The Inter-American Tropical Tuna Commission (IATTC) will hold its 82nd annual meeting in La Jolla, California from July 4-8, 2011. The IATTC is one of five Regional Fisheries Management Organizations (RFMOs) established to manage fishing of tuna and tuna-like species. However, with the entry into force of the Antigua Convention in September 2010, the mandate of the IATTC has been updated to include an emphasis on implementing the ecosystem approach and precautionary principle in management decisions. This mandate offers the IATTC a critical opportunity to adequately address bycatch concerns and significantly reduce tuna fishing impacts on the ecosystem and on non-tuna species in the convention area such as sharks.

Reasons to support a prohibition on retention by IATTC fisheries

• Oceanic whitetip sharks are biologically vulnerable to overexploitation.
• They are targeted for their highly valued fins and also caught as bycatch.
• Oceanic whitetip sharks are the second most commonly caught species in purse seine fisheries in the eastern Pacific Ocean.¹
• While there is little information available on the population status of oceanic whitetip sharks, the data that is available has shown catch has steadily decreased, to the point of virtual disappearance.
• Declines in oceanic white tip catch per unit effort (CPUE) and biomass range from 30-90% in the Pacific.²
• Oceanic whitetip sharks have a high survival rate if released alive from longlines, but due to the high value of their fins, they are often not released.
• Round fins with distinguishable white marks make oceanic whitetip sharks easy to identify, which facilitates enforcement of measures.

Biological vulnerability to overexploitation

• Long gestation period of nine to 12 months.
• Low to moderate population growth rates, in comparison with other shark species.
• Long reproductive periodicity, reproducing every two years.
• Low reproductive capacity, with only five to six pups per litter.

Oceanic white tip fisheries and trade

The oceanic whitetip is one of the most widespread shark species and is found in all of the world’s oceans. While oceanic whitetip sharks were once one of the most commonly caught species, the high global demand for their large, high-value fins has led to significant population declines. Several targeted fisheries exist for oceanic whitetips, and they are frequently caught as bycatch in tuna and swordfish fisheries. Although this species experiences a high catch-survival rate on longline fishing equipment, the low market value of its meat coupled with the high value and increasing demand for its fins encourages the practice of finning.³ Fins of this species have been valued at US$45 to $85 per kilogram.⁴ Thus, rather than releasing live catch or utilizing the entire shark, fishermen often remove the fins at sea and dispose of the carcass overboard. Oceanic whitetip fins are easily
identifiable in trade by their white coloring, rounded shape and large size.

In the eastern Pacific Ocean, oceanic whitetip sharks are the second most commonly caught species in the purse seine fishery. In the IATTC Shark Characteristics Sampling Program in 2000-2001, oceanic whitetips accounted for more than 20 percent of the bycatch.⁵ Observers are capable of correctly identifying oceanic whitetip sharks, but data has shown they are often coded as “other sharks”, suggesting bycatch may actually be higher than what has been recorded.⁶ Catch data shows the bycatch of oceanic whitetip sharks is decreasing in all three purse seine set types, but the floating-object sets have the greatest potential for impacting the sustainability of these sharks.⁷ Comparisons of catch per set for oceanic whitetips from 1993-2008 suggests these sharks are no longer being caught.⁸ This scientific data should be cause for serious concern for the future survival of this species and should spur immediate action to address this threat.

Conclusion

The oceanic whitetip was proposed for a CITES Appendix II listing in 2010 that would have regulated international trade of the species, but the proposal fell a few votes short, with many countries arguing that sharks should be regulated through RFMOs instead of CITES. The IATTC Commission should protect this vulnerable species by prohibiting the retention of oceanic whitetips in all fisheries in the Convention area and requesting the immediate live release of any oceanic whitetip shark.

References

1. Inter-American Tropical Tuna Commission, “Fishery Status Report 8,” La Jolla, CA, 2010. <http://iattc.org/PDFFiles2/FisheryStatusReports/FisheryStatusReport8ENG.pdf>
2. Convention of International Trade in Endangered Species of Wild Fauna and Flora, “Consideration of Proposals for Amendment
of Appendices I and II: Proposal 16,” Fifteenth meeting of the Conference of the Parties, Doha (Qatar), 13-25 March 2010. <http://www.cites.org/eng/cop/15/prop/E-15-Prop-16.pdf>. Downloaded 19 May 2011.
3. L. R. Beerkircher et al., “Characteristics of Shark Bycatch Observed on Pelagic Longlines Off the Southeastern United States,
1992–2000,” Marine Fisheries Review, 64(4):40–9 (2002), http://findarticles.com/p/articles/mi_m3089/is_4_64/ai_n6148326.
4. S. Clarke et al., “Estimates of Shark Species Composition and Numbers Associated with the Shark Fin Trade Based on Hong
Kong Auction Data,” Journal of Northwest Atlantic Fishery Science, 35:453–65 (2004), <http://journal.nafo.int/35/35.html>.
5. M. Román-Verdesoto and M. Orozco-Zöller, “Bycatches of sharks in the tuna purse-seine fishery of the eastern Pacific Ocean reported by observers of the Inter-American Tropical Tuna Commission, 1993-2004,” Inter-American Tropical Tuna Commission Data Report 11, La Jolla, CA, 2005. <http://www.iattc.org/PDFFiles2/DataReports/Data-Report-11.pdf>
6. M. Román-Verdesoto and M. Orozco-Zöller, “Bycatches of sharks in the tuna purse-seine fishery of the eastern Pacific Ocean reported by observers of the Inter-American Tropical Tuna Commission, 1993-2004,” Inter-American Tropical Tuna Commission Data Report 11, La Jolla, CA, 2005. <http://www.iattc.org/PDFFiles2/DataReports/Data-Report-11.pdf>
7. Inter-American Tropical Tuna Commission, “Fishery Status Report 8,” La Jolla, CA, 2010. <http://iattc.org/PDFFiles2/FisheryStatusReports/FisheryStatusReport8ENG.pdf>
8. M. Román-Verdesoto and M. Orozco-Zöller, “Bycatches of sharks in the tuna purse-seine fishery of the eastern Pacific Ocean reported by observers of the Inter-American Tropical Tuna Commission, 1993-2004,” Inter-American Tropical Tuna Commission Data Report 11, La Jolla, CA, 2005. <http://www.iattc.org/PDFFiles2/DataReports/Data-Report-11.pdf>