Emilio Sperone

Toxicity of Foroozan crude oil to ornate wrasse (Thalassoma pavo, Osteichthyes, Labridae): ultrastructure and cellular biomarkers

Abstract The present study was conducted to assess the toxicity of Foroozan (Iranian crude oil) on the ornate wrasse Thalassoma pavo (Labridae) using three sub-lethal crude oil concentrations. Gills, selected as target organ being the major route of hydrocarbon uptake, were excised after 48, 96 and 192 hours and analyzed by light and both scanning and transmission electron microscopy. Cellular biomarkers of exposure and/or effect were measured in branchial tissues of T. pavo, and severe lesions such as necrosis, aneurysms and disorganization of the lamellae proportional to the Foroozan exposure periods and concentrations were observed. The main alteration was on the lamellar epithelium, which displayed an irregular profile characterized by pavement cell cytoplasmic protrusion and an alteration of the oxygen chemosensing cells, resulting in impairment of various biological activities. Nevertheless, the ability of specimens to regulate calcium homeostasis and neurotransmission, as well as balance cell turnover, suggests that the species tested to not only survive but also recover in such high crude oil dosage regimen. The identification in gills of histological and neurological changes associated with acute crude oil exposure confirms the utility of the sub-lethal toxicity tests.

Survival, development, and gonadal differentiation in Rana dalmatina chronically exposed to chlorpyrifos

Chlorpyrifos is an organophosphate pesticide among the most widely used in the world, which is suspected to be an endocrine-disrupting compound. To determine the capacity of chlorpyrifos to affect gonadal differentiation in Rana dalmatina, tadpoles were exposed to this pesticide during larval development until completion of metamorphosis at ecologically relevant concentrations (0.025 and 0.05 mg/L). No effects of chlorpyrifos exposure on survival, development, or metamorphosis were observed. After a 1 month metamorphosis, the gonadal phenotype was determined by gross morphology and histological examination. Morphological and histological analysis revealed normal ovaries or testes in froglets belonging to control group, whereas testes from several froglets exposed to chlorpyrifos were interspersed with testicular oocytes in histological sections. Chlorpyrifos exposure during the entire larval period did not affect sex ratio, but reduced the percentage of males with histologically normal testes. The findings suggest that chlorpyrifos exposure has significant effects on gonadal differentiation in some animals by inducing an intersex condition and alterations to testicular morphology, and that R. dalmatina is sensitive to endocrine disruption. Thereby, this study provides evidence that the ecologically relevant concentrations of chlorpyrifos, although not adversely affect the survival, development, or metamorphosis, may interfere with sex differentiation and reproductive development of R. dalmatina via endocrine-disrupting mechanisms.

Social interactions among bait-attracted white sharks at Dyer Island (South Africa)

Abstract The goal of this preliminary research was to provide an ethogram of social interactions among white sharks at Dyer Islands Nature Reserve (Gansbaai, South Africa) in the presence of bait. Eighty-three social interactions were observed, both from a boat and from a cage. Seven different interaction types were recognized: swim by; follow give way; follow; parallel swimming; give way; splash fights; and piggybacking. The preliminary data analysis did not reveal any significant relationship between the behavioural patterns and the sex of the sharks, but a strong correlation between behavioural patterns and the size of the animals was found. The observed displays were more often performed by animals of the same length than by animals of different size.

The shift from aquatic to terrestrial phenotype in Lissotriton italicus: larval and adult remodelling of the skin.

Morphology and ultrastructure of the skin of Lissotriton italicus (previously named Triturus italicus) have been described in different phases of its biological cycle: larval stage, metamorphic stage and adult stage with emphasis on modifications occurring between aquatic and terrestrial adults. In the present study, light microscopy and both scanning and transmission electron microscopy were employed to analyze the histological and cytological remodelling that occurs in the skin of L. italicus during metamorphosis. The ultrastructure of the larval epidermis is arranged into three principal layers comprising an external layer of pavement cells, a basal layer and 1-3 intermediate layers consisting of Leydig cells along with accessory cells and mitochondria-rich cells. By the onset of metamorphosis, morphological changes of the skin include stratification and flattening of epidermal layers and disappearance of typical larval cells. In both aquatic and terrestrial adult phases the thin, cornified epidermis shows the same general arrangement as found in other vertebrates with an external stratum corneum and a variable number of intermediate cell layers. During the terrestrial adult phase, the skin is characterized by the presence of numerous tubercles; moreover, the lower epithelium is thicker than in the aquatic phase. Ultrastructural analysis revealed no substantial differences in the cellular composition of the skin between aquatic and terrestrial phases.

Morphology and ultrastructure of the gills in two Urodela species: Salamandrina terdigitata and Triturus carnifex

Gill morphology and ultrastructure are described for Triturus carnifex and Salamandrina terdigitata with emphasis on differences occurring between two species that inhabit different aquatic biotopes. The morphology and ultrastructure have been studied using light microscopy and both scanning and transmission electron microscopy. The general organization of the gills is similar in the two species and shows the characteristics of Urodela larvae in which the gills consist of three tufts of filaments supported by gill arches III, IV and V. However, some differences are noticeable in the length of the main filament and in the number of secondary lamellae: in T. carnifex, a pond‐dwelling salamander, the main filaments are long and rich in secondary lamellae; in the stream‐type larva of S. terdigitata, the main filaments are shorter and show a lower number of secondary lamellae, located in its proximal portion. The cellular composition of the gill filament and of respiratory lamellae is different in S. terdigitata: in the gill filament basal cells, pavement cells, ciliated cells, club‐shaped cells, mitochondria rich cells (MRCs) and Leydig cells have been recognized, while in the secondary lamellae the last cellular type does not appear. On the contrary, in T. carnifex we observe the same cellular composition in both filament and secondary lamellae.

Amphibians of the Pollino national park: Distribution and notes on conservation

Abstract Information is given on the distribution and ecology of amphibians in the Pollino National Park, based on a summary of the data contained in the Herpetology Laboratory database at the Ecology Department (University of Calabria) and updated with information obtained during recent sampling. A total of 412 stations was monitored revealing the presence of 11 amphibian species. Two of these (Bombina pachypus, Salamandrina terdigitata) are included in annex II and six (Rana italica, R. dalmatina, Hyla intermedia, Bufo viridis, Triturus italicus, T. carnifex) in annex IV of the ‘Habitat’ directive. Some species represent interesting Italian (T. carnifex, H. intermedia), Apennine (B. pachypus, R. italica, S. terdigitata) and southern Italian (T. italicus) endemisms, which further valorize the heritage of the Parks fauna. For each species the state of conservation was checked and evaluated in order to propose suitable strategies for protection.

Genetic differentiation and phylogeography of Mediterranean-North Eastern Atlantic blue shark (Prionace glauca, L. 1758) using mitochondrial DNA: panmixia or complex stock structure?

Background The blue shark (Prionace glauca, Linnaeus 1758) is one of the most abundant epipelagic shark inhabiting all the oceans except the poles, including the Mediterranean Sea, but its genetic structure has not been confirmed at basin and interoceanic distances. Past tagging programs in the Atlantic Ocean failed to find evidence of migration of blue sharks between the Mediterranean and the adjacent Atlantic, despite the extreme vagility of the species. Although the high rate of by-catch in the Mediterranean basin, to date no genetic study on Mediterranean blue shark was carried out, which constitutes a significant knowledge gap, considering that this population is classified as “Critically Endangered”, unlike its open-ocean counterpart. Methods Blue shark phylogeography and demography in the Mediterranean Sea and North-Eastern Atlantic Ocean were inferred using two mitochondrial genes (Cytb and control region) amplified from 207 and 170 individuals respectively, collected from six localities across the Mediterranean and two from the North-Eastern Atlantic. Results Although no obvious pattern of geographical differentiation was apparent from the haplotype network, Φst analyses indicated significant genetic structure among four geographical groups. Demographic analyses suggest that these populations have experienced a constant population expansion in the last 0.4–0.1 million of years. Discussion The weak, but significant, differences in Mediterranean and adjacent North-eastern Atlantic blue sharks revealed a complex phylogeographic structure, which appears to reject the assumption of panmixia across the study area, but also supports a certain degree of population connectivity across the Strait of Gibraltar, despite the lack of evidence of migratory movements observed by tagging data. Analyses of spatial genetic structure in relation to sex-ratio and size could indicate some level of sex/stage biased migratory behaviour.

Surface behaviour of bait-attracted white sharks at Dyer Island (South Africa)

Abstract Six research expeditions were conducted at Dyer Island to observe the surface behaviour of white sharks in the presence of bait. Observations were made from a commercial cage-diving boat. We observed 140 white sharks that exhibited 9 different types of behaviour: parading, bait following, visual inspection, breach, tail slap, tail stand, spy hop, repetitive aerial gaping, and head-up vertical emerging. Breach and tail slap were most often performed by male sharks, and tail slap and tail stand were more often performed by mature animals. The ethogram consisted of an average of 20 behavioural units, with a significant transitional pattern from bait follow to parading and from parading to bait follow. The individual surface behaviour of white sharks is not a simple stimulus–response reflex, but rather a complex tactical situation in which animals show plastic responses. Many aspects of white shark surface behaviour resemble those of other predator species that spend time at the surface.

Evidence of Sperm Storage in Nursehound (Scyliorhinus stellaris, Linnaeus 1758): Juveniles Husbandry and Tagging Program

Nursehound, Scyliorhinus stellaris (Linnaeus 1758), is a shark of the Scyliorhinidae family, close to the Scyliorhinus canicula (Linnaeus 1758), frequently hosted in public aquaria. Information on biology and ecology is deficiently available regarding this species of sharks. In the Mediterranean basin, they are occasional rare and vulnerable species (Serena, 2005). In 2003 a female specimen of Scyliorhinus stellaris, 90 cm long, fished in the Tyrrhenian Sea was transferred to Tuscany Argentario Mediterranean Aquarium and placed in a 20.000 L tank. The female laid 42 eggs and juveniles were born on 2004 and 2005. They were transferred to the aquarium laboratory in order to get standard protocol for correct juveniles husbandry. After a total of 18-month observations, some of them were tagged and let free on 2006. To collect data about nursehound shark needs in terms of feeding and growing in captivity, especially during the first life years, is a necessary and fundamental step in order to develop a Mediterranean program of tagging and study in the field of conservation policy proposal. Husbandry protocol for this species’ juveniles was developed in this study. This is the first reported case of a nursehound storing sperm for 2 years, in captivity (Pratt, 1993; Hamlett et al., 2002; Awruch, 2007).