Are epizoites biological indicators of a western Mediterranean striped dolphin die-off?

Abstract

During a die-off of Mediterranean striped dolphins Stenella coeruleoalba in 1990-91, 82 individuals stranded on the Spanish coast were examined for crustacean ectoparasites and epizoites. Six species were detected: Syncyarnus aequus, PenneUa sp., Xenobalanus globicipitis, Conchoderma virgatum, Lepas pectinata and Lepas cf. hillii. The barnacles L. pectinata and L. cf. hillii are reported here for the first time on cetaceans; they were attached to the teeth. C. virgaturn was also found on the teeth; this is an unusual attachment on cetaceans. X. globicipitis showed a higher prevalence on the dolphins studied than on those stranded in the same months before (1980 to 1990) and after (1991 to 1993) the epizootic. An analysis of shell and pseudocapitulum sizes of the X. globicipitis infrapopulations indicated possible recent colonization. It is suggested that settlement of some epizoites might have increased due to reduced movement of the dolphins and/or impaired regenerative and immune functioning of the skin prior to death. This might account for the exceptional occurrence of Lepas spp. attached on the teeth, the unusual attachment of C. virgatum, and the higher prevalence and apparently young infrapopulations of X. globicipitis.

Epibiotic macrofauna on common minke whales, Balaenoptera acutorostrata Lacépède, 1804, in Icelandic waters

“…Spatial differences in the prevalence of X. globicipitis on Antarctic minke whales examined in summer, suggests that these whales also have separate winter grounds where the exposure to the barnacle is different [14]. A study on Mediterranean striped dolphins, Stenella coeruleoalba (Meyen, 1833), concluded that an increased prevalence of X. globicipitis on certain individuals was due a viral epizootic in the population predisposing individuals to infection [16,52]. Previous records of the species from Greenland and Finnmark in northern Norway [47] together with the present study probably represent the northern limits of their distribution in the North Atlantic.…”

Patologia comparada de cetáceos e pinípedes

“…Grandes cargas parasitárias são comuns. Os odontocetos afetados apresentam muitos ectoparasitas e comensais aderidos à pele, além de grande perda de peso (AZNAR et al, 1994;DOMINGO et al, 1992;DUIGNAN et al, 1992). Estomatites e gengivites ulcerativas agudas ou crônicas podem estar presentes.…”

“…As alterações encontradas sugerem que este indivíduo sofresse de um processo crônico, tornando-o debilitado e vulnerável . Aznar et al, (1994) discutem que a diminuição da movimentação de um cetáceo doente e a redução das capacidades regenerativa e imune da pele favorecem a colonização por crustáceos. No presente estudo, os crustáceos encontrados eram adultos.…”

Macroscopic Lesions on the Grey Triggerfish, Balistes Capriscus (Pisces) Associated with the Presence of the Pedunculate Barnacle, Conchoderma Virgatum (Cirripedia, Thoracica)

“…Direct attachment of C. virgatum on fish has been recorded on a few species, namely on hard substratum (e.g., spines; dentary region; jaw; gill arch; bill of a swordfish) (Crozier, 1916;Beckett, 1968;Jones et al, 1968;Balakrishnan, 1969;Hastings, 1972;Aznar et al, 1994;Williams & Bunkley-Williams, 1996). Besides hard structures, direct settlement on the integral skin of fishes is rare and often associated with previous injuries or infections by parasitic copepods (Jones et al, 1968).…”