Analysis of the presence of fin whale (B. physalus), sperm whale (P. macrocephalus) and Cuvier’s beaked whale (Z. cavirostris) in the Gulf of Genoa: is anything changing?

Abstract

Since 2007, Fondazione Acquario di Genova, in collaboration with Golfo Paradiso Whale Watching, has been carried out a research activity on cetacean presence and distribution in the Pelagos area off the coast of Genova. The aim of this study is to analyze the presence and distribution of fin whale, sperm whale and Cuvier’s beaked whale in 2023, comparing the results with the time series from 2007 to 2022. Data were collected from May to October 2023 during daily surveys on board the whale watching boats. Four principal components were analysed: sampling effort, distribution of sightings, encounter rate (ER=number of sightings/km of effort) and the concentration of chlorophyll-a (Chl-a, mg/m3) in surface waters. Among the results obtained sightings of fin whale recorded in 2023 were far more numerous than those recorded in previous sampling years and Chl-a concentration in the study area was lower in 2023 compared to previous years (2010-2022).