It's already the fourth month since the introduction of my sea cucumbers to the pen. So as early as 0730, I swam into the 6,000 sq meter pond and I was shocked of what I saw: mass grave.
I was really, really surprised to see some dead sea cucumbers. It was really gruesome. In each pens, I saw four or five dead sea cucumbers and it looks like they were victims of a suicide bombing. Yeah, I think you have already surmised it right, their guts were open. Some of them were flat but all of their GI tract were missing. I first thought my sea cucumbers were attacked by those nasty crabs.
Since it was daytime, the recovery rate is lower since majority of them have already burrowed in the pond substrate. Just so you know, Holothuria scabra are nocturnal species. I still picked them even if they looked sick (or worse, dying).
I went back to land together with my research associate and did some measurements. I asked him whether my sea cucumbers were attacked by the predators and he said that the sea cucumbers in his pond, which is located a few meters from mine have also suffered the same predicament. They have this grayish discoloration on both of its ventral and dorsal side and secrete this slimy mucus from its anus and/or mouth.
According to the RA, this is probably caused by sudden changes in salinity and water temperature of the pond due to the abnormal weather. SEE? Because of El Niño, my thesis experiment has been compromised. I had the first sign of it last March 21, when one of the sea cucumbers eviscerated. You know, when sea cucumbers are subjected to stress, they vomit their own gut.
I will send this report to my thesis adviser later and wait for some possible actions to answer this serious quandary of mine. :(