Skimmers: their development and use in coastal Louisiana

Marine Fisheries Review, Wntr, 1995 by Stephen Hein, Paul Meier

Introduction

The development of new and more efficient methods for harvesting seafood has been a part of the Louisiana fishing industry for many years. Louisiana fishermen, as some of the Nation's leaders of seafood production, have been the source of innovative ideas for the development and improvement of fishing gear for generations. Seines, originally adopted from France and other parts of Europe, were used in the early 1800's to harvest shrimp in Lake Pontchartrain; by 1878, seines and cast nets were the primary methods of shrimp harvest (Wurzlow, 1985).

By 1915-17, availability of gasoline engines, introduction of the otter trawl, and the advent of shrimp drying led to a greatly expanded market and shrimp fishery in Louisiana (Viosca, 1957). In addition, beam trawls, plumb-staff beam trawls, bib trawls, and many variations of them were employed by fishermen throughout the years, and in certain areas some are still in use.

Boats and trawls increased in size during the 1940's, and by the 1950's double-ring trawls were adopted. In the late 1950's, twin trawls were being experimented with in Louisiana and Texas. By the early 1970's, they were becoming more efficient and popular.

Butterfly nets (wing nets or "paupiers") were introduced in the 1950's and used on stationary platforms and on shrimp boats either under power or while anchored. A butterfly net consists of square metal frame which forms the mouth of the net. Webbing is attached to the frame and tapers back to a cod end. The net can be fished from a stationary platform or a pair of nets can be attached to either side of a vessel. The vessel is then anchored in tidal current or the nets are "pushed" through the water by the vessel.

Vietnamese fishermen began moving into Louisiana in the early 1980's and introduced a gear called the "xipe" or "chopstick" net around 1983. The chopstick was attached to a rigid or flexible frame similar to the butterfly net; however, the frame mounted on the bow of the boat was attached to a pair of skids and fished by pushing the net along the bottom. As with butterfly nets, the contents of the net could be picked up and dumped without raising the entire net out of the water as is necessary with an otter trawl (Perret and Bowman, 1992). The chopstick beam trawl was designated an illegal gear for fishing in both inshore and offshore waters of Louisiana in 1984.

Development and Application

The latest gear to be developed and utilized in coastal Louisiana is the "skimmer" or "bay sweeper." This gear was developed around 1983 after much experimentation by shrimpers from the Barataria, La., area, including Will Rojas who helped pioneer the technique (Fritchey, 1989). Rojas and others who first used skimmer nets indicated that the primary reason for the development of the net was to catch the white shrimp, Penaeus setiferus, they observed jumping over the cork line as their trawls were being towed in shallow water. The skimmer net frame allows the net to be elevated above the water while the net is fishing, thus preventing shrimp from escaping over the top.

Rojas developed the idea from his son who had worked with other shrimpers using an earlier version of a similar gear used to catch shrimp in the shallow waters along the beach at Grand Isle, La. (Rojas(1)). Other fishermen report that this gear was developed from variations of the butterfly and chopstick nets; an early design consisted of trawls on frames with boards to open the net and a wheel in place of the skid (shoe) to roll along the hard sand bottom. Rojas indicated that many shrimpers were not convinced of the effectiveness of skimmer nets until some Vietnamese fishermen in Barataria, Empire, and Buras, La., successfully employed variations of his design after the chopstick nets were declared illegal. Owing to increased shrimp catch rates, less debris or bycatch, and lower fuel consumption experienced by commercial fishermen, use of skimmer nets quickly spread to other Louisiana areas.

Initially this gear was used by fishermen in Jefferson and western Plaque-mine Parishes from 1993 through 1987. Use of this gear spread west into the communities of Dulac and Theriot in Terrebonne Parish around 1988. Increased use of skimmers then moved easterly to Lafourche Parish by 1990, to eastern Plaquemine Parish around Point a la Hache by 1990-91, then to St. Bernard Parish (Fig. 1). By 1992-93 widespread adoption of skimmer nets occurred in all of these parishes in southeastern Louisiana as reflected by skimmer license sales, also licenses were sold as far north as Ouachita and Franklin Parishes (Fig. 2, 3). Recently, use of this gear has been reported from North Carolina (Hines et al., 1993).

According to Louisiana Department of Wildlife and Fisheries interviews with shrimp fishermen and wholesale shrimp dealers, skimmer nets were outcatching trawls 3:1 in western Terrebonne Parish in the fall of 1988 (unpubl. data(2)). During this period shrimp appeared more active at night and remained buried during daylight hours. Skimmer nets were easier to maneuver between the numerous crab traps, while trawlers were generally limited to only daylight hours when they could more easily avoid crab traps to prevent them from fouling in the trawls and boat propellers. Due to efficient maneuverability and the capability of following shoreline contours, as opposed to the zig-zag method employed by single rig otter trawl fishermen to keep the net out of the vessel's prop wash, skimmers are more effective in small shallow ponds. Because skimmers are pushed, rather than pulled, prop wash is not a factor.