As a species group, sharks tend to be unproductive compared to other fishes. As a result, fishing effort must be maintained at a relatively low level if it is to be sustainable and if the shark populations are to be conserved. The Shark Research Laboratory and Fisheries and Oceans Canada (DFO) are firmly committed to shark conservation. To meet this goal, the Shark Research Lab seeks to describe, understand and monitor the population dynamics of all shark species in Atlantic Canada. As new scientific results are obtained, they are incorporated into shark management to help insure that all shark fisheries are being managed sustainably. This process is ongoing, and usually takes place independently of, and before, any recommendations from outside agencies. A point in case is the porbeagle shark, whose catch quota was cut by 75%, and the Newfoundland mating grounds closed to fishing, to allow population recovery before any recommendations from outside of DFO.
The existing management of shark populations in Canadian waters is designed to maintain shark population numbers at healthy levels. Several restrictions make this possible:
- All recreational fishing for sharks is restricted to catch and live release, with the exception of authorized shark derbies where DFO Science staff are present to collect scientific data on the sharks.
- All commercial shark fishing quotas are set at levels which maintain or increase population numbers at healthy levels, based on the best available scientific information.
- Sharks caught accidentally in fisheries targeting other species are to be released alive, if they are not landed.
- The mating ground of porbeagle sharks has been closed to commercial fishing to encourage population recovery.
There are several national and international organizations which serve to make recommendations on the conservation of shark populations. As a country, Canada subscribes to FAO's International Plan of Action on Sharks and Rays. Canada released its National Plan of Action for the Conservation and Management of Sharks in 2007, although it has been applying the same shark conservation principles for many years. The 2012 Progress Report on the National Plan of Action summarizes the current status of shark conservation efforts in Canada. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) reviews the population status of potentially endangered wildlife in Canada, then categorizes each population in terms of its relative abundance or health. These recommendations are then passed onto the Canadian government for possible action under the Species at Risk Act (SARA). If the population or species is listed under SARA, strict measures must be taken to aid in the conservation of the species. However, the government may elect not to list a species under SARA, even though it is listed under COSEWIC. In such a case, measures to protect the species and increase abundance are taken under existing, non-SARA measures.
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has reviewed the population health of several shark species to date. COSEWIC recommended that porbeagle sharks be designated as Endangered, based on the stock information summarized in Campana et al. (2003). To update and improve the available information on porbeagle, a comprehensive stock assessment was carried out in 2005 ( Gibson and Campana 2005), concluding that population numbers are low but have remained relatively stable since the reduction of catch quotas in 2002 ( Stock Assessment Report 2005). All analyses indicate that the population can recover, but that human-induced mortality needs to be kept below about 4% of vulnerable biomass (about 185 t per year) ( Recovery Assessment Report 2005). Since DFO is determined that the population recover, current and future management of this species will ensure that mortality is kept below the 4% level required for recovery. As such, the government has decided that porbeagle will not be listed as endangered under the Species At Risk Act (SARA). The most recent stock assessment indicates that population recovery has already begun ( Stock Assessment 2010) ( Stock Assessment 2012).
COSEWIC has also recommended that great white sharks be listed as Endangered, that shortfin makos be listed as Threatened, and that blue sharks be listed as Special Concern. Recovery Potential Assessments completed in 2006 are available for shortfin mako and white sharks. In 2011, the federal government listed the white shark as Endangered under SARA. COSEWIC has also looked at the status of spiny dogfish and basking shark, designating them as of Special Concern. Preliminary status reports for basking sharks and spiny dogfish are currently available.
The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international agency which attempts to protect endangered species through trade regulations, such as restrictions on import and export. A decision to list under Appendix II would place trade restrictions in place, unless it could be demonstrated that the population was being managed sustainably. CITES currently lists two shark species found in Canadian waters under Appendix II: great white sharks and basking sharks. In May 2007 and again in March 2010, two other species were proposed for listing under Appendix II - porbeagle and spiny dogfish - but the proposals were not accepted.
The 9th meeting of the Conference of the Parties of the United Nations Convention on the Conservation of Migratory Species of Wild Animals (CMS) listed porbeagle, mako (shortfin and longfin) and northern populations of spiny dogfish under Appendix II in Dec 2008. Appendix II "lists species suffering from unfavorable conservation status and would benefit from international cooperation". The listing was largely in response to heavy overfishing of the three species in European waters. Although a CMS listing is not legally binding, it often serves as the foundation from which legally binding treaties evolve.
The Shark Specialist Group of the International Union For Conservation of Nature (IUCN) provides information and guidance to governments and non-governmental organizations associated with the conservation of threatened shark species and populations. The SSG released their report on the Global Status of of Oceanic Pelagic Sharks and Rays in 2009. On-line access to the IUCN Red List is now available.
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