Universidad Juárez Autónoma de Tabasco, Tabasco, Mexico. 2. CIAD A.C. Unidad Mazatlan, Mexico. 3. University of Arizona, Arizona, Tucson, USA

Transcription

1 EFFECT OF STOCKING DENSITY OF RED HYBRID TILAPIA (OREOCHROMIS SP.) ON GROWTH AND SURVIVAL OF JUVENILE TILAPIA AND SHRIMP (LITOPENAEUS VANNAMEI) IN POLYCULTURE. Alejndro Mcdonld-Ver 1,2 Neil J. Duncn 2 Wilfrido M. Contrers-Sánchez 1 Kevin Fitzsimmons 3 1 Universidd Juárez Autónom de Tbsco, Tbsco, Mexico. 2 CIAD A.C. Unidd Mztln, Mexico. 3 University of Arizon, Arizon, Tucson, USA

2 Alejndro Mcdonld-Ver who completed the study. Shrimp ponds in Mexico. Shrimp Frming Industry in Mexico. Industry is prospering. Disese nd pricing problems. Inefficient frms stop operting. Over 5 h of shrimp ponds unused. Shrimp-Tilpi polyculture. Incresed production. Mintin or improve shrimp survivl. Remove disese crriers from system.

3 Methods Pond preprtion, ploughed nd limed. Mosquito mesh divisions to mke experimentl enclosures White shrimp PL g Litopeneus vnnmei Certified free from white spot Red hybrid tilpi - 4.6±.9g Genetic component of Oreochromis mossmbicus All mles (hormonl tretment) Acclimtised to 35ppt se wter, 5ppt per dy. Pond preprtion. Slinity rnge - 28 to 35 ppt Temperture rnge to 25.6 C

4 Methods experimentl design Block C Block B Block A outlet Wter inlet. Experimentl pond set up. 9 enclosures (7x3=21m 2 ) in 3 blocks, A, B, C. All enclosures stocked with 3 shrimp/m 2 Tilpi stocked t 3 densities,,.25,.5 fish/m 2 to give the experimentl groups T, T.25 nd T.5

5 Methods Stocking. Smpling. Stocking Shrimp nd tilpi were cclimtised nd rndomly stocked into ech enclosure. Smpling. Every 2 weeks. 2 tilpi cught nd weighed. 3 shrimp weighed. Hrvest. Experiment lsted for 8 weeks. All shrimp nd tilpi were hrvested, counted nd rndom smple weighed.

6 Results - Sttistics No of obs No of obs VAR Upper Boundries (x <= boundry) 35 3 NEWVAR16 Shpiro-Wilk W=.97691, p<.2 Shrimp distribution Expected Norml Tilpi distributions 15 2 NEWVAR Shpiro-Wilk Upper W=.97111, Boundries p<.11 (x <= boundry) Expected Norml Weight dt ws not norml. Some shrimp weight distributions were highly skewed towrds lrger individuls. Some tilpi weight distributions hd chrcteristics of bimodl distribution, 23 to 42% mturing femles were found during the hrvest. 2 wy Scheirer-Ry-Hre extension of the Kruskl-Wllis nd the DUNNS test were used to compre weight distributions No of obs Survivl distributions were normlly distributed nd were compred with ANOVA Expected Norml Upper Boundries (x <= boundry)

7 Results Tilpi Growth. Weight (g) Dec 22 Dec 5 Jn 19 Jn 2 Feb No significnt differences were observed for tilpi weights mong tretments T.25 nd T.5 or blocks A, B nd C.

8 Results Shrimp Growth Weight (g) Dec 22 Dec 5 Jn 19 Jn 2 Feb No significnt differences were observed mong tretments T, T.25 nd T.5

9 Results Shrimp Growth. 3. Block A b b 2.5 Block B Weight (g) Block C b b b Dec 5 Jn 19 Jn 2 Feb Significnt differences (P<.5) were observed mong blocks A, B nd C.

10 Results Survivl. Survivl % Block A b Block Block B C T T.25 T.5 Block Block Block A B C T T.25 T.5 Shrimp Tilpi There were no significnt differences mong tilpi survivls. There were no significnt differences mong shrimp survivls for tretments, T, T.25 nd T.5. There were significnt differences (p<.5) mong shrimp survivls for blocks A, B nd C.

11 Conclusions Stocking densities of,.25 nd.5 fish/m 2 did not significntly ffect growth or survivl of juvenile shrimp nd tilpi. Block or position in the pond did significntly ffect (p<.5) growth nd survivl of juvenile shrimp. These re encourging results tht suggest shrimp tilpi poly-culture hs good potentil for diversifying the Mexicn shrimp culture industry nd rehbilitting disused shrimp ponds.

12 Grcis CRSP Jun Mnuel Gonzlez nd his fmily Gbriel Velsco Leonrdo Ibrr Rfel Guzmn Ricrdo Alvrez Michel Achury Noemi Grci Estel Rodriguez.