Use of total allowable catch to regulate a selective marine aquarium fishery by Thane A. Militz, Jeff Kinch, David S. Schoeman, Paul C. Southgate
Abstract
The Papua New Guinea (PNG) marine aquarium fishery was partly managed by total allowable catch (TAC) limits, implemented since the fishery's inception in 2008. Species-specific TACs, based on stock assessments conducted prior to the commencement of fishing, were established for all fish and invertebrate species presumed to be fished by the fishery. By analysing the selectivity of the PNG fishery in 2012, a large portion (74.9%) of the managed fish diversity (n = 267 species) was found to be “weakly” to “strongly” avoided relative to their availability. More than half (53.2%; n = 142) of the fish species with TACs were never fished in 2012. Of those species with TACs that were actually fished, 76.8% (n = 96) of fish and all invertebrate catches never exceeded 1% of their TACs. Catches of only seven fish species exceeded 10% of their TACs. Catch records also identified 124 fish species that were fished in the absence of species-specific TACs. Unbiased recursive partitioning was used to examine ecological attributes of these species to help identify flaws in the methods used for initial TAC assignment. Refining the role species-specific TACs play in the management of this fishery is necessary to op- timise managerial resources. The lessons learned from this approach to marine aquarium fishery management are likely to be of interest and value to PNG, other developing island nations, and marine aquarium fisheries globally. Request full-text
Aquarium Trade Supply - Chain Losses of Marine Invertebrates Originating from Papua New Guinea by Thane A. Militz, Jeff Kinch,Paul C. Southgate
Abstract
A major difficulty in managing live organism wildlife trade is often the reliance on trade data to monitor exploitation of wild populations. Harvested organisms that die or are discarded before a point of sale are regularly not reported. For the global marine aquarium trade, identifying supply-chain losses is necessary to more accurately assess exploitation from trade data. We examined quality control rejections and mortality of marine invertebrates (Asteroidea, Gastropoda, Malacostraca, Ophiuroidea) moving through the Papua New Guinea marine aquarium supply-chain, from fisher to importer. Utilizing catch invoices and exporter mortality records we determined that, over a 160 day period, 38.6% of the total invertebrate catch (n = 13,299 individuals) was lost before export. Supply-chain losses were divided among invertebrates rejected in the quality control process (11.5%) and mortality of the accepted catch in transit to, and during holding at, an export facility (30.6%). A further 0.3% died during international transit to importers. We quantified supply-chain losses for the ten most fished species which accounted for 96.4% of the catch. Quality control rejections (n = 1533) were primarily explained by rejections of oversized invertebrates (83.2% of rejections). We suggest that enforceable size limits on species prone to size-based rejections and elimination of village-based holding of invertebrates would reduce losses along the Papua New Guinea supply-chain. This case study underscores that low mortality during international transit may mask large losses along supply- chains prior to export and exemplifies the limitations of trade data to accurately monitor exploitation. Request full-text
Gordon Miller