threshold shift threshold shiftan increase (worsening) in the threshold of hearing for an ear at a specified frequencyRelated Articles: Hot Topic - Guidance on Determining Potential Effects to Marine Mammal HearingReference List: Animals and SoundHearing Loss in MammalsHearing Loss in FishesHearing Loss Advanced TopicHow is sound used to protect marine mammals?Tutorial: Mammals - Hearing lossSound Pressure Levels and Sound Exposure LevelsTutorial: Hearing LossSeismic Airguns Chris Knowlton2017-02-26T20:10:02-05:00