Marine Toxins: Adverse Health Effects and Biomonitoring with Resident Coastal Dolphins

Abstract: Ecotoxicologic studies of marine environments are complex. Expanding knowledge should take into account toxicology, ecology, biology, medicine, and global as well as local anthropogenic disturbances of ecosystems. These areas of interest are discussed, leading to recommendations for biomonitoring of a specific location. Marine mammals are useful as bioindicators of environmental disturbance and as sentinels of health risks for humans who frequently consume seafood. A small community of bottlenose dolphins (Tursiops truncatus) in West Galveston Bay, Texas, with strong site fidelity is discussed here for consideration as a local environmental biomonitor. These dolphins are subject to a number of environmental impacts, including industrial toxins, nonpoint source agricultural and residential runoff, and pollutants from vessels. Other threats include climate change and toxic algal blooms. Marine mammal mass mortality events linked to morbillivirus infections in other areas have been associated with one or more of these environmental disturbances. Toxic effects described in cetacean literature generally do not include neurotoxic changes because specific tests for aquatic mammals are not yet available. Neurotoxicity has been addressed in studies of humans who consume contaminated seafood; specific findings are included in this review because marine mammals are likely to be subject to similar adverse effects. Researchers designing biomonitor studies need to keep in mind the multiple and complex impacts caused by both local and global issues. Known impacts on Galveston Bay are outlined and considered in suggesting local biomonitor study designs. Small populations of near-shore resident dolphins can serve more effectively as useful upper trophic level environmental bioindicators with such a multidisciplinary approach.


Document Type: Research article

DOI: 10.1578/AM.31.2.2005.195

Page Numbers: 195 – 225

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