Why does my Mac terminal show this message every time when in open?

Terminal looks in a couple of places for instructions when it starts. One of these is called .profile (note the dot), and is in the top folder of your user domain. It 's normally hidden in the Finder.

Presumably, something you installed has added a line to .profile to run that file when Terminal is launched, but the file is no longer there. User your text editor of choice to edit the .profile file, removing the relevant line.

If you don't have a preferred text editor, I Would recommend TextWrangler, which handled hidden files beautifully.

Canopy is a Python (Python is a scripting language) management tool.

If you do not need it you can delete it or reset it the company provides these directions

http://docs.enthought.com/canopy/quick-start/install_macos.html

otherwise you may download and reinstall a working copy.

https://store.enthought.com/downloads/#default

http://docs.enthought.com/canopy/quick-start/install_macos.html

While this software is not bundled with OS X or necessary for it's operation it may be installed for a specific reason to enable a user to manage Python assets, for instance you or someone who uses the computer is a Python developer.

Try this from Terminal (where $ is the prompt):

$ ls -a ~

If you see .bash_profile and/or .bash_rc in the listing,

$ rn ~/.bash_profile ~/.bash_profile-old

and/or

$ rn ~/.bash_rc ~/.bash_rc-old

Quit and re-launch Terminal. If you need/want some of your .bash_profile / .bash_rc settings/instructions, you should instead comment the line in .bash_profile or .bash_rc that is attempting to source /Users/karthy/Library/Enthought/Canopy_64bit/User/bin/activate. Add a # at the beginning of the line to comment-out the line.