Whale Shark Invasion & Encounters

In August 2009, we had what some have called an invasion of whale sharks off the Alabama/Florida coastline. During the month, over 60 sightings were reported to the Gulf Coast Research Laboratory Whale Shark Sighting Survey. The majority of the reports were between 5 and 10 miles of the beach and ranged from 1 to 25 sharks at each location. Many submissions were from scuba divers, who also submitted their photographs for photo-identification. One report was submitted by a kayaker, who was able to paddle his kayak one to two miles offshore to take a closer look at the magnificent shark. Due to the public support of whale shark research and the aid of the Ecocean photo-identification library (www.whaleshark.org), this summer marked the first time whale shark movement has been documented between the northern Gulf of Mexico and the Caribbean.

Map of whale shark sightings along the Alabama/Florida Gulf coast during the summer of 2009

Map of whale shark sightings along the Alabama/Florida Gulf coast during the summer of 2009

Chas Broughton of Underwater Works, local dive shop owner, called Dr. Hoffmayer to report a recent whale shark sighting and to offer to take us out to encounter these sharks. The first trip on Chas’ boat Gunslinger, named after his spear-fishing hobby, was eventful. Mobile Press-Register reporter Ben Raines was onboard in hopes of developing a good story and a spotter plane was in the air. Although the plane sighted a whale shark, the animal was gone by the time we reached the coordinates. Field studies can be extremely difficult and this day was an example; conditions seemed perfect but the animals were just not cooperating.

On August 10th however, our determination paid off. This time, GCRL scientists departed from Pensacola, Florida aboard the F/V Outcast, owned by Tommy Holmes.

View from the sight tower aboard the F/V Outcast, owned by Tommy Holmes

View from the sight tower aboard the F/V Outcast, owned by Tommy Holmes

 

USM-GCRL Shark Lab crew: Dr. Eric Hoffmayer, Jill Hendon, and Jennifer McKinney

USM-GCRL Shark Lab crew: Dr. Eric Hoffmayer, Jill Hendon, and Jennifer McKinney

The Outcast has a two-story tuna tower, which is usually used for cobia sight-fishing. On this day, it was particularly useful since we were unable to book a spotter plane. The tower provided a great vantage point and field view for shark watching. After a few hours of searching, a solitary whale shark was spotted. This juvenile shark made our jobs difficult by continually swimming into the murky depths, but since the water was only 50 feet deep it would soon resurface. We successfully attached a satellite tag to the animal and obtained identification photographs, a DNA sample, and other physical data from the animal.

Photo displaying the proper placement of the satellite tag at the base of the dorsal fin of a whale shark

The proper placement of the satellite tag at the base of the dorsal fin of a whale shark

Our presence did not seem to bother the shark and it stayed in the area for approximately an hour. Being able to pause and enjoy the majestic beauty of these animals was a special treat for the research crew, especially after the disappointment of failed attempts earlier that month.

Whale sharks act as fish habitat and are often found amongst schools of other fish, as seen here with popular sport fish Cobia (Rachycentron canadu)

Whale sharks act as fish habitat and are often found amongst schools of other fish, as seen here
with popular sport fish Cobia (Rachycentron canadu)

Whale shark swimming at the surface

Whale shark swimming at the surface

Many thanks to Chas Broughton of Underwater Works and Tommy Holmes of Outcast Fishing and Hunting for their generosity in donating their boat services and their valuable time to support our research.