Analysis of trophic networks and carbon flows in south-eastern Baltic coastal ecosystems

Effects of small-scale and recreational fisheries on the Gran Canaria ecosystem

“…The FCI of the Gran Canaria marine ecosystem is only 12.6%, so it is a moderate value, consistent with results obtained in Mediterranean models (Coll et al, 2007;Tsagarakis et al, 2010), and lower than values obtained in lagoons, bays and estuaries (Baird and Ulanowicz, 1993;Rybarczyk and Elkaim, 2003) where cycling and decomposition processes are very important. The relatively high PCI (7.9%) suggest the importance of predation at higher trophic levels in the structure and functioning of the ecosystem (Tomczak et al, 2009). Ascendency (A) presented a low value (25.5%), but in line with results obtained in South Catalan Sea (Coll et al, 2006), Adriatic Sea (Coll et al, 2007) and Aegean Sea (Tsagarakis et al, 2010).…”

Ecological Network Indicators of Ecosystem Status and Change in the Baltic Sea

“…[19] used the ENA method to compare the Baltic Sea to Chesapeake Bay and Tomczak et al . [20] used ENA to compare coastal ecosystem maturation and stress in five coastal ecosystems. However, none of these Baltic related ENA studies took temporal changes in the ENA indices and regime shifts into account.…”

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

“…Further, our model does not take into account whether Pärnu Bay can provide enough food for a doubled or tripled pikeperch population. A recent food web model (Tomczak et al 2009) indicates that in Pärnu Bay piscivores, especially the quantitatively dominating perch, exert the strongest top-down control on planktivores within the five coastal ecosystems studied. This suggests that food competition will play a role if there is a large increase in piscivorous fish populations.…”

“…Further, we compared this estimate to the potential revenue from fishing herring, which is the major pikeperch prey. The potential revenue from fishing the annual herring consumption of the pikeperch stock was based on a first price of €0.15 · kg -1 for herring, an annual consumption rate of 6.0 times the total stock biomass, similar to Pärnu Bay piscivore consumption in Tomczak et al (2009), and an 80% share of herring in the pikeperch diet (Ojaveer et al 1997).…”