Bluenose,
No you can not remove the strainer. The strainer is a continuous part of the thru hull casting. If you want to get rid of the strainer you have to replace the entire thru hull fitting. I had two of them on my boat, one for the raw water intake for the motor and one for the stern tube / shaft seal cooling water supply. Changed both of them because they were blocked with barnacles.
If you decide to replace, check out Groco,s bronze fittings with BSPP threads. The threads for the thru hull fitting, ball valve ,& tailpiece all have matching threads.