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The Biology of Sea Turtles, Vol. II
clutches annually at 14-day intervals (Pritchard, 1969; Kalb, 1999), and may use
multiple, geographically distant beaches within a nesting season (Kalb, 1999). Arribada nesting females emerge onto beaches to lay eggs en masse at a few select
beaches in the Atlantic, Pacific, and Indian Oceans. The arribada nesters have strong
site fidelity (Plotkin et al., 1995; Kalb, 1999), lay two clutches approximately every
28 days (Pritchard, 1969; Kalb, 1999), and may delay nesting for 6–8 weeks when
environmental conditions are unfavorable (Plotkin et al., 1997). Once mating and
nesting is completed, olive ridleys quickly migrate back to oceanic waters.
The postreproductive migrations of olive ridleys are unique and complex. Their
migratory pathways vary annually (Plotkin, 1994), there is no spatial and temporal
overlap in migratory pathways among groups or cohorts of turtles (Plotkin et al.,
1994; 1995), and no apparent migration corridors exist. Unlike other marine turtles
that migrate from a breeding ground to a single feeding area, where they reside until
the next breeding season, olive ridleys are nomadic migrants that swim hundreds to
thousands of kilometers over vast oceanographic stretches (Plotkin, 1994; Plotkin
et al., 1994; 1995).
Despite the multitude of cues that may be used in long-distance navigation,
operation of a specific cue has not been demonstrated. However, Plotkin (1994)
suggested that water temperature might be the predominant cue used during postreproductive migrations to oceanic feeding areas in the eastern Pacific because of
the spatial and temporal correspondence between turtle movements and the locations
of divergence and convergence zones, thermal fronts, and cool water masses.
8.4 KEMP’S RIDLEY, LEPIDOCHELYS KEMPII
The Kemp’s ridley has a relatively restricted range, occurring in the neritic zone of
the Gulf of Mexico and western Atlantic (Marquez, 1994). Evidence accumulated
from several decades of tag returns and telemetry studies has demonstrated that
Kemp’s ridley is a neritic migrant that swims along the U.S. and Mexican coasts,
nearshore in continental shelf waters (Byles, 1989; Byles and Plotkin, 1994; Marquez, 1994; Renaud, 1995; Shaver, 1999; 2001). Narrow migratory corridors extend
along the entire U.S. and Mexican gulf coast (Byles and Plotkin, 1994).
Reproductively mature females undertake annual migrations from the western
Atlantic and Gulf of Mexico (Renaud et al., 1996) to their principal nesting beach,
Rancho Nuevo, located near the central Mexican gulf coast in the state of Tamaulipas.
Females aggregate nearshore Rancho Nuevo in advance of the nesting season, and
mating takes place approximately 30 days prior to first oviposition for the season
(Chavez et al., 1967; Pritchard, 1969; Mendonca and Pritchard, 1986; Rostal, 1991).
Mating also occurs elsewhere in coastal and inshore waters from south Texas to areas
south of Rancho Nuevo in Tamaulipas and Veracruz, Mexico (Shaver, 1992).
Nesting begins in late April and may last until mid-August (Marquez, 1994).
The vast majority of females emerge en masse to nest at Rancho Nuevo during the
May, June, and July arribadas. The arribadas at Rancho Nuevo typically occur every
28 days (Pritchard and Marquez, 1973). Females lay approximately three nests per
season (Rostal et al., 1997) and remain relatively close to the nesting beach during
the internesting period between clutches (Mendonca and Pritchard, 1986).
1123 book.book Page 228 Monday, November 11, 2002 11:11 AM
The Biology of Sea Turtles, Vol. II
clutches annually at 14-day intervals (Pritchard, 1969; Kalb, 1999), and may use
multiple, geographically distant beaches within a nesting season (Kalb, 1999). Arribada nesting females emerge onto beaches to lay eggs en masse at a few select
beaches in the Atlantic, Pacific, and Indian Oceans. The arribada nesters have strong
site fidelity (Plotkin et al., 1995; Kalb, 1999), lay two clutches approximately every
28 days (Pritchard, 1969; Kalb, 1999), and may delay nesting for 6–8 weeks when
environmental conditions are unfavorable (Plotkin et al., 1997). Once mating and
nesting is completed, olive ridleys quickly migrate back to oceanic waters.
The postreproductive migrations of olive ridleys are unique and complex. Their
migratory pathways vary annually (Plotkin, 1994), there is no spatial and temporal
overlap in migratory pathways among groups or cohorts of turtles (Plotkin et al.,
1994; 1995), and no apparent migration corridors exist. Unlike other marine turtles
that migrate from a breeding ground to a single feeding area, where they reside until
the next breeding season, olive ridleys are nomadic migrants that swim hundreds to
thousands of kilometers over vast oceanographic stretches (Plotkin, 1994; Plotkin
et al., 1994; 1995).
Despite the multitude of cues that may be used in long-distance navigation,
operation of a specific cue has not been demonstrated. However, Plotkin (1994)
suggested that water temperature might be the predominant cue used during postreproductive migrations to oceanic feeding areas in the eastern Pacific because of
the spatial and temporal correspondence between turtle movements and the locations
of divergence and convergence zones, thermal fronts, and cool water masses.
8.4 KEMP’S RIDLEY, LEPIDOCHELYS KEMPII
The Kemp’s ridley has a relatively restricted range, occurring in the neritic zone of
the Gulf of Mexico and western Atlantic (Marquez, 1994). Evidence accumulated
from several decades of tag returns and telemetry studies has demonstrated that
Kemp’s ridley is a neritic migrant that swims along the U.S. and Mexican coasts,
nearshore in continental shelf waters (Byles, 1989; Byles and Plotkin, 1994; Marquez, 1994; Renaud, 1995; Shaver, 1999; 2001). Narrow migratory corridors extend
along the entire U.S. and Mexican gulf coast (Byles and Plotkin, 1994).
Reproductively mature females undertake annual migrations from the western
Atlantic and Gulf of Mexico (Renaud et al., 1996) to their principal nesting beach,
Rancho Nuevo, located near the central Mexican gulf coast in the state of Tamaulipas.
Females aggregate nearshore Rancho Nuevo in advance of the nesting season, and
mating takes place approximately 30 days prior to first oviposition for the season
(Chavez et al., 1967; Pritchard, 1969; Mendonca and Pritchard, 1986; Rostal, 1991).
Mating also occurs elsewhere in coastal and inshore waters from south Texas to areas
south of Rancho Nuevo in Tamaulipas and Veracruz, Mexico (Shaver, 1992).
Nesting begins in late April and may last until mid-August (Marquez, 1994).
The vast majority of females emerge en masse to nest at Rancho Nuevo during the
May, June, and July arribadas. The arribadas at Rancho Nuevo typically occur every
28 days (Pritchard and Marquez, 1973). Females lay approximately three nests per
season (Rostal et al., 1997) and remain relatively close to the nesting beach during
the internesting period between clutches (Mendonca and Pritchard, 1986).
1123 book.book Page 228 Monday, November 11, 2002 11:11 AM