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    SNOWTGRR   15,110
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CAT Day 4

Thursday, May 16, 2013

Phew! Woke up just in time to go swimming with the Whale Sharks. They are so fascinating! But first a bit about Exmouth.

The town was established in 1967 to support the nearby United States Naval Communication Station Harold E. Holt. Beginning in the late 1970s, the town began hosting U.S. Air Force personnel assigned to Learmonth Solar Observatory, a defence science facility jointly operated with Australia's Ionospheric Prediction Service.

The location was first used as a military base in World War II. After the retreat from Java in March 1942, Allied naval forces had need of a forward base for replenishing submarines, then the sole form of offensive warfare against the Japanese. Both Darwin, Northern Territory, and Broome, Western Australia, were too exposed to air attack, so a 500-ton unmotorized lighter was placed as a refueling barge near the mouth of Exmouth Gulf, where the Allies were already maintaining a seaplane tender. A seaplane tender (or seaplane carrier) is a ship that provides facilities for operating seaplanes. These ships were the first aircraft carriers and appeared just before the First World War.

Code-named Potshot, the spartan base was also developed as an advanced base and rest camp for submariners using the tender USS Pelias. An airfield (now RAAF Learmonth) was constructed to provide fighter defense for the base. Z Special Unit used Potshot as a staging base for Operation Jaywick in September 1943. Operation Jaywick was a special operation undertaken in World War II. In September 1943, 14 commandos and sailors from the Z Special Unit raided Japanese shipping in Singapore Harbour, sinking seven ships.

Z Special Unit (also known as Special Operations Executive (SOE), Special Operations Australia (SOA) or the Services Reconnaissance Department (SRD)) was a joint Allied special forces unit formed during the Second World War to operate behind Japanese lines in South East Asia. Predominantly Australian, Z Special Unit was a specialist reconnaissance and sabotage unit that included British, Dutch, New Zealand, Timorese and Indonesian members, predominantly operating on Borneo and the islands of the former Netherlands East Indies.

Nowadays the town relies more on tourism than the station for its existence. At the height of the tourist season the population swells to 6000. Exmouth is one of the few areas in Australia that can boast the "Range to Reef" experience. The Cape Range National Park which has some spectacular gorges is an area of 506 square kilometres and its main area is focused on the west coast of the Cape which provides a large variety of camp sites on the coastal fringe of the Park.







With that the Whale Sharks are waiting for us. Not really but it would be nice to think so. lol

The whale shark, Rhincodon typus, is a slow-moving filter feeding shark and the largest known extant fish species. The largest confirmed individual had a length of 12.65 meters and a weight of more than 21.5 metric tons, and there are unconfirmed reports of considerably larger whale sharks. Claims of individuals over 14 meters long and weighing at least 30 metric tons are not uncommon. The whale shark holds many records for sheer size in the animal kingdom, most notably being by far the largest living non-mammalian vertebrate, rivaling many of the largest dinosaurs in weight. It is the sole member of the genus Rhincodon and the family, Rhincodontidae (called Rhiniodon and Rhinodontidae before 1984), which belongs to the subclass Elasmobranchii in the class Chondrichthyes. The species originated approximately 60 million years ago.



The whale shark is found in tropical and warm oceans and lives in the open sea with a lifespan of about 70 years. Although whale sharks have very large mouths, as filter feeders they feed mainly, though not exclusively, on plankton, which are microscopic plants and animals. However, the BBC program Planet Earth filmed a whale shark feeding on a school of small fish. The same documentary showed footage of a whale shark timing its arrival to coincide with the mass spawning of fish shoals and feeding on the resultant clouds of eggs and sperm.



The species was distinguished in April 1828 after the harpooning of a 4.6 meters specimen in Table Bay, South Africa. The name "whale shark" comes from the fish's physiology, being as large as some species of whales and also a filter feeder like baleen whales.

The whale shark inhabits all tropical and warm-temperate seas. Primarily pelagic, seasonal feeding aggregations occur at several coastal sites such as the Ningaloo Reef in Western Australia among several others. Although typically seen offshore, it has been found closer to land, entering lagoons or coral atolls, and near the mouths of estuaries and rivers. Its range is generally restricted to about ±30° latitude. It is capable of diving to depths of at least 1,286 meters, and is migratory.

As a filter feeder it has a capacious mouth which can be up to 1.5 meters wide and contains 10 filter pads and between 300 and 350 rows of tiny teeth. It has five large pairs of gills. Two small eyes are located towards the front of the shark's wide, flat head. The body is mostly grey with a white belly; three prominent ridges run along each side of the animal and the skin is marked with a checkerboard of pale yellow spots and stripes. These spots are unique to each individual and are useful for counting populations. Its skin can be up to 10 centimeters thick. The shark has a pair each of dorsal fins and pectoral fins. Juveniles' tails have a larger upper than lower fin while the adult tail becomes semi-lunate (crescent-shaped). Spiracles are just behind the eyes.



The whale shark is a filter feeder – one of only three known filter feeding shark species (along with the basking shark and the megamouth shark). It feeds on macro-algae, plankton, krill, Christmas Island red crab larvae and small nektonic life such as small squid or vertebrates. It also feeds on small fish and the clouds of eggs and sperm during mass spawning of fish shoals. The many rows of vestigial teeth play no role in feeding. Feeding occurs either by ram filtration, in which the animal opens its mouth and swims forward, pushing water and food into the mouth, or by active suction feeding, in which the animal opens and closes its mouth, sucking in volumes of water that are then expelled through the gills. In both cases, the filter pads serve to separate food from water. These unique, black sieve-like structures are presumed to be modified gill rakers. Food separation in whale sharks is by cross-flow filtration, in which the water travels nearly parallel to the filter pad surface, not perpendicularly through it, before passing to the outside, while denser food particles continue to the back of the throat. This is an extremely efficient filtration method that minimises fouling of the filter pad surface. Whale sharks have been observed "coughing" and it is presumed that this is a method of clearing a build-up of particles from the filter pads. Whale sharks migrate to feed and possibly to breed.

The whale shark is an active feeder, targeting concentrations of plankton or fish. It is able to ram filter feed or can gulp in a stationary position. This is in contrast to the passive feeding basking shark, which does not pump water. Instead, it swims to force water across its gills.

Despite its size, the whale shark does not pose significant danger to humans. Although massive, whale sharks are docile fish and sometimes allow swimmers to catch a ride, although this practice is discouraged by shark scientists and conservationists. Younger whale sharks are actually quite gentle and can play with divers.



Neither mating nor pupping of whale sharks has been observed. The capture of a female in July 1996 who was pregnant with 300 pups indicates that whale sharks are ovoviviparous. The eggs remain in the body and the females give birth to live young which are 40 to 60 centimeters long. There is evidence that the pups are not all born at once, but rather that the female retains sperm from one mating and produces a steady stream of pups over a prolonged period. It is believed that they reach sexual maturity at around 30 years and the life span is an estimated 70 to 100 years.

Known as a deity in a Vietnamese culture, the whale shark is called "Ca Ong", which literally translates as "Sir Fish".



After a lovely swim with the Whale Sharks I decided I needed to rest my knee and went on the Ningaloo Glass Bottom Boat. It was so fun and such a learning opportunity.

The Ningaloo Reef is a fringing coral reef located off the north west coast of Western Australia. The reef is 260 km long and is Australia's largest fringing coral reef and the only large reef positioned very close to a landmass.

A fringing reef is one of the three main types of coral reefs recognized by most coral reef scientists. It is distinguished from the other two main types (barrier reefs and atolls) in that it has either an entirely shallow backreef zone (lagoon) or none at all. If a fringing reef grows directly from the shoreline (see photo, below) the reef flat extends right to the beach and there is no backreef. In other cases (e.g., most of The Bahamas), fringing reefs may grow hundreds of yards from shore and contain extensive backreef areas with numerous seagrass meadows and patch reefs.



This type of coral reef is the most common type of reef found in the Caribbean and Red Sea. Darwin believed that fringing reefs are the first kind of reefs to form around a landmass in a long-term reef growth process.



It is known for its seasonal feeding concentrations of the whale shark, and the conservation debate surrounding its potential tourism development. In 1987 the reef and surrounding waters were designated as the Ningaloo Marine Park. In 2011 the reef and surrounding areas were world heritage listed by the United Nations.



The reef is rich in coral and other marine life. During the winter months, the reef is part of the migratory routes for dolphins, dugongs, manta rays and humpback whales. The beaches of the reef are an important breeding ground of the loggerhead, green and hawksbill turtles. They also depend on the reef for nesting and food. The Ningaloo supports an abundance of fish (500 species), corals (300 species), molluscs (600 species) and many other marine invertebrates. The reef is less than half a kilometre offshore in some areas, such as Coral Bay.



In 2006, researchers from the Australian Institute of Marine Science discovered in the marine park’s deeper waters gardens of sponges that are thought to be species completely new to science.

It was so great to see the reefs and different fish under the glass bottom. It also gave those of us who didn't want to snorkel a chance to see the wild life as well.

After we got off the boat it was dinner time so we got a quick meal and hurried to see the turtles laying their eggs!







The loggerhead sea turtle (Caretta caretta), or loggerhead, is an oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the family Cheloniidae. The average loggerhead measures around 90 cm long when fully grown, although larger specimens of up to 280 cm have been discovered. The adult loggerhead sea turtle weighs approximately 135 kg, with the largest specimens weighing in at more than 450 kg. The skin ranges from yellow to brown in color, and the shell is typically reddish-brown. No external differences in gender are seen until the turtle becomes an adult, the most obvious difference being the adult males have thicker tails and shorter plastrons than the females.

The loggerhead sea turtle is found in the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea. It spends most of its life in saltwater and estuarine habitats, with females briefly coming ashore to lay eggs. The loggerhead sea turtle has a low reproductive rate; females lay an average of four egg clutches and then become quiescent, producing no eggs for two to three years. The loggerhead reaches sexual maturity within 17–33 years and has a lifespan of 47–67 years.



The loggerhead sea turtle is omnivorous, feeding mainly on bottom-dwelling invertebrates. Its large and powerful jaws serve as an effective tool for dismantling its prey. Young loggerheads are exploited by numerous predators; the eggs are especially vulnerable to terrestrial organisms. Once the turtles reach adulthood, their formidable size limits predation to large marine animals, such as sharks.

Loggerheads are considered an endangered species and are protected by the International Union for the Conservation of Nature. Untended fishing gear is responsible for many loggerhead deaths. Turtles may also suffocate if they are trapped in fishing trawls. Turtle excluder devices have been implemented in efforts to reduce mortality by providing an escape route for the turtles. Loss of suitable nesting beaches and the introduction of exotic predators have also taken a toll on loggerhead populations. Efforts to restore their numbers will require international cooperation, since the turtles roam vast areas of ocean and critical nesting beaches are scattered across several countries.



It was such a great day. I ended up only taking 911 steps but I have to take it easy on my knee. So I was a good girl today. With all that we did today I'm exhausted. I do know that the sea air makes one tired. I don't know why but it does. So with this I'm going to go watch some Tele and go to sleep.

Patty emoticon









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  Member Comments About This Blog Post:

IKACEY 5/16/2013 4:03AM

    Lovely blog! Lots of factoids and beautiful pictures! The best thing you can do for in pain is take it easier and take your meds. You can work on it more when that knee is recovered. Until then gentle seated exercise and pain meds and distracting yourself, like blogging are all going to be a big help getting thru this emoticon
IKacey co-leader of the Chair Exercise Team

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SNOWTGRR 5/16/2013 1:56AM

    Oops. Sorry about the turtle mix up. emoticon Can I claim pain meds?

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TORTILLAFLATS 5/16/2013 1:28AM

    great blog Pattie

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EMMABE1 5/16/2013 12:54AM

    Great blog - one slight problem - the turtles that mostly lay in that area of West Australia are Flatbacked Marine Turtles - rather than Loggerheads.
We tend to get a lot of Loggerheads on the Eastern side of Australia

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