Scale, dynamic and management in the Harvesting of Mussel in North Patagonia (Argentina)

Abstract

Mussels were fished in San Matías Gulf (Argentine Patagonia) during three decades using dredges and performing a small-scale fishery. This fishery was characterized by pulses of productivity (1988-1992; 2002-2008) determined by the spasmodic nature of recruitment. Annual landings ranged among 200 – 2100 t. During the first pulse, the exploitation was done mainly by the industrial fleet, with vessels that operated on several fishing grounds, switching among them in response to abundance. The state of fishing grounds was assessed based in surveys conducted between 1987 and 1997, following the same methodology (vessel, dredge and sampling design) to estimate abundance of mussels and other epifaunal components using catch and swept-area data. A research program conducted during this period was addressed to collect data about population dynamics and harvesting. After nine years without successful recruitments, in early 2001 new settlements was detected and the fishery was re-opened to exploitation. In this second pulse the reduction of the fishery scale (only artisanal fishing was allowed) was established by Administration. More than 30 artisanal boats (less than 10 m length) operated with two modalities: diving and small-sized dredges. The purpose of this chapter is: (1) to review, integrate and process the information of biological parameters, stock assessment and fishery, collected during both industrial and fishing pulses, (2) to analyze management constrains of both types of fisheries, including social and economics implications and, (3) to propose a management scheme with operative short term actions and strategic long term component to mitigate the effects of biological uncertainty (recruitment, spatial- temporal variability of abundance) and control difficulties.