March 12, 2012 - This web page contains information about the individual-based modeling project, "Agent-Based Models of Predator-Prey Relationships between Killer Whales and Other Marine Mammals". Through an agent-based model using Repast we are studying the impact of killer whales on several threatened marine mammal species, including Steller sea lions and sea otters in Alaska. This work has been made possible by a grant from the Marine Mammal Commission.

The role of killer whales in the decline of various marine mammal populations in Alaska is controversial and potentially important. Estimation of killer whale numbers and the rates of predation on various marine mammal species now have high research priority, but how we interpret these new data is dependent on having an adequate theoretical framework. Thus far, only simplistic, static models of killer whale consumption have been constructed to test the plausibility of killer whale impact on other species. This is partly because the interactions between transient killer whales and their marine mammal prey are poorly suited to classical, Lotka-Volterra approaches to modeling predator-prey systems. Agent-based models simulate the biology and behavior of single agents that interact to produce emergent properties of the larger system. This killer whale model is an agent-based model at two levels: the level of individual transient (mammal eating) killer whales that eat, grow, reproduce, and ultimately die, and the level of hunting groups that can change in size and composition while encountering and killing other marine mammals. The prey, on the other hand, are modeled at the population level where only their density determines how often they are encountered by groups of killers whales.

For more information, read our final report: word, pdf.


J. Ward Testa, Biological Sciences, National Marine Mammal Laboratory
Kenrick Mock, Computer Science, University of Alaska Anchorage


Cameron Taylor, undergraduate, Computer Science
Russell Waggoner, undergraduate, Computer Science
Heather Koyuk, undergraduate, Computer Science
Jessica Coyle, undergraduate, Biology / Math