RECCAM PROJECT. Field work (July 2015)

From 27^th June to 17^th July, a group of RECCAM researchers and students were on their first campaign of the project. We sampled eight Posidonia oceanica meadows along the Spanish Mediterranean Coast, from Cap de Creus (Catalunya) to Águilas (Murcia). We also simulated mechanical perturbation at different levels in fixed plots which will be monitored over the next few years. The sampling was also focused on the salerma fish (Sarpa salpa), one of the main herbivore in Western Mediterranean macrophyte communities. We conducted visual transects and recorded the shoal feeding behavior. 

This field trip was certainly loaded with work but also it was hightly productive and rewarding.

Evaluating potential artifacts of tethering techniques by Jordi Boada

Field experimentation is one of the ways that ecologist have to test how nature works. Along the history of ecology, a wide range of techniques have been developed and are now available for young scientist to enhance their work in the field. Hairston, Underwood, Heck and many others have enormously contributed to experimental design in marine ecosystems and have discussed on how to apply experimental methods to contrast hypothesis. The aim of experimental ecology is to measure processes without introducing biases to the results for instance related to the presence of the experimentalist in the field.

In recent years, some members of our group have focused their efforts on understanding the predation process between predatory fish and the sea urchin Paracentrotus lividus. For this reason we have been using tethering methods to tag the sea urchins in the field. The most common method to tag sea urchin species is to pierce them using a hypodermic needle. In our new work published in the Journal of Experimental Marine Biology and Ecology we have tested whether piercing can either increase the mortality or the detectability of the tagged sea urchin. With this study, we have shown that tethering through piercing is perfectly useful to test predation under most common conditions in the field. If this technique is properly used, there is no risk to increase the mortality and detectability of the sea urchin at all. 

Schematic description of the methodology used.