More discoveries onboard
Work continues at a hectic pace aboard the Nansen on days 7 and 8 of the third leg.
Over the past days, we’ve been surprised by the amazing number of parasites infesting the fish we are studying. In particular, we noted a recurrence of an isopod of the genus Ceratothoa that we often found on the black seabeam, Spondyliosoma cantharus.
It is also impressive to see how the quickly the isopod can determine that something is going wrong with its host. As soon as the fish it has attached itself to is out of the water, the isopod, which is often immobile, immediately moves in search for another host.
Today we also focused a little bit more on biological work undertaken onboard.
- Parasites found on our samples (Isopods commonly found on black seabeam)
Once the fish is all on deck, we select specimens of target species before proceeding with the determination of sex, maturity stage and fullness of stomach.
Our fellow scientist and dear friend Alioune, who is an expert in maturity stage determination, provided excellent on-the-job training for those of us not familiar with these practices.
He patiently extracted and displayed the gonads of Sardina pilchardus so that we could all help with this analysis.
- Our fellow scientist, Alioune, from Mauritania, demonstrates and explains to us the process of maturity stage determination
- Display of gonads to determine sex and maturity
Day 8 started with two trawls where we could see different species.
- Puffer fish, Lagocephalus sp.
- Raja miraletus
During the next shift Alioune tested scientists on knowledge gained the previous day during our training session. Our FAO colleague Deborah recognized 27 maturity stages out of 30 - an excellent result that illustrates the quality of the maturity stage determination training provided.
Next, Said, a Moroccan biologist, explains to us to the extraction of otholits on a scombridae. Otholites are bones located in the head of fishes that allow, with the same methods used for threes, to determine the exact age of a fish.
- Said demonstrating the extraction of otholits
- Said, a Moroccan biologist, at work
- Said demonstrating how otholits determine the exact age of a fish
Finally Madiabel, from Senegal, punched the recorded data on Nansis.
- Our Senegalese colleague Madiabel ensures all our data is documented
And what could be better, after a long day of work, than nature’s beautiful gift to us of a spectacular sunset as we approached the coast of Morocco?
- One of the pleasures of life at sea