Development and distribution of the non-indigenous Pacific oyster (Crassostrea gigas) in the Dutch Wadden Sea

Pacific oysters (Crassostrea gigas) were first observed in the Dutch Wadden Sea near Texel in 1983. The population increased slowly in the beginning but grew exponentially from the mid-1990s onwards, although now some stabilisation seems to be occurring. They occur on a variety of substrates such as mussel beds (Mytilus edulis), shell banks, dikes and poles. After initial settlement spat may fall on older individuals and congregate to dense clumps and subsequently form reefs. Individual Pacific oysters grow 3–4 cm long in their first year and 2–3 cm in their second year. Many mussel beds (Mytilus edulis) are slowly taken over by Pacific oysters, but there are also several reports of mussel spat settling on Pacific oyster reefs. This might in the end result in combined reefs. Successful Pacific oyster spat fall seems to be related to high summer temperatures, but also after mild summers much spat can be found on old (Pacific oyster) shells. Predation is of limited importance. Mortality factors are unknown, but every now and then unexplained mass mortality occurs. The gradual spread of the Pacific oyster in the Dutch Wadden Sea is documented in the first instance based on historical and anecdotal information. At the start of the more in-depth investigation in 2002, Pacific oysters of all size classes were already present near Texel. Near Ameland the development could be followed from the first observed settlement. On dense reefs each square metre may contain more than 500 adult Pacific oysters, weighing more than 100 kg per m² fresh weigh

MEMO: Gemeenschapsanalyse bodemschaafgegevens 2009-2012 en boxcorermonsters 2009–2011 in de Zeeuwse banken

Occupational Therapists (OTs) who recommend housing adaptations for people with disabilities, funded through public finance, must satisfy professional codes of practice and the employing local authority requirement to allocate finite resources effectively and fairly. At the same time they must also meet service user expectations. Ethical reasoning will be required to balance these demands whilst practising to a personally acceptable professional standard. This study investigates how OTs understand themselves to develop a sense of fairness and how they use their community of practice in developing professional ethical practice. This was a 2 part methodology. Firstly, OTs from 2 community services were invited to participate in small discussion groups. 3 group sessions, of different sizes ranging from 2-6 participants and duration of 2-3 hours, were recorded in which OTs discussed cases which posed ethical challenges with respect to fairness. All participants were female. Secondly, 4 individual interviews with volunteers from the groups were recorded to collect OT narratives of personal ethical development. Transcripts were analysed using a literary-critical approach focussing for transcripts of group sessions on dialogue in community of practice and ethical approaches used; focussing for interview transcripts on the process of ethical development. OTs were shown developing professional practice dialogically within their own community of practice groups. This finding confirms the importance for professional development of encouraging opportunities for dialogical interaction between OTs. Practical reasoning about justice as theorised by Sen (2009) better characterised OT ethical reasoning practices than biomedical-ethical approach applying universal, abstract ethical principles. OT narratives of ethical development fitted the Aristotelian model of growth in virtue as a whole, across both professional and personal aspects of life. Empathy was tentatively categorised as a virtue rather than a technical skill in this context. Empathy contributed to OT clinical reasoning processes as well as ethical reasoning.<br/

Kuilen en Schieten in het Schelde-estuarium. Vergelijkend vissen op de Zeeschelde in Belgie en Westerschelde in Nederland

In de Westerschelde, het Nederlands gedeelte van het Schelde-estuarium, wordt de visgemeenschap bemonsterd door middel van een ankerkuil terwijl er in het Belgisch gedeelte, de Zeeschelde, met schietfuiken wordt gemonsterd. In het belang van eenheid in een grensoverschrijdende bemonstering van het gehele overgangsgebied van de riviermonding van de Schelde, werd voor 2011 een monitoringscampagne uitgevoerd waarbij op vier locaties de beide methodes gelijktijdig en dicht bij elkaar werden uitgevoerd. De centrale vraag in dit onderzoek was of de toegepaste methoden van ankerkuil en schietfuik op beide delen van de Schelde toepasbaar zijn en vergelijkbare resultaten opleveren