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April 2003
Down from the
Mountains
by Berry Wijdeven
Picture if you will, a young German
palaeontologist, roaming the mountain ranges of Europe, examining the
fossilized remains of a giant sponge reef deposited some 150 million
years ago. Remnants of the reef can be found from Russia all the way to
Spain and Portugal. Portions have even been found in Newfoundland. They
were part of a giant reef system, 7,000 km long and up to 60 meters
thick which was the largest living structure ever created.
While the existence of the reefs had been known
for some time, little was known about their ecology, how the sponges
lived and interacted with their environment. These were the answers the
young palaeontologist was looking for as he examined the exposed
remnants of the giant reef, studying the thick layers of fossilized
sponge, searching for clues to ecosystems which had become extinct more
than 40 million years ago.
Then one day in 1996, the palaeontologist happened
upon an article which would change his life and bring him down from the
mountains. Published in 1991 by four Canadian scientists from the
Pacific Geoscience Centre in Sidney, BC, the article described the
discovery of anomalies picked up during sonar scans of the Hecate
Strait and Queen Charlotte Sound. According to the scientists, the
anomalies were sponge reefs.
Palaeontologist, Dr. Manfred Krautter, still
sounds slightly overwhelmed as he describes his first reaction to the
article.
“At first I couldn’t believe
it.” he says. “I was electrified. We
palaeontologists had thought they had died out”
Dr. Krautter contacted the scientists at the
Geoscience Centre and suggested a joint venture to study the reefs. He
received an enthusiastic response and by 1999 the team was ready to
start their study.
Just getting a glimpse of the sponges
wasn’t easy. Located at depths of 150 to 250 meters, the
reefs can’t be reached with scuba gear.
So the team secured the services of the research
vessel CCGC John P. Tully and the two-person submersible Delta. The sub
was cramped and cold, with water temperatures hovering around four
degrees Celsius at those depths, but the scientists were rewarded with
the opportunity to finally sneak a peak.
In July 1999, the sub, with Dr. Krautter on board,
made the first of 18 dives. For the first time ever, anywhere in the
world, living, thriving sponge reefs were being studied by direct
observation.
“It was like a time machine,”
says Dr. Krautter. “ Like a dive back millions of years. You
get in the sub, in the present time, dive down and arrive 140 million
years ago.” The journey didn’t disappoint.
Videos of the dives provide a glimpse of this
hitherto unknown world. As the sub descends it passes endless numbers
of jellyfish. Then it gets dark. Near the sea bottom at a depth of some
198 meters, the sub’s lights are turned on. At first, the
camera focuses on a section of muddy sea floor, but as the sub begins
to move, the sponge reef comes into view. Masses of white, ghostlike
shapes emerge. There are sponges everywhere.
Some look like giant wine goblets. Others have
multiple finger-like protrusions or bouquets of slender tubes. It looks
eerie, alien, and stunningly beautiful. Over the next three years,
using the sub, a remote controlled vehicle and side-scan sonar data,
the team discovered four reef structures covering about 700 km2 of
seafloor in Queen Charlotte Sound and Hecate Strait. The mounds are up
to 21 metres high and many kilometres wide. Radiocarbon dating has
determined the reefs to be 9,000 year old.
Sponges are among the oldest life forms on earth.
They have been found fossilized in rock layers 600 millions years old.
Sponges still flourish today with more than 7,000 known species in both
fresh and marine waters all over the world.
Unlike the soft sponges we sometimes find washed
up on the beach or those in our bathtubs, the sponges that make up the
reefs are siliceous or glass sponges that have a rigid structure
created by using silica dissolved in the water. The waters off the BC
coast have some of the highest silica content in the world. This silica
originates in feldspar deposits in the BC interior and is brought to
the coast as sediment in rivers and streams.
Each siliceous sponge can grow up to 1.5 meters
tall. The sponge walls are thin and brittle, two to three millimetres
in thickness, making them extremely fragile. Touch them and they break
apart. When a sponge dies, its skeleton becomes part of the structure
of the reef. Because the sponges are so delicate, the structure of the
reef is dependent on the sponge’s ability to trap sediment
for strength and support.
”If you have too high a sediment input,
the sponges won’t like it, they will die. And if it would be
too low, the structure will collapse. It’s a very balanced
system. And that’s just dealing with the sediment.
It’s also very balanced speaking about nutrients. There are
many, many factors playing together in forming this little niche.
That’s why it’s so unique.”
Though the reefs have survived for 90 centuries,
they have not escaped recent damage. The culprit? Bottom trawling.
“There’s a LOT of
damage,” says Dr. Krautter. “Before we did the
cruise in ’99, we studied all these side-scan sonograms and
based on this data we choose certain areas to go with the submersible.
When we came here and went down with the sub we couldn’t find
any sponge anymore. It had been erased, like a desert.”
According to Dr. Krautter much of the most
southerly reef has already been lost.
”… we know it is bottom
trawling, because we could see the trawl marks. We could see the trawl
marks on the side-scan and we saw it on the screen of the digital
camera.”
Damage to the reefs is impossible to restore. Once
a reef area is gone, it is gone forever. The reason for this is that
the sponges need firm ground to settle on. The scouring action of the
glaciers provided this solid base when the reefs were established
following the last age of glaciation. Since then, however, much of the
ocean floor has gradually been covered with a thick layer of sediment,
making it impossible for the sponges to anchor themselves.
For Dr. Krautter the saddest part is that bottom
trawlers shouldn’t even be on the reefs.
“Trawling makes no sense in these areas
because we saw a lot of fish in the reefs, but only juvenile fish.
Juvenile rock fish. It’s a nursery, a kind of kindergarten.
They use the niches, the caves, the areas between the sponges to hide
from predators. And after getting a certain size, they get out. If you
erase the reefs, you will absolutely erase the fish stock.”
In July 2002, the sponge reefs got a reprieve of
sorts. Robert Thibault, the Minister of Fisheries and Oceans, declared
the sponge reefs closed to bottom trawlers. These fishery closures are
a good start, but they lack permanence. Long-term protection is still
needed for the reefs.
Dr Krautter displays a lot of passion when it
comes to the sponge reefs. He is clearly anxious not to lose this
opportunity, an opportunity he never dreamed possible.
“These are the only siliceous sponge
reef systems in the world,” he says. “We have an
exceptional opportunity and maybe a last chance to learn more about
these "living fossil reefs" and their environment and therefore we
should use it!”
Years ago, a young palaeontologist started looking
for answers in the mountains of Europe. Now, the depths of Hecate
Strait may finally provide him with those answers.
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The
Trouble with Trolling
by Lynn Lee and Berry Wijdeven
Trolling. It’s considered by many to be
one of the least invasive methods of commercial fishing along the BC
coast. There are no nets involved, by-catch isn’t much of a
problem and there’s little impact on fish habitat. Fishers
are dependent on fish striking the lures, providing at least a
semblance of fairness.
So what then is the trouble with trolling? Well,
it turns out people sometimes confuse trolling with trawling. And
trawling, now there’s a whole different kettle of fish.
Trawling’s got “issues”. Bottom trawling,
commonly known as dragging, has come under attack for its impact on
fish habitat as the heavy weights and big nets crush and flatten the
sea bottom, damaging and destroying fish habitat and delicate ocean
life. Equally troublesome is the catch of a substantial volume of
undersized or unwanted fish, the so-called by-catch, while in pursuit
of the legal-sized targeted fish species. There are also mid-water
trawlers who don’t damage fish habitat but can still produce
substantial by-catch.
By now you probably get an idea why trollers
don’t want to be confused with trawlers. To further clear the
muddy waters, here is a brief description of these two commercial
fishing practises in BC. Stay tuned for upcoming issues to learn about
other coastal fisheries.
Trolling
First Nations people were the first on the coast
to troll for fish. Using dugout canoes, they would hold the fishing
line in their hand or wrapped around their paddle as they moved through
the water. Nowadays, commercial fishing boats with poles and multiple
fishing lines have replaced this traditional hand-lining technique.
Some boats deliver fresh salmon to the packing plants, packing ice to
chill fish caught over a 10-day trip. Other, generally larger trollers,
have flash freezers on-board, allowing them to freeze their freshly
caught salmon and stay out on the water for several weeks.
On the BC coast, commercial trolling for salmon
involves dragging up to six 300 metre long weighted stainless steel
fishing lines with multiple hooks behind a moving vessel. The fishermen
can be very selective and use knowledge about the behaviour of each
salmon species to adjust lures, fishing depth, fishing location,
fishing speed and other intuitive factors to catch the salmon of
choice.
North Coast commercial salmon trollers target all
five species of Pacific salmon: chinook, sockeye, coho, chum and pink,
depending on the numbers of each species expected to return to major
spawning streams. Of the different commercial methods of catching
salmon (gillnet, seine and troll), trolling provides the highest
quality salmon to markets. Although the majority of the BC troll fleet
targets salmon, trolling is also used to catch albacore tuna further
offshore and sometimes to catch lingcod and halibut. The BC
recreational fishery also uses trolling to catch salmon and halibut.
Recreational fishers can only use one single hooked line per fisher.
Trawling
Trawlers are industrial fishing vessels designed
to catch a lot of fish in one fell swoop. The boats drag a long
wedge-shaped net that narrows into a funnel shaped bag called the
“cod end”. On an otter trawl, the mouth of the net
is kept open by water pressure on two “otter doors”
situated on either side of the net. As the net is dragged along, fish
in front of the net are forced into the cod end. Different sized nets
are used depending on the fish species targeted in order to allow
undersized fish to escape. Trawl tows can last for up to 3 hours.
Trawlers can drag a net in mid-water (pelagic
trawling) and/or along the seafloor (bottom trawling). Mid-water
trawling is used to catch fish like hake that school in large groups
within the water column. Bottom trawlers target bottom-dwelling fish
like cod, sole and flounder. In BC, trawl nets are often fitted with
heavy pieces of rubber tire that roll the net along rough, rocky
seafloor. There are also smaller otter and beam trawls used to catch
shrimp. As their name suggests, beam trawlers use a metal beam instead
of otter doors to keep the mouth of the net open. They also have a
“tickler chain” in front of the net to cause shrimp
to jump up out of the soft bottom. In “dredging”,
nets with chain-mesh bottoms are dragged through soft bottom to catch
scallops (common on Canada’s East Coast).
Trawling provides high volume, lower quality fish
to markets. An otter trawl can bring in 60 tonnes (12,000 lbs) of fish
or more in one haul of the net. Good skippers can generally target and
capture the fish species they are after, but it is impossible to avoid
at least some bycatch. At times, trawlers can be responsible for a lot
of bycatch, including fish and shellfish that have no commercial value,
undersized commercial fish and commercial fish that they cannot retain
either because they are not allowed to keep them or because they are
over allotted quotas.
Then there is the habitat issue. Trawlers have a
big impact on the sea bottom. Everything in the path of the trawl net
is disturbed and all animals at or near the bottom are removed or
destroyed. Although some of these animals are quick to re-colonize a
trawl area, many are slow to return and, if an area is constantly
disturbed, some may never return.
As you can see, there’s a sea of
difference between trolling and trawling. They just sound the same. And
for trollers, that’s a bit of a drag.
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Save
the Sponge
by Lynn Lee and Berry Wijdeven
On July 19th, 2002, the Minister of Fisheries and
Oceans, Robert Thibault, announced that the four sponge reef areas in
Hecate Strait and Queen Charlotte Sound would be closed to groundfish
trawl fishing. Fishing industry groups, including the Canadian
Groundfish Research & Conservation Society and the Groundfish
Trawl Advisory Committee, proclaimed their support for this action and
vowed not to fish the reefs again. Case closed, sponge reefs saved,
right?
Well, maybe. Fisheries closures are temporary,
defined in management plans that must be renewed on a yearly basis. If
sponge reefs are to receive meaningful long-term protection, they would
need Marine Protected Area (MPA) status with fishing activity
restrictions under Canada’s Oceans Act.
The difference? Marine Protected Areas are
proactive and planned with long-term objectives, while fisheries
closures are generally reactionary and short-term. MPAs are created
with active participation from interested and affected parties
including fishers and local communities, whereas fisheries closures are
implemented and maintained by government, with little or no community
involvement. And while fisheries closures tend to be isolated and
focussed on single or a few commercially important species, MPAs have a
broader focus that can deal with many species, habitats and ecosystems.
In short, MPAs can provide more secure, long-term protection.
While at the national level MPAs do not
specifically exclude any human activities in the Pacific Region
agencies have agreed that all MPAs should share minimum protection
standards prohibiting ocean dumping, dredging, and the exploration for
or development of non-renewable resources. There must also be a
specific prescription in each MPA to limit other human activities. In
the case of the sponge reefs, an effective MPA designation must
additionally prohibit harmful fishing activities such as trawling and
longlining.
A quick review of the Oceans Acts suggests that
the sponge reefs are ideal candidates for MPA status. Section 35 (1) of
the Act states:
A marine protected area is an area of sea the
forms part of the internal waters of Canada, the territorial sea of
Canada or the exclusive economic zone of Canada and has been designated
under this section for special protection for one or more of the
following reasons:
(a) the conservation and protection of commercial
and non-commercial fishery resources, including marine mammals and
their habitats;
(b) the conservation and protection of endangered or threatened marine
species, and their habitats;
(c) the conservation and protection of unique habitats;
(d) the conservation and protection of marine areas of high
biodiversity or biological productivity;
(e) the conservation and protection of any other marine resource or
habitat as is necessary to fulfill the mandate of the Minister (of
Fisheries and Oceans Canada).
The sponge reefs are unique and should be
protected. If you are concerned about the continued well-being and
support their designation as MPAs, your voice will make a difference.
Please send your valuable opinions to:
The Honourable Minister
Robert Thibault
House of Commons
Wellington Street
Ottawa, ON
K1A 0A6
No postage is required.
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