mesh size and crab retention

[samiam]

Is anyone aware of research that has been done on a possible correlation between the size of square mesh in a trap (particularly a "hotel" trap or pot) and the ability of a blue crab of a certain maximum size to escape? In other words, is there a size mesh that could be used that would allow, say, >=80% of crabs that are less than 5" point-to-point to escape, and prevent the escape of >=80% of crabs over 5" point-to-point? The objective would be less culling. Obviously there are a lot of variables here. Crabs are going to "sidle" out, so if there is a "magic" mesh size it would be <5". There could be too much variation in the other dimensions (body shape) of a crab that is 5" point-to-point, especially between males and females. If bait remained in the trap, smaller crabs that could escape might not try to do so until it was too late, cancelling any culling benefit. In spite of the possible points (ha!) of failure (as well as the strong possibility that it's just a hare-brained speculation,) I've been wondering about this for a couple of years, and with the season winding down here, I thought it might be a good time to ask.

[Neither Crab]

2 x 2 in. square mesh will allow under 5in.crabs to escape. 1.5 x 1.5 is too small. You can also use 1 x 2 in. top hinged doors usually cut to 6in. x 22in. , leaving the 2 meshes on the ends of the top side of the pot for extra support and place the door over those edges and either hog ring or zip tie the door hinge. Cut out one wire to get a 2 x2 in. square in the 1 x2 in. door for small crabs to escape.

[jack1747]

A couple 2 3/8" culling rings will do the trick. Crabs less then 5" will find their way out. 

[Neither Crab]

If you are interested in cull rings , call Millers Island Crab Supply 410-477-9008 .They have the best prices by far. I'm sure they can send you some. They are mostly used in chicken wire pots in the Chesapeake Bay. Your  concern was about square mesh and not chicken wire. They are making me some 1.5 x 1.5 inch ,square mesh pots for next season and I will cut the 1x2 in. hinged door to comply with Maryland law that requires cull rings in crab pots placed in the Chesapeake Bay. Personally I don't like chicken wire because it looses its shape easily from being banged around and stacked on the boat even if braced with additional bracing wire around the crab pot frame . They catch a lot more small crabs and are more popular in the lower Chesapeake Bay where smaller crabs are more prevalent. For some reason, not many larger crabs will go into a chicken wire pot with smaller crabs. I have caught  fewer but all larger crabs in 2x2 in. square mesh pots.

[samiam]

Great info. Thanks to all!

[jack1747]

If you are interested in cull rings , call Millers Island Crab Supply 410-477-9008 .They have the best prices by far. I'm sure they can send you some. They are mostly used in chicken wire pots in the Chesapeake Bay. Your  concern was about square mesh and not chicken wire. They are making me some 1.5 x 1.5 inch ,square mesh pots for next season and I will cut the 1x2 in. hinged door to comply with Maryland law that requires cull rings in crab pots placed in the Chesapeake Bay. Personally I don't like chicken wire because it looses its shape easily from being banged around and stacked on the boat even if braced with additional bracing wire around the crab pot frame . They catch a lot more small crabs and are more popular in the lower Chesapeake Bay where smaller crabs are more prevalent. For some reason, not many larger crabs will go into a chicken wire pot with smaller crabs. I have caught  fewer but all larger crabs in 2x2 in. square mesh pots.

Don't know about MD but "all" pots in VA must have two culling rings in the polar.  Peeler pots are "not" chicken wire.  Chicken wire is galvanized wire that is woven. Peeler pot wire is galvanized after it is woven.  Easy to tell which is which, just look at the twist.  On pot wire the twist is fully galvanized. Wire pots are used more down here cause we are after the peelers. I see no difference in the size of bigger crabs caught in my peeler pots vs. hard crab pots. Course I've never seen but one 8 inch crab down here. 

[Neither Crab]

We  cut 2- 2x2s in the top release door 1x2s and it is legal in Md. You don't have to install cull rings. The DNR measured the openings from corner to corner x and we are legal. Place a cull ring over a 2x2 in. square and you can see that the square hole is slightly bigger than the cull ring hole..