Analysis of sea turtle bycatch in the commercial shrimp fisheries of Southeast U.S. waters and the Gulf of Mexico

The coastal shrimp trawl fisheries have long been the focus of conservation actions to reduce turtle bycatch and mortality in the Gulf of Mexico and the U.S. Atlantic (NRC, 1990). Calculation of catch rates of sea turtles in shrimp trawls is necessary to evaluate the impact on sea turtle populations. In this paper we analyze sea turtle bycatch to provide an estimate of the current number of interactions with otter trawl gear as well as an estimate of the number of fatal inions in Southeast U.S. waters and the Gulf of Mexico. We also provide an estimate of the number of individuals likely to die in the future with the new regulations that will require an increase in the size of the escape openings in trutle excluder devices (TEDs). The new regulations will allow many more turtles to escape. Other gears also are discussed. (PDF contains 24 pages)

Assessment of the fishing effort level in the shrimp fisheries of the central and southern Gulf of California

In view of the concern caused by the declining trend in the annual shrimp yield in the Central Gulf of California, an attempt was made to analyze the fishing effort level exerted upon the shrimp stocks of the blue (Farfantepenaeus stylirostris) and the brown shrimp (F. californiensis) from 1980 to 1991. For this purpose, both Schaefer and Fox production models were applied. The results from these analyses revealed an economic overexploitation condition, and suggested an imperative need to implement as a regulatory measure, the reduction of the catch per unit of effort level (CPUE) to keep the fishery within acceptable bioeconomic margins of a maximum sustainable yield (Ys). This can only be achieved through the adjustment of the fleet size from 481 vessels down to 250 or 275.

The Lobster and Shrimp Fisheries in Hawaii

A description of the lobster and deepwater shrimp fisheries in Hawaii, addressing harvest levels, biology, and research, is presented. Both fisheries are trap fisheries. The lobster fishery is a limited entry fishery with 1991 landings of 200 metric tons. The shrimp fishery is unregulated, with very sporadic effort, and annual landings below 200 metric tons.

A Demographic Profile of Participants in Two Gulf of Mexico Inshore Shrimp Fisheries and Their Response to the Texas Closure

A social study of the shrimp fisheries of Galveston Bay, Tex., and Calcasieu Lake, La., was made during the summer of 1987 to examine the impacts of the seasonal closure of the Federal waters off Texas and to understand the infrastructure and demographic processes of these two diverse fisheries. Survey instruments were administered to 159 shrimp boat captains: 89 from Galveston Bay and 70 from Calcasieu Lake. Shrimp-house owners were interviewed in each region as well. The results suggest that the inshore fisheries (i.e., shrimpers and shrimp houses) are distinct from the offshore fisheries. The infrastructure of the two inshore fisheries examined differ in that the market distribution of shrimp from Galveston Bay was more diffuse than from Calcasieu Lake. Much more of the shrimp harvested from Galveston Bay was channelled into the surrounding community than from Calcasieu Lake. The distribution of age,years as a commercial fisherman, and family involvement in fishing suggest that participation in Calcasieu Lake's and Galveston Bay's inshore fisheries have expanded concurrent with declining economies. While overall the Texas closure had little impact on either of the inshore fisheries, the Galveston Bay shrimpers experienced more of a direct impact on their livelihood than Calcasieu Lake shrimpers.

Characterization of the U.S. Gulf of Mexico and South Atlantic penaeid and rock shrimp fisheries based on observer data

In July 2007, a mandatory Federal observer program was implemented to characterize the U.S. Gulf of Mexico penaeid shrimp (Farfantepenaeus aztecus, F. duorarum, and Litopenaeus setiferus) fishery. In June 2008, the program expanded to include the South Atlantic penaeid and rock shrimp, Sicyonia spp., fisheries. Data collected from 10,206 tows during 5,197 sea days of observations were analyzed by geographical area and target species. The majority of tows (~70%) sampled were off the coasts of Texas and Louisiana. Based on total hours towed, the highest concentrated effort occurred off South Texas and southwestern Florida. Gear information, such as net characteristics, bycatch reduction devices, and turtle excluder devices were fairly consistent among areas and target species. By species categories, finfish comprised the majority (≥57%) of the catch composition in the Gulf of Mexico and South Atlantic penaeid shrimp fisheries, while in the South Atlantic rock shrimp fishery the largest component (41%) was rock shrimp. Bycatch to shrimp ratios were lower than reported in previous studies for the Gulf of Mexico penaeid shrimp fishery. These decreased ratios may be attributed to several factors, notably decreased shrimp effort and higher shrimp catch per unit of effort (CPUE) in recent years. CPUE density surface plots for several species of interest illustrated spatial differences in distribution. Hot Spot Analyses for shrimp (penaeid and rock) and bycatch species identified areas with significant clustering of high or low CPUE values. Spatial and temporal distribution of protected species interactions were documented.

Informational report: Bycatch reduction devices used in the Pink Shrimp trawl fishery

The California Fish and Game Commission (Commission) has the authority to require one or any combination of Bycatch Reduction Device (BRD) types in the trawl fishery within California waters for Pacific ocean shrimp (Pandalus jordani), most commonly referred to as pink shrimp. The purpose of this report is to provide the Commission with the best available information about the BRDs used in the pink shrimp trawl fishery. The mandatory requirement for BRDs occurred in California in 2002, and in Oregon and Washington in 2003, resulting from an effort to minimize bycatch of overfished and quota managed groundfish species. Three types of BRDs currently satisfy the requirement for this device in the California fishery: 1) the Nordmøre grate (rigid-grate excluder); 2) soft-panel excluder; and 3) fisheye excluder; however, the design, specifications, and efficacy differ by BRD type. Although no data has been collected on BRDs directly from the California pink shrimp fishery, extensive research on the efficacy and differences among BRD types has been conducted by the Oregon Department of Fish and Wildlife (ODFW) since the mid-1990s. Rigid-grate excluders are widely considered to be the most effective of the three BRD types at reducing groundfish bycatch. Over 90 percent of the Oregon pink shrimp fleet use rigid-grate excluders. The majority of the current California pink shrimp fleet also uses rigid-grate excluders, according to a telephone survey conducted by the California Department of Fish and Game (Department) in 2007-2008 of pink shrimp fishermen who have been active in the California fishery in recent years. Hinged rigid-grate excluders have been developed in recent years to reduce the bending of the BRD on vessels that employ net reels to stow and deploy their trawl nets, and they have been used successfully on both single- and double-rig vessels in Oregon. Soft-panel excluders have been demonstrated to be effective at reducing groundfish bycatch, although excessive shrimp loss and other problems have also been associated with this design. Fisheye excluders have been used in the California fishery in the past, but they were disapproved in Oregon and Washington in 2003 because they were found to be less effective at reducing groundfish bycatch than other designs. The reputation of the United States west coast pink shrimp fishery as one of the cleanest shrimp fisheries in the world is largely attributed to the effectiveness of BRDs at reducing groundfish bycatch. Nevertheless, BRD research and development is still a relatively new field and additional modifications and methods may further reduce bycatch rates in the pink shrimp fishery.(PDF contains 12 pages.)

Technical and economic viability of traps in the portuguese fishery of deepwater rose shrimp (Parapenaeus longirostris)

Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

The relationship between environmental variation and species abundance in shrimp community (Crustacea : Decapoda : Penaeoidea) in south-eastern Brazil

The impact of shrimp fisheries in tropical regions has become comparable to the world's most intensively exploited temperate shed ecosystems. The increase in the fishing fleet in south-eastern Brazil and the decrease in landings of profitable shrimp species have contributed to the incorporation of additional species into those fisheries. The goal of the present study is to investigate the influence of environmental factors on the abundance patterns of shrimp communities on the south-eastern coast of Brazil, over a period of two years. Monthly collections were conducted in the Ubatuba and Caraguatatuba regions using a commercial shrimp fishing boat equipped with 'double-rig' nets. Each region was divided into 7 sampling stations up to 35 m deep. The relationship between the environmental factors and the abundance patterns in the shrimp communities was assessed using a canonical correlation analysis (CCorrA). The first set of variables used during the CCorrA included environmental characteristics and the second set of variables the abundance of the studied species. A total of 374,915 individuals were collected during the present study. Xiphopenaeus kroyeri showed the highest abundance (273,127), followed by Artemesia longinaris (73,422), and Pleoticus muelleri (15,262). In the first root, depth and temperature showed the highest factor loadings (0.9 and -0.7) and canonical weights (0.6 and -0.4). These environmental factors were strongly associated with the abundance of X. kroyeri (factor loading = - 0.9 and canonical weight = - 0.9). The second root demonstrated a positive relationship between abundance of P. muelleri and depth, and an inverse association with bottom temperature. The abundance patterns of X. kroyeri and P. muelleri were strongly affected by the water mass South Atlantic Central Water (cold waters =15 degrees C), which can lead to a temperature decrease in deeper areas (> 15 m). Thus, the opposite abundance trend for depth of these species might reflect bathymetric variation in temperature, a clear example of distinct behavioural differences of species of different origins, either tropical (X. kroyeri) or subantarctic (P. muelleri). The low overall association between environmental parameters and shrimp abundance patterns indicates that each studied species might have responded idiosyncratically to environmental variation, such that a general community-level response was not apparent. However, other confounding factors such as intraspecific migration patterns might have also played a role in generating the observed patterns.

Diel Variation in Abundance and Size of the South American Red Shrimp Pleoticus Muelleri (Spence Bate, 1888) (Decapoda, Solenoceridae) in the Ubatuba Region, Southeastern Brazil

Diel variation in the abundance and size of Pleoticus muelleri in the Ubatuba region was investigated during 2000. During each season of the year, sampling was conducted during the day and at night at 8 depths, from 5 to 40 m. The estimated number of shrimp was 955 individuals, 272 collected during the day and 683 at night. There was a difference in the abundance of P. muelleri between day and night (χ², p=2.33E-40). The abundance during the day and at night differed by season with the exception of the spring (χ², p=0.06). The abundance during both periods also differed by depth, except at 15 and 30 m, where it was not significant (χ², p=0.84 and 0.06, respectively). The shrimp caught at night were generally smaller than those caught during the day (Kolmogorov-Smirnov, p<0.01). Pleoticus muelleri juveniles were found primarily at night. This tendency could have influenced the lower mean size for this period. The sediment type and the bottom temperature appear to influence the behavior of this species and consequently the catch rate during the periods analyzed.

STREAM Journal, Vol. 5, No. 4, pp 1-18. October-December 2006

CONTENTS: Success story of one-stop aqua shop in Kaipara Village, by Kuddus Ansary. Enhancement of people’s livelihoods in Kompong Kra Sang community fishery, by Chun Sophat. Char livelihoods of the old Brahmaputra River in Bangladesh, by Nesar Ahmed. Fin fish community structure as a measure of ecological degradation in two tropical rivers of India, by D. Chakrabarty and S.K. Das. Penaeid shrimp fisheries of Pakistan, by Razia Sultana. Reviving the shrimp industry in Capiz, by Jessica C. Esmao.

Die Fangmengen an Nordseegarnelen und fischereilicher Aufwand im europäischen Vergleich - Langzeitserien und saisonale Übersicht

Among other tasks the “Working Group on Crangon Fisheries and Life Cycle” of the “International Council for the Exploration of the Sea” collects data on landings and effort in the North Sea brown shrimp fisheries by country. Landings per unit effort data are calculated and all are compared on basis of long-term series as well as on seasonal basis. The development for each country is described and compared for the year 2001 to the ten-year average from 1992 to 2001 were possible, as some data are missing especially for the Netherlands. While the Dutch and British fleets increased their landings substantially in 2001 compared to the previous years, Danish,German and Belgian fishermen had reduced landings. There are regional differences in fishing pattern between the countries, especially Denmark versus the rest of Europe. Effort measures remain incomparable between the countries, and fluctuations in landings per unit effort data seem to be in a normal biological range, giving no reason for concern at present for the situation of brown shrimp stocks in the North Sea. An improvement of the data basis is required and possibly achievable by the EU logbook system being in force for brown shrimp fisheries as well.

Fischereilich-ökonomische Überlegungen zu Chancen und Risiken in der Garnelenfischerei - am Beispiel des Schollendiscards (Ein Thesenpapier auf der Basis von EU-Studien und Langzeitreihen)

Though economic research is not one of the tasks of the German Federal Research Centre for Fisheries, basic in-formation for such work is available from biologic studies on fish biomass, discards and seasonal abundance of species. Results from EU-studies on brown shrimp fisheries show the effect of discarding juvenile fish, especially plaice, the possibly lost numbers and value of this fish as well as chances of reducing these losses by a timely effort reduction in summer and the use of selective nets throughout most parts of the year. However, it is also made clear, that these costly measures may have no effect on the stocks due to biological compensatory effects observed in strong year classes of plaice e. g. 1996, with high landings and collapsing prices. Therefore sound biological and economic data and methods are needed to assess the economic effects of management measures on fishermen’s situation and markets. Compensations for catch limitations may become inevitable.