COAST TO COAST: FIRST EVIDENCE FOR TRANSLOCATIONAL COAST TO COAST: FIRST EVIDENCE FOR TRANSLOCATIONAL

MOVEMENTS BY SCOTTISH BOTTLENOSE DOLPHINS (UK)MOVEMENTS BY SCOTTISH BOTTLENOSE DOLPHINS (UK)

Kevin P. Robinson (1)*, Barbara Cheney (2), Laura Mandleberg (3), Sonja M. Eisfeld (1), Marina

Costa (1), Phil Johnston (3), Peter T. Stevick (3)

(1) Cetacean Research & Rescue Unit (CRRU), PO Box 11307, Banff AB45 3WB, Scotland; (2) University of Aberdeen Lighthouse Field Station

(AULFS), School of Biological Sciences, George Street, Cromarty, Ross-shire IV11 8YJ, Scotland; (3) Hebridean Whale & Dolphin Trust

(HWDT), 28 Main Street, Tobermory, Isle of Mull PA75 6NU, Scotland. *Corresponding author, email: kev.robinson@crru.org.uk

The analysis of ranging patterns in cetaceans is crucial to our understanding of the ecology, dynamics, social

structure and evolutionary trajectory of a population. Knowledge of individual patterns of space and habitat use may

be used to identify residency and territoriality, for example, but can also provide important insights on the spatial and

temporal distribution of available resources (Damuth 1981; Stevick et al. 2002). In the Moray Firth in northeast

Scotland, two decades of bottlenose dolphin studies have led us to believe this population is very much isolated in

the north-western North Sea region, with no evidence of exchange between animals in adjacent-studied groups on

the west coast of Scotland or Ireland being found to date (Wilson & Grellier 2002; PT Stevick pers. comm.; O’Brien et

al. in submission). However, in a recent effort to exchange photo-identification data between organisations working

with the species in Scottish waters, the very first evidence for translocational movements of animals between the

Moray Firth and the Inner Hebrides of the west coast of Scotland has been established.

The confirmation of matches between the two geographically-separate communities was made for 7 “marked”

animals recorded along the southern coastline of the outer Moray Firth by the CRRU research team on 4 occasions

in July 2001. These individuals were positively matched by AULFS with subsequent sightings by HWDT made in

2002, 2004 and 2005 around the Inner Hebridean islands of Mull and Skye, approximately 520 kilometres away by

the most direct coastal route as measured using Map Source (Figure 1).

The dorsal fins of the 7 matched individuals are shown below, along with a description of the features used in their

identification:

Whilst direct field-based studies of bottlenose dolphins in the Moray Firth indicate high levels of residency by individuals (Wilson et al 1999; Culloch &

Robinson 2008), the short-term duration of these studies (at around 20 years) provides a poor representation of distributions over longer time-scales. This,

together with the low probability of identifying known individuals outside core study areas, subsequently reduces the chances of detecting movements of

animals over long distances (PM Thompson pers. comm.). In this respect, the present findings clearly demonstrate the power of photo-identification as a

monitoring tool for these long-lived mammals. It seems, in fact, that long-ranging movements of Tursiops truncatus within UK waters may actually be more

common than previously thought (see also O’Brien et al. in submission), and further investigations of the dolphins described in this study have consequently

revealed even greater ranges than those reported here, which must surely be significant in view of restricted Special Areas of Conservation for their

ultimate protection. For example, recaptures of at least 3 of the individuals detailed in this study (i.e. CRRU#231, 233 and 238) have further been confirmed

from as far afield as Galway and Cork in southern Ireland during 2007 and 2008 (JM O’Brien unpublished data) – an additional 830 km from Mull, and a

new distance record for the species. It is also interesting to note that 6 out of the 7 identified bottlenoses making these movements are female. In the past

few weeks, CRRU#231 has further been matched with an animal seen regularly in the mid 1990s from the coast of Cornwall in southwest England (Wood

1998). These findings evidently challenge our current understanding of the wide-scale population structure and dynamics of bottlenose dolphins in UK

waters at this time, and as investigations continue, we hope to publish a more comprehensive account of these results in the very near future.

D07D07

Fig. 1. Map of Scotland showing the position of the Fig. 1. Map of Scotland showing the position of the

Moray Firth and the Inner Hebrides on the east and Moray Firth and the Inner Hebrides on the east and

west coasts respectively. The arrow shows the most west coasts respectively. The arrow shows the most

direct coastal route for bottlenose movements direct coastal route for bottlenose movements

between the CRRU/AULFS and HWDT study sites.between the CRRU/AULFS and HWDT study sites.

Moray FirthMoray Firth

(CRRU/AULFS)(CRRU/AULFS)

InnerInner

HebridesHebrides

(HWDT)(HWDT)SCOTLANDSCOTLAND

① CRRU#229 / HWDT#5024 – this dolphin has a sharply pointed dorsal fin with a prominent lower nick. The multiple scarring/abrasions on its fin and body and its solitary behaviour suggest it is a male, although no observations of the genital slits have been made to date (also photographed in 2006, 2007 and 2008 by HWDT and AULFS).

② CRRU#231 / HWDT#5049 – seen with a young calf in tow in 2001, this adult bottlenose exhibits a number of distinctive nicks and serrations along the trailing edge of its dorsal fin which assisted in its recapture.

③ CRRU#233 / HWDT#5053 – has a distinctly tall, leaning fin with a shallow upper nick and a prominent lower nick in the trailing edge of the dorsal fin. Identified with an older calf by CRRU in 2001 and with calves between 2002 and 2005 by HWDT.

④ CRRU#235 / HWDT#5050 – this adult female (confirmed from observations of the genital slits) has a very recognisable and individually distinctive dorsal fin shape with prominent multiple nicks. Seen with a new-born calf in July 2001.

⑤ CRRU#237 / HWDT#5052 – has a large, falcate dorsal fin with a prominent box-shaped nick in the mid-region of the trailing edge. Appeared to be with an older calf when first recorded in 2001.

⑥ CRRU#238 / HWDT#5051 – also with a tall, leaning dorsal fin, this individual has 2 prominent upper nicks which make it highly distinguishable. Observed with a calf in echelon position during all 4 encounters in July 2001 and between 2002 and 2005 by HWDT which suggests this animal is a female.

⑦ CRRU#242 / HWDT#LEM01 – this animal has a an unusual dent in the anterior tip of the leading edge of its dorsal fin making it highly recapturable. Recorded with a calf in 2001 and between 2002 and 2005.

Culloch RM, Robinson KP (2008) Bottlenose dolphins using coastalCulloch RM, Robinson KP (2008) Bottlenose dolphins using coastal regions adjacent to a regions adjacent to a

Special Area of Conservation (SAC) in northSpecial Area of Conservation (SAC) in north--east Scotland. J Mar east Scotland. J Mar BiolBiol Ass UK 88: Ass UK 88:

12371237––12431243

DamuthDamuth J (1981) Home range, home range overlap and species energy use J (1981) Home range, home range overlap and species energy use among among

herbivorous mammals. herbivorous mammals. BiolBiol J Linn Soc J Linn Soc LondLond 15: 18515: 185––193193

Grellier K, Wilson B (2003) Bottlenose dolphins using the Sound Grellier K, Wilson B (2003) Bottlenose dolphins using the Sound of of BarraBarra, Scotland. , Scotland. AquatAquat

MammMamm 29: 37829: 378––382382

OO’’Brien JM, Brien JM, Berrow SD, McGrath D, OBerrow SD, McGrath D, O’’Connor I, Pesante P, Ryan C, Whooley PConnor I, Pesante P, Ryan C, Whooley P (in (in

submission) submission) Evidence for longEvidence for long--distance movements of bottlenose dolphins (distance movements of bottlenose dolphins (TursiopsTursiops

2323rdrd Annual Conference of Annual Conference of

the European Cetacean the European Cetacean

Society, Istanbul, TurkeySociety, Istanbul, Turkey

22--4 March 20094 March 2009

truncatustruncatus) around the Irish coast using photo) around the Irish coast using photo--identification. identification. J J CetCet ResRes Manage Manage

(and also(and also ECS Poster No. D30)ECS Poster No. D30)

Stevick PT, McConnell BJ, Hammond PS (2002) Patterns of movementStevick PT, McConnell BJ, Hammond PS (2002) Patterns of movement. In: Hoelzel AR . In: Hoelzel AR

(ed) Marine Mammal Biology: An Evolutionary Approach, pp185(ed) Marine Mammal Biology: An Evolutionary Approach, pp185––216. Blackwell 216. Blackwell

Publishing, OxfordPublishing, Oxford

Wilson B, Hammond PS, Thompson PM (1999) Estimating size and assWilson B, Hammond PS, Thompson PM (1999) Estimating size and assessing trends in essing trends in

a coastal bottlenose dolphin population. Ecol App 9a coastal bottlenose dolphin population. Ecol App 9: : 288288––300300

Wood CJ (1998) Movements of bottlenose dolphins around the southWood CJ (1998) Movements of bottlenose dolphins around the south west coast of west coast of

Britain. J ZoolBritain. J Zool Lond 264:155Lond 264:155––163163

CRRU#229

HWDT#5024

①①①① CRRU#231

HWDT#5049

②②②② CRRU#233

HWDT#5053

③③③③ CRRU#235

HWDT#5050

④④④④ CRRU#237

HWDT#5052

⑤⑤⑤⑤ CRRU#238

HWDT#5051

⑥⑥⑥⑥ CRRU#242

HWDT#LEM01

⑦⑦⑦⑦