Bottom Trawl Explorations in Green Bay of 

 Lake Michigan, 1963-65 



by 



NORMAN J. REIGLE, JR., Fishery Biologist 



Bureau of Connmercial Fisheries 



Exploratory Fishing and Gear Research Base 



Ann Arbor, Mich. 48103 



ABSTRACT 



A bottom trawling survey was made during 11 cruises operating for 36 days 

 over the 3-year study period. Explorations were made at all possible fishing depths 

 and during 8 months. The 179 exploratory drags made during this study represent the 

 first attempts by the Bureau of Connmercial Fisheries to determine if bottom trawl- 

 ing in Green Bay is commercially feasible. 



The overall catch rate was at a level that would be commercially feasible for a 

 trawl fishery based primarily on alewife ( Alosa pseudoharengus ) and smelt ( Osmerus 

 nnordax ) and supplemented by catches of suckers ( Catostomus catostomus and C^. 

 commersoni ), carp (Cyprinus carpio ), and yellow perch ( Perca flavescens ). Game 

 fish were taken infrequently in the trawl, and trawling would not jeopardize sport 

 fishing in Green Bay. 



INTRODUCTION 



The commercial fishery in Green Bay was 

 a gill net and pound net fishery based on three 

 primary species: common whitefish ( Coregonus 

 clupeaformis ), lake herring ( Leucichthys 

 artedi ), and yellow pike or walleye ( Stizostedion 

 vitreum vitreum ) and five secondary species: 

 carp, lake trout ( Salvelinus namaycush ), smelt, 

 suckers, and yellow perch. Landings of the 

 three major species have declined markedly 

 in recent years. Of the secondary species, the 

 lake trout almost disappreared from Lake 

 Michigan (Eschmeyer, 1957); however restock- 

 ing efforts are nowunderway. A limited fishery 

 for carp, smelt, suckers, and yellow perch 

 still exists in Green Bay. Hile, Lunger, and 

 Buettner (1953) have summarized the fishery, 

 and discussions of the major species in Green 

 Bay have been presented for the whitefish by 

 Mraz (1964), for the lake herring by Smith 

 (1956), and for the walleye by Hile (1955) and 

 Pycha (1961). 



If connmercial fishing in Green Bay is to 

 survive, fishermen will have to turn to the 

 efficient harvest of large volumes of low- 

 priced industrial fish. Trawling is one way to 

 accomplish this goal. 



The ainn of the study was to obtain the basic 

 seasonal and bathynnetric data necessary to 



establish more effective and efficient fishing 

 nnethods to harvest the existing fish re- 

 sources. 



VESSELS, GEAR, AND METHODS 



All fishing explorations during this study 

 were nnade by research vessels of the Bureau 

 of Commercial Fisheries. The research vessel 

 Cisco was used on two cruises (lZand30), and 

 the research vessel Kahoonthe remaining nine 

 cruises. 



All trawling was done with a 52-foot (head- 

 rope) Gulf of Mexico type fish trawl (Gordon 

 and Brouillard, 1960). The cod end of the net 

 had a 1-inch mesh (stretch measure) cotton 

 liner to retain young fish and smaller species. 

 A "white line" echo sounder was used during 

 the trawling to observe and record fish con- 

 centrations. 



Most trawl drags were 1/2-hour long al- 

 though one was extended to 80 minutes, and 

 15 were less than one-half hour for one of the 

 following reasons: encounters with snags, 

 rough bottom, or stationary fishing gear (gill 

 nets or pound nets). Most of Green Bay is 

 suitable for bottom trawling, and snags were 

 generally encountered close to shore (fig. 1). 

 Gear was dannaged severely on four drags and 

 had minor damage on five drags. 



