Resumen

BALBI, Freddy et al. Acclimation to low salinity of postlarvae of marine shrimp Litopenaeus vannamei (Boone, 1931) from two commercial hatcheries. Rev. biol. mar. oceanogr. [online]. 2005, vol.40, n.2, pp.109-115. ISSN 0718-1957.  http://dx.doi.org/10.4067/S0718-19572005000200003.

Litopenaeus vannamei  postlarvae (PL₁₂ and PL₁₉) (55 PLs/L) from two commercial hatcheries (A and B), were acclimated by decreasing the salinity from 40 to 3 psu (1.5 psu/h) during a 24-h period, to evaluate survival and growth rate (total length, LT and relative growth, CR) at 24 and 72 h after acclimation. Artemia nauplii and commercial flake (32% protein) were used as food at 26-30ºC. In each treatment (triplicated) a control group (40 psu) was  maintained. Survival varied between 86 ± 7% and 98 ± 3% (control groups) and between 3 ± 2% and 93 ± 3% (acclimated PLs) and it was different (P < 0.05) between acclimated PLs and control groups at 24 and 72 h after acclimation. The highest total length was 10.3 ± 1.5 mm (PL₁₉, hatchery A) and the highest relative growth was 44 ± 4% (PL₁₂, hatchery B) both at 72 h. Total length and relative growth values did not show differences (P ≥ 0.05) between acclimated PLs and control groups at 24 and 72 h. It was concluded that L. vannamei postlarvae were successfully acclimated in brackish water of low salinity (3 psu), with similar survival and growth among PLs from hatchery A; survival rate was higher for PL₁₉ than for PL₁₂. Total length  as well as relative growth were not affected by low salinity nor by age.

Palabras clave : Crustacea; rearing; survival; growth.