Comparison of some reproductive characteristics of farmed and wild white shrimp males Litopenaeus vannamei (Decapoda : Penaeidae)

Abstract

We rated some reproductive characteristics of white shrimp Litopenaeus vannamei (Boone, 1931) males using 46 farmed individuals (weighing 21.42 +/- 0.56 g) and 40 wild individuals (weighing 36.10 +/- 0.72 g). In farmed shrimps, spermatophore mean weight was 8.94 +/- 0.51 mg

total mean sperm count was 3.90 +/- 0.27 x 10(6) in each spermatophore

and mean percentage of normal sperm was 86.9 +/- 0.37 %. In wild individuals, the respective values were 30.68 +/- 2.32 mg

6.22 +/- 1.09 x 10(6)

and 62.1 +/- 3.56 %. In both groups, the differences between right and left spermatophore were not significant (p<0.01). There were significant differences in spermatophore weight and percentage of normal sperm between farmed and wild shrimps

sperm counts differences, however, were not significant (p<0.01). The relationship between spermatophore weight (Ws) and individual weight (Wo) was Ws (mg)=1.23 (Wo)-17.34 (r(2)=0.89), in farmed shrimps

and Ws (mg)=2.57 (Wo)-60.04 (r(2)=0.64), in wild ones. In cultivated organisms, the relationship between sperm counts (Cs) and individual weight (Wo) was Cs (x 10(6))=1.1310(-4) (Wo) 3.361 (r(2)=0.85)

and versus spermatophores weight was Cs (x 10(6))=0.439 (Ws) 0.984 (r(2)=0.90). In wild organisms, there was no correlation. The proportion of normal sperm ranged from 79.8 to 95.2 % (86.9 +/- 0.37 %) and from 14.0 to 91.5 % (62.1 +/- 2.52 %), in fanned and wild shrimps, respectively. The most frequent abnormalities in both farm and wild animals were sperm without spike (49.3 % and 76.6 %, respectively) and irregular shape (35.8 % and 17.7 %). The less frequent occurrences were those of bent (10.2 % and 4.29 %) and double spike (4.7 % and 1.41 %).