Within the Dutch Caribbean, green and hawksbill turtle rookeries and foraging grounds are found. Green and hawksbill turtles have been decimated by human exploitation and habitat degradation, calling for knowledge of population structure and demographic history. Here we investigate migration patterns in these highly migratory species and evaluate current population status. In other words: How many turtles were there and where to they go? Those are the central questions in my PhD which I will address using population genomics and ancient DNA.
Last summer I’ve spent three months in the Dutch Caribbean collecting tissue samples for my research. Most samples were collected on Bonaire, but a significant amount were collected on Curacao as well. A few samples were collected on Aruba as well. As soon as the samples arrive I will start on DNA extractions and analyses! Jurjan van der Zee
Last week we* successfully placed a satellite transmitter on a big green turtle female after she nested at Little Curacao’s turtle beach. The signals of the ARGOS satellite are updated hourly and I am very happy to report that this female is swimming very fast in the direction of Nicaragua 1050km in the first 10 days. Continue reading “Little-Curaçao-green-turtle swims 3100 km in 3 weeks”
Two weeks ago we arrived on Bonaire. Since then we worked non-stop and we made great progress! The first thing we did was to set up a turtle exclosure experiment on the seagrass beds in Lac Bay, after Funchi (STCB) and Sabine Engel (STINAPA) kindly showed us all the suitable seagrass areas. The native dominant seagrass species here are Thalassia testudinum (or turtle grass) and Syringodium filiforme. However after a quick snorkel survey across the bay the cover of invasive seagrass species Halophila stipulacea seems almost higher.
I am very excited to finally start our fieldwork on sea turtles and seagrass in the Bonaire, Aruba and Curacao! What started as a proposal (initiated by Lisa Becking and me) in August 2013, finally resulted in a research project May 2015 entitled “Ecology and conservation of Green and Hawksbill turtles in the Dutch Caribbean”. Continue reading “Sea turtle fieldwork in Dutch Caribbean 2015”
Who eats who in the Wadden Sea? We collected 12000 samples in one of the largest dbases of stable isotope samples. Using these samples we found that the energy in the Wadden Sea (primary production) is mainly provided by the production of benthic algae (diatoms) on the tidal flats. Papers about this are underway but the first results can be found in our scientific report & glossy
The Wadden Natuur kaart (Wadden Sea Nature Map) is now online: this is one of the publications of the Waddensleutels project on which I worked in the last 2+years. You should definitively explore and test it. For example; activate the benthos hotspot layer (upper left) and see which areas are most interesting as foraging areas for birds. Or check out where intertidal musselbeds occured for 5 years or more (in last 17 years). Or combine a map of shrimp fishery intensity and biodiversity. Our newly developed habitat map allows you to do these analysis per habitat type. Have a go at it. Use this interactive map to make your own map using just your web browser, print it or download it or continue in a GIS program. In the photo you see Han Olff & Sander Holthuijsen exploring the map at a large touch screen during the symposium in Leeuwarden.
The Waddensleutels project finished 16 april 2015 with a symposium in Leeuwarden, and with that also my 1st post-doc project. Topics here were: Which measures should we take to increase the area of musselbeds in the Dutch Wadden Sea & what is the current foodweb stucture and state (and how is this affected by the presence of mussel beds)? We learned that mussel beds are of vital importance for the Wadden sea. Musselbeds increased the biomass of benthos, fish and birds upto 4 times compared to bare surrounding areas. Mussel beds really are the foundations of life in the Wadden Sea.