Aquaviews - SCUBA Blog » coral reefs

New Coral Reefs Discovered in India’s Angria Banks

Nevin — Mon, 21 Jun 2010 16:40:23 +0000

The Angria Banks are a shallow submerged atoll island located 100 miles off the western coast of India. For decades the existence of this shallow has been known by mariners navigating India’s coastline who steer clear from this navigational hazard, which lies just 20meters from the surface of the ocean. But it was only recently that the Angria Banks have been researched and explored by Marine Biologists to conduct a feasibility study as to make the area as a destination for marine tourism.

In 2008 the government of India announced a large research grant to to determine the feasibility of further marine tourism in the area with the expectation that the banks contained extensive coral reef that may provide habitat for variety of fishes that could make the area one of India’s best recreational diving destinations.

In a recent Times of India article, India’s Union department of science and technology (DST), conducted a two-day exploratory study of the Angria Banks with five scientists to document and survey the area which spreads over 400 km and only 20 meters below the seas surface. The sea floor surrounding this bank is about 100 feet deep and suddenly rises to just 20 meters The lead scientist Sarang Kulkarni noted that he could not believe the marine wealth that existed there, and claimed it could easily be the largest discovery of coral reef in the entire country because the area is as big as the size of Mumbai which is one of India’s largest cities. The scientists documented at least 1,000 varieties of fish species, and coral life including Great White Shark that inhabit the waters.

This find is great news for scuba divers and a place to watch out for as a prime future scuba diving destination. Its close proximity to the Indian Subcontinent means that the sites are accessible from major Indian cities like Mumbai and Goa with a four hour, high speed boat ride. However to fully appreciate the Angria Banks one would still have to have a liveaboard as there is so much unknown about what treasures and marine wealth inhabits this underwater oasis. Currently however there are no major dive centers offering recreational diving though some may arrange for trips on request. The researchers are pushing the Government to declare the Angria Banks as a protected marine reserve and develop scuba tourism and protect the region from fishing trawlers. So we will simply have to watch and wait to see if the Angria Banks emerges into a prime scuba destination.

Photos from flickr.com by Mr eNil

Visual Indicators of a Healthy Reef

Nevin — Thu, 22 Apr 2010 04:43:07 +0000

A healthy reef ecosystem is usually buzzing with activity, vibrant colors and is host to several different species of fish and invertebrates of all sizes that make the reef their home. Marine conservationists spend a great deal time and use several different techniques to constantly assess the reef conditions. As a diver interested in the quality of the reef and its inhabitants, you don’t need to carry out an in-depth study to gauge the general health of a coral reef. By simply observing certain key indicators, the presence or absence of certain reef inhabitants at different levels in the food chain, one can guess how healthy a reef is.

Abundance of Herbivorous Fish – Parrotfish, Surgeonfish and Tangs
The first good sign of a healthy coral reef is the abundance of Herbivorous Fish primarily Parrotfish and Surgeonfish. Herbivorous fish keep algae populations in check which often compete with the corals for sunlight, nutrients and space. While there are several species of algae eating herbivorous fish, the reason these two species are the ones to look out for is that Parrotfish usually eat the harder, calciferous algae which most species do not prefer. Surgeonfish and Tangs tend to graze on the softer algae allowing existing corals thrive. So spotting plenty of parrotfish and Surgeonfish on a dive would be a good indicator that the reef is doing well.

Sea Urchins
Sea Urchins are a strange indicator of a healthy reef system as they can be both beneficial and harmful to a coral reef depending on their numbers on a reef. Urchins are often known as the lawnmowers of the sea as they feed on a wide variety of marine algae and sea grasses, which helps slow-growing corals to compete for limited reef space. Areas of coral reef that have seen the absence of sea urchins, have gradually gone into decline with uncontrolled algae growth. However the abundance of Sea Urchins can also cause the complete elimination of algae and sea weed robbing the nourishment that mollusks and herbivorous fish rely on also causing the destruction of the reef. Spotting a reasonable amount of sea urchins would signify a fit reef.

The Presence of Large Fish & Apex Predators
The largest fish on a coral reef in decline are usually the first to go. The presence of Barracuda, Jacks, Grouper, Snapper and large Potato Cod, Napoleon Wrasse which are the predators in the food chain, indicate that there is a healthy balance of fish in the reef. Even the Herbivorous fish should have a good number of large sized adults and not just juveniles which indicate poor reef conditions. Octopuses are primary predators on clams and shellfish and their presence in the reef also signifies a healthy shellfish population. If the reef has numerous smaller fish, and no larger pelagic, or adult carnivores, it is a sure sign that the reef is either in decline or recovering from a decline.

Sharks
Sighting sharks in a reef is a prime indicator that the ecosystem is thriving. Reef Sharks, Black-tip white tip or grey sharks, keep the larger fish populations in check and form the Apex predators of the reef ecosystem. The absence of large-bodied predators at the apex of marine food chains can result in large-scale changes in the abundances of other species and cause an imbalance in the reef. So sighting a shark is a good sign that things are well on the reef.

Abundance of Giant Clams, Conches, and Molluscs
What makes Giant Clams a good indicator of a healthy reef is the fact that these endangered creatures are highly sensitive to changes in the water acidity and temperature and perish were conditions are less than perfect. Giant Clams are of vital importance to the reef as they act as nurseries for a host of fish and invertebrates as well as shrimp. Clam shells provide the perfect substrates for attachment for several species of sponges, coral and algae which promote the development of the reef. Clams, conches and molluscs are also filter feeders – sifting plankton debris from the water for food, improving overall water quality in the reef. Smaller grazer molluscs like Abalone and snails also help keep algae growth in check.

The Absence of Coral Bleaching & Diseases
The absence of bleached white coral and signs of coral diseases such as white spot and black bands on coral faces indicate a healthy reef. Coral is highly sensitive to climatic and ocean changes, and when stressed due to changes in water temperature or acidity results in bleaching. Usually a good balance between various varieties of coral, both a combination of soft and hard coral signifies a thriving reef. (Read: Coral Diseases)

So the next time you go diving or snorkeling on a reef, keep an eye out for the presence of these key reef health indicators: parrotfish & surgeonfish, Long spine Urchins, clams, Snapper, barracuda and reef sharks. A combination of these will tell you right away that you can expect to return to this reef to dive again next year.

photos from flickr by: Nataraj Metz, Borneo-Aquanerds, Philippe Guillaume, laszlo-photo, WIlly Volk, pierre pouliquin

Flower Garden Banks National Marine Sanctuary, Texas

Nevin — Thu, 12 Nov 2009 17:38:04 +0000

110 miles of the coast of Texas in the northwest part of the Gulf of Mexico lies atop of underwater mountains called salt domes, the Flower Garden Banks National Marine Sanctuary. Forming one of the 14 designated underwater areas protected by the federal government, the Sanctuary covers 56 square miles or 146 sq kilometers comprising of two areas, the East Flower Garden, the West Flower Garden and the Stetson Bank. Each of these large salt domes which rise up just below the surface of the water are teeming with a wide variety of coral and marine life that have made this area their home over the centuries, and are now considered one of the most pristine untouched reefs in the Caribbean.

The area was originally nick-named by snapper fisherman as the“Texas Flower Gardens”, due to the colorful coral that was visible from the surface and chunks of colorful coral and sponges that were snagged by the lines and nets of fisherman in the area. In 1992 the two larger reefs, the East Flower Garden and the West Flower Garden were designated National Marine Sanctuaries, and the third, the Stenton Bank in 1996.

Home to over 21 species of coral, 170 species of fish and over 300 species of reef invertebrates, the Flower Garden Banks National Marine Sanctuary is a utopia for Scuba Divers. The East and West Flower Gardens are teeming with large boulder corals, primarily brain and star corals, and have several large rays, skates, manta rays, whale sharks and loggerhead turtles. Dive boats can anchor to the one of 5 buoys in the area, and if you anchor to the crest of the salt dome, a diver can swim in any direction and explore the 360 degree fields of coral. Depths in the Sanctuary range from a shallow of 20m (65 feet) to 130m (424ft) deep with Visibility ranging from 75-150 feet (23-45 m).

The Stenton Bank is a smaller dome, with four buoys to anchor to, located much closer together. The water gets deep fast as the coral banks drop off sharply into the Gulf and has only 1 percent of its total area within the recreational diving limit of 130 feet (39 m). However the Stenton Bank has been described by scuba divers as akin to diving on the moon. Eel, urchins, shrimp, lobsters and shellfish are numerous, and the occasional Manta Ray or turtle gliding by isn’t uncommon. Other large fish such as scorpionfish, barracuda, jacks and groupers are found everywhere.

There are several commercial dive charter operators take divers out to the Flower Garden Banks but two boats that regularly set course to Flower Garden Banks National Marine Sanctuary,are the M/V Spree and the M/V Fling 100ft both liveaboards that arrange 2-3 day excursions from Freeport Texas that can carry groups of up to 28 divers. The dives at the Texas Flower Gardens are recommended for intermediate and advanced divers owing to the steep drop-offs and varying depths, no special scuba diving equipment is necessary to dive at the site.

photos by: NOAA’s National Ocean Service

Coral to be Cryogenically Frozen for the Future

Nevin — Wed, 28 Oct 2009 07:47:15 +0000

Corals from tropical oceans around the world are being placed in deep freeze at a British Zoo to preserve them against extinction for future generations owing to the rapid destruction of coral due to increase in greenhouse gas emission levels.

Research has shown that by 2040 almost all of the worlds coral reefs will be dead, wiped out by the rising oceans temperature and increasing acidity levels caused by rising CO2 levels in the atmosphere. The ZSL or the Zoological Society of London is planning the world’s first “Coral Cryobank” where thousands of samples of coral of every species will be cryogenically frozen at -200 degrees centigrade in liquid nitrogen.

Whipsnade Zoo in Bedfordshire has been identified for the new location of the Global Coral Cryobank, where an attempt to store samples of every species of coral on earth is to be made. There are currently over 1800 known tropical corals and around 3,350 cold water species. A Recent scientific breakthrough in regenerating coral from frozen samples is what led to the creation of the Cryobank.

In the wake of rising concerns over the destruction of reefs across the world, and studies made by scientists by observing the effects of the rising CO2 levels on the Great Barrier Reef in Australia, have led many to believe that the gradual destruction of reefs across the world is inevitable. This month 120 legislators from across 16 countries will meet in Copenhagen to discuss how to prevent the destruction of reefs and marine ecosystems and preserve marine ecosystems. The move by the ZSL in the creation of the new coral cryobank is a ground-breaking effort to preserve coral reefs and an example that will be followed by many others. The Smithsonian Institute in Washington is already considering a similar preserve for coral along the same lines as the ZSL, in order to protect coral reefs for future generations.

* Photo credits: Photos by only_point_five, utnapistim on flickr

Playing With Fire Underwater: Fire Coral Demystified

Nevin — Sat, 19 Sep 2009 14:46:19 +0000

What is Fire Coral?

Most Scuba divers who have dived in tropical or sub-tropical reefs will have been cautioned about getting stung by the notorious Fire Coral, and will have filed away the information as just one of the many things that can sting or harm you underwater.

Fire Coral also known as Stinging or Red Sea Coral belongs to the Milleporina order of species and contrary to popular belief isn’t really a coral at all. Fire corals are marine organisms that form colonies that look just like real coral; they are actually closely related to the jellyfish family and other stinging anemones. The Fire Coral gets its name from the painful burning sting that it inflicts on the unwary diver that brushes against it.

How does it look? How can I identify Fire Coral?

Fire Coral is unfortunately rather polymorphic and can appear in several physical forms. Sometimes it appears heavily branched and delicate in appearance, other times it is more, fan-blade shaped and massive. Most common forms it appears is either branched, plated, or encrusted. It is believed to have close to 50 varieties of Fire Coral species making it rather hard to describe. Most of the time Fire corals have a bright yellow-green and brown skeletal covering fading to a whitish hue at the tips, and will be soft and hairy and rounded up close.

Where does it exist?

Fire Coral are widely distributed in tropical and subtropical waters. Primarily occurs in the Indian and Pacific Oceans.

Fire corals form extensive outcrops on projecting parts of the reef where the tidal currents are strong. They are also abundant on upper reef slopes and in lagoons, and occur down to depths of 40 meters.

What does it Do?

Fire Coral belongs to the family of Milleporina, Millepora means ‘many pores’. Upon close inspection, the coral appears to have long fine hairs that protrude from the skeleton. The hairs possess clusters of stinging cells (nematocysts) that inflict the stings on human skin. These hairs capture prey, and help feed the coral.

Divers often mistake fire coral for sea weed or normal coral and may brush against it or lean on it for support. Upon contact the very small nematocysts on the corals hairs release toxins while the sharp calcified exo-skeleton cuts the divers’ skin. A fire Coral sting can cause intense pain and can be felt from two days to up to two weeks. The degree of pain varies on the duration of contact and the number of nematocysts that entered the wound.

Prevention

The best method of prevention is to practice and master Buoyancy control and avoid unnecessary contact with any coral. Wearing full wetsuits & diving gloves is a good way to ensure you don’t accidentally get in contact with Fire Coral.

What do I do if I get stung?

The first step is to rinse the wound or affected area with salt water, as fresh water will increase the pain. Secondly use vinegar (acetic acid) or Isopropyl Alcohol to kill any remaining stinging cells clinging to your skin and help break down the toxin. Use tweezers to put out any stinging hairs. Immobilize the affected limb to prevent spreading and Finally, apply hydrocortisone cream as necessary to reduce inflammation. It is also critical to watch the wound for infection, which will have to be treated with antibiotics by a doctor.

If the diver displays symptoms like shortness of breath and swelling of the tongue, neck and face, he has probably developed an allergic reaction to the sting and should be treated for allergy and rushed to a hospital.

Photos by: Nick Hobgood, Tim Sheerman-Chase, Scary Cow, welshcathy, Paul and Jill, Craig Grobler

Understanding the Different Types of Reefs

Nevin — Tue, 01 Sep 2009 15:13:27 +0000

Reefs are often referred to as the rainforests of the oceans, often playing host to an extraordinary variety of marine plants and animals. Here is a brief compilation of the different kinds of reefs you may encounter on your dives which may help broaden your knowledge of this hobby and help you appreciate the reef ecosystems all the more.

I . Biotic Reefs

Biotic Reefs are created through natural processes and comprise primarily of Coral Reefs and Oyster Reefs.

Oyster Reefs

Oyster reefs are often referred to as oyster bars and are common submerged habitats in the found in near shore areas and estuaries, but grow especially vigorously near river mouths where waters are brackish and less than 10 meters deep. Oysters reproduce and settle on the shells of other oysters and thus, over time, the oysters may form massive reef structures consisting of staggering numbers of individuals. These Oyster reefs play host to several species of breeding fish, smaller organisms and snails often forming a complete microhabitat.

Coral Reefs

Coral reefs are the most popular form of biotic reefs found in the world today, which are formed with a combination of the growth of coral and algae. Corals need warm water between 18°C and 30°C and bright sunlight. Most coral reefs lie between the latitudes of 30 degrees north and south where sea temperatures are warmest. There are three main types of Coral Reef: Fringing, Barrier Reefs and Atolls.

Fringing Reefs

A fringing reef is a submerged platform of living coral that extends from the shore to the sea. It is the most commonly found type of coral reef that can develop in shallow waters (usually 10m) along the coast of tropical islands or continents. The corals grow upwards to sea level or just below and outwards towards the open ocean. Fringing reefs are generally narrow platforms a short distance from shore and don’t contain a substantial lagoon. Fringing reefs are also formed on top of a harder substrate material like limestone or volcanic rock.

Barrier Reefs

A barrier reef is a fringing reef that is separated from the mainland or the island by a deep lagoon. Corals grow on both the calm waters of the lagoon as well as the seaward reef front. The most popular Barrier Reef is Australia’s Great Barrier reef that is the largest reef system in the world. The other popular barrier reef is the Belize barrier reef which is the second largest in the world stretching from Mexico along the coast of Belize to the Bay Islands of Honduras.

Atolls

An atoll is a circular barrier reef forming an island that encircles completely or partially a central lagoon. Parts of the reef may emerge from the water as small islets. It is said that atolls form due to the gradual sinking of oceanic islands over thousands of years. The fringing reef around the island gradually grows as the central parts crumble and build onto the edges, forming a barrier reef until the central portion is completely submerged thus emerging a circular atoll.

II . Abiotic Reefs

Abiotic reefs are a result of a manmade/non living process either influencing the creation of the reef, such as erosion, sand depositing, dumping rocks, underwater blasting etc. Abiotic reefs also consist of Artificial Reefs created with the intent to break waves, reduce erosion or increase the bio diversity promoting marine life in areas of generally featureless bottom. Shipwrecks and sunken oil rigs also contribute to the formation of Abiotic Artificial reefs. Often artificial reefs are created deliberately for diving, but double as reef conservation measures as well by creating a habitat for reef creatures.

photo courtesy: sarsifa, hugginfthecoast.com food blog

5 Stunning Coral Reefs of the World

Noreen — Tue, 11 Aug 2009 07:01:13 +0000

Coral Reefs are huge Scuba Diving attractions. Brilliant colors like pinks, purples, yellows and reds stand out against the hues of blue. Shoals of brightly colored fish dart in and out of the different type of coral, sea anemones, sea urchins and sponges.These ecosystems are the forest of the Oceans and 25% of all marine life reside in these reefs. The rich colorful environment of coral reefs, along with it’s wealth of marine life make it the most popular type of diving destination to explore and discover. Here’s a take of the most stunning Coral Reefs and Reef areas in the World-

1. The Great Barrier Reef: The most popular and largest reef in the world, the Great Barrier Reef is situated off the coast of Queensland, Australia. Contrary to belief it is not one big coral reef but is composed of over 2,900 individual reefs and 900 islands that stretches over 3,000 kilometres (1,600 miles) over an area of approximately 344,400 square kilometres (133,000 sq miles). Seen from space and rated on of the 7 wonders of the World, its no wonder it’s a Top Dive destination.
The Barrier reef displays over 30 species of whales, dolphins and porpoises . Turtles, dugongs, sea snakes and sharks among over 1,500 species of fish and 400 species of coral have made these reefs their home.

* Photos by In Veritas Lux on flickr (top) Eulinky on flickr(bottom)

2. Belize Barrier Reef: The second largest coral reef system and almost as popular as the Great Barrier Reef is the Belize Barrier Reef. Roughly 300 meters (1,000 ft) offshore in the north and 40 kilometers (25 miles) in the south of Belize is the Coral Reef stretching 900 kilometers (560 miles) long. The Belize Reefs attract close to 130,000 visitors to the Country of which scuba diving an snorkeling are very popular.

Part of these reefs is the ever famous Belize Great Blue Hole, a large underwater sinkhole almost perfectly circular in shape, over 300 meters (984 ft) across and 125 meters (410 ft) deep. It’s rated one of the Top 10 Dive Sites in the World and a Must Dive on most diver’s list of dive destinations.

* Photo by Lauretta Burke, World Resources Institute Staff on flickr

3. New Caledonia Barrier Reef: Located in New Caledonia in the South Pacific is the second longest reef after the Great Barrier but isn’t as popular as the Belize Barrier Reef. Reaching a length of 1,500 kilometers (930 miles), the reef encloses a lagoon of 24,000 square kilometers (9,300 sq miles). The average depth of the reefs are about 25 meters (82 ft).

Much of the enormous 1,000 odd species diversity in New Caledonia is yet unclassified as new species of fish and invertebrates.The reefs provide one of the main nesting sites for the Green turtle and is a popular place to spot the rare dugong.

4. Andros, Bahamas: Affectionately known by Bahamians as the “Big Yard”, the largest island in the Bahamas, Andros is home to the third largest Barrier Reef in the World. The Reef extends over 140 miles (230kms) long.

The Island offers some exciting diving of a different kind.Wall diving and Blue hole diving. The island sits on the edge of the steep oceanic trench called the Tongue of the Ocean. This means that when you dive off one side of the island you don’t see a long low reef, but an underwater wall which goes down and down to 6000 feet. The island’s blue holes are water filled cave systems which are very popular dive sites. They attract cave divers from all over the world to dive sites such as ‘Stargate’, ‘The Guardian’ and ‘Little Frenchman’.

* image- fundensity.com

5. Red Sea Coral Reef: Located off the coast of Israel, Egypt and Saudi Arabia, the Red Sea features extensive shallow shelves, noted for their marine life and corals. The fringing reefs are said to be 5000-7000 years old and are largely formed of stony acropora and porites corals.

The reef stretches 2,000 km (1,240 miles) along the coastline and have a rich and diverse ecosystem found nowhere else. 10% of it’s 1,200 species of fish are found only here. Sharks are a common sighting and over 44 species are recorded in the Red Sea. The Dahab Blue Hole is part of this Coral Reef and a very popular dive site.

Coral Reefs Found in Deep Scotland Waters

Noreen — Mon, 10 Aug 2009 13:13:46 +0000

Five previously undiscovered cold-water coral reefs have been found in the deep waters off north west Scotland during a recent research survey commissioned by the Joint Nature Conservation Committee (JNCC). For the first time, these five colourful coral reefs, teeming with strange and beautiful creatures, were captured on film.

* Extract Source: JNCC Press Release – Crown copyright material is reproduced with the permission of the Controller of HMSO and the Queen’s Printer for Scotland

News of the discovery of thriving coral reefs along the coast of Scotland in the Atlantic comes as a bit of a surprise but with some amazing promise to learn more about cold water reefs. Found at shocking depths of up to 1,500 metres by a team from the government’s Joint Nature Conservation Committee (JNCC), the unveiling of these reefs have shed a little more light on the relatively unknown deep water coral reefs.

*Image by Nick Hobgood (Nhobgood) on wikipedia.org

Coral formations have been often associated with tropical climates. With over 284,300 square kilometers of Coral reefs in the Indo- Pacific region including the Red Sea, Indian Ocean, South East Asia and the Pacific, they are said to account for 91.9% of the total reefs around the world. Little is known about deep water coral as the discovery of this type of formation has mostly come from fishing companies and other organizations.

The Deep Water Coral Reefs discovered a mile down of the Scottish Coast are reported to be over a meter high and boast of a wealth of marine life and possible new species lurking in the depths. Judging from the slow growth of cold water coral due to relatively less sunlight and it’s deeper location as compared to the tropical variety of coral, these reefs have probably taken centuries to form.

The team is said to have taken extensive footage and images of the newly discovered reefs which are in pristine condition, untouched by human impact. Further studies of both the coral and the realm of marine life it holds will help us better understand the nature of this type of coral. The reefs will also be placed under protection with actions from the government based on reports, to ban deep-water bottom trawling especially in the area.

The reefs support a wide diversity of marine life, such as sponges, starfish, sea urchins, crabs, and deep-sea fish including the blue ling, round-nosed grenadier, and orange roughy. WWF and other organizations have highlighted the damaging impacts that deep-water trawlers are having on the corals, with huge areas of the seabed being dredged and scarred.