Scientists use many different methods to study whales and dolphins in the wild. Below is a brief summary of the most common methods used with a few illustrations. Of these, only a few are easily combined with whale watching, but managers, tour operators and whale watchers alike may be interested to learn more about how researchers learn about whales and dolphins and their conservation needs.
Boat surveys to study distribution and habitat use: Meticulously recording the whale and dolphin observations that are made during vessel-based surveys in a particular study area can provide insight into which species are present and at which time of year. Sightings can be recorded in a non-systematic manner, as is often the case when sightings are recorded from whale watching vessels, or studies can be carried out more systematically, with planned transects that provide even coverage of the target area. A more systematic approach allows researchers to draw conclusions about where the whales or dolphins are NOT present as well as where they are present. Only through such a systematic approach can robust conclusions be drawn about the animals’ preferred habitats.
One of the most commonly used research methods, particularly in areas where little is known about the species or whales or dolphins that are present, or their population numbers is the Line transect method. Researchers define their study area (often a bay, or a strip of coastal waters) and design a method to cover that area as systematically as possible with evenly spaced parallel transects or zig-zags. They then use a research vessel to navigate these transect lines and record all of the whales and dolphins that they observe as they go along. By comparing encounter rates (e.g. how many whales are observed per kilometre or per hour searched) in different seasons or in parts of the study area, researchers can also understand whether there are seasonal patterns to the animals’ distributions, or whether certain species prefer shallow or deep habitats, rocky or sandy bottomed areas, rivermouths or open water, etc. This data can be used to help managers decide where to conduct dolphin watching activities, where to create marine protected areas for whales and dolphins, and where environmental impact assessments for marine or coastal activities need to take whales and dolphins into account. Data from dolphin watching vessels can be used to perform similar analysis if the vessels are also able to supply information on their daily tracks or search effort, as well as their sightings. But whale-watching tracks are likely to be biased toward the known ‘hotspots’ for whales2. Line transect methods can also be used to generate abundance estimates (see below for more detail).