Marking and return method for evaluating the effects of stocking larval vendace, Coregonus albula (L.), into Lake Wigry in 2000-2001

Abstract

Abstract. In 2000 and 2001, larval vendace, Coregonus albula (L.), were marked and released into Lake Wigry. The larvae were immersed in alizarin red S. Of the 19.2 million vendace larvae released in 2000, 2 million were marked (10.4% of the overall number of fish released), and in 2001 of the 18.8 million fish released, 7 million were marked (47.8%). In subsequent years, otoliths were excised from caught vendace and the number of them with alizarin marks was determined. It was assumed that all unmarked specimens came equally from natural spawning and stocking assuming that survival is equal in both forms of recruitment. It was confirmed that 82.4% of the vendace caught from the 2000 generation originated from stocking, while this figure was 64.2% of all specimens caught from the 2001 generation. Lake Wigry hosts the most abundant vendace population in Poland, and this stock spawns on a massive scale annually. Even so, the study described herein provides evidence of just how important systematic stocking is to the maintenance of the vendace population in this lake.

Early detection of reproduction deficits and the compensatory potential of enhancement stocking for vendace, Coregonus albula, fisheries in German lakes

“…(), Poczyczyński et al . () and Eckmann et al . (), but the latter concluded that strong natural recruitment in the year of enhancement stocking has caused the low efficiency of the stocking measure.…”

“…Among the few studies on vendace enhancement stocking, such a high contribution of hatchery fish has only been shown by Poczyczyński et al . (), whereas Eckmann et al . () and Mehner et al .…”

“…There was a strong contribution of stocking to cohort strength and yield of a vendace fishery. Among the few studies on vendace enhancement stocking, such a high contribution of hatchery fish has only been shown by Poczyczy nski et al (2011), whereas Eckmann et al (1998 and Mehner et al (2009) found negligible contributions of stocking to vendace populations in several German lakes. These contradicting results illustrate that the contribution of stocked vendace to the standing stock and hence potential additive effects are not necessarily a consequence of enhancement stocking.…”

“…and natural recruits in the subsequent catches (Turkowski & Bonar 1995;. Other studies focused primarily on the survival and growth of stocked larvae, whereas the natural stock and its reproduction and recruitment were ignored (Eckmann et al 1998;Mehner et al 2009;Poczyczy nski et al 2011).…”

Mass marking of stocked European glass eels (Anguilla anguilla) with alizarin red S

“…This low-stress method (Lagardere et al 2000;Ibanez et al 2013) is particularly suitable for small fishes or those at an early life stage (Alcobendas et al 1991). Combined with stocking operations, mass marking by bath has provided an effective way to acquire knowledge about life history and to evaluate the results of management programmes on eel species (Meunier 1994;Verreault et al 2010;Desprez et al 2013; Wickstr€ om & Sj€ oberg 2013), or other fishes (Baer & R€ osch 2008;Caudron & Champigneulle 2009;Poczyczynski et al 2011). Combined with stocking operations, mass marking by bath has provided an effective way to acquire knowledge about life history and to evaluate the results of management programmes on eel species (Meunier 1994;Verreault et al 2010;Desprez et al 2013; Wickstr€ om & Sj€ oberg 2013), or other fishes (Baer & R€ osch 2008;Caudron & Champigneulle 2009;Poczyczynski et al 2011).…”