![]() ![]() The National Marine Mammal Foundation (NMMF) in collaboration with the Norwegian Defense Research Establishment (FFI) is undertaking an effort to acquire the first audiogram (hearing sensitivity curve) for a baleen whale. As a result, the SOST Interagency Task Force on Ocean Noise and Marine Life has identified a lack of knowledge about baleen whale hearing as a critical impediment to protecting baleen whales from ocean noise. Importantly, no test of the frequencies that baleen whales can hear has ever been successfully performed, and the hearing abilities of baleen whales have only been estimated from ear anatomy and observed behavioral responses to sound exposure. This knowledge ultimately helps in the development of measures to protect the whales from ocean noise. Understanding what a whale can hear is the first step in determining what kinds of anthropogenic ocean noise might affect them. As many baleen whales are endangered and their rates of producing calves are low, there is reasonable concern as to how anthropogenic noise might affect baleen whales and their populations.Īnthropogenic ocean noise covers a broad range of frequencies (i.e., from low to high pitches) whales might not be able to hear some of these frequencies of sound, but other sounds might occur at frequencies to which whales are very sensitive. ![]() In short, anthropogenic sound is noise to baleen whales and it has the potential to negatively affect them. It can potentially hinder a baleen whale’s ability to hear and avoid ships, and chronically high levels of sound might elevate levels of stress hormones that affect a whale’s health and ability to reproduce. Anthropogenic sound can potentially affect a baleen whale’s hearing, change its behavior, and interfere with its ability to communicate, forage, and navigate. Baleen whales rely on sound to communicate, forage, and navigate the world’s oceans. These whales filter feed using baleen, which is a feathery, filter-like comb structure within the mouths of the whales. Baleen whales, otherwise called mysticete whales, are the largest animals on earth. Because sound travels efficiently through water, sounds produced in the ocean can travel great distances and can be detected thousands of miles away from the source of the sound if the sound is of a sufficiently high level. A dramatic increase in the use of cargo ships for transporting commercial goods and a proliferation of recreational vessels have also contributed to an increase in ocean sound in many parts of the world. Human-made sound, or anthropogenic sound, is intentionally used to explore the ocean floor, to search for oil, in scientific research, in fisheries, and for military purposes (e.g. Currently this species is classified as Data Deficient (DD) on the IUCN Red List.Over the last century, humans have increasingly put sound into the ocean. Population numberĪccording to the International Whaling Commission's most recent estimate in 2003-2004, the population size of Antarctic minke whales is around 515,000 individuals. ![]() There will be increased competition for food and space as the extent of prey populations and suitable habitat reduces, with the result that this whale population will decrease. With rising temperatures, the reduction of sea ice suggests a loss of 5 - 30 percent over the next 40 years of ice-associated habitat, which may also affect Antarctic krill abundance. Climate change is another possible major threat. Antarctic minke whales, like all cetaceans, are also vulnerable to noise and chemical pollution. Scientific and commercial whaling are major threats for the Antarctic minke whale, and it is now a main target of the whaling industry in Japan, especially as larger species of whale have been depleted through hunting. ![]()
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