Dear colleagues,
We are pleased to announce our new publication in Animal Conservation:
Abstract
Growth and body condition can be used as indices of health and fitness, but are difficult to collect for populations of conservation concern where individuals cannot be captured. We incorporated a laser photogrammetry system into boat-based
photo-identification surveys that underpin individual-based studies of cetacean populations. These data were integrated with >25 years of observations from a temperate bottlenose dolphin population in Scotland to investigate the influence of sex on growth
patterns, effects of birth order on calf size and the longer term consequences of variation in early growth. Field measurements of the distance from the blowhole to the dorsal fin were made in multiple years from 87 dolphins that had been followed from birth,
ranging in age from newborn to 26 years. These estimates were validated against direct measurements of 12 individuals that had previously been captured and released in Florida and two study individuals that subsequently stranded. Using relationships derived
from other stranded individuals, age-specific body lengths were used to produce growth curves that were based entirely on remote observations. Multilevel regression growth curve analyses suggested males and females showed similar patterns of growth, unlike
bottlenose dolphins in sub-tropical areas, and growth was best described by a Richards’ growth curve. Newborn length was unrelated to sex; however, females’ first calves were shorter than subsequent calves. Sample sizes remain small, yet there was evidence
of fitness consequences of variation in calf length; calves that died in their first winter were significantly shorter than those that survived. The incorporation of this simple-to-use and inexpensive method into individual-based photo-identification studies
provides new opportunities to non-invasively investigate drivers of variation in growth and the demographic consequences of variation in early growth in cetaceans from protected populations.
Our article is published online for early view and open access at
http://onlinelibrary.wiley.com/doi/10.1111/acv.12384/full
Kind regards,
Barbara
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Barbara Cheney
Research Fellow
Lighthouse Field Station
University of Aberdeen
George Street
Cromarty
Ross-shire IV11 8YL
Tel: 01381 600548
