| CRD 02-01
Table
4. Impacts of Scallop Dredges on Benthic Habitat |
| TYPE OF IMPACT |
DEGREE OF IMPACT |
DURATION |
TYPE OF EVIDENCE |
COMMENTS |
| MUD |
| Removal of Major Physical Features |
N/A |
|
|
|
| Impacts to Biological Structure |
N/A |
|
|
|
| Impacts to Physical Structure |
N/A |
|
|
|
| Changes in Benthic Prey |
N/A |
|
|
|
| SAND |
| Removal of Major Physical Features |
Unknown |
|
|
|
| Impacts to Biological Structure |
XXX (L)
X (H) |
Months - Yrs |
PR, GL, PJ |
|
| Impacts to Physical Structure |
XXX (H, L) |
Days - Months |
PR, GL, PJ |
Cut (shucked) shell provides additional structure. |
| Changes in Benthic Prey |
Unknown |
|
|
Disposal of shucked scallop viscera may alter
local food sources - impacts unknown. |
| GRAVEL |
| Removal of Major Physical Features |
Unknown |
|
|
|
| Impacts to Biological Structure |
XXX (H)
N/A (L) |
Several Years (H) |
PR, GL, PJ |
(L)=deepwater banks, gravel ridges in GOM;
fishery is not prosecuted here |
| Impacts to Physical Structure |
XXX (H)
N/A (L) |
Months - Years (H) |
PR, GL, PJ |
(L)=deepwater banks, gravel ridges in GOM;
fishery is not prosecuted here. Cut shell provides additional
structure. |
| Changes in Benthic Prey |
XXX (H)
N/A (L) |
Months - Years (H) |
PR, GL, PJ |
(L)=deepwater banks, gravel ridges in GOM;
fishery is not prosecuted here |
KEY: X = Effect can be present, but is rarely
large; XX = Effect is present and moderate; XXX = Effect is often
present and can be large; N/A = Effect is not present or not
applicable; Unknown = effects are not currently known; (H) =
High energy environment; (L) = Low energy environment; PR = Peer
reviewed literature; GL = Grey literature; PJ = Professional
judgement. For definitions of Substrate Type and Type of Impact
see Appendix D.
NOTE: Ongoing Canadian experiments will be able to provide
additional information in the near future. |