Blue
sharks are among the most abundant and far-ranging of all sharks,
found in tropical, subtropical and temperate waters of every ocean.
They are known to migrate long distances, and prey primarily on
schooling fish such as anchovies, sardines, herring and squid. Blue
sharks will, however, attack virtually anything, including gill-netted
salmon and wounded marine mammals. Blue sharks were identified and
named by Linnaeus, the father of modern taxonomy, in 1758, and its
common name comes from its dark blue dorsal fin and bright blue
sides. Adult blue sharks weigh between 70 to 120 pounds and can
grow up to five to seven feet long. They are fished commercially,
usually on baited long lines, and by sports fishermen with rods and
reels.
Blue shark's diet
Squids are a important meal plan for the blue shark.Other meal plans are cuttlefish pelagic octopuses,
Monday, November 26, 2012
Saturday, November 24, 2012
Whale shark
As the largest fish in the sea, reaching lengths of 40 feet (12
meters) or more, whale sharks have an enormous menu from which to
choose. Fortunately for most sea-dweller sand us!Their favorite meal is
plankton. They scoop these tiny plants and animals up, along with any
small fish that happen to be around, with their colossal gaping mouths
while swimming close to the water's surface.
The whale shark, like the world's second largest fish, the basking shark, is a filter feeder. In order to eat, the beast juts out its formidably sized jaws and passively filters everything in its pathThe mechanism is theorized to be a technique called “cross-flow filtration,” similar to some bony fish and baleen whales.
The whale shark's flattened head sports a blunt snout above its mouth with short barbels protruding from its nostrils. Its back and sides are gray to brown with white spots among pale vertical and horizontal stripes, and its belly is white. Its two dorsal fins are set rearward on its body, which ends in a large dual-lobbed caudal fin (or tail).
Preferring warm waters, whale sharks populate all tropical seas. They are known to migrate every spring to the continental shelf of the central west coast of Australia. The coral spawning of the area's Ningaloo Reef provides the whale shark with an abundant supply of plankton.
Although massive, whale sharks are docile fish and sometimes allow swimmers to hitch a ride. They are currently listed as a vulnerable species; however, they continue to be hunted in parts of Asia, such as the Philippines.
The whale shark, like the world's second largest fish, the basking shark, is a filter feeder. In order to eat, the beast juts out its formidably sized jaws and passively filters everything in its pathThe mechanism is theorized to be a technique called “cross-flow filtration,” similar to some bony fish and baleen whales.
The whale shark's flattened head sports a blunt snout above its mouth with short barbels protruding from its nostrils. Its back and sides are gray to brown with white spots among pale vertical and horizontal stripes, and its belly is white. Its two dorsal fins are set rearward on its body, which ends in a large dual-lobbed caudal fin (or tail).
Preferring warm waters, whale sharks populate all tropical seas. They are known to migrate every spring to the continental shelf of the central west coast of Australia. The coral spawning of the area's Ningaloo Reef provides the whale shark with an abundant supply of plankton.
Although massive, whale sharks are docile fish and sometimes allow swimmers to hitch a ride. They are currently listed as a vulnerable species; however, they continue to be hunted in parts of Asia, such as the Philippines.
Black tip shark
Social Life and Behavior
This shark species is very social and mostly found in larger groups with a strong hierarchy. Scientists believe a major reason for building groups is because these sharks tend to be very shy and timid towards other predators. Their philosophy is power in numbers.
Hunting Behavior
These are athletic and energetic hunters. They have a spectacular technique in which they catapult their body out of the water and rotate themselves the to four times before falling back into the water. It's unclear why exactly they do this, but it's often associated with hunting. They love to hunt for small fish like sardines and herrings, groupers, rays, and smaller sharks.
Offspring
Interestingly enough, females are able to reproduce asexually if males are not available. They are viviparous, meaning they give live birth to up to 10 pups per year. They reach maturity at an average age of about 4 years old for males and 7 years old for females. Most live to 13 years of age, sometimes longer.
Human Interaction
The Black tip Shark population has remained about even in recent years, even with commercial and game fishing. Their body parts are often used for fish fin soup and are harvested of shark oil, liver, and their flesh is considered a delicacy in many cultures. Since their reproductive rate is slower than most sharks, it's a species of concern.
The attack rate on humans is exceedingly low, but since they often swim in the same areas as people, conflicts have happened. There are no known fatal attacks on humans without provocation. It's important to note that these sharks are easily spooked. When threatened, they form an S-Shape with their bodies and roll from side to side.
This shark species is very social and mostly found in larger groups with a strong hierarchy. Scientists believe a major reason for building groups is because these sharks tend to be very shy and timid towards other predators. Their philosophy is power in numbers.
Hunting Behavior
These are athletic and energetic hunters. They have a spectacular technique in which they catapult their body out of the water and rotate themselves the to four times before falling back into the water. It's unclear why exactly they do this, but it's often associated with hunting. They love to hunt for small fish like sardines and herrings, groupers, rays, and smaller sharks.
Offspring
Interestingly enough, females are able to reproduce asexually if males are not available. They are viviparous, meaning they give live birth to up to 10 pups per year. They reach maturity at an average age of about 4 years old for males and 7 years old for females. Most live to 13 years of age, sometimes longer.
Human Interaction
The Black tip Shark population has remained about even in recent years, even with commercial and game fishing. Their body parts are often used for fish fin soup and are harvested of shark oil, liver, and their flesh is considered a delicacy in many cultures. Since their reproductive rate is slower than most sharks, it's a species of concern.
The attack rate on humans is exceedingly low, but since they often swim in the same areas as people, conflicts have happened. There are no known fatal attacks on humans without provocation. It's important to note that these sharks are easily spooked. When threatened, they form an S-Shape with their bodies and roll from side to side.
Basking Shark
TEETH
Basking sharks have hundreds of teeth (each having a single cusp, curving backwards) but they are tiny and are of little use.
DIET AND FEEDING HABITS
Basking sharks are filter feeders that sieve small animals from the water. As the basking shark swims with its mouth open, masses of water filled with prey flow through its mouth. The prey includes plankton, baby fish, and fish eggs. After closing its mouth, the shark uses gill rakers that filter the nourishment from the water. Gill rakers are bristly structures (the thousands of bristles are about 4 inches or 10 cm long) in the shark's mouth that trap the small organisms which the shark then swallows. The water is expelled through the shark's 5 pairs of gill slits. The shark can process over 1500 gallons (6000 liters) of water each hour.
SOCIAL GROUPS
Basking sharks travel alone, in pairs, or in schools (groups) of up to 100 members.
HABITAT
Basking sharks live in coastal temperate waters. They spend most of their time at the surface, hence their nickname the "sunfish."
DISTRIBUTION
Basking sharks are found off the coasts of western North America from Baja to southern Alaska, off the east coast of the US and southern Canada, along the Gulf Stream, to the entire coastline of Europe, off the southern coast of Australia, off South Africa, New Zealand, most of southern South America, the Red Sea, and the coastlines of China and Japan.
Basking sharks have hundreds of teeth (each having a single cusp, curving backwards) but they are tiny and are of little use.
DIET AND FEEDING HABITS
Basking sharks are filter feeders that sieve small animals from the water. As the basking shark swims with its mouth open, masses of water filled with prey flow through its mouth. The prey includes plankton, baby fish, and fish eggs. After closing its mouth, the shark uses gill rakers that filter the nourishment from the water. Gill rakers are bristly structures (the thousands of bristles are about 4 inches or 10 cm long) in the shark's mouth that trap the small organisms which the shark then swallows. The water is expelled through the shark's 5 pairs of gill slits. The shark can process over 1500 gallons (6000 liters) of water each hour.
SOCIAL GROUPS
Basking sharks travel alone, in pairs, or in schools (groups) of up to 100 members.
HABITAT
Basking sharks live in coastal temperate waters. They spend most of their time at the surface, hence their nickname the "sunfish."
DISTRIBUTION
Basking sharks are found off the coasts of western North America from Baja to southern Alaska, off the east coast of the US and southern Canada, along the Gulf Stream, to the entire coastline of Europe, off the southern coast of Australia, off South Africa, New Zealand, most of southern South America, the Red Sea, and the coastlines of China and Japan.
Hammer Head shark
There are eight different species of Hammerhead shark. All the species
have the remarkable projections on both sides of the head, which
probably is they reason why these sharks can detect electronic signals
of no more than half a billionth of a volt. The head is probably used
during electrolocation. By separating the receptors, the Hammerhead
shark can receive signals in stereo. The oddly shaped head also seem to
act as a wing that the Hammerhead shark uses for close-quarters
maneuverability. The head looks somewhat like a flattened hammer, which
is the reason behind the name of the Hammerhead shark. The nostrils and
eyes are located at the tip of the extensions. All Hammerhead shark
species have proportionately small mouths. The size of the eight
different Hammerhead sharks varies between 2 and 6 meters. The largest
Hammerhead species, the Great Hammerhead shark, will typically weigh
around 230 kg (500 pounds) but can reach a weight of 450 kg (1,000
pounds). Three Hammerhead species can be dangerous to humans: the Great
Hammerhead shark, the Scalloped Hammerhead shark and the Smooth
Hammerhead sharks.
The strangely shaped head of the Hammerhead shark has given raise to a lot of speculation. There are two main theories regarding its development. Some scientists believe that the shape evolved gradually over numerous generations, while others suggest that it was a sudden mutation that rapidly proved to be an advantage. The entire head is equipped with sensors, and might be hammer-shaped in order to provide a larger area for the sensors. A larger sensor area would give the Hammerhead shark an advantage when it scans the bottom of the sea for food.
The Hammerhead sharks are probably related to the Carcharhinid sharks which evolved during the mid-tertiary period. It is somewhat difficult to investigate the evolutionary process of sharks, since the bones of sharks aren’t mineralized and seldom fossilize. There teeth are however often found as fossils. The teeth of the Hammerhead sharks are very similar to fossilized teeth from the Carcharhinid sharks. The Hammerhead sharks most likely developed during the late Eocene, Oligocene or early Miocene. It is hard to establish the exact era since it is difficult to know which teeth belong to Hammerhead sharks and which belong to Carcharhinid sharks.
All the Hammerhead shark species belong to the order of Carcharhiniformes, which means that they are ground sharks with one anal fin and two dorsal ones. They fins are spineless and the mouth is located behind the eyes. All Hammerhead sharks have five gill slits and a spiral intestinal valve. The spiral shape means that the food will pass through the intestines at a remarkably slow pace.
The strangely shaped head of the Hammerhead shark has given raise to a lot of speculation. There are two main theories regarding its development. Some scientists believe that the shape evolved gradually over numerous generations, while others suggest that it was a sudden mutation that rapidly proved to be an advantage. The entire head is equipped with sensors, and might be hammer-shaped in order to provide a larger area for the sensors. A larger sensor area would give the Hammerhead shark an advantage when it scans the bottom of the sea for food.
The Hammerhead sharks are probably related to the Carcharhinid sharks which evolved during the mid-tertiary period. It is somewhat difficult to investigate the evolutionary process of sharks, since the bones of sharks aren’t mineralized and seldom fossilize. There teeth are however often found as fossils. The teeth of the Hammerhead sharks are very similar to fossilized teeth from the Carcharhinid sharks. The Hammerhead sharks most likely developed during the late Eocene, Oligocene or early Miocene. It is hard to establish the exact era since it is difficult to know which teeth belong to Hammerhead sharks and which belong to Carcharhinid sharks.
All the Hammerhead shark species belong to the order of Carcharhiniformes, which means that they are ground sharks with one anal fin and two dorsal ones. They fins are spineless and the mouth is located behind the eyes. All Hammerhead sharks have five gill slits and a spiral intestinal valve. The spiral shape means that the food will pass through the intestines at a remarkably slow pace.
Wednesday, November 21, 2012
Thanks Giving Post
The story of the first thanksgiving when the pilgrims invited local native Americans to share a meal with them but I bet you didn't know Thanksgiving didn't become an annual tradition until 200 years later.The first Thanksgiving in 1621 wasn't just a big meal it was a three day festival filled with eating hunting and other entertainment in honor of the pilgrims first successful harvest.The Indians killed 5 deer as gifts for the colonists so Venison was definitely on the the first thanksgiving menu.I bet you didn't know that turkey not,they also didn't have pumpkin pie or potatoes which hadn't been introduced to England yet.While they may have eaten cranberries they would have been served plain not in a sauce or relish.The pilgrims didn't plan on having a thanks giving tradition in fact they didn't repeat the November celebration in many years.In 1789 president George Washington announced the first ever national Thanksgiving holiday which took place on Thursday November 26th 1789 but it didn't become an annual tradition nation wide until the 19th century.Thats when an American writer named Sara Josepha Hale.Most famous for writing the nursery rhyme Mary had a little lamb was inspired by Diary of a pilgrim life to recreate that first Thanksgiving feast.Beginning in 1827 Hale waged a nearly 30 year campaign to make Thanksgiving a national holiday,she also published recipes for pumpkin pie turkey and stuffing that probably didn't appear on the pilgrims plates.but would become the staples of modern Thanksgiving meals.In 1863 in the mist of the civil war president Aberham Lincoln announced that the nation would celebrate Thanksgiving every year on the final Thursday in November.Did you know in 1939 president Franklin D Roosevelt decided to move Thanksgiving up a week to give depressing error realtors more time to make money during the pre Christmas shopping season but that never happened and the Holiday will stay on Thursday November 26th 1789.
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