Quantifying the Trophic Importance of Gulf Menhaden Brevoortia Patronus within the Northern Gulf of Mexico Ecosystem

Gulf menhaden, Brevoortia patronus, are frequently cited as playing a predominant role in the trophic structure of the northern Gulf of Mexico (nGOM) ecosystem; yet, much work remains in quantifying its ecological importance. We perform a meta-analysis of 568 diet studies, 136 of which identify predator-prey interactions involving Gulf menhaden or Brevoortia sp. A total of 78 species were reported to consume menhaden, with no significant difference detected between the Atlantic Ocean and the GOM in the mean occurrence of Brevoortia spp. in all predator stomachs. Using a probabilistic approach, the estimated dietary contribution of identifiable menhaden to all predators generally ranged between 2-3%, with the largest contribution identified for blacktip shark Carcharhinus limbatus (8%) and lower estimates (<2%) obtained for oceanic sharks, billfish, and tunas. When diet compositions were corrected for unidentified prey by the proportion of fish species biomass in the ecosystem, five predators showed a relatively large dependence on menhaden prey: juvenile king Scomberomorus cavalla and Spanish mackerel S. maculatus, adult Spanish mackerel, red drum Sciaenops ocellatus, and blacktip shark. The quantification of trophic linkages and key predators identified herein is vital to future ecosystem modeling efforts within and management of the nGOM.