Dolphin Tales: Dolphins’ diving duration and depth
I often have onboard guests asking how long a bottlenose dolphin can hold its breath. They are also curious as to how deep a dolphin can dive. I explain to them that the water is very shallow in Pine Island Sound. Most of the water is less than 5 feet deep and perhaps in the navigational channels it is 9-12 feet deep. Because our waters are very shallow, the dolphins are not diving as deep as offshore dolphins therefore not holding their breath as long.
Because coastal and inshore dolphins live in bays, estuaries and shallow coastal waters, their dives are typically much shorter and shallower. Their dives average only 20 to 40 seconds in duration and rarely exceed 9 to 30 feet in depth. In our back bays, you will see them foraging for fish on the shallows where their bellies are literally rubbing the sandy bottom. When you enter the channel in Charlotte Harbor headed to Boca Grande, you begin seeing depths of up to 30 feet. When you are near the passes leading to the Gulf, depths will reach 60 feet or more.
Bottlenose dolphins can typically hold their breath for 8 to 10 minutes. However, during normal daily activities like swimming and hunting, they usually surface every 20 to 40 seconds. This is why we see them so frequently in our back bays and estuaries. They are eating and playing and they are close to the surface of the water.
Offshore dolphins regularly dive to depths exceeding 600 feet, with maximum recorded dives reaching a staggering 3,200 feet. These offshore populations are incredible deep divers as they hunt for deep water fish and squid. The maximum voluntary recorded breath-hold for a tagged offshore bottlenose dolphin is nearly 15 minutes.
Our bottlenose dolphins are highly intelligent. Most of their feeding strategies are specialized cooperative behaviors that have been passed down from their mothers. A great deal of the dolphin’s day is spent hunting for food. They typically hunt every 1.5 to 2 hours. Peaks in feeding occur at dawn, dusk and early afternoon. A lot of their hunting depends on localized prey movements. They consume 4% to 6% of their body weight in food daily. This is roughly 15-30 pounds of fish or squid for the average adult bottlenose dolphin.
Captain Cathy Eagle has spent over 45 years boating on our local waters. As a professional charter captain, she specializes in Dolphin and Nature Tours. You can reach her at CaptainCathy.com or call /text (39) 994-2572. Welcome aboard!