The sentence says that local shrimpers held a news conference last week. They did so to take credit for the revival of some turtle species. In the news conference, they said something. What did they say?
Let?s focus on the part after "saying that" i.e.
- their compliance with laws requiring that turtle-excluder devices be on shrimp nets protect adult sea turtles.
Here, "requiring" is a verb-ing modifier modifying the previous noun "laws". So, "requiring that turtle-excluder devices be on shrimp nets" is a modifier modifying laws. The sentence is, therefore, essentially:
- their compliance with laws protect adult sea turtles.
We can see that we have a SV agreement error here: subject "compliance" is singular, and verb "protect" is plural.
There is no other error in the original sentence. The verb-ing modifier "requiring that turtle-excluder devices be on shrimp nets" is correct; it follows subjunctive verb format after requiring. The usage is correct.