palm beach dolphin project Archives | Taras Oceanographic Foundation

Common Dolphins – Basic Knowledge

2021-04-11 tarasfoundation Dolphins, Oceans, Science, Threats

PHYSICAL DESCRIPTION: Common dolphins are colorful, with a complex crisscross or hourglass color pattern on the side; the long-beaked common dolphin being more muted in color. When looking at the profile of the two common dolphin species, the short-beaked common dolphin has a more rounded melon that meets the beak at a sharp angle, as compared to the long-beaked common dolphin that has a flatter melon that meets the beak at a more gradual angle.

COLOR: Color patterns on the common dolphin are the most elaborate of any cetacean. The back is dark gray-to-black from the top of the head to the tail dipping to a V on the sides below the dorsal fin. The flanks are light gray behind the dorsal fin and yellowish-tan forward of the dorsal fin, forming an hourglass pattern. Its belly is white. There are large dark circles around the eyes connected by a dark line that runs across the head behind the beak and a black stripe runs from the jaw to the flippers.

FINS AND FLUKES: The dorsal fin is triangular-to-falcate (curved). It is pointed and located near the middle of the back and is black-to-light gray in color with a black border. The flippers are long and thin and slightly curved or pointed depending on geographical location. Flukes are thin and pointed at the tips with a slight notch in the center.

LENGTH AND WEIGHT: Common dolphins can reach lengths of 7.5 to 8.5 feet (2.3-2.6 m) and weigh as much as 297 lb. (135 kg). The short-beaked common dolphin is relatively heavier, and has a larger dorsal fin and flippers than the long-beaked one.

FEEDING: Delphinus delphis feeds on squid and small schooling fish. In some parts of the world, they feed at night on the deep scattering layer, which moves towards the water’s surface during that time. Common dolphins have been seen working together to herd fish into tight balls. Like many other dolphin species, the common dolphin will sometimes take advantage of human fishing activities (such as trawling), feeding on fish escaping from the nets or discarded by the fishermen.

MATING AND BREEDING: Sexual maturity is reached at 3 to 4 years of age or when they reach 6 to 7 feet in length (1.8 to 2.1 m). Calves are 30 to 34 inches at birth (76 to 86 cm ); gestation period is 10 to 11 months.

DISTRIBUTION AND MIGRATION: The common dolphin may be one of the most widely distributed species of cetaceans, as it is found world-wide in temperate, tropical, and subtropical seas. The long-beaked common dolphin is found more in coastal waters; the short-beaked common dolphin is found in offshore waters, including the Eastern Atlantic Ocean as far south as Florida. The common dolphin throughout history has often been recorded in art and literature. It was recently proposed that two forms of this species, the short- beaked (delphis) and long-beaked (capensis) common dolphin, represent two distinct species.

NATURAL HISTORY: Like all mammals, dolphins are warm blooded, breathe air, give birth to live babies, feed their new born milk, and are born with hair. Being warm, blooded, or homeothermic, dolphins maintain a constant body temperature regardless of the surrounding water temperature. Unlike terrestrial mammals, including humans, dolphins are conscious breathers, meaning they must be aware of their breathing to avoid involuntarily taking a breath while underwater. Common dolphins can dive for as long as 15-20 minutes but typically hold their breath for only a few minutes. Common dolphins may live for 35 years or more, with females generally living longer than males. Common dolphins are often found in large herds of hundreds or even thousands. They are extremely active, fast moving, and engage in spectacular aerial behavior. They are noted for stampeding in these extremely large groups across the ocean, riding bow and stern waves of boats, often changing course to bow ride the pressure waves of fast-moving vessels and even large whales. Common dolphins can be frequently seen in association with other marine mammal species.

THREATS: Traditionally, hundreds of thousands of common dolphins have been taken incidentally, along with spinner and pan-tropical spotted dolphins, in purse seine nets used during tuna fishing operations in the eastern tropical Pacific although these numbers have improved. Common dolphins also may be caught accidentally in other fishing gear, such as midwater trawls. Turkish and Russian fishermen used to catch large numbers of common dolphins in the Black Sea for meat (to be used for fish meal) and oil. The fishery stopped after the common dolphin numbers became and remain severely depleted; there are several reports suggesting that the Turkish fishery may have recently resumed. Many common dolphins are taken in a Japanese small cetacean fishery and directly caught in the Mediterranean. Some common dolphins have been taken in Peru for human consumption. Studies suggest that the immune system of these animals can be severely affected by heavy metals, PCBs and other pollutants. The status of common dolphins, relative to OSP, in the U.S. Atlantic Eastern Economic Zone (EEZ) is unknown. The species is not listed as threatened or endangered under the Endangered Species Act. There are insufficient data to determine the population trends for this species.

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We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

Archaeocetes

2021-02-26 tarasfoundation Dolphins, Ocean Sentinels Club, Science, Whales

Well, we can’t exactly tell you what archaeocetes were, but we can tell you what they were not. They were not filter-feeders like the baleen whales (mysticetes), and they had no form of echolocation, as the toothed whales (odontocetes) do. There are very few clues, but we believe they are not categorized by any unique characteristic.

We know they lived from 50 to 35 million years ago (the eocene period) after which they somewhat abruptly disappeared (geologically speaking, that is). Evidence of their existence has been found in all parts of the world. Archaeocetes probably spent some time on land, and some time in shallow coastal waters, feeding in the tidal zone. There is some debate about whether or not the archaeocetes were the evolutionary predecessor to the odontocetes and mysticetes, but either way there is no doubt that the odontocetes and the mysticetes flourished once the archaeocetes disappeared.

Research has shown that two separate families of cetaceans existed then: the Protocetidae were small-bodied animals, less than 3meters long (9 feet), with their nostrils just behind the tip of their long, slender snout and their teeth not unlike those of a wolf. The Basilosauridae was a medium-sized cetacean, ranging in length from 15-20 meters (45 to 60 feet) in length. This was a rather serpentine animal with un-fused vertebrae, allowing for great mobility in all directions. They had a defined rostrum, but no melon (bulge on the front of their head), and small hind, somewhat useless, legs. They were foragers and lived of fish. It is believed that they hauled themselves out of the water onto beaches to breed, in a way similar to that of seals. The first of these two families disappeared nearly 50 million years ago, and the second family disappeared about 40 million years ago.

Among the archaeocetes were also distinct types of dolphins. Although they were very easily recognized as dolphin in appearance and lifestyle, we would say they both had a very primitive air about them. Both animals were about average in size and used a limited form of echolocation. The Kentriodontids were foragers, similar to the modern-day bottlenose dolphins. The Squalidontids had very long rostrums (beaks) and triangular, serrated teeth (similar to shark teeth). It is believed that they had a very active carnivorous lifestyle, not unlike that of the killer whale. What an interesting appearance they must have had, with their blowhole situated at an odd, forward angle, atop but near the front of their heads. Five or six million years ago both these families disappeared, after sharing the planet for about 25 million years. The reason for their disappearance remains a mystery.

Today, we recognize 14 species of baleen whale including the blue, bowhead, right, humpback, minke and grey whale. Baleen whales are generally larger than toothed whales except for the sperm whale which is very big and has teeth. Depending on the source, tooth whales comprise 69 – 76 species and 6 – 10 families.

The two dolphins most frequently encountered in our study area (off Palm Beach County) are the bottlenose dolphin. And the Atlantic spotted dolphin, both members of the family Delphinidae.

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We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

Atlantic Spotted Dolphins -Basic Knowledge

2021-02-21 tarasfoundation Dolphins, Ocean Sentinels Club, Oceans, Science

The Atlantic spotted dolphin is considered playful and acrobatic. They love to ride the bow wave of boats and surf the wake of ships they encounter. They are also more likely to approach humans than other dolphin species and become easily habituated to human activity in the wild, but do not survive in captivity.

PHYSICAL DESCRIPTION
Spotted dolphins are difficult to describe because their size and coloring vary according to their geographic location. Found only in tropical waters, and subtropical waters, there are two recognized species: the Atlantic spe¬cies, Stenella frontalis, and the worldwide species, the pan-tropical spotted dolphin, Stella attenuata. Their long slim beak con¬tains 35 to 48 small conical teeth in each side of the upper jaw and 34 to 47 small, conical teeth in each side of the lower jaw.

COLOR
Spotted dolphins change their coloration as they mature. Newborn calves are dark gray with a white belly (two-tones). As the animal grows older, dark spots begin to appear. First dark spots appear on the lower part of the body (speckled). When sexually mature, light spots begin to appear on the dark upper portion of the body (mottled). Eventually, the spots merge into almost solid color patterns (fused). This color pattern process is a visual indicator of the age of the dolphin.

FINS AND FLUKES
The dorsal (top) fin is tall and curved; the flippers are small and pointed. The flukes are small and pointed at the tips with a small median notch.

LENGTH AND WEIGHT
Length averages about 7 feet (2.1 m); weight averages 220 pounds (100 kg). Calves are 32 to 36 inches (80 to 90 cm) at birth.

FEEDING
Spotted dolphins feed on many varieties of fish and squid found in various water depths. They also feed on small fish and eels found buried in the sand in shallow waters.

MATING AND BREEDING
This species reaches maturity between 6 and 8 years of age or when the animal is about 6.5 feet (2 m) in length. Mating and calving take place throughout the year; the calving interval is believed to be about every 2 – 3 years, but in stressed populations mating takes place at an earlier age and calving at shorter intervals, a response to the enormous mor¬talities suffered from being entangled in nets by the tuna fishery. Gestation is 11 1/2 months and calves are nursed for 11 months. This interval is also longer for male infants, as mothers tend to spend more time caring for the boys. Female calves separate from their mothers earlier and spend a year babysitting the calves of other mothers before becoming mothers themselves.

DISTRIBUTION AND MIGRATION: Atlantic Spotted dolphins are generally found in groups of fewer than 50 individuals but have populations comprising hundreds of animals. These animals are highly social. Schools may contain both sexes and all ages. Some populations are found exclusively in deeper water, some populations prefer to frequent shallow waters, especially for behaviors associated with child care and pregnancy. Atlantic Spotted dolphins are sometimes seen together with bottlenose dolphins.

NATURAL HISTORY
Like all mammals, dolphins are warm blooded, breathe air, give birth to live babies, feed their new born milk, and are born with hair. Being warm, blooded, or homeothermic, dolphins maintain a constant body temperature regardless of the surrounding water temperature. Unlike terrestrial mammals, including humans, dolphins are conscious breathers, mean¬ing they must be aware of their breathing to avoid involuntarily taking a breath while underwater. Atlantic spotted dolphins are capable of diving to up to 60 meters, remaining underwater for up to 6 minutes. They are known to be preyed upon by sharks, but killer whales and other small-toothed whales may also be a threat.
The Atlantic spotted dolphin can often be seen traveling in small pods consisting of up to 15 dolphins. These dolphins enjoy maintaining a high level of social interaction with one another and can often be seen performing leaps and various acrobatic stunts. The Atlantic spotted dolphin communicates using vocal sounds and body language. When it comes to sound these dol¬phins use high-pitched clicks and whistles to communicate about nearby threats, food, a desire to play, and a number of other things. Each dolphin has its own unique frequency which helps them understand who is communicating, and also provides them with a geographic reference (location). This can be extremely useful when a mother for instances needs to keep track of one of her kids or when two friends are communicating with one another in a large pod. Body language is also important for commu¬nication. Dolphins may bump into one another or visualize their body language by spy hopping or leaping out of the water to alert other dolphins of various interests or threats or to display their physical abilities.

THREATS
Spotted dolphins are protected in U.S. waters by the Marine Mammal Protection Act. While the species is not considered endangered, they are, like all marine mammals, exposed to pollutants and biotoxins, and viral outbreaks. Studies of large, high mortality event over the last few decades suggest that the immune system of these animals can be severely affected by heavy metals, PCBs and other pollutants. Atlantic spotted dolphins are not listed as threatened or endangered under the En¬dangered Species Act, and the Western North Atlantic stock is not considered strategic under the Marine Mammal Protection Act. No fishery- related mortality or serious injury has been observed during recent years; therefore, total fishery-related mor¬tality and serious injury can be considered insignificant and approaching the zero mortality and serious injury rate. There are insufficient data to determine the population trends for this species.

We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

Bottlenose Dolphins – Basic Knowledge

2021-02-15 tarasfoundation Dolphins, Ocean Sentinels Club, Science

The bottlenose dolphin is the most studied and best known of all cetaceans. This is primarily due to its ready adaptability to captive environment, such as research facilities and marine parks, and its appearance on the TV show Flipper. This dolphin has an extensive range and is the most encountered dolphin species in coastal U.S. waters.

PHYSICAL DESCRIPTION: The bottlenose dolphin has a long and robust body shape, with a pronounced, stubby beak (hence the name ‘bottlenose’), and a distinct melon. Because 5 of the seven neck vertebrae are not fused together as in other dolphin species, the neck of these dolphins is more flexible. They have about 40-48 sharp conical-shaped teeth in both the upper and lower jaw.

COLOR: The color of bottlenose dolphins may range from light to dark lead gray, with lighter shading on the sides, and a white, sometimes pink to pinkish-gray belly.

FINS AND FLUKES: The dorsal fin is triangular, curved and moderate in size, up to 35 cm in height, and located near the middle of the back. The flukes are proportional, curved, with a deep median notch, and are 65-80 cm from tip to tip. Their flippers are pointed and of moderate length.

LENGTH AND WEIGHT: Adult bottlenose dolphins can reach 4 meters (12 feet) in length, and, in some geographical areas, weigh as much as 650 kg (1,430 pounds). However, in most part of the world their weight seems to be limited to about 350 kg (770 pounds). Males are typically larger than females.

FEEDING: These dolphins can be found foraging in deep and very shallow waters. They may hunt and feed individually or in a concerted effort of a group, chasing fish against the water surface, onto mud banks, and shorelines. Association with human fisheries is also reported. They consume about 8-15kg (15-30 pounds) of food each day. Their diet includes a variety of fish species, but also squid and crustaceans.

MATING AND BREEDING: Male bottlenose dolphins reach sexual maturity at age 10, females between 5 and 10 years of age. The gestation period (pregnancy) is 12 months and calves are born in all seasons although in some geographical areas seasonal peaks during spring and fall have been reported. Females give birth once every 3-4 years. At birth, calves acre about 100 cm (3 feet) in length and may weigh around 10 kg (22 pounds). Calves depend on their mother’s milk for 12-18 months but stay with their mother for up to 5 years learning how to catch fish and the social skills to become a full member of dolphin society.

DISTRIBUTION AND MIGRATION: With the exception of polar waters, bottlenose dolphins are found in every ocean around the world, in coastal waters and the open sea. They are frequently encountered in estuaries, lagoons, bays and harbors. There appears to be a coastal and offshore ecotype. Population density appears to be higher in near-shore areas. Bottlenose dolphins are known to have limited home ranges or may be migratory.

NATURAL HISTORY: Like all mammals, dolphins are warm blooded, breathe air, give birth to live babies, feed their new born milk, and are born with hair. Being warm, blooded, or homeothermic, dolphins maintain a constant body temperature regardless of the surrounding water temperature. Unlike terrestrial mammals, including humans, dolphins are conscious breathers, meaning they must be aware of their breathing to avoid involuntarily taking a breath while underwater. Bottlenose dolphins can dive for as long as 20 minutes but typically hold their breath for only 30 seconds to 3 or 4 minutes between breaths.

Bottlenose dolphins may live for 50 years or more, with females generally living longer than males. They live in social communities, sometimes called pods. Group size in near-shore populations is typically 30 or less while offshore groups may comprise several hundred individuals.

Even though they appear to live in relatively open societies, they exhibit strong social bonds that help provide protection against predators, assist in locating and catching food, and aid in the rearing of their offspring. Like in other social animals, play is an important part of learning. Behaviors such as fish toss, bow riding and seaweed-keep-away are considered play but also help dolphins develop social bonds as well as useful hunting techniques. They use multiple feeding strategies, including “fish whacking,” where they strike a fish with their flukes and knock it out of the water, and driving schools of fish into shallow areas or onto mudflats. Bottlenose dolphins use high frequency echolocation to locate and capture prey, and high-pitched ‘whistles’ to communicate with one another.

THREATS: Bottlenose dolphins are protected in U.S. waters by the Marine Mammal Protection Act. While the species is not considered endangered, they are near depletion in some areas and threatened in many others. Incidental and direct exploitation are generally reported at moderate to low levels. According to NOAA, current threats come primarily from incidental injury and mortality from fishing gear (such as gill net, seine, trawl, and long-line commercial and recreational operations), exposure to pollutants and biotoxins, viral outbreaks and direct harvest in some countries (e.g. Japan and Taiwan). Studies of large, high mortality events over the last decades suggest that the immune system of these animals can be severely affected by heavy metals, PCBs and other pollutants.

In an effort to reduce injury and mortality of coastal bottlenose dolphins along the eastern seashore of the U.S., the National Marine Fisheries Service implemented the Bottlenose Dolphin Take Reduction Plan (BDTRP). This initiative includes provisions for research and education, and requires modifications of fishing practices for small, medium, and large-mesh gill-net fisheries from New York to Florida.

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We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

The Face is Familiar, but …

2021-02-01 tarasfoundation Dolphins, Ocean Sentinels Club, Science

The casual identification of individual cetaceans probably started when humans began interacting with coastal species over a century ago, when whalers and fishermen could identify a few individual killer whales by the shape and coloration of the dorsal fin. This technique, much refined, is still used today.

Scientists, studying cetaceans have long understood and appreciated the need to track individual whales or dolphins. Identifying individuals can help in the collection of information on group composition, site fidelity, movement patterns, population size, as well social structure. Given that dolphins and whales are extremely social animals, understanding the social structure of the population is vital to understanding cetaceans.

Most cetacean studies are conducted from the surface, where the dorsal fin is often the only visible part of the dolphin and therefore the only part usable as an identifier. Luckily, the trailing edge of the dorsal fin, which consists of a thin sheet of flesh and connective tissue, is the most identifying feature of most dolphins and porpoises. Small nicks or larger notches in this area of the dorsal fin are consistent markings that can be used to track individuals over time. However the shading, coloration and overall shape of the dorsal fin can also be helpful.

Some cetaceans have other areas that are more useful as identifiers. The humpback whale has unique markings on the bottom of its flukes, the right whale has large crusty growths on its upper lip that grow in unique patterns and are used to identify individuals and the spotted dolphins have spots; clusters and constellations of spots which are great individual markings and very helpful in the identification process. These dolphins, however, get more and more spots as they develop from infants to adults, identifying spot clusters get covered by new spots, and so it is important to continuously track them over time. All of these identifiers are, in most cases, very subtle, and hard to track in the field. This is where capturing images with photo or video cameras becomes important.

In nearly all studies of cetaceans that track individuals, photo-identification techniques are used to some degree. Most researchers depend on their cameras and photo files a great deal. To get a usable id photo from the surface, it is important to get the dorsal fin on film from a 90-degree angle. This eliminates distortion from angle and helps prevent misidentifications. Any time, we can observe dolphins from underwater, we can use the entire body of the dolphin for identification purposes, which can be very useful, especially in the case of spotted dolphins where we use the spotting pattern across the entire body to identify individual dolphins.

As any field researcher will tell you, it takes a great number of photos to get usable shots. But then, experience does matter and now that we use digital photography, having to throw away bad shots does not hurt as much as it did when we used film.

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We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

In the Eyes of the Dolphin

2021-01-24 tarasfoundation Dolphins, Ocean Sentinels Club, Science, Whales

Cetaceans have extraordinary eyesight.

Dolphins can use their sonar to detect complex shapes and identify them visually. Captive animals have been known to throw frisbees and catch fish without using their sonar. And at any oceanarium it is common to witness dolphins demonstrating their amazing ability to leap out of the water and touch a small target many feet above the surface. These same dolphins repeatedly sail over tightropes and through hoops without touching them, often times in unison. All demonstrating that cetaceans are capable of seeing, not only underwater, but also in air and from water to air. The combination of their visual acuity and sonar abilities makes dolphins well equipped to evaluate any and all objects in their environment.

When the ancestors of the modern dolphin re-entered the water, so many eons ago, their eyes and eyesight went through some major transformations.

On land, eyesight is primarily challenged by dust and the threat of physical harm. These problems are counteracted by hairy eyebrows and lashes and eyeballs that are located in deep sockets of the skull for protection. Tears help wash away dust and clean the eyes. In the sea, the challenges to the eye are more associated with salt and particles in the water, as well as the massive pressure associated with deep dives. Cetacean eyes are encapsulated to protect the shape and integrity of the orb from pressure during dives. There are no dolphin tears, instead special glands secrete oil that continuously wash the surface of the eye to prevent irritation from salinity.

Land animals depend on detection of movement, position, color, detail and sharpness as visual cues. Dolphin vision is more dependent on brightness. The cetacean eye is adapted to perform at depths where light is minimal. At thirty feet, as much as 90% of sunlight is lost and color disappears. The dolphin pupil is capable of opening enormously wide to enhance brightness. The eyes are also lined with a highly reflective substance that concentrates light, similar to the silver of an old traditional headlight. The eyeball has an oval shape, and the lens is positioned to prevent even the weakest ray of light from escaping the retina.

On the other hand, dolphins must see not only at lightless depths, but also at or just below the surface, where it is the brightest. Due to water movement and its effect on sunlight, it can be more than seven times brighter just below the surface than it is above the water. The eye is equipped with a flap like structure that closes over the restricted pupil. It can look as if the dolphin has two tiny pupils at times. Even so, the ability of the dolphin to go from near complete darkness to extreme brightness is one of the miracles of the dolphin eye.

The position of the dolphin eye on each side of the head not only provides additional protection from the onslaught of ocean particles as the dolphin swims forward through the water, but also allows for a nearly complete field of vision. This position of the eye provides some stereo vision directly below them, but also creates a blind spot directly in front of the dolphin. This is one of the places where the sonar comes in handy as they can virtually “see” anything in this blind spot… with sound.

Dolphins don’t just use their eyesight to locate food. The structure of dolphin societies suggests a strong use of visual cues in communication. It makes perfect sense that in an environment where danger can come from any and all directions, silent communication is important. Body posture and subtle swimming techniques can effectively give the others a warning. They can also express irritation, initiate romance and/or provide comfort. An S-shaped body posture by an individual is thought to represent some degree of annoyance, an inverted swim under a female by a male suggests courtship, and companions often swim side by side, eye to eye and rub pectoral fins, possibly during new or unique situations.

Since the dolphin body has adapted to be optimum in the aquatic world, they have lost the ability for facial expression common in terrestrial mammals. They cannot smile with satisfaction, nor grimace in pain. Therefore there must be a lot to be seen in the eye of the dolphin. As many of us here at the Palm Beach Dolphin Project can attest, dolphins are not only capable but sometimes insistent on making eye contact. Not only with each other but with us as well. Here’s looking at you kid!

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We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

Florida’s Wild Dolphins Reveal Unique Social Feeding Behavior

2021-01-09 tarasfoundation Dolphins, Health & Well-Being, Man's Future, Ocean Sentinels Club, Oceans, Science, Threats

For the last decade, the Taras Oceanographic Foundation, under a general authority of the National Marine Fisheries Service, has been conducting dolphin surveys in Palm Beach County. We position or boat within three miles from shore, and travel at slow speed, until we see dolphins. We will then follow the dolphins long enough to photograph each dolphin and document their behavior. And although we have studied wild dolphins for decades, we still find new and different behaviors that are remarkable.

There are days when bait fish seem to fall fro m the sky. On those special days, when the seas are flat, we watch all kin ds of fish jumping out of the water; some high in the air in a single arc, others low and repeatedly as they travel some distance. Flying fish routinely glide, with ease, for several meters. Ballyhoo and Bonita will jump to avoid being eaten. Every once in a while, a clever dolphin will take advantage of these jumping fish; a clever dolphin like Odyssey, and her offspring.
Odyssey was conducting a master class in the art of catching fish. And when I say ‘catching fish’ I mean CATCHING fish. She was throwing a fish into the air, and artfully catching with in her mouth. She demonstrated the process a few times for her calf, and then did something remarkable.

She bit off the head of the fish, before throwing the body in the air, for her calf to catch. We could not help but make the comparison of a mother cutting the crust off a sandwich, before serving it to her child. But it is more than that; she was keeping her calf safe.
For the significance of this simple act, we need to first ex amine the basic anatomy of a fish. Fish use gills to acquire oxygen from the water. These gills are located just at the base of the head. When a fish breathes, it draws in a mouthful of water and pulls the sides of its throat together, forcing the water through the gill openings, which expand away from the body.

Dolphins do not chew their food. It is imperative, therefore, for a dolphin to swallow their prey, head first. If a fish were eaten tail first, it might expand its gills while passing through the throat of the dolphin and become wedged. In all the necropsies I performed, I once found one dolphin with a fish caught in its throat. The fish was swallow ed tail first, and the res ult was deadly. Back to Odyssey and her calf.
She was biting the heads off the fish, so her calf would not catch the fish backwards and choke to death. She threw the fish body high in the air, and her calf made repeated attempts to make the catch. More likely motivated by the game than the food, the small dolphin was still nursing and probably not too hungry. Over the next few months, as this calf grows, Odyssey will insist it hunt down its own food. The catching strategies learned now, will be all the more important in the future.

But even the best strategies and the most prepared youngster will not grow to be an adult unless there continues to be the abundance and variety of fish to eat. We are currently living through the sixth mass extinction event this planet has experienced. ln the past, these epic occurrences were the result of volcanic eruptions or asteroids striking the earth, but this time they are our own doing.

Why is it important to study dolphins? Sure they are cute and all, but why should anyone support such endeavors? Because in many ways, we are alike. Dolphins eat the fish we eat. They raise their kids to be better citizens and work every day to make a living and support their families. They are the masters of the ocean environment; a subject about which we are remarkably naive. And the ocean is vital to the survival of us both.

Although we continue to harvest the resources the oceans provide, at unsustainable rates, we could learn from the marine mammals how to find areas of highest productivity and hunt selectively. As we increase the noise in the ocean with our recreational watercraft, commercial ships and military exercises, we learn from the dolphins that in the deep ocean, it is by listening and hearing we can have the best vision. Marine mammals are the ocean canaries, warning us about the disastrous effects of pollution and habitat destruction, and they can be our guides to find answers, to questions we have not yet thought to ask about the ocean realm.

It is through the long- term studies like the one we have been carrying out in Palm Beach waters, that dolphins teach us about the ocean, the world and ourselves. We just have to keep going to school.

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We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

Dolphins as Sentinels for Oceans and Human Health

2020-11-15 tarasfoundation Dolphins, Health & Well-Being, Ocean Sentinels Club, Science, Threats

Over the past 50 years, a great number of previously un-known human diseases emerged, while other well-known maladies, including cholera and tuberculosis, have seen a significant resurgence. Not surprisingly, dolphins and other marine mammals experience a similar trend, with various papillomaviruses, dolphin poxvirus, lobomycosis, various neoplastic diseases, and algal bloom bio-intoxication being among the better-understood disease agents or diseases. Our experience in human medicine should cause all of us to be concerned about the deterioration of aquatic eco-systems, coastal freshwater or marine, especially since they support more than half of the population in the U.S. alone.

Monitoring the overall health status of dolphins provides an excellent avenue to evaluate the wellbeing of entire aquatic systems, and identify possible environmental trends. Dolphins are the ocean canaries, warning us about existing and emerging threats not only to the aquatic eco-systems, but also to human health. But dolphins are also charismatic and instill the desire to be part of a solution in many people who otherwise may not care. No doubt, it is in our own best interest to closely observe any patterns that could affect us.

Let’s focus here on the most talked about water-related issue in the past two months in south Florida has been the catastrophic, harmful algae bloom that descended onto the Port St. Lucie River lagoon and associated waterways all the ay to the coastline. Algae blooms have become a regular occurrence in this area for years, but this year’s outbreak was larger by order of several magnitudes.

While some people may think that such algae blooms represent little, if any dangers, it is well established that such blooms produce neurotoxins that can kill dolphins and other marine life, as well as biotoxins that affect human health. Among those threats to our own wellbeing are brevetoxins and saxitoxins that cause poisoning, and okadaic acid, which causes diarrhea.

Some recent disease outbreaks (epizootics) among bottlenose dolphin populations in southeast Florida serve as prime examples of how studying dolphins can help us manage health risks. Several of these outbreaks were associated with brevetoxins, produced by a dinoflagellate called Karenia brevis. That is the same species causing the so-called red tides. Brevetoxins are known to kill and/or contaminate fish and shellfish. Once we consume those, or simply inhale toxic aerosols, we will fall ill. It is noteworthy to emphasize that the actual exposure may be delayed, meaning that the risk to human health continues long after, or far away, from the original dinoflagellate bloom.

In sum, any increase in toxins, whether due to natural or anthropogenic cause, in our coastal habitats must be of great concern to us. While we may not yet fully understand how these toxins are absorbed and travel through the entire food chain, there is no doubt that dolphins can serve as the sentinels for ocean and human health.

We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

Why It Is Important To Study Wild Dolphins

2020-10-04 tarasfoundation Dolphins, Ocean Sentinels Club, Science

Most people love whales and dolphins. They think of them as intelligent creatures. They have heard stories of dolphins coming to the aid of stranded sailors, guiding swimmers back to shore and engaging in cooperative hunting with local fishermen. They feel whales and dolphins are important. And they are right! Maybe more than you might think!

Whales and dolphins embody most of what we need to understand about oceans. They are predators at the top of the food chain and can tell us a lot about what is important in the ocean; where are sites of high productivity, what is the most energy efficient way to travel, and what are the best senses to use in the water.

Because of their complex behavior and social structure, whales and dolphins are especially interesting. But they also offer us a window into the physiological and anatomical adaptations to aquatic life; information we can apply to echolocation and boat sonar. More than valuable intellectual exercises, these studies help us understand phenomena such as population decline, recovery, and extinction, and teach us to care about the world. Generally, understanding begets caring.

Further, whales and dolphins are a vibrant part of the global ecosystem and their populations have been severely affected by, and continue to be extremely vulnerable to human impact, including interactions with fisheries and whaling. Above all, marine pollution and habitat degradation looms as the most menacing threats of all. If we have any philosophical leanings towards preserving nature, either for future generations or for its own value, than learning enough to prevent this damage is crucial.

Lastly, whales and dolphins, are the archetypal ‘charismatic mega-vertebrates’. Throughout centuries, whales and dolphins have played major roles in myths and legends. Every culture that has come into contact with an ocean, have created myths and legends about how whales and/or dolphins came into being, and what their existence means to the world and to us.

In our times, whales and dolphins have come so symbolize, more than any other species, the concern for the environment and have become a special symbol of sharing the earth. People react to them with empathy and express concern for their welfare. They epitomize and illustrate many of the problems humans inflict on the sea. They engender, in people who might not otherwise care, a wish to improve the ‘health’ of the marine environment. The huge interest in these animals can therefore be used to encourage interest in the sea more generally, with whales and dolphins becoming flagships or ambassadors of the oceans.

All that makes it important to study these wonderful creatures. If you understand dolphin echolocation and how it works, then you have the tools to apply that knowledge. If you are a conservationist and are concerned about dolphin entanglement in nets, knowledge allows you to reduce that risk. The application of the knowledge depends on what you value: for an academic, to further knowledge and understanding; for an applied researcher, to be able to provide information to managers on the implications of a range of management options, for a conservation biologist: to find ways of ensuring the health of populations and habitats.

For more than thirty years, bottlenose dolphins (Tursiops truncatus) have been studied along the west coast of the United States, the Gulf of Mexico and along the eastern sea border, from the Carolinas to the southern tip of Florida. I have been involved with Coastal Dolphin Conservation through the Palm Beach Dolphin project of the Taras Oceanographic Foundation, headquartered in Jupiter, Florida. This project provides critical information on coastal dolphin communities, their lives and societies and shed light on how the health of these top predators, and the conditions of the natural resources they depend on, may directly or indirectly impact our own health and well-being.

In light of the enormous impact whales and dolphins have on humans and their lives, it is not difficult to understand why studying them serves the support of all of us. Search the Internet for the word dolphin sometime and see how many ‘hits’ you get. People believe that whales and dolphins have value and people put their money in things they hold interesting.

Why do dolphins hear sounds up to 150kHz while we hear only to 15? What is there to listen to anyway? Why do only male humpback whales sing and why don’t females? What directs Humpback whales in Hawaii to swim directly north in the summer? How do they know which way is North? Do dolphins ‘see’ an image in their brain from echolocation signals that is similar to what we see with our eyes? Does a dolphin think, and if he does, what does he think about? Do whales dream? Why are blue whales the biggest animals that have ever lived on earth? Why do dolphins have pointy rostrums? But most importantly why does anyone care about the answers to these questions? The main point is that people do care, and this is why we should all take a stand, and invest our time and money into understanding and protecting these marvelous marine mammals. No doubt, life is better with dolphins around.

Threats to Whales and Dolphins

2020-09-07 tarasfoundation Dolphins, Health & Well-Being, Ocean Litter, Ocean Sentinels Club, Oceans, Threats, Whales

Whales and dolphins are a vibrant part of the global ecosystem and their populations have been severely affected in various ways.

Many species have been over-hunted in the past, and several populations are reduced to a small fraction of their original levels. They are vulnerable to entanglement in fishing gear and incidental catch in gillnets is one of the most serious threats to marine mammals. These fishery operations may well cause the extinction of several small cetacean populations within the next few decades, including the Vaquita and Chilean dolphins. Collisions between larger whales and ships (ship strikes) occur with regular frequency and represent a significant cause of death and traumatic injury. Because toothed whales and dolphins are top predators and thus at a higher tropic level in the food chain, they are especially prone to bio-accumulating toxins, such as heavy metals, persistent organic pollutants (POPs) and endocrine disrupting chemicals (EDCs). However, as recent research has demonstrated, such toxins and pollutants also negatively impact baleen whales.

Another threat to the health of whales and dolphins comes from the petroleum industry. Seismic surveys, which are used to discover oil and gas field situated below the seabed are, at a minimum, suspected to damage the complex hearing system of these marine mammals. Once the oil extraction processes is under way, the negative impacts shift habitat loss and exposure to hydrocarbons, lubricants and outright pollutants and toxins used in the process.

Loss of whale and dolphin habitat is directly linked to increasing human activity in and along marine environments. The aggregation of wastes we allow to flow into our streams and estuaries, and ultimately into the oceans, is a biochemical soup carrying thousands of different chemicals. Rainwater and snow melt, that run off from congested urban areas, collect street oil and chemicals as well as many metals. Runoff into streams and rivers adjacent to farmlands carry tons of suspended particles of soil. This is not only damaging to fish but can also choke-out submerged oxygen-giving grasses in coastal woodlands, bays or estuaries. Runoff from timber harvesting activities, especially clear cutting, deprives the exposed land of thousands of tons of soil and has caused the pollution of some of the most valuable spawning grounds for trout and salmon in the Pacific Northwest. Runoff of the nitrogen and phosphorus components of fertilizers leads to an oxygen depletion in the water. This depletion has caused massive fish die-offs and can wipe out whole areas of marine habitat necessary to maintain the life cycles of myriads of species of aquatic life.

Marine debris is a visible expression of human impact on the marine environment. Debris is more than an aesthetic problem, it poses a real danger. Ocean currents carry milk cartons, toothbrushes, cigarette lighters, and other familiar plastic items around the world. In some areas, such as the Central Pacific Gyre, plastics outnumber plankton seven to one.

The number of marine mammals that die each year due to ingestion and entanglement of debris approaches 100,000 in the North Pacific Ocean alone. Worldwide, 82 of 144 bird species examined contained small debris in their stomachs. Plastic is the most far-reaching man-made threat facing many marine species. Over time, it reacts with sunlight and turns into small plastic polymer molecules. It turns out that these plastic polymers are sponges for DDT, PCBs and other toxins that don’t dissolve in seawater. Plastic pellets have been found to accumulate up to one million times the level of these poisons that are floating in the water itself. These pellets are consumed by baitfish, which in turn are consumed by larger fish, eventually finding their way into the stomachs of large predators, such as dolphins and toothed whales, and our own.

Other human activities, such as the construction of shipping channels and marinas, and the recreational use of coastal areas, including resort development, are likely to have a negative impact on the lives of whales and dolphins using the same areas.

Last but not least, climate change, with its changes of sea temperature, sea level rise, changes in salinity, just to name a few, will undoubtedly change the socio-ecology of whales and dolphins. Species inhabiting the high latitudes, such as bowhead, narwhal, beluga may be the first to feel the impact due to diminishing food resources, such as krill. But other species, such as humpback whales and killer whales will likely experience significant changes in their food supply, resulting in changes of existing migration patterns and a shift of home ranges.

Whales and dolphins are facing enormous challenges and threats. They are the ocean canaries, warning us about the disastrous effects of pollution and habitat destruction, and they can be our guides to where to look for answers about how our oceans work. If we have any philosophical leanings towards preserving these wonderful creatures and the oceans, either for future generations or for its own value, than learning enough to prevent any further damage is crucial.

We all depend on a healthy ocean; a healthy ocean depends on us. Let us be the change we would like to see in the world. Our new Ocean Sentinels Club is proof that conservation can be fun, rewarding and effective. The Club unites and empowers citizens to advocate for the conservation of dolphins and the marine environment across Palm Beach County, and beyond. Join us. The time is now. It begins with you.

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