TRACE ELEMENTS STATUS OF MOOSE AND WHITE-TAILED DEER IN NOVA SCOTIA

Abstract

The province of Nova Scotia is considered to have two distinct moose populations: mainland and Cape Breton Island. In 2003, moose of the mainland area of hte province were formally listed as "ENDANGERED" under the Nova Scotia Endangered Species Act. To date, the specific causes of the decline of this population have not been determined. Factors impacting health, including trace element imbalances, have been considered as potential limiting factors for the mainland population. Liver and kidney samples were collected from moose and white-tailed deer throughout Nova Scotia during the fall and winter 2000 – 2002 to compare trace element  concentrations between the two species, in relation to age, gender, and geographical location, and to other areas outside the province. All samples were analysed for arsenic, cadmium, cobalt, copper, lead, manganese, nickel, selenium, and zinc. Tissue concentrations of tace elements in deer and moose in Nova Scotia are generally similar to levels reported in cervid populations elsewhere in North America and Europe with the exception of zinc and cobalt, which appear to be lower in Nova Scotia. Kidney cadmium concentrations are high in some Nova Scotia moose (geometric mean = 60.4 μg/g dry weight, 95% CI = 40.3 – 90.6, n = 21), however, similar or higher concentrations have been reported in other regions. Relative to reference values for domestic cattle, cobalt, copper, manganese, selenium, and zinc levels are deficient or marginally deficient in some animals, however, there appears to be little supporting evidence that clinical deficiencies of any of these trace elements are occurring in Nova Scotia moose or deer populations. The possibility that marginal or deficient levels of these or other trace elements and high levels of cadmium may impact the health of individual animals either directly or through interactions with other factors (e.g., infectious and non-infectious diseases, harsh environmental conditions, habitat limitations) cannot be dismissed. Some considerations for continued monitoring of trace element concentrations in these populations are discussed.