Life‐history characteristics of ide Leuciscus idus in the Eastern Baltic Sea

Abstract

Otolith Sr:Ca and Ba:Ca profiles were used in parallel with age data to investigate the life‐history characteristics of ide, Leuciscus idus (L.) (n = 111), in the Väinameri Sea, West Estonia. Sr:Ca profiles were more variable and useful than Ba:Ca profiles. Flexible life‐history patterns were observed within and among the three study sites. Most of the individuals (72%) hatched in semi‐enclosed bays that are fresh water during spring spawning but are often flooded with brackish water during other seasons. The importance of lotic spawning varied among sites and was the highest (88%) in Matsalu Bay, moderate in Saunja Bay (33%) and lowest (0%) in Käina Bay. Young of the year emigrated from natal sites and entered the sea within the first summer; 95% did so during the first month post‐hatch. Juvenile ide undertook non‐spawning, freshwater migrations in the following spring; however, the reasons behind this phenomenon remain unknown. As the importance of lotic spawning has significantly decreased and multiple historically important ide spawning rivers lack anadromous runs altogether, it is suggested that actions should be taken to aid the recovery of those imperilled spawning stocks.

Do Eurasian minnows (Phoxinus phoxinus L.) inhabiting brackish water enter fresh water to reproduce: Evidence from a study on otolith microchemistry

“…Considering the aforementioned ontogenetic effect on the core Sr:Ca values, we cannot assign analysed minnows hatching habitat for certain, except for two specimens from the Jämaja Brook, which showed very low natal Sr values (Sr:Ca <0.5 mmol mol −1 ). Water chemistry data and previous studies (Rohtla et al., , , ) suggest that Sr:Ca natal values ≤0.6 mmol mol −1 should be considered as fresh water. This indicates that those two individuals were hatched in fresh water and had freshwater natal rearing habitat.…”

“…Strontium‐to‐calcium ratio in the water is generally positively correlated with salinity (Limburg, ; Zimmerman, ), and those ambient Sr:Ca values are reflected in the otoliths (Bath et al., ; Kraus & Secor, ). Several previous studies have successfully used otolith microchemistry (Sr:Ca as a chemical tracer) for studying fish movements in the Baltic Sea, although, yet again, research has been focused on economically valuable species (Limburg, Landergren, Westin, Elfman, & Kristiansson, ; Limburg, Wickström, Svedäng, Elfman, & Kristiansson, ; Rohtla et al., ; Shiao, Ložys, Iizuka, & Tzeng, ; Taal, Kesler et al., ).…”

Genomic population structure of freshwater‐resident and anadromous ide (Leuciscus idus) in north‐western Europe

“…; Rohtla et al. ). Currently, in the western part of the Baltic Sea, species such as these migrate into brackish water close to their maximum salinity tolerance.…”

Parr dispersal between streams via a marine environment: A novel mechanism behind straying for anadromous brown trout?

“…In the Baltic basin the Sr:Ca as a tracker of fish migration is known to have positive relationship between salinity, water Sr:Ca and otolith Sr:Ca (e.g. Engstedt, Koch‐Schmidt, & Larsson, ; Rohtla et al., , ; Svirgsden et al., ). Thus, we expected that individuals who underwent SSME show initial lower Sr:Ca levels, followed by increase and subsequent decrease in Sr:Ca levels.…”

“…A reference glass material (NIST 612) and calcium carbonate standard (MACS-3) were analysed before and after all 20 otoliths. Data were handled following the methods of Miller (2007) as described in Rohtla et al (2014) Rohtla et al, 2014Rohtla et al, , 2015Svirgsden et al, 2016). Thus, we expected that individuals who underwent SSME show initial lower Sr:Ca levels, followed by increase and subsequent decrease in Sr:Ca levels.…”