The FV Joao N Castro leaves port today and I will be going with her.
Over the past couple of months I have been preparing for this important trip, which is the first of a series of at-sea experimental trials to test new line-weighting in the demersal (bottom) longline fishery here in Namibia. The captain of the Joao N Castro has agreed to collaborate with the ATF to compare 5 kg steel weights with the standard concrete weights that all the vessels in this fishery use.
The image below shows Namibian crew members loading the 5 kg steel weights
The problem with concrete weights is that they get damaged quickly and loose mass, resulting in slow-sinking gear. Effective line weighting is the most important factor of best practice mitigation for demersal longline fishing and we are thrilled to be testing this under commercial conditions in this fishery. By making a direct comparison with standard gear, we will be able to measure the sink rate, identify the level of seabird bycatch and fish catch associated with different weighting configurations.
Changing line weighting configurations is one technique captains use to target fish, depending on whether they want to fish close to, or off the seabed. It is important that our study can quantify the fish catch as well as the bird bycatch so that we can find the best case scenario for all concerned. Collaborating with industry from an early stage is really important in our work, as it means any mitigation measures resulting from our experiments are accepted much faster by the captains and crew who use them.
I will provide updates as the experiment progresses!
Image: The FV Joao N Castro in Walvis Bay