Determination of stock structure in two marine fisheries using nuclear microsatellites.

摘要

Major fisheries around the world are in a state of decline due to overfishing. The formulation of effective management policies requires a certain level of knowledge about the biology of the target species, especially stock structure. Stocks can be defined in many ways. One of the most effective definitions is equivalent to a biological population. While such structure is detectable by direct observation of behavior or morphology in some species, in others it is more difficult. Molecular genetic markers are some of the most promising tools for stock identification and analyses of stock structure.; In this thesis I present work on developing and using one such type of genetic marker in two important marine fisheries. In the first, walleye pollock (Theragra chalcogramma), declines in catch are recent, and not yet catastrophic. In the other, red abalone (Haliotis rufescens), populations within the region where they are exploited have crashed, and the commercial fishery is presently closed. In both of these fisheries, attempts have been made to develop molecular genetic markers for the purpose of stock identification, without adequate success.; The markers I have developed are of a class known as microsatellites. In other species, microsatellites have been shown to be more variable, and therefore more able to detect differences, than other types of genetic markers. In pollock, these markers were both variable, and effective in identifying previously unknown stock structure. The markers found in abalone were also variable. As yet no statistically significant differences have been detected between geographic regions, though further investigation may eventually show that they do exist.