Movement patterns of the parrotfish Sparisoma cretense in a Mediterranean marine protected area.

Understanding the movements of exploited fish has become a major concern for several management and conservation initiatives, such as the implementation of well designed marine protected areas. Movements of an important recreational target species from the Mediterranean Sea, the parrotfish Sparisoma cretense, were determined in a marine protected area using passive acoustic telemetry, to evaluate site fidelity and homing, quantify home range and identify temporal patterns. Six adult parrotfish (20.8-29.8 cm total length) were caught along the north-eastern coast of Lampedusa (Italy) and surgically implanted with acoustic transmitters. Three fish were caught and released at the same site within the integral (i.e. "no entry-no take") reserve, whereas the others were caught outside the reserve boundary and released at the mid reserve 0.5 km apart. Two of the three fish that were released away from the capture site demonstrated homing abilities. Four fish showed a strong site fidelity, whereas the others moved frequently in and out of the monitoring area. Home range sizes estimated over the period of monitoring (up to 207 days) varied from 70,387 to 256,398 m(2), with core areas of 16,688 to 84,946 m(2). Home range size did not differ significantly between day and night. Home ranges of all fish extended beyond the reserve boundaries, showing example of potential spillover into take zones. Temporal activity patterns of fish were diurnal with a dominant diel rhythm, likely due to a resting behaviour at night. Though not specifically designed to protect exploited fish, the marine reserve of Lampedusa seems adequate for the conservation and management of S. cretense.

Sewage pollution impact on Mediterranean rocky-reef fish assemblages.

The effects of sewage outfalls on subtidal fish assemblages were studied along the NW coasts of Malta (Sicily channel, Mediterranean Sea) by means of underwater visual census. The presence of two spatially distinct outfalls discharging untreated wastewaters allowed to use a balanced symmetrical after control/impact (ACI) design that consisted of two putatively impacted locations and two controls, with four sites nested in each location. Surveys were performed in 2006 at two random dates. The study highlighted significant changes at both assemblage and individual species levels. Fish assemblages structures were different between controls and sewages, where total abundance of fish were higher. The responses of individual species to sewage pollution were mostly related to an anomalous increase of two small opportunistic species i.e. Gobius bucchichii and Parablennius rouxi and to a decrease of species of the genus Symphodus, particularly S. roissali and S. ocellatus. Moreover in correspondence of the outfalls, significant changes of the fish size distribution were detected for several species. These results support the use of fish assemblages as biological indicators for marine coastal waters and demonstrated the possibility to obtain sharp signals of environmental impact from some individual fish species.