Social Structure of False Killer Whales in Maui Four-Island Region

Project Name:

Social Structure of False Killer Whales (Pseudorca crassidens) in Maui Four-Island Region 

Study System:

False killer whales (Pseudorca crassidens) – Endangered (insular population)

Motivation and Goals:

There are two populations of false killer whales in Hawaiian waters: an offshore population and an insular (island-associated) population.  Both populations have experienced a decline due to multiple threats including fisheries interactions, ingestion of marine debris, and exposure to anthropogenic noise pollution.   Due in large part to these threats, the insular population has recently been listed under the Endangered Species Act.

The social ecology and behavior of false killer whales is poorly understood. This research project is focused on using photo-identification to increase our knowledge, allowing us to better manage and conserve this species. 

Methods:

The survey methodology for this project closely follows that for the research project titled “Odontocete distribution, abundance, and life-histories”.

Using line transect surveys, we search for pods of false killer whales. Once a pod has been sighted, we leave the transect line to gather detailed behavioral observations of the pod for a length of time up to 60 minutes. During this time we also take identification photos of the dorsal fins and sides of the animals. 

These photos allow us to build a photo-identification catalog for false killer whales to estimate the number of individuals and examine how those animals move at large and small scales within their habitat.  

Results to Date:

Our photo-identification catalog currently contains over 80 individuals dating back to 1996. 

The catalog is also used to maintain a history of sightings for all of our false killer whales available for adoption. 

Next Steps:

The research department will continue this study through 2018 and continue to build upon the existing photo-identification catalog.  

Most Recent Publication:

2013: Silva, I.F., Kaufman, G.D., Rankin, R.W., and Maldini, D. Presence and Distribution of Hawaiian False Killer Whales (Pseudorca crassidens) in Maui County Waters: an Historical Perspective. Aquatic Mammals, 39(4): 409-414.