The quality of release habitat for reared juvenile flounder, Platichthys flesus, with respect to salinity and depth

Abstract

One prerequisite for a successful stocking programme is the choice of an appropriate release site, which would ensure good growth, survival and recruitment to the local fishery. The influence of different salinity regimes on habitat quality for juvenile flounder, Platichthys flesus (L.), was examined in Danish inshore waters using enclosures to study growth and survival. Three locations were chosen: Virksund (V) -constant low salinity at 10&; Harre Vig (HV) -constant high salinity at 24&; and Hjerk Nor -variable salinity, 0-25&. Fish movement was examined, using a diffusion model, at the first two sites. At HV the fish had unrestricted dispersal opportunity resulting in average individual movement of 45 m day )1 . Fish at V were restricted in dispersal in one direction because of a dam, about which they would concentrate under certain hydrographical conditions. Growth was highest at the locations with stable salinity and mortality highest at the location with variable salinity.

Diet overlap between juvenile flatfish and the invasive round goby in the central Baltic Sea

“…The current study may thus provide a rare insight into the interactions between round goby and recruiting flatfish. The diet composition of flatfish juveniles in the Baltic Sea is relatively well known, regarding both flounder (for example, Aarnio and Bonsdorff, 1997;Aarnio and Mattila, 2000;Andersen et al, 2005) and turbot (Kostrzewska-Szlakowska and Szlakowski, 1990;Aarnio et al, 1996;Nissling et al, 2007;Florin and Lavados, 2010). The shallow, sandy areas functioning as flatfish nursery grounds also host a large number of other fish species (Ustups et al, 2003;Stankus, 2006;Ustups et al, 2007).…”

“…Prey items were aggregated into nine categories: (Aarnio et al, 1996) Bathyporeia pilosa, (Aarnio and Bonsdorff, 1997) other amphipods, (Aarnio and Mattila, 2000) decapods, (Andersen et al, 2005) fish, (BIOR, 2014) molluscs, (de Gouveia, 2011) mysids, (Florin et al, 2009) polychaetes, (Florin and Lavados, 2010) zooplankton, and (Gibson, 1994) other food items. Fish were assigned to different length groups that correspond to ontogenetic shifts and associated changes in their feeding patterns.…”

Genetic population structure in flatfishes and potential impact of aquaculture and stock enhancement on wild populations in Europe

“…Variability in growth of released fishes was partially dependant on habitat suitability (Sparrevohn and Støttrup 2008). Andersen et al (2005) also reported strong effects of the quality of the release habitat (e.g. salinity) on flounder growth and survival.…”

“…Some small-scale releases of hatchery-reared turbot have been also reported, aimed to enhance stocks available for recreational fishing; Paulsen and Støttrup (2004) referred to more than 800,000 reared juvenile turbot released between 1990 and 2002 in Danish waters. Some experimental releases of flounder have also been performed in Danish waters (Andersen et al 2005).…”

Quantitative Evaluation of Post-Release Mortality Using Salt Pond Mesocosms: Case Studies of Hatchery and Wild Juvenile Tiger Puffer

“…Juvenile quality includes development of normal coloration and morphology (Browman, 1989;Svåsand et al, 1998), normal feeding, and anti-predator behavior (Olla et al, 1994;Tsukamoto et al, 1999;Miyazaki et al, 2000;Masuda, 2004). Specific release strategies can be produced using information about the optimal size of release (Tsukamoto et al, 1989;Yamashita et al, 1994;Leber, 1995;Kristiansen et al, 2000), the release season, size-season interactions (Leber et al, 1997;Sanchez-Lamadrid, 2002), and the place of release (Leber et al, 1996;Andersen et al, 2005), in addition to effects of acclimation (Hamasaki et al, 2004;Brennan et al, 2006). However, these factors for fish quality and release strategy have complex interactions.…”