One of the species targeted by the deep sea fisheries in the southeast Atlantic is the splendid alfonsino (Beryx splendens). This fish forms very large schools at deep depths over seamount ridges and is mainly caught by mid-water trawls, but also by bottom trawls and longlines (see images below) *.
Last week during our stop at the Wüst seamount we caught a small number of splendid alfonsino in our mid-water trawl net so I finally had the chance to have a better look at these beautiful fish. And they are actually amazing! They have a brilliant scarlet red color, which is quite striking, and have large eyes.
Their eyes are especially interesting because like other deep sea species, they have a very wide dark pupil that is surrounded by a reddish iris. These fish, and others like them, have a reflecting surface in the eye known as the 'tapetum lucidum', which increases the amount of light they can see and so they are able to exist in dark environments. Other nocturnal animals, such as cats and dogs, have a similar layer and that is why you can see their eyes shining when illuminated at night.
Splendid alfonsino are very vulnerable to overfishing because of their slow growth rates and, compared to some other fish, they take a long time to mature. Therefore, by studying the splendid alfonsino we caught at Wüst seamount we can help deep sea managers develop sustainable management policies for these fish.
*For more information on different types of fishing gear: http://www.fao.org/fishery/fishtech/search/en "
05/02/2015