I wonder if there is a fish processing workshop/fish market/jetty somewhere to attract the sea galls.

Or it is the spawning whitebaits or "sardines" that are expected in the Gulf of Thailand about this time of year (March). I hope it is the spawning fish.

Samutprakarn is where they want to deepen the Port's water channel.

Dredging or digging and stirring up mud at spawning time could mean loss of fish breeding grounds

and of course less or no fish (especially ปลาทู and ปลาทำน้ำปลา) for the people who depend on fishing.

What we see now may be the beginning of our future ;-)