LOLIGINID SQUID FISHERY AROUND ARVOREDO ISLAND (SANTA CATARINA, BRASIL): CHARACTERISTICS AND ECOLOGICAL RELATIONSHIPS, SUMMER 1996.

Abstract

During the austral summer, important concentrations of the long-finned squid, Loligo piei, occur on the continental shelf off Santa Catarina State, southern Brazil. These populations have sustained offshore annual catches ranging from 144 to 763 metric tonnes, and have originated an inshore artisan fishery around the coastal islands. This report describes this fishery around the Arvoredo Island (48°22'W; 27°17'S) and analizes: (a) the dynamics of catches in relation to environmental fluctuations and (b) the population structure of catched squid. Information on boat features, fishing techniques, fishing areas, catch and effort were obtained between January and March 1996, from interviews with fishermen during landings at the locality of Governador Celso Ramos. Squid samples were obtained from commercial catches and from five sampling trips conducted in the main fishing area off Arvoredo Island during the same period. During each trip surface and subsurface currents speed and direction as well as the thermal structure of the water column were continuously monitored. The inshore fishery is conducted by 9 to 11 m long boats known as "botes" or "bateiras", powered by 9 to 24 HP engines. Squid is captured by hand lines and a type of jig called "zangarilhos" which are operated by 2 to 4 men on each boat. Fishing takes place mainly on 10 to 20 m deep grounds located in the southeastern shore of the island in an area known as "Saco do Capim", where boats anchor for 33h (±12,4 SD) on average per trip. Catches occur either during the day (bottom fishing) or at night when the boat lights are used to attract squids to the surface. Mean catch and mean catch per unit of effort were 49,6 Kg per trip (±56,4 SD, n =35) and 0,56 Kg.maril .hour-1 (±Q,71 SD) respectively. Commercial catches showed marked temporal peaks as a response to fluctuations on the squid occurrence in the area. Squid were catched: (a) in either homogenized or stratified water column; (b) at temperatures ranging from 18 to 26° C; and (c ) when subsurface water layers were flowing SW off the island shore. Most males and females caught were in advanced sexual maturity stages.