By satellite phone I contact Oli Yates, ATF Coordinator to report on progress. I am somewhere in the south Indian Ocean having joined a reefer ship in Singapore. So far I've been at-sea for just over a week. My destination is a longline vessel fishing for Blue fin tuna in the Indian ocean. The task in hand is to perform experimental trials to investigate how the addition of weight to branch lines affects target fish catch and the bycatch of vulnerable seabirds like albatross and petrels.
Tuna longline vessels set thousands of hooks per day, each attached to the end of branch lines that hang vertically from the main line, like so many branches extending from the trunk of an immensely long thin tree. Main lines stretch out over the sea surface for tens of kilometres held close to the surface by buoys. Each branch line can be 40 m long and are typically made from transparent monofilament line, which is invisible in water. Tuna are visual predators and so it is important that the baited hooks appear to be drifting free in mid-water.
On many vessels these lines hold no weights to help them sink. The thinking behind this is that the inclusion of weights on the line may be highly visible to tuna and therefore dissuade them from taking the baited hook. This is a crucial point for seabird conservation, as the slow sinking hooks float at the surface for a long time where albatrosses can readily attack and swallow them. The line then slowly sinks with the fishing gear and the seabirds are dragged slowly underwater to drown.
This is the first time an ATF instructor has the opportunity to board a longline vessel in a high-seas fishery. High-seas refers to fisheries that are based in international waters beyond the jurisdiction of any countries' Economic Exclusion Zones. These fisheries are governed by Regional Fishery Management Organisations (RFMOs), where the governments of several countries collaborate to manage the fishery. The fact that the ATF is able to board a high-seas vessel is thanks to the advocacy work performed through the Global Seabird Programme (GSP) who regularly attend RFMO meetings to drive the inclusion measures in fishery regulations to prevent seabird bycatch.
Thanks to the work of the GSP, the five tuna RFMOs that overlap with vulnerable seabirds now require mitigation measures.This is an excellent example of how the GSP model works, with top-down advocacy and bottom-up grass roots work through the ATF coming together to save the albatross.
Hopefully, it will be possible to give regular updates on progress over the next weeks!
Below: A typical high-seas tuna vessel. Source: marinetraffic.com