The Spot Prawn Fishery: A Status Report - Earth Economics

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The Spot Prawn Fishery: A Status Report and Management, aimed at improving the state of this type of biological and ecological knowledge. (See “Spot Prawn Stock Structure and Management” box below for details.) A pre-season test fishery has been carried out in Hood Canal since the 1970s. This research has been aimed at analyzing relative abundance and life history characteristics, such as length frequency ovigery (egg bearing), in order to set the harvest level for the coming season and determine the timing and duration of season openings. The Tulalip, Swinomish, and Suquamish Tribes also run pre-season test fisheries for ovigery to determine the percentage of female prawns that are egg-bearing. These test fisheries are carried out in the central Sound/Whidbey Basin. The Hood Canal fishery presently is a recreational and tribal commercial fishery only. The State commercial fishery has been closed since 1992. The Puget Sound (excluding Hood Canal) Pandalid Shrimp Harvest Management Plan (2001a) recognizes that biological information about Puget Sound pandalid shrimp resources is currently limited. Both parties “share the goal of collecting and analyzing additional information to improve shrimp [prawn] management” (WDFW 2001a). Additional biological information may be required in order to “make future assessments of allowable harvests and harvest methods.” This information may include the following: •develop quantitative survey methods to estimate the allowable catch by area, species, and gear type •biological basis for the establishment of harvest seasons; e.g., to deter harvest of ovigerous prawn •biological criteria for in-season data collection to evaluate harvest impacts and ensure proper resource utilization; e.g., count per pound •designation of minimum size limits of prawn and appropriate gear mesh size restrictions •designation of shrimp prawn nursery areas •identification of sub-areas needing unique management provisions •distribution and abundance of prawn species •methodology for estimation of non-commercial harvests and other fishery-related mortalities, including the bycatch of non-target species (WDFW 2001a) This additional biological information has not been collected to date. At the present time, the SPOT PRAWN STOCK STRUCTURE AND MANAGEMENT A three-year (2001, 2002, and 2003) Washington Sea Grant Program will support spot prawn research in Washington’s inshore and offshore fisheries.The need for this program arose from the fact that, despite the value of spot prawns to commercial and recreational fishing interests, little biological or ecological information is available for management. According to the Project Rationale,“The life cycle of these animals makes them especially vulnerable to overexploitation, so this information [the size, genetic structure, and relationship between the species’ various stocks] is necessary for sound management of the resource” (Lowry 2000). The Project’s primary objectives are: •“To use microsatellite DNA analysis to investigate the genetic relationships between prawns from the major fishing areas in Washington State, both inshore and offshore. •“To examine modeled and observed current and water property patterns to determine the likelihood of local retention and exchange of larvae between putative sub-populations. •“To use the above two types of information to define the ranges of the populations being fished. •“To use logbook data from the commercial fishery to determine major fishing areas offshore and develop an area-specific biomass dynamics model for use in setting maximum catches. •“To provide fishery management recommendations regarding resource sustainability, including habitat protection and the potential use of reserves as a management tool” (Lowry 2000). The Project methodology will involve sampling sites in both the offshore and inshore fisheries and comparing the genetic makeup of the animals in these two regions. Commercial fishing logbook data will be used to ensure that areas where spot prawns tend to aggregate are sampled. Genetic stock structure and distribution data will then be compared to oceanographic movement models in order to locate areas where larvae are transported, as well as where they are retained. An area-specific model of spot prawn population dynamics will be developed. This Project will allow the description of “the genetic stock structure of Washington stocks of spot prawns, within Puget Sound and the Northern Straits of San Juan de Fuca as well as offshore. Comparison of this with oceanographic features in the areas occupied by spot prawns will allow us to draw conclusions about the life history of the offshore spot prawn populations, interactions between sub-populations, and the importance of eddies to the retention of larvae in submarine canyons” (Lowry 2000). 25
The Spot Prawn Fishery: A Status Report list functions as a guide for future research plans (Cain, WDFW. Pers. comm., March 2001). History of the Fishery Washington State has had significant spot prawn fisheries since at least the 1940s. Fishing has taken place in several different areas of the State. The offshore fishery is concentrated on Washington’s outer coast in the heads of Grays, Quinalt, and Juan de Fuca canyons. The inshore fishery takes place in Hood Canal, Whidbey Island Basin, San Juan Islands, Discovery Bay, and Port Angeles Harbor. The inshore fishery includes two distinct components: a commercial tribal fishery and a state recreation fishery in Hood Canal, and a tribal and state commercial fishery in Puget Sound (excluding Hood Canal). Hood Canal and the San Juan Islands report the highest spot prawn catches. Commercial fishing activity (outside Hood Canal) is mostly centered in the eastern and central Puget Sound. Recently, commercial harvests have increased significantly, especially in the offshore fishery. Comparatively, the inshore fishery has a longer history and more stable catch trends from year to year (Lowry, University of Washington School of Fisheries. Pers. comm., May 2001). Since the 1994 Rafeedie Decision (see “The Rafeedie Decision” box), Washington State Tribes and the WDFW have shared responsibility for spot prawn management and for ensuring that harvest guidelines are allocated equitably between Tribal and non-Tribal fishers. The Northwest Indian Puget Sound (Excluding Hood Canal) Pandalid Shrimp Fishery 2001 Shrimp Pot Management Areas & Total Spot Shrimp Harvest Shares Map Courtesy Washington Department of Fish and Wildlife 26
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The Spot Prawn Fishery: A Status Report - Earth Economics

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