First Quarter Dolphin Overview

The 10,000 Islands Dolphin Study Project is the property of Dolphin Explorer LLC. The survey team on board the Dolphin Explorer monitors the daily activity of the local bottlenose dolphin population. Feeding habits, travel range, social behavior, association patterns, movement, distribution, genealogy and overall health of these cetaceans is recorded and has historical information dating over 18 years. The study continues…. 

What a great start to 2024 with our local dolphin population! The Fall of 2023 was really exciting with 10 new babies documented. This year could prove to be more eventful as the team identifies a potential 16 females that are eligible to give birth this coming Fall. Now, not all of these ladies will produce a new calf this year, but this could be a record year for births in the area! 

The gestation (pregnancy period) of our females is one year and with most births occurring in September, October and November. Several potential moms are now six months pregnant and beginning to show that widening girth in the midsection typical of a pregnant lady. 

Over the past 18 years the team has watched our moms have babies and those babies are now grown and having their own offspring. We are currently tracking nine grandmothers in the area waters. This Fall there is a potential for three new grandmothers here and, if all goes as hoped, we may have our first known  great grandmother! Yup…a fourth generation is just around the corner! 

There are some interesting goings-on in the male society as well. Since the first of the year, the team has seen several of our younger males that have recently reached maturity are challenging the older, more dominant, big boys for superiority in our dolphin kingdom. 

Of the 15 adult males in the area, six have ruled the mating game here for 15 to 20 years. As they get older, at least four younger males are looking the dominant boys in the eye. There could be a change in the hierarchy of the most fierce guys in the north Marco waters. This might take a year or two, maybe more, but change is imminent. 

The team experienced over 150 excursions in the first three months of 2024, with nearly 1,900 sightings of the 128 residential dolphins that call north Marco Island waters home. In addition to the residential, non-migratory dolphins we see throughout the year, there are transient dolphins, ones that just pass through here. The Marco River and Intracoastal Waterway are like I-75 for dolphins. These are the major “highways” they use for travel, and we have more than 100 non-residents that we see but are not identified since they are not residents seen all year long. 

Our ecosystem is very good. There is little to no industrial pollution around Marco to affect the marine health. Since the area waters, that being the river, bays, estuaries and channels, are so shallow, there are no large predators to reduce the dolphin population significantly. We find that the young of year, dolphins from birth to age three, are susceptible to predation by Bull sharks and Hammerheads but rarely bothered by sharks after the age of three. 

Dolphins not only become an apex predator when fully grown, they are also a “Keystone Indicator.” This means if the dolphins are doing well and staying put, the other marine life lower on the scale in our waters is also thriving. 

Yes, this is paradise for our dolphins as well as residents and visiting humans. 

Plenty of food, good environment and high on the pecking order, our bottlenose dolphin population has it made. How good is it? Well, the 128 dolphins that reside here will chow down one ton of fish per day, collectively! 

With a mix of 15 adult males and 39 adult females, the boys are not only in paradise, they are in heaven! 52 calves have been born in the last six years, with 43 surviving. That leaves another 30+ dolphins that will soon reach maturity. This is a great mix of ages and great ratio of males to females. 

One of the most important notes taken by the study team is that things are changing. Our entire crew is constantly learning. When we feel like a pattern has been established something happens to bend the rules. For example, the young males that are ready to change the dominance equation, the addition of up to three more grandmothers and the strong possibility that our first great-grandmother will be known. 

We are a young 18-year-old program, discovering new facts about our dolphin population constantly. We can’t wait to share what’s around the corner! Stay tuned! 

Bob is the lead Naturalist for the 10,000 Islands Dolphin Study Project. He is twice a national award-winning columnist for Coastal Breeze News, the author of two books and a regular speaker at area venues. The program has won several awards as well and distributes quarterly reports to colleges, universities and other dolphin study agencies. Bob loves his wife very much!