Dolphin Tales: Injured dolphin in Pine Island Sound
While on tour this week, I spotted three bottlenose dolphins swimming together in Pine Island Sound. One of the dolphins had sustained a serious injury. The entire tip of the dorsal fin was cut off.
My onboard guests asked if I knew the injured dolphin. I had to say that I did not. I have seen many dolphins with compromised dorsal fins, but this dolphin seemed to have a fresh injury. It may have been a fresh injury to a dolphin I often see. Each dorsal fin is unique with its nicks and notches. Just as our scars have a story so do the dolphin’s scars. Scientists identify dolphins based on their dorsal fins which are similar to our fingerprints.
It was a teaching moment with my onboard guests as I explained about boat propeller strikes and entanglement in monofilament line. I also expressed that I am encouraged when I see these injured dolphins in the company of other dolphins. When I saw the three dolphins riding together, it occurred to me that they were swimming with the injured dolphin between them. Perhaps they were helping to stabilize their injured friend while swimming. Bottlenose dolphins are very communicative, cooperative and caring. Just as they are known to help humans in distress, they also help each other.
The dorsal fin is used for balance and to help the dolphin swim. It is like a boat’s keel helping the dolphin to stay stable. The curved shape of the dorsal fin also cuts through the water smoothly, creating less drag. Imagine if you lost the keel on your sailboat? The dorsal fin stops the body from rolling side to side or sliding sideways in the water. It helps the dolphin to turn fast without tipping over. While the tail flukes are the power that moves the dolphin, the pectoral fins help with steering. Tail flukes and pectoral fins can also sustain injury and cause lifelong challenges for dolphins.
Dorsal fins and pectoral fins are also crucial in the process of thermoregulation in the dolphins. In the extreme warm summer waters, dolphins are able to release heat through the dorsal fin, pectoral fins and the belly. This allows them to stay in our Southwest Florida waters year-round unlike the manatees who instinctively migrate to cooler waters.
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 (239) 994-2572. Welcome aboard!