Reproductive cycle and the occurrence of abnormal larvae inBranchiostoma lanceolatum at Helgoland
- W. A. M. Courtney1
© Biologischen Anstalt Helgoland 1975
At Helgoland (North Sea), 56% ofBranchiostoma lanceolatum develop gonads in their third year.
Spawning occurs annually through sexually dimorphic descrete areas of the gonadial envelope.
The planktonic larvae have a maximum number of 16 gill pouches and settle after 2 1/2 months.
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.