Mar Biol (2011) 158:2079–2085 DOI 10.1007/s00227-011-1715-6 123 ORIGINAL PAPER EVect of unfavorable trophic scenarios on amylase and protease activity of Nephrops norvegicus (L.) larvae during their Wrst vertical migration: a laboratory approach Patricia N. Pochelon · Henrique Queiroga · Guiomar Rotllant · Antonina dos Santos · Ricardo Calado Received: 4 January 2011 / Accepted: 3 May 2011 / Published online: 21 May 2011  Springer-Verlag 2011 Abstract In Portuguese waters, Nephrops norvegicus larvae hatch at 400–800 m depth and need to perform a vertical migration to food-rich shallower waters to Wnd suitable prey. The eVect of suboptimal feeding on digestive enzymes activity of N. norvegicus larvae during this early period of their larval life remains unknown. Protease and amylase activities were investigated ex situ using Xurome- try in laboratory-hatched larvae exposed to diVerent feed- ing and/or starving scenarios in the 24 h following hatching, the period during which they typically accom- plish their upward vertical migration. Amylase activity was very low in comparison with protease activity, indicating that carbohydrates are not a primary energy reserve. Larvae starved for 12 h and subsequently fed displayed no increase in amylase activity, which suggests that feeding may be required before 12 h post-hatch to trigger amylase activity. Protease activity was high under all feeding conditions, and the increase in protease activity under sustained starvation indicated the catabolism of protein reserves. The ability of Wrst-stage N. norvegicus larvae to metabolize protein reserves may play a decisive role for their survival during their Wrst vertical migration, as it enables them to overcome the deleterious eVects of short-term starvation and/or suboptimal feeding. Introduction The Norway lobster, Nephrops norvegicus (Linnaeus 1758), is a commercially important benthic decapod crusta- cean commonly found in northeastern Atlantic waters, from the coast of Iceland to Morocco, and in the Mediterranean Sea (d’Udekem d’Acoz 1999). After embryonic incubation on the female abdomen, larvae are released from the eggs, which then develop through three zoeal planktonic stages, each intermolt period lasting about 10 days at 10°C (Figueiredo and Vilela 1972), and then migrate back to the bottom as a post-larva before settling on the benthos as a juvenile. The adult depth range varies from 15 to 800 m, although they are typically found on the NE Atlantic coast between 300 and 600 m depth (Tuck et al. 1997) and 200 and 800 m in the Mediterranean (Maynou and Sardà 1997). In addition to diVerences in the depth range, the reproduc- tion period of this species also varies with latitude, as aver- age embryo incubation period lasts up to 10 months in the northeastern Atlantic and only 6 months in the Mediterra- nean Sea (Sardà 1995). These latitudinal diVerences aVect the timing of larval hatching in N. norvegicus, with larval release occurring by early spring in the northeastern Atlantic Communicated by S. A. Poulet. P. N. Pochelon (&) · H. Queiroga · R. Calado Centro de Estudos do Ambiente e do Mar (CESAM)/ Departamento de Biologia da Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal e-mail: ppochelon@ua.pt H. Queiroga e-mail: henrique.queiroga@ua.pt R. Calado e-mail: rjcalado@hotmail.com P. N. Pochelon · A. dos Santos Instituto Nacional de Recursos Biológicos—IPIMAR, Avenida de Brasilia s/n, 1449-006 Lisbon, Portugal e-mail: antonina@ipimar.pt G. Rotllant IRTA, Ctra. Poble Nou Km 5.5, 43540 Sant Carles de la Ràpita, Tarragona, Spain e-mail: guiomar.rotllant@irta.cat