Negombo lagoon estuarine prawn fishery: stake-net (Ja-Kottu) barrier positioning and tides?

The Ja-Kottu (stake-net barrier) fishery is an intensive traditional fishing method operating across the tidal channels of Negombo Lagoon. Fishers drive rows of mangrove and bamboo stakes into the lagoon bed to form a massive V-shaped barrier fence. At the apex of the V, a conical net trap (Kotu Dela) is secured. During outgoing nocturnal low tides, ebbing brackish water flushes shrimp and prawns down the estuary currents, guiding them straight into the funnel trap. Fishers check traps at midnight and dawn, sorting jumbo tiger prawns and crabs by size.