Combining Ecosystem and Single-Species Modeling to Provide Ecosystem-Based Fisheries Management Advice Within Current Management Systems

Daniel Howell,Matthew Cieri,Andre Buchheister,Amy M Schueller,Howard Townsend,Mathieu G Lundy,David Chagaris,David G Reid,Katie Drew,Jacob W Bentley,Debbi Pedreschi

doi:10.3389/fmars.2020.607831

Abstract

Although many countries have formally committed to Ecosystem-Based Fisheries Management (EBFM), actual progress toward these goals has been slow. This paper presents two independent case studies that have combined strategic advice from ecosystem modeling with the tactical advice of single-species assessment models to provide practical ecosystem-based management advice. With this approach, stock status, reference points, and initial target F are computed from a single-species model, then an ecosystem model rescales the target F according to ecosystem indicators without crossing pre-calculated single-species precautionary limits. Finally, the single-species model computes the quota advice from the rescaled target F, termed here Feco. Such a methodology incorporates both the detailed population reconstructions of the single-species model and the broader ecosystem perspective from ecosystem-based modeling, and fits into existing management schemes. The advocated method has arisen from independent work on EBFM in two international fisheries management systems: (1) Atlantic menhaden in the United States and (2) the multi species fisheries of the Irish Sea, in the Celtic Seas ecoregion. In the Atlantic menhaden example, the objective was to develop ecological reference points (ERPs) that account for the effect of menhaden harvest on predator populations and the tradeoffs associated with forage fish management. In the Irish Sea, the objective was to account for ecosystem variability when setting quotas for the individual target species. These two exercises were aimed at different management needs, but both arrived at a process of adjusting the target F used within the current single-species management. Although the approach has limitations, it represents a practical step toward EBFM, which can be adapted to a range of ecosystem objectives and applied within current management systems.

Highlights

Incorporating ecosystem information into fisheries management [i.e., Ecosystem Approach to Fisheries Management (EAFM) and Ecosystem-Based Fisheries Management (EBFM)] is an acknowledged goal of many nations based upon an agreed code of conduct for responsible fisheries management (FAO, 1995, FAO, 2008, NOAA, 2016)
As fisheries management agencies evolve toward EBFM, the modeling approaches used to inform decision-making must evolve
Combined single-species with ecosystem or multispecies modeling tools can address the standard fisheries management objectives as well as a broader suite of ecosystem-oriented objectives that arise with increased EBFM implementation

Summary

INTRODUCTION

Incorporating ecosystem information into fisheries management [i.e., Ecosystem Approach to Fisheries Management (EAFM) and Ecosystem-Based Fisheries Management (EBFM)] is an acknowledged goal of many nations based upon an agreed code of conduct for responsible fisheries management (FAO, 1995, FAO, 2008, NOAA, 2016). We present two independent case studies that provided tactical management advice through the combined use of EwE models and single species assessments in two different settings: (1) Atlantic menhaden on the East Coast of the United States (Anstead et al, 2020; Drew et al, 2020; Chagaris et al, this volume) and (2) commercial fish stocks in the Irish Sea (Bentley et al, this volume) In both cases, an approach was developed which allowed ecosystem modeling results to be incorporated into the existing management structure, while retaining the single species assessment models used to support existing management.

THE METHOD

SUMMARY

DATA AVAILABILITY STATEMENT