On the relationship between squid and the environment: artisanal jigging for Loligo plei at São Sebastião Island (24°S), southeastern Brazil

Abstract

Postuma, F. A., and Gasalla, M. A. 2010. On the relationship between squid and the environment: artisanal jigging for Loligo plei at São Sebastião Island (24°S), southeastern Brazil. – ICES Journal of Marine Science, 67: 1353–1362. The squid Loligo plei concentrates in the southeastern Brazil Bight, where it has traditionally supported small-scale fisheries around São Sebastião Island (SSI). Sea surface temperature (SST), chlorophyll-a (Chl a), windspeed, wave height, rainfall, and lunar phase are related to fishing records and to the results of a survey of local fishers to investigate how they believe environmental variables might affect catches of L. plei. Daily fishery-dependent data over the years 2005–2009 were obtained from a fishing cooperative and were matched with satellite and meteorological forecast data. Generalized linear models were used to explore the significance of environmental variables in relation to variability in catch and catch per unit effort (cpue). Squid are fished with jigs in water shallower than 20 m, generally where SST is warmer and Chl a and windspeed are lower. Cpue and monthly catches decreased from 2005 to 2008, followed by a slight increase in 2009. The correlations between fishery and environmental data relate well to fishers' oceanological knowledge, underscoring the potential of incorporating such knowledge into evaluations of the fishery.

A method for assessing fishers’ ecological knowledge as a practical tool for ecosystem-based fisheries management: Seeking consensus in Southeastern Brazil

“…The first two are species with the major landing biomasses, in kilograms, in Ubatuba, and represent fish resources of greatest commercial value in the municipality (Instituto de Pesca, 2008). The squid and the white shrimp were chosen because of their importance (in catch and income) for local communities, the squid during summer, especially from November to April (Rodrigues and Gasalla, 2008;Postuma and Gasalla, 2010), and the white shrimp during winter, especially from June to September . Finally, the blue runner Caranx crysos was also selected because of its commercial importance and the lack of local data and knowledge regarding its ecology in the study area (and in Brazil, in general).…”

“…In this sense, a consistent compatibility was found between the data transmitted by key fishers and some previous scientific studies in other regions for the: (1) white-mouth croaker Micropogonias furnieri (Menezes and Figueiredo, 1980;Robert and Chaves, 2001;Costa and Araújo, 2003;Bernardes et al, 2005;Carneiro et al, 2005;Carneiro, 2007;Vazzoler, 1971;Vazzoler et al, 1989); (2) seabob-shrimp Xiphopenaeus kroyeri (Nakagaki and Negreiros-Fransozo, 1998;Fransozo et al, 2000;Castro et al, 2005;Freire, 2005); (3) inshore squid Loligo spp. (Perez et al, 2002(Perez et al, , 2005Martins and Perez, 2006;Rodrigues and Gasalla, 2008;Gasalla et al, 2010;Postuma and Gasalla, 2010); (4) white shrimp Litopenaeus schimitti (Chagas-Soares et al, 1995;Costa, 2002;Castilho et al, 2007;Costa et al, 2007;Gonç alves et al, 2009) and (5) blue runner Caranx crysos (Leak, 1981). However, these studies were conducted in other areas of the Brazilian coast, and there is no information for our study site.…”

Reproductive activity of the tropical arrow squid Doryteuthis plei around São Sebastião Island (SE Brazil) based on a 10-year fisheries monitoring

“…This may be due to the effect of fishing gear selectivity, as suggested by Martins and Perez (2007) that compared values obtained from squid caught by hand-jigging and fish-traps in Santa Catarina Island. Postuma and Gasalla (2010) showed that the hand-jigging of D. plei squid targets dense concentrations of squid in austral-summer months (November-April), with CPUE peaks between February and March, where sea surface temperature were warmer. Present study confirms that these squid were in reproductive activity, as indicated by the positive correlation between gonad weight and month, for both sexes.…”

“…it breeds only once in a lifetime (Boyle and Rodhouse, 2005). The species comprises an important fishery resource off the southern and southeastern coast of Brazil (Perez et al, , 2005Gasalla et al, 2005;Rodrigues and Gasalla, 2008;Postuma and Gasalla, 2010;Gasalla et al, 2010). Its distribution ranges from the coast of Florida, USA (Hixon et al, 1980) to Rio Grande do Sul, Brazil (Perez et al, 2005), and in the southernmost portion its presence has been associated with the Brazil Current (Haimovici and Perez, 1991) and with South Atlantic Central Waters (SACW) summer bottom intrusions (Martins et al, 2006).…”

“…D. plei appears to spawn throughout the year, more intensely in summer, when the fisheries seem to take advantage of the spawning concentrations Rodrigues and Gasalla, 2008). In this regard, both artisanal (hand-jigging) and industrial (shrimp-trawling) fisheries have exploited the stock in the whole area (Perez, 2002;Gasalla et al, 2005;Postuma and Gasalla, 2010). Some differences on spatial patterns in size-at-maturity in respect to season, depth ranges, and inshore-offshore migration have been found along the region, converging that summer coastal spawning squid tend to mature at larger sizes than their offshore counterparts in winter Rodrigues and Gasalla, 2008).…”