Four PhDs of the ECOMERS laboratory presented their work on 28 of January 2019. You will find hereafter a summary and a PDF of their presentation.

Alexandre Schickele: Climate induced distribution shifts: the case of European small pelagic fishes

Predicting future climate induced shifts on marine species distribution has become an important challenge for sustainable resource and ecosystem management. Our study aims to investigate the potential distribution changes of the most harvested small pelagic fish (SPF) species in the Mediterranean Sea. Species distribution models have been extensively used to over last years to investigate potential future distribution shifts. However, no consistent framework to calibrate and evaluate these models exists. Therefore we developed a comprehensive numerical procedure based on recent scientific advances, allowing a better consideration of sampling biases and improving the modelled distribution. Both temperature mean and variability appear as the major factors driving SPF’s distribution. Regardless of the emission scenario, the models converge toward a decrease in climate suitability in the Mediterranean Sea for SPF, leaving the Adriatic Sea and the Gulf of Lion as the last suitable areas in case of a pessimistic scenario such as RCP8.5. Link to presentation

Eugenio Di Franco: Impact of noise pollution on the development and settlement of coastal fish juveniles

The undersea environment has long been depicted as a silent world. Research carried out in the last decades, however, has raised a growing awareness about sounds and noises as important components of the marine environment. The raise of global industrialization and trading has resulted in a dramatic increase in anthropogenic noises at sea. Coastal areas, in particular, are experiencing an unprecedented increase in human population, urbanisation, industrial and touristic settlements. Most of these activities generate or contribute to the so- called “noise pollution”. There is increasing evidence that anthropogenic noise may impact a large variety of marine animal species. The effects of anthropogenic noise on marine organisms can range from very weak effects to immediate death. The aim of this thesis will be to test whether behavioural, morphological and physiological variables of juvenile sparid fish are affected by different levels of anthropogenic noise, with the objectives of better understand its biological impact on marine organisms to ecosystems. Link to presentation

Elena Desidera: Characterization of the spawning aggregations of the Dusky grouper, Epinephelus marginatus (Lowe, 1834) in the Marine Protected Area of “Tavolara - Punta Cavallo” (Sardinia, NW Mediterranean)

The Dusky grouper, Epinephelus marginatus, is an ecologically and economically valuable fish, highly vulnerable to overfishing due to slow growth rates, late sexual maturity, protogynous hermaphroditism and reproduction via spawning aggregations. Fishing caused dramatic declines in density and size of this fish in many areas of the Mediterranean Sea. Nowadays, this species is abundant only in Marine Protected Areas (MPAs), where its spawning aggregations are mostly documented. This multi-disciplinary project aims at investigating the effect of protection measures on Dusky groupers’ spawning aggregations in the MPA of “Tavolara-Punta Cavallo” (Sardinia). These spawning aggregations are characterized by collecting and analyzing data about i) the historical local ecological knowledge of the species, ii) abundance, iii) reproductive-related behaviours, and iv) courtship-related sound production patterns of Dusky groupers at the study sites. The project will help support monitoring and management programs to protect this endangered species during a vital phase of its life cycle. Link to presentation

Elisabeth Riera: An easy method to assess 3D underwater habitat complexity

It is a common theme in ecology that 3D habitat complexity begets faunal diversity and abundance. However, complexity is a parameter that still remains difficult to assess in the field, especially underwater. Most studies employ qualitative or semi-quantitative measures, which limits comparison between them. Recently, we have developed a method to quantitatively assess the complexity; we computed an index providing a quantitative measure of the abiotic complexity of habitats. First, based on the rugosity and the surface–volume ratios of the structure, which define the structure refolding degree important for the settlement of sessile species. Secondly, based on Shannon diversity computed on the habitat cavities that define shelter for mobile species. Those parameters can be measured directly underwater and can also be computed on a digital model representing the 3D structure of the habitat. First results on fictive 3D models and artificial reefs 3D models give promising perspectives. Link to presentation

Since several years, ECOMERS collaborates with IUCN within several specialist groups. Several contributions to the Red List have been produced (see the complete list in the "Read more" section). In November 2018, the IUCN Red List of Threatened Species published the new global assessments on Groupers. ECOMERS contributed to the status evaluation 6 of these species: the White Grouper (Epinephelus aeneus), the Dogtooth Grouper (E. caninus), the Goldblotch Grouper (E. costae), the Dusky Grouper (E. marginatus), the Haifa Grouper (Hyporthodus haifensis) and the Mottled Grouper (Mycteroperca rubra).

Two species are considered as Data Deficient, E. caninus, E. costae, two as Least Concern, H. haifensis, M. rubra, one as Near Threatened, E. aeneus, and one as Vulnerable, E. marginatus. The previous status of E. marginatus, the most important species within the Mediterranean basin, was Endangered. This change from EN to VU status does not prove that there are some improvements of the status of the dusky grouper. The population trend is clearly decreasing on its whole geographic distribution. However, the change in status from the previous assessment reflects an improved application of the IUCN Red List Categories and Criteria, as well as a better understanding of available data. It means that further research is needed on its population status, especially in the southwestern Indian Ocean, the southwestern Atlantic and West Africa, and actions that reduce fishing effort are greatly needed. Similarly in the Mediterranean, more research efforts have to be deployed to assess the current fishing effort on this species.

It is also important to highlight that these 2018 status evaluations for the Grouper species are global, i.e. considering their whole geographical distribution. At a regional scale, the Mediterranean, the present status of the Dusky Grouper is still Endangered.