scholarly journals Coastal migrations, temporary use of neighbouring rivers, and growth of sea trout (Salmo trutta) from nine northern Baltic Sea rivers

2012 ◽  
Vol 69 (6) ◽  
pp. 971-980 ◽  
Author(s):  
Erik Degerman ◽  
Kjell Leonardsson ◽  
Hans Lundqvist
Keyword(s):  
Baltic Sea ◽  
Salmo Trutta ◽  
Population Decline ◽  
Movement Pattern ◽  
Large Rivers ◽  
Small Rivers ◽  
Sea Trout ◽  
Management Plans ◽  
Length Increment ◽  
The Baltic

Abstract Degerman, E., Leonardsson, K., and Lundqvist, H. 2012. Coastal migrations, temporary use of neighbouring rivers, and growth of Sea trout (Salmo trutta) from nine northern Baltic Sea rivers – ICES Journal of Marine Science, 69: 971–980. The wild migratory trout (Salmo trutta) stocks in the northern Baltic Sea are threatened, and the fishery is thought to play a significant role in the population decline. Therefore, knowledge about the migration patterns of these stocks is needed to develop appropriate management plans. For this reason, we analysed the movement pattern from recaptures of mandatory releases of tagged hatchery-reared trout smolt from nine rivers in the region (1998–2007). The median time from release until recapture was 366 days, and the median migration distance at recapture was 27 km, with a dominating southward direction for northern stocks. Most of the recaptured fish were immature (65%), and recaptures in rivers (55%) dominated over recaptures along the coast (44%). Riverine recaptures were most frequent during autumn–spring. A total of 16% of all recaptures in rivers occurred in non-natal rivers. Straying was about twice as frequent among fish from small rivers as from large rivers. The results from the river Gideälven indicate that using broodstock from other rivers in stocking programmes may lead to a high proportion of strayers. In addition, temporary use of neighbouring rivers was more frequent in large rivers during winter. Growth, in terms of length increment, was high, especially in fish from southern parts of the Baltic, and higher than in neighbouring warmer and more saline sea areas.

Effects of marine conditions, fishing, and smolt traits on the survival of tagged, hatchery-reared sea trout (Salmo trutta trutta) in the Baltic Sea

2007 ◽  
Vol 64 (9) ◽  
pp. 1183-1198 ◽  
Author(s):  
Irma Kallio-Nyberg ◽  
Irma Saloniemi ◽  
Eero Jutila ◽  
Ari Saura
Keyword(s):  
Survival Rate ◽  
Baltic Sea ◽  
Salmo Trutta ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Survival Rates ◽  
Clupea Harengus ◽  
The Baltic Sea ◽  
Sea Trout ◽  
The Baltic

The marine survival of tagged sea trout (Salmo trutta trutta) smolt groups (n  =  236) stocked from 1970 to 2001 in the Baltic Sea was analysed using a linear mixed model. The response variable, survival rate, was associated with smolt size, release date, sea surface temperature in May, and prey fish abundance, and interactions among these factors. The effect of smolt size was in interaction with Baltic herring (Clupea harengus membras) abundance; smolt size had an optimum of about 22 cm in years when herring were abundant, but when herring were less abundant, the survival of larger smolts was higher. Early stocking in warm springs or late stocking in cold springs gave the best survival rates for trout. Changes in return activity or fishing methods have made tag returns a less reliable way of estimating survival during the last 30 years. The actual return rate of undersized fish (<40 cm) compared with their estimated proportion among captured fish decreased over time, which suggests that the survival rate for the later years was probably underestimated. It is likely that we were unable to include all the relevant explanatory variables in the model, as year effects remained significant, suggesting unknown annual variation affecting survival.

scholarly journals How effective are River Basin Management Plans in reaching the nutrient load reduction targets?

AMBIO ◽  
2020 ◽  
Author(s):  
Mikołaj Piniewski ◽  
Sirkka Tattari ◽  
Jari Koskiaho ◽  
Olle Olsson ◽  
Faruk Djodjic ◽  
...  
Keyword(s):  
Baltic Sea ◽  
River Basin ◽  
River Basin Management ◽  
Load Reduction ◽  
Nutrient Loads ◽  
Basin Management ◽  
The Baltic Sea ◽  
River Basin Management Plans ◽  
Management Plans ◽  
The Baltic

Abstract Riverine nutrient loads are among the major causes of eutrophication of the Baltic Sea. This study applied the Soil & Water Assessment Tool (SWAT) in three catchments flowing to the Baltic Sea, namely Vantaanjoki (Finland), Fyrisån (Sweden), and Słupia (Poland), to simulate the effectiveness of nutrient control measures included in the EU’s Water Framework Directive River Basin Management Plans (RBMPs). Moreover, we identified similar, coastal, middle-sized catchments to which conclusions from this study could be applicable. The first modelling scenario based on extrapolation of the existing trends affected the modelled nutrient loads by less than 5%. In the second scenario, measures included in RBMPs showed variable effectiveness, ranging from negligible for Słupia to 28% total P load reduction in Vantaanjoki. Adding spatially targeted measures to RBMPs (third scenario) would considerably improve their effectiveness in all three catchments for both total N and P, suggesting a need to adopt targeting more widely in the Baltic Sea countries.

scholarly journals Climate Change Impact on Salmon (Salmo salar) and Sea Trout (Salmo trutta) in the Salaca River, Latvia

2020 ◽  
pp. 17-26
Author(s):  
Janis Birzaks
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Salmo Trutta ◽  
Age Groups ◽  
Average Water Temperature ◽  
Sea Trout ◽  
The One ◽  
The Baltic

Hydrometeorological conditions are important determinants of the distribution, abundance and growth of Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) parr and smolt in rivers. Long-term monitoring of the temperate zone Salaca River was conducted to investigate long-term changes in water temperature and streamflow and their effects on juvenile Atlantic salmon and sea trout. The average water temperature in the Salaca River was found to increase over time, particularly in autumn, winter and spring. River discharge increased in winter and summer, which was caused by increased precipitation. Goals of our study were: 1) to examine trends in water temperature and discharge in the river, 2) to explore relations between hydrometeorological trends, on the one hand, and abundance, size at age of salmon and sea trout parr and smolt, as well as changes in smolt migration patterns, on the other. This was the first occasion that a study of this type had been carried out in the Baltic Sea basin. In summer, growth of salmon parr in all age groups in the Salaca River was reduced. However, the size of smolt was found to increase. Migration of sea trout smolt in the Salaca River took place earlier, and the end of both salmon and sea trout migration was also observed earlier. The age structure of salmon smolt changed, with the one-year- old age group dominating. Judging from the total numbers of salmon and sea trout smolt in the River Salaca, production of smolt in the river during the monitoring period increased.

scholarly journals MICROBIOLOGICAL STUDY OF BALTIC SEA AND GULF OF RIGA COAST BATHING WATERS

2001 ◽  
Vol 1 ◽  
pp. 217
Author(s):  
Astrīda Zandmane
Keyword(s):  
Water Quality ◽  
Baltic Sea ◽  
Coastal Zone ◽  
National Standard ◽  
Small Rivers ◽  
The Baltic Sea ◽  
Bathing Water ◽  
Bathing Waters ◽  
Gulf Of Riga ◽  
The Baltic

This report focuses on the studies o f the bathing water microbiological quality in Latvian coastal zone of the Baltic sea and the Gulf of Riga in May-October, 1998-1999. The microbiological studies has been done in the different coastal zones of Kurzeme and Vidzeme, downstreams o f small rivers and biggest rivers Venta and Gauja, discharges o f wastewater treatment plants and the public bathing waters in Ventspils and Saulkrasti municipality area to assess their quality according to the EU Blue Flag and Latvian National Standard criteria. The microbiological examinations were carried out in accordance with the International Standard Methods. A complex of indicatororganisms - total and thermotholerant coliforms (E.coli), streptococci, and heterotrophicplate count (37°,21°C) has been tested. Water quality in the Kurzeme has been found much better on the beaches of the Baltic sea than the most urbanised beaches of Gulf o f Riga. The quality o f the Ventspils public bathing waters has been evaluated as very good (80-100% o f data). Whereas as a result of anthropogenic load only 61-82% o f data conforms the obligatory requirements of the bathing water quality in Saulkrasti coastal zone. In the study the microbiological pollution, sources and levels of their dynamics and hydrological factors are interpreted. The colour maps o f the bathing waters quality are presented.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Baltic Sea ◽  
Fish Species ◽  
Salmo Trutta ◽  
Anthropogenic Activities ◽  
Life Stage ◽  
Yolk Sac ◽  
Reproductive Disorders ◽  
Top Predators ◽  
Declining Populations ◽  
The Baltic

<em>Abstract.—</em>Populations of Baltic salmon <em>Salmo salar </em>and cod <em>Gadus morhua </em>are facing acute threats because of poor reproduction. The salmon is afflicted with high yolk sac fry mortality, and the incidence of cod larvae mortality is high. There are also indications that anadromous Baltic brown trout <em>Salmo trutta </em>populations are affected by reproductive disorders. These top predators have significant ecological, economic, and socioeconomic importance. Other species are also suffering from poor reproductive success and declining populations. Burbot <em>Lota lota </em>populations are locally affected by inadequate sexual maturation, resulting in a failure to spawn; gonad anomalies have also been described in roach <em>Rutilus rutilus</em>. High egg mortality has been recorded for whiting <em>Merlangius merlangus</em>, flounder <em>Platichtys flesus</em>, and herring <em>Clupea harengus</em>. Attempts have been made to discover the cause of reproductive disorders in Baltic fish species, but the available data suggest several possible causes, both abiotic and biotic. Species with pelagic eggs such as cod and flatfish are dependent on salinity and oxygen concentrations, factors that often limit the volume of reproduction in the Baltic Sea. A variety of biotic causes (i.e., infectious diseases, parasitism, and toxic algae) have been shown to affect species such as roach and herring. There are indications that nutritional factors (i.e., thiamine and astaxanthin) are involved in the cause of the yolk sac fry mortality syndrome affecting the Baltic salmon. Furthermore, anthropogenic activities causing both local point sources (i.e., metals and persistent organic pollutants) and long-range transport and deposition of acidic rain and pesticides must also be considered as potential threats to Baltic fish species.

Survival of reared Atlantic salmon and sea trout in relation to marine conditions of smolt year in the Baltic Sea

2006 ◽  
Vol 80 (2-3) ◽  
pp. 295-304 ◽  
Author(s):  
Irma Kallio-Nyberg ◽  
Eero Jutila ◽  
Erkki Jokikokko ◽  
Irma Saloniemi
Keyword(s):  
Atlantic Salmon ◽  
Baltic Sea ◽  
The Baltic Sea ◽  
Sea Trout ◽  
The Baltic
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