Gastrointestinal helminths of Risso's dolphin Grampus griseus from the Western Mediterranean

Fernández, Mercedes; Agusti, Celia; Aznar, Francisco Javier; Raga, Juan Antonio

doi:10.3354/dao055073

Cited by 18 publications

(10 citation statements)

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“…In the Mediterranean Sea, it has been reported to be a common intestinal parasite of G. melas and G. griseus (Raga and Balbuena , Fernández et al . ). Accordingly, this study reports for the first time, T. globicephalae infecting a species from the genus Stenella .…”

Section: Discussionmentioning

confidence: 97%

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Intestinal helminth fauna of striped dolphins (Stenella coeruleoalba) in the western Mediterranean: No effects of host body length, age and sex

Mateu

Raga

Fernández

et al. 2014

Marine Mammal Science

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The intestine of 52 (28 males and 24 females) striped dolphins (Stenella coeruleoalba) from western Mediterranean waters was examined for helminths. Animals were found stranded along the Spanish coasts during the morbillivirus epizootic in 1990. In accordance with observations from other pelagic tetrapods, including cetaceans from other geographical regions, the intestinal helminth community was depauperate. Four helminth species were found: three tetrabothriid cestodes, Tetrabothrius forsteri (prevalence: 96.2%; mean intensity [95% CI]: 47.4 [34.4-68.2]), Trigonocotyle globicephalae (9.6%; 1.8 [1.0-2.2]), and Strobilocephalus triangularis (23.1%; 5.3 [2.9-10.2]), and immature individuals of the acanthocephalan Bolbosoma vasculosum (51.9%; 2.7 [2.0-3.4]). Schluter's variance test indicated a weak, but statistically significant association of occurrence of helminth species in dolphins, suggesting that some tetrabothriid species might use the same intermediate or paratenic hosts. Neither the abundance of helminth species nor infracommunity descriptors were significantly affected by sex, host body length or age. The absence of predictable effects of body size and age on the recruitment rate of helminths could be related to the fact that the host sample was largely composed of adults. This study provides quantitative evidence about helminth community structure of striped dolphins, based on a large sample size.

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Section: Discussionmentioning

confidence: 97%

“…; Fernández et al . , ). In other words, oceanic cetaceans behave as an isolated group for exchange of parasites, if at all (Aznar et al .…”

Section: Discussionmentioning

confidence: 99%

Intestinal helminth fauna of striped dolphins (Stenella coeruleoalba) in the western Mediterranean: No effects of host body length, age and sex

Mateu

Raga

Fernández

et al. 2014

Marine Mammal Science

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“…(found in or on a few animals dead-and live-stranded in Spain and Italy; Cornaglia et al, 2000;Domingo et al, 2000;Resendes et al, 2002;Zucca et al, 2004Zucca et al, , 2005Marcer et al, 2008). Also, Fernández et al (2003) reported 5 species of gastrointestinal helminths found in 17 Risso's dolphins stranded in the western Mediterranean.…”

Section: Parasites and Epizooticsmentioning

confidence: 96%

Risso's dolphin Grampus griseus in the Mediterranean Sea

Bearzi

Reeves²,

Remonato

et al. 2011

Mammalian Biology

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a b s t r a c tThe ecology and status of Risso's dolphins Grampus griseus worldwide are poorly known. In the Mediterranean Sea, modern field studies of cetaceans only began in the late 1980s and this has resulted in rapid advances in knowledge of some species, but not Risso's dolphin. This paper reviews available information on the distribution and ecology of Risso's dolphins in the Mediterranean and identifies factors that may negatively affect them in this region. Risso's dolphins occur in continental slope waters throughout the Mediterranean basin and around many of the region's offshore islands and archipelagos. No synoptic estimate of abundance is available for the Mediterranean region, but densities and overall numbers are low in comparison to some other small odontocetes. Diet consists primarily of cephalopods, with a clear preference for mesopelagic squid. The principal known threat to populations in the Mediterranean is entanglement in pelagic drift gillnets. Other potential problems for Risso's dolphins in the Mediterranean include noise disturbance and ingestion of plastic debris. Conservation actions to mitigate the risk of entanglement in fishing gear are likely to benefit Risso's dolphins; specifically, the existing driftnet ban in EU waters should be strictly enforced and extended to the high seas and to waters under non-EU State jurisdiction. More and better data are needed on abundance, distribution, movements, population dynamics and trends in Risso's dolphin populations, and better information on threats (e.g. bycatch in fishing gear) is needed to inform conservation efforts.

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“…Thus, it is puzzling how P. gastrophilus is able to infect a sizeable proportion of two dolphin species with such a small overlap in habitat and diet. The problem is compounded because, in the study area, this parasite also infects other oceanic cetaceans that feed almost exclusively on mesopelagic cephalopods [ 28 , 29 ]. Unfortunately, parasitological surveys have failed to find infective stages of P. gastrophilus in the main prey of striped and bottlenose dolphins, see [ 62 , 63 ].…”

Section: Discussionmentioning

confidence: 99%

Life-history trade-offs in a generalist digenean from cetaceans: the role of host specificity and environmental factors

et al. 2015

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BackgroundAdults and larvae of generalist parasites are exposed to diverse hosts and local environmental conditions throughout their life cycles, thus local adaptation is expected to occur through phenotypic plasticity and/or natural selection. We investigated how the combined effect of cryptic host specificity and local selective pressures could shape reproductive traits of a putative generalist parasite in the oceanic realm.MethodsThe LSU rDNA, ITS2 and the mt-COI of individuals of the digenean Pholeter gastrophilus (Kossack, 1910) Odhner, 1914 (Heterophyidae Leiper, 1909) from oceanic striped dolphins, Stenella coeruleoalba Meyen, and coastal bottlenose dolphins, Tursiops truncatus Montagu, in the western Mediterranean were used to elucidate whether worms were conspecific. Infection parameters were compared between both dolphin species. General Linear Mixed Models were used to analyse the influence of host species on four reproductive traits of P. gastrophilus: body size, maturity stage (non-gravid/gravid), egg size, and number of eggs in utero. AIC values were used to rank competing models, and p-values to assess the effect of specific predictors.ResultsEvidence indicated that worms collected from both dolphin species were conspecific. All worms collected were gravid and infection parameters did not differ between dolphin species. However, body size and egg size of individuals of P. gastrophilus were significantly larger in striped dolphins. The number of eggs in utero did not significantly differ between dolphin species but, for a given body size, worms in bottlenose dolphins harboured more eggs. A trade-off between egg size and egg number was found in worms from both dolphin species, with a higher slope in striped dolphins.ConclusionsApparently, striped dolphin is a more suitable host for P. gastrophilus, but reproductive investment seems to be adapted to the habitat where the life-cycle develops. Worms from striped dolphins likely face the problem of finding intermediate hosts in the oceanic realm and apparently invest into offspring size to enhance the early survival of larvae and the potential to multiply asexually within the first intermediate host. The small-sized worms from bottlenose dolphins would be adapted to reproduce early because of higher adult mortality, generating smaller and numerous eggs in a coastal habitat where chances of transmission are presumably higher.

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Gastrointestinal helminths of Risso's dolphin Grampus griseus from the Western Mediterranean

Cited by 18 publications

References 10 publications

Intestinal helminth fauna of striped dolphins (Stenella coeruleoalba) in the western Mediterranean: No effects of host body length, age and sex

Intestinal helminth fauna of striped dolphins (Stenella coeruleoalba) in the western Mediterranean: No effects of host body length, age and sex

Risso's dolphin Grampus griseus in the Mediterranean Sea

Life-history trade-offs in a generalist digenean from cetaceans: the role of host specificity and environmental factors

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