Short CommunicationAssessment of current data for the octopus resource in Rodrigues, western Indian Ocean

The annual catch of octopus in the Rodrigues Lagoon, located east/north-east of Mauritius, has dropped by almost half since 1994. This has prompted concern over the resource and has initiated an assessment of the current status of the stock. The limited available biological information suggests that the main pulse of recruitment into the lagoon occurs in the first few months of the year, but that exact timing varies between years and additional staggered recruitment may occur throughout the year. Size frequency information suggests that the brooding period may be variable and extended, with a main peak between October and January. Catch-and-effort data were also limited, but a decreasing trend in catch per unit effort in two of the datasets examined allowed some preliminary withinseason assessment of population size (using a depletion model) at selected landing sites. The use of a migration bias correction formula suggested a net emigration from the lagoon, which might be indicative of adult movement into deeper waters. Depletion models seem to be useful as a management tool and should be tested further against more substantial monthly catch-and-effort data. In the interim, a precautionary approach of instituting a national seasonal closure for octopus fishing following periods of peak recruitment may have both economic and conservation benefits.Keywords: growth, management recruitment, Octopus cyanea, regulations, reproduction, stock assessmentAfrican Journal of Marine Science 2011, 33(1): 181–18

Lessons learnt from experimental temporary octopus fishing closures in south-west Madagascar: benefits of concurrent closures

This paper presents evidence of the fisheries effect of experimental temporary fishing closures for Octopus in the then-emergent Velondriake Locally Managed Marine Area (LMMA) in south-west Madagascar during 2004–2006. We present an analysis of the O. cyanea catch data for the first two years of temporary closures based on landings data collected from village-based octopus collectors. We found a significant closure effect in terms of total weight and number of octopus caught on opening days, but observed that these benefits dissipated quickly, returning to pre-closure levels within days. Mean octopus size increased by 41% on average when compared to data from selected control sites. However, extremely high levels of fishing effort on opening days meant that these biological effects did not translate into increased weight of octopus caught per successful fisher over the opening tide. Upon opening of concurrent closures during the second round of closures we found significant increases in the weight of octopus caught per successful fisher. We conclude that the pilot closures had a significant closure effect, but caution against isolated openings leading to concentrated fishing effort on opening days.Keywords: fishery management, locally managed marine area (LMMA),  Octopus cyaneaAfrican Journal of Marine Science 2014, 36(1): 31–3

Lessons learnt from experimental temporary octopus fishing closures in south-west Madagascar: benefits of concurrent closures

This paper presents evidence of the fisheries effect of experimental temporary fishing closures for Octopus in the then-emergent Velondriake Locally Managed Marine Area (LMMA) in south-west Madagascar during 2004–2006. We present an analysis of the O. cyanea catch data for the first two years of temporary closures based on landings data collected from village-based octopus collectors. We found a significant closure effect in terms of total weight and number of octopus caught on opening days, but observed that these benefits dissipated quickly, returning to pre-closure levels within days. Mean octopus size increased by 41% on average when compared to data from selected control sites. However, extremely high levels of fishing effort on opening days meant that these biological effects did not translate into increased weight of octopus caught per successful fisher over the opening tide. Upon opening of concurrent closures during the second round of closures we found significant increases in the weight of octopus caught per successful fisher. We conclude that the pilot closures had a significant closure effect, but caution against isolated openings leading to concentrated fishing effort on opening days.Keywords: fishery management, locally managed marine area (LMMA),  Octopus cyaneaAfrican Journal of Marine Science 2014, 36(1): 31–3