Spatial and temporal patterns in size and maturation of Loligo plei and Loligo sanpaulensis (Cephalopoda: Loliginidae) in southeastern Brazilian waters, between 23 degrees S and 27 degrees S

Patterns of population dynamics of Loligo plei and Loligo sanpaidensis in Southeastern Brazil were investigated with samples obtained from commercial catches and research cruises from 1999 to 2000 and from 2002 to 2003. Size and maturity Structure of the two species varied according to depth and season. Body size decreased with depth for L plei, whereas for L. sanpaidensis size increased with depth LIP to 100 m and decreased again in deeper areas. GSI and incidence of mature animals decreased with depth in both species. L. plei females matured at a larger size in summer, while size at maturity in L. sanpaulensis was greater in autumn. For L. plei, reproductive events Occurred in the late winter and spring, in depths up to 40 m, and during summer in inshore waters. L. sanpaidensis increased reproductive activity ill Summer, winter and spring between depths of 30 and 80 Ill. The presence of high proportions of immature Squid offshore Suggests that juveniles might develop in these areas and, upon maturation, migrate back to inshore waters to spawn, particularly in spring and Summer. However, differences found in aggregation patterns in different depth strata, as well as the seasonal differences found in the size structure of L. plei and L. sanpaidensis, Could ultimately be due to Changes in the water Column related to food availability. Considering that L. plei and L. sanpaidensis are both caught as by-catch by shrimp trawlers throughout file year, we also discuss hypotheses on the life cycle of the species and its implications for fishery management. We recommend measures to protect squid spawning grounds by creating spring and summer protected areas where trawling would be prohibited until 60 m depth, i.e. in the area and time of year when mature individuals concentrate.

A resource management scenario for traditional and scientific management of pink shrimp (Farfantepenaeus paulensis) in the Patos Lagoon estuary (RS), Brazil

Abstract Background This article aims to discuss the incorporation of traditional time in the construction of a management scenario for pink shrimp in the Patos Lagoon estuary (RS), Brazil. To meet this objective, two procedures have been adopted; one at a conceptual level and another at a methodological level. At the conceptual level, the concept of traditional time as a form of traditional ecological knowledge (TEK) was adopted. Method At the methodological level, we conduct a wide literature review of the scientific knowledge (SK) that guides recommendations for pink shrimp management by restricting the fishing season in the Patos Lagoon estuary; in addition, we review the ethno-scientific literature which describes traditional calendars as a management base for artisanal fishers in the Patos Lagoon estuary. Results Results demonstrate that TEK and SK describe similar estuarine biological processes, but are incommensurable at a resource management level. On the other hand, the construction of a “management scenario” for pink shrimp is possible through the development of “criteria for hierarchies of validity” which arise from a productive dialog between SK and TEK. Conclusions The commensurable and the incommensurable levels reveal different basis of time-space perceptions between traditional ecological knowledge and scientific knowledge. Despite incommensurability at the management level, it is possible to establish guidelines for the construction of “management scenarios” and to support a co-management process.