Short sea migration and precocious maturation in reared Atlantic salmon post-smolts in the northern Baltic Sea

2017 ◽  
Vol 75 (3) ◽  
pp. 1063-1070 ◽  
Author(s):  
Panu Orell ◽  
Jaakko Erkinaro ◽  
Mikko Kiljunen ◽  
Jyrki Torniainen ◽  
Tapio Sutela ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Baltic Sea ◽  
Isotope Analysis ◽  
History Of ◽  
The Baltic ◽  
Bothnian Bay ◽  
Almost All ◽  
Induced Changes ◽  
Sea Area

Abstract Atlantic salmon (Salmo salar L.) display significant variation in life history traits, including migration patterns and age at maturity. Hatchery rearing has been shown to affect the life history, and rearing-induced changes may include unfavourable consequences, e.g. shortened sea migration period and smaller size at maturity. We report on a new phenomenon of life history of reared Atlantic salmon in the Baltic Sea area: small-sized salmon returning to freshwater only a few months after release as smolts. These “one-sea-summer (1SS)” salmon were ca. 35 cm in length and weighed ca. 400 g, being clearly larger than smolts, but substantially smaller than one-sea-winter (1SW) salmon from the same cohorts. Almost all 1SS salmon were mature males and, at release, had been longer than the overall mean. Stable isotope analysis suggested that the 1SS salmon had been feeding in different sea areas than 1SW and multi-sea-winter salmon, likely in nearby Bothnian Bay, which is typically not a salmon feeding area. If an increasing proportion of the released salmon are not undertaking a normal marine migration (≥1SW) and are returning to estuaries and rivers as 1SS fish, the success and profitability of the reared salmon releases will decline even more than the reduced post-smolt survival is suggesting. We suggest that alternative rearing practices (e.g. enriched rearing environments and advanced diets) should be considered in hatchery production for shaping the reared smolts towards a closer resemblance to wild smolts.

Variations of 87Sr/86Sr in Water from Streams Discharging into the Bothnian Bay, Baltic Sea

1987 ◽  
Vol 18 (1) ◽  
pp. 33-42 ◽  
Author(s):  
F. Åberg ◽  
F. E. Wickman
Keyword(s):  
Baltic Sea ◽  
Water Samples ◽  
Isotope Ratio ◽  
Stream Water ◽  
Weighted Average ◽  
High Ratio ◽  
Drainage Basins ◽  
History Of ◽  
The Baltic ◽  
Bothnian Bay

The 87Sr/86Sr ratio in 53 water samples were analysed, 26 from streams in Sweden, 22 from streams in Finland and 5 from the Bothnian Bay itself. The brackish seawater of the bay had the isotope ratio 0.7095, while the stream-water samples varied from 0.7177 to 0.7366. The weighted average isotope ratio with respect to discharges was 0.7313, this high ratio reflecting the dominance of granitic Proterozoic rocks in the region. For streams with an average discharge between 1-40 m3/s the isotope ratio was within the interval 0.718-0.736, while those with discharges >150 m3/s defined an interval of 0.728-0.735. The variations in isotope ratios are discussed with respect to bedrock geology of drainage basins, possible effects of seawater inundations and Postglacial uplift combined with the complex history of the Baltic Sea.

scholarly journals On the supposed first stage larva of Leptohylemyia coarctata, Fall.

1917 ◽  
Vol 8 (2) ◽  
pp. 121-123 ◽  
Author(s):  
D. Keilin
Keyword(s):  
Life History ◽  
Recent Work ◽  
European Countries ◽  
Stage Larva ◽  
History Of ◽  
Almost All

It has been well known since the studies of Taschenberg (1864–1872) that the larvae of Leptohylemyia coarctata, Fall., attack wheat and rye. The damage due to this fly has been observed many times in almost all European countries, and many papers have been devoted to its life-history. Of these papers the most important are those of E. Ormerod (1882–1895), S. Rostrup (1905–1911), T. Hedlund (1906- 1907), P. Marchal (1909) and finally the recent work of Kurdjumov (1914).

Contacts and Networks in the Baltic Sea Region

2019 ◽  
Keyword(s):  
Baltic Sea ◽  
Final Section ◽  
Religious Studies ◽  
The Baltic Sea ◽  
Cultural Goods ◽  
The Third ◽  
Baltic Sea Region ◽  
The World ◽  
History Of ◽  
The Baltic

Since prehistoric times, the Baltic Sea has functioned as a northern mare nostrum — a crucial nexus that has shaped the languages, folklore, religions, literature, technology, and identities of the Germanic, Finnic, Sámi, Baltic, and Slavic peoples. This anthology explores the networks among those peoples. The contributions to Contacts and Networks in the Baltic Sea Region: Austmarr as a Northern mare nostrum, ca. 500-1500 ad address different aspects of cultural contacts around and across the Baltic from the perspectives of history, archaeology, linguistics, literary studies, religious studies, and folklore. The introduction offers a general overview of crosscultural contacts in the Baltic Sea region as a framework for contextualizing the volume’s twelve chapters, organized in four sections. The first section concerns geographical conceptions as revealed in Old Norse and in classical texts through place names, terms of direction, and geographical descriptions. The second section discusses the movement of cultural goods and persons in connection with elite mobility, the slave trade, and rune-carving practice. The third section turns to the history of language contacts and influences, using examples of Finnic names in runic inscriptions and Low German loanwords in Finnish. The final section analyzes intercultural connections related to mythology and religion spanning Baltic, Finnic, Germanic, and Sámi cultures. Together these diverse articles present a dynamic picture of this distinctive part of the world.

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