The physiological consequences of delaying metamorphosis in the marine ornamental shrimp Lysmata seticaudata and its implications for aquaculture
Abstract The timing of metamorphosis has recently been referred as a more suitable proxy to evaluate postlarval quality than size. Indeed, while displaying a larger size at settlement, late settlers that originate from larvae that have delayed metamorphosis commonly display poorer growth performances This delay in metamorphosis is possibly at the expenses of larval endogenous energetic reserves that, once allocated to facilitate the delayed transition to benthic life, will no longer be available to help fuelling early juvenile somatic growth. To further advance our knowledge on this topic, we evaluated the physiological status (energy reserves and allocation, aerobic and anaerobic energy consumption), along with biochemical responses related with detoxification processes, antioxidant defences, oxidative damage, neuromotor activity in early settlers (ES), middle settlers (MS) and late settlers (LS) of postlarvae of the marine ornamental shrimp Lysmata seticaudata. Our results revealed that LS postlarvae presented a higher weight compared to MS and ES, likely related with a lower metabolism and neuromotor activity. Yet, the low metabolism allied with diminished detoxification and antioxidant capacities seemed to result in an increased oxidative stress condition that may negatively condition the growth performance of LS postlarvae. Conversely, ES postlarvae presented a lower weight, likely because of high metabolic costs associated with increased neuromotor activity, detoxification, and antioxidant capacities to avoid oxidative damage. The present study highlights how the physiological, metabolic and biochemical status of L. seticaudata postlarvae is shaped by the timing of their metamorphosis, as well as how this event will shape their early benthic life and confirms that a larger size or weight at metamorphosis may not be good proxies to select premium seedlings for grow-out. Overall, metamorphosis is not a new beginning and does not reset larval history. Crustacean farmers should avoid decoupling larviculture history from grow-out, as only by knowing larval performance to metamorphosis will it be possible to enhance survival and growth performances to commercial size.