Publisher's Synopsis
Many marine mammals communicate by emitting sounds that pass through water. Such sounds can be received across great distances and can influence the behavior of these undersea creatures. A low level sound can be audible to animals without resulting in any visible effect. At increased levels the sound may disturb animals and induce avoidance and other behavioral changes. If animals for any reason can't avoid a noise source, they may be exposed to acoustic conditions capable of producing negative effects, which may range from discomfort and stress to physical acoustic trauma. Exposure to very loud sounds, explosions at short range for example, can produce damage to many organs in addition to hearing. In the past few decades, the oceans have become increasingly noisy, as underwater sounds from propellers, sonars, and other human activities make it difficult for marine mammals to communicate. Human activities are increasing the level of sound in the oceans, causing widespread concern about potential effects on marine mammals and marine ecosystems. Major human sources of sound include seismic surveys for oil and gas exploration and scientific research; commercial shipping for transportation of goods; and sonar systems for military purposes, fishing, and research. Sound also is important to marine mammals for communication, individual recognition, predator avoidance, prey capture, orientation, navigation, mate selection, and mother-offspring bonding. Potential effects of anthropogenic sounds on marine mammals include physical injury, physiological dysfunction (for example, temporary or permanent loss of hearing sensitivity), behavioral modification (for example, changes in foraging or habitat-use patterns, separation of mother-calf pairs), and masking (that is, inability to detect important sounds due to increased background noise). For individual animals, such effects and their secondary consequences may vary in significance from negligible to fatal-the worst outcome being documented in a small number of cases. But over the last 100 years or so, increasing levels of anthropogenic noise from shipping, oil and gas exploration, naval sonar training, construction, and other activities have begun to drown out the ocean's natural sound. For whales, dolphins, and other marine life, this has resulted in a myriad of impacts, including stress, deafness, avoidance behaviors that have diminished feeding opportunities, and even death. Important progress has been made toward understanding sound and its potential effects on marine mammals. Clearly, the growing amount of human-caused noise in the ocean may be a growing problem for sound-sensitive creatures. Marine mammals and other marine species can suffer not only hearing damage when exposed to loud noises, but also other physical and psychological harm. This book named with Marine Mammals and Noise discusses how well marine mammals hear, how noisy the oceans have become, and what effects these new sounds have on marine mammals. The baseline of ambient noise, the sounds produced by machines and mammals, the sensitivity of marine mammal hearing, and the reactions of marine mammals are also examined. The challenge facing the concerned community of decision-makers, managers, scientists, sound producers, and conservationists is to gain an understanding of the effects of sound in the oceans and to manage those effects in a judicious manner. Doing so will require recognition of remaining uncertainties and provision of a suitable buffer to ensure marine mammal conservation, while also endeavoring to avoid or minimize unnecessary constraints on human activities that introduce sound into the oceans. Many marine mammals communicate by emitting sounds that pass through water. Such sounds can be received across great distances and can influence the behavior of these undersea creatures. A low level sound can be audible to animals without resulting in any visible effect. At increased levels the sound may disturb animals and induce avoidance and other behavioral changes. If animals for any reason can't avoid a noise source, they may be exposed to acoustic conditions capable of producing negative effects, which may range from discomfort and stress to physical acoustic trauma. Exposure to very loud sounds, explosions at short range for example, can produce damage to many organs in addition to hearing. In the past few decades, the oceans have become increasingly noisy, as underwater sounds from propellers, sonars, and other human activities make it difficult for marine mammals to communicate. Human activities are increasing the level of sound in the oceans, causing widespread concern about potential effects on marine mammals and marine ecosystems. Major human sources of sound include seismic surveys for oil and gas exploration and scientific research; commercial shipping for transportation of goods; and sonar systems for military purposes, fishing, and research. Sound also is important to marine mammals for communication, individual recognition, predator avoidance, prey capture, orientation, navigation, mate selection, and mother-offspring bonding. Potential effects of anthropogenic sounds on marine mammals include physical injury, physiological dysfunction (for example, temporary or permanent loss of hearing sensitivity), behavioral modification (for example, changes in foraging or habitat-use patterns, separation of mother-calf pairs), and masking (that is, inability to detect important sounds due to increased background noise). For individual animals, such effects and their secondary consequences may vary in significance from negligible to fatal-the worst outcome being documented in a small number of cases. But over the last 100 years or so, increasing levels of anthropogenic noise from shipping, oil and gas exploration, naval sonar training, construction, and other activities have begun to drown out the ocean's natural sound. For whales, dolphins, and other marine life, this has resulted in a myriad of impacts, including stress, deafness, avoidance behaviors that have diminished feeding opportunities, and even death. Important progress has been made toward understanding sound and its potential effects on marine mammals. Clearly, the growing amount of human-caused noise in the ocean may be a growing problem for sound-sensitive creatures. Marine mammals and other marine species can suffer not only hearing damage when exposed to loud noises, but also other physical and psychological harm. This book named with Marine Mammals and Noise discusses how well marine mammals hear, how noisy the oceans have become, and what effects these new sounds have on marine mammals. The baseline of ambient noise, the sounds produced by machines and mammals, the sensitivity of marine mammal hearing, and the reactions of marine mammals are also examined. The challenge facing the concerned community of decision-makers, managers, scientists, sound producers, and conservationists is to gain an understanding of the effects of sound in the oceans and to manage those effects in a judicious manner. Doing so will require recognition of remaining uncertainties and provision of a suitable buffer to ensure marine mammal conservation, while also endeavoring to avoid or minimize unnecessary constraints on human activities that introduce sound into the oceans. Many marine mammals communicate by emitting sounds that pass through water. Such sounds can be received across great distances and can influence the behavior of these undersea creatures. A low level sound can be audible to animals without resulting in any visible effect. At increased levels the sound may disturb animals and induce avoidance and other behavioral changes. If animals for any reason can't avoid a noise source, they may be exposed to acoustic conditions capable of producing negative effects, which may range from discomfort and stress to physical acoustic trauma. Exposure to very loud sounds, explosions at short range for example, can produce damage to many organs in addition to hearing. In the past few decades, the oceans have become increasingly noisy, as underwater sounds from propellers, sonars, and other human activities make it difficult for marine mammals to communicate. Human activities are increasing the level of sound in the oceans, causing widespread concern about potential effects on marine mammals and marine ecosystems. Major human sources of sound include seismic surveys for oil and gas exploration and scientific research; commercial shipping for transportation of goods; and sonar systems for military purposes, fishing, and research. Sound also is important to marine mammals for communication, individual recognition, predator avoidance, prey capture, orientation, navigation, mate selection, and mother-offspring bonding. Potential effects of anthropogenic sounds on marine mammals include physical injury, physiological dysfunction (for example, temporary or permanent loss of hearing sensitivity), behavioral modification (for example, changes in foraging or habitat-use patterns, separation of mother-calf pairs), and masking (that is, inability to detect important sounds due to increased background noise). For individual animals, such effects and their secondary consequences may vary in significance from negligible to fatal-the worst outcome being documented in a small number of cases. But over the last 100 years or so, increasing levels of anthropogenic noise from shipping, oil and gas exploration, naval sonar training, construction, and other activities have begun to drown out the ocean's natural sound. For whales, dolphins, and other marine life, this has resulted in a myriad of impacts, including stress, deafness, avoidance behaviors that have diminished feeding opportunities, and even death. Important progress has been made toward understanding sound and its potential effects on marine mammals. Clearly, the growing amount of human-caused noi
