Meeting Abstract
The tracking of marine mammals with electronic devices enables researchers to gain a better understanding of their movements and at-sea behavior. In pinnipeds (seals and sea lions), electronic instruments are typically glued to the animal’s fur, either directly to the pelage or on a neoprene patch. When instruments are recovered for data collection they are retrieved either by cutting the fur or by cutting through the neoprene patch and leaving a layer of neoprene attached to the animal. The impact of these modifications to the animal’s pelage is presumed to be minimal, but this has not been explicitly investigated. This study examined the effects of instrument attachment and removal on the pelts of northern fur seals. Northern fur seals rely primarily on their fur for insulation in water and are thus ideal for determining the impacts of instrumentation on pelage function. To assess the extent to which water is able to penetrate the air layer of fur seal pelts during diving, we measured the volume of air released under hydrostatic pressure. Dives to 120m were simulated in a hyperbaric chamber for (a) unmodified pelts, (b) pelts with the top layer of fur cut, and (c) pelts with a layer of neoprene attached. We also measured the thermal conductivity of unmodified and modified pelts for both instrumentation methods. Cutting the fur during tag removal allowed water to penetrate the fur under pressure and reduced the thermal function of the pelt in water. In contrast, a neoprene patch better maintained the air layer and the insulation. This is the first study to measure the thermal consequences of instrumentation in fur seals and the results suggest that the use of neoprene in instrument attachment may minimize those consequences.
