VU Research Portal
Life cycle and ecology of the loggerhead turtle (Caretta caretta, Linnaeus, 1758):
development and application of the Dynamic Energy Budget model Marn, N.
2016
document version
Publisher's PDF, also known as Version of record
Link to publication in VU Research Portal
citation for published version (APA)
Marn, N. (2016). Life cycle and ecology of the loggerhead turtle (Caretta caretta, Linnaeus, 1758): development and application of the Dynamic Energy Budget model.
General rights
Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.
• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.
• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ?
Take down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
E-mail address:
vuresearchportal.ub@vu.nl
Download date: 17. Oct. 2021
The specific aim of my research was to answer a simple question "What are the effects of plastic ingestion on loggerhead turtle's biology and ecology?". The overall aim was to provide new insights into biology and ecology of this protected migratory species.
I focused on the processes important for the life cycle and ecology (growth, maturation, and reproduction). My methods included using the collected experimental and literature data, developing a life cycle model based on the Dynamic Energy Budget (DEB) theory, and using the model to compare North Atlantic and Mediterranean populations, and to study the the environmental (food density and temperature) and anthropogenic (plastic pollution) pressures on loggerhead turtles.
By far the most shocking result was the effect of plastic ingestion on the energy budget of loggerhead turtles, however several other results deserve attention as they provide valuable insight into the biology and ecology of loggerhead turtles. The analyses of the three life stages and two neighbouring North Atlantic subpopulations resulted in recommended carapace conversion formulae (for specific life stages as well as the whole size span) and highlighted in which cases the discovered morphological differences between life stages might play an important role. Comparison of individuals from Mediterranean and North Atlantic populations explored the effect of the environment and the effect of population-specific physiological traits (reflected as population-specific parameter values) on various life history traits, growth, maturation, and reproduction of loggerhead turtles. Analysis of the estimated (population-specific) DEB parameters and their implied properties, as well as analysis of the cases when model predictions deviate from the measured data, suggest posthatchlings might maximize their growth during the first several weeks, individuals might allocate energy to reproduction earlier than thought, and the ontogenetic habitat shift might be resulting in a bi-phasic growth curve. Finally, plastic ingestion affects the individuals similar to food dilution, resulting in small ultimate size and no reproduction when it occupies over 14% of the digestive system volume. When a several times longer residence time of ingested plastic than that of food is assumed, the effect is similar (small ultimate size and no reproduction) already when plastic occupies 3% of the digestive system volume.
Keywords: DEB, loggerhead turtle, mechanistic model, environmental changes, plastic ingestion, Mediterranean, North Atlantic
