Antonio Bellante

Impact of an acoustic stimulus on the motility and blood parameters of European sea bass (Dicentrarchus labrax L.) and gilthead sea bream (Sparus aurata L.)

The physiological responses of fish to underwater noise are poorly understood and further information is needed to evaluate any possible negative effects of sound exposure. We exposed European sea bass and gilthead sea bream to a 0.1-1 kHz linear sweep (150 dB(rms) re 1 microPa). This band frequency is perceptible by many species of fish and is mainly produced by vessel traffic. We assessed the noise-induced motility reaction (analysing the movements) and the haematological responses (measuring blood glucose and lactate, and haematocrit levels). The noise exposure produced a significant increase in motility as well as an increase in lactate and haematocrit levels in sea bream and sea bass. A significant decrease of glucose was only observed in sea bream. A linear correlation between blood parameters and motility in fish exposed to the noise was observed. The acoustic stimulus produced intense muscle activity.

Stranded cetaceans as indicators of mercury pollution in the Mediterranean Sea

Abstract Concentrations of Hg were determined in tissues (muscle, heart, kidney, lung and liver) of two cetacean species (Stenella coeruleoalba and Tursiops truncatus) stranded along the Italian coasts during the period 2000–2009 and compared with those previously reported by other authors from different areas of the Mediterranean basin. The highest concentrations of Hg were found in liver samples of both species (8.4-1752 mg·kg−1 dry weight for S. coeruleoalba and 9.6-1404 mg·kg−1 d.w. for T. truncatus). Statistically significant dissimilarities of Hg concentrations were recorded in muscle and liver tissues of S. coeruleoalba stranded in different geographical areas of the Mediterranean Sea as apparent direct response to uneven impacts of Hg pollution in the basin. A noteworthy outcome was that cetaceans stranded on the French coasts showed significantly higher levels of Hg contamination than those from other Mediterranean areas while the eastern part of the basin evidences the lowest Hg concentrations in the studied organisms. Moreover, the results of this study tentatively suggest the existence of different sub-populations of the two species in the basin.

Trace elements and vanadium in tissues and organs of five species of cetaceans from Italian coasts

Trace element concentrations (chromium, copper, zinc, iron, manganese and vanadium) were determined in organs of five species of cetaceans (Stenella coeruleoalba, Tursiops truncatus, Grampus griseus, Physeter macrocephalus, Ziphius cavirostris) that were found stranded along Italian coasts in the period 2000–2009. This dataset represents an important opportunity to verify and assess (particularly for V) patterns of incorporation of trace elements in different organs of cetaceans in a wide spectrum of species and related specimens distributed in all the age classes, and consequently determine the physiological and metabolic effects on the distribution modes of the same chemicals. In particular, Cu, Zn, and Fe accumulate preferentially in the liver of all studied specimens, while Mn and Cr values are found to be nearly constant in the analysed organs and tissues regardless of species. Comparable concentrations of trace elements, in different age classes, were measured for both specimens of S. coeruleoalba and T. truncatus (the most abundant dolphin species in the Mediterranean sea) in all analysed organs. On the other hand, unprecedented reported concentrations of V in tissues and organs of cetaceans from the Mediterranean show higher values when compared to levels measured in other marine mammals from the Atlantic Ocean.

Use of carbon and nitrogen stable isotopes to study the feeding ecology of small coastal cetacean populations in southern Brazil

Samples from individuals of the populations of Sotalia guianensis (Guiana) and Pontoporia blainvillei (Franciscana) dolphins living in the Babitonga Bay estuary (26° 28′ S/48° 50′ W), and samples from individuals of a second population of P. blainvillei from a nearshore area (26° 38′ S/48° 41′ W), were collected and analyzed along with their prey between 2000 and 2006, to determine the carbon and nitrogen stable isotope ratios and to verify differences in their feeding ecology. No differences were found in the median ð15N values of Guiana (15.2‰) and Franciscana (15.9‰) dolphins living in Babitonga Bay, nor of nearshore Franciscana (15.0‰) individuals, suggesting no variation in the trophic level of these populations. However, the lack of more information on the isotopic compositions of their putative prey in the nearshore areas prevents the ability to draw definitive conclusions on this issue. The estuarine Franciscana and Guiana dolphin populations presented mean ð13C values of approximately −15.7‰, which were not statistically different from nearshore Franciscana individuals (−14.8‰). Based on stomach content analyses of these species from a previous study, it was reported that there was little overlap in the diet of estuarine Franciscanas and Guiana dolphins. However, based on the similarity of the ð13C values between these two species and of their putative prey, it appears that in fact there is an overlap in the diet of these two species. Based solely on stable isotope analysis, it was not possible to differentiate between estuarine and nearshore Franciscana populations, making it difficult to conclude whether captured nearshore specimens were indeed yearlong residents of these areas. Finally, this study suggests that Franciscana and Guiana dolphin populations are sharing the same resources, mostly L. brevis, D. rhombeus, and S. rastrifer. Therefore, the combination of resource sharing and commercial exploitation of their prey makes these two cetacean species vulnerable.

Trace elements in tissues of sperm whales stranded along the Italian coast

Five sperm whales (Physeter macrocephalus) stranded along the Italian coast between 2007 and 2009 were analysed for concentrations of trace elements in the muscle, liver, kidney, lung, heart and skin. Essential elements (Zn, Cu, Fe, Cr, As, V and Se) show ranges of variability comparable with the limited data reported in the literature on this species and a homeostatic physiological control. Very low concentrations of nonessential elements (Hg, Cd and Pb) were detected in all tissues, suggesting a minor impact of these pollutants on the sperm whale populations of the Mediterranean Sea. This finding possibly reflects the pelagic lifestyle and deep-sea cephalopod diet of this group of giant cetaceans. In addition, this finding contrasts with the high levels of nonessential elements measured in many other species of cetaceans (e.g. Stenella coeruleoalba, Tursiops truncatus) stranded along Mediterranean coasts and which reflects significant coastal anthropogenic effects. The main result of this work is the compiled dataset which provides a preliminary target for conceptual understanding of the potential effects of open marine pollution on the Mediterranean sperm whale population.

Depredation of striped dolphin on squid fishery and behavioural responses to interactive pinger.

The depredation of dolphins on some artisanal fisheries in the Mediterranean Sea is the major source of economic loss. This study aims to reveal the behavior of striped dolphin during interaction with flying squid fishery equipped with interactive pinger in the Ionian Sea (southern Italy). A four channel acoustics acquisition system was used during fishing hauls to record the clicks and to localize the positions of dolphins through the time delay of arrival method. The preliminary analysis shows that dolphins approached the artificial light, used for attract the squids, diving further on 100 m below the fishing boat. The number and the power of dolphins’ clicks decreased after the signals emitted by the interactive pinger. The distances of dolphins from fishing boat do not seem change significantly before and after pinger emissions. Although the efficiency of DDD pingers to decrease the depredation level was demonstrated in some study, the functioning mechanism is still unknown. Our data could indicate th...

Some consideration about the management and economic aspect on the pinger use for mitigation the depredation phenomena in an MPA Mediterranean area.

This study was carried out in a fishing area off the coast of southern Italy, where Tursiops truncatus is frequently observed to interact with bottom gill nets. The experiments aimed to assess the economic efficiency of the DDD pingers during the interaction between dolphins and monofilament bottom gill nets. A net was equipped with pingers and another without to measure the different biomass catch and costs. The economic effectiveness with an estimate of the costs/benefits was evaluated. We modeled a catch per unit effort (CPUE) both in economic terms as euros per 50 m of net set and in biomass terms as kilograms caught per 50 m of net set with and without pingers. The analysis of the data allowed us to evaluate the advantage of the economic aid provided by the European Fisheries Fund (EFF) for the use of pinger. The CPUE of the net equipped with pingers was statistically higher than the control net. The costs of investment for pingers could fully comeback in 74 days and with the economic assistance of EFF in 34 days of fishing. The use of pingers represents productive and economic benefits, even if their potential impact noise should be considered.