Visual and morphometric description of feral horse hooves from Sable Island National Park Reserve.

Objective: To visually evaluate and morphometrically describe a sample of abnormal hooves from Sable Island horses that died between 2007 and 2013. Animal: Equine. Procedure: An opportunistic sample of 356 abnormal hooves from horses inhabiting Sable Island National Park Reserve (Canada) was collected postmortem between 2007 and 2013 from 101 Sable Island horses. These hooves were assessed for abnormalities in conformation through visual and morphometric evaluation. Results: On visual and morphometric evaluation, 100% of horses (101/101) had abnormal hoof conformation when compared to a domestic horse hoof model. Specific abnormalities from visual evaluation included long heels (85%); medial, lateral, and dorsal flares (45, 78, and 46% of horses, respectively); and cracking (62%). Specific abnormalities determined from morphometry of the hooves included contracted heels (87%), hoof imbalances including mediolateral imbalance (61%), and hoof length greater than width (100%). Conclusion: Sable Island horses had various hoof abnormalities such as hoof capsule flaring; long, contracted heels; and mediolateral imbalance. These abnormalities have been observed in other feral horse populations living on soft substrates. Given the potential impact of hoof abnormalities on the welfare status of the Sable Island horses, further studies are warranted, including estimation of the prevalence of hoof abnormalities and direct observation of horse gait and behavior. Clinical relevance: The significance of the hoof abnormalities for the health of the Sable Island horses is difficult to determine but the issue highlights the importance of further study to investigate the impact on the horses' welfare.

Description visuelle et morphométrique des sabots de chevaux sauvages de la réserve de parc national de l'Île-de-Sable. Objectif: Évaluer visuellement et décrire morphométriquement un échantillon de sabots anormaux de chevaux de l'île de Sable décédés entre 2007 et 2013. Animal: Cheval. Procédure: Un échantillon opportuniste de 356 sabots anormaux provenant de chevaux habitant la réserve de parc national de l'Île-de-Sable (Canada) a été prélevé post-mortem entre 2007 et 2013 sur 101 chevaux de l'île-de-Sable. Ces sabots ont été évalués pour déceler des anomalies de conformation par une évaluation visuelle et morphométrique. Résultats: Lors de l'évaluation visuelle et morphométrique, 100 % des chevaux (101/101) présentaient une conformation de sabot anormale par rapport à un modèle de sabot de cheval domestique. Les anomalies spécifiques de l'évaluation visuelle comprenaient les talons longs (85 %); poussées médiales, latérales et dorsales (respectivement 45, 78 et 46 % des chevaux); et fissuration (62 %). Les anomalies spécifiques déterminées à partir de la morphométrie des sabots comprenaient des talons contractés (87 %), des déséquilibres des sabots, notamment un déséquilibre médiolatéral (61 %) et une longueur du sabot supérieure à la largeur (100 %). Conclusion: Les chevaux de l'île-de-Sable présentaient diverses anomalies aux sabots, telles qu'un évasement de la boîte cornée; talons longs et contractés; et déséquilibre médiolatéral. Ces anomalies ont été observées chez d'autres populations de chevaux sauvages vivant sur des substrats mous. Compte tenu de l'impact potentiel des anomalies des sabots sur le bien-être des chevaux de l'Île-de-Sable, d'autres études sont justifiées, notamment l'estimation de la prévalence des anomalies des sabots et l'observation directe de la démarche et du comportement des chevaux. Pertinence clinique: L'importance des anomalies des sabots pour la santé des chevaux de l'Île-de-Sable est difficile à déterminer, mais la question souligne l'importance d'une étude plus approfondie pour étudier l'impact sur le bien-être des chevaux.(Traduit par Dr Serge Messier).

An Estimation of Lameness in Sable Island Horses Using Radiographic Evaluation of the Distal Phalanx and Hoof Capsule.

Laminitis is a painful condition that causes lameness in horses. However, monitoring this condition in feral horses is logistically difficult. Laminitis can be detected postmortem, as inflammation of the sensitive laminae of the hoof changes the relative location of the bony structures within the hoof capsule. Thus, evaluation of cadavers may be used to estimate laminitis prevalence in feral populations of horses. The objective of this study was to estimate the prevalence of laminitis in feral horses inhabiting the Sable Island National Park Reserve, Canada, using radiographic imagery on the hooves of naturally deceased horses. Radiographic indicators evaluated included coronary band extensor process distance (CE), capsular rotation (CR), palmar angle (PA), ratio of the dorsal hoof wall thickness to the length of the distal phalanx (DHWT:P3) and sole depth (SLD). Each value measured indicated the following prevalence of laminitis: CE 0% (97.5% Confidence Interval (CI) 0-4.51%), 8.75% CR (95%CI 3.59-17.2%), PA 25% (95% CI 15.99-35.94%), DHWT:P3 6.25% (95%CI 2.06-14.0%) and 65% SLD (95% CI 53.52-75.33%). The majority of indices measured for laminitis were low. These findings suggest that laminitis is fairly infrequent in the Sable Island horses evaluated in this study.

Evaluating Canada's single-use plastic mitigation policies via brand audit and beach cleanup data to reduce plastic pollution.

Single-use plastics (SUPs) represent a major threat to marine environments and require proactive policies to reduce consumption and mismanagement. Many SUP management strategies exist to reduce SUP use and mitigate environmental impacts, including extended producer responsibility (EPR), deposit-return schemes, SUP bans or taxes, and public outreach and education. This study analyzed brand audit and beach cleanup data in four densely populated Canadian cities (Vancouver, Toronto, Montréal, Halifax) and a remote island (Sable Island) to determine efficacy of ongoing SUP mitigation measures. Cities were found to have similar litter type proportions, and six brands were found to disproportionally contribute to Canadian SUP litter, comprising 39% of branded litter collected. Results confirm that current Canadian SUP management appears to be insufficient to address leakage of SUPs into the environment. Recommendations to strengthen SUP management strategies and mitigate plastic pollution are recommended to improve future Canadian SUP reduction policies.

PATHOLOGY OF NORTHERN FULMARS (FULMARUS GLACIALIS) AND SHEARWATERS BEACHED ON SABLE ISLAND, NOVA SCOTIA, CANADA.

Marine birds are frequently found dead on beaches, either from natural or from anthropogenic causes. Complete necropsies of those carcasses can provide valuable information, particularly for pelagic species, such as Northern Fulmars (Fulmarus glacialis) and shearwaters, which come to land only to breed and for which information on diseases that may affect them is, therefore, sparse. Between 2000 and 2012, 315 carcasses of four species of Procellariiformes (173 Northern Fulmars, 89 Great Shearwaters [Ardenna gravis], 50 Sooty Shearwaters [Ardenna grisea], and three Cory's Shearwaters [Calonectris diomedea]) were collected on Sable Island, Nova Scotia, Canada, an isolated island near the edge of the continental shelf. A complete necropsy, including examination for the presence of ingested plastic, was performed on all carcasses. Most (70%) of these birds were immature. The cause of death was undetermined in 22% (n=70) of the birds: 36% (62/173) of the Northern Fulmars, 4% (4/89) of the Great Shearwaters, 6% (3/50) of the Sooty Shearwaters, and 33% (1/3) of the Cory's Shearwaters. Emaciation was considered the primary cause of death in 91% of the remaining 245 birds: 87% (97/111) of the Northern Fulmars, 92% (78/85) of the Great Shearwaters, 100% (47/47) of the Sooty Shearwaters, and 100% (2/2) of the Cory's Shearwaters. Notable primary causes of death other than emaciation included mycobacteriosis and neoplasia in Northern Fulmars and transmural parasitic proventriculitis in Great Shearwaters. For Northern Fulmars, nutritional condition (as determined semiquantitatively) was compared with other parameters. Birds in good nutritional condition had heavier body mass and flight muscle mass than those in poor nutritional condition (P<0.01). More adults were in poor nutritional condition than expected by chance (91%; χ2=8.23, P<0.01), whereas only 57% of immature birds were in poor condition. There was no relationship between nutritional condition and sex or mass of ingested plastic. Our study provides information on some previously unsuspected health threats in Procellariiformes.

Small Ne of the Isolated and Unmanaged Horse Population on Sable Island.

For small, isolated populations 2 common conservation concerns relate to genetic threats: inbreeding and negative consequences associated with loss of genetic diversity due to drift. Mitigating these threats often involves conservation actions that can be controversial, such as translocations or captive breeding programs. Although such actions have been successful in some situations, in others they have had undesirable outcomes. Here, we estimated the effective population size (N e ) of the Sable Island horses to assess the risk to this population of these genetic threats. We found surprising consistency of N e estimates across the 5 different methods used, with a mean of 48 effective individuals. This estimate falls below the 50 criterion of the "50/500 rule," below which inbreeding depression is a concern for population viability. However, simulations and knowledge of population history indicate that this population is still in its early stages of approaching equilibrium between mutation, drift, and genetic diversity; and no negative consequences have been identified that could be associated with inbreeding depression. Therefore, we do not recommend taking management action (such as translocations) at this stage. Rather, we propose continued monitoring of genetic diversity and fitness over time so that trends and any substantial changes can be detected. This represents one of the few unmanaged horse populations in the world, and therefore these data will not only alert us to serious concerns regarding their conservation status, but will also provide a wealth of information about how natural processes drive patterns of reproduction, mortality, and population growth over time.

Plastic ingestion by fulmars and shearwaters at Sable Island, Nova Scotia, Canada.

Plastic pollution is widespread in the marine environment, and plastic ingestion by seabirds is now widely reported for dozens of species. Beached Northern Fulmars, Great Shearwaters, Sooty Shearwaters and Cory's Shearwaters are found on Sable Island, Nova Scotia, Canada regularly, and they can be used to assess plastic pollution. All species except Cory's Shearwaters contained plastic debris in their gastrointestinal tracts. Northern Fulmars, Sooty Shearwaters and Great Shearwaters all showed high prevalence of plastic ingestion (>72%), with Northern Fulmars having the highest number and mass of plastics among the species examined. There was no difference in plastic ingestion between sexes or age classes. In all species user plastics made up the majority of the pieces found, with industrial pellets representing only a small proportion in the samples. Sable Island could be an important monitoring site for plastic pollution in Atlantic Canada.

Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis.

Species biogeography is a result of complex events and factors associated with climate change, ecological interactions, anthropogenic impacts, physical geography, and evolution. To understand the contemporary biogeography of a species, it is necessary to understand its history. Specimens from areas of localized extinction are important, as extirpation of species from these areas may represent the loss of unique adaptations and a distinctive evolutionary trajectory. The walrus (Odobenus rosmarus) has a discontinuous circumpolar distribution in the arctic and subarctic that once included the southeastern Canadian Maritimes region. However, exploitation of the Maritimes population during the 16th-18th centuries led to extirpation, and the species has not inhabited areas south of 55°N for ∼250 years. We examined genetic and morphological characteristics of specimens from the Maritimes, Atlantic (O. r. rosmarus) and Pacific (O. r. divergens) populations to test the hypothesis that the first group was distinctive. Analysis of Atlantic and Maritimes specimens indicated that most skull and mandibular measurements were significantly different between the Maritimes and Atlantic groups and discriminant analysis of principal components confirmed them as distinctive groups, with complete isolation of skull features. The Maritimes walrus appear to have been larger animals, with larger and more robust tusks, skulls and mandibles. The mtDNA control region haplotypes identified in Maritimes specimens were unique to the region and a greater average number of nucleotide differences were found between the regions (Atlantic and Maritimes) than within either group. Levels of diversity (h and π) were lower in the Maritimes, consistent with other studies of species at range margins. Our data suggest that the Maritimes walrus was a morphologically and genetically distinctive group that was on a different evolutionary path from other walrus found in the north Atlantic.

Genetic diversity in a feral horse population from Sable Island, Canada.

The present-day Sable Island horse population, inhabiting an island off the eastern coast of Canada, is believed to have originated mainly from horses confiscated from the early French settlers in Nova Scotia in the latter half of the 18th century. In 1960, the Sable Island horses were given legal protected status and no human interference has since been allowed. The objective of this study was to characterize the current genetic diversity in Sable Island horses in comparison to 15 other horse breeds commonly found in Canada and 5 Spanish breeds. A total of 145 alleles from 12 microsatellite loci were detected in 1093 horses and 40 donkeys. The average number of alleles per locus ranged from 4.67 in the Sable Island horse population to 8.25 in Appaloosas, whereas the mean observed heterozygosity ranged from 0.626 in the Sable Island population to 0.787 in Asturcons. Various genetic distance estimates and clustering methods did not permit to support that the Sable Island horses originated from shipwrecked Spanish horses, according to a popular anecdote, but closely resemble light draft and multipurpose breeds commonly found in eastern Canada. Based on the Weitzman approach, the loss of the Sable Island horse population to the overall diversity in Canada is comparable or higher than any other horse breed. The Sable Island horse population has diverged enough from other breeds to deserve special attention by conservation interest groups.

Characterization and source of oil contamination on the beaches and seabird corpses, Sable Island, Nova Scotia, 1996-2005.

During April 1996-May 2005, 2343 oiled seabird corpses were recorded in beach surveys conducted on Sable Island, Nova Scotia. One hundred eighty-three samples of oil were collected from the beaches and from the feathers of bird corpses. Gas chromatographic (GC/FID) analysis was used to identify generic oil type and likely marine source. During this period, at least 74 marine oil discharge events were probably responsible for beached pelagic tar and contamination of seabird corpses found on Sable Island, of which 77.0% were crude oils, 14.9% were fuel oils, and 8.1% were bilge oil mixtures. While fuel and bilge oils may be discharged by all vessel and platform types, crude oil discharges are associated with tanker operations. This study demonstrates that oiling of the sea from tankers remains a serious wildlife issue in the Northwest Atlantic.

Health status of harp seals (Phoca groenlandica) and hooded seals (Cystophora cristata) on Sable Island, Nova Scotia, Canada, concurrent with their expanding range.

Beach surveys for harp (Phoca groenlaandica) and hooded (Cystophora cristata) seals documented a dramatic increase in their numbers on Sable Island in mid 1990s. In the 1980s, no more than five animals of both species were observed on this island each year, however, during late 1994 to 1998, 1,191 harp and 870 hooded seals, mostly young animals, were recorded. Although some of these seals had been killed by sharks, most (roughly 75%) were found alive or as intact carcasses on the beach, and some of the live seals were later found dead. Emaciation/starvation was considered the primary cause of death in seals that were not obviously killed by sharks. Factors that may have compounded this poor body condition included gastric impaction with abnormal ingesta, hemorrhagic diathesis possibly induced by parasitic migration and secondary vasculitis, and stomatitis (in hooded seals only). Some harp and hooded seals expanding their range in recent years may be unable to feed successfully, although the reasons for this are unclear.