AB 16:253-264 (2012)  -  DOI: https://doi.org/10.3354/ab00457

Nutritional vulnerability of early zoea larvae of the crab Maja brachydactyla (Brachyura, Majidae)

G. Guerao1,*, C. G. Simeó1, K. Anger2, Á. Urzúa2,3, G. Rotllant

1IRTA, Unitat Operativa de Cultius Experimentals. Ctra. Poble Nou, Km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain
2Biologische Anstalt Helgoland, Meeresstation, Alfred-Wegener-Institut für Polar- und Meeresforschung, 27498 Helgoland, Germany
3Mathematisch-Naturwissenschaftliche Fakultät, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany

ABSTRACT: We investigated the nutritional vulnerability of Zoeae I of the spider crab Maja brachydactyla in experimental treatments with differential periods of starvation. As response variables, the moulting and survival rates, the point-of-reserve-saturation (PRS), the point-of-no-return (PNR), dry mass, elemental composition (carbon, hydrogen, nitrogen; CHN), hepatopancreas lipid vacuoles and activities of digestive enzymes were measured. Average median time spans when 50% of the larvae reached PNR or PRS (PNR50 and PRS50) values were 2.8 and 1.9 d, respectively. In PNR treatments, complete mortality occurred only after extended initial starvation periods of ≥5 d, and in PRS treatments, Zoeae I were capable of completing the moulting cycle after a short initial feeding period (1 d). In continuously starved control larvae, the moulting cycle was arrested at the onset of apolysis. Concomitantly, considerable amounts of biomass were lost and the C:N ratio decreased, indicating lipid degradation during starvation. This effect was also microscopically visible as a decline of lipid vacuoles in the hepatopancreas. Feeding after previous starvation periods of <7 d resulted in a re-establishment of the lipid vacuoles, indicating successful capture and ingestion of food, but this did not necessarily allow for completing the moulting cycle. In fed Zoea I larvae, digestive enzyme activities increased during the moulting cycle, while a significant decrease of enzyme activities occurred under starvation conditions. In newly moulted Zoeae II, biomass values and enzyme activities were linearly correlated with the duration of the feeding periods in Zoeae I. This study shows that biomass, elemental composition, the occurrence of lipid vacuoles in the hepatopancreas and activities of digestive enzymes are suitable indicators of the nutritional condition of early zoeal stages of M. brachydactyla.

KEY WORDS: Decapoda · Majoidea · Starvation · Point-of-no-return · Point-of-reserve-saturation · CHN · Hepatopancreas
· Condition indices

Full text in pdf format 
Cite this article as: Guerao G, Simeó CG, Anger K, Urzúa Á, Rotllant G (2012) Nutritional vulnerability of early zoea larvae of the crab Maja brachydactyla (Brachyura, Majidae). Aquat Biol 16:253-264. https://doi.org/10.3354/ab00457

Export citation
Mail this link - Contents Mailing Lists - RSS
- -