LeMaRns: A Length-based Multi-species analysis by numerical simulation in R

Area of Science:

• Marine biology
• Fisheries science
• Ecological modeling

Background:

• Fish stocks exhibit complex interactions via predation and resource competition.
• Current fisheries management often overlooks these multi-species dynamics, focusing on single stocks.
• Existing multi-species models are frequently perceived as overly complex and lacking transparency for management application.

Purpose of the Study:

• To introduce LeMaRns, an R-package implementing the LeMans model for length-structured fish communities.
• To provide a simple, transparent, and accessible tool for incorporating multi-species interactions into fisheries management.
• To demonstrate the utility of LeMaRns in addressing key fisheries management challenges.

Main Methods:

• Development of LeMaRns, an R-package based on the general length-structured fish community model (LeMans).
• Characterization of fishing fleets by their gears and species catch preferences within the model.
• Application of the model to determine multi-species reference points, model mixed-fishery interactions, and analyze community indicator responses to fleet effort changes.

Main Results:

• LeMaRns provides a user-friendly implementation of a multi-species fish community model.
• The package facilitates the determination of multi-species reference points and the modeling of mixed-fishery dynamics.
• Demonstrated ability to examine community indicator responses to dynamic changes in fishing fleet effort.

Conclusions:

• LeMaRns offers a transparent, accessible, and efficient tool for fisheries managers.
• The package's open-source nature, comprehensive documentation, and ease of use are expected to increase its adoption.
• Facilitates a more holistic approach to fisheries management by accounting for multi-species interactions.