Manipulation of Reproductive Function in Atlantic Salmon (Salmo salar) Kelts with Controlled Photoperiod and Temperature

Abstract

Atlantic salmon (Salmo salar) kelts exposed to a regime of two 6-mo seasonally accelerated light increases and decreases (2CP) in 1989 spawned in the spring of 1990 when water temperatures were above 7 °C during the winter months. Kelts exposed to water temperatures below 4 °C during the same period failed to spawn in the spring. Exposure of the nonspawning 2CP kelts to warmer water temperatures in the summer of 1990 stimulated egg development and ovulation by 17 October 1990. Kelts exposed to a simulated natural 12-mo photoperiod regime also spawned at this time. Eggs and sperm from kelts spawned in the spring were viable. Spring-spawned eggs fertilized with fresh sperm had lower survival levels to the eyed-egg stage or to hatch than did eggs from wild fall-spawned stocks. Kelts entrained to spawn in the spring with 2CP photocycles were manipulated to spawn again in the spring of the next year following exposure to a time-shifted photoperiod and elevated winter/spring water temperature.

Growth in adult gilthead sea bream (Sparus aurata L) as a result of interference in sexual maturation by different photoperiod regimes

“…However, inestigation of this has led to contradictory conclusions. Whereas some authors concluded that it is necessary to have short days after the stimulus of long days (Elliot, Bromage & Springate 1984; Johnston, Hambrook, Gray & Davidson 1992), in other cases this only has a beneficial effect on the advancement of sexual maturation (Kadmon et al . 1984, 1985a; Pavlidis et al .…”

Changes in alkaline phosphatase isoenzyme activity in tissues and plasma of Atlantic salmon (Salmo salar) before and during smoltification and gonadal maturation

“…Vitellogenin is a large phospholipoprotein extruded from hepatocytes to the extracellular fluids through the process of exocytosis. During September and October when vitellogenin synthesis peaks and oocyte size doubles, there is a dramatic increase in liver, ALP isoenzymes in the plasma (Wallace 1985;Johnston et al 1990Johnston et al , 1992Crim et al 1992). Cellular breakdown with plasma membrane discharge of ALP isoenzymes or increased activity in the plasma of phospholipase D are the most probably causes for this rise in plasma activity (Moss 1992).…”

“…The strong correlation between oocyte development and plasma ALP activity suggested that ALP activity might be associated with thyroid hormone level changes and estradiol driven hepatic vitellogenesis (Eales et al 1991;Johnston et al 1992;Crim et al 1992). Since few ALP studies have been undertaken on fish, a more definitive explanation of the changes in ALP isoenzymes or their functional roles should be developed.…”

The importance of parentage in assessing temperature effects on fish early life history: a review of the experimental literature

“…This included examining temperature effects in relation to photothermal conditioning protocols for producing offspring out of season (Morrison and Smith 1986;Johnston et al 1992;Davies and Bromage 2002;Clark et al 2005;Van der Meeren and Ivannikov 2006), concerns for broodstocks at facilities in geographical locations with elevated ambient thermal profiles (Pankhurst et al 1996;Webb et al 1999Webb et al , 2001Watts et al 2004;Brown et al 2006;Pornsoping et al 2007) and strategies to mitigate temperature stress in broodstock (Dzikowski et al 2001;King and Pankhurst 2004b;Vikingstad et al 2008). Conversely, fewer studies were conducted to address temperature exposures in fish within an ecological or conservation context (Buckley et al 1990;Bonner et al 1998;Ouellet et al 2001;St Mary et al 2001;Hilder and Pankhurst 2003;Ito et al 2008).…”