6533b838fe1ef96bd12a4698

RESEARCH PRODUCT

Boat traffic in Lampedusa waters (Strait of Sicily, Mediterranean Sea) and its relation to the coastal distribution of common bottlenose dolphin (Tursiops truncatus).

subject

description

The volume of boat traffic and its potential connection to the coastal distribution of the common bottlenose dolphin (Tursiops truncatus) was evaluated off Lampedusa Island (Strait of Sicily). From July to September 2006 daily surveys were carried out at eight sites along the coast, three times a day, to assess the number, type, and size of boats moving, fishing, or stationed in Lampedusa waters. The study area was divided into four geographic areas: northwest, northeast, southwest, and southeast. Data were analyzed to determine the difference in the number of boats among the areas, sampling months, and times of day. The presence of dolphins was monitored by standardized land-based observations. Dolphins (n = 139) from 38 sightings were observed throughout the study period (90 days). In order to compare the presence of dolphins among areas, a relative abundance index was used: A-EH (number of sighted specimens per effort hour). Common bottlenose dolphins appeared to be broadly distributed around Lampedusa, although this study highlighted a possible overlap between their habitat, boat traffic, and fishery, especially in the southwest. Se evaluo el volumen de trafico de barcos y su conexion potencial con la distribucion costera del delfin nariz de botella (Tursiops truncatus) en las aguas circundantes a la Isla de Lampedusa (Estrecho de Sicilia). De julio a septiembre de 2006 se llevaron a cabo monitoreos en ocho sitios a lo largo de la costa, tres veces al dia, para determinar el numero, tipo y tamano de barcos moviendose, pescando o estacionarios en las aguas de Lampedusa. La zona de estudio se dividio en cuatro areas geograficas: noroeste, noreste, suroeste y sureste. Los datos se analizaron para determinar la diferencia entre el numero de barcos en las areas estudiadas, meses de muestreo y horarios diurnos. La presencia de delfines se monitoreo mediante observaciones estandardizadas desde tierra. Se observaron delfines (n = 139) de 38 avistamientos a lo largo del periodo de estudio (90 dias). Para comparar la presencia de delfines entre las areas se utilizo un indice de abundancia relativa: A-EH (numero de especimenes observados por hora de esfuerzo). Los delfines nariz de botella parecieron estar ampliamente distribuidos alrededor de Lampedusa, aunque este estudio resalto un posible traslapo entre su habitat, trafico de barcos y pesqueria, especialmente en el suroeste.