Marine mammals are humans' closest connection to the ocean. We can identify closely with the eyes of a baby sea otter or the familial calls of a killer whale - but if we look closely, they tell us more about the ocean than we'd expect. "These are species that affect people; they're affected by people; and they also affect a lot of other organisms in the environment," said Dr. Kathy Frost, a marine mammal researcher from the University of Hawaii. "They prey on species that are important to us. We need to monitor sooner rather than later."
The biological portion of the PWSOS will include marine mammal monitoring. A consistent set of data about marine mammals has the potential to reveal to scientists much about the ecosystems that support them. According to Frost, PWS and the Gulf of Alaska (GOA) support some of the richest marine mammal fauna in the world: 21 species are currently known to live in these waters. Of these 21, four species - the harbor seal, the killer whale, the sea otter, and the stellar sea lion - would likely be the easiest and most useful to monitor.
Monitoring can be done in many ways. The classic way to monitor marine mammals is through personal observations. Scientists typically do yearly population counts, and for many species they will try to identify individuals, watch how many years they return to a certain site, and determine their survival rate. Satellite tagging can be an effective tool for monitoring many species. This small wire is attached to an area of an animal's body where it will not affect its daily life, and allows scientists to track the animal's movements in the water throughout the year. Satellite tagging can be combined with a mini-CTD (conductivity, temperature and depth measurement) that can be used to test the water content over an area as wide as the animal travels.
Recently, scientists have developed a way to monitor marine mammals that pass through a specific area by using acoustic monitoring devices. These devices are attached to buoys around the ocean and record the sounds made by mammals that pass in the vicinity. Based on the knowledge that individual mammals have distinct calls, the devices can record which animals are passing through at what times of the year. Many of these acoustic devices have already been placed around the Gulf of Alaska and the Aleutian Islands. "Even for people like me who are pretty skeptical, (they are) providing a remarkable amount of information," Frost said. "They're a low cost technological way to get information about species that we know very little about."
Currently, all four species that Frost says are of critical importance to PWS are either stable or increasing in number. For the seals, sea lions and sea otters, that stability comes following a drastic and dangerous population drop that had scientists across Alaska scrambling for a solution. Millions of dollars were poured into the restoration of sea lions with seemingly little effect. At the same time, sea otter populations fell drastically just after scientists thought they were thriving. These recovering mammals have taught scientists many lessons; among them, that money is no replacement for consistent monitoring and preventative action. The future of biological monitoring in PWS will allow scientists to know and understand better the causes for population changes, so that when a population begins to drop they can take more effective steps toward preserving the species.
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