The effect of two pot types on entrance rate and entrance behavior of the invasive Japanese swimming crab Charybdis japonica

The behavior of the crab Charybdis japonica towards two pot types was recorded by camera while placed in a tank. One pot was box-shaped with two slit entrances, while the other was dome-shaped with two open funnel entrances. Pots were placed in the tank and the behaviors of single crabs were video recorded for 1.5 h (30 recordings/pot). Crabs attempting to enter the box-shaped pot had trouble getting through the entrances and 37% gave up, while 100% of those reaching the dome-shaped pot's entrances easily entered. The entrance on the dome-shaped pot was 100% efficient while that on the box-shaped pot only caught 66% of the crabs that contacted it.