Apparatus for Exclusion of Debris and by-Catch From Bottom Trawls

1. Field of the Invention

This invention relates generally to shrimp nets and apparatus associated therewith used for shrimp trawling. More specifically it discloses an attachment for various turtle exclusion devices known simply as "TEDs" or TED which are now incorporated by law into shrimp trawling nets.

2. General Background

As a result of the decimation of protected sea creatures such as the sea turtle, the National Marine Fisheries, a branch of the United States Government, now requires the use of turtle excluder devices in all shrimp trawling nets. Such devices are required to be built into all shrimp nets in a manner which allows the turtles to escape. Recently, even more pressure has been placed on the shrimping industry to also reduce the number of fin-fish (by-catch) caught in the shrimp nets. TEDs cause many problems for the shrimper, one of which is the reduction in shrimp catch. There are several factors which contribute to such losses. According to current practice, shrimp trawling nets consist of very large open mouth portions which taper progressively as they trail away from the towing vessel, narrowing to a cylindrical section known as the "cod," "bag" or "sock" end which receives the catch. Single grid hard TEDs, which are the most common in the Gulf, are usually rigid, deflector grids forming a grill work. Such TEDs usually comprise a frame having vertical bars with spacing not exceeding 4 inches, and they are generally woven or sewn into the narrow portion of the net at the mouth of the "sock" end of the net. They generally are positioned at an acute angle of between 30-50 degrees. A portion of the net in front of and above the TED is left loose as a trap door for the turtle and other large by-catch to escape as a result of contact with the TED. Openings are required to be at least 25.times.25 inches in Gulf waters. Problems occur when debris begin to accumulate on the TED and the trap door portion of the net. Debris clinging to the TED itself or to the trap door netting creates severe water turbulence which may in turn cause the trap door to remain in a partially open condition. As a result of the large opening this condition causes an out-flow of fast moving water. Such water turbulence tends to take a large percentage of shrimp out of the net preventing them from entering the "sock." Although there have been several TEDs developed which claim to reduce blockage of debris thrown up from the bottom by the net, none have proven effective because they did not address the problem of debris build up on the trap door netting as well.

As discussed above many problems exist with Turtle Exclusion Devices in present use. The primary reason being the tendency of the devices to become clogged with debris. Devices which have addressed this problem in the past overlooked the key element of how to prevent debris from being drafted into the sock or becoming entangled in the loose flap over the TED. Heretofore, it was believed that having an opening above or below the TED would simply release a considerable amount of the shrimper's catch. It has now been discovered that debris accumulation seems to be inevitable and the problem is compounded as debris build-up on the loose flap. The instant invention offers the concept that a net flap (trap door) over the TED is not necessary at all, resulting in a free flow of debris over and away form the TED, less water turbulence and more shrimp catch. The instant invention comprises a hoop and struts which may be made adaptable for most hard TEDs. The hoop is also fitted with a deflector plate to further reduce turbulence and direct a sheet of fast moving water towards the TED. This faster flowing water becomes a water curtain effectively retaining the shrimp while allowing turtles, fin-fish and the heavier, more bulky debris to pass through unrestricted. This invention is provided as a newly configured TED or may be adapted to existing HARD TEDs and is especially designed to help reduce debris build up on the TED. Therefore, effectively solving the problem of catch loss attributed to TEDs.

Since the instant invention can work effectively with almost any of the approved hard TED designs, it is an object of the invention to provide an apparatus which eliminates the need for a net flap over the TED.

It is a further object of the invention to provide an excluder device for a shrimp net which utilizes a water curtain to contain shrimp while passing fin-fish, turtles and debris in an unobstructed manner through the water curtain.

It is still a further object of the present invention to provide a hoop attachment for TEDs having the ability to stabilize and direct the water flow passing through the TED while effectively purging debris thus resisting debris build up.

For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description in conjunction with the accompanying drawings, in which, like parts are given like reference numerals, and wherein:

FIG. 1 is an isometric view of the apparatus attached to a hard TED;

FIG. 2 is a side elevation view of FIG. 1;

FIG. 3 is an isometric view of the combination shown in FIG. 1 installed in a trawl net; and

FIG. 4 is a pictorial side elevation illustration of the apparatus shown in FIG. 1 installed in a trawl net showing functionality.

FIG. 1 illustrates how the instant invention 10 comprising a hoop 12, a spoiler 14 and bracing members 16 which may be attached to a hard TED 18. Since there are many different shapes and sizes of TEDs, it should be understood that the hoop 12, its spoiler 14 and bracing 16 can be sized and shaped to meet any TED 18 configuration. However, it is essential that adequate space be provided as required by law between the spoiler 14 and the grate 20 to allow for turtles and fin-fish to escape. It is also essential that the spoiler 14 be directed in a substantially perpendicular manner towards the grate 20.

The attachment of the hoop 12 and bracing 16 may be made by any desired method of fastening including welding, mechanical clamps, tubular sockets etc.

As seen in FIG. 3 the TED 18 and the instant invention attachment 10 would be installed in its usual manner such as with the TED 18 inclined between 30 and 50 degrees with the hoop 12 forming a square or rectangular opening in the top of the net 22 essentially parallel to the flow of water through the net 22 and the TED 18 towards the cod or catch end. As seen in FIGS. 3 & 4 no net flap or mechanical trap door is required over the top of the hoop 12 and the TED 18. Therefore, turtles 24, fin-fish 26 and debris 28 can exit the net 22 by simply sliding along the grate 20 of the TED 18. Shrimp 30, which naturally move with the current, are directed through the grate 20 as a result of a portion of the stream flow being forced in a sheeting manner perpendicular to the grate 20 by the spoiler 14. Turtles 24 and fin-fish 26 have a tendency to swim towards the faster moving water created by the spoiler thereby assisting them in exiting the net 22. With no netting above the TED 18 debris 28 does not accumulate and thereby plug the grate 20. Plugging creates fast flowing streams or turbulent water which tend to confuse the turtles 24 and fin-fish 26 and further direct the shrimp catch out of the net 22.

Because many varying and different embodiments may be made within the scope of the inventive concept herein taught and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in any limiting sense.