Challenges and Opportunities of Local Fisheries Management: Pikeperch, Sander Lucioperca (Actinopterygii: Perciformes: Percidae), in Pärnu Bay, Northern Gulf of Riga, Baltic Sea

Consequences of size-selective harvesting and changing climate on the pikeperch Sander lucioperca in two large shallow north temperate lakes

“…In Lake Peipsi, the reduction of in the legal size had no significant effect on the average pikeperch length or the pikeperch in catches; however, Müller- Karulis et al (2013) stated that pikeperch stocks are very sensitive to immature fish catches. There might be several reasons for this lack of effect in Lake Peipsi.…”

“…(Lappalainen et al, 1997;Müller-Karulis et al, 2013). In Estonia, the mean air temperature has increased approximately 1 • C since the 19th century (Jaagus, 2006;Tarand et al, 2013), and the phosphorus concentrations of large lakes are only slightly higher than the level considered optimal for pikeperch populations (30 mg P m −3 according to Helminen et al, 2000).…”

“…Although considerable research has been conducted regarding the juvenile stages of pikeperch in lakes (van Densen, 1985;Persson and Brönmark, 2008;Peterka et al, 2003;Ginter et al, 2011Ginter et al, , 2012a, less attention has been given to the long-lasting commercial size-selective exploitation of pikeperch in lakes and the effects of this exploitation on lake ecosystems. Instead, studies have focused on brackish waters (Eero, 2004;Gröger et al, 2007;Müller-Karulis et al, 2013;Mustamäki et al, 2014).…”

Seasonal depth distribution and thermal experience of the non-indigenous round goby Neogobius melanostomus in the Baltic Sea: implications to key trophic relations

“…Grey seal (Halichoerus grypus), and also to some extent harbour seal (Phoca vitulina), likewise consume round goby in the southern and southwestern Baltic Sea. While the share of round goby in harbour seal diet in 2001-2005 and 2013 was negligible (1%), round goby constituted 17% of the grey seal diet in 2012-2013(Scharff-Olsen et al 2019). More recently (2017), round goby was the fish species with the highest occurrence in scats from a haul-out site by Rødsand (where round goby were first observed in 2011; Azour et al 2015), occurring in 45 to 62% of the scats sampled in spring, summer and autumn in 2017 (no samplings in winter) (Kroner unpubl.…”

“…This effect may further cascade in the foodweb and affect recruitment abundance of a very valuable coastal commercial species-pikeperch (Zander lucioperca), for which larvae and early juveniles of Pomatoschistus spp. serve as the primary prey for early juveniles (Mu ¨ller- Karulis et al 2013). Although there is evidence that juvenile pikeperch can prey on the round goby (Hempel et al 2016), the net effect of the round goby on the early juvenile stages of pikeperch is likely reduction of its primary food resource.…”