returns had been received on 

 1,603 bottles; 60.5 percent of 

 the total released. By Decem- 

 ber 1, 1957, an additional 240 

 reply cards had been returned 

 (fig. 5) giving a total return 

 of 69.5 percent--a very high 

 percentage in comparison with 

 returns in other studies 

 (table 2). The percentage re- 

 turn of bottles released during 

 any one cruise in this investi- 

 gation decreased as the season 

 progressed (table 3). 



Recoveries of bottles were 

 for the most part highest over 

 weekends (table 4). This trend 

 was especially noticeable in 

 late summer and early fall. 

 During June, July, and August, 

 the beaches and shores of the 

 lake were apparently well 

 covered throughout the week. 

 After the vacation season ended, 

 however, the shores were visited 

 more frequently on weekends. 



Table 3, — Returns of bottles released in 1956 from each of nine 

 different cruises of the Cisco and from three cruises each by 

 the Musky and Michigan Department of Conservation Patrol Boat 



[Returns from bottles recovered after February 28, 1957, 

 are not included] 



1/ Cruises during which the Musky and Michigan DeparLiiient of Conservation 

 patrol boat participated 



Recoveries before February 28, 1957, 

 were made from a point 5 miles north of 

 Sturgeon Point on the western shore of Lake 

 Huron down through Saginaw Bay, the lower 

 lake area, and up the eastern shore of Lake 

 Huron to Cape Kurd (fig. 4). Several areas, 

 however, yielded surprisingly few recovei)- 

 ies. Returns were especially light from 

 the southeasterly corner of Lake Huron 

 (fig. 4). 



Table 4.^ — Percentage distribution of recoveries of bottles 

 within the week, in the various months of recovery in 1956 



The number of returns from any pstrti- 

 cular area depends on two major factors. 

 First, of course, bottles must actually wash 

 ashore. The numbers that do are determined 

 by water moyements and shore configuration. 

 Second, the bottle must be seen and picked 

 up. Apparently all shore areas were covered 

 to some extent, especially during the vaca- 

 tion period, but the distribution of resorts 

 and beaches is by no means uniform. Conse- 

 quently, the recovery records 

 do not give a precisely accu- 

 rate measure of actual landings. 

 I believe, however, that within 

 reasonable limits they are 

 quantitatively dependable, at 

 least for central and southern 

 Lake Huron. 



Five returns made after 

 the "cut-off date" of Febru- 

 ary 28, 1957, are of particular 

 interest because the recovery 

 points were so far removed from 

 the rest. All five were re- 

 leased during the fall of 1956. 

 Apparently, travel of these 

 bottles was influenced by water 

 circulation resulting from the 

 strong southeaist, east, and 

 southwest winds that blew during 



