Strong starvation resistance has been observed in larval decapods developing in freshwater where food appearance may be unpredictable or poor. The point-of-no-return (PNR) has often been utilized to quantify the vulnerability of a given species or developmental stage to starvation. Most studies of nutritional effects on decapods focus on marine species, while there is less information on freshwater species. We evaluated the effects of starvation on survival, growth, and hepatopancreas structure of both early (first free-living stage, JIII) and late (1 g, J1g) juveniles of Cherax quadricarinatus. The experiments consisted of treatments with increasing numbers of days without food followed by continuous feeding until Day 60 (experiment with JIII) or 90 (experiment with J1g). Regardless of body size, the time from the beginning of the experiment to first ecdysis increased with the length of the starvation period. Growth was affected by starvation in JIII, but it recovered after feeding, while growth could not be fully compensated during subsequent feeding in J1g. PNR values (means ± SD) were 8.7 ± 0.3 and 51.0 ± 1.5 d, corresponding to 125 and 220% of total stage duration, respectively. In conclusion, juvenile C. quadricarinatus are highly resistant to starvation compared to early stages of other decapods. Freshwater environments with unstable conditions of food availability may have selected for strong starvation resistance, i.e. low nutritional vulnerability. This feature gives this species potential importance for aquaculture and as an invader.
KEY WORDS: Decapoda · Parastacidae · Freshwater · Cherax quadricarinatus · Point-of-no-return · HepatopancreasResale or republication not permitted without written consent of the publisher Aquat Biol 16: 287-297, 2012 tubule consisting of different cell types, i.e. E-cell (embryonic), R-cell (resorptive), F-cell (fibrillar), and B-cell (blisterlike) (Al-Mohanna & Nott 1986Franceschini-Vicentini et al. 2009, Icely & Nott 1992. Hence, the capability of a decapod to survive transitory lack of food and to subsequently recover from such periods depends on adaptive physiological and behavioral traits and, especially, on its capacity to store energy in the hepatopancreas.All these properties vary greatly among phylogenetic groups, developmental stages, reproductive periods, and adult habitats (Sulkin & McKeen 1999, Giménez & Anger 2005, Calado et al. 2010. A particularly strong starvation resistance has been observed in larval decapods developing in freshwater, at high latitudes, or in other highly variable habitats, where food availability may be unpredictable or on average poor (e.g. Anger et al. 2004, Paschke et al. 2004. Most studies of nutritional effects on decapods, however, focus on marine species (e.g. Liddy et al. 2003, Bas et al. 2008, Zhang et al. 2009, Gebauer et al. 2010, while less have been carried out on freshwater species (Jones & Obst 2000, Anger & Hayd 2009, Powell & Watts 2010.Using larvae of the spider crab Hyas araneus as a model, Anger & Dawi...