How serious are effects of big-game trophy hunting?

Trophy hunting, the sport that most recently claimed the life of Cecil the lion, has serious, long term effects on the species' population, warns Animal Planet's large predator expert Dave Salmoni.

"The bigger problem with trophy hunting is the fact they're always going after the biggest, the strongest, so what they're doing is removing the good genes out of the gene pool. We've actually noticed over the last 30 years, the average size of a male lion has decreased significantly," Salmoni said Monday on "CBS This Morning."

He also pointed out the immediate dangers Cecil's pride could face without their biggest protector.

"If new males do come in, they're going to kill Cecil's cubs in order to have their own," Salmoni said.

Cecil's coalition brother Jericho was believed to have been killed Saturday, but those reports proved to be false. Now, Jericho will face the difficult task of defending the pride without Cecil.

The world-famous lion's death and the killing of a second African lion have caused Zimbabwe to crack down on new hunts.

Scientists say the lion population is down more than 50 percent over 35 years. The International Union for the Conservation of Nature includes the species on its Red List of Threatened Species and in West and Central Africa, the lion is considered endangered.

Salmoni said trophy hunting is not a sustainable system and described how hunters can come to find their big-game prize.

Zimbabwe links second American to separate lion killing

"Professional hunters will say 'Come to my area, shoot this animal or that.' Often times they'll have the animal already on their property. They'll send pictures to someone and say 'Hey would you like to come kill this thing?' And they come over and have their experience," Salmoni said.

The International Fund for Animal Welfare says about 600 lions are killed legally every year on trophy hunts, and 60 percent of those animals end up in the United States.

Salmoni believes the attention Cecil's death has garnered already marks positive change and is a great representation of the world's attitude toward trophy hunting.

"If you're going to go to a certain country to have your once-in-a-lifetime safari, I think you should spend your money in places where people can't come and do these types of trophy hunts or at least the legalities are a lot more controlled," he said.

He also encouraged people interested in conservation of any animal to research organizations and determine the best way they can make a change.