SCORE Research

Scientific analysis of the efficacy of stocking marine organisms

A century after fishery managers began stocking hatchery-reared organisms into the sea, the first studies of the effectiveness of stocking marine fishes and invertebrates began to be published in peer-reviewed scientific journals by scientists in Japan (Tsukamoto et al., 1989), Norway (Svåsand et al., 1990; Svåsand and Kristiansen, 1990a, b; Kristiansen and Svåsand, 1990) and the USA (Beal, 1991). These studies were, perhaps, sparked about a decade earlier by the first published studies of the fate of salmon stocked into rivers (Hager and Noble, 1976; Bilton et al., 1982). With these pioneering studies, the science of marine stock enhancement began to emerge. Scientific inquiry about marine stock enhancement has increased steadily since then. As the number of fishery scientists conducting research in this field increases, answers to some of the key questions about the efficacy of stocking are beginning to emerge.

As we start to move beyond the fact finding stage in this new field of science, emphasis is now being placed on developing economically effective and environmentally sound stock enhancement strategies. SCORE scientists and colleagues around the world are evaluating working hypotheses about stocking, examining the "questions of the day" and coupling fishery science and aquaculture science to explore opportunities, understand limitations, and develop recipes for success.

Too much emphasis on research? Why do we need more research if we already can produce the fish and stock mass quantities?

Stocking hatchery-reared organisms without taking inventory of which ones contributed to abundance and which ones didn't, and without using that information to adjust stocking strategies is akin to managing a stock portfolio without looking at the recent performance of the various stock options available. As investors need to know the potential of various stock options, so too do fishery managers need to know which stocking options and strategies provide high probability of good returns and which ones absolutely do not. Many stakeholders who support stocking programs do not realize that performance of the stocked organisms has generally not been evaluated nor understood. Most think that stock enhancement is is a finely tuned science. Yet at this point in time little is actually known about how to make stocking perform as an effective fishery management tool, because so few stakeholders and so few scientists have made this issue a high enough priority to focus their attention on it. If this technology has great, but underdeveloped, potential to rapidly recover depleted fish populations and enhance recruitment-limited stocks, then we need to explore it and develop sound economic and environmental policies that can help ensure that stocking is an effective and efficient tool for recovering stocks and increasing abundance.

This is why SCORE was established. Planning and executing research to resolve critical uncertainties in this field and establish more responsible stocking protocols, combined with quantitative modeling to provide insight about actual potential, is the strongest way to move the field forward.