Meet your HAPC  NEARSHORE WATERS HABITATS, SPECIES AND CHALLENGES
THAT JOYOUS RAGING INTERFACE OF GAEA AND NEPTUNE

Subtidal Unconsolidated Sediments:
Unconsolidated bottoms are subtidal extensions of intertidal fine grained flats.

Sublittoral fringe, a narrow zone from the low intertidal to – 5 meters below
mean low water.  High diversity and abundance of invertebrates, high benthic
chlorophyll and a reduced number of grazers. 

Subtidal Mixed Coarse.
Shallow habitats comprised of cobble, gravel and boulders. These habitats are never exposed to the atmosphere. The wave energy is moderate to high. Numerous species of macroalgae.

Subtidal Ledge: 
Stable bedrock habitats that are never exposed to the atmosphere
during low tides. Subtidal ledge contains cracks, crevices, vertical walls and overhangs.
Many habitats are located in high energy regions exposed to pounding ocean swells.

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Biogenic Habitats

Rockweed.  All intertidal zones with rocky substrates.   

Eelgrass Low intertidal and shallow subtidal

Kelp. Low intertidal and shallow subtidal. Moderate to high wave energy environments.
 They attach to ledge, boulder, and mixed coarse environments  up to 130 feet on the
mainland and off-shore islands of Maine, depending on the species, water clarity, and
predation pressure.

DEP Habitat Ranking
Marine habitats are ranked  from high to low sensitivity to disturbance and development activity. 
These rankings should be used to discourage activity in habitats with a higher ranking and alternatively, 
redirect activity to habitats with a lower ranking. 

Activities taking place in habitats with a high and moderate ranking should receive a greater level of scrutiny in the permitting process. It may also be used to justify compensation for the loss of functions and values from
permitted activity.

Rank marine habitats according to ecological and commercial functions and values as well as the habitat's sensitivity to perturbations. Rankings are determined by marine biologists in the Division of Environmental Assessment. Based on scientific research and our knowledge of intertidal and shallow
subtidal marine environments.

DEP habitat ranking is based on habitats having one or more of the following attributes:

A. Nursery ground for commercial species
B. Primary production / oxygen production
C. High diversity
D. High primary and secondary production
E. Shelter
F. Structure for attachment of settling larvae
G. Food resources for one or more functional groups
H. Variety of functional groups represented
I. Sediment and nutrient sink and/or source
J. Nutrient recycling
K. Production and export of detritus
L. Habitat dependent species
M. Rare or endangered animals
N. Rare or endangered plants
O. Foraging areas for shorebirds and/or wading birds
P. Shorebird roosting and/or staging areas
Q. Supports terrestrial birds
R. Supports terrestrial mammals
S. Reduces coastal erosion
T. Supports commercial fisheries
U. Supports lobster fishery
V. Supports tourism industry
W. Geographically isolated and rare populations of species
X. Haul out and pupping sites for gray and harbor seals
Y. Foraging areas for waterfowl and/or seabirds
Z. Nesting habitat for endangered birds (e.g. piping plover, least tern)
AA. Supports anadromous fish

Beaches and tideflats
http://mainegov-images.informe.org/dep/blwq/vol1pt2.pdf

http://mainegov-images.informe.org/dep/blwq/vol1pt3.pdf

What are Subtidal Unconsolidated Sediments?
Unconsolidated bottoms are subtidal extensions of intertidal fine grained flats.
Like intertidal flats, sediments are composed of fine clays, silt, mud, sand, gravel and
organic matter. They receive replenishment of sediments from the same terrestrial
sources as intertidal flats. Subtidal unconsolidated sediments occur in the same areas as
intertidal flats but extend far offshore. Some intertidal ledge habitats and boulder
beaches blend into unconsolidated sediments in the subtidal.

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What are the Functions of Subtidal Unconsolidated Sediments?
Subtidal shallow sandy regions have many similar functions to intertidal mud flats
but they are a more diverse and productive habitat. Shallow subtidal soft bottom
communities in Portland Harbor support as many as 120 - 36,380 animals / m2 (Larsen,
Johnson, and Doggett 1983). Benthic sediments are homes to billions of microscopic
diatoms and bacteria. Diatoms, single-celled algae, convert nutrients into organic matter,
oxygenate the sediments and provide food for herbivores. Bacteria feed sediment
deposit-feeders and break down organic matter releasing nutrients back into the water
column. 

Animals that contribute to the ecological health of the subtidal community
include, horseshoe, hermit and mud crabs, polychaete and oligochaete worms,
amphipods, isopods, snails, bivalves, mysid and sand shrimp, brittle and sea stars, sea
pens, cumaceans, sand dollars, threespined stickleback, mummichug, alligator fish, rock
gunnels, longhorn sculpin, lumpfish, anemones, cusk, hagfish, tautog, redfish, wolffish,
cunner, shannies, rocklings, grubbies, rock eels and flounder (Larsen, Johnson and
Doggett 1983; Brown 1993; USF&W 1980; Wippelhauser et al. 1997). Eelgrass
frequently covers shallow zones adding to the structure and productivity of shallow
subtidal regions. Sandlance, an extremely important food resource for fish, mammals
and birds, inhabit sandy sediments inshore to the continental shelf (USF&W 1980).

The sublittoral fringe, a narrow zone from the low intertidal to – 5 meters below
mean low water, has a high diversity and abundance of invertebrates, high benthic
chlorophyll and a reduced number of grazers. Thousands of shrimp and amphipods take
refuge here as the tide recedes. The zone is a nursery area for mysid shrimp, amphipods,
wrymouth and other marine animals. This region is known to support populations of
priapulid worms, quahogs, clams, and oysters (Les Watling, personal communication).

What are the Permitting Issues of Subtidal Unconsolidated Sediments?
· No physical structures or fill should be permitted in subtidal environments. Filling
may violate Maine's water quality laws (see Maine's Water Classification Act) or
smother productive habitats. Any activity that would disturb shallow subtidal
communities, alter sediment type, or shade subtidal habitats, especially in the
sublittoral fringe, should be avoided.
· Temporary impacts to subtidal communities, as in the case of dredging and trenching,
may be permitted as long as the sediment type will not be changed and the
community can be expected to return to its original condition within a few years time.
· Dredging should be avoided or managed in a careful manner by conducting chemical
sediment core analysis before permitting any activity.

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What is Subtidal Mixed Coarse?
Subtidal mixed coarse is shallow habitats comprised of cobble, gravel and
boulders. These habitats are never exposed to the atmosphere. The wave energy is
moderate to high. Cobbles are rocks ranging between 2.5 - 10 inches in diameter. The
surf can overturn the smaller rocks. Boulders are 1-10 ft in diameter. Mixed coarse
habitats dominated by boulder fields are stable habitats. Boulders can not be overturned
by waves except by extremely powerful storms. Gravel are small rocks (1-2.5 inches in
diameter) that are constantly shifting in the surf. Little information is known about the
ecology of subtidal cobble, gravel and boulder habitats. Rocks, especially larger
boulders, may be covered by numerous species of macroalgae.

Where is Subtidal Mixed Coarse?
Mixed habitats are often located seaward of moderate and high energy intertidal
ledge, boulder, cobble and gravel habitats. Cobble habitats make up only 2- 10 % of the
shallow subtidal habitat in Maine (Brown 1993).

What are the Permitting Issues of Subtidal Mixed Coarse?
· Avoid permitting any activities in cobble, gravel and boulder habitats.
· Avoid permitting any activities that remove algal communities.
· Water dependent structures should be place in areas that will not shade algae or
indirectly impact algal beds. If unavoidable, structures should be as narrow as
possible, as high as possible and oriented as close to north-south as possible (see
eelgrass for guidelines). Avoid permitting activities where boat traffic can shade or
scour beds.
· Survey areas for lobsters. Lobsters may concentrate in kelp beds or under boulders
and cobbles.
· Avoid sediment disposal on or around subtidal mixed coarse habitats. Avoid
activities that will resuspend sediments around habitats.
· Dredging should be avoided or managed in a careful manner by conducting chemical
sediment core analysis and functional assessments before permitting any activity.
· If applicable, determine if current velocity, tidal flows, wave energy or water clarity
will be altered due to the proposed activity. If so, design project to minimize physical
changes.
· Physical barriers should only be permitted in emergency situations.
· Discharges of freshwater or pollutants should be minimized around subtidal habitats.
· New developments in the adjacent upland should maintain pre-development levels of
ground water seepage and eliminate increases of stormwater runoff.

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What is Subtidal Ledge?
Subtidal ledge is stable bedrock habitats that are never exposed to the atmosphere
during low tides. Subtidal ledge contains cracks, crevices, vertical walls and overhangs.
Many habitats are located in high energy regions exposed to pounding ocean swells.
Ledge habitats slope to the seafloor and often blend into boulder fields or soft
unconsolidated bottoms. Algae and animals colonize free space on the ledge and often
form multiple layers of organic material. In cold winters, ice can scour the ledge in
sheltered areas removing all layers of plant and animal growth.
Where is Subtidal Ledge Located in Maine?
Subtidal ledge is located off rocky shores on the mainland and offshore islands of
Maine. Intertidal ledge extends offshore creating subtidal bedrock features (see intertidal
ledge for distribution). Additional ledge habitat is found on offshore rock pinnacles in
the Gulf of Maine and near Mt. Desert.
What are the Functions of Subtidal Ledge?
Subtidal ledges have similar functions to low intertidal ledge habitats but they
have a greater diversity of algae and animals and complexity of horizontal and vertical
communities. Diatom mats cover ledge and feed herbivorous gastropods. Kelp beds, red
and green algae, and horse mussel communities create three-dimensional structures, trap
sediments and provide spatial refuges that result in a high diversity of marine species
including sea urchins, shrimp, worms, herbivorous amphipods, sea cucumbers, snails, sea
stars, limpets, nudibranchs, chitons, hermit crabs, spider crabs and other aquatic
organisms. Sessile suspension-feeding animals (e.g. sponges, polychaete tube worms,
tunicates) and predatory animals (e.g. anemones) layer on top of coralline algae and also
trap sediments creating additional complex communities of infauna species like bivalves,
brittle stars, and worms below surface waters. Mats of amphipods live within canopies of
red algae. Cracks and crevices provide spatial refuges from predation for invertebrates
and fish (Ojeda and Dearborn 1989; Mathieson et al.1991).

What are the Permitting Issues of Subtidal Ledge?
· Avoid permitting any activity in subtidal ledge environments.
· Avoid permitting activities that remove, disturb or change habitat structure.
· Water dependent structures should be place in areas that will not shade subtidal ledge
communities. If unavoidable, structures should be as narrow as possible, as high as
possible and oriented as close to north-south as possible (see eelgrass for guidelines).
Avoid permitting activities where boat traffic can affect algae and organisms.
· If applicable, determine if current velocity, tidal flows, wave energy or water clarity
will be altered due to the proposed activity. If so, design project to minimize physical
changes.
· Discharges of freshwater or pollutants should be minimized around ledge habitats.
· New developments in the adjacent upland should maintain pre-development levels of
ground water seepage and eliminate increases of storm water runoff.