Social and Economic Aspects of Sea Turtle Conservation
363
the harvest of replacement resources (other turtle populations, other fisheries, etc.)
should be expected to follow each anticipated extinction.
Of course, however economically attractive optimal extinction may appear in
the short term, conservationists are not likely to consider it a viable option for sea
turtles or any other renewable resource. The key limitation is in the eventual exhaustion of replacement resources. Examples of this limitation come from the harvest
of Caribbean green turtles. As green turtle harvests from the Bahamas diminished
to near extirpation, harvesting effort shifted to Florida, where green turtle numbers
also plummeted (Carr, 1954). Harvesters then turned to Nicaraguan green turtles, a
population that had also become the replacement resource for Cayman Island green
turtles, a population extirpated following the arrival of turtle fishers formerly from
Jamaica (Lewis, 1940; Parsons, 1962). Although the exploitation of green turtles
aided a prolonged period of colonization throughout the Caribbean, this limited
resource eventually gave out, with reduced numbers of green turtles too small for
large-scale commercial turtling.
The conditions that bring about optimal extinction are important for sea turtle
conservationists to understand. With conditions modified from Clark (1973), extinction is likely to occur when (1) turtles bring a high price relative to the cost of
harvesting them (their harvest remains profitable because price rises with rarity even
as rare turtles become difficult to catch); (2) there is a preference for short-term
harvest in comparison to the generation time of turtle populations being harvested;
and (3) there is no appropriate and complete allocation of harvesting rights (or those
rights are contested among parties). Generally, more than one of these conditions is
needed to drive overexploitation. For example, high profits may become an incentive
for sustainable management if conditions 2 and 3 are not met. Unfortunately, conditions 2 and 3 seem to be readily met for most populations. In commercial operations
driven by demand from consumers with little vested interest in the persistence of
multiple sources of turtles they consume, high harvest rates would be expected to
persist through indications of a failing resource (e.g., increased capture effort per
turtle). Because most sea turtle species take decades to mature (Chaloupka and
Musick, 1997), harvest rates, in units of turtles per generation, can be high even for
small operations. Condition 3 may be the condition most easily met. The multinational distribution of most sea turtle populations (Bowen and Karl, 1997) involves
many stakeholders who would compete for sea turtle resource rights. With multiple
users, difficult harvest monitoring, and uncertainty over the identity of turtles being
harvested (whose turtles are they?), it is currently difficult to achieve appropriate
and complete allocation of sea turtle populations without contestation. Therefore,
the use of sea turtles induces great temptation for optimal extinction, and this justifies
skepticism for their sustained consumptive use. There has been considerable debate
about how to determine sustainable harvest of sea turtles (Mrosovsky, 1997; 2000;
Pritchard, 2000; Frazier, 1996).
Endangered species conservationists are on record with their dread of the additional demand brought about by expanding commercial markets for consumptive
use (Barbier et al., 1990; Fischer, 2001), an increased demand that has been shown
to elevate harvest. In his study of the Miskito turtle fishers of Nicaragua,
Nietschmann (1973) monitored the harvest of green turtles from nearby Caribbean
1123 book.book Page 363 Monday, November 11, 2002 11:11 AM
363
the harvest of replacement resources (other turtle populations, other fisheries, etc.)
should be expected to follow each anticipated extinction.
Of course, however economically attractive optimal extinction may appear in
the short term, conservationists are not likely to consider it a viable option for sea
turtles or any other renewable resource. The key limitation is in the eventual exhaustion of replacement resources. Examples of this limitation come from the harvest
of Caribbean green turtles. As green turtle harvests from the Bahamas diminished
to near extirpation, harvesting effort shifted to Florida, where green turtle numbers
also plummeted (Carr, 1954). Harvesters then turned to Nicaraguan green turtles, a
population that had also become the replacement resource for Cayman Island green
turtles, a population extirpated following the arrival of turtle fishers formerly from
Jamaica (Lewis, 1940; Parsons, 1962). Although the exploitation of green turtles
aided a prolonged period of colonization throughout the Caribbean, this limited
resource eventually gave out, with reduced numbers of green turtles too small for
large-scale commercial turtling.
The conditions that bring about optimal extinction are important for sea turtle
conservationists to understand. With conditions modified from Clark (1973), extinction is likely to occur when (1) turtles bring a high price relative to the cost of
harvesting them (their harvest remains profitable because price rises with rarity even
as rare turtles become difficult to catch); (2) there is a preference for short-term
harvest in comparison to the generation time of turtle populations being harvested;
and (3) there is no appropriate and complete allocation of harvesting rights (or those
rights are contested among parties). Generally, more than one of these conditions is
needed to drive overexploitation. For example, high profits may become an incentive
for sustainable management if conditions 2 and 3 are not met. Unfortunately, conditions 2 and 3 seem to be readily met for most populations. In commercial operations
driven by demand from consumers with little vested interest in the persistence of
multiple sources of turtles they consume, high harvest rates would be expected to
persist through indications of a failing resource (e.g., increased capture effort per
turtle). Because most sea turtle species take decades to mature (Chaloupka and
Musick, 1997), harvest rates, in units of turtles per generation, can be high even for
small operations. Condition 3 may be the condition most easily met. The multinational distribution of most sea turtle populations (Bowen and Karl, 1997) involves
many stakeholders who would compete for sea turtle resource rights. With multiple
users, difficult harvest monitoring, and uncertainty over the identity of turtles being
harvested (whose turtles are they?), it is currently difficult to achieve appropriate
and complete allocation of sea turtle populations without contestation. Therefore,
the use of sea turtles induces great temptation for optimal extinction, and this justifies
skepticism for their sustained consumptive use. There has been considerable debate
about how to determine sustainable harvest of sea turtles (Mrosovsky, 1997; 2000;
Pritchard, 2000; Frazier, 1996).
Endangered species conservationists are on record with their dread of the additional demand brought about by expanding commercial markets for consumptive
use (Barbier et al., 1990; Fischer, 2001), an increased demand that has been shown
to elevate harvest. In his study of the Miskito turtle fishers of Nicaragua,
Nietschmann (1973) monitored the harvest of green turtles from nearby Caribbean
1123 book.book Page 363 Monday, November 11, 2002 11:11 AM