19. CADDY, J.F., "Underwater Observations on Tracks of Dredges and Trawls and 

 Some Effects of Dredging on a Scallop Ground," Journal of the Fisheries 

 Research Board of Canada, Vol. 30, No. 2, Feb. 1973, pp. 173-180. 



Three types of fishing gear tracks in bottom sediments were observed 

 from a submersible in Chaleur Bay (Gulf of St. Lawrence). Tracks from 

 past otter-trawling activities covered at least 3 percent of the bottom 

 area; these were probably made by trawl doors. Shallow tracks made by 

 inshore and offshore dredges during the course of the study could be distin- 

 guished from each other and from trawl tracks. 



Scallop dredging lifts fine sediments into suspension, buries gravel below 

 the sand surface, and overturns large rocks embedded in the sediment, thereby 

 roughening the bottom. Dredging causes appreciable lethal and sublethal damage 

 to scallops left in the track; this damage is greatest on rough bottom. 

 Incidental mortalities to scallops with an offshore dredge of at least 13 to 

 17 percent per tow are of the same magnitude as estimates of the harvesting 

 efficiency made in earlier studies. Predatory fish and crabs were attracted 

 to the dredge tracks within 1 hour of scallop dredging and were observed in 

 the tracks at densities 3 to 30 times those observed outside the tracks. 



20. CALDER, D.R., BEARDON, C.M., and BOOTHE, B.B., Jr., "Environmental Inventory 

 of a Small Neutral Embayment: Murrells Inlet, South Carolina," Technical 

 Report No. 10, South Carolina Marine Research Center, Charleston, S.C., 

 1976. 



Studies were conducted to inventory macrobenthic communities, marshlands, 

 oyster reefs, and other wetlands areas of Murrells Inlet prior to initiation 

 of a project to construct two jetties to stabilize the channel. Dredge and 

 grab samples were collected and aerial photos were used. Species diversity was 

 highest inside the inlet and lowest at the mouth of the inlet. This pattern is 

 typical of a neutral embayment and reflects the absence of a salinity gradient . 



21. CALDER, D.R., and KNOTT, D.M., "Ecological Effects of Rubble Weir-Jetty 

 Construction at Murrells Inlet, South Carolina," Interim Report, Marine 

 Resources Research Institute, South Carolina Wildlife and Marine Resources 

 Department, Charleston, S.C, Aug. 1979. 



This study at Murrells Inlet, South Carolina, describes the macrobenthic 

 communities during 1977, prior to jetty construction, and during early post- 

 construction. The effects of the north jetty construction on macroinvertebrate 

 communities were somewhat masked by seasonal population dynamics. However, 

 certain effects on the populations were apparent. The jetty construction caused 

 an increase in the number of species and altered the community structure at 

 locations sheltered by the jetty. Changes south of the jetty, which changed 

 from a high to a low wave energy environment, resulted in population changes. 

 The only other major impact during the early postconstructlon study was the 

 elimination of communities directly in the path of the jetty. However, this 

 is expected to be offset by the buildup of plants and animals on and around 

 the jetty. 



22. CALDER, D.R., et al., "A Reconnaissance of the Macrobenthic Communities, 

 Wetlands, and Shellfish Resources of Little River Inlet, North Carolina 

 and South Carolina," Technical Report No. 17, South Carolina Marine Re- 

 search Center, Charleston, S.C, 1977. 



