Ecosystem approach to sardine fisheries management

Aim

Develop a Management Plan for purse seine fishing aligned with the guidelines of the Common Fisheries Policy and the Marine Strategy Framework Directive, based on the principles of sustainability of fisheries resources, revitalization of the biodiversity of the pelagic habitat and optimized exploitation considering the economic profitability of the sector.

About the project

Given the conservation status of the Iberian sardine stock, considered to be in poor environmental condition in the last MSFD assessment, due to recruitments as low as historical minimums, the need to deepen scientific knowledge regarding the biology and ecology of this species was recognized and of the species that interact with it and are exploited jointly by purse seine fishing. In particular, to study the influence of environmental conditions and anthropogenic pressures (including fisheries) on the species and on the ecosystem in order to reduce uncertainty in abundance predictions and optimize the exploitation of these resources, while simultaneously minimizing the negative impact of pressures on the biodiversity of coastal habitats, particularly in the preferential nursery and spawning areas of pelagic fish. These last aspects are included in several European Directives, in addition to the CFP, of which Europe 2020 and the Marine Strategy Framework Directive (MSFD) stand out.

Specific objectives

• Identify the discriminating environmental variables for the biology, distribution, abundance and recruitment of coastal pelagic fish (sardines, horse mackerel, mackerel and anchovy) and develop models that allow the study and prediction of that influence;
• Determine sardine mortality, growth and reproduction rates in function with the variation of oceanographic variables, food availability, trophic interaction and the influence of parasites and pollutants, which will be used to parameterize the various models;
• Determine the distribution, identity and connectivity of populations from a multispecific and ecosystemic perspective and develop ecosystem models to assess the impact of interspecific relationsships and of fisheries on a joint dynamics of pelagic fish stocks;
• Characterize the social, economic and biological components of the purse seine fishery and the canning industry and assess the interaction and mutual influence between the various components;
• Assess stocks and determine biological reference points for the main species of the pelagic community of the Portuguese coast, focusing on those of greatest importance for purse seine fishery, such as chub mackerel and anchovy.

Project Actions

Habitat and life cycle

The variability of oceanographic conditions, such as temperature, salinity, currents and food availability, are considered the main factors that influence the dynamics of small pelagic populations, affecting larval survival and dispersal and also the reproductive potential of adults. A more in-depth knowledge of the mechanisms that govern these fluctuations is necessary in order to be able to contribute for an effective management of the populations of Iberian pelagic fish, in particular sardine.

A2. Physical environment and productivity

Identify the most important environmental variables for the dynamics of small pelagic fish and obtain time series of environmental data that allow modeling and predicting that influence.

A3. Natural mortality

Obtain mortality rates at different stages of development (from eggs to adults) of pelagic fish in function of the variation of oceanographic parameters, food availability, predation and contaminants.

A4. Growth and reproduction

Study the effect of the variation of environmental variables considered most relevant on the growth and reproduction of pelagic fish.

Population dynamics and fisheries

In order to develop a bio-economic and multi-specific plan for the management of the purse seine fishery, it is necessary to determine the distribution and assess the abundance of the various exploited species, identify synchronicities and alternations and assess their impact both in terms of employment and income value. It is also necessary to understand how the social and economic component affects the biological component and vice versa. Knowing the synchronicities and the factors that determine them will allow making predictions that will help fisheries and industry to adapt their exploitation patterns and maximize their income.

A5. Abundance, Distribution and Connectivity

Improve estimates of pelagic species from acoustic campaigns from an ecosystemic perspective. Determine the influence of environmental factors on the distribution, abundance and structure of the pelagic community. Study the connectivity of sardine populations and re-evaluate the identity of Atlantic population units.

A6. Fishing Activity and Production

Improve knowledge about the social, economic, technological and biological components of the purse seine fishery and the associated canning industry, and understand the interaction between the various components. Collaborate with the fisheries sector in validating data, implementing experiences on board commercial vessels, discussing the feasibility of technical measures.

A7. Population and Ecosystem Dynamics

Assess the stocks of the main pelagic species on the Portuguese coast, using approaches and models appropriate to the biology and quality of the data available for each species. For sardine, a species with good biological monitoring, advance in population modeling incorporating environmental effects and spatial dynamics of populations and fisheries.

A8. Management Models and Plans

Develop a Management Plan for the purse seine fishery aligned with the guidelines of the current PCP, based on the principles of sustainability of fishing resources, optimized exploitation considering the maximum sustainable catch, and economic profitability of the sector, with reduced impact concerning the ecosystem. Estimate Biological Reference Points (BRPs), fundamental guides to evaluate the performance of harvest control rules that may be selected following the interaction with the stakeholders. Develop a bio-economic model for the optimal exploitation of the resource that will allow the design of new harvest control rules considering simultaneously the economic profitability of the activity and the sustainability of the population.