Evidence of cormorant-induced mortality, disparate migration strategies and repeatable circadian rhythm in the endangered North Sea houting (Coregonus oxyrinchus ): A telemetry study mapping the postspawning migration

Lasse Fast Jensen*, Paul Rognon, Kim Aarestrup, Jesper Wøhlk Bøttcher, Cino Pertoldi, Søren Nøhr Thomsen, Morten Hertz, Jacob Winde, Jon Christian Svendsen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Life history theory predicts a trade-off between migration and residency where migration is favoured when it infers elevated fitness. Although migration to more favourable environments offers higher growth rates, migrants often experience increased mortality due to predation. Here, we investigated mortality and migration behaviour of the North Sea houting (Coregonus oxyrinchus), an anadromous salmonid endemic to the Wadden Sea. We used acoustic telemetry to map the migration of the only remaining indigenous population by applying stationary hydrophones combined with manual tracking. Data suggested a total mortality of 26%, with 30% of the total mortality attributed to predation by great cormorants (Phalacrocorax carbo sinensis), highlighting that North Sea houting conservation could be jeopardised by increased cormorant predation. Risk of cormorant predation was size-dependent, with smaller fish suffering higher risk of predation. The study found North Sea houting to exhibit disparate migration strategies and identified a lentic area in the estuary as an important habitat. Two newly established artificial lakes within the river system significantly reduced the migration speeds, possibly indicating constrained navigation through the lakes. The migration into the Wadden Sea correlated with temperature perhaps indicating osmoregulatory constraints of sea entry. Unlike most salmonid species, migration occurred both day and night. Moreover, fish exhibited repeatable individual differences in diel activity patterns, suggesting that individuals differ consistently in their migratory activity throughout the 24-hr period. Our study provides novel information on salmonid migration, which is crucial for the development of science-based conservation strategies.
Original languageEnglish
JournalEcology of Freshwater Fish
Volume27
Issue number3
Pages (from-to)672-685
ISSN0906-6691
DOIs
Publication statusPublished - 2018

Keywords

  • Artificial lakes
  • Circadian rhythm
  • Cormorant predation
  • Repeatability
  • Telemetry
  • Whitefish

Cite this

@article{66d104385fe2425fb36a2893d50ac3ca,
title = "Evidence of cormorant-induced mortality, disparate migration strategies and repeatable circadian rhythm in the endangered North Sea houting (Coregonus oxyrinchus ): A telemetry study mapping the postspawning migration",
abstract = "Life history theory predicts a trade-off between migration and residency where migration is favoured when it infers elevated fitness. Although migration to more favourable environments offers higher growth rates, migrants often experience increased mortality due to predation. Here, we investigated mortality and migration behaviour of the North Sea houting (Coregonus oxyrinchus), an anadromous salmonid endemic to the Wadden Sea. We used acoustic telemetry to map the migration of the only remaining indigenous population by applying stationary hydrophones combined with manual tracking. Data suggested a total mortality of 26{\%}, with 30{\%} of the total mortality attributed to predation by great cormorants (Phalacrocorax carbo sinensis), highlighting that North Sea houting conservation could be jeopardised by increased cormorant predation. Risk of cormorant predation was size-dependent, with smaller fish suffering higher risk of predation. The study found North Sea houting to exhibit disparate migration strategies and identified a lentic area in the estuary as an important habitat. Two newly established artificial lakes within the river system significantly reduced the migration speeds, possibly indicating constrained navigation through the lakes. The migration into the Wadden Sea correlated with temperature perhaps indicating osmoregulatory constraints of sea entry. Unlike most salmonid species, migration occurred both day and night. Moreover, fish exhibited repeatable individual differences in diel activity patterns, suggesting that individuals differ consistently in their migratory activity throughout the 24-hr period. Our study provides novel information on salmonid migration, which is crucial for the development of science-based conservation strategies.",
keywords = "Artificial lakes, Circadian rhythm, Cormorant predation, Repeatability, Telemetry, Whitefish",
author = "Jensen, {Lasse Fast} and Paul Rognon and Kim Aarestrup and B{\o}ttcher, {Jesper W{\o}hlk} and Cino Pertoldi and Thomsen, {S{\o}ren N{\o}hr} and Morten Hertz and Jacob Winde and Svendsen, {Jon Christian}",
year = "2018",
doi = "10.1111/eff.12383",
language = "English",
volume = "27",
pages = "672--685",
journal = "Ecology of Freshwater Fish",
issn = "0906-6691",
publisher = "Wiley-Blackwell",
number = "3",

}

Evidence of cormorant-induced mortality, disparate migration strategies and repeatable circadian rhythm in the endangered North Sea houting (Coregonus oxyrinchus ): A telemetry study mapping the postspawning migration. / Jensen, Lasse Fast; Rognon, Paul; Aarestrup, Kim; Bøttcher, Jesper Wøhlk; Pertoldi, Cino; Thomsen, Søren Nøhr; Hertz, Morten; Winde, Jacob; Svendsen, Jon Christian.

In: Ecology of Freshwater Fish, Vol. 27, No. 3, 2018, p. 672-685.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Evidence of cormorant-induced mortality, disparate migration strategies and repeatable circadian rhythm in the endangered North Sea houting (Coregonus oxyrinchus ): A telemetry study mapping the postspawning migration

AU - Jensen, Lasse Fast

AU - Rognon, Paul

AU - Aarestrup, Kim

AU - Bøttcher, Jesper Wøhlk

AU - Pertoldi, Cino

AU - Thomsen, Søren Nøhr

AU - Hertz, Morten

AU - Winde, Jacob

AU - Svendsen, Jon Christian

PY - 2018

Y1 - 2018

N2 - Life history theory predicts a trade-off between migration and residency where migration is favoured when it infers elevated fitness. Although migration to more favourable environments offers higher growth rates, migrants often experience increased mortality due to predation. Here, we investigated mortality and migration behaviour of the North Sea houting (Coregonus oxyrinchus), an anadromous salmonid endemic to the Wadden Sea. We used acoustic telemetry to map the migration of the only remaining indigenous population by applying stationary hydrophones combined with manual tracking. Data suggested a total mortality of 26%, with 30% of the total mortality attributed to predation by great cormorants (Phalacrocorax carbo sinensis), highlighting that North Sea houting conservation could be jeopardised by increased cormorant predation. Risk of cormorant predation was size-dependent, with smaller fish suffering higher risk of predation. The study found North Sea houting to exhibit disparate migration strategies and identified a lentic area in the estuary as an important habitat. Two newly established artificial lakes within the river system significantly reduced the migration speeds, possibly indicating constrained navigation through the lakes. The migration into the Wadden Sea correlated with temperature perhaps indicating osmoregulatory constraints of sea entry. Unlike most salmonid species, migration occurred both day and night. Moreover, fish exhibited repeatable individual differences in diel activity patterns, suggesting that individuals differ consistently in their migratory activity throughout the 24-hr period. Our study provides novel information on salmonid migration, which is crucial for the development of science-based conservation strategies.

AB - Life history theory predicts a trade-off between migration and residency where migration is favoured when it infers elevated fitness. Although migration to more favourable environments offers higher growth rates, migrants often experience increased mortality due to predation. Here, we investigated mortality and migration behaviour of the North Sea houting (Coregonus oxyrinchus), an anadromous salmonid endemic to the Wadden Sea. We used acoustic telemetry to map the migration of the only remaining indigenous population by applying stationary hydrophones combined with manual tracking. Data suggested a total mortality of 26%, with 30% of the total mortality attributed to predation by great cormorants (Phalacrocorax carbo sinensis), highlighting that North Sea houting conservation could be jeopardised by increased cormorant predation. Risk of cormorant predation was size-dependent, with smaller fish suffering higher risk of predation. The study found North Sea houting to exhibit disparate migration strategies and identified a lentic area in the estuary as an important habitat. Two newly established artificial lakes within the river system significantly reduced the migration speeds, possibly indicating constrained navigation through the lakes. The migration into the Wadden Sea correlated with temperature perhaps indicating osmoregulatory constraints of sea entry. Unlike most salmonid species, migration occurred both day and night. Moreover, fish exhibited repeatable individual differences in diel activity patterns, suggesting that individuals differ consistently in their migratory activity throughout the 24-hr period. Our study provides novel information on salmonid migration, which is crucial for the development of science-based conservation strategies.

KW - Artificial lakes

KW - Circadian rhythm

KW - Cormorant predation

KW - Repeatability

KW - Telemetry

KW - Whitefish

U2 - 10.1111/eff.12383

DO - 10.1111/eff.12383

M3 - Journal article

VL - 27

SP - 672

EP - 685

JO - Ecology of Freshwater Fish

JF - Ecology of Freshwater Fish

SN - 0906-6691

IS - 3

ER -