Ostrea edulis the “native oyster” in Strangford Lough Northern Ireland: Population dynamics and species management recommendations 2021-22
Smyth, D. (2022). Ostrea edulis the “native oyster” in Strangford Lough Northern Ireland: Population dynamics and species management recommendations 2021-22. Bangor University/Ulster Wildlife/Department of Agriculture, Environment and Rural Affairs: [s.l.]. 67 pp.
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| Abstract |
Strangford Lough has supported prolific populations of the “Native Oyster” Ostrea edulis since the Mesolithic through to the mid-1800s however, intense overexploitation rendered the species biologically extinct by the 1900s. The oyster remained largely absent from the lough until the late 1990s when a spawning release from a commercial stock seeded the north andeastern lower intertidal. Within five years the native oyster population had increased from a few thousand to more than 1.2 million. This inadvertent restoration of O. edulis in Strangford Lough is considered by many working in the field as the most successful one-off spawning andsettlement event within the species’ natural range and indeed is the envy of restoration managers throughout Europe and the UK. Even though the Lough’s population has been greatly reduced it is still the topic of greatscientific significance. The Lough’s predominantly intertidal population is regarded as unique for the species, and the three-dimensional multiple native oyster attachments recorded at Newtownards Sailing Club represented the first documented live O. edulis reef formations in modern days. Unfortunately, the history of the native oyster’s demise continually repeats itself in Strangford Lough with numbers gradually decreasing over the past 15 years. However, the two consecutive high temperature summers in 2018 and 2019 offered the prospect of large multiple larval spawns from the remaining oysters in the Lough. As O. edulis offers a substantial suite of ecosystem services and is also subject to a UK Biodiversity Species Action Plan and a target species in carbon capture projects, it was thought appropriate by Ulster Wildlife Trust and DAERA to undertake a comprehensive population survey to ascertain its current status within the Lough. The survey would investigate population dynamics and compare the findings to baseline data from 2004, while also suggesting species augmentation and management measures. |
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