When to count your eggs: Is fecundity in Greenland halibut (Reinhardtius hippoglossoides W.) down-regulated?

Abstract

Fecundity in several fish species is subject to down-regulation by atresia so if fecundity is estimated many months before spawning, this will be an overestimation of the realised fecundity (actual number of eggs spawned). In order to get accurate measurements of fecundity it is important to have knowledge on when potential fecundity (estimated fecundity at time of sampling) closely resembles the realised fecundity. Down-regulation of fecundity for Greenland halibut (Reinhardtius hippoglossoides W.) was assessed using fish caught off East Greenland 1998, 1999 and 2000. The fish caught in 1998 and 1999 were in an early and late stage of vitellogenesis respectively of the same maturation cycle. The fish caught in 2000 were also at an early stage of vitellogenesis. Fecundity decreased by 43% between early and late vitellogenesis. Fecundity in 1999 appeared to be the second lowest recorded for Greenland halibut but it is believed to be due to developmental stage rather than low productivity. There was no difference in fecundity between 1997 and 1998. It is believed that differences in fecundity between years only become apparent in late maturation as size during oocyte recruitment has a very large influence on fecundity. Neither Fulton's condition nor hepatosomatic index had any significant influence on fecundity.

Developments in understanding of fecundity of fish stocks in relation to egg production methods for estimating spawning stock biomass

“…This has been shown in a range of species (e.g. Thorsen et al, 2006 andSkjaeraasen et al, 2010, for Atlantic cod;Kennedy et al, 2007Kennedy et al, , 2008 for plaice; van Damme et al, 2009b, for herring;Kennedy et al, 2009 for Greenland halibut Reinhardtius hippoglossoides).…”

Influence of a large dam and importance of an undammed tributary on the reproductive ecology of the threatened fish matrinxã Brycon orthotaenia Günther, 1864 (Characiformes: Bryconidae) in southeastern Brazil

“…Fecundity estimates are essential for determining the reproductive potential of fish species, and their values are important for understanding the biological status and the reproductive potential of a population (Kennedy et al, 2009). When compared to some other Neotropical teleosts, like those with non-migratory strategy, B. orthotaenia showed a high fecundity, a common characteristic for migratory fish that exhibit total spawning (Arantes et al, 2011;Freitas et al, 2013).…”

Spatial and annual variation in fecundity and oocyte atresia of yellowtail flounder, Limanda ferruginea, in U.S. waters

“…Decreases in potential fecundity of 45% have been reported for Greenland halibut, Reinhardtius hippoglossoides (Kennedy et al, 2009), 27-30% in Atlantic cod, G. morhua (Witthames et al, 2013), and 20-71% in Atlantic herring, Clupea harengus (Bucholtz et al, 2013;Kurita et al, 2003;van Damme et al, 2009). Downregulation may also occur at earlier stages of oogenesis than examined here; as in some species where it has been found to be lower just prior to spawning and higher during an earlier 'atretic' window (Kennedy et al, 2009;Kurita et al, 2003). Down-regulation of yellowtail flounder was found to occur throughout late vitellogenesis.…”

“…Intrapopulation differences have been observed within Grand Bank yellowtail flounder (Morgan and Rideout, 2008;Rideout and Morgan, 2007) as well as other flatfish (Kennedy et al, 2007;Rijnsdorp, 1991), but not in all cases where it has been examined (Kennedy et al, 2009;Nichol and Acuna, 2001). Spatial heterogeneity in condition has been identified in yellowtail flounder on Georges Bank (Pereira et al, 2012); therefore based on the present results it is expected that fecundity will covary among Georges Bank habitats with condition.…”