Welcome to the Jungle
• Jungle Beach • Photo Gallery
Nudibranchs, otherwise known as sea slugs, were
the focus of Intertidal Explorations at Jungle
Beach. Nudibranchs are marine snails, relatives of abalone and limpets,
who have evolutionarily lost their shell.
Three different nudibranchs were found, in
addition to a plethora of cosmic creatures hiding under rocks and in
crevices – blood stars regenerating arms, shore crabs smaller
than little fingernails, red rock crabs live and their moults,
decorator crabs the texture of sea weed, bright green shrimp holding
eggs, light bulb tunicates, little octopus and dens, and flowing
ribbons of nudibranch eggs. A funny little fish called a grunt sculpin
was a highlight of the morning, being rarely seen in intertidal areas.
Thanks to the twenty-odd adults and children who came out to enjoy the
morning low tide!
For those who are curious about nudibranchs,
they come in a diversity of shapes, sizes, colours and patterns such
that they defy “typical” description. Feeding on
sponges, bryozoans, hydroids, tunicates and barnacles, particular sea
slugs are often associated with certain food types and sometimes, they
even look like their food! At Jungle Beach, we found a tiny red sponge
nudibranch which looks like and feeds on velvety red sponge.
The word nudibranch means “naked
gills”, referring to the fact that their gills are on the
outside of their bodies. Over 200 species of nudibranchs call the
Pacific Northwest their home so keep your eyes peeled next time you are
on the beach at low tide!
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Terebellids in Tlell
• Tlell • Photo Gallery
It’s the stuff of
nightmares…if you are a small larval creature travelling in
the whims of ocean currents. Contact with a seemingly harmless tuft of
feathery tentacles could mean sudden death in the jaws of the
terebellid tube worm! Okay – so maybe the gaping maw is no
more than 3mm across but when you are a larva measured in micrometres,
that’s scary!
Terebellids are a group or segmented worms which
live in tubes – perhaps you have seen their better known
cousins, the red tube worm with bright red and white-banded
“tentacles” (cirri) and white curvaceous tubes,
attached to the docks around town.
Unlike the feather dusters who secrete their own
tubes, terebellid worms secrete a cement-like substance which they use
to glue pieces of sand and shell together, much like a tile mosaic!
Balance is necessary in their place of residence since they must live
at a tide level where the sand around them is stirred up enough for
them to build with, yet where it is calm enough that their fragile
houses are not destroyed by ocean waves.
Reproduction involves releasing large amounts of
sperm and egg into the water all at once (broadcast spawning), which
then find one another in the water column and create a fertilized egg.
This then develops into tiny larva which is attracted to settle down
when it comes in contact with the cement-like secretions of its
parents. In this way, terebellids tend to stay together in one big
happy extended family!
This past weekend, twenty people tiptoed in
gumboots, sandals and running shoes, down the breakwater in front of
Dress of Les in Tlell, to visit the world of their marine neighbours at
low tide. “Coral heads” of fragile terebellid
colonies greeted them along with 22-armed sunflower stars, pipefish,
leather stars, sea slugs and sea anemones. Camouflaged in tidepools
were juvenile sole who have painted on themselves a perfect imitation
of the sandy bottom, and decorator crabs who encourage encrusting
sponges and kelp to grow on their shell in order to blend into their
surroundings.
If you go to visit the terrible terebellids in
your frontyard, remember to take care where you walk - although they
appreciate visitors, they and their intertidal friends are easily
damaged under heavy footsteps!
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Shorekeepers' Survey • Port Clements
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Soaking it up at Skonun Point •
Masset • Photo
Gallery
A Giant Pacific octopus smaller than my hand was
the star attraction of the morning low tide at Skonun Point on Sunday
August 19th. The yearling emerged from its dark hiding place in the
crevice of a rock, slithering quietly on the surfgrass towards a
tidepool. In the quiet of the water, it propelled itself towards a
cobble, curled down on all eights, and morphed colour to match the
light mottling of the sandy bottom. There it sat for all 30 of us to
admire.
The Giant Pacific octopus is the largest of its
kind anywhere in the world – The largest reputed to weigh
over 600 pounds! Believe it or not, the average octopus only lives 3 to
5 years. At about 3 years of age, the females are mature. She mates
(usually in autumn), finds a sheltered crevice for nesting, and hangs
30 to 100 thousand eggs in beautifully beaded strings from the ceiling
of her den. She then hunkers down for the next 5 to 6 months, fanning
and defending her brood. During this time, she ventures no more than an
arm’s length from her den and thus cannot hunt and eat. By
spring, when the eggs are ready to hatch, she has weakened and dies.
Over a period up to a week long, her entire
brood hatches out. The newly freed juveniles, a quarter-inch long, run
the gauntlet of hungry mouths for about 2 months during the
free-swimming planktonic stage of their lives. Once they settle to the
ocean floor, they eat and they grow. After a year and a half, the
little guys weigh just over 2 pounds – In less than 3 years,
they may weigh up to 38 pounds! A truly impressive rate of growth
fuelled by an equally impressive ability to eat! Hunting primarily
under cloak of night, the voracious octopus prefers a diet of crabs,
shrimps, scallops, clams and snails. An octopus den is often revealed
by the jumble of the shells tossed out the door after dinner! As there
is no free lunch in nature, even the cunning octopus must beware of
predatory sea lions, seals, sea otters, dogfish, lingcod, larger
octopuses and humans.
In the octopus’ garden of boulder,
bedrock and tidepools at Skonun Point, clumps of feather duster
tubeworms, encrusting sponges, blood stars, ochre stars, colonial
tunicates, sculpins, nudibranchs, shrimp and juvenile sole patiently
waited for the tide to flood back in, whence they could continue to
breathe, eat and play under the caress of saltwater.
Intertidal Explorations was
sponsored by the World Wildlife Fund Canada throughout the low low
tides in late spring and summer 2001. In total, over 100 Islanders and
visitors of all ages ventured out to visit their intertidal neighbours!
I encourage everyone to continue exploring the wonderfully rich and
diverse intertidal areas around the Islands. Be aware of the delicate
creatures under your footsteps and marvel at what you will discover!
