Parrot Fish

It's hard to decide which of the colorful parrot fish's many unique characteristics is most remarkable.

There’s its diet, which consists primarily of algae extracted from chunks of coral ripped from a reef. The coral is pulverized with grinding teeth in the fishes’ throats in order to get to the algae-filled polyps inside. Much of the sand in the parrot fish's range is actually the ground-up, undigested coral they excrete.

There's its gender, which they can change repeatedly throughout their lives, and their coloration and patterns, which are a classification nightmare, varying greatly, even between the males, females, and juveniles of the same species.

Finally, there are the pajamas. Every night, certain species of parrot fish envelope themselves in a transparent cocoon made of mucous secreted from an organ on their head. Scientists think the cocoon masks their scent, making them harder for nocturnal predators, like moray eels, to find.

Close relatives of the wrasse, parrot fish are abundant in and around the tropical reefs of all the world’s oceans. There are about 80 identified species, ranging in size from less than 1 to 4 feet (30 to 120 centimeters) in length.

Their meat is rarely consumed in the United States, but is a delicacy in many other parts of the world. In Polynesia, it is served raw and was once considered "royal food," only eaten by the king.

article by : national Geographic

Flying Fish Profile

Flying fish can be seen jumping out of warm ocean waters worldwide. Their streamlined torpedo shape helps them gather enough underwater speed to break the surface, and their large, wing-like pectoral fins get them airborne.

Flying fish are thought to have evolved this remarkable gliding ability to escape predators, of which they have many. Their pursuers include mackerel, tuna, swordfish, marlin, and other larger fish. For their sustenance, flying fish feed on a variety of foods, including plankton.

There are about 40 known species of flying fish. Beyond their useful pectoral fins, all have unevenly forked tails, with the lower lobe longer than the upper lobe. Many species have enlarged pelvic fins as well and are known as four-winged flying fish.

The process of taking flight, or gliding, begins by gaining great velocity underwater, about 37 miles (60 kilometers) per hour. Angling upward, the four-winged flying fish breaks the surface and begins to taxi by rapidly beating its tail while it is still beneath the surface. It then takes to the air, sometimes reaching heights over 4 feet (1.2 meters) and gliding long distances, up to 655 feet (200 meters). Once it nears the surface again, it can flap its tail and taxi without fully returning to the water. Capable of continuing its flight in such a manner, flying fish have been recorded stretching out their flights with consecutive glides spanning distances up to 1,312 feet (400 meters).

Flying fish are attracted to light, like a number of sea creatures, and fishermen take advantage of this with substantial results. Canoes, filled with enough water to sustain fish, but not enough to allow them to propel themselves out, are affixed with a luring light at night to capture flying fish by the dozens. There is currently no protection status on these animals.

article by : http://animals.nationalgeographic.com/animals/fish/flying-fish.html

Butterfly Fish

One of the most beautifully colored of all fishes, the butterfly fish is well known for it ability to gracefully move about the coral reef with an air of total indifference. Their tightly compress bodies display an array of various patterns and colors that have made them very popular for aquarium use. With close to 115 species of butterfly fishes they can be found in tropical waters among the reef in areas throughout the world but most often observed in the Indo-Pacific regions. They are small to medium fish from the Perciformes order and in the Chaetodontidae family. Of the ten genera in this family the Chaetodon genus contains the majority of the species. The mouth on the butter fly fish is small and protrudes, even extensively in some cases such as the long nose butterfly fish. They have many small teeth in both jaws and the round, flat body of the butterfly fish is, in most species, covered with contrasting colors. The main diet of the butterfly fish consist of algae, plankton, worms and small crustaceans but in many species this fish is considered an omnivore, which means it will eat almost anything that is available.

It is not uncommon to see certain species of the butterfly fish that have several distinct colors or shades of color on their bodies. Although shades of yellow are predominate in many of the species others are found with shades of orange, browns, blues, whites and silver. In most species the body is barred with lines running in various different patterns that give each species its distinction and some species have a single black spot either on the body or fins. This type of marking can be found on the Chaetodon auriga's fin, the body of the Chaetodon capistratus and Chelmon rostratus. One of the more interesting barred species is the Chaetondon vagabundus which has a distinct black bar that runs the width of its body right through the area of the eye. Some of the more colorful of the species might include the blue striped butterfly fish, the Chevron butterfly fish, the forcep fish, the Heni, the half yellow butterfly fish, the jack knife and the Hawaiian teardrop butterfly fish.

Racoon butterfly

Little is known about the mating and reproduction habits of the butterfly fishes although it is known that these fish swim about during the day light hours searching for food. At night they hide among the recesses found in the reef. Most species prefer to live singly or in pairs even though some species are known to live in small schools of no more than ten or twenty of their species. In some species such as the Chaetodon ephippium the eggs are contained inside the body of the female until spawning takes place. They are then released to float openly in the water until hatching. The young butterfly fish in most species are very different in coloration from the adults. In some species, such as the Holacanthus tricolor, the bodies are one solid color with few markings while in others, such as the emperor angelfish, the juveniles are blue with white markings. Aquarium enthusiast throughout the world find the butterfly fish one of the most colorful and beautiful additions to their tanks but it is interesting to note that some species that are equal in size are known to fight with each other. Properly cared for the butterfly fish can survive for many years in an aquarium environment but because they are very sensitive fish, should not be expected to spawn while in captivity.
article by : http://www.essortment.com/all/butterflyfishp_rzqh.htm

Dolphins: The most exciting sea creature

Dolphins are the most attractive sea creatures. When we are alone traveling through ship in the midst of ocean, they are always there running ahead of our ship as if trying to tell they can swim faster than our ship.
Dolphins are not fish, they are mammals. They are warm blooded like man and give birth to one baby called a calf at a time. At birth a bottlenose dolphin calf is about 90-130 cm long and grows to approx. 4 mts. They live up to 40 years. They are highly sociable animals. They are always found in group playing with each other and communicating with each other, thereby producing lovely sound.

Dolphins use their powerful tail flukes in an up and down fashion to move through the water. They also use their tail while hunting, hitting a fleeing fish up into the air, stunning it, and then scooping the fish up when it falls back into the water. They slap their tail rapidly when they get annoyed or when they want to indicate the sign of danger to alert other dolphins. Their teeth are interlocking rows of conical pegs, suitable for holding slippery fish. They eat their fish whole starting with head first. When they go wild they keep their mouth open and sometimes keep their nodding to express their aggression. Greater aggression is shown by violent jaw clapping. Dolphins breathe through their blowhole located at the top of their head. A dolphin may empty and refill its lungs in less than a fifth of a second. As the dolphin breathes, the air leaves the blowhole at speeds of over 100mph. Complex nerve endings around the blowhole sense pressure changes so the dolphin knows exactly when the blowhole is in or nearing the air and can be opened.

The dolphin's eyes produce a special slippery secretion which protects the eyes from foreign objects and water friction. While sleeping, it shuts down only half of its brain, as its breathing is under voluntary control. Dolphins take short cat-naps, floating just below the surface, and then slowly rising to breathe. Often dolphins are very active during night time, for some this is their main feeding time. The dolphin's skin is completely smooth allowing the dolphin to move easily through the water, and also reduce heat loss. Their skin may bear rake marks from other dolphin’s teeth during play or mating, and can easily become badly sun burnt if they strand. Their bodies are very streamlined so they may swim at high speeds through the water, and an example of this is their ears. Dolphin's ears are barely noticeable marked only by a small hole just behind the eye. In a bottlenose dolphin the ear is about 5-6 cms behind the eye and only 2-3 mm in diameter.


Dolphins are able to dive to great depths, and also leap to great heights. They may leap to avoid predators or to show how powerful they are to females at mating time. Bottlenose dolphins can dive to depths of over 1,640 ft (500m). Dolphins carry their young inside their womb and gestation is about 12 months for a bottlenose. The baby emerges tail first, and will suckle from its mother for up to 4 years. The baby will however stay with its mother for between 3-6 years, during which time it learns all about feeding techniques, social interaction and group foraging. Females stay within the family pod with their mother and sisters, though males leave and form associations with other males. They interact with dolphins from other pods from time to time. If any dolphin is drowning, other dolphins will come to its help, supporting it with their bodies so its blowhole is above the water allowing it to breathe.

Dolphin’s are mainly hunt down by sharks and unfortunately man, through direct killing for food, netting, pollution, and fishing. Dolphins spend a large part of their day looking for food, or actually feeding. They may either hunt alone or together as a pod. They use their echolocation to locate fish by sending out a stream of pulses and clicks. When a baby is first born, some dolphin research suggests a mother dolphin will whistle to it constantly, imprinting her sound on the baby so it will recognize her, and the baby learns to develop its own signature whistle. It is thought that each dolphin has its own individual signature whistle, just like a name.

The awareness of saving it from getting extinct is now being recognized and suitable actions are being taken. Australia and several other countries it is now illegal to catch or import any more dolphins for captivity. Dolphins are gifted with power that makes us enthusiastic about them. They must be allowed to leave their life without human interruption.

http://www.buzzle.com/editorials/7-25-2004-57066.asp

author by : http://www.buzzle.com/authors.asp?author=957

Shark: The King Of Water World

They are one of the few individuals that survived themselves from being extinct. Many think that shark is cruel in nature but the fact is that there are only few out of 350 species of sharks that are considered dangerous: the great white shark, tiger shark, bull shark and oceanic white tip shark.

They can survive in all the weather conditions from cold to temperate waters. They are also found in water bodies with temperatures around 90 degrees Fahrenheit. Almost all sharks are carnivores and eat seals, dolphins, sharks and other fish. They are classified into cold-blooded animals. This means that their bodies change temperature as the water temperature changes. Sharks have a body structure of sleek, streamlined design which supports them to swim without using up a lot of energy. This is very important because they don’t sleep and most of them continue their journey without sleeping.

God always provide every creature an ability to defend itself from enemies and so sharks have skin like the spiky suit of armor. Just as the teeth in their jaws are replaced after certain period of time and same as spiky teeth on their body are also changed. Throughout the life the sharks have supply of teeth. In a year an adult shark goes through 7 to 12 sets of teeth. In order to satisfy their needs different species of sharks have different types of teeth. Sharks do not make use of their teeth to chew. They gulp down things whole or in big pieces. The most common shape of teeth of sharks is plate-like triangular one.

They are provided with six senses which make them very well equipped to have their prey. The six senses which shark use very effectively for searching and hunting their prey are vision, vibration, hearing, smell, taste and electro-perception. A shark with its ampullae’s can sense vibrations in the water and will fly through the water straight to the source. Shark has very sensitive nostrils and can find its prey even of small size with great accuracy. They rest during the day time and go for their hunt at the evening and dark hours. As per survey in a zoological environment they eat about 1 % to 10% of its total body weight per week.

Mating of Sharks

The mating actions change as per their size. In smaller species the male curls around the female. In larger species the male arranges himself parallel and in line with the female. Males of many species during mating bite females on the pectoral fins or the middle of the back to hold onto them. Females often bear wound or marks after mating. A close look at these marks shows that they have been made by upper jaw teeth. In some blue shark female sharks, the skin on the back and flanks is double as compared to those of males. Fertilization of Shark and batoid eggs takes place within their body. For energy-intensive reproduction, internal fertilization is a key adaptation.

After the birth young sharks are fully formed and physically able to survive themselves. The number of sharks found in a group usually does not go beyond 100 since the sharks can survive on their own even when they are very young. Clasper is the name given for modified inner edges of the pelvic fins of male sharks. While mating, the straight claspers are bent forward. The male puts in one clasper at a time into the female. The muscles cause seminal fluid down a groove in the clasper and into the female oviduct.

At a time depending on its species, sharks have from 1 to 100 pups. Some sharks lay eggs while other give birth to live pups. Some sharks do not worry about their pups after they are born, although they will search out safe places, where they can lay eggs or give birth. Many pups swim near to shore to grow up on their own. They require 10 to 15 years to grow fully and have an average life span of 100 years.

More time humans spent in their world, the more trouble is cause to them. Human beings should not interfere in their world doing so causes harm to both. A shark is the creativity of God and we should respect their power.

http://www.buzzle.com/editorials/8-9-2004-57651.asp

by: : http://www.buzzle.com/authors.asp?author=949

A Wonderful Fishy World

Have you ever stopped to take a look at the world that a fish lives in? For us it’s such a dark and mysterious place but that is not all that captures us, it is the fact that the fish not only live but also thrive in such an environment. But how do they do it? How do they manage?

Well let’s see, shall we?

Everybody knows that fish have gills. The gills are what make it possible for the fish to breath under water, every gill is made up of curved arches of cartilage on this cartilage are little gill filaments which , to make a long story short, allow the water to pass next to tiny capillaries which absorb the oxygen. Everybody knows that, at least I hope everybody knows that, it is basic fish knowledge.

Something that maybe fewer people know is the fact that fish have a swim bladder; this is the organ that allows the fish to stay in one place without having to tread water as we do. The swim bladder does this by filling up with oxygen from the blood stream. How does it get the oxygen out of the blood stream? There is a little organ attached to the side, this is what collects the oxygen and inflates the swim bladder. Up until now you might say…boring, but did you know that it is because of the swim bladder that the fish can go to depths of up to seven thousand feet or more?

Every diver knows the fact that when you swim up and down in water that deep you have to pressurize or depressurize yourself (or you would either explode or implode); fish manage to do this with the swim bladder, by pressurizing the fish is able to go to depths that we can't even dream of, our little fishy has to take care though and not try to go about pressurizing and depressurizing too fast or he could seriously injure himself, even to the point of losing his life.

If we take an even closer look at fish and the way that they use their swim bladders, we would find that some fish don't only use it for going into the deep blue sea or to stay in one place, there are fish that use their swim bladder to make certain noises such as the catfish, other fish use their swim bladder to breath out of the water, like the lungfish and of course there are the fish that don't even have swim bladders, they found other ways to stay buoyant...I guess some fish just like to be different.

Talking about different, how many people do you know who can produce their own electricity, with their own body? There are many fish that can do just that, they have special organs that can either produce light or even electricity...this is usually used for predatory reasons but there are some fish that just want to be able to see in the dark.

It is usually the fish that can only be found in the depths of the sea that produce light, and it is a light so strong that it can pierce the thickest night, it can light up places that have not seen light for thousands of years, but like I said, most of those fish have dark intentions on their side because all they are trying to do is to attract a smaller fish so that they can have a good supper. The fish that produce electricity are the electric eel and the electric catfish, they also use their abilities for food. The biggest electric eel can output enough electricity to electrocute a grown man!

Fish are such amazing creatures, you know man thinks that he knows so much about everything, but I think that God is not willing to give up all of His secrets so soon. I believe that there is much more out there to see and to discover. Not just weird fish organs, if we were to stop and take a closer look at the world around us I think that we would be amazed at what we would find.

Yes, fish are amazing creatures!

by: Claudia Miclaus

Sounder and Sonar

SONAR (SOund NAvigation and Ranging) — or sonar — is a technique that uses sound propagation under water (primarily) to navigate, communicate or to detect other vessels. There are two kinds of sonar — active and passive. Sonar may be used as a means of acoustic location.

Acoustic location in air was used before radar. Sonar may also be used in air for robot navigation while SODAR (an upward looking in-air sonar) is used for atmospheric investigations. Acoustic emission measurements can also be made for crack detection.

The term sonar is also used for the equipment used to generate and receive the sound. The frequencies used in sonar systems vary from infrasonic to ultrasonic. The study of underwater sound is sometimes known as hydroacoustics.
Principle of an active sonar - send and return pings.


Sounder and Sonar in the fisheries

The use of sonar and sounding equipment is commonplace in many fisheries vessels. Modern sonar gives the ability to locate schools of fish in the water column and then to position the fishing gear accurately to target the school. The technology is now commercially available to classify the bottom type (e.g. rock, sand, silt) by processing the signal from a depth sounder. This, in conjunction with Global Positioning Systems (GPS), digital charts and personal computers, allows an operator to build a highly detailed three-dimensional model of their fishing grounds over time. When further integrated with information on catches, weather, time and tide, such systems can incorporate much of the information and experience an operator gains over time. Improvements in commercially available sounder and sonar technology will likely continue with the incorporation of more frequencies, higher levels of resolution and a better ability to detect and discriminate fisheries resources for targeting.

For some decades acoustic techniques have been used as a survey tool in estimating the abundance or biomass of fish stocks. Only recently has it been possible to determine, with some confidence, the identity of the fish schools being detected. The CSIRO's multi-frequency towed device (MUFTI) technology is capable of discriminating both fish species and size, and has been used in trial surveys of deep-water species such as orange roughy and blue grenadier. Acoustic biomass-surveys are particularly suited to species were the population aggregates into a small area, such as during spawning. In the case of orange roughy the multi-frequency system has significantly reduced the uncertainty surrounding biomass estimates, and generally improved the assessment of the stocks' condition. Whilst not directly applicable at present, this sort of technology is under continuous development and will eventually flow through to the fishing industry in the future.

The other main acoustic device that will have an increasingly marked affect on fisheries development is the sidescan sonar with its ability to produce detailed maps of the seabed. Sidescan sonar maps the seafloor in a swath either side of the vessel—hence the term 'swath mapping'. Despite the comprehensive look of broad-scale bathymetric charts, most Australian waters are very poorly mapped, with large areas virtually unknown. The directed use of high-resolution swath mapping over the past few years has had spectacular results in the waters around, and to the south of, Tasmania. Examination of swath mapping of the Chatham Rise (east coast of New Zealand) almost doubled the estimated area suitable for orange roughy in the area. Geoscience Australia (GA) is currently undertaking the Seabed Mapping and Characterisation project, which is expected to provide detailed seabed mapping of the entire Exclusive Economic Zone (EEZ). The project will provide data to support Australia's UNCLOS claim to seabed beyond the EEZ and assist in Regional Marine Planning.

LINKS and REFERENCE:
* Fisheries Acoustics Research (FAR) at University of Washington http://www.acoustics.washington.edu/

* "ACOUSTICS IN FISHERIES AND AQUATIC ECOLOGY" http://www.ifremer.fr/sympafae/

* http://www.daff.gov.au/brs/fisheries-marine/info/technology

Deep Sea Fishing Tips

Just as with any other type of fishing, deep sea saltwater fishing techniques are largely dependent on what specifically you are trying to catch. However, the good news is that there are particular tips and techniques that can help you have a better chance of landing your fish of choice while you're out on your deep sea expedition. Though there are a host of targets for deep sea fishermen, a few of the common ones are the albacore, yellowtail, white sea bass, and barracuda. Each one of these requires a specific knowledge and approach to make your deep sea expedition a success.

The albacore tuna can be found in temperate deep seas across the globe. It is distinguished from other tunas by the elongated pectoral fins. The albacore eats primarily small fish, but squid crab and shrimp play an important part as well. When you set out to go deep sea fishing, keep in mind that they are located and caught most often by trolling through an area that offers prime diet and temperature conditions for the fish.


Most often, the environment in the waters off of California and Mexico present an ideal place for the albacore. As a result, most albacore deep sea fishing success comes when they are sought after in those waters. Most deep sea sport fishing boats supply trolling rigs for albacore, but if you prefer to use your own rod, you need to make sure that it is between five and a half to six and a half feet long with a sixty to eighty pound test.

The majority of troll caught albacore are caught on feather jigs with colors depending on the condition. If you decide to use bait when fishing for albacore, the most effective kinds are anchovies or sardines. One of the key things to remember when deep sea fishing is to always be alert and prepared - from the very first cast on. It is often the first baits into the water that are bit. Also, when your boat has stopped, make sure that your line is straight out in front of you - this will prevent tangles.

Another popular target of deep sea fishermen is the yellowtail. Typically found in more tropical waters, there are a number of ways to fish yellowtail. They will take a variety of baits and lures, with squid, sardines, mackerels, and anchovies being the most preferred. One thing to keep in mind when dealing with yellowtail is that they are extremely fast.

You will most likely want to use a kind of jig fishing, which allows you to fish with much heavier line. A thirty to fifty pound test works pretty well. However, when the yellowtail are feeding on or near the surface, they sometimes will take surface iron. Squid is certainly the most effective bait of all when dealing with yellowtail. The specific type of hook and jig that will work best is most accurately determined by certain conditions - such as current, depth, and the typical size of yellowtail in the area.

http://ezinearticles.com/?expert=Daniel_Eggertsen