Hobbies And Interests
Background
Dolphins are large apex predators near the top of their food chain and they are long-lived. They are members of the whale family called odontocetes, or toothed whales, and are found in social groups that employ a diverse array of feeding tactics. They are efficient swimmers, reaching speeds of over 18 miles per hour, and can work together to encircle large schools of fish for feeding. Dolphins track their prey through echolocation, making up to 1,000 clicking noises per second. These sounds travel underwater until they encounter objects, then bounce back to reveal the location, size, and shape of their target. They can also use echolocation to detect prey under the sand. Main sources of prey include a wide variety of fish, squid, and occasionally, shrimp, small rays and sharks.
Ecological Balance
One of the important roles dolphins play in their ecosystem is as a predator that keeps prey numbers in balance. Without top predators like dolphins and sharks, certain prey species would go unchecked and can explode in numbers with harmful effects on the rest of the food chain. For example, an extermination of many great sharks along the eastern seaboard caused an increase in rays and the collapse of a century-old scallop fishery. Both dolphin and shark numbers have been threatened with the increase of net fishing that inadvertently tangles and kills these top predators. If ecosystems are truly ruled from the top, the collapse of the scallop industry could be a sign of things to come as predator populations crash worldwide.
Ecological Monitoring
Both dolphins and humans are mammals, and consume many of the same seafoods. In the ocean, dolphins are often exposed to toxic algae during ̶0;blooms,̶1; or red tide events. These toxins can also be taken in by shellfish and consumed by humans. Symptoms include paralysis, memory loss, brain damage, and even death in humans and marine mammals. Currently, there is no widespread, effective monitoring for the prediction of toxic algal blooms, which according to NOAA̵7;s Northwest Fisheries Science Center, are on the rise due to global warming. Along with natural toxins, dolphins have been known to concentrate high levels of man-made pollutants and heavy metals from their prey, and the levels of the contaminants in their bodies can indicate the health of ocean environments and a possible threat to human health. The Institute for Marine Mammal Studies suggests that monitoring dolphins that live in coastal areas not only protects marine animals, but humans as well.
Ecological Research
Although scientists are still clarifying the potential usefulness of large predator vertebrates, such as dolphins, to indicate ecosystem biodiversity, they are often used to indicate the health of prey species within their ecosystem. Top predators are useful indicators of marine ecosystem health because they depend on linkages throughout the food web. Examining a dolphin̵7;s diet can tell researchers a lot about the available resources in its environment. Most importantly, the conservation of dolphin habitat can act as an ̶0;umbrella̶1; for the conservation of other animals in the same ecosystem and promote sustainable management of fisheries, according to the South African Institute for Aquatic Biodiversity.