Unpredictability of fish recruitment: interannual variation in young–of–the–year abundance

Abstract

In 1989-1998, vendace larvae Coregonus albula were sampled in Finnish lakes following a stratified random sampling design. The abundance of young-of-the-year vendace after the first growing season was estimated using catch-per-unit-effort statistics. The number or total area of nursery places hardly limited the recruitment of vendace in the study lakes. The major proportion of prerecruit mortality of vendace occurred in the larval phase and larval sampling produced significant information on young-of-the-year survival. Although larval abundances and recruitment were clearly associated only in Lake Onkamo, generally high larval abundance was needed to produce high number of recruits. 2000 The Fisheries Society of the British Isles

Density and biomass of smelt (Osmerus eperlanus) in five Finnish lakes

“…In L. Paasivesi in 1984-1991 the density of adult vendace was assessed at 59-949 specimens ha −1 (Auvinen and Jurvelius, 1994). The respective figure for age 0+ vendace has varied between 0 and 5000 in Finnish boreal lakes in 1971-1997(Helminen et al, 1993Auvinen, 1994;Auvinen et al, 2000;Karjalainen et al, 2000). However, because vendace specimens are generally larger than smelt, the biomass of vendace is usually greater than that of a smelt population of the same abundance.…”

Population size estimation of larval coregonids in large lakes: Stratified sampling design with a simple prediction model for vertical distribution

“…larvae has been monitored intensively in Finnish lakes for 17 years. These estimates have produced important information on survival in the early stages of life (Helminen et al, 1997;Auvinen et al, 2000;Karjalainen et al, 2000;Marjomäki et al, 2004). Larval densities have been estimated by a stratified sampling design with bongo nets Viljanen and Karjalainen, 1992;Karjalainen et al, 1998).…”

“…Since a large proportion of the mortality in fish populations occurs during the early stages, i.e., from spawning to the juvenile stage (Bradford and Cabana, 1997;Auvinen et al, 2000;Karjalainen et al, 2000;Houde, 2002;Marjomäki et al, 2004), reliable estimates of the abundance of newly hatched larvae are often required for early predictions of recruitment success and fisheries management.…”

Feeding mechanism and capture success of european whitefish (Coregonus lavaretusL.) larvae

“…In Lake Geneva, the increase of whitefish catches is partly due to the change of stocking practices from only yolk-sac fry to the following different stages : yolk-sac fry, juveniles (< 3 cm) and fingerlings (5-6 cm) (Gerdeaux, 2004). For this genus, in which the highest pre-recruitment mortality occurs during the larval stage (Karjalainen et al, 2000), little is known about the factors governing the catch success and the survival of its larval stages. Although many studies have identified several mechanisms involved in the capture success of fish larvae, less attention has been paid to the role of the larvae's path complexity.…”

“…The recruitment of pelagic fish species with high reproductive potential is highly variable, irrespective of marine (Koutsikopoulos and Le Cann, 1996) or fresh water species (Müller, 1992;Karjalainen et al, 2000). Successful recruitment relies on adult spawning stocks (Helminen et al, 1997), physical factors (Sirois and Dodson, 2000;Munk, 2007) and the availability of appropriate zooplankton prey (Rao, 2003).…”