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It is interesting to note that the ancient Greeks worshiped the dolphin. Killing of dolphins was punishable by death in ancient Greek society. The people of ancient Crete believed dolphins were gods.


The natural predators of the dolphin are tiger sharks, great white sharks, and bull sharks as well as Orcas, commonly known as killer whales (although the Orca is really another species of marine dolphin). Generally, these predators prey on weak or injured dolphins. When a shark attacks a dolphin it will often tear off the flukes, disabling the animal and causing it to swim in circles, bleeding and exhausted. It then becomes an easy meal for the predator with little risk of fighting back. Dolphins tend to move out of areas in which sharks are abundant.

Sharks and orcas account for a number of dolphin kills each year, but far more dolphins are killed by man through destruction of the dolphin's habitat, incidental catch, and harassment of wild animals. 
Today, the Bottlenose is threatened by a number of factors. These include injury and death due to inappropriate fishing practices with gillnets, crab pots, shrimp trawling and seining. Long line fishing is also a major threat to this animal. Of these fishing practices, gillnetting causes the largest mortality in dolphin populations. 


Following commercial fishing vessels, dolphins are able to increase their opportunity to find tuna and other fish in high concentrations. When the gill nets and seines used by these vessels trap the desired schools of fish, they also trap the dolphins feeding on them. As dolphins must surface to breathe air, they will drown if they are not quickly released from these nets and seines.
Efforts by some major commercial fishing industries to avoid inadvertant capture of dolphins as "by-catch" (such as in tuna fishing) have helped to reduce the accidental killing of dolphins.



The Bottlenose is protected by the Marine Mammal Protection Act of 1972 and is listed by this organization as "depleted". The passing of this act is largely responsible for the designation of "Dolphin Safe" tuna (tuna caught without the netting of dolphins as by-catch). As a result, dolphin deaths due to inappropriate fishing practices have declined from over 5,000 in 1990 to 0 in 1996. As a result of this act, in 1991 the United Nations adopted a resolution very similar to the MMPA, establishing a global moratorium on the reduction of dolphin populations. This has been effective in reducing the dolphin death rate, particularly in the eastern Pacific Ocean.


Pollution, parasites, naturally occurring biological toxins, and viruses are also responsible for dolphin deaths.  63,000 chemicals are in use worldwide, many reaching our oceans. Materials such as pesticides and heavy metals are dangerous to the dolphin, concentrate in its blubber and enter the milk fed to its calves. The health of our oceans is crucial to man's survival and the dolphin may well serve as an "indicator species" of impending changes in our marine environment, both chemical and physical. Improvements in our environment may relate to changes researchers are able to observe in the lives of dolphins.
In July, 2009 is was reported that there are approximately 3,000 discarded and lost fishing nets underwater in Puget Sound, Washington. Some of these nets are as large as a football field. They continue to inadvertently snag marine wildlife, including dolphins. Unable to surface for air, these dolphins drown within a few minutes. As part of the federal economic stimulus package, $5 million has been provided to hire local divers to retrieve these nets, but months will be required to complete this important conservation effort.

NOAA (the National Oceanographic and Atmospheric Association) in March, 2009, issued an alert, warning of fines up to $20,000.00, imprisonment up to 1 year, and potential bite danger to humans when approaching, feeding or harassing dolphins. Intentional human contact with wild dolphins reduces their fear of people and can negatively alter their natural feeding instincts and reduce the ability of dolphin cows to teach their calves to hunt for food.
Since 2006 there has been a reported increase in dolphin deaths due to "depredatory" behavior. Depredation is when another aquatic animal steals an anglers' bait during recreational fishing. In Florida it is common for alligators, sharks and dolphins to do this. The waters off the coast of Florida support a great number of recreational anglers. Dolphins will attempt to steal bait or hooked sport fish from anglers' gear. The dolphin will become entangled in the fishing line or more often will swallow the fishing hook and attached monofilament line in the "stealing" process, causing injury or death to the dolphin. Oftentimes the injured dolphin will strand and die. Increased stranding due to depredatory behavior has been noted in the Indian River Lagoon and Southwest Florida areas the last 4 years. To date over the last 4 years, NOAA reports 13 Bottlenose dolphins have been found stranded due to such behavior in this area of Florida. Although this number may seem small, it is significant. The Atlantic Bottlenose stock in this area does not migrate and any loss of members is not replaced by new members immigrating to the Southwest Florida area.
What can you do? If you are fishing and see dolphins near your gear, retrieve your gear and move elsewhere to fish. Do not cast fishing gear near visible dolphins. If you hook a dolphin accidently, provide slack in the line to allow the dolphin to release itself. If this does not work, cut the line off as near the hook as possible to release the animal. Use hooks that are NOT stainless steel and will corrode, eventually dropping out of the dolphin's mouth. Do not release caught fish near an area inhabited by dolphins. That practice will attract more dolphins and will teach them they will be fed near fishing vessels. Avoid tossing overboard any leftover bait for the same reasons.
The International Whaling Commission is another organization founded to protect the future of, among other animals, the Bottlenose dolphin. Members of the IWC are asked to report inappropriate catching of dolphins, including the accidental entanglement of these animals in fishing gear.
The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) includes Bottlenose dolphins as a species which is threatened and likely to become endangered if it is not appropriately protected.

Some dolphin experts are becoming increasingly concerned over the "swim with" programs now so popular in certain parts of the world. They feel these programs may negatively alter the behavioral patterns of wild dolphins, causing them to become more dependent upon man for providing their food. Increased wild dolphin aggression may also occur as a result of these programs. A doubling in the rate of calf mortality has been observed in areas where wild dolphin populations are associated with these "swim with" programs.

Unfortunately, Japan, Taiwan, Peru and Sri Lanka continue to harvest dolphins for human consumption, leather, oil and fertilizer production, even though this is in violation of international law. Thousands of dolphins are taken each year in Japan for consumption. Although, according to the latest statistics, the numbers of dolphins being captured by the Japanese appears to be down, the majority of these captured animals are still being killed (as illustrated in the following graph). 


"Drive hunts", used by the Japanese to capture and/or kill dophins continue to occur (see the dramatic video below).

Site Content
Understanddolphins.com contains information condensed from a number of reputable technical sources, peer reviewed journal articles, and respected dolphin research facilities, as well as from my personal experiences and observations as a dolphin VIP Tour Guide and Educator.
I have made every attempt to support the information presented in this site with video and still photographic images. On a regular basis I plan to produce more of these images and will continue to update the site with these as well as with any new and scientifically verified information which becomes available.

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