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Marine Mammal Surveys

Clymene Dolphin
Photo Credit: SEFSC


Sperm Whales
Photo Credit: SEFSC

Mission: To assess the stock structure, distribution and abundance of marine mammals in the U.S. Atlantic, Gulf of Mexico, and Caribbean Sea.

A variety of surveys are conducted to accomplish its mission

• The large-scale surveys utilize ships and aircraft.
  • Visual sampling
  • Passive Acoustic Monitoring
  • Sperm whale dive interval protocol
  • Biopsy sampling
• Smaller scale surveys utilize small vessels.
  • Photographic Identification
  • Biopsy sampling

Visual sampling

Line Transect Survey
Photo Credit: SEFSC


NOAA Ship Gordon Gunter
Photo Credit: SEFSC

During broadscale visual line-transect surveys, visual surveys are conducted from the ship's flying bridge. On the flying bridge, observers are stationed at the port and starboard 25 x "bigeye" binoculars and the third observer watches the trackline with naked eye and small binoculars, and enters data into a laptop computer.

Passive Acoustic Monitoring

Acoustic line-transect surveys are conducted at night and simultaneously with the visual observations during the day. Acoustic monitoring is conducted using one of two towed hydrophone arrays:

1. A hand-deployed two-element hydrophone array is towed 200 m behind the ship
2. A five-element hydrophone array is towed up to 600 m behind the ship

Acoustic Monitoring
Photo Credit: SEFSC

The arrays are interfaced with a suite of electronics and scientists monitor the arrays. One use of the acoustic arrays is to track sperm whales.

Sperm whale dive interval protocol

When sperm whales are sighted the ship slows and a 90-minute observation period is conducted in order to obtain a more accurate group size estimate. Sperm whales typically dive for about 40-50 minutes and typically surface at least once during the 90-minute observation periods.

Sperm Whales
Photo Credit: SEFSC
Sperm Whale
Photo Credit: SEFSC

Biopsy Sampling

A variety of biopsy rifles, crossbows, and dart heads are used for collecting tissue samples from a small boat or from the ship's bow.

Bryde's Whale with Biopsy Dart
Photo Credit: SEFSC

Photographic Identification

Dolphin Photo ID
Photo Credit: SEFSC

Photographs of dolphin dorsal fins are taken and loaded into a FinBase database. The photographs are compared using natural marking on the trailing edge of the dorsal fin. Dorsal fins have been found to change very little over time and distinctive fins can be used to identify individuals.

Dorsal Fin (a)
Photo Credit: SEFSC
Dorsal Fin (b)
Photo Credit: SEFSC

Dorsal Fin (c)
Photo Credit: SEFSC
Dorsal Fin (d)
Photo Credit: SEFSC