I've just returned from a two and a half week trip onboard shark longliner. The shark longline fleet in South Africa is pretty small, only 3-4 vessels, which mainly fish for mako sharks. The gear set up of the vessel is slightly different but the fishing techniques are very similar to the swordfish and tuna longliners (that is using long line with 1,000 - 1,300 baited hooks).
Jose, the skipper, welcomed me with a big smile and a promise that we wouldn't catch any birds on this trip. I've heard these kind of promises before. But, this time, Jose kept his promise and we returned back to shore with empty bags - which is always excellent.
We lost half a day due to bad weather, but still managed to collect some valuable data. We were experimenting for the first time the efficiency of circle hooks compared to J-hooks. We also studied the hooks' sinking rate which affects the seabird bycatch greatly (the faster the line sinks, the less time albatrosses and petrels have to steal it).
It was very interesting to see that despite large numbers of birds around the boat most of the trip no birds were caught on the line.
On the way to the fishing grounds and back we tested the bird-scaring lines (tori lines). Jose came up with some nice ideas and together we are going to design a slightly different version to fit his vessel and hopefully the rest of the fleet.
I want to thank Jose and the crew for an excellent trip. It is always exciting to work people who care for sea and its inhabitants with a great passion.
We sailed to the south, and the sea is very agitated and I'm worried because maybe we won't set today. A day without working means one more day at the sea, which makes the fishermen upset. But I carry on testing different techniques to help save albatrosses.
The fishing productivity was not so good, lots of seabirds around... many sea turtles and rays captured. We recovered a piece of the tori line that broke during the last setting. I think that we must improve and do some corrections at the cables used at the FV Camburi to avoid the entanglement... The angle in relation with the water line is less than 45º and the height of the cable is smaller because of this. The Skipper agreed to make a simple change.
Beaufort scale 5: I think that we won't set the longline. Everything depends on the weather.
However - yes, the skipper decided to set the longline and and so we use a pair of tori lines. The weather is pretty bad, but if we must test, let's test...
At the very beginning of the set, one of the tori line cables became entangled with the main line of longline and broke, losing 50 % of its length.
The good news that the tori line's cable easily broke, and, for my relief, it didn't cause any damage to the main longline.