Long-term trends in juvenile flatfish indicate a dramatic reduction in nursery function of the Balgzand intertidal, Dutch Wadden Sea
van der Veer, H.W.; Koot, J.; Aarts, G.M; Dekker, R.; Diderich, W.; Freitas, V.; Witte, J.IJ. (2011). Long-term trends in juvenile flatfish indicate a dramatic reduction in nursery function of the Balgzand intertidal, Dutch Wadden Sea. Mar. Ecol. Prog. Ser. 434: 143-154. dx.doi.org/10.3354/meps09209
In: Marine Ecology Progress Series. Inter-Research: Oldendorf/Luhe. ISSN 0171-8630; e-ISSN 1616-1599, meer
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| Trefwoorden |
Platichthys flesus (Linnaeus, 1758) [WoRMS]; Pleuronectes platessa Linnaeus, 1758 [WoRMS]
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| Author keywords |
Predation; Plaice; Flounder; Pleuronectes platessa; Platichthys flesus;Wadden Sea; Benthos-fish interaction; Top-down control; Nursery function |
| Auteurs | | Top |
- van der Veer, H.W., meer
- Koot, J.
- Aarts, G.M, meer
- Dekker, R., meer
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| Abstract |
Since 1975, juvenile flatfish (plaice and flounder) populations have been monitored at the Balgzand intertidal and, based on this data series (1975-2007), the interannual patterns in predation pressure were quantified. Temporal patterns in abundance have changed greatly, especially for plaice. Up to the early 1980s, 3 year classes (0-, I- and II-group) were present and growing up in the area, but from the late 1980s onwards, densities of the I- and II-group plaice dropped from a few hundred individuals per 1000 m(2) to levels close to zero. It appears that the Balgzand intertidal has lost its nursery function for I- and II-group plaice, although feeding conditions have remained the same or even slightly increased since the late 1970s. The absence of I- and II-group flatfish in the intertidal cannot be explained at present; however, processes operating offshore are most likely involved. As a consequence, the annual predation pressure by juvenile flatfish upon the intertidal macrozoobenthos dropped by 94%, declining from an average of approximately 5 to 0.25 g ash free dry mass m(-2). Such a decline in top-down predation may not only have directly influenced the macrozoobenthic community, but may also have indirectly affected food availability and accessibility for other top predators (e.g. shorebirds). |
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