Look at the links below for ideas and answers. A lot of the answer depends on your current situation including the existing fish population. Standard answer is less than 10 % will live to one year in an existing pond with adult LMB population. But it depends.

http://www.pondboss.com/forums/ubbthread...=true#Post22246

http://www.pondboss.com/forums/ubbthread...=true#Post26019


See these for blocking net method. Works for BG and LMB.

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Main=5690&Number=52295#Post52295

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Main=5690&Number=52299#Post52299


See this also

http://forums.pondboss.com/ubbthreads.ph...=true#Post26019