Quarterdeck Volume 6, Number 1, May 1998

GulfCet I Survey Results

• Visual Survey Results
• Acoustic Survey Results
• Aerial Survey Results
  
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Visual Survey Results

Based on the visual survey, there are at least
19, 128 cetaceans in the Gulf of Mexico

	Number of Sightings			Numbers Sighted
Selected cetaceans	70+	21-44	less than 20
Pantropical spotted dolphin	X			7,105
Bottlenose dolphin	X			2,538
Sperm whale	X			313
Risso's dolphin		X		519
Clymene dolphin		X		1,695
Dwarf sperm whale		X		53
Striped dolphin		X		2,091
Unidentified ziphiids			X	124
Melon-headed whales			X	2,067
Atlantic spotted dolphin			X	1,145
Spinner dolphin			X	840
Short-finned pilot whale			X	215
Killer whale			X	71
Pygmy killer whale			X	36
Rough-toothed dolphin			X	177

Range of group sizes
Smallest groups	Largest groups
Pygmy sperm whales	Melon-headed whales
Average of 1.2 animals/group	Average of 141 animals/group

Acoustic Survey Results

Acoustic contacts Daytime and good weather, Visual identification possible
	Sperm whale	273 (56% of total)
	Pantropical dolphin	22
	Twelve unidentified species	124
	Unidentified baleen whale (probably a sei or Bryde's whale)	1
	Unidentified cetaceans	30
	Unidentified bioloical contacts (probably shrimp)	19
	Total	469
Night, poor weather, No visual identification
	Unidentified dolphins	331

About the acoustic survey

• Acoustic sampling took place during 95% of the available time
• 1,055 hours of acoustic effort
• 12,219 kilometers surveyed
• Recordings were made of about half the species expected to occur in the gulf
• Recordings include the rarely recorded clymene and rough-toothed dolphins
• Recordings include first ever recording of a Fraser's dolphin
  
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Aerial Survey Results

Total of 8 aerial surveys for 49,960 total kilometers:

• 351 cetacean groups sighted
• 17 cetaean species identified
• Five species made up 71% of the sightings in which species were identified (each sighted 20 or more times:
  • Bottlenose dolphin
  • Pantropical dolphin
  • Risso's dolphin
  • Pygmy / dwarf sperm whales
  • Sperm whales

In each survey 5,330 - 6,592 kilometers were viewed

• Minimum sightings in asurvey: 24 (Fall 1992)
• Maximum sightings in a survey: 61 (Winter 1994)

In each season 11,756 - 12,942 kilometers were viewed:

Fall	Winter
Fewest sightings: 49	Most sightings: 109
Fewest species: 11	Most species: 15
Number of species identified in:
Four seasons - 8	Two seasons - 4
Three seasons - 2	One season - 4

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Last updated May 4, 1998