Author(s): Shang-Yin Vanson Liu 1,2, Chia-Ling Carynn Chan 1, Oceana Lin 3, Chieh-Shen Hu 3, Chaolun Allen Chen 1,4,5,*
Unsustainable fishing pressure has led to the decline of most shark populations, and some are facing extinction , , . These predators play a crucial ecological role in structuring marine ecosystems and food webs , and are commercially important for their meat and particularly their fins. Late maturation, low fecundity, and longevity make sharks acutely vulnerable to overexploitation and prevent rapid recovery from over-fishing .
Recent global catch assessments estimated approximately 100 million sharks are landed annually, excluding illegal, unreported, and unregulated shark catches . Evidence of continuing over-fishing of shark populations triggered immediate conservation actions by the Food and Agriculture Organization of the United Nations (FAO), international treaties such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and the creation of regional fisheries management organizations (RFMOs) by shark harvesting countries and entities. A review of global actions and inaction on sharks  reported the global shark fishery is primarily driven by 20 countries, with Indonesia (13%), India (9%), Spain (7.3%), Taiwan (5.8%), and Argentina (4.3%) contributing most to shark landings. Thirteen shark harvesting countries are known to have national plans of action for conserving and managing sharks (NPOA-Sharks). However, no substantial evidence exists to indicate that NPOAs are increasing the effective management of shark fisheries in their countries .
Taiwan's fleet has the 4th largest shark catch in the world, with a declared 6 million sharks caught annually, accounting for almost 6% of the global figures. However, these numbers could be greatly underestimated. Biogeographically, Taiwan has the highest species diversity of sharks in the world . Between 1996 and 2006, annual Taiwanese shark landings (coastal, offshore, and pelagic combined) averaged between 39,000 and 55,000 metric tons. Sharks are captured primarily by bottom longline, mid-water longline, large-mesh drift-net, and as by-catch of the tuna longline fishery. The dominant species are Prionace glauca (blue shark), Isurus oxyrinchus (shortfin mako shark), Sphyrna lewini (scalloped hammerhead shark), S. zygaena (smooth hammerhead shark), Alopias superciliosus (bigeye thresher shark), A. pelagicus (pelagic thresher shark), Carcharhinus plumbeus (sandbar shark), C. falciformi s (silky shark), C. longimanus (oceanic whitetip shark), C. brevipinna (spinner shark), and C. obscurus (dusky shark) .
The Taiwanese government initiated NPOA-Sharks on 05 May 2006 , and Taiwan became the first Asian nation to implement a ban on shark finning in early 2012. The new law requires that sharks be landed naturally with their fins attached, where fishes are to be inspected and identified, and then processed at port. Fleets that violate the regulations are heavily fined and may have their fishing licenses revoked.
Stock assessments have been severely hampered by the lack of species-specific catch data in most fisheries, especially sharks . The shark fisheries data released by the Fisheries Agency, Council of Agriculture, Taiwan (FA-COA) contain no species-specific catch data, which is mainly due to unintegrated catch data from landings, commercial fishing vessels, and...