Explorations were made during 8 months as 

 follows: April 1965; May 1964; June 1964 and 

 1965; July 1963; August 1963, 1964, and 1965; 

 October 1964; November 1963; and December 

 1965. In 1963, 54 drags were made during three 

 cruises; in 1964, 72 drags were made during 

 four cruises; and in 1965, 53 drags were made 

 during four cruises. 



Depth coverage by 5-fathom intervals was 

 complete for all four depth intervals in Green 

 Bay for eight cruises. Cruise 14 had no drags 

 at the 15-fathom interval, and cruises 19 and 

 24 had none at the 5-fathom interval. 



Southern Green Bay had 102 drags (48.3 

 hours), and northern Green Bay had 77 drags 

 (37.9 hours). 



SPECIES COMPOSITION OF THE 

 TRAWL CATCH 



The total trawl catch was dominated by ale- 

 wife (76.2 percent), smelt (10.7 percent), 

 suckers (5,3 percent), and carp (4.9 percent). 

 The remaining 16 species in the trawl catch 

 were only 2.9 percent of the catch by weight 

 (table 2). Only 1 percent of the catch had high- 

 value species--whitefish, yellow perch, and 

 walleye. 



The species composition differed between 

 northern and southern Green Bay, most likely 

 owing to the larger percentage of shallow water 

 drags in southern Green Bay. Greater amounts 



of warm-water species such as carp, suckers, 

 yellow perch, and spottail shiner were taken in 

 southern Green Bay whereas the percentages of 

 certain cold-water species such as sculpins, 

 common whitefish, chubs, and lake herring 

 were higher in northern Green Bay (table 3). 

 In northern Green Bay, alewife and smelt com- 

 posed over 96 percent of the catch whereas in 

 southern Green Bay, they composed 79 percent. 



DISCUSSION BY SPECIES 



Alewife 



Alewives were the most abundant fish in the 

 trawl catch; over 76 percent of the total land- 

 ings were alewives. The alewife would cer- 

 tainly be of major importance in any trawling 

 operation, and it is available in sufficient 

 quantities to support a limited trawl fishery. 



The abundance and wide distribution of ale- 

 wives in Green Bay are shown by the occur- 

 rence of alewives in all but 13 of the 179 trawl 

 drags. Of these 13 drags, 3 had damaged gear 

 or malfunctioned so that no fish were taken, 

 and the other 10 were made during cruises 17 

 and 24 (April and May), a period before the 

 alewives had moved into the bay. 



Alewives are an anadromous fish and have 

 pronounced seasonal movements. The monthly 

 catch rates and availability to bottom trawls by 

 5-fathom depth intervals are shown in figure 2. 



Table 2. --Species compositions of 179 exploratory trawl drags in Green Bay, 1963-65 



Species 



Alewife ( Alosa pseudoharengus ) 



Smelt ( Osmerus mordax ) 



Suckers ( Catostomus catostomus and C^ commersonl ) . . 



Carp ( cyprinus carplo ) 



Yellow perch ( Perca flavescens ) 



Trout-percti ( Percopsis omlscomayeus ) 



Spottail shiner ( Notropis hudsonius ) 



Common whitefish ( Coregonus clupeaformls ) 



Sculpins ( Cottidae ) 



Chubs ( Leucichthy s spp. ) 



Burbot ( Lota lota) 



Lake herring ( Leucichthys artedi) 



Yellow bullhead ( Ictalurus natalis ) 



Creek chub (Semotilus atromaeulatus ) 



Ninespine stickleback ( Pungitius pungitius ) 



Northern pike ( Esox lucius) 



Fresh-water sheepshead ( Aplodinotus grunniens ) 



Lake trout ( Salvelinus na maycush ) 



Yellowpike or walleye ( Stizostedion vitreum vitreum 

 Channel catfish ( Ictalurus punctatus ) 



Total or average 



^ T = Trace, less than 0.5 or 0.05. 



Total catch 



Pounds 



'^2,525 



5,99^1 



2,931 



2,707 



439 



3'i3 



323 



132 



132 



103 



49 



41 



15 



13 



10 



7 



4 



3 



2 



1 



55,774 



Percent""" 



76.2 

 10.7 

 5.3 

 4.9 

 0.8 

 0.6 

 0.6 

 0.2 



0.2 



99.9 



Occurrences in 

 total drags 



Number 



166 



133 



64 



26 



50 



53 



37 



31 



22 



16 



14 



18 



10 



2 



6 



4 



4 



3 



1 



1 



Percent ■'■ 



93 



74 



36 



15 



28 



32 



21 



17 



12 



9 



8 



10 



6 



1 



3 



2 



2 



2 



1 



1 



Catch 

 rate per 

 1/2 -hr. 



effort 



Pounds 



246.8 



34.8 



17.0 



15.7 



2.5 



2.0 



1.9 



.6 



.3 

 .2 

 .1 

 .1 



T 

 T 

 T 

 T 

 T 

 T 



323.6 



Average 

 catch for 

 effective 



1/2-hr. 



effort 



Pounds 



264 



47 



47 



112 



9 



6 



9 



4 



6 



6.5 



3.5 



2 



1.5 



6.5 



2 



2 



1 



1 



2 



1 



324 



