Nowhere
Else on Earth
Protecting
the Unique Glass Sponge Reefs of Hecate Strait
 |
Glass
sponge (Heterochone calyx) |
Sponge
reefs were long thought to have disappeared with the dinosaurs,
but in 1991 Canadian scientists documented the world's first known
living sponge reefs off the coast of British Columbia, Canada. Now
that these unique reefs are under threat from trawl fishing, in
which heavy nets are dragged along the sea floor, many are calling
for the designation of the reefs as Marine Protected Areas.
The
sponge reefs are found in four separate locations over 700 square
kilometres of seafloor in Queen Charlotte Sound and Hecate Strait.
Lying in depths of between 165 and 240 metres, the reefs consist
of very dense populations of living hexactinosan (glass) sponges,
often more than one metre in height, creating mounds up to 19 metres
high and often many kilometres wide.
Sponges
are among the oldest known multicellular animals. They filter water
to extract food particles and live their whole adult lives in one
place much like a plant. More than 7,000 species of sponges are
alive today in both fresh and marine waters. Spicules that form
the sponge's skeleton are made out of different materials such as
silica, carbonate and protein fibres.
Glass
sponge reefs grow in deep water along the continental shelf, where
surface and seabed currents are strong and shelf waters are rich
in nutrients - making the region biologically productive. The reefs
are also home to an array of other species such as rockfish, annelid
worms, spider and king crabs, shrimp and prawns which use the openings
in and around the sponges. Sea stars and sea urchins are also common
in areas of dying sponges.
The
reefs are very susceptible to damage caused by trawl fishing. They
are currently protected by voluntary shrimp trawl fishery closures
and by regulatory groundfish trawl fishery closures. Despite these
efforts, Canadian and German scientists on a research voyage last
summer found new damage to the most pristine part of the reef, evidently
caused by trawl gear.
 |
| The
current locations of the glass sponge reefs in Hecate Strait
and the Queen Charlotte Sound, off the coast of British Columbia,
Canada. |
"We
saw large areas where trawlers had smashed the sponge reefs,"
said Dr. Mannfred Krautter, a palaeontologist and expert in sponge
reefs from the University of Stuttgart. "It was a shock to
discover that the northernmost reef in Hecate Strait has been damaged.
What was once the most pristine part of the reef will take thousands
of years to recover, if it is ever able to recover."
The
Canadian Parks and Wilderness Society (CPAWS) has called for immediate
action by Fisheries and Oceans Canada to impose fishing closures
to protect the Hecate Strait Sponges, and to start a process to
designate it as a marine protected area. Under Canada's Oceans Act,
the Minister of Fisheries and Oceans (DFO) has the power to establish
an emergency marine protected area that would immediately protect
unique features like these sponge reefs.
DFO
is currently monitoring the effectiveness of the fishery closures
and working to assess the area as a potential Area of Interest for
designation as a Marine Protected Area. The designation of a Marine
Protected Area is a process involving comprehensive consultations
with a variety of stakeholders including scientists, First Nations,
fishermen and the public. Based on the outcomes of these evaluations,
DFO will decide whether there is a need to take the next step to
protect the glass sponge reefs.
Sources:
Natural Resources Canada, University
of Stuttgart, Fisheries and Oceans Canada, Canadian Parks and Wilderness
Society. Photos
and videos courtesy of Natural Resources Canada and Universitat
Stuttgard
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