Sighting surveys are the standard scientific method of estimating the abundance of many species of wildlife. The cetacean surveys in the LAPE all used transect methods, by which a survey vessel steams along a pre-selected track while a team of observers and recorders scan the vicinity for cetaceans. When a sighting is made the vessel diverts to collect additional information such as species identification, estimating the number of animals (pod size), looking for the presence of calves and also taking photographs.
Sighting surveys are dependent on sea and weather conditions. Primary sightings are those collected when the conditions are better than specified standards (minimum visibility of 3 n. mi. and maximum of Beaufort Force 4 winds in large-scale surveys and Force 3 in small-scale surveys). Only information collected during primary sighting conditions is usually used for statistical abundance estimation as poor sighting conditions introduce obvious biases in the ability of observers to see the cetaceans.
The large-scale surveys were both conducted from large research ships over approximately 4 weeks at sea, in 2004 and 2006.
Small-scale surveys were conducted in 2004 and 2005 under the LAPE project. These data were amalgamated with data from 2000 to 2003 for surveys previously conducted by some of the countries in the area. Small-scale surveys were usually conducted from sport fishing boats in a series of four to seven day trips.