[MARMAM] Two new papers on the behavioural response of common minke whales to whalewatching activities

Fredrik denupplyste at hotmail.com
Tue Dec 3 22:47:13 PST 2013

I am pleased to announce the publication
of the following two papers focusing on the behavioural response of minke
whales towards whalewatching boats on a feeding ground in Iceland.



Paper 1:


Christiansen, F., Rasmussen, M. & Lusseau, D. 2013.
Whalewatching boats disrupt the foraging activities of Minke whales in Faxaflói
bay, Iceland. Marine Ecology Progress
Series 478: 239-251.



Human disturbances of wildlife,
such as tourism, can alter the activities of targeted individuals. Repeated
behavioural disruptions can have long-term consequences for individual vital
rates (survival and reproduction). To manage these sub-lethal impacts, we need
to understand how activity disruptions can influence bioenergetics and
ultimately individual vital rates. Empirical studies of the mechanistic links
between whale-watching boat exposure and behavioural variation and vital rates
are currently lacking for baleen whales (mysticetes). We compared minke whale Balaenoptera
acutorostrata behaviour on a feeding ground in the presence and absence of
whale-watching boats. Effects on activity states were inferred from changes in
movement metric data as well as the occurrence of surface feeding events.
Linear mixed effects models and generalised estimation equations were used to
investigate the effect of whale-watching boat interactions. Measurement errors
were quantified, and their effects on model parameter estimates were
investigated using resampling methods. Minke whales responded to whale-watching
boats by performing shorter dives and increased sinuous movement. A reduction
in the probability of observing longer inter-breath intervals during sinuous
movement showed that whale-watching boat interactions reduced foraging
activity. Further, the probability of observing surface feeding events also
decreased during interactions with whale-watching boats. This indicates that
whalewatching boats disrupted the feeding activities of minke whales. Since
minke whales are capital breeders, a decrease in feeding success on the feeding
grounds due to whale-watching boats could lead to a decrease in energy
available for foetus development and nursing on the breeding grounds. Such
impact could therefore alter the calving success of this species.




Paper 2:


Christiansen, F., Rasmussen, M. & Lusseau, D. 2013.
Inferring activity budgets in wild animals to estimate the consequences of
disturbances: Effects of whalewatching boat interactions on minke whales. Behavioural
Ecology 24(6): 1415-1425. doi: 10.1093/beheco/art086



Activity budgets can provide a
direct link to an animal’s bioenergetic budget and is thus a valuable unit of
measure when assessing human induced nonlethal effects on wildlife conservation
status. However, activity budget inference can be challenging for species that
are difficult to observe and require multiple observational variables. Here, we
assessed whether whalewatching boat interactions could affect the activity
budgets of minke whales (Balaenoptera acutorostrata). We used a stepwise
modeling approach to quantitatively record, identify, and assign activity
states to continuous behavioral time series data, to estimate activity budgets.
First, we used multiple behavioral variables, recorded from continuous visual
observations of individual animals, to quantitatively identify and define
behavioral types. Activity states were then assigned to each sampling unit,
using a combination of hidden and observed states. Three activity states were
identified: nonfeeding, foraging, and surface feeding (SF). From the resulting
time series of activity states, transition probability matrices were estimated using
first-order Markov chains. We then simulated time series of activity states,
using Monte Carlo methods based on the transition probability matrices, to
obtain activity budgets, accounting for heterogeneity in state duration.
Whalewatching interactions reduced the time whales spend foraging and SF,
potentially resulting in an overall decrease in energy intake of 42%. This modeling
approach thus provides a means to link short-term behavioral changes resulting
from human disturbance to potential long-term bioenergetic consequences in
animals. It also provides an analytical framework applicable to other species
when direct observations of activity states are not possible.


Please contact me by email for a
copy of these articles if you are interested: f.christiansen at live.se. I will
also be attending the SMM conference next week in New Zealand, and present some
of these results on Wednesday Dec 11 at 09:00 in Castle 2.


Best regards,




Research fellow

Centre for Integrative Ecology

School of Life and Environmental Sciences

Deakin University 

Warrnambool Campus, PO Box 423, Warrnambool, VIC 3280

Phone: +61 3 55633080

Email: f.christiansen at deakin.edu.au, f.christiansen at live.se

Publications: http://scholar.google.com.au/citations?user=vkA5Y3EAAAAJ&hl=en&oi=sra



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