| Home
Table 1. Habitat characteristics of strata sampled in the
Hudson-Raritan Estuary, 1992-97. (See Figure 1 for boundaries and areas
of each stratum.) |
|
Stratum |
Depths (m)a |
Sedimentsb |
Salinity Range
(ppt)a
|
Dissolved Oxygen
Range (mg/l)a |
Temperature
Range (°C)a |
Currentsc |
Habitat Types/
Structure |
Dominant Benthic
Community Typesb |
| 1- Sandy Hook Bay |
3.5-10.0 (avg. = 6.2); deepest to east and off Sandy Hook
Point |
>50% silt-clay, except nearshore. Moderate to high chemical
(toxic metals and organics) contamination. |
~15-27 |
2.0-13.0; avg. = 8.7 |
0.3-23.8; avg. = 11.1 |
~<0.6 knots; north-south |
Protected. Gradual (<1%) slope, except abrupt shoals parallel
to Sandy Hook. Ulva, other algae, redbeard sponge, and terrestrial
plant debris common in fall. |
Numerically abundant infauna, often including Ampelisca
abdita, northern quahogs, softshells, and blue mussels. |
| 2- Raritan Bay |
3.3-14.0 (avg. = 6.6); deepest near Raritan Channel |
>50% silt-clay in and west of Keyport Harbor and near
Earle terminal channel; gravelly coarse sand to silty sand in between and
in shallower areas. Moderate to high chemical contamination in silty areas. |
~16-26; lowest to southwest |
3.6-13.2; avg. = 8.9. |
0.0-24.8; avg. = 11.0 |
~<0.7 knots; east-west |
Semiprotected. Flat, gradual (<1%) slope; the 3-m trawl
depth limit excludes much of the wide shallow area off the New Jersey coast,
especially to the west; Raritan Channel is along the north boundary. |
Patchy abundance, lowest to west. Ampelisca abdita often
common in deeper, siltier areas near Raritan Channel; patches of Atlantic
surfclam, northern quahog, and softshell abundance. |
| 3- Lower Bay |
3.3-13.8 (avg. = 6.6); deepest in West Bank borrow pits and
near channels |
Sand, except mud in borrow pits and deepest areas near Raritan
Channel and west of Old Orchard Shoal. Moderate chemical contamination
in silty areas. |
~16-29; lowest to west |
5.1-13.8; avg. = 8.9. |
0.0-26.1; avg. = 11.1 |
~<0.7 knots, except near Chapel Hill Channel; east-west,
but north-south near West Bank |
Partially exposed. Gradual (<1%) slope, interrupted by
borrow pits north and south of West Bank, bordered by channels south and
east. Sponge patches in western areas. |
Overall numerical abundance variable, lowest on flats off
New Dorp Beach. Ampelisca abdita, other amphipods, bivalve mollusks,
and polychaetes abundant in deeper, siltier areas along southern boundary. |
| 4- Romer Shoal, Flynns Knoll, Swash Channel |
3.5-9.0 (avg. = 7.0); deepest in Swash Channel. |
Coarse to medium sand with shell. Low sediment chemical contamination. |
~15-30 |
5.0-12.4; avg. = 8.8. |
0.9-23.7; avg. = 11.1 |
~0.4->2.5 knots, generally northwest-southeast and east-west |
Exposed to the sea. Two shoals split by the Swash Channel,
bordered by three channels. Blue mussel beds are common. |
Overall abundance highest on Romer Shoal, <1000 ind./
m2 elsewhere. Blue mussels and Atlantic surfclams common. |
| 5- East Bank |
4.0-22.0 (avg. = 7.5); deepest near Ambrose Channel and seaward
of East Bank |
Coarse to medium sand, and gravelly sand with shell near
Breezy Point. Low chemical contamination. |
~20-31 |
5.0-12.4; avg. = 8.8 |
0.6-23.0; avg. = 11.2. |
~0.2-2.0 knots, generally northwest-southeast |
Exposed to the sea. Complex bathymetry including shoals and
natural and dredged channels. Blue mussel beds are common. |
Overall abundance highest near Breezy and Norton Points because
of blue mussels. Atlantic surfclams common elsewhere. |
| 6- Gravesend Bay, Narrows, West Bank |
4.3-26.0 (below the Narrows); avg. = 10.1) |
>50% silt near the Narrows and West Bank borrow pit; fine-medium
sand to silty sand elsewhere. Low chemical contamination. |
~19-29 |
5.0-12.0; avg. = 8.7 |
0.2-22.9; avg. = 11.2. |
~0.2-> 2.0 knots, north-south |
Semiexposed. Seabed rapidly (>5%) slopes into main Hudson
River mouth channel; West Bank shoal and several borrow pits to the west. |
Overall abundance variable. Ampelisca abdita moderately
common; blue mussels abundant near West Bank; polychaetes common in deeper,
siltier areas. |
| 7- Ambrose Channel (~600 m wide, ~7 km long)d |
6.5-22.3 (avg. = 17.1); dredged to ~14 (45 ft) |
Medium-coarse to gravelly sand. Low chemical contamination. |
~21-31 |
5.0-11.7; avg. = 8.5 |
1.7-22.3; avg. = 10.7. |
~0.5->2.0 knots, within channel |
Mechanically dredged to maintain authorized depth. Slopes
increase at sides of channel. Accumulations of trash common in the western
reach. |
Overall abundance generally low, with spotty settlement of
polychaete Asabellides oculata. |
| 8- Chapel Hill Channel (~300 m wide, ~7 km long)d |
6.6-15.2 (avg. = 10.3); dredged to ~9 (30 ft) |
Variable sands. Low chemical contamination. |
~20-30 |
5.9-11.6; avg. = 8.6 |
1.1-23.7; avg. = 11.4. |
~0.5-1.3 knots, east-west across channel |
Mechanically dredged to maintain authorized depth. Slopes
increase at sides of channel. Rocks are found in some places. |
No data, but probably similar to Ambrose Channel. |
| 9- Raritan Bay Channel (~265 m wide, ~16 km long)d |
9.4-15.2 (avg. = 13.0); dredged to ~10.5 (35 ft) |
Variable, silt-clay in west reach to mixed mud, gravelly
sand, and sand in east reach. Moderate to high chemical contamination. |
~20-29 |
5.0-12.0; avg. = 8.5 |
0.0-24.3; avg. = 10.9. |
~0.0-0.7 knots, within channel. |
Mechanically dredged to maintain authorized depth. Slopes
increase at sides of channel. |
Overall abundance low. Ampelisca abdita sometimes
a dominant taxa. |
a Channel characteristics are from National
Ocean Service (1995).
b Sediment and benthic community descriptions are from the Cerrato et
al.(1989) 1986-87 survey and Squibb et al.(1991).
c Current data from National Ocean Service (1994).
d Depth and hydrographic data ranges are from 1992-97 Raritan
Bay bottom trawl survey database.
|