Details are limited to information relevant to
the UK marine habitats and species listed in the
Habitats Directive and the Birds Directive.
[pr] indicates that the paper is from a peer reviewed
journal or report
| Natura
2000 Habitats & Species |
Fishing Technique
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Effects
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Locations
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Reference
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REF: 91
Sandbanks
Seabirds
|
Shrimp
trawling |
Investigation
into the potential impact of a policy of immediately
discarding all by-catch from shrimp fisheries
in the North Frisian Wadden Sea.
Clearance rate of discards estimated by feeding
crabs and shrimps in aquaria. Traps baited
with discards used to examine fate in sublittoral
and take by birds assessed using combination
of counts, photography and video recording.
Underwater video revealed grey seals feeding
on discarded fish.
Authors conclude that 1988 seabird population
in the area would have easily been capable
of clearing the discards of moribund roundfish.
Harbour seals which were most likely to benefit
from flatfish discards.
|
|
Berghahn,
R. (1990) On the potential impact of shrimping
on trophic relationships in the Waden Sea. In:
Trophic Relationships in the Marine Environment.
Proc.24th Europ.Mar.Biol.Symp. Barnes,
M. & Gibson, R.N. (Eds). [PR] |
|
REF: 92
Shallow inlets and bays
Estuaries
Mudflats and sandflats
|
Aquaculture |
Study
on ecological effects of Manila clam cultivation
at the end of the cultivation phase (for all
stages see Reference 64)
Habitat effects. Organic enrichment
in net covered area. Short term sedimentation
rates were up to 4 times higher in netted
plots than control areas. The increase was
localised. Increased organic matter, percentage
fines and phaeopigment in the sediment and
reduced water flow on the netted plots is
likely to have had a major influence on the
changes in abundance of some infauna species.
Species and community effects. Netting
encouraged settlement of green macro-algae
and in turn Littorina littorea. In
the first 6 months fauna dominated by opportunistic
species P.elegans. After 1 year the stabilising
effect of netting and sedimentation led to
establishment of species such as Ampharete
acutifrons and Tubificoides benedii.
Authors consider biotic and abiotic changes
are relatively benign compared to other forms
of marine culture.
|
River
Exe |
Spencer,
B.E. et al., (1997) Ecological effects
of intertidal Manila clam cultivation: observations
at the end of the cultivation phase. J.Appl.Ecol.
34:444-452.
[PR]
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|
REF: 93
Sandbanks
Shallow inlets and bays
Estuaries
Mudflats and sandflats
|
Cockle
dredging |
Three
year study into impact and recovery of habitat
and marine benthic communities from suction
and tractor dredging to harvest cockles.
Suction dredging had a statistically significant
effect on infauna leading to up to a 30% reduction
in number of species and 50% reduction in
number of individuals. These effects were
not seen with tractor dredging. Authors suggest
this may be due to experimental design and
different times of year in which the experiments
were done. By day 56 much of the difference
between area where suction dredging was used
compared to control site was lost but some
effects remained.
|
Auchencairn
Bay, Solway Firth |
Hall,
S.J. & Harding, M.J.C. (1997) Physical disturbance
and marine benthic communities: the effects
of mechanical harvesting of cockles on non-target
benthic infauna. J.App.Ecol. 34:497-517. [PR] |
|
REF: 94
Sandbanks
Shallow inlets and bays
|
Trawling |
Simulation
in test tank of effects of otter trawl door
on infaunal bivalves when moving across a relatively
dense, level, sandy seabed. Six species of bivalve
were placed in the test bed in typical life
positions.
Habitat effects. A mound of sediment in front
of the door formed a single rounded berm with
adjacent shallow U-shaped depression which
represented the scour furrow.
Species effects. All bivalves within the
scour path at the sediment/water interface
were displaced but only 5% sustained major
damage. Shallow burrowing bivalves in the
scour path were redistributed and concentrated
along the berm. Exposure on the seabed would
make them vulnerable to predation. Increased
sediment stress was recorded to depths occupied
by deep burrowers but in this experiment the
transient elevated stress levels were considered
to be of insufficient magnitude to cause shell
damage. Possible behavioural or physiological
effects on the bivalves unknown.
|
|
Gilkinson,
K. et al., (1998) Impacts of trawl door
scouring on infaunal bivalves: results of a
physical trawl door model/dense sand interaction.
J.Exp.Mar.Biol. & Ecol. 224:291-312.
[PR]
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REF: 95
Shallow inlets and bays
Mudflats and sandflats
Estuaries
Sandbanks
Reefs
|
Various |
Review
of fishing effects on habitat. Common themes
to emerge included immediate effects on species
composition and diversity and reduction in habitat
complexity. Recovery variable depending on habitat
type, life history of component species and
natural disturbance regime.
Authors call for work to predict outcomes
of particular management regimes and discuss
use of conceptual models to do this as predictive
numerical modelling not currently possible.
Disturbance theory used to provide the framework
for predicting effects of habitat change.
Authors call for adaptive and precautionary
management practices until empirical data
become available for validating model predictions.
|
|
Auster,
P. J. & Langton, R.W. (in press).
The effects of fishing on fish habitat. Am.Fish.Soc
Symp.
[PR]
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REF: 96
Shallow inlets and bays
Mudflats and sandflats
Estuaries
|
Mariculture |
Papers
from working group meeting. Sections on fallowing
strategies in coastal cage farming and associate
research needs, minimum separation distances
between cage farming sites, on coastal management
and mariculture and on escapes. |
|
ICES
(1998) Report of the working group on environmental
interactions of mariculture. ICES CM 1998/F:2.
Ref:ACFM+ACME+E |
|
REF: 97
Shallow inlets and bays
Mudflats and sandflats
Estuaries
|
Mariculture |
Experimental
study to investigate changes in benthic communities
and sediment composition associated with clam
cultivation. Trials with four treatments, clams
with net covers, net covers only, control plots
without clams or net covers and control plats
without clams, net covers or human activity.
Sediment of the trial area was a stable muddy
sand.
Netting and the green alga growing on it
caused an increase in sedimentation rate,
and slight increase in proporation of silt.
Number of worm species increased substantially
benearth netted plots irrespective of whether
clams were present. Increase occurred within
6 months of placement and still present 2.5
years after seeding when clams were harvested.
Harvesting by hand raking, followed by suction
dredge. Suction dredge increased sediment
load in the water which dispersed to near
background levels within 40m of the device.
A trench about 10cm deep was left by the harvester
which took about 3-4 months to fill. Hand
raking caused a reduction of 50% in abundance
and diversity of species and suction dredging,
a reduction of 80-90%. Regeneration of species
diversity and abundance, after harvesting
in the winter was completed by the following
summer.
|
|
Exe
estuary
MAFF (1997) Clam cultivation:localised environmental
effects. Results of an experiment in the River
Exe, Devon (1991-95). Directorate of Fisheries
Research, Conwy.
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