January 3, 2012 § Leave a comment
Updated January 03, 2012 20:53:48
More than 50 of the hybrid sharks were found in a 2,000-kilometre stretch of coast.
Marine biologists say they have discovered the world’s first hybrid sharks off Australia’s east coast, a potential sign the predators are adapting to cope with climate change.
They say the mating of the Australian black-tip shark with its global counterpart, the common black-tip, is an unprecedented discovery with implications for the entire shark world.
“It was unprecedented because hybridisation between sharks in the wild has never been reported before in Australia or worldwide,” said Dr Jennifer Ovenden from the Queensland Department of Primary Industries and Fisheries.
The scientists were examining fish stocks when they found 57 of the hybrid sharks in a 2,000-kilometre stretch of coast. They are a cross between two related but genetically different species.
The larger common black-tip shark swims in the colder waters of southern Queensland and northern New South Wales, while the smaller Australian black-tip likes warmer seas.
Dr Ovenden says there is a good reason why these sharks interbreed.
“Species with the smaller body can hybridise with the species with the larger body, allowing that tropical species to move further south,” she said.
“We are thinking that it will provide the sharks with a mechanism to adapt to future environmental change.”
Hybridisation happens among many species in the animal kingdom, including birds and some fish, but until now has been unknown among sharks.
Dr Colin Simpfendorfer, director of the Fishing and Fisheries Research Centre at James Cook University, says the discovery will help expand scientific understanding of sharks.
“It’s obviously a very interesting observation because we’ve never seen hybrid sharks before, and so it’s been hypothesised that it’s possible but we’ve never had any proof that it happens,” he said.
JCU fisheries researcher David Welch says it is a remarkable discovery.
“They actually choose a mate. It’s not like a fish where they actually put eggs and sperm into the water and they can potentially mix,” he said.
“Animal species tend to know their own kind, but in this case there seems to be a high prevalence of them interbreeding.”
The scientists are planning to look for hybridisation in other waters, including the western and northern Australian coasts
Sharks play an important role in the health of the marine environment. Sharks are known for being one of the few animals that never evolved over millions of years as they were perfectly suited to the ocean environment and did not need to adapt. However the new hybrid sharks show that global changes have caused the sharks to begin to process of evolution in order to survive.
October 21, 2011 § 2 Comments
One of the largest of flying birds, albatrosses have been described as “the most legendary of all birds”. The Albatross has been the subject of legends and stories for hundreds of years going back to the day of great sailing ships where sailors believed that albatross were the spirits of sailors lost at sea to being the central emblem to the poem “The Rime of the Ancient Mariner”.
The Galapagos Albatross or the Waved Albatross is the only member of the Albatross family that lives in the topics. The Galapagos Albatross is considered endemic to the Island of Española though in recent years small groups have been identified on both on the island of Genovesa and 5 to 6 pairs on Isla de la Plata on the coast of Ecuador. The Albatross arrive on Española each April where they mate, nest and remain through December.
Albatross come back to find the same mate every year until one or the other dies. The mating ritual begins with the couple engaging in a series of beak jousting moves where they circle each other raise and lower and then clack together. They then built a nest typically on the rocky surface. The couple will produce 1 egg per year which is raised in a nursery with other chicks while the parents head out to sea to feed. In December when the chicks are big enough to survive on their own entire colony will head out to sea where they live over the ocean along the coasts of Ecuador and Peru.
Visiting Española you can see the chicks as well as the adults with their giant 6 foot wing span as the fling themselves off the cliff to fish in an area appropriately nicknamed the Albatross Airport.
Andres Baquero, executive director of Equilibrio Azul Foundation, says that a Waved Albatross population is classified as Critically Endangered. The number one threat to the Albatross population is fisherman as the birds confuse the prey on hooks and get caught by fisherman. In a study conducted by the Foundation in Santa Elena, 30% of respondents had seen fishermen albatross their hooks.
“Fishermen are not interested in capturing seabirds in the country, that way no problem,” emphasized Baquero. The sixth meeting of Agreement on the Conservation of Albatrosses and Petrels (ACAP) took place in Guayaquil at the end of August and is looking into new ways to help preserve these majestic birds.
August 15, 2011 § 1 Comment
The authorities of the Galapagos National Park of Ecuador and the operators of the airport in Baltra are seek to find protect the land iguanas living on the island of Baltra.
Victor Carrion from the national park stated today, since July a total of (5) iguanas have been found dead in the airport area, (3) were killed when hit by aircraft, (1) by motor vehicle and the other by activity near the airport. The airport operators have told the park that they will begin an inspection of the runway before any airplane is allowed to land or take off from Baltra in order to protect the iguanas. While the program is new the park authorities believe the efforts will help along with having training pilots on how to protect the iguanas.
Baltra is the busiest of the airports in Galapagos. “Losing five minutes to protect an iguana, I think it’s worth,” said aware of that little time can mean a lot of money for airlines.Carrion noted that during the 1980’s the National Park and Charles Darwin Foundation implimented a iguana breeding program to restore land iguanas to Baltra. In 1932 amateur naturalist G. Allan Hancock capture 20 iguanas from Baltra and introduced them to the island of North Seymour which at the time did not have an iguana population. While this act would be unheard of today his efforts are what allowed the park to initiate the breeding program. The iguana breeding program was successful, Baltra now has approximately 1,000 iguanas. While at one time land iguanas on the island were at the brink of extinction. “There is increasing population of iguanas, the reproduction in the wild is very good,” said Carrion.
“They in certain areas are looking for new areas of life because iguanas are quite territorial and that has forced to take a step just for the airport area,” said the advance that has been advanced in training for staff who are responsible for remodeling terminal and runway.
Thus, workers will know that before getting into the vehicle should be checked, for example, that motor is not under any iguana sheltering from the sun.
August 5, 2011 § 2 Comments
These colorful small creatures are the most abundant reptile in the Galapagos Islands. Living on most of the main islands there are seven different subspecies all endemic to the islands, yet each island has only one type. Ranging from black with gold stripes to greyish yellow to speckled copper the Galapagos Lava Lizards have a different appearance based both on where they are from and their sex. The Lava Lizards which live primarily on the lava will have a darker appearance while those living on a beach will have a lighter appearance allowing them to
blend more easily into the environment, providing a natural protective camouflage. Lava Lizards also have the ability to change colors if they are threatened or if there is a change in temperature.
Feeding on moths, flies, beetles, ants, spiders, grasshoppers and some plants the Galapagos Lava Lizard plays a significant role in the control
of the insect population of the islands. Like the Galapagos Iguanas and other reptiles, the lava lizard relies on the sun’s heat for their own internal heat. The lava lizards begin their day basking on a warm rock before going out hunting. They spend the heat of the day in a shady spot and become active in the late afternoon when the temperatures begin to cool.
Male Lava Lizards make take up to three mates in their harem. The Lizards are extremely territorial and can be seen on top of rocks doing what looks to be a “push-up” or bobbing their heads up and down. This behavior is to indicate ownership and becomes more prevalent between July and November during mating season.
January 27, 2011 § Leave a comment
The Galapagos Islands are home to a number of endemic wildlife – wildlife found nowhere else in the world. Species include the iconic Galapagos Tortoise and Darwin Finches to Galapagos Mockingbirds and the Galapagos Sea Lion and Flightless Cormorant.
One of the more interesting endemic creatures is the Marine Iguana. These new world lizards are the only sea going iguanas in the world feeding on sea weed and algae. Marine Iguanas can be seen on most islands huddled together in groups for warmth. Their scaling black skin creates a perfect camouflage with the lava rocks along the shore.
They have special glands between their eyes and nostrils that collect and remove salt. The salt gathers in the nostril, and the iguanas sneeze it out periodically spraying the salty water into the air.
Though marine iguanas vary in size and color on each of the islands the most striking are those on Española. Adult male Española Marine Iguanas are brightly colored with a reddish tint except during mating season when their color changes to more of a greenish shade. The best time of year to see these Christmas colored iguanas is between December and February.
August 9, 2010 § 2 Comments
Each summer humpback whales migrate thousands of miles from Antarctica following the Humboldt Current to reach the warm waters of Northern Peru, Ecuador, the Galapagos Islands and even as far north as Costa Rica and Panama. These humpbacks spend the majority of the year in the cooler environment of Antarctica where they feed yet in a yearly even they return to these warmer waters for a few months to mate and give birth.
A full grown humpback may grow to between 40 – 50 feet (16 meters) and can way 40 tons (36,000 kilos). Though both sexes vocalize the male of the species is known for producing the famous whale songs in order to attract a mate. Each song may last between 10 and 30 minutes and a single male is known to sing for periods up to 24 hours.
During the 18th and 19th and early 20th Centuries whales were hunted to a level of near extinction. The Galapagos Islands were a favorite hunting ground of whalers where they would come and kill these graceful swimmers as well as stock up on fresh tortoise meat for their voyage home.
In 1966 the International Whaling Commission banned commercial humpback whaling to prevent the species extinction which at the time was estimated around 5,000. Today some 30,000 – 40,000 whales are thought to exist today globally.
Viewing humpbacks is a spectacular site. Humpbacks are are both active and acrobatic – they are known to breach throwing themselves completely out of the water as well as swim on their backs with their flippers in the air, tail lobbing where they raise their tails out of the water than slap it on the surface and flipper slapping – slapping their flippers on the water surface. Viewing these graceful animals in the wild is an awe inspiring event that everyone should experience at least once in their lifetime.
May 27, 2010 § Leave a comment
by Romero, L. M. and Wikelski, M
Scientists from Germany and the US have gained new insights into the effects of the stress hormone corticosterone on animals. Their study, published in the online issue of the Proceedings of the Royal Society B, shows that the more quickly an animal can shut down the release of corticosterone (which is similar to cortisol in humans), the more likely it is to survive a stressful situation.
The study is extremely timely since it could help predict how wildlife will react to the pollution caused by the massive oil spill in the Gulf of Mexico. ‘As animals encounter the spill, they will have a robust release of corticosterone to help them cope with the consequences of the oil,’ says Dr L. Michael Romero of Tufts University in Medford, US, who is a co-author of the study. ‘However, those animals that can best turn off their corticosterone response once the initial danger from the oil has passed will probably be the most likely to survive.’
Dr Romero and his colleague, Professor Martin Wikelski from the Max Planck Institute for Ornithology in Radolfzell in Germany, base their findings on their study of Galápagos marine iguanas (Amblyrhynchus cristatus).
In 2002, shortly before El Niño struck, the researchers had captured 98 male iguanas and injected some of them with a synthetic hormone that lowers natural corticosterone levels via a negative feedback process.
When the researchers sought out the animals again after the El Niño event, 23 of them had starved to death and 75 had survived. The only difference between the survivors was their ability or inability to turn off the stress response.
The continued stress response triggered elevated levels of corticosterone. As a result, these animals used up all of their protein reserves and grew increasingly weak. Hence, a food shortage impacted them harder than their counterparts that had been able to switch off their stress response.
‘The results from the iguanas indicate that the better an individual is at coping with stress – by turning off the response as soon as possible – the better the chance they have to survive,’ comments Dr Romero.
Marine iguanas are found only on the Galápagos archipelago, where they live on the rocky shores of the islands. The lizards are ideal for this kind of study as their living conditions are rather predictable: They feed exclusively on marine algae growing in the seas surrounding the islands. The risk of starvation due to food shortages regularly caused by El Niño-related global climate events is virtually the only natural threat or source of stress. This makes it possible to exclude other stress factors by and large.
They also have a relatively long lifespan and tend to stay in the same area for most of their life. As a result, they are an excellent model for study in general and determining the ultimate function of a stress hormone response in particular.
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