N
OVEMBER
7. Figur
Bay
8
but ha areas
share,
Soft-s Ganz
220.5
220.5
1. The b
south 90 bo
harve in 186
eelgra Rhod
Grizz chang
2. In a re
10 ft an abo
vs. 90 Carol
3. The h
marin
R
18, 2014
e 2.14 a sho note change
as seen a near Figure 2.14
, followed by shell clams w
1978, and as
5. Bay scallo
Figure 2.14. B
5.1. Ecology
bay scallop ha shore salt po
at scallop flee sting areas. O
65, but that es ass as a major
e Island wate le 2007; Carr
ging ecologica eview of scall
with firm bo ove bottom at
0 on the sed inas Fay et a
health of bay s na, with stud
ows wild harv in scale amon
r continuous d b, and hav
Point Judith were reported a
s scarce or ab
op Argopec
Bay scallop Ar as been histori
onds Brown 1 et in Rhode Is
Oviatt et al. 2 ssentially no b
r factor. Scall rs as a result
roll et al. 2010 al community
lop ecology b ttom, preferen
ttachment site diment interfa
al. 1983. scallop popul
ies finding th
C
HAPT
vest landings f ng graphs. H
decline. Harv e increased in
Pond Figure as scarce in G
bsent by Camp
cten irradian
rgopecten irrad ically abunda
1991. MacKe sland waters,
2003 note sca bay scallops h
lops however, of brown tide
0, as well as y make up Ca
by MacKenzie ntially with e
e as a partial r ace. The range
ations is often hat increased s
TER
2: E
COLOG
for 2007–201 Harvest from N
est from the s n recent years
e 2.14 c. Great Salt Pon
pbell 1961.
ns
dians, illustrat ant in Narraga
enzie 2008 with Greenw
allops as havi have been tak
, are consider e events in 19
from habitat arroll et al. 20
e 2008, it is eelgrass, whic
refuge from p e of the bay sc
n tied to the p seagrass abun
GY
13 for soft-she Narragansett
salt ponds dom s; Winnipaug
nd on Block I
tion courtesy o ansett Bay, th
reports that in wich Bay and
ing been most ken in decade
red to have be 985 and 1986
loss associate 010.
s noted that sc ch enhances ju
predation; 60 callop is Cap
presence or ab ndance equals
ell clams take Bay has dom
minate landin Pond provide
sland Russel
of Brandon Ful he Sakonnet R
n the late 180 Cowesett Bay
t abundant in s, suggesting
een largely el Brown 1991
ed with nutrie callops prefer
uvenile settlem mortality o
e Cod Massa bsence of eelg
s increased bi ent Plan, Vers
P
AGE
43
OF
37 en in Narraga
minated landin ngs from othe
es the domina ll et al., 1973;
ller, 2014. River, and the
00s there exist y being prime
n Greenwich B the loss of
iminated from 1; Coen and
ent loading an r shallow wate
ment and pro on eelgrass fro
achusetts to t grass Zostera
ivalve settlem sion II
73 ansett
ngs, er
ant ;
ted a e
Bay m
nd er 3–
ovides onds
the a
ment
P
AGE
44
OF
308 C
HAPTER
2: E
COLOGY
N
OVEMBER
18, 2014
Bologna and Heck 2000; Carroll et al. 2010. These authors suggest that seagrass presence reduces flow velocity, and promotes epiphytic growth that again reduces flow velocity, which enhances
bivalve larval settlement. Shriver et al. 2002 however, found that epibiont growth on scallop shell, which was correlated to increased nutrient availability e.g., eutrophic conditions, reduced both
scallop growth and Condition Index.
4. Scallop restoration success appears to be linked to eelgrass—presence improves scallop survival
Carrol et al. 2010. The authors note that Codium fragile, an introduced algae, can provide similar attributes to eelgrass for restoration, with no differences seen in scallop population recovery on Long
Island, New York between eelgrass only and Codium only sites. The authors do however state that it is unclear whether or not Codium plays the same ecological role as eelgrass over the long term with
regard to predator protection, or how hypoxia, which is common in Codium dominated waters, impacts scallop survival.
5. The green crab and blue crab Callinectes sapidus are the two most important predators of bay
scallops in shallow waters, while sea stars are important in deeper waters, and gulls on a tidally mediated basis Fay et al. 1983. MacKenzie 2008 reports oyster drill, knobbed whelk, mud crab,
tautog, scup, and eider as predators of scallops. Cow-nosed rays are noted to be an important predator to the south, and may become important in New England waters as warming continues as a result of
changing climate.
6. Scallop harvests in Rhode Island waters are sporadic and no trend is obvious. MacKenzie 2008, in a
review of scallop ecology on the Atlantic east coast, notes that there is indication that specificity in food selection by scallops may be a factor in the high year-to-year variability seen in recruitment
success.
7. It is of interest that 2010 saw a good set of scallops in Rhode Island waters, good enough to allow a
commercial harvest two years later as the scallops reached legal size in 2012. The good scallop set in 2010 is coincident with intense spring flooding, though any cause and effect is not readily known.
8.
Scallops were reported to be found on Block Island in Cormorant Cove and Trim’s Pond Russell et al. 1973, scattered in Great Salt Pond Ganz 1978, and scarce or absent in the pond by Campbell
1961.
Section 230. General Ecology—Gastropods
1. Whelks, often referred to as conchs, are gastropod molluscs that live in a coiled shell and resemble
large snails. Unlike bivalves, they are highly mobile, moving along by using a muscular foot that can be extended beyond the shell opening.
2. There are two major species of whelk found in Rhode Island waters: knobbed whelk Busycon carica
and the channeled whelk Busycotypus canaliculatus. Both exhibit a range from Cape Cod to central Florida Power et al. 2009. Magalhaes 1948 however, notes the channeled whelk to be as much as
5 to 6 times more common than the knobbed whelk in the Woods Hole area based upon data reported for 1911 by Sumner, Osburn and Cole, and that knobbed whelk appear to prefer shallower, warmer
waters; channeled whelk deeper, cooler waters.
3. Whelks tend to grow episodically, undergoing long periods of no growth, which makes management
relying upon average annual rates of growth potentially misleading Kraeuter et al. 1989. Power et al. 2009 report that whelk populations exhibit boom-and-bust cycles of abundance.
4. The largest whelks can be significant predators on bivalves, and have the ability to open the largest
quahogs Carriker 1951. Magalhaes 1948 reports crabs and gulls as common predators of whelks. 5.
Whelk tend to be sedentary, spending long periods immobile, interspersed with active times where average travel distance per day was found to be 18 m Magalhaes 1948. No evidence was found for
migration of either whelk species to offshore waters in North Carolina.
