scholarly journals Determinants of lungworm specificity in five cetacean species in the western Mediterranean

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Rachel Pool ◽  
Clara Romero-Rubira ◽  
Juan Antonio Raga ◽  
Mercedes Fernández ◽  
Francisco Javier Aznar
Keyword(s):  
Bottlenose Dolphins ◽  
Parasite Burden ◽  
Western Mediterranean ◽  
Host Size ◽  
Cetacean Species ◽  
Stenella Coeruleoalba ◽  
Species Similarity ◽  
Pilot Whales ◽  
Common Dolphins ◽  
Prey Overlap

Abstract Background Current data about Pseudaliidae show contrasting patterns of host specificity between congeneric species. We investigated how both contact and compatibility between hosts and parasites contributed to the patterns of lungworm infection observed in a community of five species of cetaceans in the western Mediterranean. Methods The lungs of 119 striped dolphins Stenella coeruleoalba, 18 bottlenose dolphins Tursiops truncatus, 7 Risso’s dolphins Grampus griseus, 7 long-finned pilot whales Globicephala melas, and 6 common dolphins Delphinus delphis were analysed for lungworms. Parasites were identified by morphology and analysis of ITS2 sequences using both maximum likelihood and Bayesian inference methods. Body length was used as a proxy for lungworm species fitness in different hosts and compared with Kruskal-Wallis tests. Infection parameters were compared between cetacean species using Fisher’s exact tests and Kruskal-Wallis tests. Phylogenetic specificity was explored by collating the overall lungworm species prevalence values in hosts from previous surveys in various localities. To explore the relative importance of vertical and horizontal transmission, Spearman’s rank correlation was used to look for an association between host size and lungworm burden. A Mantel test was used to explore the association between lungworm species similarity and prey overlap using dietary data. Results Halocercus delphini had higher infection levels in striped dolphins and common dolphins; Stenurus ovatus had higher infection levels in bottlenose dolphins; and Stenurus globicephalae had higher infection levels in long-finned pilot whales. These results are congruent with findings on a global scale. Morphometric comparison showed that the larger nematodes were found in the same host species that had the highest parasite burden. Lungworms were found in neonatal striped dolphins and a Risso’s dolphin, and there was a weak but significant correlation between host size and parasite burden in striped dolphins and bottlenose dolphins. There was also a weak but significant association between prey overlap and lungworm species similarity. Conclusions Data indicate that phylogenetic specificity has an important role in governing host–parasite associations, as indicated by the higher infection levels and larger nematode size in certain hosts. However, diet can also influence infection patterns in these preferred hosts and contribute to less severe infections in other hosts.

Host specificity ofOschmarinella rochebruniandBrachycladium atlanticum(Digenea: Brachycladiidae) in five cetacean species from western Mediterranean waters

2010 ◽  
Vol 85 (1) ◽  
pp. 12-19 ◽  
Author(s):  
P. Mateu ◽  
J.A. Raga ◽  
F.J. Aznar
Keyword(s):  
Host Species ◽  
Bottlenose Dolphins ◽  
Western Mediterranean ◽  
Its2 Region ◽  
Single Individual ◽  
Common Dolphin ◽  
Cetacean Species ◽  
Stenella Coeruleoalba ◽  
Pilot Whales ◽  
Common Dolphins

AbstractWe investigated patterns of specificity of liver flukes (fam. Brachycladiidae) in a community of cetaceans from the western Mediterranean. The liver and pancreas of 103 striped dolphins,Stenella coeruleoalba, 18 Risso's dolphins,Grampus griseus, 14 bottlenose dolphins,Tursiops truncatus, 8 common dolphins,Delphinus delphis, and 5 long-finned pilot whales,Globicephala melas, were analysed for brachycladiid species. Two species were found:Oschmarinella rochebruniin striped dolphins (prevalence (P): 61.2%; mean intensity (MI) (95% CI): 34.2 (25.7–45.6)), andBrachycladium atlanticumin striped dolphins (P: 39.8%; MI: 7.1 (4.8–13.1)) and a single individual of common dolphin (P: 12.5%; intensity: 19), which represents a new host record. A molecular analysis using the internal transcribed spacer 2 (ITS2) region of the rDNA gene confirmed that specimens ofB. atlanticumwere conspecific regardless of host species. Available dietary data suggest that Risso's dolphins, bottlenose dolphins and long-finned pilot whales would contact rarely, if at all, the infective stages ofO. rochebruniandB. atlanticum. Neither the prevalence nor the mean abundance ofB. atlanticumdiffered significantly between striped and common dolphins, but a principal component analysis using seven morphometric variables indicated that specimens collected from the common dolphin were stunted. These worms also had fewer eggs compared with specimens typically found in striped dolphins, although the size of the eggs was similar in both host species. Dwarfism and low fecundity have typically been found in helminths infecting unusual host species, and might reflect the lower compatibility ofB. atlanticumfor common dolphins. In summary, bothO. rochebruniandB. atlanticumappear to exhibit a narrow specificity for striped dolphins in the western Mediterranean.

Stomach contents of English Channel cetaceans stranded on the coast of Normandy

2005 ◽  
Vol 85 (6) ◽  
pp. 1539-1546 ◽  
Author(s):  
J.F. De Pierrepont ◽  
B. Dubois ◽  
S. Desormonts ◽  
M.B. Santos ◽  
J.P. Robin
Keyword(s):  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Stomach Contents ◽  
Important Species ◽  
Stenella Coeruleoalba ◽  
Delphinus Delphis ◽  
Common Squid ◽  
Pilot Whales ◽  
The University ◽  
Common Dolphins

During 1998–2003 stomach contents of 47 marine mammals stranded on the coast of Normandy were analysed. The animals were first examined by a veterinary network and stomach contents were analysed at the University of Caen. The sample comprised: 26 common dolphins (Delphinus delphis), four bottlenose dolphins (Tursiops truncatus), seven harbour porpoises (Phocoena phoecoena), five grey seals (Halichoerus grypus), two long-finned pilot whales (Globicephala melas), one white beaked dolphin (Lagenorhynchus albirostris), one minke whale (Balaenoptera acurostrata) and one striped dolphin (Stenella coeruleoalba). The identification of food items was done using hard parts (i.e. fish otoliths and cephalopod beaks). Diet indices were computed including prey frequency and percentage by number. Common dolphins ate mainly gadoid fish (Trisopterus sp.), gobies and mackerel (Scomber scombrus). Cephalopods occurred in small numbers in the diet and commercially important species (cuttlefish and common squid) were scarce.

Cetacean stranding and diet analyses in the North Aegean Sea (Greece)

2017 ◽  
Vol 98 (5) ◽  
pp. 1011-1028 ◽  
Author(s):  
C.B. Milani ◽  
A. Vella ◽  
P. Vidoris ◽  
A. Christidis ◽  
E. Koutrakis ◽  
...  
Keyword(s):  
Bottlenose Dolphins ◽  
Aegean Sea ◽  
Cetacean Species ◽  
Stenella Coeruleoalba ◽  
The North ◽  
Aegean Islands ◽  
North Aegean ◽  
Diet Analyses ◽  
North Aegean Sea ◽  
Common Dolphins

Cetacean stranding reports in the North Aegean Sea were recorded since 1998 from Strimonikos Gulf in Chalkidiki up to Alexandroupoli on the Turkish border and in a few northern Aegean islands. On site, the specimens were examined to identify species, gender, approximate age and, when possible, cause for stranding. A total of 26 filled stomachs of five cetacean species collected since 2002 were analysed: bottlenose dolphinsTursiops truncatus(N = 8), common dolphinsDelphinus delphis(N = 8), harbour porpoisesPhocoena phocoena(N = 5), striped dolphinsStenella coeruleoalba(N = 4) and Risso's dolphinsGrampus griseus(N = 1). From the analysed stomachs it was found that the bottlenose dolphins fed mainly on snake blennyOphidion barbatum(34%), bogueBoops boops(22%) and round sardinellaSardinella aurita(13%); common dolphins on round sardinella (17%), picarelsSpicaraspp. (10%) and Cocco's lantern fishLobianchia gemellaris(9%); harbour porpoises on Gobidae (four-spotted gobyDeltentosteus quadrimaculatus41% and black gobyGobius niger37%) and round sardinella (7%); striped dolphins on Myctophydae (Madeira lantern fishCeratoscopelus maderensis51%), and on Pfeffer's enople squidAbraliopsis morisii(10%) and bogue (8%); and Risso's dolphin exclusively on Teuthidae (31%), the umbrella squidHistioteuthis bonellii(30%) and the reverse jewel squidH. reversa(14%). The present work represents the first attempt to investigate the diet up to species level for several cetaceans in Greek waters and for harbour porpoises stranded in the Mediterranean Sea.

scholarly journals Cetacean mortality due to interactions with fisheries and marine litter ingestion in the Croatian part of the Adriatic Sea from 1990 to 2019

2021 ◽  
Vol 91 (2) ◽  
pp. 189-206
Author(s):  
Martina Đuras ◽  
◽  
Ana Galov ◽  
Kim Korpes ◽  
Magdalena Kolenc ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Bottlenose Dolphins ◽  
Surveillance Program ◽  
Cetacean Species ◽  
Term Survival ◽  
Stenella Coeruleoalba ◽  
Marine Litter ◽  
Surveillance Programs ◽  
Fisheries Interactions

Various anthropogenic threats negatively influence the survival of cetaceans in all world seas. Thanks to a long-running marine mammal surveillance program, we are able to report the results of a detailed analysis of the influence of cetacean-fisheries interactions and marine litter ingestion on cetacean mortality in the Croatian part of the Adriatic Sea over the last three decades. The total number of dead cetaceans was 459, and included 334 bottlenose dolphins (Tursiops truncatus), 40 striped dolphins (Stenella coeruleoalba), ten Risso’s dolphins (Grampus griseus), six Cuvier’s beaked whales (Ziphius cavirostris) and four fin whales (Balaenoptera physalus). Three hundred of them were examined postmortally. Cetacean-fisheries interaction occurred frequently in the Adriatic Sea, being detected in 96 (20.9%) of the recorded cases. Bycatch was the most abundant cetacean-fisheries interaction, with 66 (14.4%) cases recorded. Good nutritional condition and evidence of recent feeding were the most common findings recorded in bycatch cases, followed by persistent froth in the airways, edematous lungs, bruises and an amputated fluke or tail. Cetacean-fisheries interactions other than bycatch affected 30 animals and included larynx strangulations, long-term tail entanglement and fishing gear in the stomach. Ingestion of marine litter that was not related to fisheries was recorded in four animals. This study reveals the considerable negative anthropogenic influence on cetaceans in the Adriatic Sea, especially the bottlenose dolphin that is considered to be the most numerous cetacean species therein, and demonstrates the need for the urgent development of a cetacean bycatch reduction program. Finally, it also shows the importance of sustaining national surveillance programs to gain scientifically based knowledge important for cetacean protection and prospects for their long-term survival.

Behavioural changes and potential consequences of cetacean exposure to purse seine vessels in the Istanbul Strait, Turkey

2020 ◽  
Vol 100 (5) ◽  
pp. 847-856
Author(s):  
Cristóbal Olaya Meza ◽  
Aylin Akkaya ◽  
Flavio Affinito ◽  
Bayram Öztürk ◽  
Ayaka Amaha Öztürk
Keyword(s):  
Bottlenose Dolphins ◽  
Purse Seine ◽  
Traffic Density ◽  
Long Term Effects ◽  
Cetacean Species ◽  
Behavioural Changes ◽  
Fishing Vessels ◽  
Marine Traffic ◽  
Common Dolphins

AbstractMarine traffic has both short- and long-term effects on cetacean behaviour, yet fishing vessels present a unique situation as they disturb cetaceans whilst potentially offering alternative foraging opportunities. The Istanbul Strait is a key area for the study of anthropogenic disturbance on cetaceans due to heavy human pressure in a narrow space where at least three cetacean species are regularly encountered. The present study investigated changes in behaviour of bottlenose dolphins, common dolphins and harbour porpoises in relation to the presence of purse seiners using Markov chains analysis. The results revealed increased foraging in bottlenose and common dolphins' behavioural budgets and a decrease in the time spent foraging by harbour porpoises. Moreover, a loglinear model was used to analyse the effect of possible confounding variables on observed behaviours. The only variables found to be affecting behaviour were the previous recorded behaviour, seiner presence and marine traffic density. Consequently, the presence of purse seine vessels leads bottlenose and common dolphins to change their behaviour and are related with a decrease of energy intake in porpoises. The results of this study reveal that there is an effect of purse seine vessel presence on the cetaceans found in the Istanbul Strait with potentially significant impacts on their behaviour, therefore we suggest more research is needed in the area to identify the long-term impacts of these observed behavioural changes.

Marine megavertebrates of Cornwall and the Isles of Scilly: relative abundance and distribution

2011 ◽  
Vol 92 (8) ◽  
pp. 1823-1833 ◽  
Author(s):  
Ruth H. Leeney ◽  
Matthew J. Witt ◽  
Annette C. Broderick ◽  
John Buchanan ◽  
Daniel S. Jarvis ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Bottlenose Dolphins ◽  
Marine Biodiversity ◽  
Balaenoptera Acutorostrata ◽  
Delphinus Delphis ◽  
Mola Mola ◽  
Aerial Surveys ◽  
Minke Whales ◽  
Pilot Whales ◽  
Common Dolphins

We document patterns of distribution and relative abundance of marine megavertebrate fauna around Cornwall and the Isles of Scilly from a combination of aerial and boat-based surveying. Between January 2006 and November 2007, 20 aerial surveys were undertaken, comprising over 40 hours of on-effort flying time. In April to October of these years, 27 effort-corrected ferry surveys were also conducted from a passenger ferry travelling between Cornwall and the Isles of Scilly. Opportunistic sightings were also logged by the crew members of the ferry and another vessel travelling regularly along the same route on 155 days. Ten megavertebrate species were sighted: basking sharks Cetorhinus maximus, sunfish Mola mola, common dolphins Delphinus delphis, harbour porpoise Phocoena phocoena, grey seals Halichoerus grypus, Risso's dolphins Grampus griseus, bottlenose dolphins Tursiops truncatus, minke whales Balaenoptera acutorostrata, long-finned pilot whales Globicephala melas and killer whale Orcinus orca. During aerial surveys, 206 sighting events of seven species were made, compared with 145 sighting events of eight species during ferry surveys and 293 sighting events of 10 species from opportunistic ship-board data collection efforts. Seasonal and spatial patterns in species occurrence were evident. Basking sharks were the most commonly-sighted species in the region and were relatively abundant throughout the estimated 5 km-wide strip of coastal waters covered by the aerial surveys, during spring and summer. Ferry surveys and opportunistic vessel-based sightings data confirmed that the distribution of surface-feeding aggregations of this species was largely around the coasts. Despite the limited scope of this study, it has provided valuable baseline data, and possible insights into the marine biodiversity of the region.

Influence of environmental factors on small cetacean distribution in the Spanish Mediterranean

2008 ◽  
Vol 88 (6) ◽  
pp. 1185-1192 ◽  
Author(s):  
A. Gómez de Segura ◽  
P.S. Hammond ◽  
J.A. Raga
Keyword(s):  
Linear Models ◽  
Bottlenose Dolphins ◽  
Chlorophyll Concentration ◽  
Spatial Models ◽  
Distribution Models ◽  
Cetacean Species ◽  
Stenella Coeruleoalba ◽  
Striped Dolphin ◽  
Environmental Features ◽  
Risso's Dolphin

Habitat distribution models are one of the most up to date methods to study the habitat usage of wildlife populations. They allow animal distribution to be related to environmental features and also the prediction of the distribution of animals based on this relationship. Seasonal aerial surveys were conducted in central Spanish Mediterranean waters from June 2000 to March 2003 to obtain information on the distribution of cetacean species. Data from the three most common cetacean species (striped dolphin, Stenella coeruleoalba, bottlenose dolphin, Tursiops truncatus, and Risso's dolphin, Grampus griseus) were related, using generalized linear models, to local environmental features: depth, slope, sea surface temperature and chlorophyll concentration. For bottlenose dolphins, no significant relationship was found with any covariate and no dolphins were observed in waters greater than 1000 m. The distribution of both striped and Risso's dolphin was significantly related to depth. The striped dolphin showed a preference for waters between 900 and 1500 m deep and Risso's dolphin for waters more than 1500 m deep. In addition, for the latest two species, maps of distribution were predicted by means of the spatial models. The areas of higher probabilities of occurrence coincide to a large extent with the marine protected areas previously proposed for the conservation of oceanic cetacean species.

scholarly journals Habitat preferences among three top predators inhabiting a degraded ecosystem, the Black Sea

2017 ◽  
Vol 81 (2) ◽  
pp. 217 ◽  
Author(s):  
Alicia Sánchez-Cabanes ◽  
Maja Nimak-Wood ◽  
Nicola Harris ◽  
Renaud De Stephanis
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Black Sea ◽  
Bottlenose Dolphins ◽  
Habitat Preferences ◽  
Additive Models ◽  
Sea Surface ◽  
The Black Sea ◽  
Cetacean Species ◽  
Common Dolphins

This study investigated whether there is evidence of widespread niche partitioning based on environmental factors in the Black Sea and tested the hypothesis that physiographic factors may be employed as predictors. It addresses poorly researched areas with good habitat potential for the only three cetacean subspecies living in this area: the Black Sea short-beaked common dolphin (Delphinus delphis spp. ponticus), the Black Sea bottlenose dolphin (Tursiops truncatus spp. ponticus) and the Black Sea harbour porpoise (Phocoena phocoena spp. relicta). Generalized additive models (GAMs) were used to analyse data collected from multiple sources. In total, 745 sightings of the three species between 1998 and 2010 throughout the Black Sea were included. The analysis found depth and sea surface temperature to be the most important variables for separating the occurrence of the three species. Common dolphins occurred mainly in deep waters and in areas where the sea surface temperature was low, bottlenose dolphins were distributed primarily in shallower and warmer waters than common dolphins, and harbour porpoises were distributed in shallower waters with lower sea surface temperature than bottlenose dolphins. This study suggests strong niche segregation among the three cetacean species. The study is also the first contribution to the basic information of cetacean species distribution and habitat preferences in the Black Sea as a whole. Knowledge of the distribution of the three dolphin species in the study area is essential to establish conservation measures for these populations.

scholarly journals Causes of cetacean stranding and death on the Catalonian coast (western Mediterranean Sea), 2012-2019

2020 ◽  
Vol 142 ◽  
pp. 239-253
Author(s):  
M Cuvertoret-Sanz ◽  
C López-Figueroa ◽  
A O’Byrne ◽  
A Canturri ◽  
B Martí-Garcia ◽  
...  
Keyword(s):  
Cause Of Death ◽  
Maternal Separation ◽  
Systemic Disease ◽  
Bottlenose Dolphins ◽  
Unknown Origin ◽  
Western Mediterranean ◽  
Common Dolphin ◽  
Stenella Coeruleoalba ◽  
Fin Whale ◽  
Catalan Coast

The causes of cetacean stranding and death along the Catalan coast between 2012 and 2019 were systematically investigated. Necropsies and detailed pathological investigations were performed on 89 well-preserved stranded cetaceans, including 72 striped dolphins Stenella coeruleoalba, 9 Risso’s dolphins Grampus griseus, 5 bottlenose dolphins Tursiops truncatus, 1 common dolphin Delphinus delphis, 1 Cuvier’s beaked whale Ziphius cavirostris and 1 fin whale Balaenoptera physalus. The cause of death was determined for 89.9% of the stranded cetaceans. Fisheries interaction was the most frequent cause of death in striped dolphins (27.8%) and bottlenose dolphins (60%). Cetacean morbillivirus (CeMV) was detected on the Catalan coast from 2016 to 2017, causing systemic disease and death in 8 of the 72 (11.1%) striped dolphins. Chronic CeMV infection of the central nervous system was observed from 2018-2019 in a further 5 striped dolphins. Thus, acute and chronic CeMV disease caused mortality in 18% of striped dolphins and 14.6% of all 89 cetaceans. Brucella ceti was isolated in 6 striped dolphins and 1 bottlenose dolphin with typical brucellosis lesions and in 1 striped dolphin with systemic CeMV. Sinusitis due to severe infestation by the nematode parasite Crassicauda grampicola caused the death of 4 out of 6 adult Risso’s dolphins. Maternal separation, in some cases complicated with septicemia, was a frequent cause of death in 13 of 14 calves. Other less common causes of death were encephalomalacia of unknown origin, septicemia, peritonitis due to gastric perforation by parasites and hepatitis caused by Sarcocystis spp.

Distribution of Pholeter gastrophilus (Digenea) within the stomach of four odontocete species: the role of the diet and digestive physiology of hosts

Parasitology ◽  
2006 ◽  
Vol 133 (3) ◽  
pp. 369-380 ◽  
Author(s):  
F. J. AZNAR ◽  
P. FOGNANI ◽  
J. A. BALBUENA ◽  
M. PIETROBELLI ◽  
J. A. RAGA
Keyword(s):  
Host Species ◽  
Size Structure ◽  
Energy Content ◽  
Bottlenose Dolphins ◽  
Caloric Content ◽  
Digestive Physiology ◽  
Food Passage ◽  
Stenella Coeruleoalba ◽  
Pilot Whales ◽  
Chamber Size

We compared the distribution of the digenean Pholeter gastrophilus in the stomach of 27 harbour porpoises, Phocoena phocoena, 27 striped dolphins, Stenella coeruleoalba, 18 bottlenose dolphins, Tursiops truncatus, and 100 long-finned pilot whales, Globicephala melas. The stomach of these species is composed of 4 chambers of different size, structure and function. In all species, P. gastrophilus was largely restricted to the glandular region of the stomach, but the parasite tended to favour the fundic chamber in bottlenose dolphins and harbour porpoises, the pyloric chamber in pilot whales, and none in striped dolphins. However, predictability at infrapopulation level was generally low, suggesting a weak preference of P. gastrophilus for any of the chambers. Three hypotheses were tested to investigate a common cause for the distribution of P. gastrophilus in all host species, namely, colonization of chambers was (1) sequential, (2) dependent on chamber size, or (3) dependent on the passage time of food through the whole stomach. The latter hypothesis was indirectly tested by assuming, based on previous evidence from other vertebrates, that the greater the size of the stomach and/or the energy content of prey, the greater the delay of food passage. We found no compelling evidence that chamber colonization was sequential, or related to chamber size in any species. However, the distribution of P. gastrophilus was significantly more anteriad when the host species had larger stomachs and, particularly, when hosts fed on prey with higher caloric content. Accordingly, the stomach distribution of P. gastrophilus at this scale seems to be passively driven by features of the diet and digestive physiology of each host species. This study provides a general framework to formulate null hypotheses in future studies on microhabitat choice by parasites.

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