When we founded the 10,000 Island study way back in 2006, one of the things I wanted to determine was the range of the dolphins that lived around Marco Island and Naples – how far did they travel over the course of a day, a year, their entire life?

After processing almost 13,000 sightings of over 600 dolphins in which observers recorded where the dolphins were, who they were with and what they were doing, the answer turns out to be…

It depends on the dolphin.

You see, while it is possible with such a rich dataset to make all sorts of generalizations about the social life and ranging patterns of our local dolphins, it turns out the really fascinating insight is that dolphins are individuals. They exhibit a wide range of life strategies.

So, let’s answer the range question by looking at a few individuals.

ALEXANDRA ADULT MALE RANGE: > 31.62 MILES

Alexandra is a dolphin that has been on my mind because I recently received word that he had died and his body had been recovered by FWCC in Big Carlos Pass.

We first sighted Alexandra in 2006 in the intracoastal waterway about halfway between The Gordon River and Big Marco Pass. He and another male (PuzzleP) had formed a male alliance and would show up together in the intracoastal waterway and occasionally in Big Marco Pass but not very often and never as far as the Jolly Bridge.

I recorded him during some surveys up in Naples and that was probably the core of his range, with Marco Island the occasionally visited southern extreme. Based on his sighting history with The Dolphin Study and his location when recovered by FWCC Alexandra’s known range was about 32 miles though he probably extended somewhat further north. VIEW ALEXANDRA’S SIGHTING HISTORY

ALEXANDRA

SCOOP  

SCOOP       ADULT MALE           RANGE > 20 MILES

There were two other dolphins with Alexandra during that first sighting back in 2006 and, by some coincidence one of them, a male named Scoop, died within a few days of Alexandra. Scoop’s body was recovered a bit further south in Clam Pass.

In 57 of 59 sightings Scoop was with his male alliance partner Jingle – they were tight. We would see them around Marco Island regularly but not frequently and never much further south than the Jolly Bridge.

Like Alexandra, the center of his range was Naples and north. Based on his sighting history and his location when recovered by FWCC, Scoop’s known range was 20 miles though, like Alexandra, he probably ventured further north. VIEW SCOOP’S SIGHTING HISTORY

SKIPPER      ADULT FEMALE        RANGE:   8 MILES

We first saw Skipper a few days after her birth in September 2013. She was at the seawall on the northern side of the Isles of Capri with her mother Halfway. Halfway had frequented that seawall for years, often using it as a barrier against which to trap fish.

Skipper, now just over eight years old and a mother herself has never been sighted more than five miles from that seawall in either direction. Most of her 518 recorded sightings are clustered in Capri Pass and Big Marco pass. Given the frequency and consistency of her sightings that is probably an accurate reflection of her full range. You can learn more about Skipper’s home range and her social life here.

VIEW SKIPPER’S SIGHTING HISTORY

SKIPPER

HALFWAY

HALFWAY         ADULT FEMALE        RANGE:  11.25

Skipper’s mom doesn’t seem to have travelled much further in her life. Through 16 years and birthing 6 calves she has not been sighted outside of 11.25-mile area. She has never appeared in any of the over 150 surveys we have conducted over in Goodland on the Southern end of Marco Island with Dolphin Research Tours so I am fairly certain her range does not extend there. The clustering of her sightings suggests her range does not extend to Naples. Halfway seems content to satisfy all of her needs in the immediate vicinity of Big Marco Pass. VIEW HALFWAY’S SIGHTING HISTORY.

Two females whose range does extend from Naples to Goodland are Sydney and her daughter (now a mother herself) JingJing. Sydney and JingJing occurred frequently in sightings around Big Marco Pass suggesting the northern end of Marco Island is an important part of their range.

Our partner Dolphin Research Tours has conducted 175 surveys on the southern end of Marco Island in 2021 and both dolphins showed up there fairly regularly as well. Neither of them happened to be caring for calves in 2021 and they spent much of the year traveling together. As we expand our surveys further north and south, we may find the range of these two mothers is somewhat greater than 17 miles. VIEW SYDNEY’S SIGHTING HISTORY. VIEW JINGJING’S SIGHTING HISTORY

SYDNEY & JINGJING

COCKATOO

COCKATOO      ADULT MALE      RANGE: ~120 MILES

Just when you think you can start making some generalizations… Cockatoo occurs in only three sightings in The Dolphin Study database, once in 2006, again in 2007 (both in The Big Marco Pass) and then not until 2018 when I photographed him at the Naples Pier.

BUT – I’m not the only one recording dolphin sightings. Carolyn Cush curates the Gulf of Mexico Dolphin Identification System (GoMDIS) which brings under one umbrella dolphin i.d. catalogues from throughout the gulf. In one such catalogue she found a match to Cockatoo. Twice In 2005, The Eckerd College Dolphin Project had photographed Cockatoo in Tampa Bay over 120 miles from Marco Island!

It seems that Cockatoo had shifted his range to the south sometime after those 2005 sightings because he was rescued from an entanglement in a crab trap line by the FWCC in 2010 off Naples.

From Skipper’s limited range of less than ten miles to Cockatoo’s 120 mile journey from Tampa to Naples, the dolphins of Southwest Florida exhibit a variety of ranging patterns. The home range of most of the dolphins in The Dolphin Study database appear to be less than 30 miles with much of their time spent in an even smaller core area. You can view the sighting history of all of the local dolphins at The Dolphin Study. Our partner Dolphin Research Tours will continue to conduct surveys from Naples to Everglades City and we will certainly arrive at a more complete picture of each dolphin’s home range.