07.06.2018 – Islands of life

Our traditional boat embarked on a rather long afternoon tour today, with a group of very friendly guests on a windy Atlantic ocean. The gusty conditions made it particularly hard for our team to locate cetaceans out at sea, which unfortunately lead us to return to the marina with no sighting.

The choppy ocean, however, did not stop the two young Loggerhead turtles (Caretta caretta) we encountered, from basking at the waters surface. After all, the sun was still shining and the juvenile reptiles needed to warm up before plunging back into the blue depths. We always make note of turtle encounters and make photos of the animals before transferring the data to local biologists. Individual turtles are generally best identified through the facial pattern on their cheeks but can also be recognized through other characteristic features, such as the pattern of biological growth or “epifauna” on their shells.

Epifauna is the collective term for sessile marine animals that grow and thrive on a substrate. For such epifauna, a range of species that includes barnacles and tube worms, and also for a number of mobile species such as crabs life begins as a larvae that is part of the zooplankton at the surface. Unlike holoplankton, the microscopic animals that are planktonic their entire lives such as krill, meroplankton only form part of plankton communities during their larval stage before experiencing metamorphosis and growth. In order for this development to take place they need a substrate, which in the open ocean can range from living creatures, such as turtles, to floating objects such as plastic waste, boats or buoys. These islands of life are also often used as a temporary refuge by several fish to hide from potential predators.