Sealion

It seems that sea lions have once again pulled the wool over the eyes of researchers. We all know it’s a rough world, and no less is true of those poor orphaned sea lion pups. However, decades of painstaking research has proven that the sea lion females shun any sea lion pups which aren’t there own.. Or do they?

A new bit of genetic research of the populations of Californian sea lions, published this past Monday in the online journal PloS ONE, now sheds some new light on the subject, and states that sea lions are not as cold as they are made out to be.

Up to seventeen percent of the females in the California sea lions populations off of Mexico’s coast will actually take on an orphaned pup as one of their own offspring, according to the new research. What is even more amazing, is that the researchers were able to watch the females care for these pups year after year.
“Females are incredibly aggressive toward pups that aren’t theirs. They’ll bare teeth and bark, sometimes grab and toss pups that aren’t their own away,” explains a marine biologist at Arizona State University who made the discovery through an unrelated research effort, Ramona Flatz. “That they adopt at all really surprised us. We didn’t think it happened.”

So, while the chances are not that high that an orphaned pup can find an adoptive mother, the chance still exists, so like people, there are some decent sea lions out there…

Tiger shark - Credit: Richard Ling

The people in attendance mowed down on cheese and crackers, celery and crisps. But as soon as Greg Skomal, a state shark expert, opened up his mouth, he told them what it really meant to chow down.

Skomal, who was the guest of honor at the Harwich Conservation Trust’s yearly get together this past Sunday evening, gave the people in attendance at Wequassett Resort the low down on great white sharks. He told of tagging them off Chatham’s coast near Monomoy. He explained how they weren’t very discriminant about what they chowed down on, and how they hunt a myriad of fish. Given that there is an abundant supply of gray seals in the area, and it’s ever increasing, more and more great white sharks are going to be making their way to the waters of the Cape every summer.

“You can eat as much popcorn you want or you can have one big steak,” Skomal commented, which accurately depicts why great white sharks like to pick out the gray seals in the area, especially near Monomoy. Just one gray seal can satisfy a great white shark for one to two months.

According to Skomal, who happens to be a shark expert with the state Division of Marine Fisheries, has commented no one can know for sure just how many great white sharks make an appearance every year, but it is becoming quite a “hot spot” off the Cape.

A team of U.S. scientists has documented the first transmission of the lethal phocine distemper virus from the Atlantic Ocean to a population of sea otters living along the coast of Alaska.

The presence of phocine distemper virus has been confirmed in nasal swabs take from live otters and through necropsies conducted on dead otters found along the Alaskan coast. The findings also indicate that the virus was passed between seal species across Northern Canada or Arctic Eurasia before reaching the otters in Alaska’s Kachemak Bay.

Prior to this study, PDV had never been identified as the cause of illness or death in the North Pacific Ocean and researchers suggest that diminishing Arctic sea ice may have opened a new migration route for both animals and pathogens.

The study was carried out by researchers from two California universities and the Alaskan branch of the U.S. Fish and Wildlife Service. It has been published in ”Emerging Infectious Diseases”, a journal published by the U.S. Centers for Disease Control and Prevention.

What is phocine distemper virus (PDV)?

Phocine distemper virus (PDV) is a paramyxovirus of the genus Morbillivirus. It is dangerous for pinniped species, especially seals, and is a close relative of the canine distemper virus (CDV).

PDV was first identified in 1988 when it caused the death of approximately 18,000 harbour seals, Phoca vitulina, and 300 grey seals, Halichoerus grypus, in northern Europe. In 2002, the North Sea lost approximately 21,700 harbour seals in new a PDV outbreak – estimated to be over 50% of the total population.

Infected seals normally develop a fever, laboured breathing and nervous symptoms.

The first confirmed sighting of a leucistic Southern elephant seal has occurred on a beach on Marion Island, fairly near Antarctica. The entire seal is creamy white, except for eyes and nose which sports the brown colour normally seen in elephant seals.

“It’s quite something in a species which is well-known,” says Ryan Reisinger of the University of Pretoria in South Africa, one of the researchers who discovered the seal.

There have been a few rare previous records of lighter coloured elephant seals, but none of these animals have been confirmed as leucistic. Reisinger and his colleagues have been researching Marion Island elephant seals for several years without ever encountering a leucistic specimen before.

See a picture of the seal here.

As reported earlier , the European Union has decided to ban the import of seal skin and other seal products hailing from commercial seal hunting.

This has upset Canadian seal hunters since Italy and Denmark, both members of the European Union, are two major importers of seal products. Italy imports most of their seal skins from Russia, but Denmark has always been an important trade partner for North American seal hunters, partly due to Denmark’s traditional connection to Greenland.

According to a statement from Canadian Trade Minister Stockwell Day, the federal government is now getting ready to move in with an appeal against the ban, which they see as a clear breach of WTO regulation.

“We’ll go to the WTO because it’s clear in WTO regulations that if one country wants to ban the products of another, it has to have clear scientific, medically acceptable reasons for doing so, and this EU ban is not based on hard science,” Day said.

The Canadin government believes that Canada deserves an exemption from the import ban since it follows internationally accepted guidelines regarding seal hunting, e.g. by prohibiting the clubbing of baby seals while they still have their white coats.

Day claims that the European ban is based on “people’s feelings” rather than hard facts, and says that the trade action will proceed unless the European Union Parliament exempts Canada and other countries that he said practise humane and sustainable seal hunting. According to Day, seal hunt proponents erroneously portray seal hunting as it was 40 years ago.

The suggested seal import ban must still be approved by individual European governments before becoming law but can, if passed, come into effect as early as next year. If the is approved, it will cause an annual 2 million USD loss for the Canadian industry.

Canadian Fisheries Minister Gail Shea agrees supports the government’s planned trade action.

“When you live in small coastal communities, sometimes there’s not many opportunities to make some additional money,” she said. “We have a number of families who make up to 35% of their annual income from the seal hunt. So yes, I do think it’s very important.”

As reported earlier, the proposed European seal import ban will contain some exemptions and seal products resulting from hunts traditionally conducted by Inuit and other indigenous communities can still be imported to and marketed in European Union countries even if the ban is approved. Products that result from hunting conducted for the purpose of sustainable management of marine resources on a non-profit basis will also be allowed, and individual travellers will be permitted to bring seal products to the European Union as long as the import is of an occasional nature and consists exclusively of goods for the personal use of the traveller.

Modern seals, walruses, and sea lions are all descendants of animals that once lived on land but eventually swapped their terrestrial lifestyle for a life in the ocean. Until now, the morphological evidence for this transition from land to water has been weak, but researchers from Canada and the United States have now found a remarkably well preserved skeleton of a newly discovered carnivorous animal: Puijila darwini.

Skeletal illustration of Puijila darwini.
Credit: Mark A. Klingler/Carnegie Museum of Natural History

Seals, walruses and sea lions all have flippers; a type of limb perfectly adapted for swimming and moving around in water. But how could a land living animal develop flippers? The adaptation evolved gradually over a long period of time, as some land living animals adapted semi-aquatic habits. New research now suggests that the genus Puijila is the “missing” evolutionary link between our modern seals, walruses and sea lions and their terrestrial ancestors.

Puijila darwini is described as having fore-limbs comparatively proportionate to modern carnivorous land animals rather than to pinnepeds*, a long tail, and webbed feet.

“The remarkably preserved skeleton of Puijila had heavy limbs, indicative of well developed muscles, and flattened phalanges which suggests that the feet were webbed, but not flippers. This animal was likely adept at both swimming and walking on land. For swimming it paddled with both front and hind limbs. Puijila is the evolutionary evidence we have been lacking for so long,” says Mary Dawson, curator emeritus of Carnegie Museum of Natural History.

The Puijila darwini skeleton was found in Nunavut, Canada in the remains of what was once a crater lake on coastal Devon Island. The first pieces of the skeleton were found in 2007, but the important basicranium wasn’t found until researchers paid a new visit to the site in 2008. Without a basicranium it is much more difficult to determine taxonomic relationships.

Based on Paleobotanic fossils, Devon Island had a cool, coastal temperate climate during the Miocene when Puijila darwini roamed the seashore. The conditions were quite similar to modern-day New Jersey and the lakes would freeze during the winter, something which probably prompted Puijila darwini to move over land from the lake to the sea in search of food.

“The find suggests that pinnipeds went through a freshwater phase in their evolution. It also provides us with a glimpse of what pinnipeds looked like before they had flippers,” says Natalia Rybczynski, leader of the field expedition.

The idea that semi-aquatic mammals may have undergone a transition from freshwater to saltwater is not new. In the On the Origin of Species by the Means of Natural Selection, Charles Darwin writes “A strictly terrestrial animal, by occasionally hunting for food in shallow water, then in streams or lakes, might at last be converted in an animal so thoroughly aquatic as to brace the open ocean.”

The oldest well-preserved pinniped animal belongs to the genus Enaliarctos and was a sea living creature with flippers. This species has been found on North Americas northern Pacific shores which have lead researchers to believe that the evolution of pinniped animals may have taken place mainly around the Arctic. This new finding of Puijila darwini strengthens that notion.

You can find more information about Puijila darwini and the origin of pinnipeds in the April 23 issue of the journal Nature.

http://www.nature.com

http://www.nature.com/nature/index.html

* The pinnipeds are a widely distributed and diverse group of semi-aquatic marine mammals. It contains the families Odobenidae (walruses), Otariidae (eared seals, including sea lions and fur seals), and Phocidae (earless seals). The name is derived from the Latin words pinna, which means wing or fin, and ped, which means foot. The pinnipeds are therefore also known as fin-footed mammals.

Tagged Seals are helping Australian scientists learn a great deal more about places, in the deep oceans of Antarctica, where they themselves can not travel. This summer 7 female Weddell Seals were tagged to help researchers gather information on the changes global warming is having on the oceans. The Weddell Seal is a constant inhabitant of the Antarctic, and they are now being used by an international program monitoring deep diving mammals on both the North and South Pole.

The Seals are fitted with a satellite  transmitter that relays data daily back to the researchers.  The data provides depths of the seals dives, the time they spend under water, and where they are going to eat. But, more importantly, the transmitter also relays vital information about the surrounding oceans; such as water temperatures and salinity of the oceans. So far the salinity of the oceans in the arctic have begun to decline, leaving scientists guessing that melting ice due to global warming is to blame.

However, research is done only in winter, and come spring, the seals molt and the tracking devices fall off. Scientist are planning on several more years of this fascinating seal tagging to help better understand the oceans around us.

You can read the entire article on the Weddell Seal Tagging studies here: http://www.abc.net.au/news/stories/2008/04/29/2229776.htm

picture provided by Creative Commons at:  http://creativecommons.org/licenses/by/2.5/

 (disclaimer: Creative Commons has no affiliation to the AC or the views or thoughts published in this article.)

According to an article published by The Guardian, scientists believe that krill have declined 80 per cent since the 1970s. Why this has happened remains unknown, but it might be due to global warming. According to estimates made by the British Antarctic Survey (BAS), there is roughly 100 million tonnes krill left, while krill harvesting companies place the figure at 400-500 million tonnes. The Convention on the Conservation of Antarctic Marine Living Resources allows 4 million tonnes of krill to be caught in the Southern Ocean per year. Until now, this number has seldom been reached; in a normal year, less than 20 percent of the permitted 4 million tonnes have been caught.

Today, the emerging interest in health products such as Omega 3 oil and Omega 3 fortified food is causing a boom in krill fishing. A majority of the fished krilled is used to produce Omega 3 oil and other health supplements, or as fish-farm feed. So called “suction harvesting” is now used to meet the demand for krill.

So, why care about a tiny crustacean? The truth is that entire ecosystems depend on krill and krill are also able to help us remove carbon dioxide from the atmosphere. Some species, such as the gigantic Blue Whale, feeds directly on krill. Other species, such as penguins and seals, are indirectly depending on krill since they feed on animals that feed on animals that eat krill.

If you want to learn more about krill and hear different experts explain their view on the current situation, read the full article at The Guardian: http://www.guardian.co.uk/environment/2008/mar/23/fishing.food