“This one’s a virgin!” our guide Chad pronounced as he scanned the body of the 39-kg (86 pound) white sturgeon we had just pulled out of the mighty Fraser River in British Columbia. Fortunately for the fish, he wasn’t referring to sexual status, but to the fact that it had never been caught and tagged before. When I asked him to estimate the age of the massive fish, Chad said he figured it was about 50 years old. Our guide carefully examined the fish, recorded several measurements and then placed a tiny electronic PIT tag just under the skin using a special needle. Then we gently lowered the fish back…