Morphometric Characterization of Economically Important Populations of Black Tiger Shrimp (Penaeus monodon) Natural Broodstocks in Sri Lanka

Purpose: Presence of morphological heterogeneity and economically superior traits in naturally available brood stock greatly supports yield improvement programs characterizing sub-populations with such traits will provide leverage in doing so. The present study was an attempt to characterise giant tiger shrimp, Penaeus monodon brood stock from Sri Lankan waters to identify whether or not commercially important sub-populations exist based on morphological traits, which can be used for the yield improving P. monodon farming industry in Sri Lanka.
Research Method: A total of 495 P. monodon samples were randomly collected from nine areas around the country. Ten selected morphometric traits and the Body Weight (BW) were measured from each. Morphometric measurements were standardized and subjected to multivariate analysis with equation LTs (i)=log10LT(i)[log10 TL(m)/log10 TL(i)]b.
Findings: Selected morphological traits were highly correlated with BW showing the highest correlation from hepatic spine width and the lowest correlation by width at the midpoint of the abdominal segment six. In PCA, both PC1 and PC2 accounted for 68.1% of total variation. The scatter plot of PC1 and PC2 indicated that all samples in the nine zones belonged to one population. However, significant variations in BW, standard body length, and abdominal length were observed in different areas and the highest significant BW was recorded in Chilaw, Beruwala, Negombo, and Mullaitivu.
Originality/Value: Economically important morphological traits in Penaeus monodon are prominent in a few populations around the country, prompting to selection of individuals from these areas for brood stock improvement programs.