In summary, ACAP (2021) describe strategic offal discharge as good practice, a supplementary rather than a primary mitigation measure, and recommend that:
- offal and discards should not be discharged during line setting;
- during line hauling, offal and used baits should preferably be retained or discharged on the opposite side of the vessel from that on which the line is hauled; and
- all hooks should be removed and retained on board before discards are discharged from the vessel.
With regard to sharks, offal management includes the practices of chumming during setting or discarding of offal during hauling. However, little is known of the impact upon shark catch rates of these practices.
A recent (2007, 2008) study of 12 pelagic longline fisheries from eight countries found very few fishers who believed that refraining from chumming during the set and refraining from discarding offal and spent bait during the haul would affect shark interactions. It was found that chumming during setting was not a common practice and that offal and spent bait were typically discarded during hauling operations. Many of those interviewed explained that it would be impractical to retain spent bait and offal to discard at the end of hauling due to limited space on the vessels.
Further information needed on opportunities and constraints for the application of offal management in pelagic fisheries (short and long term).
- ACAP. 2011. AC5 Annex 7 - Summary advice statement for reducing impact of pelagic longline gear on seabirds. Fourth Meeting of the Seabird Working Group, Guayaquil, Ecuador. SBWG-4 Doc 12.
Birdlife International (2014) Bycatch Mitigation Fact-Sheet 12. Demersal and Pelagic Longline: Haul mitigation. English, Japanese, Korean, Portuguese, Simplified & Traditional Chinese.
- Gilman, E., Clarke, S., Brothers, N., Alfaro-Shigueto, J., Mandelman, J., Mangel, J., Petersen, S., Piovano, S., Thomson, N., Dalzell, P., Donoso, M., Goren, M. and Werner, T. 2007. Shark depredation and unwanted bycatch in pelagic longline fisheries: Industry practices and attitudes, and shark avoidance strategies. Western Pacific Regional Fishery Management Council, Honolulu, USA.
- Gilman, E., Clarke, S., Brothers, N., Alfaro-Shigueto, J., Mandelman, J., Mangel, J., Petersen, S., Piovano, S., Thomson, N., Dalzell, P., Donoso, M., Goren, M. and Werner, T. 2008. Shark interactions in pelagic longline fisheries. Marine Policy 32(1): 1-18.
- ACAP. 2021. ACAP Review of mitigation measures and Best Practice Advice for Reducing the Impact of Pelagic Longline Fisheries on Seabirds. In: ACAP - Twelth Meeting of the Advisory Committee. Online