Fish and turtles

Hello, friends! Thanks to this community. Thanks to this community, I learned a lot .. I have a problem today. Periodically, fish and turtles disappear into the ocean. Altis map version 5. I can’t understand why. When you board a boat, you stop, drop the net. writes that there is no fish. Also in places of turtles there are no turtles. There are thoughts on how to solve this problem. Many thanks in advance to this community.