A net towed behind a boat for 5 to 10 minutes, sweeping fish and invertebrates from slough channels. The otter trawl is the program's workhorse — four sizes for different waterways.

The largest (OT14) has a 14-foot opening for wide channels. The smallest (OT4) fits narrow marsh creeks. A fine-mesh variant (OTL) catches larvae and tiny invertebrates that slip through standard nets.

For shallow marsh edges and mudflats where boats can't go. Two people drag a net through the shallows — a method unchanged for centuries.

Two sizes: 20 feet for tight spots, 50 feet for open shoreline. The fine mesh catches small species and juveniles that slip past larger gear.

Timing matters. Seines work best at low tide when water is shallow and fish concentrate along the margins.

Gill nets are 150 feet of mesh stretched across the current, with six panel sizes from 2 inches to 8 inches. They catch larger fish that swim through — Leopard Sharks, sturgeon, Striped Bass.

Fyke traps take a different approach: passive capture. A 3-by-6-foot frame with two 50-foot lead nets funnels fish into a holding chamber. Set and wait.

Each station's habitat determines which gear gets deployed. The monitoring design matches methods to places to build a complete picture of the estuary.

Sloughs get otter trawls — the channels are deep enough for boats and nets. Open Bay stations combine trawls with gill nets for open-water species.

Tidal pond sloughs use smaller trawls suited to restored channels. Tidal ponds get seines for their shallow, enclosed waters.