Open Access

Reproductive cycle and the occurrence of abnormal larvae inBranchiostoma lanceolatum at Helgoland

  • W. A. M. Courtney1
Helgoländer wissenschaftliche Meeresuntersuchungen27:BF01611685


  1. 1.

    At Helgoland (North Sea), 56% ofBranchiostoma lanceolatum develop gonads in their third year.

  2. 2.

    Spawning occurs annually through sexually dimorphic descrete areas of the gonadial envelope.

  3. 3.

    The planktonic larvae have a maximum number of 16 gill pouches and settle after 2 1/2 months.

  4. 4.

    Four of the 88 larvae taken at Helgoland in 1963 had a thick notochord and an ill-defined gut. These abnormal larvae differed from each other in structural detail.