ACCESSION NO: 0189294 SUBFILE: CRIS
PROJ NO: LAB93524 AGENCY: CSREES LA.B
PROJ TYPE: HATCH PROJ STATUS: EXTENDED
START: 01 JUL 2001 TERM: 30 JUN 2007 FY: 2006
INVESTIGATOR: Romaire, R. P.
PERFORMING INSTITUTION:
AQUACULTURE RESEARCH STATION
LOUISIANA STATE UNIVERSITY
BATON ROUGE, LOUISIANA 70893
DEVELOPMENT AND EVALUATION OF PRODUCTION PRACTICES TO IMPROVE PRODUCTION EFFICIENCY IN PROCAMBARID CRAWFISH AQUACULTURE
NON-TECHNICAL SUMMARY: Crawfish production in ponds is unpredictable and is impacted by climate, water quality, and production management strategies. The purpose of this study is to improve crawfish aquaculture production efficiency by identifying factors that limit reproduction and subsequent production including climatic and edaphic factors, water quality, and harvesting strategies.
OBJECTIVES: 1. Investigate the effects of climatic, physicochemical, and biological factors on reproduction, survival, growth, and subsequent yield of crawfish in ponds 2. To refine crawfish trapping strategies to reduce production cost in ponds, and initiate a new research program leading to commercial development of a formulated crawfish bait that is effective in cold water 3. Refine and validate a crawfish aquaculture computer simulation model that can assist extension personnel and crawfish producers in evaluating alternative management strategies to increase profitability.
APPROACH: The standing crop, size distribution, sex ratio, reproductive development, and condition factor of red swamp and white river crawfish adults will be determined in experimental and commercial crawfish ponds prior to late spring/early summer draining. Crawfish burrowing success and reproduction will be determined through quadrat sampling surveys of the levees and pond bottoms. The health and condition indices of reproductively active crawfish in open water and burrows will be estimated from parasitic loads on the gills, bacterial levels in the hemolymph, and moisture and lipid content of the hepatopancreas. The effects of drought on crawfish survival and reproduction will be simulated by exposing mature females, in various conditions of physiological stress, to varying levels of standing water and air moisture in artificial burrows in the laboratory. The acute and chronic effects of selected agricultural pesticides on red swamp and white river crawfishes will be conducted in the laboratory and in field mesocosm trials. Trapping and baiting strategies will be investigated to increase crawfish harvesting efficiency. Studies will focus on trap density, trap soak time, and baiting strategies, and development of a formulated bait that is effective in cold water. Eight to 12 experimental "cold water" baits will be formulated, manufactured and evaluated against fish baits and several commercially available formulated crawfish baits. Data from this project and other published research data on procambarid crawfish aquaculture will be used to refine the simulation model "CRAWPOP" which was developed to assist extension personnel and crawfish producers in evaluating alternative management strategies to increase profitability from commercial ponds.
PROGRESS: 2005/01 TO 2005/12
Effects of trap mesh size and trap density on crawfish yield and harvest size was evaluated at research stations located in south-central (SC) and southwest (SW) LA . Mean crawfish yield increased with an increase in trap density from 30 to 60 per ha (30/ha, 580 kg/ha; 45/ha, 729 kg/ha; 60/ha, 977 kg/ha) at the SC site (crawfish monocropping) but no increase in yield occurred at the SW site (rice-crawfish rotational system). Crawfish yield with 19-mm square mesh traps (819 kg/ha) was slightly higher than with 22 mm square mesh (762 kg/ha) or an equal number of 19 mm square and hex mesh traps (705 kg/ha). Although crawfish size distribution data is still being analyzed, less than 20% of harvest was estimated to be optimum market size at the SC site compared to 80% at the SW site. Size distribution and crawfish density likely account for the differences in results observed at the two research sites. Cold water crawfish baits were evaluated at water temperatures below 15 C at the SC and SW sites. At the SW site, commercially formulated and experimentally formulated baits were much less effective crawfish attractants compared to fresh fish baits. On average, fresh menhaden caught twice as many crawfish as the best formulated baits. At the SC site using the same baits, but where crawfish population densities were higher, commercially formulated crawfish baits were as effective or nearly as effective as fresh fish. The discrepancy in cold-water bait results at the two sites indicate that further cold-water bait studies are warranted. The efficacy of supplemental feeding of adult crawfish to increase survival and reproductive efficiency was evaluated. Crawfish were fed in ponds for 4 weeks prior to summer drawdown and females sequestered to artificial burrows for spawning. Crawfish spawning activity was terminated in Dec 2005 and data is being analyzed. Crawfish production area in Acadia Parish (Mermentau River Basin) southwest LA was estimated at 14,500 ha using GIS, with 94% of the area identified as double-crop rice/crawfish rotational production system. By extrapolating effluent release from overflow discharge events and final drawdown obtained from monitoring stations at three commercial crawfish farms, it is estimated that 9,000 ha-m/surface ha of effluent is discharged annually from crawfish farming operations in Acadia Parish. Crawfish production area in St. Martin Parish (Vermillion-Teche River Basin) with GIS was determined at 8,342 ha with 41% of the area identified as double-crop rice/crawfish and 29% of the area as single crop production systems. Results from water usage surveys sent to farmers in Acadia parish indicate that many producers are adopting effluent BMPs which include increasing water storage capacity, eliminating or minimizing flushing of ponds, and releasing water from final drawdown through vegetated ditches.
IMPACT: 2005/01 TO 2005/12
In 2005, crawfish were cultivated by 1,300 farmers in 53,000 ha of ponds in LA. Harvest accounts for nearly two-thirds of annual operating expenses. Trap construction materials, trap density, and cold water baits were evaluated at two sites using two different crawfish cropping schemes with the goal to improve harvesting efficiencies that would decrease production cost and increase profit. Preliminary findings indicate that trapping and bait recommendations may need to be modified for different crawfish cropping systems (monocropping vs rice-crawfish rotational systems) or adjusted to account for expected standing stocks and size distribution of harvestable crawfish. Yield on Louisiana crawfish farms is highly variable and unpredictable. A better understanding of the factors that optimize reproduction and spawning efficiency will not only help elucidate reasons for the high variability in yield observed in the crawfish farming industry but should lead to improvements in stocking practices to enable farmers to produce more predictable and stable yields. Commercial crawfish ponds in LA annually discharge effluent into impaired water basins from overflow events (precipitation and flushing for water quality improvement) and scheduled late spring/summer drawdowns. Best Management Practices (BMPs) are being identified to reduce effluent discharge and improve effluent quality from commercial crawfish operations to assist regulatory agencies in achieving total maximum daily load limits (TMDL) and generally improve water quality in southern LA drainage basins.
PUBLICATIONS (not previously reported): 2005/01 TO 2005/12
1. Parr, L. D., R. P. Romaire, and W. R. McClain. 2005. Mass loading at final drawdown in crawfish ponds. Abstracts: Aquaculture America Annual Meeting in New Orleans: 2005 January 17-20; New Orleans, Louisiana, USA. p. 312.
2. Parr, L. D., R. P. Romaire, T. M. Hymel, and W. R. McClain. 2005. Determination of Louisiana Crawfish Aquaculture Area. Abstracts: Annual Meeting of the Louisiana Chapter American Fisheries Society: 2005 February 3-4; Baton Rouge, Louisiana, USA. p. 42.
3. Romaire, R.P. 2005. Crawfish culture in forage based monocropping systems. Abstracts: Aquaculture America Annual Meeting, USA Aquaculture Society, 2005 January 17-20; New Orleans, Louisiana, USA. p. 380.
4. Romaire, R.P. 2005. Improving stream water quality in southern Louisiana by reducing the impact of crawfish aquaculture effluents through implementation of best management practices. Final Report, DEQ Contract No CFMS 575850, Louisiana Department of Environmental Quality, Baton Rouge, LA. 75 p.
5. Romaire, R.P., W.R. McClain, and M. Shirley. 2005. Live transport: crawfish. Abstracts: Aquaculture America Annual Meeting, USA Aquaculture Society, 2005 January 17-20; New Orleans, Louisiana, USA. p. 379.
6. Romaire, R.P., W.R. McClain, M. Shirley and G. Lutz. 2005. Crawfish aquaculture: marketing. SRAC Publication No. 2402, Southern Regional Aquaculture Center, Mississippi State University, Stoneville, MS. 8 p.
7. Shirley, M., R.P. Romaire, and W.R. McClain. 2005. Status and considerations for marketing crawfish in the USA. Abstracts: Aquaculture America Annual Meeting, USA Aquaculture Society, 2005 January 17-20; New Orleans, Louisiana, USA. p. 414
PROJECT CONTACT:
Name: Romaire, R. P.
Phone: 225-765-2848
Fax: 225-765-2877
Email: rromaire@agcenter.lsu.edu