Sea turtle nesting season (March – October) is upon us and with 70% of the nation’s sea turtle nesting sites occurring in Florida, we are looking forward to a busy season! Already, 5 nests have been found in south Florida by the Broward County Sea Turtle Conservation Program. Leatherback sea turtles (Dermochelys coriacea, critically endangered) start the nesting season off in March , followed by loggerhead sea turtles (Caretta caretta, threatened) in April, and green sea turtles (Chelonia mydas, endangered) in the end of May. A single female may re-visit the same beach to lay her eggs several times during the nesting season before taking a one or two year hiatus.
So what are sea turtles doing when not laying close to 100 golfball-sized eggs on the beach? Eating jellyfish!
Leatherback sea turtles are the largest sea turtle species growing to 7 feet long and 2,000 lbs. As one of the worlds’ most migratory species, leatherbacks can swim 10,000 miles from nesting beaches to high latitude feeding grounds in search of their primary food source, jellyfish. But how can such a large marine athlete survive on a gelatinous diet? By knowing where to find the all-you-can eat jellyfish buffet!
Scientists from the Dalhousie University, Nova Scotia, Canada suction cupped animal-borne video cameras to leatherback sea turtles to describe foraging behavior and to estimate daily caloric intake. The videos reveal that leatherbacks consume up to 16,000 calories in jellyfish! That is equivalent to 664 lion’s mane (Cyanea capillata) and moon jellies (Aurelia aurita) or around 73% of their body weight.
The jellies’ stinging nematocysts are no match to the leatherback’s spine-lined mouth and throat, which, funny enough closely resembles the Sarlacc Pit in the Return of the Jedi. Because of their specialized spines, leatherback sea turtles never miss a jelly and since lion’s mane and moon jellies are found in large smacks (blooms) during the summer months in Canadian waters, these sea turtles literally swim into their food. So for these ultra swimmers, a lot of jelly goes a long way!
Heaslip, Iverson, Bowen & James (2012) Jellyfish Support High Energy Intake of Leatherback Sea Turtles (Dermochelys coriacea): Video Evidence from Animal-Borne Cameras. PLoS ONE http://dx.doi.org/10.1371/journal.pone.0033259