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Whale Seasons in Costa Rica

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In Costa Rica there are two seasons to spot the humpback whales. They migrate from their feeding areas in the North and South Americas to our warm tropical waters for mating. These whales are characterized as being very sociable, but usually travel alone or with their offspring. They are rarely found in groups, which are mostly formed by males, to compete for the females. One of the strategies the whales use during their breeding season is to stay in warm shallow waters, such as bays, because their geographic features provide better protection for their young, known as a calves.

In Costa Rica we have the great Coronado Bay located in the South Pacific. This bay includes the waters of the Marino Ballena National Park, Drake Bay and Cano Island. The temperature and depth of the water around Cano Island provide some of the best conditions for reproduction and protection of the calves in their first weeks of life. This is also the area where the majority of migrating whales give birth to their young, giving it an important biological value. The conditions of the Coronado Bay area favor ecotourism, making it the largest in the tourism industry for the sighting of cetaceans in Costa Rica, especially for humpback whales. Three species of dolphins are seen regularly, along with the occasional visit from Bryde’s whales, pilot whales and false killer whales.

The migration of the humpbacks whales to Costa Rica occur at two different times: [Read more…]

Olive Ridley Sea Turtles

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Turtles -Tortugas Cano Island TourHow did the olive ridley get its name?

Olive ridley sea turtles are named after the olive colored shells that many turtles of this species have.

What do they look like?

Olive ridleys are similar to the Kemp’s ridley sea turtles. The two species are the smallest of all sea turtles. An adult olive ridley sea turtle can weigh up to 100 pounds and is 24-30 inches long. The hatchlings are about 1.5 inches long and weigh several ounces. The carapace varies from olive to grey-brown or grey-black. Hatchlings are greenish-black. The carapace of the olive ridley is usually a rounded heart-shape.

Where do they live?

Olive ridley sea turtles live primarily in the tropical regions of the Pacific, Indian, and Atlantic Oceans. They nest on the Pacific shores of the American tropics, as well as in the Indian Ocean and along the northeast coast of South America.

How long do they live?

It is unknown how long olive ridleys live, but like other sea turtles, they are likely long-lived.

What do they eat?

Olive ridley sea turtles eat crabs, shrimp, rock lobsters, and jellyfish. These make up their main diet in the western Atlantic and eastern Pacific Oceans. There are data indicating that olive ridleys in other parts of the world eat mainly algae.

What is an “arribada”?

Arribada is the Spanish word for arrival. It is used to describe the mass nesting of olive ridley sea turtles. Nesting in large groups may be a defense against predators or a result of environmental factors influencing nesting. With many turtles coming ashore together and many nests subsequently hatching at the same time, it may help them to reduce predation. However, an arribada also makes the species susceptible to massive harvests by men, or natural disasters that could kill thousands of sea turtles at one time. Scientists do not know exactly what conditions bring all the sea turtles ashore to nest. Possibilities include moon or tide phases, and climate or weather conditions.

When and where do females lay their eggs?Sea Turtle

Female Olive ridley sea turtles are able to lay eggs between 10 and 15 years of age. A female olive ridley will nest at night 1-3 times per season. Female sea turtles always return to the beach where they were born, their natal beach, to lay their eggs. The olive ridley sea turtle nesting season ranges worldwide from June to December, with the peak period in September and October.

There are several important arribada beaches along the Pacific coast of Mexico and Central America, and especially in Costa Rica. There are also important sites in the Indian Ocean and in the South Atlantic Ocean. Females clear the sand with their front flippers, dig an egg chamber with their rear flippers, lay 100-110 eggs, and then use their front flippers to cover the entire area with sand. The eggs incubate for approximately 55 days before they hatch.

Who are their predators?

Hatchlings are much more susceptible to predators than adults. Crabs and raccoons feed on the hatchlings when they first emerge from their nests and fish and seabirds are a threat to hatchlings in the water. Very few hatchlings will survive to adulthood. Sharks are the principal predators of adult sea turtles, and their long flippers are especially vulnerable. Man is also a predator of the olive ridley turtle.

How many are there?

Prior to the time when sea turtles were hunted for their meat, eggs and leather, it is estimated that there may have been as many as 10,000,000 olive ridleys in the Pacific Ocean. Today the population is greatly reduced from historical times.

Why are they in trouble?

Humans have heavily exploited olive ridley sea turtles. They are killed for their meat and leather, and their eggs are collected off the beaches before they even hatch. The historic olive ridley fishery in Mexico was the largest turtle fishery in the world, with turtle products sold to Japan for high prices. Olive ridley sea turtles are often caught in shrimp trawls, longlines, and gill nets and drown because they cannot make it back up to the surface to breathe. Other problems include pollution and the loss of their nesting habitat as beaches become more developed. In the Eastern Tropical Pacific olive ridleys have been observed entangled in the debris that accumu- lates in weed lines. Sea turtles can also confuse trash and debris for food, and this can cause injury or even death. One surprising threat to sea turtles is the balloons that people let go. These balloons often float over the ocean before popping, and sea turtles can choke on the pieces of the balloon that fall into the water.

What can you do to help sea turtles?

It is possible for anyone to help support sea turtle conservation. You can help participate in beach cleanups or attend a public sea turtle walk. You can do a presentation on turtles for a class to raise awareness, adopt a turtle, or follow a sea turtle telemetry project. You can help just by remembering not to release balloons or throw trash into the ocean. You can help spread the word to your family and friends that sea turtles are an important part of our environment and should be protected.

*Adapted from: NOAA’s National Marine Fisheries Service – For educational purposes only

Humpback Whale

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THE HUMPBACK WHALE
The humpback whale (Megaptera novaeangliae) is a Baleen whale. One of the larger rorqual species, adults range in length from 12-16 metres (40-50 ft) and weigh approximately 36,000 kilograms (79,000 lb). The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water. Males produce a complex whale song, which lasts for 10 to 20 minutes and is repeated for hours at a time. The purpose of the song is not yet clear, although it appears to have a role in mating.
Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 kilometers each year. Humpbacks migrate from the polar waters of South America between July and October and from the cold waters of North America to warmer tropical waters between the months of January and April. The whales come to the warm and quiet waters surrounding the Marino Ballena National Park, Caño Island, and Osa Peninsula area to give birth to their young.
Like other large whales, the humpback was and is a target for the whaling industry. Due to over-hunting, its population fell by an estimated 90% before a whaling moratorium was introduced in 1966. Stocks of the species have since partially recovered; however, entanglement in fishing gear, collisions with ships, and noise pollution also remain concerns. It is believed they number about 30,000-40,000 at present, or about 30-35% of the original population.
PHYSICAL DESCRIPTION OF THE HUMPBACK WHALE
The head of a humpback whale is broad and rounded when viewed from above, but slim in profile. The body is quite round, narrowing to a slender peduncle (tail stock). The top of the head and lower jaw have rounded, bump-like knobs, each containing at least one stiff hair. The purpose of these hairs is not known. There are between 20-50 ventral grooves which extend slightly beyond the navel.
COLORS OF THE HUMPBACK WHALE
The body is black on the dorsal (upper) side, and black and white on the ventral (under) side. This color pattern extends to the flukes. When the humpback whale “sounds” (goes into a long or deep dive) it usually throws its flukes upward, exposing the black and white patterned underside. This pattern is distinctive to each whale. The flippers range from all white to all black dorsally, but are usually white ventrally.
FINS AND FLUKES OF THE HUMPBACK WHALE
About 2/3 of the way back on the body is an irregularly shaped dorsal (top) fin. Its flippers are very long, between 1/4 and 1/3 the length of its body, and have large knobs on the leading edge. The flukes (tail), which can be 18 feet (5.5 m) wide, is serrated and pointed at the tips
HUMPBACK WHALE LENGTH AND WEIGHT
Adult males measure 40-48 feet (12.2-14.6 m), adult females measure 45-50 feet (13.7-15.2 m). They weigh 25 to 40 tons (22,680-36,287 kg).
FEEDING HABITS OF THE HUMPBACK WHALE
Humpback whales feed on krill, small shrimp-like crustaceans, and various kinds of small fish. Each whale eats up to 1 and 1/2 tons (1,361 kg) of food a day. As a baleen whale, it has a series of 270-400 fringed overlapping plates hanging from each side of the upper jaw, where teeth might otherwise be located. These plates consist of a fingernail-like material called keratin that frays out into fine hairs on the ends inside the mouth near the tongue. The plates are black and measure about 30 inches (76 cm) in length. During feeding, large volumes of water and food can be taken into the mouth because the pleated grooves in the throat expand. As the mouth closes water is expelled through the baleen plates, which trap the food on the inside near the tongue to be swallowed.
HUMPBACK WHALES MATING AND BREEDING
Humpback whales reach sexual maturity at 6-10 years of age or when males reach the length of 35 feet (11.6 m) and females reach 40 feet (12 m). Each female typically bears a calf every 2-3 years and the gestation period is 12 months. A humpback whale calf is between 10-15 feet (3-4.5 m) long at birth, and weighs up to 1 ton (907 kg). It nurses frequently on the mother’s rich milk, which has a 45% to 60% fat content. The calf is weaned to solid food when it is about a year old.
DISTRIBUTION AND MIGRATION OF HUMPBACK WHALES
Found in all the world’s oceans, most populations of humpback whales follow a regular migration route, summering in temperate and polar waters for feeding, and wintering in tropical waters for mating and calving. In the Arabian Sea, a year-round non-migratory population of humpbacks appears not to follow this general rule.
NATURAL HISTORY OF HUMPBACK WHALES
At least 3 different species of barnacles are commonly found on both the flippers and the body of the humpback whale. It is also home for a species of whale lice, Cyamus bops. Humpback whales are active, acrobatic whales. They can throw themselves completely out of the water (breaching), and swim on their backs with both flippers in the air. They also engage in “tail lobbing” (raising their huge flukes out of the water and then slapping it on the surface) and “flipper slapping” (using their flippers to slap the water). It is possible that these behaviors are important in communication between humpbacks.
Perhaps the most interesting behavior of humpback whales is their “singing.” Scientists have discovered that humpback whales sing long, complex “songs”. Whales in the North American Atlantic population sing the same song, and all the whales in the North American Pacific population sing the same song. However, the songs of each of these populations and of those in other areas of the world are uniquely different. A typical song lasts from 10-20 minutes, is repeated continuously for hours at a time, and changes gradually from year to year. Singing whales are males, and the songs may be a part of mating behavior.
STATUS OF THE HUMPBACK WHALES
Because their feeding, mating, and calving grounds are close to shore and because they are slow swimmers, the humpback whales were an easy target for early whalers. The International Whaling Commission (IWC) gave them worldwide protection status in 1966, but there were large illegal kills by the Soviets until the 1970’s. It is believed they number about 30,000-40,000 at present, or about 30-35% of the original population.

Humpback WhaleThe humpback whale (Megaptera novaeangliae) is a Baleen whale. One of the larger rorqual species, adults range in length from 12-16 metres (40-50 ft) and weigh approximately 36,000 kilograms (79,000 lb). The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water. Males produce a complex whale song, which lasts for 10 to 20 minutes and is repeated for hours at a time. The purpose of the song is not yet clear, although it appears to have a role in mating.

Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 kilometers each year. Humpbacks migrate from the polar waters of South America between July and October and from the cold waters of North America to warmer tropical waters between the months of January and April. The whales come to the warm and quiet waters surrounding the Marino Ballena National Park, Caño Island, and Osa Peninsula area to give birth to their young.

Like other large whales, the humpback was and is a target for the whaling industry. Due to over-hunting, its population fell by an estimated 90% before a whaling moratorium was introduced in 1966. Stocks of the species have since partially recovered; however, entanglement in fishing gear, collisions with ships, and noise pollution also remain concerns. It is believed they number about 30,000-40,000 at present, or about 30-35% of the original population.

Physical description of the humpback whale

The head of a humpback whale is broad and rounded when viewed from above, but slim in profile. The body is quite round, narrowing to a slender peduncle (tail stock). The top of the head and lower jaw have rounded, bump-like knobs, each containing at least one stiff hair. The purpose of these hairs is not known. There are between 20-50 ventral grooves which extend slightly beyond the navel.

Colors of the humpback whale

The body is black on the dorsal (upper) side, and black and white on the ventral (under) side. This color pattern extends to the flukes. When the humpback whale “sounds” (goes into a long or deep dive) it usually throws its flukes upward, exposing the black and white patterned underside. This pattern is distinctive to each whale. The flippers range from all white to all black dorsally, but are usually white ventrally.

Fins and flukes, length and weight of the humpback whale

Humpbacks TailAbout 2/3 of the way back on the body is an irregularly shaped dorsal (top) fin. Its flippers are very long, between 1/4 and 1/3 the length of its body, and have large knobs on the leading edge. The flukes (tail), which can be 18 feet (5.5 m) wide, is serrated and pointed at the tips. Adult males measure 40-48 feet (12.2-14.6 m), adult females measure 45-50 feet (13.7-15.2 m). They weigh 25 to 40 tons (22,680-36,287 kg).

Feeding habits of the humpback whale

Humpback whales feed on krill, small shrimp-like crustaceans, and various kinds of small fish. Each whale eats up to 1 and 1/2 tons (1,361 kg) of food a day. As a baleen whale, it has a series of 270-400 fringed overlapping plates hanging from each side of the upper jaw, where teeth might otherwise be located. These plates consist of a fingernail-like material called keratin that frays out into fine hairs on the ends inside the mouth near the tongue. The plates are black and measure about 30 inches (76 cm) in length. During feeding, large volumes of water and food can be taken into the mouth because the pleated grooves in the throat expand. As the mouth closes water is expelled through the baleen plates, which trap the food on the inside near the tongue to be swallowed.

Humpback whales mating and breeding

Humpback whales reach sexual maturity at 6-10 years of age or when males reach the length of 35 feet (11.6 m) and females reach 40 feet (12 m). Each female typically bears a calf every 2-3 years and the gestation period is 12 months. A humpback whale calf is between 10-15 feet (3-4.5 m) long at birth, and weighs up to 1 ton (907 kg). It nurses frequently on the mother’s rich milk, which has a 45% to 60% fat content. The calf is weaned to solid food when it is about a year old.

Distribution and migration of humpback whales

Found in all the world’s oceans, most populations of humpback whales follow a regular migration route, summering in temperate and polar waters for feeding, and wintering in tropical waters for mating and calving. In the Arabian Sea, a year-round non-migratory population of humpbacks appears not to follow this general rule.

Natural history of the humpback whaleWhale Tail

At least 3 different species of barnacles are commonly found on both the flippers and the body of the humpback whale. It is also home for a species of whale lice, Cyamus bops. Humpback whales are active, acrobatic whales. They can throw themselves completely out of the water (breaching), and swim on their backs with both flippers in the air. They also engage in “tail lobbing” (raising their huge flukes out of the water and then slapping it on the surface) and “flipper slapping” (using their flippers to slap the water). It is possible that these behaviors are important in communication between humpbacks.

Perhaps the most interesting behavior of humpback whales is their “singing.” Scientists have discovered that humpback whales sing long, complex “songs”. Whales in the North American Atlantic population sing the same song, and all the whales in the North American Pacific population sing the same song. However, the songs of each of these populations and of those in other areas of the world are uniquely different. A typical song lasts from 10-20 minutes, is repeated continuously for hours at a time, and changes gradually from year to year. Singing whales are males, and the songs may be a part of mating behavior.

Status of the humpback whale 

Because their feeding, mating, and calving grounds are close to shore and because they are slow swimmers, the humpback whales were an easy target for early whalers. The International Whaling Commission (IWC) gave them worldwide protection status in 1966, but there were large illegal kills by the Soviets until the 1970’s. It is believed they number about 30,000-40,000 at present, or about 30-35% of the original population.

*Adapted from American Cetacean Society for educational purposes.

Bottlenose Dolphins

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BOTTLENOSE DOLPHINS
The bottlenose dolphin is perhaps one of the most well known cetaceans, because of its widespread use in marine parks and research facilities. The bottlenose dolphin may be best known as “Flipper” from the television series. (as seen in the television series).  In Costa Rica, bottlenose dolphins are usually found in smaller schools ranging from 2 to l2.  These dolphins hunt for food alone and in groups. They’ve been known to whack at fish with their flukes, knocking the stunned prey right out of the water! Found in almost all of the world’s temperate and tropical oceans., they occupy a diverse range of marine habitats from shallow coastal areas to oceanic waters.
Physical description of bottlenose dolphin
This is a relatively robust dolphin with a usually short and stubby beak – hence the name “bottlenose”. The bottlenose dolphin (like the beluga) has more flexibility in its neck than other oceanic dolphins, because 5 of the 7 neck vertebrae are not fused together as in the other oceanic dolphins. There are 18-26 pairs of sharp, conical teeth in each side of its jaw.
Color of bottlenose dolphin
The color of the bottlenose dolphin varies considerably, but generally this dolphin is light gray to slate gray on the upper part of the body shading to lighter sides and pale, pinkish gray on the belly.
Fins and flukes, length and weight of bottlenose dolphins
The dorsal fin is high and falcate (curved) and located near the middle of the back. The flukes are broad and curved with a deep median notch. The flippers are of moderate length and pointed.  Adult length is from 8-12 feet (2.5-3.8 m). These dolphins may weigh as much as 1,430 pounds (650 kg) off Great Britain, though most are much smaller in other parts of the world. Males are significantly larger than females.
Feeding habits of bottlenose dolphins
Feeding behaviors are diverse, primarily involving individual prey capture, but sometimes involving coordinated efforts to catch food, feeding in association with human fishing, and chasing fish into mudbanks. An adult bottlenose dolphin may consume 15-30 pounds (8-15 kg) of food each day. Bottlenose dolphins eat a wide variety of food, including primarily fishes, and sometimes squid, and crustaceans.
Bottlenose dolphins mating and breeding
Males reach sexual maturity at about 10 years. Females reach sexual maturity at about 5-10 years. The gestation period is 12 months. Calving can take place year-round with peaks in some areas during spring and fall. Calves nurse for over a year (12-18 months), and stay with their mothers for 3-6 years learning how to catch fish and other important tasks.
Distribution and migration of bottlenose dolphins
Bottlenose dolphins are found worldwide in temperate and tropical waters, absent only from 45 degrees poleward in either hemisphere. They are frequently seen in harbors, bays, lagoons, estuaries, and river mouths. There appear to be two ecotypes: a coastal form and an offshore form. Population density appears to be higher nearshore. Biochemical studies now are providing more information about the relationship within and between the ecotypes. In some areas, dolphins have limited home ranges; in others, they are migratory. A second species Tursiops aduncus, inhabits the Indian Ocean.
Natural histroy of bottlenose dolphins
Based on a number of studies of nearshore populations, bottlenose dolphins seem to live in relatively open societies. Mother and calf bonds and some other associations may be strong, but individuals may be seen from day-to-day with a variety of different associates. Group size is often less than 20 nearshore; offshore groups of several hundred have been seen. Much of what we know of the general biology of dolphins comes from studies of bottlenose dolphins, both in captivity and in the wild.
Bottlenose dolphin status
The bottlenose dolphin is protected in U.S. waters by the Marine Mammal Protection Act. Bottlenose dolphins are still generally plentiful in numbers, but are near depletion in some areas. Both incidental and direct exploitation of bottlenose dolphins are known to occur, generally at low to moderate levels. The largest direct kills have traditionally been in the Black Sea, where Russian and Turkish hunters apparently have reduced local populations. Bottlenose dolphins are accidentally caught in a variety of fishing gear, including gillnets, purse seiners used to catch tuna, and shrimp trawls. These dolphins also are occasional victims of harpoon and drive fisheries. Live captures of bottlenose dolphins for captivity have had effects on some local dolphin populations in the Gulf of Mexico and southeastern United States, but no commercial live captures have occurred in the U.S. since the 1980’s. Bottlenose dolphins are vulnerable to pollution, habitat alteration, boat collisions, human feeding of and swimming with wild animals, and human disturbance (such as boating). Several die- offs of bottlenose dolphins have occurred. Retrospective analysis of tissues of dolphins that died in 1987-1988 during a large die-off (approximately 800-1,000 dolphins) on the Atlantic U.S. coast indicates that mortality may have been caused by a morbillivirus. This virus has been linked to dies-offs of Gulf of Mexico bottlenose dolphins as well. Dolphins with disease symptoms appeared to have elevated levels of PCB’s, leading researchers to conclude that pollutants may be playing a role in these events. Preliminary evidence from other studies show links between contaminant residues in tissues and impaired immune system function.

Bottlenose DolphinThe bottlenose dolphin is perhaps one of the most well known cetaceans, because of its widespread use in marine parks and research facilities. The bottlenose dolphin may be best known as “Flipper” from the television series.    In Costa Rica, during dolphin encounters, bottlenose dolphins are usually found in smaller schools ranging from 2 to l2.  These dolphins hunt for food alone and in groups. They’ve been known to whack at fish with their flukes, knocking the stunned prey right out of the water! Found in almost all of the world’s temperate and tropical oceans., they occupy a diverse range of marine habitats from shallow coastal areas to oceanic waters.

Physical description of bottlenose dolphin

This is a relatively robust dolphin with a usually short and stubby beak – hence the name “bottlenose”. The bottlenose dolphin (like the beluga) has more flexibility in its neck than other oceanic dolphins, because 5 of the 7 neck vertebrae are not fused together as in the other oceanic dolphins. There are 18-26 pairs of sharp, conical teeth in each side of its jaw.

Color of bottlenose dolphin

The color of the bottlenose dolphin varies considerably, but generally this dolphin is light gray to slate gray on the upper part of the body shading to lighter sides and pale, pinkish gray on the belly.

Fins and flukes, length and weight of bottlenose dolphins

The dorsal fin is high and falcate (curved) and located near the middle of the back. The flukes are broad and curved with a deep median notch. The flippers are of moderate length and pointed.  Adult length is from 8-12 feet (2.5-3.8 m). These dolphins may weigh as much as 1,430 pounds (650 kg) off Great Britain, though most are much smaller in other parts of the world. Males are significantly larger than females.

Feeding habits of bottlenose dolphins

Feeding behaviors are diverse, primarily involving individual prey capture, but sometimes involving coordinated efforts to catch food, feeding in association with human fishing, and chasing fish into mudbanks. An adult bottlenose dolphin may consume 15-30 pounds (8-15 kg) of food each day. Bottlenose dolphins eat a wide variety of food, including primarily fishes, and sometimes squid, and crustaceans.

Bottlenose dolphins mating and breeding

Males reach sexual maturity at about 10 years. Females reach sexual maturity at about 5-10 years. The gestation period is 12 months. Calving can take place year-round with peaks in some areas during spring and fall. Calves nurse for over a year (12-18 months), and stay with their mothers for 3-6 years learning how to catch fish and other important tasks.

Distribution and migration of bottlenose dolphins

Bottlenose dolphins are found worldwide in temperate and tropical waters, absent only from 45 degrees poleward in either hemisphere. They are frequently seen in harbors, bays, lagoons, estuaries, and river mouths. There appear to be two ecotypes: a coastal form and an offshore form. Population density appears to be higher nearshore. Biochemical studies now are providing more information about the relationship within and between the ecotypes. In some areas, dolphins have limited home ranges; in others, they are migratory. A second species Tursiops aduncus, inhabits the Indian Ocean.

Bottlenose DolphinNatural histroy of bottlenose dolphins

Based on a number of studies of nearshore populations, bottlenose dolphins seem to live in relatively open societies. Mother and calf bonds and some other associations may be strong, but individuals may be seen from day-to-day with a variety of different associates. Group size is often less than 20 nearshore; offshore groups of several hundred have been seen. Much of what we know of the general biology of dolphins comes from studies of bottlenose dolphins, both in captivity and in the wild.

Bottlenose dolphin status

The bottlenose dolphin is protected in U.S. waters by the Marine Mammal Protection Act. Bottlenose dolphins are still generally plentiful in numbers, but are near depletion in some areas. Both incidental and direct exploitation of bottlenose dolphins are known to occur, generally at low to moderate levels. The largest direct kills have traditionally been in the Black Sea, where Russian and Turkish hunters apparently have reduced local populations. Bottlenose dolphins are accidentally caught in a variety of fishing gear, including gillnets, purse seiners used to catch tuna, and shrimp trawls. These dolphins also are occasional victims of harpoon and drive fisheries. Live captures of bottlenose dolphins for captivity have had effects on some local dolphin populations in the Gulf of Mexico and southeastern United States, but no commercial live captures have occurred in the U.S. since the 1980’s. Bottlenose dolphins are vulnerable to pollution, habitat alteration, boat collisions, human feeding of and swimming with wild animals, and human disturbance (such as boating). Several die- offs of bottlenose dolphins have occurred. Retrospective analysis of tissues of dolphins that died in 1987-1988 during a large die-off (approximately 800-1,000 dolphins) on the Atlantic U.S. coast indicates that mortality may have been caused by a morbillivirus. This virus has been linked to dies-offs of Gulf of Mexico bottlenose dolphins as well. Dolphins with disease symptoms appeared to have elevated levels of PCB’s, leading researchers to conclude that pollutants may be playing a role in these events. Preliminary evidence from other studies show links between contaminant residues in tissues and impaired immune system function.

*Adapted from American Cetacean Society for educational purposes.

The importance of building REEF resiliency

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Coral reefs are naturally resilient ecosystems, adapted to recover from battering storms that frequently strike the tropical areas where they occur. However, reefs today face many more threats than the occasional hurricane—intensifying global stresses like climate change and ocean acidification are accompanied by increasing local threats from coastal development, destructive fishing practices, careless tourism, and pollution.
It has been shown that both local and global stresses can significantly degrade coral reefs. But how do these different pressures interact? Could acclimatization to a stressful environment actually increase corals’ ability to withstand future stress? A recent paper published by the Public Library of Science (PLoS ONE) provides evidence that such wishful thinking is mistaken.
Rising ocean temperatures can induce coral bleaching, a phenomenon in which corals expel the symbiotic algae that provide an essential portion of their nutrition. Corals may recover their algae and survive if conditions become favorable again, but the stress can reduce their growth rates. Based on studies of coral growth in four locations on the Meso-american Reef around a mass bleaching event in 1998, the conclusion of the recent PLoS ONE paper is evident from its title: “Local Stressors Reduce Coral Resilience to Bleaching.” The study found that coral growth rates at sites that were relatively free from local stressors recovered in two to three years, while growth rates in sites with higher local stressors remained suppressed for at least eight years.
Studies of coral reefs in locations as diverse as Australia, the Coral Triangle, and Bonaire all present similar results: corals are most able to recover from large-scale threats like rising ocean temperatures, water quality decline, and storm damage when they are healthy to begin with. Building reef resiliency by reducing local stressors is the best strategy we have to help them withstand the global threats that will take longer to curtail and are already taking effect.
With data from the National Oceanic and Atmospheric Administration showing record high ocean temperatures this summer, and a new study in the journal Nature indicating that the past decade has seen more frequent hurricanes than any time in the past 1,000 years, it is clear that we must act quickly to bolster reef health and build robustness.
Experts from around the world are advocating networks of effectively managed marine protected areas, coupled with widespread education, poverty alleviation, and alternative livelihood creation, as essential components of a global approach to saving coral reefs.
Although reducing carbon dioxide emissions will be necessary to limit the detrimental impacts of climate change and ocean acidification, the long-term survival of coral reefs depends on our action now to alleviate local pressures and support healthy, resilient reef ecosystems.
*Adapted from the Coral Reef Alliance

The Marino Ballena National Park and Cano Island Biological Reserve are home to some of Costa Rica’s most beautiful coral reefs.  Locals and visitors alike can enjoy some of the best Costa Rica Snorkel and Diving Tours.  The importance of maintaining our beautiful Coral Reefs cannot be understated.

Coral Reefs are naturally resilient ecosystems, however, our coral reefs today face many threats such as, intensifying global stresses like climate change and ocean acidification.  These threats are are accompanied by increasing local threats from coastal development, destructive fishing practices, careless tourism, and pollution.

It has been shown that both local and global stresses can significantly degrade coral reefs.  Studies based on coral growth have found that coral growth rates at sites that are relatively free from local stressors recovered in two to three years, while growth rates in sites with higher local stressors remained suppressed for at least eight years. Studies of coral reefs in locations as diverse as Australia, the Coral Triangle, and Bonaire all present similar results: corals are most able to recover from large-scale threats like rising ocean temperatures, water quality decline, and storm damage when they are healthy to begin with.

Building reef resiliency by reducing local stressors is the best strategy we have to help our coral reefs withstand the global threats that are already taking effect.  It is clear that we must act quickly to bolster reef health and build robustness. Experts from around the world are advocating networks of effectively managed marine protected areas, coupled with widespread education, poverty alleviation, and alternative livelihood creation, as essential components of a global approach to saving coral reefs.

The long-term survival of coral reefs depends on our action now to alleviate local pressures and support healthy, resilient reef ecosystems.

*Adapted from the Coral Current 2009 Autumn Edition – Coral Reef Alliance

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