Clarke Shelley C, Magnussen Jennifer E, Abercrombie Debra L, McAllister Murdoch K, Shivji Mahmood S
Joint Institute for Marine and Atmospheric Research, c/o National Research Institute of Far Seas Fisheries, 5-7-1 Orido-Shimizu, Shizuoka 474-0022, Japan.
Conserv Biol. 2006 Feb;20(1):201-11. doi: 10.1111/j.1523-1739.2005.00247.x.
The burgeoning and largely unregulated trade in shark fins represents one of the most serious threats to shark populations worldwide. In Hong Kong, the world's largest shark fin market, fins are classified by traders into Chinese-name categories on the basis of market value, but the relationship between market category and shark species is unclear preventing identification of species that are the most heavily traded. To delineate these relationships, we designed a sampling strategy for collecting statistically sufficient numbers of fins from traders and categories under conditions of limited market access because of heightened trader sensitivities. Based on information from traders and morphological inspection, we hypothesized matches between market names and shark taxa for fins within 11 common trade categories. These hypotheses were tested using DNA-based species identification techniques to determine the concordance between market category and species. Only 14 species made up approximately 40% of the auctioned fin weight. The proportion of samples confirming the hypothesized match, or concordance, varied from 0.64 to 1 across the market categories. We incorporated the concordance information and available market auction records for these categories into stochastic models to estimate the contribution of each taxon by weight to the fin trade. Auctioned fin weight was dominated by the blue shark (Prionace glauca), which was 17% of the overall market. Other taxa, including the shortfin mako (Isurus oxyrinchus), silky (Carcharhinus falciformis), sandbar (C. obscurus), bull (C. leucas), hammerhead (Sphyrna spp.), and thresher (Alopias spp.), were at least 2-6% of the trade. Our approach to marketplace monitoring of wildlife products isparticularly applicable to situations in which quantitative data at the source of resource extraction are sparse and large-scale genetic testing is limited by budgetary or other market access constraints.
蓬勃发展且基本不受监管的鱼翅贸易是全球鲨鱼种群面临的最严重威胁之一。在全球最大的鱼翅市场香港，交易商根据市场价值将鱼翅按中文名分类，但市场类别与鲨鱼种类之间的关系尚不清楚，这使得难以确定交易最频繁的鲨鱼种类。为了厘清这些关系，由于交易商敏感度提高，市场准入受限，我们设计了一种采样策略，以便在这种情况下从交易商和类别中收集数量具有统计学意义的鱼翅样本。根据交易商提供的信息和形态学检查，我们对11个常见贸易类别中的鱼翅市场名称与鲨鱼分类单元之间的匹配关系进行了假设。利用基于DNA的物种鉴定技术对这些假设进行了检验，以确定市场类别与物种之间的一致性。只有14种鲨鱼约占拍卖鱼翅重量的40%。在各个市场类别中，确认假设匹配或一致性的样本比例从0.64到1不等。我们将这些类别的一致性信息和可用的市场拍卖记录纳入随机模型，以估计每个分类单元按重量对鱼翅贸易的贡献。拍卖的鱼翅重量中，大青鲨（Prionace glauca）占主导，占整个市场的17%。其他分类单元，包括灰鲭鲨（Isurus oxyrinchus）、丝鲨（Carcharhinus falciformis）、沙虎鲨（C. obscurus）、公牛鲨（C. leucas）、双髻鲨（Sphyrna spp.）和长尾鲨（Alopias spp.），至少占贸易量的2%至6%。我们对野生动物产品市场监测的方法特别适用于资源开采源头的定量数据稀少且大规模基因检测受到预算或其他市场准入限制的情况。
