Reproductive exhaustion in shrimp (Penaeus vannamei) reflected in larval biochemical composition, survival and growth

Penaeus vannamei larval quality in terms of biochemical composition and sur vival was studied throughout a spawning period. Spawns from broodstock at t hree different times during a commercial production period were sampled (15 , 45, and 75 days after ablation). Biochemical composition of eggs, nauplii , 15-day old postlarvae (PL15), and growth and survival during culture were determined. As the days after ablation increased, a reproductive exhaustio n of spawners was reflected in the energy reserves of the eggs produced. Ov erall larval performance during culture and survival was considerably highe r in recently ablated spawners (15 days) and decreased in spawners 45 and 7 5 days after ablation. At PL15, a test for larval resistance to a salinity stress was applied that showed a decreased PL condition related to reproduc tive exhaustion of spawners: survival to stress decreased from 89% in recen tly ablated to 68% in larvae produced 45 days after ablation, and to 39% in larvae produced to the end of the spawning period. Nauplii condition index (NCI), calculated from nauplii triacylglycerol (TG) levels, percentage of viable nauplii, and nauplii length declined in nauplii produced with spawne rs sampled 45 and 75 days after ablation. This study demonstrated that repr oductive exhaustion of shrimp spawners occurs and it becomes largely eviden t as time after ablation increases: spawner exhaustion is reflected in the quality of the larvae produced. (C) 1999 Elsevier Science B.V. All rights r eserved.