Friday, May 30, 2008

A Wolf at the Door

With their portly blue heads and gaping toothy maw, it has been said that only a wolf fish could love another wolf fish. Their peculiar skin lacks scales, and casts a green, blue, or even purplish hue (though this flamboyant colouring quickly fades when brought to the surface). However, it has also been said that the best habitat for a wolf is in the human heart, and you can see that this adorable crocheted version was crafted with love.

Three species of wolf fish occur in Atlantic Canadian waters: northern wolf fish (Anarhichas denticulatus), spotted wolf fish (Anarhichas minor), and Atlantic wolf fish (Anarhichas lupus). Lone wolves of the sea, these fish enjoy a mostly solitary life, making their homes in deep rocky outcroppings, where they chow down on mollusks, crustaceans, echinoderms, and other crunchy sea floor fauna with their powerful canine-like teeth.

While wolf fish are not targeted by fishermen, all three species experienced serious population declines during the 1980s and 1990s. Bottom trawls damage spawning habitat by disturbing the rocky structure they use for shelter and nesting, and they are often caught as by-catch. Canada's Species at Risk Act (SARA) lists the northern and spotted wolf fish as threatened and the Atlantic or striped wolf fish as special concern. SARA makes it illegal to harm these vulnerable creatures, but for now, a special DFO "allowable harm assessment" allows fishermen to land and sell some wolf fish.

Most wolf fish on the market is landed incidentally by otter trawls targeting haddock or greenland halibut. It is popular in UK fish and chip shops where it is often sold as Scotch halibut, lobo or woof. Here in Atlantic Canada, it more likely to be marketed as leopardfish, Atlantic catfish, or simply, catfish. Unfortunately, lax labeling laws in Canada currently make it difficult for consumers to make sustainable seafood choices. If you see catfish on offer at your local fish counter, make sure to ask for the species name along with how and where it was caught... or you might end up eating an endangered species for supper.

Tuesday, May 27, 2008

Friendly hermits

Hermit crabs belong to a large family of decapod crustaceans who move into empty snail, periwinkle, or other mollusk shells to protect their vulnerable rear ends. Scientists have counted over 800 species, found everywhere from the deep sea to tropical tree-tops. Like other crustaceans, hermit crabs have an exoskeleton, but it only covers their head, legs and claws. Their long soft abdomens are are curved like a cashew, with the last pair of limbs working like a clamp, allowing the crab to stay in the shell. As they grow, every so often they must move house, hopping in and out as quickly as possible.

Hermit crabs probably earned their name from our assumptions that life in a cave-like shell is reclusive and lonely. However, this couldn’t be further from the truth – hermit crabs are downright sociable and community-minded. In fact, they prefer to live in colonies of 100 or more. As well, they often generously share their home with a variety of other species, including fuzzy hydrozoans (ie. snail fur), sponges and flashy anenomes (as pictured right, courtesy of Daily Kos). Hermit crabs play an important role in their community, scavenging dead animals and grazing on the microalgae that growns on the shells of their neighbours.

This model citizen of the benthos was knitted for our crafted seafloor by the talented and elusive Miss Knit, using a Hansigurumi pattern. It is only about two weeks until we celebrate World Ocean Day - now is the time to finish up your critter and pop it in the mail!

Friday, May 23, 2008

You Know What They Say About Glass Houses...

At over half a billion years old, sponges are the oldest multi-cellular animals on the planet. Scientists have identified thousands of species, and believe there are many more yet to be found. Indeed, the NOAA Ocean Explorer recently discovered a new marine sponge, dubbed “Bill Clinton,” as it apparently resembles the former US president’s hair-do.

Sponges have a very simple anatomy, and don’t form tissues or organs. But Hexactinellid, or glass sponges also boast some of the most complex skeletons known to science, far stronger than any feats of human architecture. These creatures use intricate arrangements of tiny needle-like shards of silica (known as spicules), layered with glue, to create their reinforced cage-like skeletons.

These unique skyscrapers of the sea provide excellent homes and make great nurseries for a wide range of fish, crustaceans, and other organisms. As a very slow growing species, glass sponges are particularly vulnerable to destruction by bottom trawling. These crocheted specimens are happily safe from harm in the window of The Loop, in downtown Halifax, where they serve as habitat for a growing swath of crafted critters.

Friday, May 16, 2008

Happy Endangered Species Day?

With so many sea creatures at risk of extinction, it is heartening to hear that new species continue to be discovered. Actually, more new animals are found every year in marine environments than any other. But this is no reflection of ocean health – rather, it illustrates how very little we know about life in the ocean, especially the deep sea. In fact, global populations of marine species plummeted by 28% in just 10 years, according to the Living Planet Index.

Last summer, Canadian researchers from DFO and Memorial University rented a powerful submersible camera to explore the fascinating depths of Sable Gully. They came back with the most incredible photos! This exciting voyage also revealed several species not previously known to science, including this stunning file shell from the family Limidae. (Photos courtesy of DFO. Crocheted Limidae made by Morgan. )

The Sable Gully is a deep underwater valley located about 200 kilometres from the shores of Nova Scotia. Here on the edge of the Scotian Shelf, the sea floor suddenly drops over two kilometres, revealing a canyon almost 70 kilometres long and 20 kilometres wide. The Gully, now designated as a Marine Protected Area, is home to a rich and unique diversity of marine habitats and species. An integral part of ocean zoning, marine protected areas have a critical role to play in the conservation and protection of ocean life.

Tuesday, May 13, 2008

Voyage to the Bottom of the Sea

Look at this marine biodiversity! I feel all warm and fuzzy inside. It's just like Claire Nouvian described: "Down at the bottom of the oceans, there are forests of corals extending over hundreds of square kilometers, sheltering an infinitely rich and varied fauna. Sharks and cephalopods lay their eggs there; giant gorgonians offer their branches as promontories for echinoderms; delicate sponges welcome crustaceans and fishes."

But these animals don't just exist to be pretty. Marine ecosystems play a crucial role in life-sustaining global processes. The ocean provides carbon capture, climate change buffering, and coastal protection, among other functions. It also offers a staggering amount of food, pharmaceuticals and other stuff that is vital to our well-being. The ability for the sea to supply these essential "goods and services" depends on complex and mysterious relationships between organisms and their environments -aka marine biodiversity.

Come visit our marvelous and growing Northwest Atlantic sea floor. The Loop Craft Cafe is located on 1547 Barrington Street in Halifax, Nova Scotia. Thanks to everyone who has lent or donated sea creatures to the project so far. We look forward to your contributions!

(Bonus points for anyone who can pick out the lumpfish!)

Monday, May 12, 2008

"With fronds like these, who needs anenomes?"

They may appear a little… vegetative, but once you get to know them, sea cucumbers (Holothuria) are fascinating creatures. These pickle-shaped echinoderms lay on their side, using five rows of tube-feet along their body to get around. They make use of another set of feet around their mouth to gather particles of plankton and other organic matter.

Amazingly, sea cukes protect themselves from predators by expelling their internal organs out of their butts! This works to either frighten (disgust?) or satisfy the appetite of their predators, and they simply grow a new set of viscera over the next two to six weeks. This regenerative ability holds incredible medical potential, leading most recently to the development of artificial corneas. As well, a protein found in sea cucumbers may hold promise in the fight against malaria.

Despite a stodgy appearance, sea cucumbers are considered a delicacy in many Asian communities. Nicknamed ‘ginseng of the sea”, many believe they are endowed with aphrodisiac powers. In Korea and Japan, bits of sea cuke innards are eaten raw or pickled. The body is also dried and sold as beche-de-mer.

Holothuria tend to be vulnerable to overfishing- and as Asian markets overexploited stocks closer to home, markets have ventured further and further afield. Today there is a relatively new "exploratory" sea cucumber fishery here in Nova Scotia. Modified scallop dredges lift them off the sea floor, along with various other bottom dwellers. (Photos courtesy of The Intersection. Critter courtesy of Naomi.)

Thursday, May 8, 2008

The Metamorphosis

What a mug. Flounders aren’t born with such wonky eyes. When they hatch as larvae they swim in the usual fishy way, but, like all flatfish species, they undergo startling bodily changes at a certain age. One of their eyes migrates to the other side of the body, and they begin to swim around on one flat side. And you thought think human puberty was traumatic! (Photo courtesy of Jeff Rotman.)

Flounders live close to the sea floor, using sophisticated colour-changing pigments to blend in with their surroundings. Most flounders have relatively small mouths, and must hide patiently along the bottom, ambushing miniature meals of crustacean, shellfish, or polychaete worms.

Atlantic flounders turn up at supermarkets and on menus under many names, including Blackback, Dab, Fluke, Gray Sole, Lemon sole, Rusty flounder, Summer flounder, Windowpane flounder Winter flounder, Witch flounder, and Yellowtail flounder. However, they are naturally vulnerable to fishing pressure, and after a long history of overfishing, habitat damage and bycatch, most stocks remain depleted. You can read the SeaChoice assessment here, and browse the “Best Choice” list for sustainable seafood alternatives.

This fuzzy flounder recently turned up at the Loop Craft Café, where we are about to set up a Northwest Atlantic sea floor display in their front window. With just under a month until Ocean Day, now the time to get crafting, and help us populate our diverse, fibrous ecosystem. Check our wishlist and pattern resources along the right, or feel free to call us at the Ecology Action Centre, at (902) 446 4840.

Monday, May 5, 2008

Heaven on the half shell

"If you don't love life you can't enjoy an oyster; there is a shock of freshness to it and intimations of the ages of man, some piercing intuition of the sea and all its weeds and breezes. (They) shiver you for a split second.” So says novelist Eleanor Clark, and the marine team here at the Ecology Action Centre tend to agree, whenever we get the chance.

In Atlantic Canada, at the tip of its northern range, the Eastern Oyster (
Crossostrea virginica), has been found in warm, shallow bays and estuaries, along with the coves of the beautiful Bras d'Or Lakes in Cape Breton. As oysters die off, they form an impressive reef that can provide complex habitat for many organisms. As filter feeders, these crusty bivalves can also play a vital role in improving water quality. Unfortunately, many of Nova Scotia's native oyster reefs have disappeared as a result of introduced diseases, pollution, and dredging.

Lucky for sustainable seafood lovers, today there are several oyster farming operations in Atlantic Canada. Low-density farmed oysters have been given a “Best Choice” rating by SeaChoice, Canada's Sustainable Seafood program. Click here to read more about the assessment, and ShanDaph, a remarkable oyster operation in Merigomish, Nova Scotia (pictured left).

Though our crocheted specimen flaunts a pretty pearl button, Crossostrea virginica are not so renowned for their accessories. Many bivalves make pearls to seal off irritants in their shells, but only a few species polish them off with the nacre sheen sought for posh necklaces and earrings.