Environmentally Driven Ecological Fluctuations on the Faroe Shelf Revealed by Fish Juvenile Surveys
| Autor: | Sólveig Rósa Ólafsdóttir, Helga Bára Mohr Vang, Meinhard Poulsen, Eilif Gaard, Petur Steingrund, Jákup Reinert, Hjálmar Hátún, Sólvá Jacobsen, Karin Margretha H. Larsen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
zooplankton 010504 meteorology & atmospheric sciences lcsh:QH1-199.5 Ocean Engineering Faroe shelf lcsh:General. Including nature conservation geographical distribution Aquatic Science Fish stock Oceanography 01 natural sciences Zooplankton survival Abundance (ecology) 0-group fish lcsh:Science 0105 earth and related environmental sciences Water Science and Technology Biomass (ecology) Global and Planetary Change biology silicate Ecology 010604 marine biology & hydrobiology fungi Pelagic zone Haddock Juvenile fish biology.organism_classification Ecological indicator lcsh:Q primary production |
| Zdroj: | Frontiers in Marine Science, Vol 6 (2019) |
| ISSN: | 2296-7745 |
| DOI: | 10.3389/fmars.2019.00559 |
| Popis: | Comprehensive late June surveys have for decades been carried out on the Faroe shelf in order to estimate the abundance of juvenile fish – the 0-group. The abundance of cod juveniles has previously been used in recruitment studies, while the ecological implication of the 0-groups has hitherto received less attention. Here we examined the pelagic 0-group stage in four of the main fish species on the Faroe shelf: cod, haddock, Norway pout and sandeel, representing more than 90% of all juvenile fish on the shelf. A positive relationship between length and abundance at the 0-group stage is observed for all juveniles, and the inter-annual variability was highly similar among the four fish species. Based on this knowledge, we produced a new ecological indicator for the central Faroe shelf ecosystem – the 0-group length index. The 0-group length index is characterized by marked peaks in 1984, 1987, 1994, 2000, 2009, and 2017, which appear to be related to the shelf primary production from spring to mid-summer, and possibly to the marine climate surrounding the Faroe shelf. There is a better temporal overlap between the fish larvae and their prey (i.e., small- to medium sized zooplankton) in years with an early and intensive bloom, while late and/or weak blooms lead to unfavorable feeding conditions. We furthermore show that a large abundance of 0-group fish has the potential to graze down and thus regulate the biomass of large-sized zooplankton during late June. In addition to this top-down influence the 0-group fish clearly impact commercial fish stocks and seabird colonies, and our 0-group length index is therefore a key ecological indicator for the state of the entire central Faroe shelf ecosystem. |
| Databáze: | OpenAIRE |
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