An individual-based model to infer the impact of whalewatching on cetacean population dynamics

Lusseau, D., Lusseau, S.M., Bejder, L. and Williams, R. (2006) An individual-based model to infer the impact of whalewatching on cetacean population dynamics. Scientific Committee of the International Whaling Commission

Abstract

Whalewatching play an important socioeconomic role in many countries. Yet after 20 years of research in its effects on the targeted populations, its sustainability is now questioned. While much progress has been made to understand the short-term influences of boat-cetacean interactions for individuals and schools, the long-term consequences of those remain uncertain. Recent studies showed that the stress related to both interactions themselves and the avoidance strategies individuals used can affect the fitness of individuals and their reproductive success. The decrease in individual fitness can itself result in lowered survival probabilities, because of increases in either mortality or emigration rates. We introduce an individual-based model of population dynamics which attempt to incorporate these findings to understand their potential consequences for the dynamics of populations. This model is based on realistic scenarios in which schools of individuals are exposed to boat interactions on a daily basis. This results in different yearly cumulative exposure to boat for each individual. The relationship between survival and reproductive parameters are then linked for each individual to their boat exposure using logistic functions. Variance is introduced in these functions to highlight both the uncertainty in the relationships as well as individual variation in effect size. Using two case studies we show that whalewatching can influence the dynamics of cetacean populations and can also jeopardise the viability of populations which are already at risk.

Item Type:	Report
Murdoch Affiliation(s):	Centre for Fish and Fisheries Research
Series Name:	SC/58/WW7
Publisher:	Scientific Committee of the International Whaling Commission
URI:	http://researchrepository.murdoch.edu.au/id/eprint/21850

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