4. Assessment of Proposals

4.3 - Proposal 11.49. Basking shark (Cetorhinus maximus)
         (see Annex 3)

Currently not on the Appendices. Add to Appendix II pursuant to criteria A and Bi of Annex 2 (Resolution Conf. 9.24) (United Kingdom).

Status: IUCN lists the global population of C. maximus as Vulnerable (criterion A1: a population reduction of at least 20% in three generations has been observed, estimated, inferred or suspected, based on (a) an index of abundance, (d) actual or potential levels of exploitation; criterion A2: the population reduction specified in A1 is suspected to continue to be met over the next three generations).

Trade: C. maximus are currently in international trade; liver oil and fins being the two main trade products. Basking shark fins are one of the most valuable sold in Singapore (Walker 1998). The only directed fishery (operated by Norway) uses much of its catch for national consumption, extracting squalene from the liver oil for cosmetics and health supplements (C. maximus proposal).

Population size and declines: Commercial fisheries are reported to have resulted in significant long-term localised declines in many areas. Past declines indicate localised stock reductions of 50–90% over short periods, followed by a lack of apparent recovery several decades after exploitation ceased (C. maximus proposal). In terms of meeting the criteria:

Annex 2a, Criteria A: It is known, inferred or projected that unless trade in the species is subject to strict regulation, it will meet at least one of the criteria of Annex 1 in the near future.

There is no evidence indicating that the species will meet the Criteria for Appendix I in the near future – the global population size is large, and projected declines are unlikely to be of sufficient magnitude.

Annex 2, Criteria B: It is known, inferred or projected that the harvesting of specimens from the wild for international trade has, or may have, a detrimental impact on the species by: i) exceeding, over an extended period, the level that can be continued in perpetuity.

In most cases of local population decline, there is insufficient information on trends in CPUE to determine the extent of reduction, and the degree to which they are related to exploitation. This is further complicated by poorly known migratory movements, a lack of understanding of stock size and structure, and an inability to account for what are apparently significant natural fluctuations in local abundance regardless of exploitation. For example, exceptionally high numbers of C. maximus were recorded France and south-west England in 1998, but not in other areas of the UK. They have been reported as both "rare" and "abundant" off California in different years. Aerial surveys off California have found them to be more abundant before 1970 than recently, despite no significant fishing having taken place since 1950 (FAO fact sheet).

Conclusion: Cetorhinus maximus may meet the criteria for Appendix II Bi on a local level (European waters for the Norwegian fleet), but the global population is not significantly threatened. The current EC quota (~200 sharks PA) may be sufficient for ensuring current exploitation is not excessive and monitoring associated with this harvest could be important for quantifying the status of this local population in the future. The proposal does not justify listing of the global population on Appendix II.