Distribution of the New Zealand scallop (Pecten novaezealandiae) within and surrounding a customary fisheries area

Abstract

Ecosystem-based approaches towards fisheries management, incorporating spatial management, have recently been advocated as the most appropriatepathway towards sustainable fisheries. Customary fisheries management, which often incorporates forms of spatial management, could be an important tool for engaging ecosystem fisheries approaches in practice. This study measured habitat characteristics and the density of the scallop Pecten novaezealandiae across a range of management regimes in Te Whaka a¯ Te Wera (Paterson Inlet), Rakiura (Stewart Island), New Zealand. These regimes included (i) a customary fisheries area (Te Whaka a¯ Te Wera Ma¯taitai) managed locally under a traditional closure to scallop harvest (ra¯hui), (ii) a complete closure to all harvest and anthropogenic disturbances (Te Wharawhara/Ulva Island Marine Reserve), and (iii) an area open to recreational harvest of scallops by hand gathering over a limited season. Habitat characteristics and scallop numbers were measured using strip-transect and photoquadrat surveys at 20 sites within Te Whaka a¯ Te Wera in June 2013. Negative binomial regression modellingwas used to relate the counts of scallops to management regime and habitat characteristics. Scallops were likely to be at a higher density in the customary fisheries management area than in the marine reserve and the recreational harvest area. Pecten novaezealandiaewere likely to be at a higher density with increasing distance from the inlet entrance, which is likely to be a proxy for a gradient of habitat or environment variables. Scallops were also likely to be at lower densities in areas of high macroalgal cover, perhaps reflective of adult scallops avoiding areas with significant algal cover. Our study showed that customary fisheries areas can provide effective refugia for scallops, provided they protect appropriate habitat.