Aquarium Trade Supply-Chain Losses of Marine Invertebrates Originating from Papua New Guinea

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.