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This study investigated the distribution of a population of bottlenose dolphins Tursiops truncatus resident in the Moray Firth off north-eastern Scotland. Results add to existing information from studies in tropical areas to provide a better understanding of area use in this species. Boat-based surveys and photo-identification techniques were used to study the distribution and movements of individually recognizable dolphins over a 3-year per-Dolphins were seen in all months of the year, but there were consistent seasonal fluctuations in the number of individuals present. Numbers were low in winter and spring and peaked in summer and autumn. Dolphins were seen throughout the survey area but were concentrated in three regions. Each had similar topographic features being centred on deep, narrow channels subject to strong tidal flows. Area use by dolphins changed with season. The outer part of the inner Moray Firth study area was used for most of the year and areas closer to the head of the firth were used seasonally. The summer increase in numbers of dolphins in the inner Moray Firth was not simply due to incomers diluting an already resident population. Instead, there was a stratified movement of all individuals. This persistent geographical stratification suggests that competition between individuals or social groupings may shape spatial distribution in this population. Individuals exhibited rapid movements across the population‘s range. For instance, one individual was sighted at locations 190 km apart within a 5-day period. In terms of conservation, the high use of areas at the mouths of the inner firths warrants special attention. Furthermore, the stratification patterns amongst dolphins suggest that individuals do not move freely within the inner Moray Firth and therefore may be unable to move away from localized disturbance or pollution. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]