Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8230
Title: Jellyfish, forage fish and the world's major fisheries
Author: Kelly L. Robinson, J. J. Ruzicka, Mary Beth Decker, Richard D. Brodeur, Frank L. Hernandez, E. M. Acha, Shin-Ichi Uye, Hermes Mianzan, W. M. Graham
Publication Year: 2014
Journal: Oceanography
Volume: 27
Issue: 4
Keywords: forage fish,jellyfish,Fisheries oceanography,predation,competition,food webs
Abstract: A majority of the worlds largest net-based fisheries target planktivorous forage fish that serve as a critical trophic link between the plankton and upper-level consumers such as large predatory fishes, sea birds, and marine mammals. Because the plankton production that drives forage fish also drive jellyfish production, these taxa often overlap in space, time, and diet in coastal ecosystems. This overlap likely also leads to predatory and competitive interactions as jellyfish are effective predators of fish early life stages and zooplankton. The trophic interplay between these groups is made more complex by the harvest of forage fish, which presumably releases jellyfish from competition and is hypothesized to lead to an increase in their production. To understand the role forage fish and jellyfish play as alternate energy transfer pathways in coastal ecosystems, we explore how functional group productivity is altered in three oceanographically distinct ecosystems when jellyfish are abundant and when fish harvest rates are reduced using ecosystem modeling. We propose that ecosystem-based fishery management approaches to forage fish stocks include the use of jellyfish as an independent, empirical ecosystem health indicator.
Theme: Ecosystem approach to improve management of marine resources
Foci: Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species.
Provide scientific support for the implementation of ecosystem-based management