Conservation
Threats to the Bottlenose Dolphin and Other Marine Mammals
Bottlenose dolphins and other marine mammals face a number of conservation
threats due to anthropogenic, or human-induced, impacts on the marine
environment. Marine mammals adapted to the aquatic environment when
it was free from boats, pollution, noise, and human competitors
for fish resources. As human beings have created boats that can
travel to any part of the ocean, new challenges have developed that
threaten the well being and even, existence of many marine mammal
species. Some of the conservation threats to marine mammals include:
- Habitat Degradation
- Boat Traffic
- Fishing Interactions
- Yellowfin Tuna Fishery in the Eastern Tropical Pacific
- Pollution, and
- Direct Takes.
Laws must be created and strictly enforced to protect and conserve
a diversity of marine mammal species. Two such laws or acts are
the:
Marine Mammal Protection Act of 1972 (amendments of 1994) and
the
Endangered Species Act of 1973.
Habitat Degradation
Human beings have exploited the resources of near shore and offshore
ecosystems. Marine mammals utilize both of these environments for
a variety of behaviors, including resting, foraging for prey, traveling,
and socializing. Human use of these areas affects marine mammal
behavior, distribution, and energetics and may cause short- (temporary)
or long-term consequences for these individuals and species. Some
examples of habitat degradation include areas that are disturbed
by traffic from a large number of commercial and recreational vessels;
pollution from sewage, toxins, and oil spills; and noise from boats,
construction, dredging, oil and gas drilling, and explosions. Bottlenose
dolphins and other marine mammals may avoid these areas of habitat
degradation, possibly settling for less hospitable areas with fewer
food resources.
Boat Traffic
As boat traffic in the oceans increases to keep up with today's
society, so do the threats to marine mammals. Whale and dolphin
watching vessels along with commercial and recreational fishing
boats have the potential to present dangerous consequences to marine
mammals. Poorly operated dolphin watching boats and irresponsible
recreational boaters may approach dolphins too closely and too quickly
in order to induce dramatic behaviors such as bow riding and breaching
for paying customers. These boat activities can disrupt the behaviors
of marine mammals and can scatter a group, which is especially harmful
to females with young calves. According to the Marine Mammal Protection
Act of 1972 (MMPA), these actions constitute harassment and are
illegal; however, these illegal activities are rarely enforced.
Although feeding is also forbidden under the MMPA, many boaters
(including whale- and dolphin-watching vessels) feed wild marine
mammals to entice them closer to boats. Marine mammals change their
normal behavior patterns if fed by humans and may depend on people
for food, instead of foraging for it themselves. Dolphins that approach
boats are more susceptible to harm from fishing gear, engine propellers,
poison, and susceptibility to disease from humans and pets. Dolphins
can also bite and injure human beings that do not give them the
food that they expect! The harmful effects of commercial and recreational
fishing vessels are discussed in the next section.
Fishing Interactions
Both commercial and recreational fisheries threaten marine mammals.
By-catch in commercial fishing nets occurs throughout the world's
oceans. By-catch is the incidental capture of a species, such as
the bottlenose dolphins, that is not the target of the fishermen.
The MMPA and its amendments of 1994 were passed in large part to
decrease the number of dolphin by-catch in the fishing industries.
However, by-catch still occurs in both legal fishing industries
such as gill nets and trawling as well as illegal drift nets that
capture any marine life that swims or floats into a huge net that
is towed behind a vessel! Fisheries also threaten marine mammals
by fishing for the same food resources on which the animals depend.
In many parts of the world, marine mammals are seen as competitors
for dwindling fish resources and are poisoned and killed to maintain
the fish resources for human consumption.
Yellowfin Tuna Fishery in the Eastern Tropical Pacific
In the late 1950s, San Diego tuna fishermen developed a new technology
based upon purse-seine nets and a method known as "dolphin
fishing." This fishing method relies on the phenomenon that
some species of dolphins tend to school above yellowfin tuna in
the Eastern Tropical Pacific (ETP), one of the most productive tuna
fishing areas in the world; almost one quarter of the world's tuna
catch comes from the ETP. Because of the close association between
tuna and dolphins in the ETP, tuna boats can simply set nets around
schools of dolphins, knowing tuna will be caught as well. Dolphins
must frequently surface to breathe, making dolphins schools easy
to spot on the surface. Tuna boats then use speedboats, helicopters
and small explosives known as seal bombs to herd dolphins into purse
seine nets which can be up to one mile in circumference. The dolphins
become entangled in the nets along with the tuna, and die. Though
data on dolphin mortality in purse seine nets was very poor prior
to the passage of the MMPA, it has been estimated that mortality
rates in the 1960s were as much as 250,000 per year, and that over
7 million dolphins have been killed through this fishery.
Why dolphins, primarily spotted (Stenella attenuata), spinner
(Stenella longirostris) and common dolphins (Delphinus
delphis), and less frequently striped (Stenella coeruleoalba),
roughtoothed (Steno bredanensis), bottlenose (Tursiops
truncatus) and Fraser's dolphin (Lagenodelphis hosei),
school with tuna is not precisely known. It seems as though the
tuna follow the dolphins, not vice versa, as dolphin fishing works
because the air-breathing dolphins can be corralled into the net.
One of the main predicaments in this issue is the fact that purse
seine dolphin fishing is by far the easiest and most productive
ways to catch tuna. When dolphin fishing was first devised in the
1950s, catches up to 250 tons of tuna per set were not uncommon.
Even by the 1980s, tuna boats were still bringing in an average
of 18 tons per set. Dolphin fishing has larger average catches than
other methods of purse seine fishing and tends to catch larger and
more sexually mature tuna than other methods. Economically, dolphin
fishing is not only the most productive method, but also is the
least harmful to the tuna population as it catches sexually mature
fish.
Dolphin bycatch in the yellowfin tuna fishing industry was already
an issue when the MMPA was passed in 1972; in fact, the MMPA specifically
ordered incidental dolphin kills associated with tuna fishing to
be reduced to "insignificant levels approaching zero."
The tuna industry was granted a two year grace period to develop
new techniques safe for dolphins, but none were forthcoming. Federal
courts enforced a decreasing quota system to reduce kills throughout
the 1970s and early 1980s. A 1981 Amendment to the MMPA asserted
that "[the goal of zero mortality] shall be satisfied in the
case of the incidental taking of marine mammals in the course of
purse-seine fishing for yellowfin tuna by a continuation of the
application of the best marine mammal safety techniques and equipment
that are economically and technologically practicable."
In 1984, more MMPA Amendments were passed to in regards to the
dolphin/tuna issue. The phrase "insignificant levels approaching
zero" was redefined as a quota of "20,500." The Department
of Commerce was required to ban imports of purse-seine-caught tuna
from foreign fishing fleets without dolphin kill rates comparable
to the US fleet's by 1991 and from countries where governmental
dolphin protection program had not yet been instituted.
By 1988, the incidental dolphin kill rate of the US tuna fleet
had dropped, but foreign tuna boats still killed about four times
as many dolphins as US tuna fishermen. It was at this time that
the reauthorization hearings of MMPA were held. The testimony of
an American named Sam LaBudde was crucial to these proceedings:
LaBudde had worked as a cook on a Panamanian tuna boat and provided
graphic footage of dolphins being killed. These proceedings resulted
not only in the reauthorization of the MMPA itself, but new 1988
amendments required US boats to have a special panel made of fine
mesh netting, called a Medina panel, in the rear of the net to help
facilitate the release of dolphins from the nets. 1984 amendments
were also clarified, directing foreign fleets to prove kill rates
of no more than twice the US rate of 20,500 for the year 1989, and
no more than 1.25 times the US rate in 1990.
Also in 1988, environmental groups, frustrated by the fact that
dolphins were still being killed in tuna nets at all, launched a
nationwide consumer boycott of the three major tuna processors in
the US: Heinz's Starkist Tuna, Ralston Purina's Chicken of the Sea
and Pillsbury's Bumble Bee Tuna. Together, these three companies
controlled 70% of US tuna market. In 1990, after two years of concerted
efforts by environmental groups, all three tuna processors agreed
voluntarily to accept only "dolphin-safe" tuna, meaning
tuna that was not caught by purse seine dolphin fishing or drift
nets.
Also in 1990, the Dolphin Protection Consumer Information Act
was passed. This act mandated standards for labeling tuna "dolphin-safe,"
following the same guidelines the tuna companies had: no tuna caught
by setting a purse seine net around dolphins could be labeled "dolphin
safe." Finally, the International Dolphin Conservation Act
was passed in 1992. This provided for a five year moratorium on
purse seine net "dolphin" fishing beginning in 1994. The
US fishing fleets were prohibited from chasing, capturing and setting
of nets on dolphins at all.
With the US tuna market now "dolphin-safe," the rest
of the world began to take notice. At an international meeting of
the Interamerican Tropical Tuna Commission (IATTC) in 1992, the
"La Jolla Agreement" established the International Dolphin
Conservation Program (IDCP). This represented the first time a fisheries
organization recognized the need to deal with the issue of marine
mammal deaths in a fishery. The IDCP called for a decrease in dolphin
deaths, with a goal of under 5000 deaths by the year 2000. The program
includes 100% observer coverage, captain and crew training in dolphin
release techniques, data collection on dolphin biology and bycatch,
and payment of funds by the tuna fishermen to support the observer
program. Only those vessels which comply with these regulations
are allocated portions of the annual limit, and are the only vessels
allowed to set nets on dolphins.
In October of 1995, meetings were held between US and government
officials from Belize, Colombia, Costa Rica, Ecuador, France, Honduras,
Mexico, Panama, Spain, Vanuatu and Venezuela, and representatives
from a number of environmental groups such as Greenpeace, the World
Wildlife Fund, the Center for Marine Conservation, the National
Wildlife Federation and the Environmental Defense Fund. The result
of these meetings was the Panama Declaration, which would make the
La Jolla Agreement binding under international law. Furthermore,
the US would lift the embargoes on foreign tuna caught in purse
seine nets and would change the definition of "dolphin safe"
as stipulated in the Dolphin Information Protection Act of 1992
to mean that no dolphin mortality was observed when the tuna was
caught. The IDCP would become legally binding in the US and Mexico
and would set elimination of dolphin mortality in fishing program
as a goal.
In the summer of 1997, the International Dolphin Conservation
Act, legislation (known as HR 408 and S39) implementing the Panama
Declaration into law, was passed by both the House and Senate and
was signed by President Clinton on August 18th, 1997, becoming Public
Law No. 105-42. The consequences of this new law is that the US
tuna fishermen will again be able to catch tuna using the purse
seine dolphin fishing method and the tuna embargoes on nations using
this method will be lifted. A quota of 5000 dolphins killed per
year was set, with no provisions set in place for future quota reduction.
Before the new "dolphin-safe" label (meaning there was
no observed dolphin mortality) could go into effect, studies were
conducted by the National Marine Fisheries Service to investigate
the impact of purse seine fishing on dolphins. These studies found
that the impacted species of dolphin (including two species listed
as "depleted" under the MMPA, the Eastern spinner dolphin
and the Northeastern offshore spotted dolphin) were not recovering
as expected. Additionally, it was shown that the stress induced
by the dolphin fishing method was likely to have a population level
effect (via stress-induced changes in immune system and reproductive
system function, as well as severe muscle damage (capture myopathy)
from the chase itself. However, in April of 1999, Secretary of Commerce
William Daley issued a rule implementing the change in the dolphin
safe-label, claiming that NFMS was unable to prove that the fishery
was causing in a significant adverse impact on the depleted dolphin
populations. This ruling was challenged in a California court in
Brower vs. Daley, where Judge Thelton Henderson blocked the labeling
change from going into effect on April 11, 2000. This ruling is
currently being appealed; however, for now, the former and stricter
standards of "dolphin-safe" remain in effect.
Environmental groups have divided sharply on the International
Dolphin Conservation Act and its effects on dolphin mortality. Supporters
of the new law include Greenpeace and the Center for Marine Conservation;
these groups feel that only international cooperation can eliminate
dolphin deaths through the tuna fishing industry worldwide. Although
the US tuna fishing fleet was prohibited from setting nets in dolphins
in 1994, as a result many US boats repatriated to countries that
allowed dolphin fishing of tuna. Furthermore, the primary motivation
behind the La Jolla Agreement for the signing nations was to re-enter
the lucrative US tuna market. The environmental groups backing the
new law feared that if the US did not accept the La Jolla Agreement,
the nations involved would no longer have an incentive to pursue
dolphin-safe tuna fishing at all. The La Jolla Agreement has been
successful in lowering dolphin deaths in the ETP, reducing that
figure by over 90% since 1990, to 2657 deaths in 1996. If the US
market had remained closed, the La Jolla Agreement may have been
abandoned completely and worldwide, more dolphins would be killed.
However, environmental groups including the Earth Island Institute,
the Sierra Club and Friends of the Earth were staunchly opposed
to the new law. The dolphin fishing technique causes severe stress
upon the surrounded dolphins and can have serious consequences;
many dolphins may still die unobserved later. Furthermore, nighttime
sets, murky water or unreliable observers may also result in a falsely
labeled "dolphin-safe" catch. Finally, the currently lowered
number of annual dolphin deaths may not be due to the La Jolla Agreement,
but to the fact that fewer fishermen are pursuing tuna at all. As
foreign fishermen are currently unable to sell their tuna in the
US tuna market, fewer boats may be fishing for tuna in the ETP since
they have nowhere to sell it.
The practical result of this legislation is that tuna caught by
encircling dolphins may soon be appearing on US shelves; Mexico
and Ecuador currently have "affirmative findings," meaning
the embargoes on incoming tuna from those countries has been lifted.
Tuna that does not bear the "dolphin-safe" label was caught
during a set where dolphins were observed dead or mortally injured.
For now, tuna bearing the "dolphin-safe" label still means
it was not caught in conjunction with dolphins. However, pending
appeals, it could soon mean that the tuna could still have been
caught by setting nets on dolphins, but no dolphins were seen killed
or mortally injured during the set. Despite these issues, the US
Tuna Federation, which represents the interests of the US tuna industry,
including Bumblebee, Starkist and Chicken of the Sea, has reported
that all US canned tuna processors intend to keep their previous
policy of only purchasing tuna that was not caught by setting nets
on dolphins.
Pollution
Pollution occurs throughout the oceans due to human sewage, oil
spills, toxic leaks and dumping, and noise. Noise pollution is a
rising concern among marine mammalogists today. Marine mammals adapted
to oceans that were void of human produced sounds. Today, the oceans
are being bombarded with sounds from transportation vessels, dredging
and construction, oil and gas drilling, seismic exploration, explosions,
oceans and geologic studies such as ATOC or Acoustic Thermometry
of Ocean Climate, and sonar such as LFA sonar or Low-Frequency Active
sonar. Loud sounds have the potential to cause ear damage or destruction
while low-frequency sounds can affect communication, prey and predator
detection, and navigation. In fact, marine mammals depend on sound
for almost every daily behavior! Although most of the consequences
of the sounds mentioned above are still unknown, the consequences
of some of these noises on marine mammals may be devastating. Research
is necessary and is now being conducted by a number of researchers
to determine the effects of high- and low-frequency as well as loud
sounds within the marine environment on marine mammals. Further
information on LFA sonar can be found at: http://www.publicaffairs.noaa.gov/releases2001/mar01/noaa01037.html
or http://www.surtass-lfa-eis.com/
Direct Takes
Although it has been illegal to take marine mammals in the United
States since the MMPA of 1972, marine mammals are still killed in
some parts of the world for meat, oil, and leather. In several countries
around the world such as Turkey, Peru, Sri Lanka, and Japan, dolphins
are being killed for human consumption and to decrease the competition
for fish resources.
Marine Mammal Protection Act of 1972 (amendments of 1994) (MMPA)
The MMPA, the primary federal legislation designed to protect marine
mammals, was originally passed in 1972 due in part to concern of
dolphin and other marine mammal by-catch in commercial fisheries.
The MMPA prohibits a "take" of a marine mammal, which
is anything that may harm, harass, or kill a marine mammal. In the
amendments of 1994, two types of fishery threats to marine mammals
were identified: Category I activities which are those that frequently
kill or seriously injure marine mammals and Category II fisheries
which are those that occasionally kill or injure marine mammals.
In the Atlantic Ocean, Gulf of Mexico, and United States' Caribbean
waters, bottlenose dolphins were among the species listed as potentially
injured or killed in three of four Category I fisheries and three
of six Category II fisheries. The MMPA is enforced by the National
Marine Fisheries Service (NMFS), which is part of the Department
of Commerce and the National Oceanic and Atmospheric Administration
(NOAA). Information regarding the MMPA regulations can be found
at: http://www4.law.cornell.edu/uscode/16/ch31.html
or at NOAA's web page: http://www.nmfs.noaa.gov/
Endangered Species Act of 1973 (ESA)
The ESA is designed to protect species that are endangered to the
point that they are being threatened to near extinction. The National
Marine Fisheries Service (NMFS) is responsible for marine species
that are protected by the ESA. All decisions that determine which
animals should be considered threatened or endangered are based
on scientific and commercial data, rather than on the economic needs
of human beings. The species that are considered endangered are
those that are in imminent danger of extinction in all of their
significant habitats. A threatened species is one that is likely
to become endangered in the foreseeable future. A recovery plan
is designed for all endangered and threatened species to aid in
their conservation and recovery. Marine mammal species within the
United States' waters that are endangered include the blue, bowhead,
fin, humpback, Northern right, sei, and sperm whales, along with
Caribbean and Hawaiian monk seals. Domestic threatened marine mammals
consist of the Steller sea lion. Other protected species in international
waters include the Chinese and Indus River dolphins, the gray whales
of the Western North Pacific population, the Gulf of California
harbor porpoise, the Southern right whale, the Mediterranean monk
seal, and the Ringed Seal. More information on these species can
be found at: http://www.nmfs.noaa.gov/prot_res/species/ESA_species.html
More information on the ESA can be found on NMFS's web page at:
http://www.nmfs.noaa.gov/prot_res/laws/ESA/ESA_Home.html
or a full version of the act can be seen at: http://www.nmfs.noaa.gov/prot_res/laws/ESA/esatext/esacont.html
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