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In the Baltic Sea, the mesopredator three-spined stickleback (Gasterosteus aculeatus) spends a large part of its life cycle in the open sea, but reproduces in shallow coastal habitats. In coastal waters, it may occur in high abundances, is a potent predator on eggs and larvae of fish, and has been shown to induce trophic cascades with resulting eutrophication symptoms through regulation of invertebrate grazers. Despite its potential significance for the coastal food web, little is known about its life history and population ecology. This paper provides a description of life history traits, migration patterns and spatiotemporal development of the species in the Baltic Sea during the past decades, and tests the hypothesis that stickleback may have a negative impact on populations of coastal predatory fish. Offshore and coastal data during the last 30 years show that stickleback has increased fourfold in the Bothnian Sea, 45-fold in the Central Baltic Sea and sevenfold in the Southern Baltic Sea. The abundances are similar in the two northern basins, and two orders of magnitude lower in the Southern Baltic Sea. The coastward spawning migration of sticklebacks from offshore areas peaks in early May, with most spawners being two years of age at a mean length of 65 mm. The early juvenile stage is spent at the coast, whereafter sticklebacks perform a seaward feeding migration in early autumn at a size of around 35 mm. A negative spatial relation between the abundance of stickleback and early life stages of perch and pike at coastal spawning areas was observed in spatial survey data, indicating strong interactions between the species. A negative temporal relationship was observed also between adult perch and stickleback in coastal fish monitoring programmes supporting the hypothesis that stickleback may have negative population level effects on coastal fish predators. The recent increase in stickleback populations in different basins of the Baltic Sea in combination with negative spatiotemporal patterns and previously observed interactions between stickleback and coastal predatory fish suggests that this species may have gained a key role in the coastal food webs of the Baltic Sea. Through its migrations, stickleback may also constitute an important vector linking coastal and open sea ecosystem dynamics. (c) 2015 Elsevier Ltd. All rights reserved.

The topic of this paper is the modelling of suspended particulate matter (SPM) patterns and their variation on North Sea scale over the time scale of several months. The modelling results are assessed by a formalized comparison with concentrations derived from NOAA/AVHRR reflectance imagery. The nature of the study is a sensitivity analysis of the various modules forming the integrated SPM model: the hydrodynamic model, the wave model and the SPM transport and erosion-sedimentation model. A Goodness-of-Fit criterion is introduced as a single parameter to quantify the difference between SPM model results and data. Its specification reflects the aim of the model, which in this study is the representation of the seasonal behaviour of SPM patterns, and the determination of the sensitivity to uncertainties in model parameters of the transport model, its inputs and forcing or boundary conditions. This Goodness-of-Fit method is applied to a North Sea wide scale SPM model application in both 2-D and 3-D using a curvilinear grid schematization. Results are presented for the period March-September 1994. The results confirm the suitability of NOAA/AVHRR based data to assess the modelling and the importance of the net volume flux which is input to the SPM model. The uncertainties in the present estimates of inputs from e.g. erosion and dumping, and the erosion-sedimentation model parameters are shown to also have a major impact on the modelling results. The approach using the Goodness-of-Fit criterion as such is shown to lead to an objective and reproducible quantification of the model quality. © 2001 Academic Press.

Saltmarshes are important coastal fringe ecosystems supporting a myriad of coastal uses and users. However, saltmarshes have undergone a significant period of global decline, losing 25%–50% of their coverage due to a range of drivers, but mainly as a result of anthropogenic pressures and land-use change. While the value of these coastal systems to society is recognised, global data are fragmented, patchy, and often restricted to local case studies. There is currently no comprehensive understanding of the global variation of ecosystem services, benefits and management practices available. This pioneering study addresses this by investigating the socio-ecological dimension of global variation in ecosystem service provision, and how this is being managed by and for different saltmarsh users. Through a global online questionnaire survey (n = 438) targeting professional saltmarsh researchers and practitioners representing 40 countries across 5 continents, this paper presents an overview of saltmarsh ecosystem services, key drivers influencing management and the variation in factors that influence them. Analysis indicates considerable variation, with geographical location (‘continent’) being the most common moderator, influencing perceptions of saltmarshes, the prioritisation of ecosystem services and management perceptions. Finally, the paper presents a series of recommendations, including the development of an interdisciplinary, international research programme to support restoration and conservation of saltmarshes worldwide.