EFFECTS OF PHOTOPERIOD MANIPULATION ON REPRODUCTIVE CYCLICITY IN HADDOCK (MELANOGRAMMUS AEGLEFINUS)

• Main Authors: D. J. Martin-robichaud, D. L. Berlinsky
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.548.6067; http://www-heb.pac.dfo-mpo.gc.ca/congress/2002/Biochem/martin-robichaud.pdf

Haddock (Melanogrammus aeglefinus) is an important, temperate, groundfish harvested commercially in the North Atlantic. As landings have declined over the last 40 years, haddock aquaculture is being developed to take advantage of high market prices and to diversify existing aquaculture operations. Haddock are group synchronous, serial spawners. Each female releases 8-10 batches of eggs spontaneously in communal spawning tanks over 4-6 weeks. For many temperate marine species, photoperiod, acting through the hypothalamic-hypophysial-gonadal axis, is the main environmental cue that influences endogenous, circannual, reproductive cycles. (Reviews: Bye, 1990; Bromage et al., 2001). For this reason, photomanipulation of reproductive cycles is routinely used to alter the spawning period of cultured fish for efficient hatchery production. The purpose of this study was to gain a basic understanding of haddock reproductive cycles and to determine the effects of photoperiod manipulation on gonadal development and circulating steroid hormone levels. Wild haddock broodstock (56-73 cm FL) were tagged and held in two 6-m tanks