Northern Europe's suitability for offshore European flat oyster (Ostrea edulis) habitat restoration: A mechanistic niche modelling approach

Abstract

1. After centuries of overexploitation, European flat oyster (Ostrea edulis) habitats are increasingly being protected and large-scale oyster habitat restoration projects have been initiated in the North Sea, the English Channel, the Irish Sea and the north-eastern Atlantic.2. Understanding the habitat requirements of flat oysters is key in the selection process of restoration sites.3. In this study, a theoretical niche for all life stages of the flat oyster is determined using a dynamic energy budget model forced with temperature, chlorophyll a and salinity in combination with sediment composition. The suitability of Northern Europe's marine environment for flat oysters is evaluated by applying the proposed niche model on a spatial scale and evaluating spatio-temporal variability in life history traits and metabolic characteristics, such as fitness, reproductive output, settlement success and growth.4. Results show that habitat suitability is limited by low maximum summer temperature and low food availability at higher latitudes and in areas under strong influence of the Atlantic Ocean. Restoration efforts in Ireland and Scotland should be confined to protected and shallow coastal environments. Suitability in the southern North Sea is patchy and mainly depends on seabed substrate. The nearshore areas of the English Channel are highly suitable.5. The georeferenced dataset shared in this study will be useful for restoration practitioners.

Defining operational objectives for nature-inclusive marine infrastructure to achieve system-scale impact

“…Wind farm locations relatively suitable for oyster reef development have been appointed based upon habitat suitability, larval retention, food availability, and historical presence (Smaal et al, 2017;Kamermans et al, 2018a, b;Herman and Van Rees, 2022;Van Duren et al, 2022;Stechele et al, 2023bStechele et al, , 2023. The most important characteristics of habitat suitability relate to the presence of a stable seabed, meaning little seabed mobility (sand waves), low bed shear stress, and a composition that provides a consolidated foundation, such as stable sands, stiff muds, shells or rock (Heŕal and Deslous-Paoli, 1991;Houziaux et al, 2008;Smaal et al, 2017;Hughes et al, 2023).…”

“…Food availability is related to the stratification of the North Sea during the summer season, reducing the transport of the main food source phytoplankton to the seabed. Areas with high seasonal stratification are therefore assumed less suitable for oyster reef development, opposed to areas that are nearly fully mixed (Van Leeuwen et al, 2015;Kamermans et al, 2018a;Stechele et al, 2023b). For estimating the historical presence of oyster reefs, data was used from Olsen (1883), Houziaux et al (2008), andBennema et al (2020).…”

“…The area is partly overlapping with the historic presence of oyster beds (Olsen, 1883;Houziaux et al, 2008;Bennema et al, 2020). The highest potential to establish oyster reefs successfully is generally thought to be in an area with both suitable environmental conditions and historic presence of oyster reefs (Kamermans et al, 2018a, b;Stechele et al, 2023b). Therefore, the area around 54°latitude and between 4°and 6°longitude could be appointed to initiate oyster reef development in the Dutch part of the North Sea (see Figure 3).…”

The world was our oyster: Records reveal the vast historical extent of European oyster reef ecosystems

“…In addition to directly supporting restoration science (e.g. Stechele et al 2023), a historical evidence base for native oyster will be of considerable importance for encouraging the reconsideration of policy decisions based upon a significantly shifted environmental baseline (European Commission 2022;McAfee et al 2022).…”