Inclusion of jellyfish in 30+ years of Ecopath with Ecosim models

Philip D Lamb,Thomas K Doyle,Martin I Taylor,Ewan Hunter,Simon Creer,John K Pinnegar,Marta Coll

doi:10.1093/icesjms/fsz165

Abstract

Abstract A review of the functional role of jellyfish in Ecopath with Ecosim (EwE) models by Pauly et al. [Pauly, D., Graham, W., Libralato, S., Morissette, L., and Deng Palomares, M. L. 2009. Jellyfish in ecosystems, online databases, and ecosystem models. Hydrobiologia, 616: 67–85.] a decade ago concluded that recreation of jellyfish population dynamics in models required additional ecological research and the careful consideration of their unique biology during model construction. Here, amidst calls for ecosystem-based management and the growing recognition of jellyfishes' role in foodwebs, we investigate how jellyfish are implemented in EwE models and identify areas requiring improvement. Over time, an increasing percentage of models have included jellyfish. Jellyfish were often linked to the wider ecosystem, with many predators and prey included in models. However, ecotrophic efficiency, a measure of the extent to which they are used by higher trophic levels, was frequently set at low values, suggesting that jellyfish are still perceived as under-utilized components of the ecosystem. Moving forward, greater care should be taken to differentiate the functional roles played by ctenophores, cnidarians, and pelagic tunicates. Additionally, when feasible, early life stages should be incorporated as multi-stanza groups to more accurately depict jellyfishes' complex life cycle.

Highlights

Keeping marine ecosystems resilient and healthy is a conservation, economic development, and food security goal
The inclusion of jellyfish groups in Ecopath with Ecosim (EwE) models has increased over time and is characterized by three periods: 1984– 2000, 2000–2007, and 2007-present (Figure 1)
Jellyfish groups are represented in a wide variety of ecosystem models around the world, there is a concentration of research in North America and Europe, with fewer models seen in the other continents (Figure 2)

Summary

Introduction

Keeping marine ecosystems resilient and healthy is a conservation, economic development, and food security goal. The sustainability of fish stocks is dependant on careful management of catches, and factors such as the preservation of foodweb linkages that underpin fish stocks and the ecologically-compatible implementation of other human activities in the marine environment (Pitcher et al, 2009). Ecosystembased management (EBM) incorporates many of these considerations and is thought to be essential to the future health of fish stocks. Whole-ecosystem models can play an important role towards achieving EBM by providing a framework to quantify interspecific interactions. They can facilitate the exploration of alternative ecosystem states, improve our understanding of the ecosystem

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