stratum catch cells 0-2m 0 172 0-2m 2 172 0-2m 2 172 0-2m 2 172 0-2m 3 172 0-2m 1 172 0-2m 3 172 0-2m 2 172 0-2m 2 172 0-2m 0 172 2-4m 4 80 2-4m 2 80 2-4m 3 80 2-4m 5 80 2-4m 2 80 2-4m 4 80 2-4m 1 80 2-4m 3 80 2-4m 2 80 2-4m 3 80 >4m 7 68 >4m 5 68 >4m 7 68 >4m 7 68 >4m 5 68 >4m 5 68 >4m 7 68 >4m 6 68 >4m 3 68 >4m 5 68