1,721,153 research outputs found
Toxicology of marine mammals: new developments and opportunities
No full textIt is widely recognized that marine mammals are exposed to a wide variety of pollutants, with a weight of evidence indicating impacts on their health. Since hundreds of new chemicals enter the global market every year, the methods, approaches and technologies used to characterize pollution levels or impacts are also in a constant state of flux. However, legal and ethical constraints often limit the type and extent of toxicological research being carried out in marine mammals. Nevertheless, new and emerging in vivo, in vitro as well as in silico research opportunities abound in the field of marine mammal toxicology. In the application of findings to population-, species-, or habitat-related risk assessments, the identification of causal relationships which inform source apportionment is important. This, in turn, is informed by a comprehensive understanding of contaminant classes, profiles and fate over space and time. Such considerations figure prominently in the design and interpretation of marine mammal (eco)toxicology research. This mini-review attempts to follow the evolution behind marine mammal toxicology until now, highlight some of the research that has been done and suggest opportunities for future research. This Special Issue will showcase new developments in marine mammal toxicology, approaches for exposure-effect research in risk assessment as well as future opportunities
Heavy metals and organochlorine compounds in blood of a stranded Risso’s dolphins from Northern Adriatic Sea, Italy.
No full textPollutants play an important role in the crisis populations in dolphins. This long living mammals tend to accumulate contaminants because of the high lipidic composition of their tissues, their rank in the food chain and food preferences. Assessing pollutants concentrations can help to investigate the possible effect on the immune system and on the reproductive cycles of endangered species. Risso’s dolphin Grampus griseus is rarely present in shallow waters like Adriatic sea, where reprents about 4% of strandings (Mazzariol et al. 2007). Present work reports about the heavy metals and organochlorine compounds (organochlorine pesticides and PCBs) content in blood of a Risso’s dolphin stranded in summer 2007 in Northern Adriatic Sea. Samples were collected during rehabilitation cares and analysed with ICP-AOS and GC/MS techniques. Metals concentration found are close to those observed in a stranded Risso’s dolphin from Israel by Shohan et al. (2002) and are equal to 7.31 μg/ml for Hg, 0.05 μg/ml for Cd, 0.13 μg/ml for Pb and 0,40 for μg/ml for As. Interestingly Cu and Zn are below the limit of detection of the method. For organochlorine compounds, only some of the investigated organohalogen were detected: HCB (0.77 ng/ml), HCH (1.45 ng/ml), DDT (4.32 ng/ml). Concerning PCBs, congeners 118, 128, 157, 158, 167, 177, 180, 183, 192 and 201 were detected, always at the ng/ml level. Low levels of organochlorine compounds observed can be due to the poor conditions of the animal, who was starved and didn’t eat. This caused a loss of adipose tissue, a certain mobilisation of contaminants and their rapid excretion. The same consideration is valid for heavy metals. Actually there is a lack of comparing data and their interpretation can be speculative. Anyway, the combination of blood and tissues analysis will give more information and make these evaluation more easy
PRELIMINARY STUDY ON THYROID HORMONES EFFECT OF 4-NONYLPHENOL INTRAPERITONEALLY INJECTED TO ADULT MALES SHUBUNKIN (Carassius auratus, L.)
No full textCaratteristiche biometriche di una popolazione lagunare di anguilla europea (Anguilla anguilla) ai fini della selezione dei riproduttori
No full textTrace element concentrations in the Mediterranean monk seal (Monachus monachus) in the eastern Mediterranean Sea
No full textThe Mediterranean monk seal (Monachus monachus) is one of the most endangered marine mammals in the world. The biggest sub-population of the species survives in Greece, where understanding the effects of pollution on the survival of the species has been identified as a national research and conservation priority. From 1990 to 2013 we collected tissue samples from 59 deceased monk seals in order to: (i) Define the concentration of trace elements (As, Pb, Cd, Hg, Se, Cr, Ni) in three different matrices (i.e., blubber, liver and kidney), (ii) Determine whether differences in trace element concentrations are age- or gender-related, (iii) Evaluate the potential effects of these pollutants. The study recorded differences in trace element concentrations among matrices, but in general, trace element exposure in Mediterranean monk seals in Greece was low and within the non-acutely toxic levels for Pinnipeds. Only arsenic concentrations were at the upper limit of the normal range observed in other marine mammals (0.69 ± 0.55 mg/kg w.w. in blubber, 0.79 ± 0.62 mg/kg w.w. in liver and 0.79 ± 0.59 mg/kg w.w. in kidney). We recorded also exceptionally high Hg concentrations in a single adult female (24.88 mg/kg w.w.). Age- and gender-related differences were also recorded and were due to various biological, ecological and chemical factors. Based on the results of the study, potentially adverse effects on the immune and endocrine system of the Mediterranean monk seal from some pollutants (e.g., As, Cd, Se, Ni, Cr) cannot be ruled out, which may expose the Mediterranean seal population in Greece to epizootics and stochastic phenomena of mass mortality. It is therefore of utmost importance that pollutant monitoring becomes an integral component of the standard monitoring protocol of the endangered Mediterranean monk seal in the eastern Mediterranean
Monk seals (Monachus monachus) in the Mediterranean Sea: The threat of organochlorine contaminants and polycyclic aromatic hydrocarbons
Full text linkThe Mediterranean monk seal (Monachus monachus) is an emblematic species of conservation concern. Anthropogenic pressures have led to severe population declines and significant fragmentation of the remaining populations. Because of their close relationship with coastal areas, Mediterranean monk seals may be potentially exposed to pollution from agricultural sources, as well as from oil tanker spills. Although monitoring of pollution has long been considered a priority for this species, data on monk seal contamination levels are scarce. In this study, 55 blubber samples of all genders and age classes collected during necropsies (1995-2013) from seals of the Eastern Mediterranean subpopulation were analyzed for organochlorine compounds (OCs), i.e., hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDTs), and polycyclic aromatic hydrocarbons (PAHs). Overall, PCBs > DDTs ≫ PAHs > HCB in all samples. Results showed a significant downward trend over the 19-year period for DDTs and HCB. No marked pattern was found for PAHs, even though relative abundance of cancerogenic PAH fraction rose in recent years. PCB levels in subadult specimens increased noticeably over time despite worldwide ban. Our findings did not suggest recent releases of DDT or new pesticides (e.g., Dicofol) in the environment, but may indicate an improper disposal of ancient storages of PCBs or a remobilization from reservoirs. OC levels exceeded thresholds that are commonly associated with immunosuppression and reproductive impairment in other pinnipeds. Hence, OCs could be responsible of potential toxicological effects in this subpopulation. This study represents the first report on PAH and one of the few reports on OC bioaccumulation in Mediterranean monk seals. Based on the levels found in the blubber of monk seals from the Eastern Mediterranean, and given the known harmful effects associated to the prolonged exposure to these substances and the reduced long-term expectations of species recovery, regular monitoring is advocated
Messa a punto di un nuovo sistema per la riproduzione in cattività di Octopus vulgaris: performance riproduttive
No full textEspressioni comportamentali di adulti di Octopus vulgaris mantenuti in ambiente controllato
No full textGonadal Development in European Eel Populations of North Adriatic Lagoons at Different Silvering Stages
Full text linkThe European eel (Anguilla anguilla, Linnaeus 1758) is a catadromous fish with significant cultural, scientific, and commercial value. The protection of this species is particularly difficult because the biology of the eel life cycle remains unknown in many aspects. The European eel (A. anguilla) population has declined alarmingly over the past 30 years; this condition has led to questions about the long-term welfare of this species. This work aims to perform a histological analysis on gonad samples from European eels coming from four different lagoons of the North Adriatic at different stages of silvering, and to evaluate the maturation of the gonads. For this study, a total of 859 wild eels were captured from four different lagoons using the “lavoriero”. Subsequently, the biometric parameters were collected. Seventy-nine female eels were randomly selected, dissected, and the gonads were removed for histological analysis. Sections of 4 m were cut and stained with hematoxylin and eosin (H&E). Histological observations of germ cells at the light microscopy level allowed for the characterization of six steps of oocyte maturation. Valle di Comacchio had the highest levels of oocyte maturation, while Valle Ca’ Pasta had the lowest. Eels with silver index III had an oocyte maturation nearly equal to that of eels at stages IV and V of silvering. Considering the results, we can affirm that eels from North Adriatic lagoons have high oocyte maturation levels and high GSI value indices at silvering stage III. The following experimental work shows that the levels of oocyte maturation are higher even at lower silver index levels. It can be hypothesized that in these eels, the transition from yellow to silver eel occurs faster in relation to the high trophic availability in North Adriatic lagoons
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