Research Highlights 5 Houser2019

Are Marine Mammal Pools Too Loud?

A collaborative effort was undertaken to measure underwater noise levels in a variety of marine mammal facilities, including land-based pools, semi-natural enclosures, and coastal habitats. The levels measured in pools were generally similar to those in natural coastal environments, with a relatively low presence of noise generated by humans or machinery. What noise existed in land-based pools was primarily due to the operation of water treatment/filtration systems and was at sound frequencies below the animals’ best range of hearing. Noise levels at higher frequencies in land-based pools were comparable or even lower than in semi-natural and natural systems, because of the presence of biological noise sources in the latter (e.g. snapping shrimp). For dolphin enclosures, the animals themselves were often the greatest source of sound at frequencies where they have their best hearing. The potential for facility ambient noise to acoustically mask communication signals and echolocation clicks appears to be low. Occasional noise issues were found, and so it is recommended that facilities periodically assess enclosure noise conditions to optimize animal management and welfare.


  • Houser, D. S., Mulsow, J., Branstetter, B., Moore, P. W. B., Finneran, J. J. & Xitco, M. J. Jr. (2019). The characterization of underwater noise at facilities holding marine mammals. Animal Welfare, 28, 143-155.

Affiliate Organizations:  National Marine Mammal Foundation, U.S. Navy Marine Mammal Program, Aquatica, Brookfield Zoo, Dolphin Connection, Discovery Cove, Dolphin Quest, Georgia Aquarium, Marineland Dolphin Adventure, Miami Seaquarium, Mirage, National Aquarium, Resorts World Sentosa, SeaWorld, Shedd Aquarium, Theater of the Sea

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