U.S. Fisheries Management and Foreign Trade Linkages: Policy Implications for Groundfish Fisheries in the North Pacific EEZ

The groundfish resources of the U.S. Exclusive Economic Zone (EEZ) off Alaska, dominated by Alaska or walleye pollock, Theragra chalcogramma, Pacific cod, Gadus macrocephalus, and flatfishes, Pleuronectidae, can sustain annual commercial harvests well in excess of 2 million metric tons (t). As recently as 1979, foreign fisheries took 99 percent of the annual harvest supported by these resources. This has changed dramatically during the 1980's. The foreign fisheries have received rapidly decreasing allocations, first as joint venture fisheries expanded and, more recently, as the domestic fisheries have grown. Joint venture fisheries are fisheries in which domestic fishing vessels deliver their catch directly to foreign processing vessels in the EEZ. By 1986, the joint venture and domestic fisheries accounted for 66 percent and 8 percent, respectively, of the annual harvest. The preliminary corresponding figures for 1987 are 78 and 18 percent.

A model for assessing the likelihood of self-sustaining populations resulting from commercial production of triploid Suminoe oysters (Crassostrea ariakensis) in Chesapeake Bay

Culture of a non-native species, such as the Suminoe oyster (Crassostrea ariakensis), could offset the harvest of the declining native eastern oyster (Crassostrea virginica) fishery in Chesapeake Bay. Because of possible ecological impacts from introducing a fertile non-native species, introduction of sterile triploid oysters has been proposed. However, recent data show that a small percentage of triploid individuals progressively revert toward diploidy, introducing the possibility that Suminoe oysters might establish self-sustaining populations. To assess the risk of Suminoe oyster populations becoming established in Chesapeake Bay, a demographic population model was developed. Parameters modeled were salinity, stocking density, reversion rate, reproductive potential, natural and harvest-induced mortality, growth rates, and effects of various management strategies, including harvest strategies. The probability of a Suminoe oyster population becoming self-sustaining decreased in the model when oysters are grown at low salinity sites, certainty of harvest is high, mini-mum shell length-at-harvest is small, and stocking density is low. From the results of the model, we suggest adopting the proposed management strategies shown by the model to decrease the probability of a Suminoe oyster population becoming self-sustaining. Policy makers and fishery managers can use the model to predict potential outcomes of policy decisions, supporting the ability to make science-based policy decisions about the proposed introduction of triploid Suminoe oysters into the Chesapeake Bay.