Larval stages of Pandalus borealis

Abstract

Our studies of larval growth of Pandalus borealis revealed that the available literature for identification of the larval stages was inconsistent and thereby difficult to use. We present a robust key for identification of larval stages of P. borealis, that separates the five zoea stages (ZI–ZV), one megalopa stage (M) and the post-larva (P) in the North Atlantic. Through extensive morphometric measurements and analysis we have developed this key for the identification of larval stages that will serve as a helpful tool in future P. borealis larvae research. The key is based on the functional development of the larvae with emphasis on the telson shape, and on distinct morphological characteristics in each stage. We studied live and preserved larvae, both reared and wild caught, originating from North Norwegian fjords and the Barents Sea. The literature study suggests differences, in morphology and size, between larval stages for the Atlantic (P. borealis) and the Pacific (P. eous) species or subspecies.

Keywords:

• Development
• identification
• morphology
• Pandalus borealis
• shrimp larvae

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

The Norwegian Research Council financed this study as part of the project: ‘Larval distribution and recruitment of shrimp (Pandalus borealis, Krøyer 1838) in the Northeast Atlantic’ project no. 127469/122. We would like to thank Einar M. Nilssen at the University of Tromsø for his enthusiasm and support, and two anonymous referees for good advice. Thanks to Søren A. Pedersen and Lars Storm, Greenland/Denmark and to Patrick Ouellet, Canada, who generously shared their research data and some larvae for morphometric measurements. We are grateful to Hubert Squires for valuable information about his paper on Decapod larvae from Ungava Bay. Frøydis Strand gave us the necessary assistance when finalising the illustrations. This paper would not have been possible without the help of the crew of the R/V's ‘Ottar’, ‘Hyas’, ‘Johan Ruud’ and ‘Jan Mayen’, and the skilled staff at the Aquaculture Research Station in Tromsø and the University of Tromsø.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark