Atlantic Spotted Dolphin - Stenella frontalis

Atlantic Spotted Dolphin
Stenella frontalis

Other Names: Spotted Porpoise, Spotter, Bridled Dolphin, Gulf Stream Spotted Dolphin, Long-snouted Dolphin; formerly S. plagiodon (in eastern USA).

Habitat: Offshore and Inshore

Status: Locally common

Population: Unknown

Threats: Hunting/whaling and entanglement in fishing nets

Group Size: 5-15(1-50), a few hundred may form temporary gatherings

Fin Position: Center

Newborns: 32" to 4'(80cm-1.2m), weight unknown

Adults: 5'Ľ"-7'˝"(1.7m-2.3m), 220-310 lb.(100-140 kg)

Diet: Fish, squid or octopus, and occasionally other invertebrate

Teeth: 64-84 on top row, 60-80 on bottom row

Description

Dorsal fin:

- tall, falcate dorsal fin (variable)
- some fins curve distinctly backward
- strongly concave trailing edge
- pointed tip
- usually unspotted

Flukes:

- a slight notch in the middle
- flukes usually unspotted
- medium gray tail stock

Flippers:

- pointed tips
- curved flippers usually unspotted
- faint light gray band between eye and flipper
- moderately long, chunky beak tipped with white

Other characteristics:

- "lips" may be white
- fairly robust head and body
- dark purplish gray cape on upper side
- white underside always shows through spots
- dark spots cover light areas of body and remain distinctly defined
- band of medium gray along each side
- pale diagonal shoulder blaze (variable)
- light spots cover dark areas of body (some may appear white from a distance)

Older Animals:

- spots bigger and more numerous in older animals
- basic body pattern remains the same throughout animal's life
- spots remain distinctly defined
- dark spots may make some animals appear almost black on underside
- background color may be partly observed by extensive spotting

Newborn:

- no spots
- flippers darks than rest of body
- dark cape distinctly separate from lighter sides
- flukes have dark trailing edges

Behavior

- very active at the surface
- often breaches
- most aerial behavior is observed when feeding
- fast and energetic swimmer, using long, shallow leaps
- avid bow-rider
- frequent reports of mixed schools with Bottlenose Dolphins often leads to mistaken identity
- when surfacing, tip of the beak typically breaks the surface fist, followed by the head, back, and dorsal fin
- group size is generally smaller (5-15) in inshore populations
- social structure appears to be fairly complex and is believed to include individual recognition and bonding

Distribution

- warm temperate, subtropical, and tropical waters in both the north and south Atlantic
- gulf of Mexico population moves closer to shore during summer
- usually found over the offshore continental shelf.
- small, less spotted form more pelagic than larger, heavily spotted form

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu

Internet Coordinator: Candice Orca Mottet

e-mail questions, comments, and/or suggestions to wcrc@sci.tamucc.edu

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu