The Importance of Monitoring Free-Ranging Pinnipeds and How It Relates to the Marine Ecosystem Health
1Colorado State Diagnostic Laboratory, College of Veterinary Medicine, Colorado State University, Fort Collins, CO, USA; 2The Marine Mammal Center, Golden Gate National Recreation Area, Sausalito, CA, USA
Since marine mammals are at the top of the food chain, studying them is an extremely important facet of any program to monitor the marine ecosystem. In order to monitor marine mammals one must have them in hand. There are two primary avenues of acquisition of these animals: you can go to them in the wild (field trips to find sick or dead animals) or you let the general public bring them to you (working with rehabilitation centers). Both are important and have advantages and disadvantages, but both avenues should be used to its maximum. Procedures use to monitor marine mammals both within rehabilitation centers and in the wild are similar. A complete physical examination should be done including collection of blood for blood cell counts and serology. Swabs of the nasal cavity and rectum should be taken for routine bacterial cultures. Feces should be collected for routine flotation examination for parasites. If the animal dies a complete necropsy should be done as quickly as possible, preferably immediately after the animal dies. Selected tissues should be collected and frozen and fixed in 10% neutral buffered formalin for histologic studies. Tissues saved for toxicologic analysis for organochlorines, polychlorinated biphenyls, and petroleum hydrocarbons should be wrapped in teflon. Tissues saved for trace minerals should be saved in plastic whirl packs. Tissues saved for virus isolation, micronutrients, biotoxins and various enzymes need to be preserved in liquid nitrogen. Liquid nitrogen dewars work well in the field for this task and can be taken on airplanes. Two examples that were found during a monitoring program of Northern fur seals that has a connection with the health of the marine ecosystem include entanglement of seals by orphan fish netting and packing bands and a condition called white muscle syndrome will be discussed.