Variations in cetaceans stranding number are related to population consistency and/or to stressful factor which can act on populations. Age-dependent variations are usually considered as a marker of the presence of specific stress factors of pathogenic, toxicological or antropogenic origin. Seasonal-dependent variation are connected to use of habitat or movement of populations. Striped dolphin is widely diffused and abundant in Mediterranean Sea and has proved to be highly sensitive to infectious factor, e.g. Morbillivirus epidemics in the 90s, and contaminants. In the last three years stranding data collected at Centro Recupero Fauna Selvatica e Tartarughe Marine of Comiso, Sicily, seemed to underline an increase in the number of death young striped dolphins and the aim of the paper is to verify if there is any significant difference in years. Data collected directly in the centre from 2005 till September 2008 were compared with those available in Italian Stranding Database (http://www-1.unipv.it/cibra/spiaggiamenti.html) concerning Sicily from 1986 till 2004. From the two databases a 1.5 m length was retained as threshold to discriminate between adults and juveniles and the number per year were converted as relative percent values. Obtained data seems to confirm starting hypothesis as while during the period 1986-2004 mean number of young stranded dolphins was smaller than that of adult (4.6/year vs. 7.8/year respectively), from 2005 till 2008 an opposite trend was observed (9.75/year vs.3.25/year). Excluding the great number of stranding observed in 1991 due to the Morbillivirus infection, affecting adults in particular, did not change results. Strandings are concentrated in the period from May to September with no significant variations between years. From collected data there seems to be a real changing in the age-dependent number of stranding and a special effort is prepared to verify next year the possible reason of such a large number of death animals.

Age- and seasonal-dependent numerical variations of stranded striped dolphin (Stenella coeruleoalba) in Sicily

ZACCARONI, ANNALISA;SCARAVELLI, DINO
2009

Abstract

Variations in cetaceans stranding number are related to population consistency and/or to stressful factor which can act on populations. Age-dependent variations are usually considered as a marker of the presence of specific stress factors of pathogenic, toxicological or antropogenic origin. Seasonal-dependent variation are connected to use of habitat or movement of populations. Striped dolphin is widely diffused and abundant in Mediterranean Sea and has proved to be highly sensitive to infectious factor, e.g. Morbillivirus epidemics in the 90s, and contaminants. In the last three years stranding data collected at Centro Recupero Fauna Selvatica e Tartarughe Marine of Comiso, Sicily, seemed to underline an increase in the number of death young striped dolphins and the aim of the paper is to verify if there is any significant difference in years. Data collected directly in the centre from 2005 till September 2008 were compared with those available in Italian Stranding Database (http://www-1.unipv.it/cibra/spiaggiamenti.html) concerning Sicily from 1986 till 2004. From the two databases a 1.5 m length was retained as threshold to discriminate between adults and juveniles and the number per year were converted as relative percent values. Obtained data seems to confirm starting hypothesis as while during the period 1986-2004 mean number of young stranded dolphins was smaller than that of adult (4.6/year vs. 7.8/year respectively), from 2005 till 2008 an opposite trend was observed (9.75/year vs.3.25/year). Excluding the great number of stranding observed in 1991 due to the Morbillivirus infection, affecting adults in particular, did not change results. Strandings are concentrated in the period from May to September with no significant variations between years. From collected data there seems to be a real changing in the age-dependent number of stranding and a special effort is prepared to verify next year the possible reason of such a large number of death animals.
Abstracts of 23rd Annual Conference of the European Cetaceans Society.
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Insacco G.; Zaccaroni A.; Scaravelli D.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/92067
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