Parental and stock effects on larval growth and survival to metamorphosis in winter flounder (Pseudopleuronectes americanus) Ian A.E. Butts ⁎ , Matthew K. Litvak Department of Biology and Centre for Coastal Studies and Aquaculture, University of New Brunswick (Saint John), Ganong Hall, P.O. Box 5050, Saint John, New Brunswick, Canada E2L 4L5 Received 9 June 2006; received in revised form 4 April 2007; accepted 7 April 2007 Abstract Geographically separated winter flounder (Pseudopleuronectes americanus) populations in the northwest Atlantic Ocean are both phenotypically and genetically distinct from one another. This has important implications for winter flounder aquaculture with respect to broodstock selection; however, few studies have investigated the effect of population on larval growth and survival in a hatchery setting. In this study, eggs from Passamaquoddy Bay females were fertilized with sperm from Georges Bank and Passamaquoddy Bay males. Larvae were reared in common environmental conditions to evaluate population and parental contributions to variations in growth, and survival during early life history. Mixed-model nested ANOVAs revealed that larvae sired by Georges Bank males were significantly larger with respect to standard length, eye diameter, head depth, and jaw length during certain stages in larval development. Maternal, paternal, and parental interactions all contributed to morphological variation in developing larvae. Survival was strongly influenced by the paternal variance component. These results have two major implications: 1) they provide further supporting evidence that Georges Bank winter flounder are genetically selected for faster growth than larvae from inshore stocks, and 2) they suggest that aquaculture operations should also account for paternal variation so that the best broodstock can be selected for production. © 2007 Elsevier B.V. All rights reserved. Keywords: Winter flounder; Stock; Parental; Georges Bank 1. Introduction Winter flounder ( Pseudopleuronectes americanus) has been identified as a species with potential for aquaculture in Atlantic Canada and the Northeast United States (Howell and Litvak, 2000; Litvak, 1994, 1996, 1999). These fish possess several desirable characteristics for aquaculture. They are euryhaline (McCracken, 1963), and eurythermal (Pearcy, 1961, 1962; Duman and DeVries, 1974), they respond well to stripping of gametes (Rideout et al., 2003), can be photo-manipulated to produce good quality eggs seven months of the year (Butts, unpublished data), their sperm can be cryopreserved (Rideout et al., 2003), and they process antifreeze proteins that allow then to survive temperatures less than - 1 °C (Pearcy 1961; Duman and DeVries, 1974). Overall winter flounder are an extremely hardy fish; however, a major developmental constraint for winter flounder aquaculture is the lack of knowledge of larval growth and survivorship to the juvenile stage (Litvak, 1999). Larval growth and survival are the most important traits during hatchery production and define the success Aquaculture 269 (2007) 339 – 348 www.elsevier.com/locate/aqua-online ⁎ Corresponding author. Tel.: +1 506 529 5873; fax: +1 506 529 5862. E-mail address: buttsi@mar.dfo-mpo.gc.ca (I.A.E. Butts). 0044-8486/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2007.04.012