Striped Dolphin

A pod of striped dolphins, which are uncommon in Andhra Pradesh's waters, was recently spotted off the coast of Visakhapatnam. This rare sighting has drawn attention from both local and international marine biologists, as striped dolphins are typically found in more temperate and tropical oceans but are not frequently seen in the coastal areas of Andhra Pradesh.

About the Striped Dolphin

Scientific Name: Stenella coeruleoalba
The striped dolphin is a streamlined oceanic dolphin that shares a similar shape and size to the common dolphin. Known for its distinctive physical features, it is one of the most abundant and widespread dolphin species in the world.

Distribution of Striped Dolphins

• Global Range:
  Striped dolphins are found in the temperate and tropical waters of all the world's oceans, from the Arctic to the Antarctic. Their range includes:

  • Waters off Greenland and Northern Europe (United Kingdom, Denmark)

  • The Mediterranean Sea

  • Japan, Argentina, South Africa, Western Australia, and New Zealand.

• Uncommon in Andhra Pradesh Waters:
  Although their global range is widespread, the sighting of striped dolphins off the coast of Visakhapatnam is notable as these dolphins are not commonly seen in Andhra Pradesh waters.

Habitat and Behavior

• Preferred Habitat:
  Striped dolphins prefer deeper, offshore waters over the continental shelves. They are often found in areas where upwelling occurs, where cold, nutrient-rich water rises toward the surface. These dolphins are also attracted to convergence zones, where different ocean currents meet.

• Social Structure:
  Striped dolphins are typically found in tight, cohesive groups, known as pods, which usually range in size from 25 to 100 individuals. They are social animals that display a wide range of playful behaviors, including breaching, jumping, and leaping as high as 20 feet above the water's surface.

Physical Features of the Striped Dolphin

• Size:
  Striped dolphins reach a length of 2.5 to 2.6 meters, with males being slightly larger. The average length is around 2.2-2.3 meters.

• Distinctive Features:

  • They have a long, defined rostrum (snout) and a round forehead (known as a melon).

  • Their dorsal fin is hooked, tall, and located mid-back.

  • The most recognizable feature of the striped dolphin is its stripes:

    • A dark grey stripe runs from the beak, above the eye, across the flank, and down to the underside of the body.

    • A second stripe runs below the eye to the pectoral flipper.

    • The dolphin’s flanks are light blue or grey above the stripes, with black appendages and a blue, white, or pink underside.

• Unique Behaviors:

  • The striped dolphin exhibits a behavior known as "roto-tailing", where it leaps out of the water and rotates its tail vigorously while airborne. This behavior is a rare and fascinating display of athleticism in marine mammals.

Lifespan and Conservation Status

• Lifespan:
  The estimated lifespan of striped dolphins is up to 58 years, which is relatively long for a marine mammal.

• Conservation Status:
  The striped dolphin is classified as "Least Concern" by the IUCN Red List, indicating that it is not currently at significant risk of extinction.