N
OVEMBER
230.1
Figur 1.
Chann overc
bottom chann
2. Chann
1,000 about
11.49
3. Becau
whelk males
males 2009;
4. In Bu
mm, w autho
jeopar
R
18, 2014
1. Channele
re 2.15. Chann neled whelk t
ast days Bru m sediments,
neled whelk a neled whelk d
m
2
in both 1 t 10 whelks pe
to 17.42 per use of their lo
k are significa s, they tend t
s and sexually ; Peemoeller a
uzzards Bay M which is 20 m
rs conclude th rdy.
d whelk Bu
neled whelk Bu tend to bury in
uce 2006. Wh making them
are primarily h density in Nan
978 and 1981 er 1,000 m
2
fo 1,000 m
2
for ow reproductiv
ant Harding 2 o be targeted
y immature fe and Stevens 2
Massachusett mm greater tha
hat since fem
C
HAPT
usycotypus c
usycotypus can n sediment by
helk were fou m less vulnerab
harvested by t ntucket Soun
1 Davis and S or Narraganse
Narragansett ve potential a
2011; Peemoe for harvest w
emales, which 2013.
ts, channeled an minimum
males are harve Rhode Is
TER
2: E
COLOG
canaliculatu
naliculatus, ill y day, and be
und to spend o ble to harvest
trap or pot ge d Massachus
Sisson 1988. ett Bay, while
t Bay. and slow grow
eller and Stev which will lea
h will not lead d whelk reach
legal harvest ested before t
GY
us
lustration cour come more a
on average 65 t by dredge o
ear Bruce 200 setts was fou
. Sisson 1972 e Wood 1979
wth, managem vens 2013. W
ad to a female d to sustainab
hed sexual ma size Peemoe
they reproduc sh Manageme
rtesy of Brando active at night
5 of their tim r trawl Carri
06. und to be less
2 estimated a 9 found whe
ment concerns With females b
e-only harvest ble population
aturity at a she eller and Stev
ce, the fishery ent Plan, Vers
P
AGE
45
OF
37 on Fuller, 2014
t andor on clo me buried in
iker 1951;
than 5 whelk a whelk densi
lk densities fr s for channele
being larger t, leaving beh
ns Power et a ell width of 8
vens 2013; th y is likely in
73 4.
oudy,
ks per ity of
from ed
than hind
al. 9.7
he
P
AGE
46
OF
230.2
1. Knob
Bruc 2.
Knob as hig
cue tr
3. Work
recapt growt
heavy
4. Due t
knobb 2004;
Section
1. Ecosy
sustai civiliz
filteri in the
servic follow
filter
240.1
1. Shellf
estuar Need
phyto As ma
F
308
2. Knobbed
Figure 2.16. K bed whelk ten
ce 2006, whic bed whelk ar
gh as 15 cm se racking.
k done by Eve tured over a o
th due to shel y-shelled biva
o their low re bed whelk are
; Eversole et a
n 240. Ecos
ystem service in and fulfill h
zation would ng water duri
e water colum ces by reducin
wing provides feeding bival
1. Nutrient R
fish restoratio ries ability to
dles et al. 201 oplankton is a
ajor consume Management
whelk Bus
Knobbed whelk nd to associat
ch may expla e very adept a
ec
-1
Ferner an ersole et al. 2
one-month tim l loss from sh
alves such as q eproductive po
e highly susce al. 2008.
system Ser
s are processe human life, pr
cease to thriv ing feeding, f
mn. Reef build ng wave stren
s a description lve population
ReductionW
on, particularl improve wat
13. Asmus an key process w
ers of phytopl t Plan, Versio
C
HAPT
sycon carica
k Busycon car te with mud a
ain why they a at finding pre
nd Weissburg 2008 on knob
me span show hell chipping,
quahogs. otential, limit
eptible to ove
rvices Pro
es through wh roviding esse
ve Dame 201 for instance, p
ding bivalves, ngth hitting th
n of some of t ns.
Water Qual
ly for reef bui er quality thro
nd Asmus 19 within the ma
ankton, a loss on II
TER
2: E
COLOG
a
rica, illustratio and sand botto
are less likely ey through che
g 2005. Thei bbed whelk fo
wed no shell g which is a co
ted movemen r harvesting
ovision
hich ecosyste ntial life supp
12. Filter feed provide a wate
such as muss he shore and t
the known im
lity Improve
ilding species ough filtratio
993 conclude aterial exchan
s of filter feed
GY
ons courtesy of oms, and pref
y to enter whe emically med
ir slow movin ound that 95
growth, and th ommon occur
nt, slow growt Castagna and
ems and the sp port services w
ding bivalves er quality serv
sels and oyste thereby slowin
mportant ecosy
ement
s such as mus n of water by
e: “The intera nge between b
der concentra
N
OV
f Brandon Full fer live prey o
elk traps or po diated cues, ev
ng nature may of the indiv
hat 47 show rrence in whe
th, and large s d Kraeuter 19
pecies that ma without whic
s, by the proce vice by remo
ers, provide sh ng erosional p
ystem service
ssels and oyste y filter feeding
action between benthic and p
ations e.g., oy
VEMBER
18, 201
ler, 2014. over carrionb
ots. ven at flow sp
y assist in che viduals marke
wed negative s elk feeding on
size at maturi 994; Walker e
ake them up ch human
esses involve ving particula
horeline prote processes. Th
es provided by
ers, increases g shellfish
n mussel beds elagic species
yster reefs, m
14 bait
peeds emical
ed and shell
n ity,
et al.
ed in ates
ection he
y
s an s and
s.” mussel
N
OVEMBER
18, 2014 C
HAPTER
2: E
COLOGY
P
AGE
47
OF
373 beds, quahog aggregations in eutrophic systems provides a positive feedback mechanism for hypoxia
as phytoplankton are no longer heavily consumed by the bivalves Altieri and Witman 2006. 2.
Ecosystem services provided by oyster reefs has been summarized as: 1 production of oysters, 2 water filtration and concentration of pseudofeces, 3 provision of habitat for epibenthic invertebrates,
4 carbon sequestion, 5 augmented fish production, 6 stabilization of adjacent habitats and shoreline, and 7 diversification of the landscape and ecosystem Grabowski and Peterson 2007;
Coen et al. 2007. The National Research Council 2005 suggests a similar listing of ecosystem services, but includes enhanced water clarity improvement and alteration of hydrography in shallow
water ecosystems as it pertains to shoreline buffering.
3. Bivalves, as filter feeders, remove plankton and particulates from the water column—an adult soft-
shell clam can filter 4 liters of water per hour, and an adult Eastern oyster can filter as much as 14 liters of water per hour Bertness 2007; Rice 2001. For the Providence River, Rice et al. 2000
calculated a filtering capacity of 2 x 10
7
m
3
5.3 billion gallons per day in August by the quahog population. Newell 1988 calculated a 3.3 day clearance time
9
for the Chesapeake Bay in the late 1800s, but 325 days in 2007 due to the dramatic decline in oyster reef extent. Dame 2012 estimates
that Narragansett Bay has a bivalve clearance time of 25 days. 4.
Dense aggregates of bivalves can exert a controlling effect on phytoplankton abundance, resulting in improved water clarity and general eutrophication control Alpine and Cloern 1992; Asmus and
Asmus 1993; Dame 2012. As such, filter feeding bivalves serve as a critical link between primary production in the water column and the benthic ecosystem Bertness 2007; Higgins et al. 2011, 2013,
particularly since they do so on a consistent, long-term basis as permanent residents of the ecosystem, though impact on water quality may vary seasonally Dame 2012. Loss of this ecosystem service in
the Chesapeake Bay has been credited to have resulted in increased suspended sediments and decreased water clarity, and with those, a loss of eelgrass beds Newell 1988; Carmichael et al. 2012.
5. Bivalve aggregations—oyster reefs and mussel beds for instance—are significant elements of nutrient
recycling between benthos and water column Asmus and Asmus 1993; Coen and Grizzle 2007; Dame 2012; Grabowski and Peterson 2007; Prins et al. 1998; Sisson et al., 2011; Smaal and Prins
1993. Particulate organic matter is removed during filter feeding and returned to bottom sediments as feces and pseudofeces. Nitrogen is then recycled by sediment microbes where it is nitrified
10
for reuse by phytoplankton, or denitrified
11
and released to the atmosphere Giles and Pilditch 2006; Sisson et al., 2011; Higgins et al. 2013. Sisson et al. 2011 found that 21 of the organic N underwent
nitrification, being released back to the environment for biological uptake, and 12 underwent denitrification at an oyster reef in the Chesapeake Bay. The authors do note however, that rate of
nitrogen use and conversion were very seasonal September for their work as well as site specific, and some caution should be applied in transferring those rates to other places or times. Ammonia
excretion by bivalves is rapidly taken up in the water column by phytoplankton for growth Giles and Pilditch 2006; Newell 2004. In this way bivalve aggregates help control eutrophication while at the
same time rapidly recycling nutrients to promote continued phytoplankton growth that sustains the bivalve community. Newell 2004 notes that the biggest impact to benthic-pelagic coupling will
come from those species that maintain high clearance rates and produce excess pseudofeces. Smaal and Prins 1993 sum the process of benthic-pelagic coupling in shellfish aggregates as: 1 filtration
of large quantities of material from the water column, 2 reduction of phytoplankton with possible
9
Clearance time is the theoretical time needed for the total bivalve-suspension feeder biomass within an ecosystem to filter all particles from the entire volume of water in the aquatic ecosystem in question Dame 2012.
10
Nitrification is a naturally occurring process carried out by nitrifying bacteria in which ammonia, produced by the breakdown of organic materials, is converted to nitrites and nitrates which become available for use by aquatic
plants.
11
Denitrification is a naturally occurring process, performed by denitrifying bacteria, that converts nitrates back into nitrogen gas which can then be released back into the atmosphere.
