EVALUATING TRADE-OFFS IN AN ECOSYSTEM-BASED FISHERY MANAGEMENT PARADIGM: AN EXPLORATION THROUGH ANALYSIS OF THE ATLANTIC BUTTERFISH AND LONGFIN SQUID FISHERIES

Abstract

The Mid-Atlantic Fishery Management Council, our client for this masters project, is evaluating how best to transition from a primarily single-species management approach to an integrated multi-species management paradigm. In this connection, we explore how economic considerations may be incorporated into an integrated multi-species management approach by focusing on two closely associated stocks managed by the Council: longfin squid and Atlantic butterfish. We take several different approaches in our analysis of the two fisheries, our ultimate objectives being (i) to characterize the behavior of the fleets based upon historical landings data and geospatial analysis; and (ii) to provide the Council with insight into the potential impact of management constraints and ecosystem interactions on economic benefits in the fisheries. To illustrate potential impacts to economic benefits, we develop a two-species bioeconomic model and derive optimal harvest levels for the stocks, taking into account varying degrees of management constraints and ecosystem interactions. Based upon our analysis of landings data, we found that the Council’s allocation of the longfin squid landings quota among trimester management periods is no longer representative of actual landings in the fishery throughout the year. As a result, there is potential that the fishery may be forced to close prematurely in the summer months, thereby reducing economic benefits to participants who are highly dependent on revenues from the fishery. We also found, based upon our geospatial analysis of butterfish landings and butterfish bycatch in the longfin squid fishery, that a statistically significant correlation exists between the distance to shore from the point of catch and the butterfish bycatch rate. With respect to the model, we explored the importance of three parameters not generally included in a single-species model: predation, bycatch by fishermen, and benefits to the longfin squid population of additional butterfish. We found that all three have potential economic impacts. We also found that the amount of the total allowable catch of butterfish allocated to a bycatch cap imposed on the longfin squid fishery is higher than necessary to prevent early closure of the longfin squid fishery and could result in lost revenues in the butterfish fishery.