in Context the SCotian Shelf - COINAtlantic

Benthic Organisms
Benthic invertebrate species include species that
live within the bottom substrates (infaunal) and on
the seafloor (epifaunal). Generally more is known
about species that are found on the seafloor.
Invertebrates: Infauanal and non-commercial
The non-commercial benthic invertebrate species
found in Nova Scotia’s waters represent many
billions of animals, stretching from the shallow
intertidal organisms to deep water abyssal species
(Breeze et al. 2002). Most of these species
are not well studied and not well described
beyond the intertidal zone (Breeze et al. 2002).
As mentioned previously work is underway to
classify benthic communities of the Scotian Shelf.
Examples of infuanal non-commercial invertebrates
found on the Scotian Shelf inclued various
polycheate worms. Epifaunal organisms include
certain echinoderms (starfish and sand dollars),
anemones, corals, sponges and tunicates. Research
is increasing on corals and sponges on the
Scotian Shelf.
Cold-water corals are suspension-feeding
invertebrates with feathery tentacles that capture
food particles from the water column. Unlike
their tropical counterparts, cold-water corals do
not have symbiotic algae and can live far below
the reach of sunlight. Many corals require a hard
substrate for attachment; however some species
can anchor in soft sediments. Corals can occur in
many shapes, sizes and forms and some species
can form reefs. They are slow growing and some
may be over 100 years old. On the Scotian Shelf,
corals are concentrated in areas with high current
activity (Breeze et al. 1997, Mortensen et al.
2006). Corals represent a varied habitat for other
organisms, such as fish, shrimp and sea stars.
They offer shelter from predators, a nursery area
for juveniles, and attachment substrate for other
organisms (DFO 2010b).
Around 25 to 30 species of corals have been
identified off the Atlantic Coast of Nova Scotia.
They can be organized in two major groups, hard
or stony corals (Scleractinia) and octocorals. Both
solitary and colonial (reef-building) forms of corals
are found along the slope of the Scotian Shelf
(DFO 2006). A live colony of the reef-building
coral, Lophelia pertusa, has been found at the
mouth of the Laurentian Channel on the Scotian
Shelf. The solitary cup corals are widespread
in soft sediments along the Slope and are also
found in basins of the Scotian Shelf.
Octocorals include sea pens, sea whips, sea fans
and “soft corals.” The largest octocorals on the
Scotian Shelf are the gorgonian corals: bubblegum
and seacorn corals. These corals prefer habitats
of hard sea bottom and attach themselves
to large rocks and boulders. They have only been
found in the channels between the banks and in
the canyons. Sea pens and small gorgonians are
found on soft sediments and are able to anchor
to them. A relatively high concentration of sea
pens has been identified near Middle Bank on
the Scotian Shelf (Kenchington et al. 2010).
Sponges are marine invertebrates that attach
themselves to bottom substrates. Sponges are
filter feeders and are generally found at depth
below 300 m. Sponges can provide substrate and
offer shelter for other organisms (DFO 2010b). A
unique and significant population of Russian Hat
http://coinatlantic.ca/index.php/state-of-the-scotian-shelf
19