Dolphin Demise

Captain Scott Smith has been studying the species Stenella Frontalis, the Atlantic Spotted dolphin for over 25 years. The statistics for 2005 are in and the numbers are frightening. Nearly 1/3 of the spotted dolphin population seems to have “disappeared”. Spotted dolphins are commonly recognized by their spots that develop as they age and are considered a near-shore species ranging in the tropical waters of the Atlantic.

The Little Bahama Bank, home of the spotted dolphin, is near major shipping routes that have been used since the Americas were “discovered”. This is where Captain Scott goes every year to identify the individuals, catalog behaviors and study these amazing mammals.

The country of the Bahamas lies just fifty miles from the south east coast of Florida. The Bahamas consist of more than 700 islands that stretch over 100 miles. These islands dot the edges of what is referred to as Banks, vast areas of shallow water, 10-30 feet deep. The edges of the Banks are lined with cays, rocks, reefs and wrecks which then drops off to water that is 200+ feet deep. The northern most of these is called the Little Bahama Bank. The 40-mile long western edge of the Little Bahama Bank is where the southern, central and northern groups of spotted dolphin call home. To the south is the island of Grand Bahama, the port of West End and along the edge are small cays. As you travel north you head into the wide-open Atlantic Ocean. Between Florida and the Bank runs a major ocean current called the Gulf Stream. The Gulf Stream moves vast amounts of water from south to north. This warm clear water, rich in life, is brought to the edge of the Banks providing an abundant food source to the dolphins as well as the other marine life. There is a sand bar on the Little Bahama Bank that is referred to as White Sand Ridge, it’s where most of the dolphins are found.

On average Captain Scott will see 60 resident dolphins throughout the year. His ID catalog has over 125 dolphins in it. Some are transient dolphins moving through the area that he may see only once every several years. He is very familiar with this population and it’s residents, many he can recognize by sight alone. Captain Scott reports, “My first indication that something was wrong came in the spring. We did not see the large groups of 30-40 dolphins that we normally see at that time of the year. We never saw groups of more than 10-12 dolphins. The residents have dropped in number to a shocking 47 and it’s not just older ones missing, dolphins of all ages went unseen this year. To even find those residents we had to travel 10 miles further north.” That may not seem far to travel, but for spotted dolphins recorded in the area since the 1700’s by salvage divers working the shallow waters of old sailing ship wrecks, that distance is staggering.

When asked why, Captain Scott replies, “has the demise of the spotted dolphin occurred from man, natural disasters, a shift in predator hunting grounds or all of the above? It’s yet to be determined.” Here are some of his observations.

With the Little Bahama Bank so close to Florida, its popularity as a great area to fish and dive grew during the 1960’s. During the Mid 70’s, salvage diver Robert Marx and his crew were looking for gold from an old Spanish Galleon. They would spend hours searching the bottom, while curious dolphins moved in and out of the area to see what they were up to. As the dolphins appeared, the divers would swim and interact with them. In 1979 Robert Marx starting spreading the word and by the late 1970’s and early 1980’s charter boats were running a few trips a year to swim with these very friendly, wild dolphins.

During the late 1980’s and the boom of the live-aboard dive/charter boats, word spread of these unbelievable encounters. More and more people wanted the experience of swimming with a wild dolphin. With each passing decade, as more and more people get their own boats the White Sand Ridge has become a very crowed area in the summer months.

Are these numbers of boats and people pushing the very dolphins they have come to enjoy out of the area? Dolphins like to swim at about 10 knots and have bursts of speeds up to 30mph. The super fast boats, like cigarette boats, can travel at such high speeds they can cause propeller damage to a dolphin unable to get out of the way quick enough.

Or is it the bottlenose dolphins, usually found farther south, but are now seen in abundance on the ridge? The bottlenose dolphin is more aggressive and much larger in size than the spotted dolphin; they may be “bullying” them out of the area.