Polar Biology

, Volume 36, Issue 8, pp 1195–1204

Spawning, egg development and early ontogenesis in rock cod Patagonotothen ramsayi (Regan, 1913) caught on the Patagonian Shelf and maintained in captivity

  • Alexander Arkhipkin
  • Elena Jurgens
  • Paul Nicholas Howes
Original Paper

DOI: 10.1007/s00300-013-1339-z

Cite this article as:
Arkhipkin, A., Jurgens, E. & Howes, P.N. Polar Biol (2013) 36: 1195. doi:10.1007/s00300-013-1339-z

Abstract

Rock cod Patagonotothen ramsayi (Regan, 1913) is one of the most abundant fish of the family Nototheniidae inhabiting the Patagonian Shelf and upper Slope in the southwest Atlantic. Recently, P. ramsayi became an important commercial species around the Falkland Islands with annual catch of 60,000–75,000 t. The present study aimed to reveal previously unknown aspects of reproductive biology of P. ramsayi during the first successful maintenance of adults for more than a year in an aquaculture facility with running seawater. The fish spawned at the end of austral winter. During spawning, males changed their coloration dramatically, occupied artificial shelters on the bottom and showed aggressive territorial behaviour. Egg masses were light-yellow to light-orange irregular spongiform. They were negatively buoyant, but located outside shelters and were ignored by males. Egg diameters varied between 2.1 and 2.3 mm, and the number of eggs per egg mass ranged from 26,800 to 123,400. Embryogenesis lasted 28–32 days. Total lengths of newly hatched larvae ranged from 6.2 to 6.7 mm. The yolk sac feeding period lasted approximately 11 days, during which the larvae showed negative phototaxis. One-month-old larvae attained 8.8–9.0 mm in length. This study confirms that P. ramsayi exhibit the reproductive strategy typical for nototheniid species occupying low-latitude peripheries of their distributional range, characterised by a combination of r-features (small eggs and larvae, high fecundity) and K-features (territorial behaviour and possible nest guarding).

Keywords

Patagonotothen ramsayiSpawningEgg massEmbryogenesisSouthwest Atlantic

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Alexander Arkhipkin
    • 1
  • Elena Jurgens
    • 1
  • Paul Nicholas Howes
    • 2
  1. 1.Falkland Islands Government Fisheries DepartmentStanleyFalkland Islands
  2. 2.Falklands Fish Farming Limited, The ChandleryStanleyFalkland Islands