Search results for " Fish"

Pinger affects fish catch efficiency and damage to bottom gill nets related to bottlenose dolphins

2009

There is some evidence that the presence of Tursiops truncatus in fishing areas represents a real economic threat to fishermen due the dolphin feeding on the entangled fish, damaging the nets and reducing the fish catch. We have carried out experiments to assess the efficiency of a pinger in decreasing the interaction between the dolphins and fishing nets, in a fishing area off the coast of southern Italy, where Tursiops truncatus is frequently observed to interact with bottom gill nets. Two identical monofilament bottom gill nets (900 m long), one equipped with pingers and the other without, were used to measure the effect of these pingers on the abundance of the catch and net damage. For …

By-catch of cetaceans and other species of conservation concern during pair trawl fishing operations in the Adriatic Sea (Italy)

2010

By-catch is one of the main sources of anthropogenic mortality in marine species of conservation concern worldwide. Between 2006 and 2008, the Consorzio Nazionale Interuniversitario per le Scienze del Mare (CoNISMa) coordinated a monitoring programme of cetacean by-catch in Italian pelagic trawlers, funded in compliance with European Regulation 812/2004. Sixteen independent observers monitored a total of 3141 hauls. The observation coverage ranged between 0.9 and 6.3% of the regional fishing effort. Almost all by-catch events were recorded in the northern Adriatic Sea. By-catch rates of bottlenose dolphins (Tursiops truncatus) and loggerhead turtles (Caretta caretta) were 0.0006 and 0.0255 …

A Mediterranean record of Eulalia ornata (Annelida: Phyllodocidae) corroborating its fidelity link with the Sabellaria alveolata-reef habitat

2015

Among marine habitats Sabellaria alveolata -reefs deserve protection since they provide important ecosystem services and positive effects on biodiversity. Several marine species are listed among the S. alveolata -reef associated fauna, but characteristic species were seldom reported. Eulalia ornata (Annelida, Phyllodocidae) might represent an exception, since it appears common/abundant in S. alveolata -reefs of the Eastern Atlantic. The most evident geographical mismatch in the distributions of E. ornata and these biogenic reefs occurs in the Mediterranean Sea, where S. alveolata -reefs are commonly found, but E. ornata was never recorded, whilst E. viridis , a non-Mediterranean species, wa…

Transplantation assessment of degraded Posidonia oceanica habitats: site selection and long-term monitoring

2014

A model developed for Zostera marina was adapted and used to select suitable areas for Posidonia oceanica transplantation in the Gulf of Palermo, where recent rehabilitation programmes have reduced human pressure. This model consists of three steps: (1) habitat selection, by calculation of the Preliminary Transplant Suitability Index (PTSI); (2) field assessments and test-transplanting, to evaluate the site suitability and to estimate the effects of tearing on transplant units (about 50%); (3) identification of suitable restoration sites, by calculation of the Transplant Suitability Index (TSI). A new parameter was added to the literature model: the number of grids detached, which is linked…

Valuing the unmarketable: an ecological approach to the externalities estimate in fishing activities

2013

In a rapidly changing world, sustainability, if it can be said to exist at all, is concept that has attained mythic status, often pursued and rarely reached. In order to improve our capability to cope with environmental problems, adopting an Ecosystem Approach has been suggested. One of the major challenges in the implementation of this new paradigm relates to control of externalities. The recognition and quantification of externalities is often cast as valuing the unmarketable, and there are several approaches that have been proposed. Here, we analyze the opportunity to “feed” the economic valuation with ecological concepts. From an ecological perspective, the energy required to sustain a …

Tracking multiple pathways of waste from a northern bluefin tuna farm in a marine-coastal area.

2011

Aquaculture of bluefin tuna in Mediterranean coastal waters has generated growing concern about the negative environmental effects. In the present isotopic study we examined the dispersal and fate of organic matter derived from a Mediterranean tuna farm in the surrounding environment. An overall enrichment in the heavy nitrogen isotope was found in the feed and in farmed tunas, indicating the input of isotopically traceable organic matter in the system. Waste was clearly traceable in the water column up to 1000 m from the cages, while only slight accumulation occurred in the sediment just below the cages. Waste was isotopically shown also to contribute to the diet of demersal and benthopela…

Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

2015

According to the Intergovernmental Panel on Climate Change report released in September 2014, unprecedented changes in temperature and precipitation patterns have been recorded globally in recent decades and further change is predicted to occur in the near future, mainly as the result of human activity. In particular, projections show that the Mediterranean climate zone will be markedly affected with significant implications for lake water levels and salinity. This may be exacerbated by increased demands for irrigation water. Based on long-term data from seven lakes and reservoirs covering a geographical gradient of 52 of latitudes and a literature review, we discuss how changes in water le…

PESCA SOSTENIBILE E CONSERVAZIONE DELLA NATURA IN SICILIA

2014

Screening of ecotoxicological, qualitative and reproductive variables in male European sea bassDicentrarchus labrax(L.) reared in three different fis…

2013

The aim of this work was to do a preliminary seasonal screening of ecotoxicological biomarkers in European sea bass Dicentrarchus labrax in three different fish farms, to know if the different location and typology can discriminate them. A set of selected biomarkers of xenobiotic exposure, such as acetylcholinesterase (AChE) activity, Glutathione (GSH) and gonad morphology were investigated seasonally in male European sea bass D. labrax (L.) reared in three different intensive farms: a land-based farm of cement tanks (T), an in-shore sea cages farm (C1) and an off-shore sea cages farm (C2). The results showed that both location and typology can discriminate AChE activity, GSH content and go…

Effects of Ocean Acidification on physiology, behaviour and ecology of fish

CO2 concentration in the atmosphere is increasing at unprecedented rate since the last 800,000 years due to rising fossil fuel combustion, industrial processes and land use by humans. By absorbing part of this gas from the atmosphere, Oceans contribute to the mitigation of climatic changes, but at the cost of greater modifications of their physical and chemical characteristics. CO2 dissolved in the seawater leads to increased bicarbonate (HCO3 -) and hydrogen ions (H+) concentrations with a consequent pH drop, a phenomenon known as Ocean Acidification (OA). If global policy will not put in force mitigation measures to reduce CO2 emissions, it is projected that partial pressure of dissolved …