Graz. Schloßberg.

Blick zum Schloßberg mit Hauptbrück

Note: Presenting vertebral deformities in bottlenose dolphin Tursiops truncatus calves from a protected population in northeast Scotland

Photographs collected during a 23 yr photo-identification study in the Moray Firth were examined to assess the prevalence, type and severity of vertebral deformations present in bottlenose dolphin Tursiops truncatus calves. Fifteen cases of presenting spinal anomalies (scoliosis, kyphosis, lordosis and combinations thereof) of variable severity were identified in 7.4% of all known calves from the population. Thirteen of the 15 anomalies were either manifest from birth or acquired from an early age, as ascertained from longitudinal sightings histories of their mothers. Most afflicted calves died during early development or shortly after maternal separation. However, 3 survived to adulthood and persist in the population to date, in addition to 2 dependent infants whose fate remains to be established. At 15+ yr of age, the oldest surviving individual was remarkably one of the most severe cases identified, highlighting the ability of these delphinids for adaptation to such gross structural deformities. The aetiology of the observed conditions could be attributed to a range of causative factors that may have implications for the well-being and health of this North Sea coastal dolphin population, a topic which merits further investigation

The range of IBIs documented for female <i>T</i>. <i>truncatus</i> in the outer southern Moray Firth study area, relative to previous calving success and possible gaps in reproductive histories.

<p>The range of IBIs documented for female <i>T</i>. <i>truncatus</i> in the outer southern Moray Firth study area, relative to previous calving success and possible gaps in reproductive histories.</p

Map of northeast Scotland showing the position of the survey area along the southern coastline of the outer Moray Firth, to the east of the Special Area of Conservation (SAC).

<p>Dedicated boat surveys for bottlenose dolphins were conducted between May and October 1997 to 2016 using selected routes within the core study area, between the coastal ports of Lossiemouth and Fraserburgh.</p

Female reproductive success and calf survival in a North Sea coastal bottlenose dolphin (<i>Tursiops truncatus</i>) population - Fig 2

<p>Photographs of female bottlenose dolphins from the Moray Firth with first-year calves: (A) one of the highly successful mothers (ID#065) with a new-born calf; (B) and (C) cooperative female groups with calves of similar ages in tow.</p

The reproductive parameters of female bottlenose dolphins estimated from long-term mark-recapture studies in the southern outer Moray Firth from 1997 to 2016 inclusive.

<p>Weaning age for survival was considered to be to two years of age, after which calves were regarded to be fully independent of their mothers. See text for information on how RS, calving rate and fecundity were calculated.</p

Individual variation in reproductive success observed in female bottlenose dolphins from the Moray Firth study population for mothers with ≥3 documented births of known fate.

<p>Unless already deceased, any calves born towards the end of the sampling period (in 2016) were not included, as they had not reached the minimum weaning age.</p

The seasonality of bottlenose dolphin births in the outer southern Moray Firth and the average monthly sea temperatures measured during encounters.

<p>The seasonality of bottlenose dolphin births in the outer southern Moray Firth and the average monthly sea temperatures measured during encounters.</p

The total number of individuals, number of reproductive female bottlenose dolphins and the number of calves recorded in the outer southern Moray Firth study area from 1997 to 2016 inclusive.

<p>The total number of individuals, number of reproductive female bottlenose dolphins and the number of calves recorded in the outer southern Moray Firth study area from 1997 to 2016 inclusive.</p