Changing how we approach fisheries: A first attempt at an operational framework for ecosystem approaches to fisheries management

Abstract

The increasing need to account for the many factors that influence fish population dynamics, particularly those external to the population, has led to repeated calls for an ecosystem approach to fisheries management (EAFM). Yet systematically and clearly addressing these factors, and hence implementing EAFM, has suffered from a lack of clear operational guidance. Here, we propose 13 main factors (shift in location, migration route or timing, overfishing (three types), decrease in physiology, increase in predation, increase in competition, decrease in prey availability, increase in disease or parasites and a decline in habitat quality or habitat quantity) that can negatively influence fish populations via mechanisms readily observable in ~20 population features. Using these features as part of a diagnostic framework, we develop flow charts that link probable mechanism(s) underlying population change to the most judicious management actions. We then apply the framework for example case studies that have well‐known and documented population dynamics. To our knowledge, this is the first attempt to provide a clearly defined matrix of all the probable responses to the most common factors influencing fish populations, and to examine possible diagnostics simultaneously, comparatively and relatively in an attempt to elucidate the most probable mechanisms responsible. The framework we propose aims to operationalize EAFM, thereby not only better diagnosing factors influencing fish populations, but also suggesting the most appropriate management interventions, and ultimately leading to improved fisheries. We assert the framework proposed should result in both better use of limited analytical and observational resources and more tailored and effective management actions.

Management of transboundary and straddling fish stocks in the Northeast Atlantic in view of climate‐induced shifts in spatial distribution

“…Measures adopted at the global or regional level have been incorporated in national legislation and management. During the last few decades, ecosystem considerations have been increasingly emphasized and will gradually be incorporated in fisheries management (Gullestad et al, 2017;Link, Huse, Gaichas, & Marshak, 2020;Skern-Mauritzen et al, 2016). Related measures can be seen in the adoption of a number of area closures in international waters to protect vulnerable marine ecosystems (VMEs) (NEAFC;…”

“…It could be argued that this mutual dependence has a dampening effect on conflicts regarding allocation. During the last few decades, ecosystem considerations have been increasingly emphasized and will gradually be incorporated in fisheries management (Gullestad et al., 2017; Link, Huse, Gaichas, & Marshak, 2020; Skern‐Mauritzen et al., 2016). Related measures can be seen in the adoption of a number of area closures in international waters to protect vulnerable marine ecosystems (VMEs) (NEAFC; Table S2) or the introduction of regulations to protect vulnerable by‐catch species, for example sharks (Ellis et al., 2008).…”

A Case Study in Connecting Fisheries Management Challenges With Models and Analysis to Support Ecosystem-Based Management in the California Current Ecosystem

“…In addition, Comment 10 highlights the need to assess the links between changes in prey availability over space and predator distribution (Table 1). Understanding spatiotemporal overlap between predators and potential prey species is particularly important for the development of a more ecosystem-focused approach to fisheries management (Carroll et al, 2019;Link et al, 2020). A number of negative ecological and economic events occurring within the CCE in recent years, including, but not limited to, unusual mortality events for sea lions and seabirds (Wells et al, 2013), and unprecedented whale entanglements (Santora et al, 2020), were the result of changes in predator distribution linked to changes in forage availability and unprecedented environmental conditions.…”

Quantitative molecular detection of larval Atlantic herring (Clupea harengus) in stomach contents of Atlantic mackerel (Scomber scombrus) marks regions of predation pressure

“…It is a key challenge to understand the mechanisms underlying the high variability in larval mortality for managing this valuable marine resource and key ecosystem component. This issue is especially important in management strategy evaluations (MSE) (see 31 and references therein). Generally, the ability to predict future standing stock biomass is dependent on in-depth knowledge about mechanisms underlying recruitment success (e.g.…”