Tuesday, June 10, 2008

Jellyfish Heaven

It is perhaps fitting that we have received so many wonderful crafted jellyfish for our Northwest Atlantic sea floor display. After all, jellyfish are an abundant source of food for many marine creatures. At 95 percent water, they aren’t packed with nutrients, but the sheer mass of jellies that can be found in one area makes them worthwhile prey for the likes of leatherback turtles, swordfish, salmon and tuna. In turn, many of these jelly-munchers become available as food for other animals – including the voracious homo sapiens.

Alarmingly though, scientists have warned that human impacts - from overfishing to climate change - are creating a sort of jellyfish heaven under the sea. These gelatinous wonders are extremely well-poised to fill important ecological vacancies left by fish higher on the food chain in the wake of disrupted marine food webs. Already, massive and long-lasting jellyfish “blooms” have begun to appear in various places where productive fisheries and diverse ecosystems once existed. These jelly swarms are astonishingly dense, disrupting shipping routes and bursting trawler nets.

As veteran University of British Columbia fisheries scientist Daniel Pauly has long advised, if we don’t change the way we fish, we’ll fish our way down marine food webs and end up dependent on a diet of “peanut butter and jellyfish sandwiches.” Indeed, Atlantic Canadians have already witnessed the beginning of this transition – since cod stocks collapsed, many fishermen have switched to invertebrates like lobster, crab and shrimp.

If you are near Halifax, Nova Scotia, please join the Ecology Action Centre and St. Mary’s University in welcoming intrepid author and adventurer Taras Grescoe, who will be reading from his new book about sustainable seafood called Bottomfeeder on June 11th and 12th. After a year-long sojourn around the globe in search of ethical seafood, he has concluded that we need to “give big fish a break” and eat lower on the marine food chain. While a diet of jellyfish is not likely to feed the world, choosing lower-trophic species such as mackerel, herring and sustainably farmed shellfish can help us to restore the dynamic biodiversity so crucial to ocean health - and to future generations of seafood eaters.

Sunday, June 8, 2008

Happy World Ocean Day!

Thanks on behalf of the Ecology Action Centre and the Loop Craft Cafe to everybody who stitched up a creature feature over the last two months or otherwise helped create our Northwest Atlantic sea floor ecosystem. Another round of thanks to those who came to visit our display on the Halifax Waterfront, where we joined up with dozens of other local ocean-related organizations to celebrate World Ocean Day. It was a fabulous sunny day and organizers counted more visitors than ever this year.

Over 300 school kids visited our Stitchin’ Fish sea floor, taking time to learn all about sea cucumbers, squid, crabs, bubblegum trees and other fascinating denizens of the deep. Unlike the remote floor of the Scotian Shelf, this crafted version allowed for lots of hands-on contact and tactile interactions. We can only hope that this cuddle time with our woolly marine ecosystem will take root in this next generation of fishers, scientists, managers, and seafood consumers – and help cultivate our deep and essential relationship with the ocean...

... because it’s kinda like President George W. Bush once said: "I know the human being and fish can coexist peacefully."

Wednesday, June 4, 2008

A Shark Among the Fishes

Let me guess… as you looked at this photo of a crocheted great white shark, you began to hum the theme from JAWS? That’s probably because this incredible animal, the largest of predatory fish, is also one of the most maligned by Hollywood.

Despite their notoriety, very little is known about the biology and habits of the great white shark, or Carcharodon carcharias. For example, where they mate and birth their young remains unknown. These torpedo-shaped predators are seen only rarely in Atlantic Canadian waters, with sightings and captures reported every couple years in the Bay of Fundy and off southwest and eastern Nova Scotia.

We do know that the great white is solitary hunter that can reach over six meters in length. They have one of the widest habitat ranges of any fish, and can tolerate temperature differences from sub-arctic to inshore tropical conditions. Their sleek evolutionary design has helped them rule the seas for over 400 million years, until humans usurped their role as apex predator, very recently. Many are caught as trophies for sports fishermen every year and even more end up caught as bycatch on pelagic long lines, trawls and gillnets.

A recent study out of Dalhousie University has revealed that North Atlantic great white shark populations fell by 79 percent from 1986 to 2000. They are now classified as a vulnerable or endangered species by many governments, including Canada, but much more needs to change on the water to ensure their survival. Depleted populations may take a long time to recover. Great whites grow slowly, and don’t reach sexual maturity until around 12 years of age.

If you are lucky enough to be in Halifax this Saturday, I’d like to invite you to come down to the Oxford Theatre for a 1 pm matinee showing of Sharkwater. It is a film by Canadian director Rob Stewart that features amazing shark footage and is helping to change our collective societal tune about sharks and ocean conservation issues. This film presentation is part of a weeks-worth of activities to celebrate the Ecology Action Centre’s Ocean Week.

Tuesday, June 3, 2008

One Fish, Two Fish, Unlucky Redfish

Check out this pretty little redfish, quilted by hand by the Ecology Action Centre’s own fisheries scientist, Jennifer Ford. Atlantic redfish, also known as ocean perch or rosefish, are members of the widely distributed Sebastes family, and closely related to the nearly 70 species of rockfish found off the Pacific coast. As you might expect, redfish are usually orange-red to scarlet in colour. They are a small fish, distinguished by their large cartoon-worthy eyes, a boney skull and jaw, and a fan of sharp, bony spines radiating around their gill cover.

“Ocean perch,” a popular market name for redfish, was invented by slippery seafood sellers in the 1930s. As freshwater yellow perch stocks declined, fishmongers responded by substituting with red fish fillets, which are similar in colour and could be sold twice as cheaply. Redfish is still a popular seafood choice in Midwestern US states, where most Canadian catches are sent, often after being frozen and filleted at sea.

Unluckily for the Sebastes family, all species are very slow-growing, late to mature, slow-moving, and easily caught. In the early days of the commercial fishery, redfish were caught by trawling along the seafloor during daylight hours. However, fishermen discovered that redfish move off the bottom at night to feed, and eventually switched to a midwater trawl, which is similar to a bottom trawl, except that it can be adjusted for use at different depths. More recently, combinations of bottom and midwater trawls have been used to allow fishermen to target redfish over a full 24 hour period.

Sadly, redfish populations around Atlantic Canada aren't doing so well these days. As the Department of Fisheries and Oceans (DFO) has reported, landings are down, recruitment is low, and estimates of abundance are substantially down. More sustainable seafood alternatives caught or farmed in Nova Scotia include bottom hook and line caught haddock, trap-caught shrimp, harpooned swordfish, low-density farmed mussels and oysters, rod and reel tuna (except Bluefin), and the ubiquitous lobster.

Monday, June 2, 2008

Children of the Sea Corn

Ganking a crochet technique applied to metal coat-hangers used to protect lady’s delicates from wrinkling, this gorgonian coral was crafted with pipe-cleaners and orange yarn during a marathon of circa-1993 Kids in The Hall episodes.

Primona resedaeformis, known locally as sea corn or rice crispy corals, are some of the most common species of coral found off the coast of Nova Scotia, often in association with Paragorgia arborea, crocheted and blogged earlier here. Like other gorgonian corals, sea corn generally grows in a bushy formation, with thin branching stems extending from a short main trunk. The branches are made up of colonies of individual polyps, which extend sticky tentacles called nematocysts into the current to fish for meals of plankton and dissolved organic matter.

As bottom hook and line fishermen have known for generations, these underwater coral forests provide vital habitat for a wide assortment of marine species, including commercially significant fish like pollock and redfish. The nurturing arms of sea corn offer protection from predation and currents, and even boost the feeding ability of other filter-feeders like brittle stars, who perch in the branches.

Much like our crafted version, Primona resedaeformis grow very slowly. They can live for several centuries, growing only a few centimeters a year. Over time, thin deposits of calcium carbonate, (CaCO3) accumulate on the coral branches, from the built up skeletons of successive generations of polyps. These layers can be examined much like growth rings on a tree, and contain valuable information about climate change, along with its alarming ‘sister crisis’, ocean acidification. (Photo courtesy of DFO.)

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.

Wednesday, April 30, 2008

Mighty Aphrodite

Believe it or not, the fuzzy creature pictured left is actually a worm, closely related to the earthworm. The great taxonomist Linnaeus named it Aphrodite aculeate. While one might hope he was appreciating the animal’s iridescent beauty, it seems that he was attempting a lame vagina joke.

The common name “Sea Mouse” likely arose because of Aphrodite aculeate’s resemblance to the furry rodent when washed up on shore or in fishermen’s nets. The sea mouse sports a dense mat of deep red or brown hairs on its back, finer iridescent blue-green bristles along its sides, and pink segmented flesh more akin to its earthworm cousin along its belly. (Photos courtesy of Paul Kay, the University of Massachusetts, and The Loop.)

This unassuming marine worm has lately been receiving a flurry of attention from optical engineers. It seems that Aphrodite’s spines are made up of very specialized hexagonal cells that are incredibly efficient at trapping light. In this way, the bottom-dwelling Sea Mouse captures the limited light available on the ocean bottom in her fancy bristles to create send signals to predators that suggest her bristles are poisonous (they are actually harmless). These photonic crystals are the first ever found in a living organism, and researchers hope to copy their structure and revolutionize fibre optic communications.

A further flurry of Sea Mouse attention has recently erupted here at the Ecology Action Centre, all because of the magic of local crochet wizard named Morgan. Not only has she crafted a magnificent specimen for our sea floor, but she has also provided a free, easy-to-read pattern! Click here to see the pattern and more information about the Sea Mouse on the Loop Craft Café’s great blog.

As the lyrical natural historian Sue Hubbell has pointed out, it is maybe fitting that Aphrodite aculeata, ''an advanced and specialized Polychaete, should echo the name the Greeks gave to the generative and creative principle that had emerged from the sea's depths.'' After all, as she notes, ''Aphrodite, the name, derives from the Greek word for sea foam, aphros.''

Tuesday, April 29, 2008

The Bubblegum Years

Ahhhh, coral. For most of us, the word conjures a warm breeze, a snorkel, and shallow aquamarine reefs. Tropical corals are some of the most beloved and well-researched ecosystems on a planet - after all, who doesn’t want to conduct research in a speedo?

It may be surprising to many that in the chilly, dark waters off the Atlantic Canadian coast, we host our own variety of coral communities. While scientists have only recently begun to learn about cold-water corals, fishermen along the continental shelf have been aware of their existence for generations. Known to bottom hook-and-line fishermen in Nova Scotia as “trees,” Paragorgia arborea and Primnoa resedaeformis, among other species, have long been regarded as vital fish habitat.

Paragorgia arborea (AKA Bubblegum trees) are considered to be the world's largest seafloor organism. Colonies can reach over seven metres high, and live for hundreds of years. They function as an oceanic treehouse, providing shelter for countless species of fish and invertebrates. Due to their upright nature and slow growth rates, Bubblegum corals are very sensitive to impacts from bottom trawling.

Back in 1996, a group of concerned fishermen on the South Shore of Nova Scotia formed an education and advocacy group called the Canadian Ocean Habitat Protection Society (COHPS). The group created a fantastic mounted display of collected coral specimens, and toured it around local schools, parades, and gatherings on the back of a pick up truck. ((Photos courtesy of the NOAA and Derek Jones.)

The important work of COHPS quickly reached the ears of the Ecology Action Centre and Dr. Martin Willison at Dalhousie University, and lead to the first International Deep Sea Coral Symposium in 2000. Today, there are two fishery closures and a Marine Protected Area designed to protect some of the coral on the Scotian Shelf.

For more about cold-water corals, keep your eyes on the Deep Sea News, as they are posting all kinds of fascinating coral stuff this week- from the latest science to the downright biblical.