Broughton Archipelago Clam Terrace Survey : final report
During a 1995 aerial video survey of the coastlineof Johnstone Strait, an unusual shoreline featurewas noted and termed “clam terraces” (inset)because of the terrace-type morphology and theapparent association with high clam productivityon the sandflats. Typical alongshore lengths of theterrace ridg...
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ftoceandocs:oai:aquadocs.org:1834/18998 2023-05-15T18:18:51+02:00 Broughton Archipelago Clam Terrace Survey : final report Harper, John R. Haggarty, James Morris, Mary C. 1995 application/pdf http://hdl.handle.net/1834/18998 en eng Coastal & Ocean Resources Inc. Sidney, B.C., Canada P95/16 http://hdl.handle.net/1834/18998 http://aquaticcommons.org/id/eprint/1129 124 2015-04-28 20:42:21 1129 Fisheries Aquaculture Canada British Columbia North Pacific Broughton Archipelago Tapes philippinarum clam culture aquaculture techniques artisanal fisheries archaeology Coastal & Ocean Resources Inc Shoreline Archeological Services Kallahin Surveying British Columbia. Land Use Coordination Office monograph 1995 ftoceandocs 2023-04-06T17:01:17Z During a 1995 aerial video survey of the coastlineof Johnstone Strait, an unusual shoreline featurewas noted and termed “clam terraces” (inset)because of the terrace-type morphology and theapparent association with high clam productivityon the sandflats. Typical alongshore lengths of theterrace ridges are 20-50m, and across-shore widthsare typically 20-40m.An area with an especially high density of clamterraces was noted in the Broughton Archipelago,between Broughton and Gilford Islands ofsoutheastern Queen Charlotte Strait. Clam terracesin this area were inventoried from the aerial videoimagery to quantify their distribution. The terraces accounted for over 14 km of shoreline and365 clam terraces were documented.A three-day field survey by a coastal geomorphologist, archeologist and marine biologist wasconducted to document the features and determine their origin. Nine clam terraces weresurveyed. The field observations confirmed that: the ridges are comprised of boulder/cobblesizedmaterial, ridge crests are typically in the range of 1-1.5m above chart datum, sandflats arecomprised almost entirely of shell fragments (barnacles and clams) and sandflats have very highshellfish production. There are an abundance of shell middens in the area (over 175) suggestingthat the shellfish associated with the terraces were an important food source of aboriginalpeoples.The origin of the ridges is unknown; they appear to be a relict feature in that they are not activelybeing modified by present-day processes. The ridges may be a relict sea-ice feature, although themechanics of ridge formation is uncertain. Sand accumulates behind the ridge because the supplyrate of the shell fragments exceeds the dispersal rate in these low energy environments.The high density areas of clam terraces correspond to high density areas of shell middens, and itis probable that the clam terraces were subjected to some degree of modification by aboriginalshellfish gatherers over the thousands of years of occupation in the region. (Document contains ... Book Sea ice IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications Canada Pacific British Columbia ENVELOPE(-125.003,-125.003,54.000,54.000) Queen Charlotte ENVELOPE(-132.088,-132.088,53.255,53.255) |
institution |
Open Polar |
collection |
IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications |
op_collection_id |
ftoceandocs |
language |
English |
topic |
Fisheries Aquaculture Canada British Columbia North Pacific Broughton Archipelago Tapes philippinarum clam culture aquaculture techniques artisanal fisheries archaeology Coastal & Ocean Resources Inc Shoreline Archeological Services Kallahin Surveying British Columbia. Land Use Coordination Office |
spellingShingle |
Fisheries Aquaculture Canada British Columbia North Pacific Broughton Archipelago Tapes philippinarum clam culture aquaculture techniques artisanal fisheries archaeology Coastal & Ocean Resources Inc Shoreline Archeological Services Kallahin Surveying British Columbia. Land Use Coordination Office Harper, John R. Haggarty, James Morris, Mary C. Broughton Archipelago Clam Terrace Survey : final report |
topic_facet |
Fisheries Aquaculture Canada British Columbia North Pacific Broughton Archipelago Tapes philippinarum clam culture aquaculture techniques artisanal fisheries archaeology Coastal & Ocean Resources Inc Shoreline Archeological Services Kallahin Surveying British Columbia. Land Use Coordination Office |
description |
During a 1995 aerial video survey of the coastlineof Johnstone Strait, an unusual shoreline featurewas noted and termed “clam terraces” (inset)because of the terrace-type morphology and theapparent association with high clam productivityon the sandflats. Typical alongshore lengths of theterrace ridges are 20-50m, and across-shore widthsare typically 20-40m.An area with an especially high density of clamterraces was noted in the Broughton Archipelago,between Broughton and Gilford Islands ofsoutheastern Queen Charlotte Strait. Clam terracesin this area were inventoried from the aerial videoimagery to quantify their distribution. The terraces accounted for over 14 km of shoreline and365 clam terraces were documented.A three-day field survey by a coastal geomorphologist, archeologist and marine biologist wasconducted to document the features and determine their origin. Nine clam terraces weresurveyed. The field observations confirmed that: the ridges are comprised of boulder/cobblesizedmaterial, ridge crests are typically in the range of 1-1.5m above chart datum, sandflats arecomprised almost entirely of shell fragments (barnacles and clams) and sandflats have very highshellfish production. There are an abundance of shell middens in the area (over 175) suggestingthat the shellfish associated with the terraces were an important food source of aboriginalpeoples.The origin of the ridges is unknown; they appear to be a relict feature in that they are not activelybeing modified by present-day processes. The ridges may be a relict sea-ice feature, although themechanics of ridge formation is uncertain. Sand accumulates behind the ridge because the supplyrate of the shell fragments exceeds the dispersal rate in these low energy environments.The high density areas of clam terraces correspond to high density areas of shell middens, and itis probable that the clam terraces were subjected to some degree of modification by aboriginalshellfish gatherers over the thousands of years of occupation in the region. (Document contains ... |
format |
Book |
author |
Harper, John R. Haggarty, James Morris, Mary C. |
author_facet |
Harper, John R. Haggarty, James Morris, Mary C. |
author_sort |
Harper, John R. |
title |
Broughton Archipelago Clam Terrace Survey : final report |
title_short |
Broughton Archipelago Clam Terrace Survey : final report |
title_full |
Broughton Archipelago Clam Terrace Survey : final report |
title_fullStr |
Broughton Archipelago Clam Terrace Survey : final report |
title_full_unstemmed |
Broughton Archipelago Clam Terrace Survey : final report |
title_sort |
broughton archipelago clam terrace survey : final report |
publisher |
Coastal & Ocean Resources Inc. |
publishDate |
1995 |
url |
http://hdl.handle.net/1834/18998 |
long_lat |
ENVELOPE(-125.003,-125.003,54.000,54.000) ENVELOPE(-132.088,-132.088,53.255,53.255) |
geographic |
Canada Pacific British Columbia Queen Charlotte |
geographic_facet |
Canada Pacific British Columbia Queen Charlotte |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
http://aquaticcommons.org/id/eprint/1129 124 2015-04-28 20:42:21 1129 |
op_relation |
P95/16 http://hdl.handle.net/1834/18998 |
_version_ |
1766195589285937152 |