Warmer water increases early body growth of northern pike (Esox lucius) but mortality has larger impact on decreasing body sizes

Large fish species often display truncated size distributions related to harvest. In addition, temperature, food availability and density-dependence affect body growth, and together with natural mortality influence population size structure. Here we study changes in body growth, size distributions and mortality in both harvested and non-harvested populations of northern pike over 50 years along the Baltic Sea coast and in Lake Mälaren, Sweden. For coastal pike, body growth has increased coincidentally with increasing water temperatures, yet in the last two decades there has been a decrease of larger individuals. In Lake Mälaren, in contrast, size distributions and body growth were stationary despite similar increases in water temperature. A dominance of slow-growing individuals in older age-classes was evident in all studied populations, also in the no-take zone, suggesting other factors than fishing contribute to the mortality pattern. We propose that increasing temperatures have favoured body growth in coastal areas, but this has been counteracted by increased mortality, causing pike sizes to decline. To regain larger coastal pike, managers need to consider multiple measures that reduce mortality.

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Malignant lymphomas of different histological types in the northern pike (Esox lucius) from the eastern part of the Baltic Sea

Aquatic Toxicology ◽

10.1016/0166-445x(88)90122-1 ◽

1988 ◽

Vol 11 (3-4) ◽

pp. 421 ◽

Cited By ~ 2

Author(s):

S. Bogovski

Keyword(s):

Baltic Sea ◽

Northern Pike ◽

Esox Lucius ◽

The Baltic Sea ◽

Malignant Lymphomas ◽

Pike Esox Lucius ◽

Histological Types ◽

The Baltic

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Effects of lure type, fish size and water temperature on hooking location and bleeding in northern pike (Esox lucius) angled in the Baltic Sea

Fisheries Research ◽

10.1016/j.fishres.2014.04.002 ◽

2014 ◽

Vol 157 ◽

pp. 164-169 ◽

Cited By ~ 7

Author(s):

M. Stålhammar ◽

T. Fränstam ◽

J. Lindström ◽

J. Höjesjö ◽

R. Arlinghaus ◽

...

Keyword(s):

Baltic Sea ◽

Water Temperature ◽

Northern Pike ◽

Esox Lucius ◽

The Baltic Sea ◽

Fish Size ◽

Pike Esox Lucius ◽

The Baltic

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Wetlands for northern pike (Esox lucius L.) recruitment in the Baltic Sea

Hydrobiologia ◽

10.1007/s10750-013-1656-9 ◽

2013 ◽

Vol 721 (1) ◽

pp. 145-154 ◽

Cited By ~ 24

Author(s):

Jonas Nilsson ◽

Olof Engstedt ◽

Per Larsson

Keyword(s):

Baltic Sea ◽

Northern Pike ◽

Esox Lucius ◽

The Baltic Sea ◽

Pike Esox Lucius ◽

The Baltic

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Temporally stable, weak genetic structuring in brackish water northern pike (Esox lucius) in the Baltic Sea indicates a contrasting divergence pattern relative to freshwater populations

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2016-0039 ◽

2017 ◽

Vol 74 (4) ◽

pp. 562-571 ◽

Cited By ~ 5

Author(s):

Lovisa Wennerström ◽

Jens Olsson ◽

Nils Ryman ◽

Linda Laikre

Keyword(s):

Genetic Structure ◽

Baltic Sea ◽

Brackish Water ◽

Northern Pike ◽

Esox Lucius ◽

The Baltic Sea ◽

Genetic Structuring ◽

Important Species ◽

Pike Esox Lucius ◽

The Baltic

Understanding spatiotemporal population genetic patterns is important for conservation management of ecologically and socioeconomically important species. This is particularly so in species-poor environments such as the brackish Baltic Sea. We examined over 600 northern pike (Esox lucius), a coastal predator and treasured sport fish, collected over major parts of the Baltic Sea coastline. We found low genetic divergence among populations, indicating a contrasting genetic structure of brackish water coastal spawners compared with previous reports on anadromous Baltic pike migrating up freshwater streams for spawning. A pattern of genetic isolation by distance either over shortest waterway or primarily along the mainland coast with islands as stepping stones suggested that gene flow is primarily taking place among neighboring populations, possibly with some migration over open water. Temporal data showed a stable genetic structure over a decade. Within a single sampling year, however, spatial divergence was larger during spawning than feeding season, indicating increased mixing of populations during the feeding season. Management should assure connectivity among brackish spawning grounds and large population sizes at identified core areas.

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Mobile measurements of ship emissions in two harbour areas in Finland

Atmospheric Measurement Techniques ◽

10.5194/amt-7-149-2014 ◽

2014 ◽

Vol 7 (1) ◽

pp. 149-161 ◽

Cited By ~ 40

Author(s):

L. Pirjola ◽

A. Pajunoja ◽

J. Walden ◽

J.-P. Jalkanen ◽

T. Rönkkö ◽

...

Keyword(s):

Baltic Sea ◽

Particle Number ◽

City Centre ◽

Particulate Emissions ◽

Size Distributions ◽

So2 Emissions ◽

The Baltic Sea ◽

Eu Directive ◽

The Baltic ◽

The City

Abstract. Four measurement campaigns were performed in two different environments – inside the harbour areas in the city centre of Helsinki, and along the narrow shipping channel near the city of Turku, Finland – using a mobile laboratory van during winter and summer conditions in 2010–2011. The characteristics of gaseous (CO, CO2, SO2, NO, NO2, NOx) and particulate (number and volume size distributions as well as PM2.5) emissions for 11 ships regularly operating on the Baltic Sea were studied to determine the emission parameters. The highest particle concentrations were 1.5 × 106 and 1.6 × 105 cm−3 in Helsinki and Turku, respectively, and the particle number size distributions had two modes. The dominating mode peaked at 20–30 nm, and the accumulation mode at 80–100 nm. The majority of the particle mass was volatile, since after heating the sample to 265 °C, the particle volume of the studied ship decreased by around 70%. The emission factors for NOx varied in the range of 25–100 g (kg fuel)−1, for SO2 in the range of 2.5–17.0 g (kg fuel)−1, for particle number in the range of (0.32–2.26) × 1016 # (kg fuel)−1, and for PM2.5 between 1.0–4.9 g (kg fuel)−1. The ships equipped with SCR (selective catalytic reduction) had the lowest NOx emissions, whereas the ships with DWI (direct water injection) and HAMs (humid air motors) had the lowest SO2 emissions but the highest particulate emissions. For all ships, the averaged fuel sulphur contents (FSCs) were less than 1% (by mass) but none of them was below 0.1% which will be the new EU directive starting 1 January 2015 in the SOx emission control areas; this indicates that ships operating on the Baltic Sea will face large challenges.

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Mobile measurements of ship emissions in two harbour areas in Finland

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-6-7149-2013 ◽

2013 ◽

Vol 6 (4) ◽

pp. 7149-7184

Author(s):

L. Pirjola ◽

A. Pajunoja ◽

J. Walden ◽

J.-P. Jalkanen ◽

T. Rönkkö ◽

...

Keyword(s):

Baltic Sea ◽

Particle Number ◽

Particulate Emissions ◽

Size Distributions ◽

So2 Emissions ◽

The Baltic Sea ◽

Particle Volume ◽

Eu Directive ◽

The Baltic ◽

The City

Abstract. Four measurement campaigns by a mobile laboratory van were performed in two different environments; inside the harbour areas in the city center of Helsinki and along the narrow shipping channel near the city of Turku, Finland, during the winter and summer conditions in 2010–2011. The characteristics of gaseous (CO, CO2, SO2, NO, NO2, NOx) and particulate (number and volume size distributions as well as PM2.5) emissions for 11 ships regularly operating on the Baltic Sea were studied to determine the emission parameters. The highest particle concentrations were 1.5 × 106 and 1.6 × 105 cm−3 in Helsinki and Turku, respectively, and the particle number size distributions had two modes. The dominating mode was peaking at 20–30 nm and the accumulation mode at 80–100 nm. The majority of the particle mass was volatile since after heating the sample to 265 °C, the particle volume of the studied ships decreased by around 70%. The emission factors for NOx varied in the range of 25–100 g (kg fuel)−1, for SO2 in the range of 2.5–17.0 g (kg fuel)−1, for particle number in the range of (0.32–2.26) × 1016 particles (kg fuel)−1, and for PM2.5 between 1.0–4.9 g (kg fuel)−1. The ships equipped with SCR had lowest NOx emissions whereas the ships with DWI and HAM had lowest SO2 emissions but highest particulate emissions. For all ships the averaged fuel sulphur contents (FSCs) were less than 1% (by mass) but none of those was below 0.1% which will be the new EU directive from 1 January 2015 in the SOx Emission Control Areas, indicating big challenges for ships operating on the Baltic Sea.

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The influence of uncertainty in target strength on abundance indices based on acoustic surveys: examples of the Baltic Sea herring and sprat

ICES Journal of Marine Science ◽

10.1093/icesjms/fsp086 ◽

2009 ◽

Vol 66 (6) ◽

pp. 1404-1409 ◽

Cited By ~ 2

Author(s):

Svetlana M. Kasatkina

Keyword(s):

Baltic Sea ◽

Size Structure ◽

Stock Assessment ◽

Clupea Harengus ◽

Statistical Characteristics ◽

Target Strength ◽

The Baltic Sea ◽

Abundance Indices ◽

Acoustic Surveys ◽

The Baltic

Abstract Kasatkina, S. M. 2009. The influence of uncertainty in target strength on abundance indices based on acoustic surveys: examples of the Baltic Sea herring and sprat. – ICES Journal of Marine Science, 66: 1404–1409. In situ, target-strength (TS) measurements at 38 kHz and an analysis of biometric fish characteristics are presented for the Baltic Sea herring (Clupea harengus membras) and sprat (Sprattus sprattus). It is demonstrated that the application of two TS–length functions for the Baltic Sea clupeids, the first for young herring and sprat and the second for adult herring, is reasonable, and the two functions can therefore replace the well-known equation used since 1983. Parameters of the proposed relationships, accompanied by their statistical characteristics, are included in a model to obtain uncertainty in acoustically derived abundance indices. Major components of survey uncertainty, such as spatial variability, species composition, and size structure, are also included in the simulation. The proposed TS functions should permit estimates of more realistic abundance dynamics of Baltic Sea clupeids, by years and age groups, thereby providing important information for stock assessment models.

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