Just came across this - it has octopi in it, so is at least partly mollusc-related!!


Deep Sea Nursery Discovered Off Northern California

MOSS LANDING, California, September 3, 2003 (ENS) - Scientists at the
Monterey Bay Aquarium Research Institute (MBARI) have discovered a
unique undersea nursery on a deep sea ridge off Northern California
where groups of fish and octopus brood their eggs. The nursery area lies
near the crest of an undersea rise, almost a mile below the ocean
surface.

The undersea nursery was discovered and documented using MBARI's
remotely operated vehicle (ROV) Tiburon. Using video tapes from Tiburon
dives, the research team found that each summer, blob sculpin and deep
sea octopus gather together at the crest of the Gorda Escarpment, off
Northern California.

This is the first time that marine biologists have directly observed
deep sea fish brooding their eggs, and the first time that two
different types of mobile deep sea animals have been observed brooding
together in the same area. Scientists believe that the nursery
represents a new type of biological hot spot.

MBARI scientist Jeff Drazen presented these observations last week at
the Deep Sea Biology Symposium in Coos Bay, Oregon. His research is also
featured in the current issue of "Biological Bulletin."

"The sculpin nests look like large splotches of purple strewn across the
surfaces of boulders," says Drazen. "The parent fish is
usually resting on the seafloor near or on top of the eggs. When I first
saw this in the video, I was surprised because no one had ever
documented such behavior in a deep sea fish before."

Blob sculpin are typically about two feet long and shaped like large,
flabby tadpoles. Drazen estimates that some sculpin nests may contain up
to 100,000 eggs.

MBARI geologists first encountered these nursery areas in August 2000.
While performing geological surveys with ROV Tiburon, they noticed that
octopus and blob sculpin were common near certain cold seeps, where
hydrocarbon rich fluids seep out of the seafloor.

When they returned to the region in 2001, they brought along biologists,
who realized that the octopus were present in unusually large numbers.
On one dive, the ROV also brought up a rock sample which was covered
with eggs.

When Drazen watched videotapes of these dives, he realized both the fish
and the octopus might be brooding eggs. Drazen organized a third dive in
July 2002, to count the animals and their eggs and to make more
observations. The high densities of animals measured in certain areas
convinced Drazen that these nurseries might qualify as biological hot
spots.

Previously discovered biological hot spots in the deep sea, such as
hydrothermal vents and the tops of seamounts, have been related to
geological or topographic features that cause an increase the
availability of food.

The nurseries on the Gorda Escarpment may represent a totally different
type of hot spot, where physical conditions particularly favor the
development of eggs. Drazen points out that such areas are critical
habitat for the species involved.
  The scientists fear that these undersea nurseries could be endangered
by commercial trawling or longline fishing. Such fishing has expanded
into the deep sea as near-shore fish stocks have declined. Drazen
suggests that reproductive hot spots such as this might qualify as areas
to be protected from fishing.

From the great VERY Wet North,
Ross M.