are typically used with single-species fisheries work for multispecies fisheries? Some fisheries catch only one species – think of fishermen spearing tuna. Much of the theory and practice of fisheries science and management focuses on these types of fisheries. One approach to managing multispecies fisheries, which is actually quite common, is to simply pretend that we are managing one species, or focus management on one or two species, and ignore the rest. However, this approach may result in the serial depletion of higher trophic level stocks (e.g. groupers, snappers, sharks), and subsequent replacement by lower trophic level species (e.g. small pelagic fish, crustaceans, octopus ), which is also known as âfish along the food webâ. Serial depletion can not only lead to the collapse of the fishery, but also the collapse of the ecosystem. As a rule, large, tasty fish that grow slowly and are easy to catch are used up first; for example, groupers. Then the smaller, less visible fish are depleted, such as flatfish. Finally, fishing focuses on small pelagic fish, like sardines and invertebrates, but even these can be caught if the fishing pressure is extremely high. The answer is simply that single-species approaches do not take into account the complexity of the fishery and the fish caught.
In our research, we looked at seven different case studies. These include:
We explore how fisheries move from a single-species management mindset to implementing adaptive and climate-resilient multispecies fisheries management. Each of these fisheries has different levels of data richness, governance structure, and management resources, but shares the need to implement climate-resilient multispecies fisheries management plans. This collaborative research examines common challenges, tools and pathways used for the transition to climate resilient multispecies management.
Ultimately, the research identified various analytical tools and decision-making processes that support this transition, including:
- networks for communication and capacity building (e.g. learning networks, fishermen’s exchanges)
- Community fisheries surveillance
- bioeconomic modeling
- leadership and development programs for women fishermen
- recognition and use of traditional ecological knowledge
- and the approach of the fish baskets
The most common feature among the case studies is the use of participatory stakeholder processes.
What are fish baskets?
One of the ways to move away from the challenges of managing multispecies fisheries with a monospecies mindset is to consider the basket of fish approach.
With this approach, multispecies management is simplified. For example, a fishery that catches 200 species could be managed by assessing only 10 indicator species and maintaining responsibility for only 10 catch control measures to control fishing mortality, if all species can be grouped into 10 management baskets. .
After quickly estimating the relative vulnerability and current depletion / health status of all species in a multispecies fishery, the species are then sorted according to these two measures. This process creates initial management baskets of groups of species with similar characteristics of vulnerability and health status which then need to be refined by stakeholders depending on how the species are caught, where species are captured, tolerance to the risk of serial depletion, etc. Once stakeholders have determined the appropriate management baskets of groups of species for their fishery, they can choose an indicator species with a life history and vulnerability characteristics typical of the category, assess that species, set a target for fishing mortality for that species, then apply the same fishing mortality targeting the rest of the species in the category.
Using the fish basket approach and other approaches, the management of multispecies fisheries holds great promise for reducing or preventing serial depletion and associated negative impacts on social, economic and ecological fisheries performance objectives. enabling a more comprehensive understanding of the effects of fishing, climate and other stressors on the ecosystem.