Studying dolphins' habitat may help protect them

By Rachel Manuel

As the whale-watching industry in Hawaii grows, so do the human threats to spinner dolphins. Through projects of habitat modeling, researchers hope to find and protect unstudied areas in which dolphins live. This modeling involves looking at the characteristics of dolphins' habitat, then finding areas with similar characteristics that could be other habitats.

Marine debris such as nets and fishing gear pose a great threat to mammals, which could get ensnared in them or choke on them. Photo courtesy of NOAA.

The closeness of boats and swimmers to dolphins could harm their health and affect their behavior. Such disturbances include:

Marine debris also threatens dolphins. Plastic and abandoned fishing gear can be harmful when eaten and could lead to internal injuries, intestinal blockage, starvation and even death. Fishery equipment like hooks, lines, nets and traps could ensnare the mammals. According to the National Marine Fisheries Service, there have been incidents of spinner dolphins becoming entangled in nets.

Habitat modeling

Habitat modeling is one method the CRU uses to collect data, with which to figure out means to protect spinner dolphins. Other methods include passive acoustic monitoring and photo-identification studies. Photo courtesy of Dave Johnston.

To manage the effects of humans on the dolphin population and protect them, the cestacean research unit (CRU) at the Pacific Islands Fisheries Science Center studies the dolphin population within the waters of the Pacific Islands Region, which includes Hawai'i. One research method is habitat modeling.

Habitat modeling is done by observing in-site and through satellites. Dolphin habitats are first located, then by means of ecosystem observation, researchers study the habitat's biogeochemical characteristics. Such features include chemical, physical and geological characteristics and the environment's composition. By using this information, researchers look for other areas with similar features.

The data gathered from habitat modeling can be used to find then protect other resting habitats. This CRU project involves quantifying the characteristics of the observed dolphins' resting habitats by fine-scale physical habitat mapping exercises then comparing regions that are not currently studied. Unobserved resting habitats could then be identified through the detection of similar features at other locations.

Related Links:

• Current research methods by CRU at the Pacific Island Fisheries Science Center
• Photo-identification of spinner dolphins
• Potential threats to spinner dolphins