| Autor: |
Baptist, M.J., van Bemmelen, R.S.A., Leopold, M.F., Couperus, A.S., de Haan, D., Tribuhl, S.V., Dijkman, E.M. |
| Jazyk: |
angličtina |
| Rok vydání: |
2010 |
| Předmět: |
|
| Popis: |
We surveyed the Frisian Front area in the southern North Sea (4.0-5.5 E 53.4-54.3 N) to determine the distribution of piscivorous seabirds and subsurface pelagic fish during daylight hours. Bird observations were carried out following the one-sided ESAS-protocol. Subsurface pelagic fish distribution was determined by a combination of innovative fishing nets and acoustic sonar. We developed and deployed a surface trawl to fish the upper three metres of the water column. We applied a second surface trawl with a fixed opening of 2.5 metres, equipped with a plankton bottle to determine the distribution of fish larvae and zooplankton. We built and deployed an upside-down towed acoustic sonar to investigate the distribution of fish in the upper five metres of the water column. Results show a correlation between distribution of subsurface pelagic fish and environmental parameters. Overall, we found a very low density of small epipelagic fish suitable as prey for piscivorous seabirds. Prey density was too low to support the number of Lesser Black-backed Gulls in the area. These species seemed to rather forage on the discards from fishing vessels. Common Guillemots were present in relative high numbers, and their distribution did not correlate with the distribution of their prey. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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