Scientific Literature: Searchable Database

Through a co-operation between the NGO MEER and local whale watching operators on the island of La Gomera (Canary Islands, Spain) a long-term sighting data scheme was initiated in 1995 which lasts until today. During 15 years (from September 1995 until October 2010) a total of more than 6,000 sightings of up to 23 cetacean species have been documented at low cost in a pioneering way, establishing previously unknown detailed knowledge about the local cetacean fauna. As of today, this collection represents one of the few data sets where cetacean abundance and distribution has been monitored throughout the year for almost one and a half decades. Here, we describe inter-annual changeability and long-term trends of abundance in several species inhabiting the same general area. Long-term trends in abundance were found, with some species showing significantly declining sighting numbers. Because cetaceans are known to react with great flexibility to changes in their habitat, these findings reflect the dynamic nature of the environment itself, but they also could be related to climate change effects. Cetaceans can thus function as indicators for environmental changes. The relation between cetacean abundance and the ecological conditions of the sea around them is laid out.