STONY BROOK (US) — While helping to maintain the health of marine ecosystems, small forage fish contribute at least $16.9 billion annually to the worldwide fishing industry, a new study shows.
A first-time analysis estimates three kinds of contributions from small schooling species such as herring, anchovies, and sardines: direct catch, as food for other commercially important fish, and as a link in the food web in marine ecosystems, representing 20 percent of the global catch values of all marine fisheries combined.
Additionally, in 75 percent of the ecosystem models analyzed, at least one of the highly dependent predator species of forage fish, such as seabirds or marine mammals, depended on these fish for half or more of its diet, and in 30 percent of the models analyzed, forage fish made up three-quarters of the diet for at least one predator species.
A team of scientists examined these contributions of forage fish through a compilation and synthesis of 72 published Ecopath models from around the world. Ecopath models are a type of food web model that can be used to estimate the direction and strength of interactions among species within an ecosystem.
The analysis identified ecosystems that are likely to have highly to extremely dependent forage fish predators, which may assist in ecosystem-based management efforts that consider both commercial fisheries and effects to threatened or endangered species.
“In addition to their value to commercial fishing and other industries that depend on them for their products, forage fish play valuable roles in global ecosystems while they are still in the water,” says Ellen K. Pikitch, co-lead author and executive director of the Institute for Ocean Conservation Science and professor at Stony Brook University. “By quantifying the overall contributions forage fish make globally to both economies and ecosystems, we can evaluate the trade-offs of various uses of forage fish.”
The study, published online in the journal Fish and Fisheries, compiled data obtained from multiple independent studies of marine ecosystems around the world that include forage fish and showed the value of the direct catch of forage fish is $5.6 billion.
The highest forage fish catches were found in the Humboldt Current models where the Peruvian anchoveta fishery operates. The value of fisheries that are supported by forage fish is twice that of the direct catch at $11.3 billion.
The dollar amount of the contributions of forage fish to industries such as tourism and recreational fishing were not estimated for this study, and would increase the estimated economic value of the fish as prey species.
“Most previous economic studies of forage fish have focused primarily on their role as a directly harvested commodity,” says Konstantine J. Rountos, co-lead author and Ph.D. student at the School of Marine and Atmospheric Sciences at Stony Brook.
“By including an analysis of the indirect value these fish provide as prey species, this study provides data to policy makers, fishery managers, and others when making decisions about the harvest of these fish.”
“Considering the ecological roles and support services provided by forage fish in addition to their economic value can result in a win-win situation for both fisheries and ecosystems,” says Pikitch.
“This approach can result in sustainable populations of both forage fish and the larger fish that depend on them, as well as oceans teeming with a healthy balance of marine life.”
This research was supported by a grant from the Lenfest Ocean Program, and the research was conducted under the auspices of the Lenfest Forage Fish Task Force.
Source: Stony Brook University