Discussion 



Acknowledgments 



In evaluating various gear for sampling 

 juvenile blue crabs, a variety of factors should be 

 considered, such as catch effectiveness, gear cost, 

 ease of handling, and person hours. 



It generally requires two persons to efficiently 

 operate an otter trawl from a small outboard 

 motorboat. Handling an otter trawl from a small 

 outboard motorboat is not only difficult but 

 dangerous as the net can become fouled in the 

 propeller. If the net fills with mud or too much 

 debris, it is impossible to bring the gear on board 

 and the catch must be sacrificed. The push net is 

 operable by one person and snags are infrequent. 

 Mud, as well as high rooted aquatics, makes 

 pushing the net difficult. The push net is effective 

 in shallow water (Strawn 1954). Clear shallow 

 water, however, decreases the effectiveness as 

 many small crabs see the net approaching and 

 swim out of its path (pers. obs.). The crab scrape 

 can be easily handled by one person and seldom 

 becomes snagged (pers. obs. and observations of 

 commercial crabbers). 



The cost of a 3.7 m otter trawl is about $150.00. 

 The push net cost varies. They are not available 

 commercially and must be constructed, usually by 

 a local blacksmith. The bag may be cut from a 

 ripped beach seine net. The approximate cost of 

 the crab scrape is $55.00. 



Although gear cost, ease of handling, and hours 

 involved are considered in gear selection, the most 

 important factor is catch effectiveness. The push 

 net was more effective catching small blue crabs 

 than the trawl but the modified crab scrape was 

 more effective than either the push net or the 

 trawl when sampling in shallow water. 



Considering all pertinent factors, it would seem 

 that the crab scrape is the preferred gear for 

 quantitative studies of juvenile crab abundance. 



We thank Fred Dobbs and Marion Ross for their 

 valuable assistance during the field sampling, 

 Frances Younger for her technical help in the 

 preparation of the graphs, and Leo Minasian and 

 Donna L. Smawley for their photographic 

 assistance. Our thanks are also extended to Nancy 

 Robbins and Ida Marbury for their help in the 

 preparation of the manuscript. This research has 

 been supported by the National Marine Fisheries 

 Service and the State of Maryland Fisheries 

 Administration (Project No. 3-186-R-2, Contract 

 No. 04-5-043-43). 



Literature Cited 



Churchill, E. p., Jr. 



1917. Life-history of the blue crab of the Chesapeake 

 Bay. Off. Bull., Conserv. Comm. Md. 2:11-18. 

 STRAWN, K. 



1954. The pushnet, a one-man net for collecting in 

 attached vegatation. Copeia 1954:195-197. 

 SULKIN, S. D., AND R. E. MILLER. 



1975. Modified commercial crab and oyster dredges as 

 sampling devices for the blue crab Callinectes sapidus 

 Rathbun. Chesapeake Sci. 16:137-139. 

 STEVENSON, J. C, AND N. M. CONFER. 



1978. Summary of available information on Chesapeake 

 Bay submerged vegatation. U.S. Fish Wildl. Serv., Off. 

 Biol. Serv. FWS/OBS-78/66, 335 p. 



Van engel, w. a. 



1962. The blue crab and its fishery in Chesapeake Bay. 

 Part 2 - Types of gear for hard crab fishing. Commer. 

 Fish. Rev. 24(9):1-10. 



ROBERT E. Miller 



Horn Point Environmental Laboratories 

 Center for Environmental and Estuarine Studies 

 University of Maryland 

 P.O. Box 775, Cambridge, MD 21613 



DOUGLAS w. Campbell 

 Pamela J. Lunsford 



Fisheries Administration 



Maryland Department of Natural Resources 



Tawes State Office Building 



Annapolis, MD 21401 



198 



