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Article Excerpt
ABSTRACT. Over the last several decades, elders and hunters of the Innu Nation in Labrador, Canada, have expressed concerns over perceived declines in environmental health and the integrity of country food, including caribou. The primary objective of this study was to determine links between specific health parameters and contaminants found in caribou from the George River herd. Twenty-seven caribou killed by local Innu hunters between February and December 2001 were evaluated for gross and microscopic pathology, body condition, liver parasitology, and contaminant levels in kidney and fat. Overall, the sampled caribou appeared to be in adequate body condition for the time of year, and no clinically significant lesions were found. Concentrations of selenium, metals (Hg, Cd, and Pb), 20 organochlorine pesticides (HCB, [alpha]-HCH, [gamma]-HCH, aldrin, dieldrin, methoxychlor, mirex, [alpha]- and [beta]-endosulfan, heptachlor, heptachlor epoxide, [gamma]-CHL, cis-CHL, trans-nonachlor, and o,p'- and p,p'-DDD, DDE, DDT), and 24 PCB congeners were within the ranges reported for caribou in Canada. In general, contaminant levels were relatively low, with the exception of cadmium in kidneys (geometric mean: 6.5 [micro]g/g wet weight; range: 1.5-44.0 [micro]]g/g). Two types of liver parasites were found: the liver fluke Fascioloides magna (prevalence: 78%; geometric mean abundance: 4.2 flukes/caribou) and a tapeworm larva consistent with Taenia hydatigena (prevalence: 50%; geometric mean abundance: 0.6 larvae/caribou). Using multiple variable regression analysis, we found renal concentrations of cadmium to be positively associated, and selenium to be negatively associated, with F. magna abundance.
Key words: body condition, environmental contaminants, liver fluke, Fascioloides magna, parasites, Rangifer tarandus, cadmium, Innu people, Labrador, George River caribou herd
RESUME. Ces dernieres decennies, les aines et les chasseurs de la nation montagnaise du Labrador, au Canada, ont exprime des inquietudes au sujet du declin de la sante de l'environnement et de l'integrite de la nourriture provenant de la campagne, telle que le caribou. L'objectif principal de cette etude consistait a determiner les liens qui existent entre certains parametres de sante precis et les contaminants se trouvant dans le caribou du troupeau de la riviere George. Vingt-sept caribous ayant ete tues par les chasseurs montagnais de la region entre les mois de fevrier et de decembre 2001 ont subi des examens pathologiques macroscopiques et microscopiques, en plus d'avoir ete evalues pour en determiner l'etat du corps, la parasitologie du foie et les taux de contaminants dans le foie et le gras. Dans l'ensemble, l'etat des corps de caribous echantillonnes semblait adequat pour cette periode de l'annee et aucune lesion clinique importante n'a ete signalee. Les concentrations de selenium, de metaux (Hg, Cd et Pb), de 20 pesticides organochlores (HCB, [alpha]-HCH, [gamma]-HCH, aldrine, dieldrine, methoxychlore, mirex, [alpha]- et [beta]-endosulfane, heptachlore, heptachlorepoxyde, [gamma]-CHL, cis-CHL, trans-nonachlore ainsi que o,p'- et p,p'-DDD, DDE, DDT) et de 24 congeneres de PCB s'etablissaient dans les etendues signalees pour le caribou au Canada. En general, les niveaux de contaminants etaient relativement faibles, a l'exception du cadmium se trouvant dans les reins (moyenne geometrique: 6.5 [micro]g/g poids humide; etendue: 1,5-44,0 [mu]g/g). Deux types de parasites du foie ont ete trouves: la douve Fascioloides magna (prevalence: 78 %; abondance moyenne geometrique: 4,2 douves/caribou) et un cestode du genre Taenia hydatigena (prevalence: 50 %; abondance moyenne geometrique: 0,6 larves/caribou). Nous avons egalement realise une analyse de
INTRODUCTION
Caribou (Rangifer tarandus) is the dominant large terrestrial herbivore in many northern ecosystems. The George River herd (GRH) is the largest caribou population in eastern Canada. The range of the GRH includes much of Labrador and extends across the Ungava Peninsula well into the province of Quebec (Fig. 1). The GRH population underwent rapid growth up to the mid-1990s, when it was estimated at approximately 700000 animals, and has recently declined to approximately 400000 animals (R. Otto, pers. comm. 2007).
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Members of the Innu Nation in Labrador hunt caribou from the GRH on a seasonal basis. Caribou have important nutritional, cultural, and spiritual significance for the Innu people (Armitage, 1990; Loring, 1997), who are concerned for the health of Labrador caribou populations because of industrial development and other potential impacts on the ecosystem, such as environmental contaminants (Innes, 1998).
Research programs such as the Northern Contaminants Program and the Arctic Monitoring and Assessment Programme have recently brought attention to the issue of environmental contaminants such as metals, organochlorines (OCs) and radionuclides in northern ecosystems in Canada and worldwide (Fisk et al., 2003; AMAP, 2004, 2005). Many studies of environmental contaminants throughout northern Canada have consistently found elevated cadmium concentrations in the kidneys of moose and caribou (Muir et al., 1997; Gamberg et al., 2005), including the GRH caribou (Crete et al., 1989; Robillard et al., 2002).
The most important route of contaminant exposure for terrestrial animals is usually through food consumption (Muir et al., 1997). The diet of GRH caribou consists of a variety of plant types, including grasses and sedges, woody stems and twigs, leaves, lichens, and mosses (Crete et al., 1990). Lichens and mosses, which lack root systems, take up metals and minerals directly from the air and are often used to monitor atmospheric deposition of metals (Dietz et al., 1998). While tissue contaminant levels have been well reported, the potential biological effects of contaminants in cervids, including caribou, are not well understood. Several published studies investigating the biology and ecology of the GRH have included health parameters such as parasite burdens and body condition (e.g., Parker, 1981; Huot and Beaulieu, 1985; Lankester and Luttich, 1988); however, the relationship between health parameters and contaminant levels has not been examined in this caribou population.
The present study, carried out in collaboration with the Innu Nation, evaluates health parameters of caribou harvested by Innu hunters in Labrador in relation to tissue concentrations of environmental contaminants. The specific objectives were 1) to determine body condition and hepatic parasite burdens of caribou killed during the regular subsistence hunt and examine selected tissues for gross and microscopic pathological abnormalities; 2) to determine the tissue concentrations of selenium, metals, and a wide range of OC contaminants in these caribou; and 3) to examine the relationship between the specific health parameters and tissue contaminant levels in the caribou through multiple regression analyses.
MATERIALS AND METHODS
Caribou Locations and Sample Collection
To ensure that the results were clearly representative of the animals that make up the Innu harvest, we chose the sample population of 27 GRH caribou from those that were shot during the regular subsistence hunt by residents of the Labrador Innu communities of Sheshatshit and Utshimassit (Davis Inlet) (Fig. 1). The caribou were killed in south-central and coastal-northern Labrador (approximately 61[degrees] W - 64[degrees] W and 53[degrees]30'N-56[degrees] N). Samples were collected from caribou killed in February 2001 (winter, n = 13) and in October and December 2001 (fall, n = 14).
All methods for collection, handling, processing and disposal of samples were agreed upon by the Innu Nation co-researchers, community elders, hunters and their family members, and the researchers from the Atlantic Veterinary College (AVC), University of Prince Edward Island. In order to retain strong community acceptance of the research and its findings, researchers placed a high degree of importance on maintaining the traditions surrounding the hunt and ensuring that the caribou were still considered to be suitable for community distribution and consumption after sampling.
Once killed, each caribou was cleaned by removing the gastrointestinal tract, leaving the thoracic cavity intact, and comments from the hunter regarding the perceived health of the animal were recorded.
Gross examination of the carcass and organs was limited to the exterior of the animal and to the abdominal organs (stomachs, intestines, liver, kidneys, uterus, fetus if present, and bladder), testes, and thyroid glands. The kidneys, thyroid glands, testes, and liver were collected and put on snow or ice for up to 12 hours until they could be frozen. Kidneys with attached fat were wrapped in aluminum foil and placed in a plastic bag for subsequent contaminant analyses.
All caribou, with the exception of one adult, were aged either by size (calf, immature) (n = 4) or by cementum annular count of the primary (middle) incisor (n = 22) (Matson's Laboratory, Milltown, Montana, USA).
After examination and sample collection were complete, all caribou were taken back to the communities for distribution, while study samples were frozen at -20[degrees]C and transported to the AVC for further examination and sampling.
At the AVC, the...
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