432
coastal marine mammals, but other more thorough resources are referenced for
in depth reviews of these more widely covered species.
Keywords Marine mammal · Sperm whale · Beaked whale · Dolphin · Passive
acoustic monitoring · PAM · Sea turtle · Loggerhead · Kemp’s ridley · Megafauna ·
Bottlenose · Barataria Bay · Mammal · Odontocete · Bryde’s whale · Spotted
dolphin · Stenella · Kogia · Echolocation · Visual survey · Nesting · Entanglement ·
Ship strike · Noise · Airgun · UME · Unusual mortality event · Leatherback,
Hawksbill · Stranding · Pinniped · HARP · Mississippi Canyon · Green Canyon ·
Sargassum · Green turtle · Trawl · Skimming · Risso’s dolphin · Pilot whale · Tag ·
Aerial survey · Bycatch
26.1 Megafauna of the Gulf of Mexico
The Gulf of Mexico (GOM) supports 5 species of sea turtles and at least 21 species
of marine mammals including 1 species of baleen whale, 19 species of toothed
whales, and 1 species of manatee (Darnell 2015). Gulf marine mammal species fall
into several ecological groups: Shallow-dwelling bottlenose dolphins (Tursiops
truncatus) inhabit coastal waters including bays, sounds, and estuaries, as well as
the broad continental shelf regions extending from the coast out to the shelf break.
Atlantic spotted dolphins (Stenella frontalis) are also commonly found on the continental shelf. The majority of the marine mammal diversity in the GOM is found at
or beyond the shelf break, often hundreds of kilometers offshore. Pelagic deepdiving species include sperm whales (Physeter macrocephalus), Gervais’ and
Cuvier’s beaked whales (Mesoplodon densirostris and Ziphius cavirostris), and
Kogia species, which execute long foraging dives to depths typically exceeding 200
meters. These species feed at depth, primarily on squid and do not typically exhibit
diel foraging patterns. At least 13 species of pelagic, shallower diving delphinids
(typical diving depths less than 200 m) are also found in the region. These species
feed nocturnally on vertically migrating mesopelagic prey in the deep scattering
layer. A single baleen whale species, the GOM Bryde’s (Balaenoptera edeni) whale,
is found in the northeastern GOM near Desoto Canyon (Soldevilla et al. 2017).
All marine mammal species currently known to the northern GOM are also
found in other oceans; however, little is known about the migration ranges of Gulf
populations or the degree to which they mix with populations in the southern GOM
and broader Atlantic. The GOM Bryde’s whale is thought to be a distinct and isolated subspecies (Rosel and Wilcox 2014). The GOM sperm whale population also
appears to be resident in the area (Waring et al. 2009; Jochens et al. 2008). Sperm
whale sightings in the GOM often consist of groups of females and juveniles; therefore, the region is thought to serve as a year-round nursing ground for sperm whales.
Large solitary males, which are routinely observed in other oceans, are rarely
encountered in the GOM, and tag data has shown that males may travel in and out
of the Gulf (Jochens et al. 2008).
K. E. Frasier et al.
coastal marine mammals, but other more thorough resources are referenced for
in depth reviews of these more widely covered species.
Keywords Marine mammal · Sperm whale · Beaked whale · Dolphin · Passive
acoustic monitoring · PAM · Sea turtle · Loggerhead · Kemp’s ridley · Megafauna ·
Bottlenose · Barataria Bay · Mammal · Odontocete · Bryde’s whale · Spotted
dolphin · Stenella · Kogia · Echolocation · Visual survey · Nesting · Entanglement ·
Ship strike · Noise · Airgun · UME · Unusual mortality event · Leatherback,
Hawksbill · Stranding · Pinniped · HARP · Mississippi Canyon · Green Canyon ·
Sargassum · Green turtle · Trawl · Skimming · Risso’s dolphin · Pilot whale · Tag ·
Aerial survey · Bycatch
26.1 Megafauna of the Gulf of Mexico
The Gulf of Mexico (GOM) supports 5 species of sea turtles and at least 21 species
of marine mammals including 1 species of baleen whale, 19 species of toothed
whales, and 1 species of manatee (Darnell 2015). Gulf marine mammal species fall
into several ecological groups: Shallow-dwelling bottlenose dolphins (Tursiops
truncatus) inhabit coastal waters including bays, sounds, and estuaries, as well as
the broad continental shelf regions extending from the coast out to the shelf break.
Atlantic spotted dolphins (Stenella frontalis) are also commonly found on the continental shelf. The majority of the marine mammal diversity in the GOM is found at
or beyond the shelf break, often hundreds of kilometers offshore. Pelagic deepdiving species include sperm whales (Physeter macrocephalus), Gervais’ and
Cuvier’s beaked whales (Mesoplodon densirostris and Ziphius cavirostris), and
Kogia species, which execute long foraging dives to depths typically exceeding 200
meters. These species feed at depth, primarily on squid and do not typically exhibit
diel foraging patterns. At least 13 species of pelagic, shallower diving delphinids
(typical diving depths less than 200 m) are also found in the region. These species
feed nocturnally on vertically migrating mesopelagic prey in the deep scattering
layer. A single baleen whale species, the GOM Bryde’s (Balaenoptera edeni) whale,
is found in the northeastern GOM near Desoto Canyon (Soldevilla et al. 2017).
All marine mammal species currently known to the northern GOM are also
found in other oceans; however, little is known about the migration ranges of Gulf
populations or the degree to which they mix with populations in the southern GOM
and broader Atlantic. The GOM Bryde’s whale is thought to be a distinct and isolated subspecies (Rosel and Wilcox 2014). The GOM sperm whale population also
appears to be resident in the area (Waring et al. 2009; Jochens et al. 2008). Sperm
whale sightings in the GOM often consist of groups of females and juveniles; therefore, the region is thought to serve as a year-round nursing ground for sperm whales.
Large solitary males, which are routinely observed in other oceans, are rarely
encountered in the GOM, and tag data has shown that males may travel in and out
of the Gulf (Jochens et al. 2008).
K. E. Frasier et al.