Large-Scale Assessment of Mediterranean Marine Protected Areas Effects on Fish Assemblages

Marine protected areas (MPAs) were acknowledged globally as effective tools to mitigate the threats to oceans caused by fishing. Several studies assessed the effectiveness of individual MPAs in protecting fish assemblages, but regional assessments of multiple MPAs are scarce. Moreover, empirical evidence on the role of MPAs in contrasting the propagation of non-indigenous-species (NIS) and thermophilic species (ThS) is missing. We simultaneously investigated here the role of MPAs in reversing the effects of overfishing and in limiting the spread of NIS and ThS. The Mediterranean Sea was selected as study area as it is a region where 1) MPAs are numerous, 2) fishing has affected species and ecosystems, and 3) the arrival of NIS and the northward expansion of ThS took place. Fish surveys were done in well-enforced no-take MPAs (HP), partially-protected MPAs (IP) and fished areas (F) at 30 locations across the Mediterranean. Significantly higher fish biomass was found in HP compared to IP MPAs and F. Along a recovery trajectory from F to HP MPAs, IP were similar to F, showing that just well enforced MPAs triggers an effective recovery. Within HP MPAs, trophic structure of fish assemblages resembled a top-heavy biomass pyramid. Although the functional structure of fish assemblages was consistent among HP MPAs, species driving the recovery in HP MPAs differed among locations: this suggests that the recovery trajectories in HP MPAs are likely to be functionally similar (i.e., represented by predictable changes in trophic groups, especially fish predators), but the specific composition of the resulting assemblages may depend on local conditions. Our study did not show any effect of MPAs on NIS and ThS. These results may help provide more robust expectations, at proper regional scale, about the effects of new MPAs that may be established in the Mediterranean Sea and other ecoregions worldwide.     

Coexistence of Low Coral Cover and High Fish Biomass at Farquhar Atoll,Seychelles

We report a reef ecosystem where corals may have lost their role as major reef engineering species but fish biomass and assemblage structure is comparable to unfished reefs elsewhere around the world. This scenario is based on an extensive assessment of the coral reefs of Farquhar Atoll, the most southern of the Seychelles Islands. Coral cover and overall benthic community condition at Farquhar was poor, likely due to a combination of limited habitat, localized upwelling, past coral bleaching, and cyclones. Farquhar Atoll harbors a relatively intact reef fish assemblage with very large biomass (3.2 t ha⁻¹) reflecting natural ecological processes that are not influenced by fishing or other local anthropogenic factors. The most striking feature of the reef fish assemblage is the dominance by large groupers, snappers, and jacks with large (>1 m) potato cod (Epinephelus tukula) and marbled grouper (E. polyphekadion), commonly observed at many locations. Napoleon wrasse (Cheilinus undulatus) and bumphead parrotfish (Bolbometopon muricatum) are listed as endangered and vulnerable, respectively, but were frequently encountered at Farquhar. The high abundance and large sizes of parrotfishes at Farquhar also appears to regulate macroalgal abundance and enhance the dominance of crustose corallines, which are a necessary condition for maintenance of healthy reef communities. Overall fish biomass and biomass of large predators at Farquhar are substantially higher than other areas within the Seychelles, and are some of the highest recorded in the Indian Ocean. Remote islands like Farquhar Atoll with low human populations and limited fishing pressure offer ideal opportunities for understanding whether reefs can be resilient from global threats if local threats are minimized.     

Targeting CB2-GPR55 Receptor Heteromers Modulates Cancer Cell Signaling

The G protein-coupled receptors CB₂ (CB₂R) and GPR55 are overexpressed in cancer cells and human tumors. Because a modulation of GPR55 activity by cannabinoids has been suggested, we analyzed whether this receptor participates in cannabinoid effects on cancer cells. Here we show that CB₂R and GPR55 form heteromers in cancer cells, that these structures possess unique signaling properties, and that modulation of these heteromers can modify the antitumoral activity of cannabinoids in vivo. These findings unveil the existence of previously unknown signaling platforms that help explain the complex behavior of cannabinoids and may constitute new targets for therapeutic intervention in oncology.     

Decline of Native Freshwater Fishes in a Mediterranean Watershed on the Iberian Peninsula: A Quantitative Assessment

We examined changes in the distribution of 9 native and 18 introduced freshwater fishes in the south-eastern Pyrenees watershed, Iberian Peninsula, using data from 1996, 1984–1988 and historical information. This region suffers many modifications to its freshwater ecosystems that are linked to human activity in the Mediterranean regions. Fish communities, stream physical habitat and environmental degradation were assessed at 168 sites from 11 basins in 1996. Seven native species (78%) showed decline from previous data, one of which became extirpated in the first half of the 20th century. On the other hand, introduced species are expanding. As a consequence, intact native communities are increasingly rare, declining from presence in 22% of river courses in 1984–1988 to 15% in 1996. The most typical community type is a mixture of native and introduced species occupying 30% of river courses. Stream degradation seems to be the main cause of this process because fish communities differed between degraded streams and streams suffering less impact. A principal component analysis showed that water pollution and modifications to the habitat were the two anthropogenic factors that accounted for most changes in the fish community integrity. Habitat alteration, primarily through construction of dams and water diversions, has fragmented habitats and isolated native fish communities in headwater streams. Current protection measures do not offer effective conservation of threatened species and communities. A global conservation and restoration programme from an ecosystem-based approach is essential to reverse the trend affecting native freshwater fishes in this Mediterranean region.     

Oryctes rhinoceros populations and behavior influenced by a baculovirus

Oryctes rhinoceros adults stopped feeding and flew less frequently, and the males mated less often after they became infected with the baculovirus of Oryctes. Monitoring the larval and adult population in Western Samoa over several years gave evidence that the incidence of the virus is dependent on the density of the O. rhinoceros population. Male beetles were more frequently infected than female bettles. Adding more virus-infected beetles to the O. rhinoceros populations of Nukunonu Atoll, where the virus had become established 5 years earlier, reduced the population significantly. The data indicated that the reduction was caused mainly by a decrease in the number of eggs deposited.     

Enhanced excretion rates induced by small-scale turbulence in Acartia (Copepoda: Calanoida)

Several experiments have been performed on three congenericspecies of the calanoid copepod Acartia to determine the effectsof small-scale turbulence on metabolic rates. Both inorganicnitrogen and phosphorus excretion rates significantly increased     

Adenosine deaminase affects ligand-induced signalling by interacting with cell surface adenosine receptors

Adenosine deaminase (ADA) is not only a cytosolic enzyme but can be found as an ecto-enzyme. At the plasma membrane, an adenosine deaminase binding protein (CD26, also known as dipeptidylpeptidase IV) has been identified but the functional role of this ADA/CD26 complex is unclear. Here by confocal microscopy, affinity chromatography and coprecipitation experiments we show that A₁ adenosine receptor (A₁R) is a second ecto-ADA binding protein. Binding of ADA to A₁R increased its affinity for the ligand thus suggesting that ADA was needed for an effective coupling between A₁R and heterotrimeric G proteins. This was confirmed by the fact that ASA, independently of its catalytic behaviour, enhanced the ligand-induced second messenger production via A₁R. These findings demonstrate that, apart from the cleavage of adenosine, a further role of ecto-adenosine deaminase on the cell surface is to facilitate the signal transduction via A₁R.