According to Ms. Howard, why did the number of Kemp's ridley nests drop?

Ms. Howard: Today we're going to talk about the Kemp's ridley. It's the smallest sea turtle in the world, and it's also the most endangered. A full-grown adult usually weighs less than a hundred pounds.

Ms. Howard: Most Kemp's ridleys nest on one stretch of beach in northeastern Mexico, but some nest on the Texas coast, especially on Padre Island. Unlike most sea turtles, they often come out of the water to lay their eggs in the daytime, sometimes hundreds of them at once.

Ms. Howard: In the 1940s, someone filmed tens of thousands of females nesting on that beach in Mexico in a single day. By the 1980s, there were fewer than a thousand nests in an entire year. What happened? People had been collecting the eggs, and many adult turtles drowned after getting caught in shrimp nets.

Ms. Howard: So Mexico and the United States started working together. Nesting beaches were guarded, and shrimp nets were fitted with a kind of trapdoor that lets a turtle swim back out. On Padre Island, biologists began patrolling the beach to find nests and protect the eggs until they hatch.

Ms. Howard: The number of nests has gone up since then, though it still rises and falls from year to year. And if you ever see a sea turtle on a Texas beach, don't touch it. Call the number on the park signs so a biologist can come and protect the nest.