Hagfish

Hagfish, an elongated scavenger found on the bottom of the sea, is truly a weird and wonderful creature. A single fossil of hagfish shows that is has undergone little evolutionary change in the last 300 million years, and the hagfish is believed to the be oldest living connection to the first vertebrate. Its the Hagfish, an elongated scavenger found on the bottom of the sea, is truly a weird and wonderful creature. A single fossil of hagfish shows that is has undergone little evolutionary change in the last 300 million years, and the hagfish is believed to the be oldest living connection to the first vertebrate. Its eyespots can detect light but lacks both lens and extrinsic musculature, and is therefore believed to show a significant step in the evolution of more complex eyes. The hagfish is also famous for exuding vast amounts of a gel-like slime when threatened. An adult hagfish can secrete enough slime to turn a 20 litre (5 gallon) bucket of water into slime in a matter of minutes. When captured, e.g. by a human or predatory fish, it will tie itself in an overhand knot which gradually works its way from the head to the tail of the hagfish, scraping off the slime as it goes, thus freeing the hagfish from its captor and from the slime in one swift movement.

Hagfish eat dead and injured sea creatures and will borrow into the body cavity of a dead (or dying!) animal to devour it from within. Once its full, it can go several months without feeding again.

Now, a new study on hagfish caught near Vancouver Island in Canada has unveiled yet another remarkable fact about the hagfish – it seems as though this fish is actually able to eat with its skin and gills, i.e. absorb nutrients through its skin and gills instead of using its mouth.

A research team* headed by Chris Glover of the University of Canterbury in New Zealand and Bamfield Marine Sciences Center took skin and gill tissue from hagfish and tested the tissues’ absorption of two different amino acids.

“We wanted to start with a simple dissolved organic nutrient, and given the fact that the food source is a large decaying pile of protein, an amino acid seemed to be the best place to start,” says Glover.

When a hagfish has managed to burrow its way into a carcass, it will feed surrounded by a high concentration of dissolved nutrients, so being able to absorb food through more than just its mouth could come in handy.

The results of the study carried out by Glover and his colleges indicate that specific molecular mechanisms exist within the hagfish tissues to move the two tested amino acids into the body of the fish. When researchers increased the concentration of amino acids the tissue increased its absorption – but only up to a certain level.

“A quick and simple calculation suggests that the skin in particular may be capable of absorbing nutrients at levels equivalent to that of the digestive tract!”, says Glover.

There are quite a few invertebrates, including many mollusks and worms, that can absorb nutrients through their skin. But up until now, no vertebrates have been known to have this capacity. The hagfish may represent a transition between the feeding habits of aquatic invertebrates like mollusks and the more specialized digestive systems found in vertebrates. While some organisms exchange nutrients with the water around them in order to maintain their body fluid salt concentrations, the hagfish is – according to Glover – likely to transport amino acid molecules through its skin and gills exclusively to feed itself.

The paper “Adaptations to in situ feeding: novel nutrient acquisition pathways in an ancient vertebrate” has been published in the most recent issue of journal Proceedings of the Royal Society B: Biological Sciences.

* Chris N. Glover (http://www.biol.canterbury.ac.nz/people/glover.shtml) School of Biological Sciences, University of Canterbury, Christchurch, New Zealand Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada

Carol Bucking (no bio page available) Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada Department of Zoology, University of British Columbia, British Columbia, Canada

Chris M. Wood (http://www.biology.mcmaster.ca/faculty/wood/wood.htm) Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada Department of Biology, McMaster University, Ontario, Canada

Hammerhead shark by Suneko

Shark Advocates International is giving a warm welcome to progress towards helping conserve sharks. This progress was made at the annual meeting of the International Commission for the Conservation of Atlantic Tunas (ICCAT) this week.

There were a record number – six to be exact – proposals for shark measures, the parties of the ICCAT agreed to put a stop to the retention of oceanic whitetip sharks, prohibit exploiting of hammerheads, and set up a process for punishing countries who do not get with the program and accurately report catches and reduce fishing pressure on shortfin mako sharks. The proposals to stop the retention of abundant thresher and porbeagle sharks were thrown out as a measure to help ICCAT gain a stronger position to ban shark “finning” by prohibiting removing the fins of a shark at sea.

“ICCAT has taken significant steps toward safeguarding sharks this week, but much more must be done to effectively conserve this highly vulnerable species,” explained President of Shark Advocates International, Sonja Fordham, who serves on the US ICCAT Advisory Committee and has participated in ICCAT meetings since 2004. “We are particularly pleased with the agreements aimed at protecting oceanic whitetip sharks and reducing international trade in the fins of hammerhead sharks, as well as US efforts to conserve mako sharks.”

It’s good to see that progress is being made, and all parties involved are rather pleased that the meetings have gone so well so far. Hopefully, this means a better world for sharks.

The very first research study to take a gander into what kind of biological activity there is in the deepest part of the ocean crust has turned up bacteria with an astonishing range of abilities, which include eating oil, natural gas, and “fixing” or storing carbon.

This new study, which was recently released in the journal PloS One, has demonstrated that a vast number of bacterial lifeforms were thriving, even when the temperatures reached the boiling point of water.

“This is a new ecosystem that almost no one has ever explored,” commented a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University, Martin Fisk. “We expected some bacterial forms, but the long list of biological functions that are taking place so deep beneath the Earth is surprising.”

The Oceans crust cover close to seventy percent of the surface of our planet and it’s geology has been explored to a certain degree, however no one has bothered to look into its biology – because it is hard to do, and very costly, but also because most scientists have always taken it for granted that nothing was happening down there.

The temperatures rise exponentially as you get deeper – as any high school graduate can tell you – and researchers now think that the maximum temperatures which can harbor life are at about 250 degrees.

So, now you know, when we think we know something about the world – such as boiling water kills bacteria – we are thrown a curve ball. However, the discovery that some of these organisms like to eat oil is very exciting indeed.

White Shark - Terry Gross

A simple wrong turn, no doubt by one or two pregnant females, somewhere in the vicinity of 450,000 years ago during climate changes, could have caused sharks to show up in a place they were no supposed to be. This is according to research which was Published this past Wednesday, in Proceedings of the Royal Society B. (It should however be noted that we don´t necessarily agree with the findings here at AC as competition for space is an easier explanation on why some fish first swam into the Mediterraneanan.)

And of course liking the area, they have stayed on in the Mediterranean – albeit in small groups – because much like salmon they go back to where they were born. It is also believed that the narrow channels in the Mediterranean have made it nigh impossible for the sharks to get back out again.

Researchers believe this “wrong turn” happened due to a mixture of climate change, high sea levels, and changing currents at the time, and as a result the sharks gained a permanent foothold in the Mediterranean.

Thanks to genetic analysis and tagging, researchers now know that sharks do indeed swim between Australia and Africa, and actually have a tendency to swim towards the east to where they were born, making their way using cues from the ocean currents they swim through.

However, in the case of long long ago, scientists still believe that some sharks simply became confused, and wound up a little bit off course, and as a result, permanently made a change in the way the world we live in today is.

Spanish Fishing boat

The most widely accepted method of being able to determine the health of the world’s oceans and fisheries led to inaccurate conclusions in almost fifty percent of the ecosystems where it was utlilized.

This new analysis was done by an international group of fisheries researchers, and has been published in this week’s issue of the journal Nature.

“Applied to individual ecosystems it’s like flipping a coin; half the time you get the right answer and half the time you get the wrong answer,” explained a University of Washington aquatic and fisheries researcher, Trevor Branch.

“Monitoring all the fish in the sea would be an enormous, and impossible, task,” explains a program director in the National Science Foundation’s Division of Environmental Biology, Henry Gholz, whose department helped to fund the research with NSF’s Division of Ocean Sciences.

“This study makes clear that the most common indicator, average catch trophic level, is a woefully inadequate measure of the status of marine fisheries.”

Back in 1998, the journal Science released a groundbreaking report that was the first to utilize trends in the trophic levels of fish which were reeled in to help figure out the health of world fisheries.

The trophic level of an organism indicates where it falls in the different food chains, with microscopic algae at a trophic level of one and large predatory creatures – such as sharks, halibut and tuna – at a trophic level of about four.

This 1998 report relied on forty years of catch data, and took the average of the trophic levels of those specimens which were caught.

Chagos Islands

Well, it’s nice to see there is still some decency in the world today. A Billionaire from Switzerland has used some of their vast resources to help save plans to create the largest marine reserve in the world, and alleviate the pressures placed upon it from public spending cuts.

Government officials are currently engaged in talks over a 3.5 million GBP deal for Ernesto Bertarelli, America’s Cup-winning yachtsman, to help fund the efforts to police the zone around the Chagos Islands.

The area which is due to be protected, dubbed the MPA, is going to cover quite a bit of area. The proposal is to cover somewhere around 250,000 square miles of sea around the archipelago in the Indian Ocean and include a “not take” reserve which is going to ban commercial fishing.

The plan was approved last April by David Miliband, then foreign secretary, even though there were complaints that the government was not taking the territory’s exiled population into consideration.

You see, the Chagos have been in the midst of a heated debate for a long time now, due to the fact that the islanders were exiled to make way for the Diego Garcia US airbase, and are continuing legal proceedings to return to their homes.

There are still other concerns that the project may fail due to the lack of private funding to offset the amount they would lose from tuna fishing licenses.

So, hats off to the billionaire for trying, and hopefully it will be pushed through. It isn’t often a billionaire steps aside and tries to do something good in the world.

Thermal Vent

Well, just when you are comfortable knowing that what you know is accurate, the world comes along and throws you another curve ball. We used to know there were 9 planets, now there are 8, we used to know the earth was the center of the solar system, now we know better.. Now, just when you thought you pretty much knew your basic zoology, an amazing new discovery has been made that is basically going to force some poor guy to rewrite the molluscan, larval ecology and invertebrate text books.

Between the 1850’s and the 1870’s supposedly all known forms of snail were discovered. However, thanks to modern technology, and some persistent researchers, we now know that we were mistaken, and that the forms of snail are really much more diverse than originally thought.

This new snail larval form is really turning heads, and here’s why. This larval form discovered is the first of its kind to be found to be a free-swimming pre-veliger larva. This is rather interesting because normally they don’t swim freely. Not only that but it appears these new little guys can actually turn hydrogen sulfide, and methane as an energy source.. Imagine, a snail which subsists on farts…

Credited with this astounding discovery are Anders Waren, a Swedish Naturalist from the Royal Museum of Natural History in Stockholm, and collegue Philippe Bouchet.

They have been working on this project since the 1980s, and have finally made their marks on history. These are a pair to watch folks, who knows what they might discover next?

Many people are happy, and patting themselves on the back after finding the first baby sea horse at one of the leading breeding colonies in Dorset.

The tiny fry, what you call a tiny baby seahorse, discovered at Studland Bay is 4 centimeters in length.

Displayed sea horse is not from the dorset population.

The Seahorse Trust has claimed that the seahorses are an endangered animal, as many boats and mooring chains are taking big hunks and tearing up the seabed.

The Marine Management Organization, a government entity, has said that although research has been ongoing into the subject, there was no conclusive evidence that mooring chains are a threat to seahorses.

The Seahorse Trust is pushing for the protection of these amazing animals under the Wildlife and Countryside Act, which came into existence in 2008.

“The trust and its volunteer divers have seen adults, pregnant males and juveniles on the site before but never a baby (fry),” a representative of the Seahorse Trust has commented.
“It does not mean they are thriving, quite the reverse, they appear to be hanging on in there against the odds of hundreds of boats dropping anchors and mooring chains ripping up the seabed, destroying their fragile home.”

The main goal of the Seahorse Trust is to get those nasty moorings replaced with more environmentally sound ones which do not damage seagrass, and for boat users to switch to these new devices.

Hopefully the discovery of this new baby seahorse will prompt some more interest in the issue, and something will be done to help protect these magnificent sea creatures.

Old drawing of dragonfish

The conundrum of why a particular group of deep sea fish have a gap between their skull and spinal columns has finally been solved by a crack team of researchers, which include representatives from the Natural History Museum.

It appears that the Barbeled Dragonfish also have a number of bones missing which would normally connect their skulls to their spine, and this has been puzzling researcher for quite some time.

There are a total of 28 genera of these fish, which represent over 270 species, and all of them have this same gap. However, are these missing bones always the cause?

An international group of scientists including Dr. Nalani Schnell, of the University of Tubingen; Dr Ralf Britz, of the Natural History Museum; and Dr. David Johnson, of the smithsonian Institution in Washington DC.

Together they performed the most in depth and comprehensive study for this group.

They stained the fish so that their bones and nerves would show up in different colors, so they could discern them properly.

The researchers discovered that the bones were one missing in 2 of the different genera of barbeled dragonshish, Chauliodus, and Eustomias and in the Leptostomias gladiator as well. The loss of these bones occurred naturally as they evolved.
Dr Britz explains, ‘In stomiids [barbeled dragonfishes are in the Family Stomiidae], vertebrae develop in an unusual fashion from back to front, which facilitated the loss of front vertebrae. They have failed to form in development leaving a gap between the skull and backbone.

However, the gap in the spine of the other barbeled dragonfish is caused by a lengthening of the notochord.

There you have it… Mystery solved.

Sea otter. Credit: Mike Baird

After 10 years of a steady recovery, the southern sea otter – a species on the federal list as being threatened – populations are declining for the second year running, so says a population survey conducted by researchers with the U.S. Geological Survey.

“We have seen a decrease in sea otter numbers throughout most of their range, particularly in those areas where most of their reproduction occurs, while pup counts have dropped to 2003 levels,” explains the head researcher for the yearly survey, Tim Tinker of the USGS Western Ecological Research Center. “A number of human and natural factors may be influencing this trend, and we are working to better understand what those are.”

The estimates of the population are calculated as three year averages of the yearly results of the surveys, which make allowances for variables which arise during different times of observation and give researchers a better picture of the trends in abundance. The estimate this year – averaging out the results from surveys from 2008, 2009 and 2010 – is a mere 2,711 otters. This signifies a 3.6 percent drop in the population overall, and an 11 percent drop in the number of otter offspring, compared to the estimates of 2009.

“Remember, sea otter health can tell us a lot about the health of the coastal waters that humans also enjoy,” Tinker reiterates. “So, we’re eager to learn more.”

Well, if that’s an indication.. Our world might just be in a heap of trouble.. Let’s hope they get to the bottom of it quickly.