Texas Gulf Coast Fishing

Bottlenose Dolphin

BOTTLENOSE DOLPHIN Tursiops truncatus

Description: The bottlenose dolphin is one of the most well known species of marine mammals. They are grey, varying from dark grey at the top near the dorsal fin to very light grey and almost white at the underside. This countershading makes it hard to see, both from above and below, when swimming. Adults range in length between 6 and 13 ft. and in weight between 330 and 1,400 lbs. Males are on average slightly longer and considerably heavier than females. In most parts of the world, the adult's length is about 8 ft, with weight ranges between 440 and 660 lbs. Bottlenose dolphins may be seen in groups numbering up to several hundred but smaller social units of two to 15 are more common. Group size is affected by habitat structure and tends to increase with water depth. Group members interact closely and are highly cooperative in feeding, protective, and nursery activities. These dolphins make numerous sounds and are probably both good echolocators and highly communicative.

Distribution: Bottlenose dolphins are distributed worldwide in tropical and temperate waters. In the western North Atlantic, these dolphins occur as far north as Nova Scotia but are most common in coastal waters from New England to Florida, the Gulf of Mexico, the Caribbean, and south to Venezuela. This is the most common cetacean of the Gulf of Mexico and along the Texas coast. Bottlenose dolphins are commonly seen in bays, estuaries, and ship channels. Two distinct forms may occur in the Gulf. These are inshore animals that inhabit shallow lagoons, bays, and inlets and oceanic, or offshore, populations that remain in deeper, offshore waters. Interaction between the two populations is thought to be minimal.
Feeding Habits: Bottlenose dolphins eat a wide variety of food items depending on what is available and abundant at a given time. In Texas waters they eat fishes including tarpon, sailfish, sharks, speckled trout, pike, rays, mullet, and catfish. They are also known to eat anchovies, menhaden, minnows, shrimp, and eel. Commonly observed feeding behaviors include foraging around shrimp boats, either working or not, to feed on fish attracted to the boats. The dolphins also eat "bycatch" dumped from working trawlers. Groups of these dolphins have been observed cooperating in prey capture, with several dolphins herding fish into tight schools that are more easily exploited. Bottlenoses are also known to chase prey into very shallow water and may lunge onto mud banks and shoals in pursuit of panicked fish.