Robert J. Reid

ISOLATION OF BRUCELLA SPECIES FROM CETACEANS, SEALS AND AN OTTER

Brucella organisms which differed from the recognised species of the genus, were isolated from nine seals, eight cetaceans and one otter. A method is described for the isolation of Brucella species from sea mammals and the first isolations of Brucella species are recorded from an Atlantic white-sided dolphin (Lagenorhynchus acutus), two striped dolphins (Stenella coeuleoalba), a hooded seal (Cystophora cristata), a grey seal (Halichoerus grypus) and a European otter (Lutra lutra). There were differences in the culture media required for the primary isolation of the organisms and in their dependency on carbon dioxide. Subcutaneous lesions, when present, always yielded a confluent growth. The organisms were isolated from seven of 14 spleen samples and also from the mammary glands, uterus, testes and blood and the mandibular, gastric, iliac, sub-lumbar and colorectal lymph nodes.

Evidence for infanticide in bottlenose dolphins: an explanation for violent interactions with harbour porpoises?

Most harbour porpoises found dead on the north–east coast of Scotland show signs of attack by sympatric bottlenose dolphins, but the reason(s) for these violent interactions remains unclear. Post–mortem examinations of stranded bottlenose dolphins indicate that five out of eight young calves from this same area were also killed by bottlenose dolphins. These data, together with direct observations of an aggressive interaction between an adult bottlenose dolphin and a dead bottlenose dolphin calf, provide strong evidence for infanticide in this population. The similarity in the size range of harbour porpoises and dolphin calves that showed signs of attack by bottlenose dolphins suggests that previously reported interspecific interactions could be related to this infanticidal behaviour. These findings appear to provide the first evidence of infanticide in cetaceans (whales, dolphins and porpoises). We suggest that infanticide must be considered as a factor shaping sociality in this and other species of cetaceans, and may have serious consequences for the viability of small populations.

Considering the temporal when managing the spatial: a population range expansion impacts protected areas-based management for bottlenose dolphins

Management of marine species has increasingly focused on key site protection. Initiatives to protect bottlenose dolphins, Tursiops truncatus, under the EU Habitats Directive reflect this trend. The boundaries of the Moray Firth candidate Special Area of Conservation (cSAC) were intended to include the main Scottish population’s core range, following research conducted in the 1980s and early 1990s. However, during implementation, anecdotal sightings increased outside the cSAC. Here, the authors examine existing datasets to identify whether these reports reflect simply elevated awareness among public observers or real changes in distribution. Dolphins photo-identified in areas originally considered to be outside the population’s range confirmed they originated from the protected population. These individuals became rarer within the cSAC during the 1990s. Scottish bottlenose dolphins kill harbour porpoises, Phocoena phocoena, and carcasses from these interactions also became more frequent outside the cSAC during the 1990s. These results indicate mobility of this ‘resident’ dolphin population on a timescale similar to that of the implementation of the European Directive designed to protect it. Consequently, this and other similar designations, may afford less protection than originally envisioned and the authors recommend, therefore, that the potential for long-term mobility should be actively incorporated into such management structures from the outset.

Brucella species infection in North Sea seal and cetacean populations.

albumin to 1:750 and 1:1500. Overnight incubation at 4°C was the best condition for the different primary antibodies employed. Swine anti-rabbit immunoglobulins 1:20 for use as a secondary antibody and PAP complex 1:100 were both made up in phosphate buffered saline with I per cent bovine serum albumin and incubated for 30 minutes at room temperature. To detect the immune complexes, the sections were incubated in a solution of 60 mg of 3,3-diamino-benzidine tetrahydrochloride, 100 ,ul hydrogen peroxide and 100 ml of phosphate buffered saline for eight minutes and counterstained with Mayers haematoxylin. Ganglia from all horses with either mal seco or EGS showed

Stomach contents of bottlenose dolphins ( Tursiops truncatus ) in Scottish waters

Data on stomach contents of ten bottlenose dolphins (Tursiops truncatus) stranded and by-caught around Scotland (UK) between 1990 and 1999 are presented. Although the species is resident in the Moray Firth (north-east Scotland), little previous information exists on the feeding habits of the species in Scottish waters. Cod (Gadus morhua), saithe (Pollachius virens) and whiting (Merlangius merlangus) were found to be the main prey eaten although several other fish species were also found, including salmon (Salmo salar) and haddock (Melanogrammus aeglefinus), and also cephalopods.

Genetic differentiation among North Atlantic killer whale populations

Population genetic structure of North Atlantic killer whale samples was resolved from differences in allele frequencies of 17 microsatellite loci, mtDNA control region haplotype frequencies and for a subset of samples, using complete mitogenome sequences. Three significantly differentiated populations were identified. Differentiation based on microsatellite allele frequencies was greater between the two allopatric populations than between the two pairs of partially sympatric populations. Spatial clustering of individuals within each of these populations overlaps with the distribution of particular prey resources: herring, mackerel and tuna, which each population has been seen predating. Phylogenetic analyses using complete mitogenomes suggested two populations could have resulted from single founding events and subsequent matrilineal expansion. The third population, which was sampled at lower latitudes and lower density, consisted of maternal lineages from three highly divergent clades. Pairwise population differentiation was greater for estimates based on mtDNA control region haplotype frequencies than for estimates based on microsatellite allele frequencies, and there were no mitogenome haplotypes shared among populations. This suggests low or no female migration and that gene flow was primarily male mediated when populations spatially and temporally overlap. These results demonstrate that genetic differentiation can arise through resource specialization in the absence of physical barriers to gene flow.

Linking sandeel consumption and the likelihood of starvation in harbour porpoises in the Scottish North Sea: could climate change mean more starving porpoises?

Sandeels are known to be negatively affected by climate change in a number of ways. This study investigated whether these changes are affecting the harbour porpoise (Phocoena phocoena), a species which consumes sandeels. Porpoise diet was examined in spring (March–May), a critical time of year for survival when sandeels are important prey, from 1993 to 2001 to provide baseline information on the proportion of sandeels consumed. When data from spring 2002 and 2003 were compared to these baseline data, the diet was found to be substantially different, with a significant and substantially smaller proportion of sandeels being consumed in March and May. There were also differences in the number of porpoises starving between the two time periods (33% in spring 2002 and 2003 died of starvation, but only 5% in the baseline period). This suggests that a lower proportion of sandeels in the diet of porpoises in spring increases the likelihood of starvation. Therefore, we suggest that the negative effects of climate change on sandeel availability may have serious negative effects on harbour porpoise populations in the North Sea by increasing the likelihood of starvation in spring.

Stable carbon and nitrogen isotope ratio profiling of sperm whale teeth reveals ontogenetic movements and trophic ecology

Teeth from male sperm whales (Physeter macrocephalus) stranded in the North-eastern Atlantic were used to determine whether chronological profiles of stable isotope ratios of C (δ13C) and N (δ15N) across dentine growth layers could be used to detect known ontogenetic benchmarks in movements and trophic ecology. Profiles showed a general decrease in δ13C (medianxa0=xa01.91‰) and an increase in δ15N (medianxa0=xa02.42‰) with age. A marked decline in δ13C occurred for all 11 teeth around 9–10xa0years and again for six individuals around 20xa0years. After the early twenties the δ13C continued to decline with age for all teeth. These results are consistent with males segregating from natal groups in low latitudes with the onset of puberty between 4 and 15xa0years and gradually dispersing pole-ward into 13C-depleted temperate waters. Penetration into further depleted, productive high latitudes after the age of 20 might facilitate the spurt of accelerated growth rate observed around this age. Breeding migrations back to lower latitudes were not reflected in the δ13C profiles possibly due to being short compared to the time spent feeding in high latitudes. The timings of marked isotopic change in the δ15N profiles reflect those of the δ13C profiles, suggesting a link between dietary changes and movements. The observed increase in δ15N with age is likely to be caused by a trophic level increase as males grow in size, probably feeding on larger prey. An additional explanation could be that, in the higher latitudes of the North Atlantic, the main prey source is the high trophic level squid Gonatus fabricii. Also, the lower latitudes from where males disperse are depleted in basal 15N. Profiles of δ13C and δ15N in sperm whale teeth gathered from different regions, sexes, and periods in time, could provide a unique way to understand the ecology of this species across different oceans.

Mitochondrial genetic diversity and population structuring of UK bottlenose dolphins (Tursiops truncatus): is the NE Scotland population demographically and geographically isolated?

Concern has been expressed over the status of the bottlenose dolphin population that uses the Moray Firth and adjacent waters in NE Scotland. Consequently, part of this populations range has been proposed as a Special Area of Conservation. Efforts to manage and monitor the status of this population require information on the level of genetic diversity within the population and its genetic relatedness to neighbouring populations to appropriately designate units for management and monitoring. Here we examine mitochondrial genetic diversity within the NE Scotland population, and compare this to other regions around the UK and Ireland. Sequence analysis of 549bp of the mitochondrial DNA control region identified eight unique haplotypes in a sample of 29 individuals. Analysis of molecular variance suggests that the Moray Firth population is genetically more closely related to Welsh animals than to its nearest neighbour population in west Scotland. Furthermore, measures of within-population genetic diversity were markedly lower in the Moray Firth than any other sampled region. The low levels of mtDNA genetic variability observed and its apparent geographic isolation provide further support for the precautionary approach currently being applied to the management of this population, despite the lack of direct evidence of harm.

Patterns of marine turtle mortality in British waters (1992-1996) with reference to tissue contaminant levels

Mortality patterns of marine turtles entangled in fishing gear, found dead at sea or stranded dead on and around the coast of Britain in the period 1992–1996 are described. Of a total of 38 dead turtles identified, 35 were leatherback turtles ( Dermochelys coriacea ) and three were loggerhead turtles ( Caretta caretta ). All D. coriacea were considered adults or subadults nearing sexual maturity. Six individuals were assessed as females, ten were classified as males and 19 were not sexed. Dermochelys coriacea (N=20 measured) ranged from 120 to 210 cm in curved carapace length (mean, 152 cm). The three C. caretta were juveniles, and ranged from 15 to 30 cm curved carapace length. Possible origins, causes of mortality and interactions with fisheries are discussed. In addition, contaminant levels were determined in the tissues of three D. coriacea . Concentrations of organic contaminants determined were found to be low.