ORLANDO, Fla. -- While SeaWorld's decision to end its orca breeding program has delighted animal rights activists, it has disappointed many marine scientists.

They say they will gradually lose vital opportunities to learn things that could help killer whales in the wild.

SeaWorld's 29 captive orcas in Orlando, San Diego and San Antonio will remain on display for perhaps decades to come and will be available in the meantime for study by outside scientists.

But as their numbers dwindle, researchers will lose chances to collect health data and make other observations, such as drawing blood, measuring the whales' heart rates and lung capacity, and documenting their diets and their growth.