Date: 2016/11/04
Presentator: Bas Kooijman, representing Nina Marn
Site: Wageningen UR - Lumen  - gebouw 100  
Event: MilieuChemTox Symposium : Into the Great Unknown

Official title: 
Life cycle and ecology of the loggerhead turtle  (Caretta caretta, Linnaeus, 1758): Development and application of 
the Dynamic Energy Budget model

Short title: 
Exploring the effects of plastic ingestion on the energy budget of loggerhead sea turtles


Question driving my research was "What are the effects of plastic ingestion on loggerhead turtle's biology and ecology?". 
The overall aim was to provide new insights into processes important for the life cycle and ecology (growth, maturation, 
and reproduction) of this protected migratory species. 
Using the collected experimental and literature data, I developed a model based on the Dynamic Energy Budget theory that 
spans the full life cycle of the turtle. 
The model was then used to compare North Atlantic and Mediterranean populations, and to study the environmental 
(food density and temperature) and anthropogenic (plastic pollution) pressures on loggerhead turtles. 
Some of the results were surprising. I could explain from the differences in parameter values between both populations, 
why North Atlantic individuals that visit the Mediterranean See cannot reproduce there. The local population manages to do 
so by adaptation to the low level of food availability in this sea: they mature at a smaller size. This shows that this 
species lives at the edge of its capabilities, which also became visible in another more shocking way: the consumption of 
plastic lowers food intake. If plastic occupies only 3% of the stomage-gut capacity, this has already major effects on the 
ultimate size they can obtain and dramatically reduces reproductive output. 
Such volumes are already encountered in practice, highlighting the importance of responsible management of waste.