Bluefin tuna in Greenland waters


This video is called Superfish Bluefin Tuna.

From the Technical University of Denmark:

Bluefin tuna found hunting for mackerel in East Greenland waters

Sep 05, 2014

On a warm summer day in August 2012, Greenlandic fishermen and biologists caught an unusual catch while conducting an exploratory fishery for mackerel.

Three large bluefin tuna, each weighing ca. 100 kg, were among the several tonnes of mackerel that were caught that summer. The presence of bluefin tuna in waters near Greenland is a very rare event, and there are no other scientific reports of its presence so far north as the Denmark Strait. The most recent report of its occurrence near Greenland was a stranding in 1900 in the southwesternmost tip of Greenland at Qaqortoq (formerly known as Julianehåb).

Bluefin tuna usually search for prey in areas where surface temperatures are warmer than 11 C. However, because temperatures in August 2012 in the Denmark Strait were so warm, and because one of its favorite prey species, mackerel, had already expanded its range into the region, it is likely that bluefin tuna has expanded or is presently expanding its habitat to more northerly regions,” explains professor Brian MacKenzie, who together with senior scientist Mark Payne, senior scientist Jesper Boje (both from DTU Aqua), senior scientist Jacob Højer (Danish Meteorological Institute) and Department Head Helle Siegstad (Greenland Nature Institute, GNI), has been investigating the reasons why bluefin tuna and its summer dining menu are on the way to more northerly regions than usual.

The investigation, which was conducted as part of the EU projects Euro-Basin and NACLIM at the Centers for Ocean Life and Macroecology, Evolution and Climate, has been published in the August 2014 issue of the peer-reviewed scientific journal Global Change Biology.

Disappearance from Danish waters

The reason why Brian MacKenzie and his colleagues initially became interested in these tuna bycatches was to document changes in its migration behaviour and distributional range, and how these are being influenced by climate change and the abundances of both bluefin tuna themselves and their prey.

“The scientific community does not have a solid understanding of the factors that affect the migrations and geographical distribution of bluefin tuna and many other migratory species, but new knowledge like this can potentially help explain the unsolved mystery of why bluefin tuna disappeared from waters near Denmark and in the Norwegian Sea during the 1960s, and especially when they might come back,” says Brian MacKenzie, noting that in addition to the appearance in Denmark Strait in 2012, Iceland and Norway have been allocated new fishing quotas (30 tonnes each) for the species in 2014.

“The new quota allocations are presumably because the species has begun to expand its northerly feeding areas farther north. If summer temperatures continue to increase during this century, and if both bluefin tuna and its prey species are managed in sustainable ways, then it is likely that bluefin tuna could become a regular summer visitor in east Greenland waters, at least as far north as the Denmark Strait,” states Brian MacKenzie.

One, two or many tuna

The Denmark Strait is normally a much colder area without warm-adapted species such as bluefin tuna. How many tuna were present in summer 2012 is unknown.

“The data we have available are too limited to estimate how many tuna came so far north, but because the species is a schooling species, with schools having ca. 10-100 individuals, and because the fishermen caught the three tuna in the same haul, it is likely there were many more present,” Brian MacKenzie said.

“We are planning further investigations to determine whether this new migration behaviour toward more northern waters could be the result of an increase in the total population of Bluefin tuna,” the DTU Aqua-professor stress.

“Regardless of whether the stock has increased or not, climate-related changes in distributions of commercial fish like these we have seen already for mackerel and herring will mean that international management authorities will need to develop new fishery and ecosystem management plans,” says co-author Helle Siegstad, Head of the Department for Fish and Shellfish, GNI.

“We have already seen during the past few years with the case of the expansion of mackerel and herring into waters near the Faroe Islands, Iceland, Norway and now Greenland how complicated the discussions between jurisdictions can become. It will be important in future that we can provide authorities with a solid scientific and data basis, on for example bluefin tuna, when they are making new fishery management decisions,” says Brian MacKenzie.

The study, which details in depth the data as well as discusses key questions relating to the migratory origins of the tuna caught in Greenland, will form part of a theme session topic at the ICES Annual Science Conference which kicks off on 15 September in the Spanish coastal city of A Coruña.

Cambrian prehistoric predator evolution, new research


This video says about itself:

26 March 2014

T[amisiocaris]. borealis, an ancient predator, probably used its spiny appendages to sweep through the water for prey and then bring it into its mouth, as these animations show. Credit: Martin Stein. Read more here.

From Wildlife Extra:

Large ocean predators evolved into gentle giants 520 million years ago

April 2014: Large marine creatures that roamed the Earth’s oceans more than 520 million years ago have been found to filter food from the water in a similar way to today’s blue whales and evolved into a gentle sea giant from a large marine predator that feasted on large prey, say scientists.

Newly discovered fossils from North Greenland showed that these ancient giant marine animals used bizarre facial appendages to trawl for nekton and plankton from the seas.

The North Greenland fossil, called Tamisiocaris, was a member of the iconic anomalocarids group of early marine animals which roamed the Cambrian and later Ordovician oceans. They swam using a set of flaps down either side of the body and probably captured large prey with specialised grasping appendages in the front of the mouth.

The team demonstrates that the Tamisiocaris had evolved into a suspension feeder by modifying its grasping appendages into a filtering apparatus that could be swept like a net through the water trapping small crustaceans and other organisms as tiny as half a millimetre in size.

The research, funded by the Agouron Institute, Carlsberg Foundation and Geocenter Denmark, was led by the University of Bristol and also included researchers at Durham University, the University of Bath and the University of Copenhagen.

As well as shedding light on the evolution of the Tamisiocaris, the researchers said their discovery also showed how productive the Cambrian period was and how vastly different species of anomalocarids evolved at that time. It also provides further clues into the ecosystems that existed hundreds of millions of years ago, they said.

Study lead author Dr Jakob Vinther, a lecturer in macroevolution at the University of Bristol, said: “The fact that large, free-swimming suspension feeders roamed the oceans tells us a lot about the ecosystem.

“Feeding on the smallest particles by filtering them out of the water while actively swimming around requires a lot of energy – and therefore lots of food.”

In order to fully understand how an anomalocarid could have fed, Dr Martin Stein from the University of Copenhagen, Denmark, created a 3D computer animation of the feeding appendage to explore the range of movements it could have made.

Dr Stein said: “Tamisiocaris would have been a sweep net feeder, collecting particles in the fine mesh formed when it curled its appendage up against its mouth.

“This is a rare instance when you can actually say something concrete about the feeding ecology of these types of ancient creatures with some confidence.”

The research about this was published here.

April 2014: An international team of researchers from the US, China and the UK have discovered the earliest known cardiovascular system in fossilised remains of an extinct marine shrimp that lived over 520 million years ago. The finding sheds new light on the evolution of the body in the animal kingdom and shows that even the earliest creatures had internal systems that strongly resemble those found in their modern descendants: here.

Enhanced by Zemanta

Greenland ‘Grand Canyon’ discovery under ice


This video from the USA is called Greenland Rocks, for Geologists.

From Reuters:

Giant Canyon Found Entombed under Greenland Ice

A vast and previously unmapped gorge 800 meters (half a mile) deep has been found under ice in Greenland, comparable in size to parts of the Grand Canyon in the United States, scientists said.

By Environment Correspondent Alister Doyle

OSLO – A vast and previously unmapped gorge 800 meters (half a mile) deep has been found under ice in Greenland, comparable in size to parts of the Grand Canyon in the United States, scientists said.

Other studies have also revealed a rift valley entombed in Antarctica‘s ice in 2012 that scientists said may be speeding the flow of ice towards the sea, and a jagged “ghost range” of mountains buried in Antarctica in 2009 similar to the Alps.

“It’s remarkable to find something like this when many people believe the surface of the Earth is so well mapped,” lead author Jonathan Bamber, of the University of Bristol in England, said of the canyon described in Friday’s edition of the journal Science.

“On land, Google Street View has photographed just about every building in every major city,” he told Reuters of the study, using ice-penetrating radar and carried out with colleagues in Canada and Italy.

The canyon is 750 km (470 miles) long in central and north Greenland and comparable in scale to parts of the Grand Canyon that is twice as deep – 1.6 km – at its deepest, they wrote. The Greenland canyon is buried under about 2 km of ice.

About as long as the Rhone river in France and Switzerland, the ravine was probably cut by an ancient river that eroded rocks as it flowed north before temperatures cooled and ice blanketed Greenland 3.5 million years ago, they wrote.

The gorge probably still plays a role in draining some meltwater from beneath the ice sheet.

ICE FLOWS

The scientists used airborne data collected mainly by NASA and by scientists in Britain and Germany to piece together maps of the canyon. At some frequencies, ice is transparent to radio waves that bounce off the bedrock.

Bamber said the gorge would help scientists refine models of how Greenland’s ice sheet slowly flows downhill but was unlikely to affect understanding of how global warming is melting ice.

“I don’t think it’s particularly influential” in determining the rate of ice flow, echoed David Vaughan of the British Antarctic Survey. He said the canyon was so deep under the ice that it was unlikely to be affected by any warming trend for many decades.

Vaughan led a four-year international study called ice2sea, which said in May that world sea levels could rise by between 16.5 and 69 cm (6-27 inches) with moderate global warming by 2100, partly because of a thaw of Greenland and Antarctica.

He told Reuters a few blanks remain on the map, including two areas of east Antarctica that scientists jokingly dub the “Poles of Ignorance”.

(Reporting by Alister Doyle; Editing by Alistair Lyon)

Northern light video


, who made this video, writes:

More details about the “making of” on newswatch.nationalgeographic.com/2013/06/18/how-a-stunning-aurora-video-was-made/.

The soft light of the arctic regions attracted me magically so that I decided to dedicate a project to it. Around the polar circle light occupies a very important role, especially in winter. During the freezing months the sun creeps only along the horizon providing thus long hours of this tender twilight that occurs before sunrise and after sunset. But the nights are even longer and then another special light brights up the sky: the aurora borealis. In this film I wanted to show how individual the northern lights are: they may dance very fast in a frenetic rhythm or explode in a red-purple firework or they may just glow greenish over the starry sky vaguely distinguishable by the human eye. Every night there is a different night show – if the polar lights appear as they use to be very shy divas.

As a non resident of the Arctic regions it was very difficult for me to hunt the northern lights. I travelled different times to the distant regions at the polar circle. It was not easy enduring the freezing temperatures and the darkness and sleeping in the tent or in the car when the harsh wind was shaking it too strong. But after a year I had the incredible luck to gather enough video material for this film project. Especially on my last trip to Tromsö in february 2013 I experienced incredible beautiful aurora borealis.

The footage was captured in Greenland, Norway (on the Lofoten islands and in the Troms region), Iceland and Finland.

The surreal atmosphere of the landscapes is emphasized thanks to the wonderful music of the talented and creative composer Pablo Garmón vimeo.com/pablojgarmon.

Visitors from Greenland and Togo, welcome!


About three months ago, I wrote a blog post about from which countries visitors had come to my blog, and about which countries were unrepresented so far.

Among those countries with no visits then were Togo in Africa; and Greenland.

This video is called Wild Greenland – home of musk oxen and arctic char.

This morning, WordPress stats say that the first ever visitor from Greenland has arrived. Yeseque, welcome!

This video is called Discover Togo.

Also, there have been two visits from Togo. Not today; I am not sure when. Bienvenu, welcome!