This June data collection reservation is the first of four monthly data collection visits to assess crab activity along tidal creeks in relation to hydrological, morphological, and environmental conditions. A total of 12 transects 20m in length will be established along tidal creek banks, assigned to one of three categorized creek sections: creek head, mid-creek, and source channel. At 4 random distances along each transect, pitfall trapping and burrow counts will be conducted. Pitfall traps are made from tennis ball containers with holes drilled in the bottom for drainage. Each trap will be placed with the top of the trap flush to the marsh surface, just on the edge of the marsh plain where the creek bank ends. Plastic covers (4in. diameter) will be staked into the marsh over each trap, allowing a 1in. gap for crabs to access the trap and preventing bird chicks from falling in. One minnow trap will be baited with squid and placed in the creek at the mid-point of all transects that have a water depth of at least 5cm at the low tide of the day. All traps will be deployed for 24 hours, after which all crab individuals will be measured for carapace width, identified to species and sex, and returned live to the field. Along the top of the creek bank at the same transect locations of pitfall traps, a 0.25m x 0.25m quadrat will be used for burrow counts. The number of burrows greater than 1.5cm and burrows less than 1.5cm in diameter will be recorded. Water and air temperature will be measured with a total immersion field thermometer. Dissolved oxygen, pH, salinity, ammonia, and nitrate will be measured with a multiparameter water quality sonde at the midpoint of each transect within the channel. As a proxy for bank stability, bank angle will be measured at the same transect distances of pitfall trapping and burrow counts. Bank angle will be measured using a clinometer from the creek bed to where the creek bank meets the marsh plain.

Approved