Present distribution of common dolphin Delphinus delphis in French Mediterranean and adjacent waters as obtained from small boat surveys

1. Common dolphin distribution in the western Mediterranean is still poorly known, with the exception of the Alboran Sea. In French waters, the species occurrence is suspected to have strongly decreased during the 20th century.
2. Small boat dedicated surveys from 1988 to 2012 were undertaken to describe common dolphin distribution in five regions of French waters and three southern regions of the western basin. A total survey effort of 38,561 km resulted in sightings of 25 common dolphin groups in the western basin.
3. Common dolphins were rarely observed off the French continental coast, more frequently around Corsica, and were quite frequent in waters off western Sardinia. Their most favoured habitat was found to be in neritic or upper slope waters.
4. The analysis of stranding records suggested that common dolphins were more abundant in French inshore waters prior to 1980.
5. A major increase of pelagic fish landings occurred from the beginning of the 1960s in the western part of French waters. Local populations of common dolphins may have declined as a consequence of prey depletion.

     

Bottlenose dolphins in the north-western Adriatic Sea: Abundance and management implications

1. The Adriatic Sea is one of the Mediterranean areas most heavily impacted by fishing and other human stressors. The northern part of the basin has been certified as an Important Marine Mammal Area because of the regular occurrence of common bottlenose dolphins, Tursiops truncatus.
2. Boat surveys, totalling 76 days at sea and 10,711 km of navigation, were conducted between April 2018 and October 2019 to assess cetacean abundance within a 3,000-km² area off Veneto, Italy. Bottlenose dolphins – the only marine mammal species observed – were encountered on 52 days and were tracked for 81 h and 26 min, resulting in 15,066 dorsal fin photographs of high quality and resolution.
3. Various capture–recapture models were applied on individual photo-identification datasets. Model-based estimates indicate that approximately 600 individuals occurred within the study area during the sampling period in both years. Abundance varied monthly: minimum estimates were obtained in May 2018 (291 individuals; 95% CI 134–630) and May 2019 (121; 95% CI 20–721), whereas maximum estimates were obtained in September 2018 (385; 95% CI 310–477) and October 2019 (494; 95% CI 378–645).
4. Evidence provided by this study can be used to complement and validate coarse ‘snapshot’ information from recent aerial surveys of the entire Adriatic Sea, and to enforce management action mandated by the European Community (EC) Habitats Directive and Marine Strategy Framework Directive, as well as guiding the EC’s Maritime Spatial Planning.

     

Marine mammal stranding response in Mexico: Lessons learned

1. Marine mammals are indicators of ecosystem health, and thus stranding records are an invaluable information source. The response to marine mammal stranding (RMMS) must be comprehensive, taking into account three components: (i) operations, (ii) research, and (iii) information dissemination. Although RMMS had previously been practised in several coastal locations in Mexico, the recent enforcement of a new regulation for RMMS has posed a challenge to actors as they adapt to it.
2. To understand the functioning of RMMS in Mexico, Bahía Todos Santos and Bahía de La Paz, two localities with over 20 years of experience in RMMS, were selected. To achieve this goal, a document review to identify the actors involved and their functions was undertaken together with a social network analysis to identify relevant actors in each locality and semi-structured interviews to identify key topics for RMMS.
3. The composition of the involved actors was similar at both locations. Some actors were found to have mandatory functions (i.e. governmental actors), while others (i.e. civil society organizations) performed functions beyond those established in official documents. Governmental agencies, the academic sector, and civil society organizations were the most connected actors and could help disseminate information, facilitate communication within the network, and influence decision-making.
4. The main topics identified were, in order of relevance: (i) economic constraints; (ii) actors' involvement; (iii) stranding response logistics; and (iv) recognition among actors.
5. In conclusion, several limitations to the RMMS exist at both localities, mainly related to the lack of economic resources, but actors involved in RMMS actions are motivated by their own interests. This study proposes the integration of actors into local networks that take into consideration the biological, physical, and social characteristics of each place.

     

Conservation management of common dolphins: Lessons learned from the North-East Atlantic

1. The short-beaked common dolphin is one of the most numerous cetacean species in the North-East Atlantic and plays a key functional role within the ecosystem as a top predator. However, in 2013, its conservation status for the European Marine Atlantic, under Article 17 of the Habitats Directive, was assessed as ‘Unfavourable-Inadequate’. Of key concern for this species is fishery bycatch, with pollution also being an issue. There are, however, major knowledge gaps concerning the extent of the effects of such pressures on the species.
2. Implementation of national observer bycatch programmes and bycatch mitigation measures under EC Regulation 812/2004 has been important. The responsibility for this is currently being transferred to the EU fisheries Data Collection Framework and Technical Measures Framework, the potential advantages and disadvantages of which are discussed. Collection of data and samples through national stranding schemes in some countries has enabled assessments of life-history parameters, dietary requirements, and the effects of stressors such as pollutants.
3. Nevertheless, in order to improve the conservation status of the North-East Atlantic population, a number of key actions are still required. These include the implementation of a species action plan, finalization of a management framework procedure for bycatch, and coordination between member states of monitoring programmes. It is important that there is monitoring of the state of the common dolphin population in the North-East Atlantic management unit through regular surveys spanning the range of the management unit, as well as continued assessment of the independent and interactive effects of multiple stressors. Above all, conservation status would be improved through application and enforcement of existing legislation in European waters.
4. This paper provides a summary of the current state of our knowledge of common dolphins in the North-East Atlantic along with recommendations for conservation management that may also be relevant to the species in the Mediterranean Sea.

     

Harbour porpoises exhibit localized evasion of a tidal turbine

1. Tidal energy generators have the potential to injure or kill marine animals, including small cetaceans, through collisions with moving turbine parts. Information on the fine scale behaviour of animals close to operational turbines is required to inform regulators of the likely impact of these new technologies.
2. Harbour porpoise movements were monitored in three dimensions around a tidal turbine for 451 days between October 2017 and April 2019 with a 12-channel hydrophone array.
3. Echolocation clicks from 344 porpoise events were localized close to the turbine. The data show that porpoises effectively avoid the turbine rotors, with only a single animal clearly passing through the rotor swept area while the rotors were stationary, and none passing through while rotating.
4. The results indicate that the risk of collisions between the tidal turbine and porpoises is low; this has important implications for the potential effects and the sustainable development of the tidal energy industry.

     

Epidemiology of Bartonella Infection in Rodents and Shrews in Taiwan

During the period of August 2002 and November 2004, an epidemiological investigation for Bartonella infection was conducted in small mammals in Taiwan. Using whole blood culture on chocolate agar plates, Bartonella species were successfully isolated from 41.3% of the 310 animals tested. The isolation rate of Bartonella species varied among different animal species, including 52.7% of the 169 Rattus norvegicus, 28.6% of the 126 Sucus murinus, 10% of the 10 Rattus rattus and 66.7% of the three Rattus losea. Bacteremia prevalence also varied with the origin of the animals, as 56.2% of the animals captured on farms, 38.6% of the ones captured at harbour sites and 11.8% of the animals captured from urban areas were bacteremic. Through molecular analysis of the gltA gene and 16S/23S intergenic spacer region, genetic diversity of Bartonella organisms was identified, including strains closely related to Bartonella tribocorum, Bartonella grahamii, Bartonella elizabethae, Bartonella phoceensis and Bartonella rattimassiliensis. Moreover, this is the first report of zoonotic B. elizabethae and B. grahamii identified in R. losea, the lesser rice‐field rat. Various Bartonella species were identified in R. norvegicus, compared to 97.2% of Suncus murinus with unique Bartonella species. By indirect immunofluorescence antibody test, using various rodent Bartonella species as antigens, consistently low percentage of seropositivity implied that small mammals may play a role as competent reservoirs of Bartonella species in Taiwan. Future studies need to be conducted to determine whether these Bartonella species would be responsible for human cases of unknown fever or febrile illness in Taiwan, especially zoonotic B. elizabethae and B. grahamii.     

Infection with Toxoplasma gondii during Pregnancy: Seroepidemiological Studies in Austria

Seropositivity among pregnant woman in Austria has decreased from 48% to 50% at the end of the 1970s to 35% in recent years. Despite this decrease, knowledge of possible sources and risk factors for Toxoplasma infection remains important. We reviewed seroepidemiological studies that were undertaken to assess the roles of undercooked meat and oocysts in cat faeces as potential sources of infection in pregnant women. Improved management and hygiene in pig herds raised in confinement have resulted in less contact of pigs with cats and a decrease of infected pigs within one decade from 14% in 1982 to 0.9% in 1992. In Austrian wild boar populations, however, seroprevalences remained essentially unchanged during the same decade (18% in 1983 and 19% in 1990–1993). Austrian sheep and goats are usually kept on small farms where cats abound and are predominantly seropositive (66% in sheep and 69% in goats). The seroprevalence in cats has decreased from approximately 81% in 1987 to 59% in 1996; presumably because of cats’ increased consumption of processed food. Despite the decrease of infection in pregnant women via the cat‐to‐pig pathway, it may be offset by a recent concomitant increase in mutton consumption. Free‐ranging chickens are a good indicator of the prevalence of T. gondii oocysts in the soil because chickens are ground feeders. Antibodies to T. gondii, as evaluated by the modified agglutination test, were found in 36% of chickens from 12 Austrian ‘biofarms’. Because Austrians rarely consume raw pork, the fraction of human T. gondii infections associated with pig meat consumption is likely small. As meat consumption and lifestyle patterns change in Austria, the risk of human infection with T. gondii via different pathways needs re‐evaluation and targeted educational efforts to control transmission.