Low energy values of fish as a probable cause of a major seabird breeding failure in the North Sea

S Wanless, M P Harris, P Redman, J R Speakman

Research output: Contribution to journalArticle

235 Citations (Scopus)

Abstract

Many seabirds in the North Sea feed on lesser sandeels Ammodytes marinus during the breeding season. Unprecedented breeding failures were recorded at many seabird colonies on the east coast of Britain in 2004, We used demographic, dietary and behavioural data from a long-term study of a colony of common guillemots Uria aalge, the most abundant seabird species in the North Sea, to set the 2004 season in context. Birds at this colony showed greatly reduced breeding success and those chicks that did survive left the colony in very poor condition. The main prey item fed to chicks in 2004 was sprat Sprattus sprattus rather than sandeels, and parents increased the amount of time spent foraging, frequently leaving chicks unattended in order to maintain a normal feeding rate. The calculated daily food intake of chicks derived from these values did not differ markedly from previous years and therefore the magnitude of the impact on chick growth and breeding success appeared disproportionately large. However, nutrient analyses of fish collected from birds in 2004 revealed them to be of significantly lower energy value than expected. Poor food quality therefore appeared to be the proximate cause of seabird breeding failure in 2004 giving support to the 'junk-food' hypothesis. Single-prey loaders such as guillemots will be particularly sensitive to reductions in the energy value of food items. The reasons for the poor fish condition in this part of the North Sea are currently unknown, but the results provide further evidence of major changes in the North Sea food web.

Original languageEnglish
Pages (from-to)18
Number of pages8
JournalMarine Ecology Progress Series
Volume294
Publication statusPublished - 2005

Keywords

  • breeding failure
  • energy value
  • lesser sandeel
  • sprat
  • food intake
  • predator-prey interactions
  • common guillemot
  • junk food hypothesis
  • GUILLEMOTS URIA-AALGE
  • ISLE-OF-MAY
  • COMMON MURRES
  • PIGEON GUILLEMOTS
  • AMMODYTES-MARINUS
  • YOUNG GUILLEMOTS
  • PREY ABUNDANCE
  • CLIMATE-CHANGE
  • FORAGE FISHES
  • DENSITY

Cite this

Low energy values of fish as a probable cause of a major seabird breeding failure in the North Sea. / Wanless, S ; Harris, M P ; Redman, P ; Speakman, J R .

In: Marine Ecology Progress Series, Vol. 294, 2005, p. 18.

Research output: Contribution to journalArticle

@article{25bc33c5df624a7c9c02ccc12d494547,
title = "Low energy values of fish as a probable cause of a major seabird breeding failure in the North Sea",
abstract = "Many seabirds in the North Sea feed on lesser sandeels Ammodytes marinus during the breeding season. Unprecedented breeding failures were recorded at many seabird colonies on the east coast of Britain in 2004, We used demographic, dietary and behavioural data from a long-term study of a colony of common guillemots Uria aalge, the most abundant seabird species in the North Sea, to set the 2004 season in context. Birds at this colony showed greatly reduced breeding success and those chicks that did survive left the colony in very poor condition. The main prey item fed to chicks in 2004 was sprat Sprattus sprattus rather than sandeels, and parents increased the amount of time spent foraging, frequently leaving chicks unattended in order to maintain a normal feeding rate. The calculated daily food intake of chicks derived from these values did not differ markedly from previous years and therefore the magnitude of the impact on chick growth and breeding success appeared disproportionately large. However, nutrient analyses of fish collected from birds in 2004 revealed them to be of significantly lower energy value than expected. Poor food quality therefore appeared to be the proximate cause of seabird breeding failure in 2004 giving support to the 'junk-food' hypothesis. Single-prey loaders such as guillemots will be particularly sensitive to reductions in the energy value of food items. The reasons for the poor fish condition in this part of the North Sea are currently unknown, but the results provide further evidence of major changes in the North Sea food web.",
keywords = "breeding failure, energy value, lesser sandeel, sprat, food intake, predator-prey interactions, common guillemot, junk food hypothesis, GUILLEMOTS URIA-AALGE, ISLE-OF-MAY, COMMON MURRES, PIGEON GUILLEMOTS, AMMODYTES-MARINUS, YOUNG GUILLEMOTS, PREY ABUNDANCE, CLIMATE-CHANGE, FORAGE FISHES, DENSITY",
author = "S Wanless and Harris, {M P} and P Redman and Speakman, {J R}",
year = "2005",
language = "English",
volume = "294",
pages = "18",
journal = "Marine Ecology Progress Series",
issn = "0171-8630",
publisher = "Inter-Research",

}

TY - JOUR

T1 - Low energy values of fish as a probable cause of a major seabird breeding failure in the North Sea

AU - Wanless, S

AU - Harris, M P

AU - Redman, P

AU - Speakman, J R

PY - 2005

Y1 - 2005

N2 - Many seabirds in the North Sea feed on lesser sandeels Ammodytes marinus during the breeding season. Unprecedented breeding failures were recorded at many seabird colonies on the east coast of Britain in 2004, We used demographic, dietary and behavioural data from a long-term study of a colony of common guillemots Uria aalge, the most abundant seabird species in the North Sea, to set the 2004 season in context. Birds at this colony showed greatly reduced breeding success and those chicks that did survive left the colony in very poor condition. The main prey item fed to chicks in 2004 was sprat Sprattus sprattus rather than sandeels, and parents increased the amount of time spent foraging, frequently leaving chicks unattended in order to maintain a normal feeding rate. The calculated daily food intake of chicks derived from these values did not differ markedly from previous years and therefore the magnitude of the impact on chick growth and breeding success appeared disproportionately large. However, nutrient analyses of fish collected from birds in 2004 revealed them to be of significantly lower energy value than expected. Poor food quality therefore appeared to be the proximate cause of seabird breeding failure in 2004 giving support to the 'junk-food' hypothesis. Single-prey loaders such as guillemots will be particularly sensitive to reductions in the energy value of food items. The reasons for the poor fish condition in this part of the North Sea are currently unknown, but the results provide further evidence of major changes in the North Sea food web.

AB - Many seabirds in the North Sea feed on lesser sandeels Ammodytes marinus during the breeding season. Unprecedented breeding failures were recorded at many seabird colonies on the east coast of Britain in 2004, We used demographic, dietary and behavioural data from a long-term study of a colony of common guillemots Uria aalge, the most abundant seabird species in the North Sea, to set the 2004 season in context. Birds at this colony showed greatly reduced breeding success and those chicks that did survive left the colony in very poor condition. The main prey item fed to chicks in 2004 was sprat Sprattus sprattus rather than sandeels, and parents increased the amount of time spent foraging, frequently leaving chicks unattended in order to maintain a normal feeding rate. The calculated daily food intake of chicks derived from these values did not differ markedly from previous years and therefore the magnitude of the impact on chick growth and breeding success appeared disproportionately large. However, nutrient analyses of fish collected from birds in 2004 revealed them to be of significantly lower energy value than expected. Poor food quality therefore appeared to be the proximate cause of seabird breeding failure in 2004 giving support to the 'junk-food' hypothesis. Single-prey loaders such as guillemots will be particularly sensitive to reductions in the energy value of food items. The reasons for the poor fish condition in this part of the North Sea are currently unknown, but the results provide further evidence of major changes in the North Sea food web.

KW - breeding failure

KW - energy value

KW - lesser sandeel

KW - sprat

KW - food intake

KW - predator-prey interactions

KW - common guillemot

KW - junk food hypothesis

KW - GUILLEMOTS URIA-AALGE

KW - ISLE-OF-MAY

KW - COMMON MURRES

KW - PIGEON GUILLEMOTS

KW - AMMODYTES-MARINUS

KW - YOUNG GUILLEMOTS

KW - PREY ABUNDANCE

KW - CLIMATE-CHANGE

KW - FORAGE FISHES

KW - DENSITY

M3 - Article

VL - 294

SP - 18

JO - Marine Ecology Progress Series

JF - Marine Ecology Progress Series

SN - 0171-8630

ER -