Ontogeny of swimming behaviour in sardine Sardina pilchardus larvae and effect of larval nutritional condition on critical speed

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 504:287-300 (2014) - DOI: https://doi.org/10.3354/meps10758 Ontogeny of swimming behaviour in sardine Sardina pilchardus larvae and effect of larval nutritional condition on critical speed L. Silva1, A. M. Faria2, M. A. Teodósio3, S. Garrido4,* 1University of Algarve, Campus de Gambelas, 8000 Faro, Portugal 2Eco-Ethology Research Unit, Instituto Superior de Psicologia Aplicada, R. Jardim do Tabaco 34, 1149-041 Lisbon, Portugal 3CCMAR, University of Algarve, Campus de Gambelas, 8000 Faro, Portugal 4Centro de Oceanografia, Laboratório Marítimo da Guia, Faculdade de Ciências, Universidade de Lisboa, Avenida Nossa Senhora do Cabo, n°939, 2750-374 Cascais, Portugal *Corresponding author: garridosus@gmail.com ABSTRACT: The ontogeny of swimming behaviour in sardine Sardina pilchardus larvae was studied, from hatching to 75 days post-hatch (dph), by measuring the critical swimming speed (Ucrit) and observing locomotory behaviour. In addition, the effect of larval nutritional condition on Ucrit at the onset of their swimming abilities (20 to 25 dph) was evaluated by rearing larvae under 4 different feeding treatments. Diets consisted of different concentrations of dinoflagellates, rotifers and the copepod Acartia grani, and a wild plankton assemblage. Recently hatched larvae were mostly inactive, but from 2 dph onwards larvae started to swim freely in the rearing tank, and time spent swimming increased throughout ontogeny. Larvae younger than 20 dph (i.e. <7.90 mm TL) could not swim for the entire adjustment period at the minimum current speed, but thereafter Ucrit increased significantly with larval age and length, reaching a maximum of 9.47 cm s-1 at 19.10 mm TL and 55 dph. Growth, survival and the nutritional condition of sardine larvae, assessed by the RNA residual index, were significantly higher for larvae reared with the high-concentration diet, contrary to the other derived nucleic acids indices (RNA/DNA and DNA/DW), which showed no differences between diets. Despite differences in the survival and growth rates of sardine larvae, Ucrit at the onset of swimming did not differ significantly among diets, but was significantly related to larval nutritional condition as assessed by the RNA residual index. Overall, our results show that early larval stages of sardines have poor swimming ability and probably rely on food patches in the wild to survive; however, close to metamorphosis (especially from 45 dph onwards), larvae spend most of the time swimming and are capable of resisting the mean current speeds of their natural environment, which may strongly enhance chances for survival. KEY WORDS: Ontogeny · Critical swimming speed · Ucrit · Sardina pilchardus · Nucleic acid derived indices · RNA/DNA · Foraging Full text in pdf format PreviousNextCite this article as: Silva L, Faria AM, Teodósio MA, Garrido S (2014) Ontogeny of swimming behaviour in sardine Sardina pilchardus larvae and effect of larval nutritional condition on critical speed. Mar Ecol Prog Ser 504:287-300. https://doi.org/10.3354/meps10758 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 504. Online publication date: May 14, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.