May 30, 2013 — The following was released by NOAA:
This status review report was conducted in response to a petition to list the scalloped hammerhead shark under the Endangered Species Act (ESA) (WildEarth Guardians and Friend of Animals to U.S. Secretary of Commerce, Acting through the National Oceanic and Atmospheric Administration and the National Marine Fisheries Service (NMFS), August 14, 2011, “Petition to list the scalloped hammerhead shark (Sphyrna lewini) under the U.S. Endangered Species Act either worldwide or as one or more distinct population segments”). NMFS evaluated the petition to determine whether the petitioner provided substantial information as required by the ESA to list a species. Additionally, NMFS evaluated whether information contained in the petition might support the identification of a distinct population segment (DPS) that may warrant listing as a species under the ESA. NMFS determined that the August 14, 2011 petition did present substantial scientific and commercial information, or cited such information in other sources, that the petitioned action may be warranted and, subsequently, NMFS initiated a status review of the scalloped hammerhead shark. This status review report is comprised of two components: (1) the “Status Review” of the species, a document that compiles the best available information on the status of the scalloped hammerhead shark as required by the ESA, and (2) the “Assessment of Extinction Risk” for the species, a document that provides the methods and conclusions of the NMFS Extinction Risk Analysis (ERA) team on the current and future extinction risks of the scalloped hammerhead shark.
The scalloped hammerhead shark (Sphyrna lewini) is a circumglobal species occurring in coastal warm temperate and tropical seas (Compagno 1984). Scalloped hammerhead sharks are highly mobile and partly migratory and are likely the most abundant of the hammerhead species (Maguire et al. 2006); however the risk of local depletions is of concern. Scalloped hammerhead sharks have a life history that is susceptible to overharvesting, and according to the most recent stock assessment (Hayes et al. 2009) the Northwestern Atlantic and Gulf of Mexico stock has declined to a relatively low level of abundance in recent years. Populations in other parts of the world are assumed to have suffered similar declines, however data to conduct stock assessments are currently lacking.
Based on a review of the best available information, the ERA determined that there exists six DPSs of the scalloped hammerhead shark, as defined by the joint U.S. Fish and Wildlife Service-NMFS interagency policy of 1996 on vertebrate distinct population segments under the ESA. Based on information related to genetic variation among populations, behavior and physical factors, and differences in international regulatory mechanisms, the ERA team identified a Northwest Atlantic & Gulf of Mexico DPS, Central & Southwest Atlantic DPS, Eastern Atlantic DPS, Indo-West Pacific DPS, Central Pacific DPS, and Eastern Pacific DPS of scalloped hammerhead sharks.
The ERA team ranked demographic risks and threats to each of the DPSs. In the case of the Northwest Atlantic & Gulf of Mexico DPS, the ERA team ranked the high at-vessel fishing mortality of scalloped hammerhead sharks as the most serious threat, with overutilization by industrial/commercial and recreational fisheries as moderate risks to the persistence of the DPS. For the Central & Southwest Atlantic DPS as well as the Eastern Atlantic DPS, overutilization by industrial/commercial fisheries and the high at-vessel fishing mortality of S. lewini were ranked as high risks, and overutilization by artisanal fisheries, lack of adequate regulatory mechanisms, IUU fishing, and the schooling behavior of the species were ranked as moderate risks to the persistence of these DPSs. In the Indo-West Pacific DPS, overutilization by industrial/commercial and artisanal fisheries, as well as IUU fishing and the high at-vessel mortality of the sharks were ranked as high risks, with habitat degradation, inadequacy of current regulatory mechanisms, and schooling behavior ranked as moderate risks. The main threat to the Central Pacific DPS was the high at-vessel fishing mortality of scalloped hammerhead sharks, with overutilization by industrial/commercial fisheries ranked as a moderate risk. Finally, for the Eastern Pacific DPS, the threats of overutilization by industrial/commercial and artisanal fisheries, as well as the impact of IUU fishing, high at-vessel fishing mortality and schooling behavior of the species were ranked as high risks, with the lack of current adequate regulatory mechanisms ranked as a moderate risk.
Based on an evaluation of abundance trends, growth and productivity, spatial structure, and diversity, as well as the threats listed above, the ERA team determined that the Central Pacific DPS was at a very low risk of extinction now and in the foreseeable future. The Northwest Atlantic & Gulf of Mexico DPS was at a low risk of extinction now and in the foreseeable future. The Central & Southwest Atlantic DPS and the Indo-West Pacific DPS were at a moderate risk of extinction now and in the foreseeable future, whereas the Eastern Atlantic DPS and Eastern Pacific DPS were at a high risk of extinction now and in the foreseeable future. The ERA team did not find any significant portion of range within a DPS that would warrant a different risk of extinction and therefore concluded that the extinction risk for each DPS applied to the entire range of that DPS.
Read the full report from NOAA