Decision bias in marine spatial planning of offshore wind farms: Problems of singular versus cumulative assessments of economic impacts on fisheries

The current approval procedure for wind farm proposals in the German EEZ only considers site specific conflict analysis between the wind farm and fisheries. Due to the relatively small spatial coverage of the sites potential opportunity losses to the fisheries are always considered as low or negligible. Cumulative effects on fisheries that will occur once all proposed wind farms are in place are not yet considered adequately. However, those cumulative effects will be quite substantial because, in particular, opportunities to catch such valuable species as flatfish will be considerably reduced.     

Coral Recruitment and Regeneration on a Maldivian Reef 21 Months after the Coral Bleaching Event of 1998

Abstract. This paper describes the quantitative inventory of stony corals on a Maldivian reef after the bleaching event of 1998. The detailed data, collected in March 1999 and March 2000, comprise survival, new recruitment and regenerates. They were obtained in 6 transects laid out randomly on the reef flat, on 22 Acropora tables on 6 sites at the reef edge and on 39 Porites lobata blocks and 1 Diploastrea heliopora colony. The present cover of living zooxanthellate corals is reduced to ca. 2 – 5 % of its previous state. Acroporidae and Pocilloporidae were practically wiped out, while Poritidae survived partly and Agariciidae (esp. Pavona) are now the dominant group. New settlements on dead Acropora tables were mainly Agariciidae, followed by Acroporidae and Pocilloporidae. Regenerates on Porites were pronounced and the apparent yearly increase in mass was about threefold that of Diploastrea, which is 3 – 4 mm per year. The influence on reef ecology in terms of coral substrate and species, possible sources of larvae, change of guilds in reef builders, other species and the prospect for further development of the reef, with respect to growth versus erosion, is discussed.     

Overlooked small and juvenile piscivores dominate shallow-water estuarine “refuges” in tropical Australia

A model was developed to estimate the relative impacts of different functional groups of piscivores on the shallow-water estuarine nursery assemblage of tropical north-eastern Australia. Data on variability in the occurrence, number and type of fish in the diet of different piscivores was combined with estimates of the abundance of each group. The model predicts that previously overlooked small and occasional or ‘minor’ piscivores, such as sillaginids, ambassids, sparids and small juvenile carangids, inflict mortality on new recruits to shallow-water nursery habitats that is orders of magnitude greater than that imparted by more conspicuous larger piscivores. Because of their high abundance, a shift in the diet of minor piscivores to prey on new recruits results in a massive increase in the consumption of fish prey by the piscivore assemblage as a whole. Even if the evidence that minor piscivores switch to target new recruits was rejected, the model shows that the highly abundant minor piscivores must still exert a significant proportion of predation mortality experienced by recruiting fishes. As a broad functional group, minor piscivores occur in most aquatic systems around the globe and are likely to play an important but largely overlooked role as predators that shape communities through predation on critical early life stages of other fishes.     

Short-term Effects of Intertidal Macroalgal Blooms on the Macrohabitat Selection and Feeding Behaviour of Wading Birds in the Mondego Estuary (West Portugal)

The possible effects of intertidal macroalgal blooms on the feeding distribution and behaviour of the waders in the Mondego Estuary (West Portugal) are discussed in the present paper. The presence of algae over the sediments did not deter the waders absolutely from feeding in a place, but most species did show some tendency to avoid highly eutrophic areas. However, there were no clear signs that the species redistributed themselves within the Estuary as the amount of algae changed, nor did the alternative feeding habitats (the salt pans) seem to be used more when algae were particularly abundant on the mud flats. In one species, bird numbers, rather than the amount of algae present, explained the numbers of birds using the salt pans when the two factors were considered together in a multiple regression analysis. There were no striking differences between algae-free and algae-weeded areas in some aspects of the foraging of two representative species, the scolopacid DunlinCalidris alpinaand the charadriid Grey PloverPluvialis squatarola. The results suggest either: (1) that the presence of algae did not strongly influence the distribution of the feeding waders, at least in the conditions prevailing during the study; or (2) that most waders were able to adapt to feeding on weeded areas; perhaps through subtle and undetected alterations in their feeding behaviour.