A STINKY DECOMPOSING MESS OR AN UNDERWATER FEAST?

November 27, 2015 by Meredith Thornton Research Coordinator, Dyer Island Conservation Trust

It’s all a matter of opinion!

Just the other day, 25 November, the whale watching/eco trip vessel, Dreamcatcher, from Dyer Island Cruises stumbled upon a dead whale that had already stated turning white due to decomposition. The skin was falling off and the stench had started. It wasn’t possible to figure out which species it was, but from the shape of the flippers it was definitely not a humpback or a southern right whale. It also wasn’t possible to determine the cause of death.

The only thing that could be done was to record the latitude and longitude and to take a tissue sample for DNA analysis that will hopefully help us to determine what sort of whale it was. That night wind was blowing strongly onshore so the chances were big that it might drift ashore. This is not a problem if it is in an uninhabited area, but you can imagine how residents will complain about a 40 ton rotting mass upwind of their lovely beachfront home! I’m sure that the Municipality were praying overnight for currents to sweep it offshore again! If it were a fresh specimen then I would have been willing it in the other direct so that it would come ashore so that we could collect a full set of measurements, tissue and reproductive samples for the Mammal Research Institute and possibly skeletal remains for the South African Natural History Museum.

Fortunately though, it hasn’t come ashore as yet! While no shark activity was noticed, there were some bite marks present, as well as several holes from blackbacked gulls that were pecking away on their floating dinner plate! Once the decomposition gases have leaked out then the whale carcass will sink to the ocean bottom, known as WHALE FALL. In our shallow coastal waters the carcass will be utilised fairly quickly…scavenging sharks, lobsters, crabs, hagfish and a whole multitude of worms and amphipods will gorge themselves, dining night and day on this blubbery treasure. This might sound pretty gross to you and me, but to these creatures it is literally a gift from above.

A whale falling to bottom in deeper waters, like off the continental shelf, may provide food for many years. Once ruling the top of the food chain while it was alive, the dead whale now forms the basis of a whole new ecosystem on the ocean floor…and so the cycle of life begins again!

DID YOU KNOW? Historically, the first people that lived along the shores of South Africa used to live off the intertidal zone, and when they found a fairly fresh stranded small whale or dolphin they would bury the carcass in the intertidal zone where the meat was more more-or-less preserved in the moist, saline environment, and that way they could have access to nutrient-rich meat over a long period of time. Whale, dolphin and seal meat and fat is rich in healthy omega fats, meaning that people who consume this type of fatty meat have no problems with cholesterol!