February 19, 2016 — Scientists have long puzzled over what drives the reproductive success of Atlantic menhaden, a tiny but critical East Coast fish.
A new study, published in the ICES Journal of Marine Science and supported by the Lenfest Ocean Program, provides a partial answer: An oceanic climate cycle known as the Atlantic Multidecadal Oscillation, or AMO.
The finding is likely to be useful in improving the way scientists assess the species and the way managers set catch limits.
Menhaden is a small, oily fish that provides food for striped bass, bluefish, and several other species, as well as bait for fishermen.
It also is the target of the largest fishery on the East Coast, which is centred in Virginia and catches menhaden for use in nutritional supplements, animal feed, and fertilizer.
Setting catch limits has proved challenging, in part because no one has been able to say what drives recruitment—a technical term for how many young fish are produced. Recruitment largely determines how much fishing a population can sustain.
Tom Miller of the University of Maryland, and one of the authors of the study, explained that it is very difficult to understand and manage this stock.
To address this, the researchers used a statistical model designed for disorderly data like those on the abundance of young menhaden. They considered 16 factors that might be driving that abundance, including climatic cycles, intensity of fishing, temperature, salinity, and predator abundance.