Temperature experienced during vitellogenesis influences ovarian maturation and the timing of ovulation in common wolffish

Temperature treatment of common wolffish Anarhichas lupus during vitellogen esis affected the time of final maturation; ovulation in fish held at 8 and 12 degrees C from mid-April to October was about four and five weeks delay ed, compared with a 4 degrees C group. Fish in the 8 degrees C group had si gnificantly larger eggs than those in the 4 degrees C and the 12 degrees C groups, and a significantly higher egg production than fish in the 12 degre es C group. Temperature treatment did not affect either fertilization rate or relative fecundity, but absolute fecundity was significantly lower in th e 12 degrees C group than the other groups due to poor growth of the fish a t high temperature. This did not affect the numbers of spawning individuals . There was a trend towards lower egg survival to the eyed stage in the 12 degrees C group compared to the 4 and 8 degrees C groups, although the effe ct was not statistically significant. The results indicate that both the ti ming of final maturation and investment in ovarian growth in common wolffis h are affected by temperature experienced during vitellogenesis. (C) 1999 T he Fisheries Society of the British Isles.