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Reducing By-Catch in Crab Traps

Blue crab is one of the more popular seafood items along the northern Gulf coast; it’s certainly my favorite!  The traditional way of catching blue crab was using a simple line with meat attached to the end.  Traps made of metal and collapsing walls could be set on the bottom of the bay with bait and when a crab (or hopefully crabs J) reached the bait the fishermen could pull the trap up, closing the side panels and bring home crab cakes!  Many locals like to use what are called crab nets, which are dip-nets with an extended handle.  Fishermen would walk the shores of the bay and dip as many crabs as they could in an activity referred to as “crabbing”; I loved doing this as a kid.

The device that most know as a “crab trap” was first used in the mid-20th century.  It is basically a wire box with 2-4 openings (funnels) on the sides.  Bait is placed in a wire cylinder within the trap and the trap placed in the water near the dock or further out into the bay.  They were marked using a milk jug or cork buoy of some sort so that the fishermen would be able to find them when it was time to “check the trap”.  These were very popular.  Recreational fishermen could set a couple of traps out and watch TV or do yard work while fishing was occurring; no need to sit and watch for crabs to enter your traps.  Commercial fishermen (crabbers) could set a series of traps in several bodies of water and fish while not actually being at the location.  Today it is the primary method of crab fishing.  However the increased use of these began to put stress on the blue crab population in our state and the Florida Fish and Wildlife Conservation Commission (FWCC) began regulating the fishery.  The regulations in place today can be found at (http://www.eregulations.com/florida/fishing/saltwater/ ).  Crab traps not attached to your dock must be marked with a buoy.  This buoy should have a large letter “R”, your name and address, and be in good condition.

 

Another issue that marine biologists and fishery managers are beginning to look at is the accidental by-catch within these traps.  A variety of marine animals enter them seeking the bait or the crabs themselves.  Many of these are inedible at the time of capture and thus become discarded by-catch.  I have found toadfish, flounder, and even redfish entrapped.  An animal of particular concern is the diamondback terrapin, the only brackish water turtle in the United States.  These turtles too seek out the bait and enter the traps.  Unlike fish, turtles have lungs and are basically holding their breath when diving; obviously being caught in a crab trap while holding your breath is not going to end well.  The highest number of drowned terrapins I have personally seen in one trap is five; but there are reports of 40 terrapins in a single trap in the Chesapeake area; for them the issue is real big.

 

The primary cause of entrapment of by-catch is infrequent checking of the crab trap.  Less by-catch is found in commercial traps because they check them frequently and, if fish are in there, are released.  Recreational fishermen do not check theirs as often.  A bigger problem involves what are called “derelict” or “ghost” crab traps.  These are traps that are placed in the bay and are not checked for weeks, months, or even years. They sometimes are scattered during tropical storms and are never found by their owners. They are usually mangled and oyster encrusted.  If they are still in the water they can still catch marine life.  All of the traps I have found with drowned terrapins in them were derelict traps.

So what can we do about this problem? Well FWC developed a crab trap removal program in 2009; more about this program can be found at (http://myfwc.com/fishing/saltwater/trap-debris/).  In the program the state is divided into regions and at some time during the year each region is closed to crab fishing for 10 days; in our region that is January 5 – 15 (http://myfwc.com/fishing/saltwater/recreational/blue-crab/).  During these 10 days they sponsor a crab trap removal event and remove all crab traps not connected to docks.  The event is announced through the local media so that fishermen know to pull their traps at that time.  This program is designed to remove the derelict traps from our waters.

 

In 2012 FWC, along with other agencies such as the Florida Turtle Conservation Trust, Florida Department of Environmental Protection, the Tampa Estuary Program, and Florida Sea Grant began to produce information posters and fliers on best management practices with the use of crab traps. These practices include:

  • remove your crab trap from the water when not in use
  • check all traps at least once each day
  • use BRD’s if you are capturing diamondback terrapins; or relocate your traps to a location where terrapins are not found
  • do not place traps in channels
  • make sure you crab trap buoy is marked with a large “R”, your name and address, and that they are in good condition
  • use traps with biodegradable materials so that if lost, they will breakdown
  • you must have a recreational fishing license to fish a crab trap

 

To deal with the terrapin issue Dr. Roger Woods of the Wetlands Institute in New Jersey developed a By-Catch Reduction Device (BRD) that would keep terrapins out.  The concern was whether it would keep blue crab as well.  Dr. Woods conducted a study in the Chesapeake on different designs and their impacts on the crab fishery.  His results showed which particular design worked best and that the devices had no significant impact on the crab catch.  Actually in his study the traps using the BRD had more market sized crabs than those that did not.  The study was repeated in Florida by Dr. Joe Butler (University of North Florida) and George Heinrich (Heinrich Ecological Services) and the results were similar; no significant impacts on the crab catch.  The BRD’s are not required by the FWC but if you find that you are capturing terrapins you can get BRD’s free (while supplies last) by contacting the extension office.  I will be glad to show you how to properly place the BRD in your crab trap.  Just contact me at 850-475-5230 or roc1@ufl.edu.

 

For more information on this subject check the following resources:

 

Florida Fish and Wildlife Conservation Commission        www.MyFWC.com

FWC crab trap clean up                                     www.MyFWC.com/fishing/saltwater/trap-debris

FWC free BRD’s                                                            www.terrapin@MyFWC.com

Florida Turtle Conservation Trust                                    www.ftct.org

Diamondback Terrapin Working Group                           www.dtwg.org

Permanent link to this article: http://escambia.ifas.ufl.edu/blog/2012/08/10/reducing-by-catch-in-crab-traps/