Abstract
Abstract Following an 85% decline in global oyster populations, there has been a recent resurgence in interest in the restoration of the European native oyster Ostrea edulis. Motivations for restoration from environmental stakeholders most often include recovering lost habitats and associated biodiversity and supporting ecosystem function. In coastal communities, another important justification is recovery of traditional and low‐impact fisheries but this has received less attention. Many restoration projects across Europe focus on the translocation of adult stocks, under the assumption that the limit to population growth and recovery is adult growth and survival. This may not necessarily be the case, especially where knowledge of large extant adult populations exists as in the Blackwater, Crouch, Roach and Colne Marine Conservation Zone in Essex, UK. Identifying what limits population growth for restoration and recovery is an important conservation tool. Here, the first size‐dependent survival, growth and fecundity data for free‐living O. edulis from a novel field experiment are used to parameterize an Integral Projection Model that examines the sensitivity of a flat oyster population to variation in individual vital rates and to potential harvesting – an original objective of a coastal community‐led restoration project. Given the high adult fecundity in this species, population recovery is most sensitive to changes in recruitment success; however, elasticity (proportional sensitivity of the population) is more evenly spread across other parameters when recruitment is already high. Based on locally agreed management objectives, recovery to double the current stock biomass should take 16–66 years (mean = 30 years) without active intervention. At that point, harvest rates could be sustained below 5% of the harvestable adult size whilst ensuring λs remains above 1.
Highlights
Once a common species around all coastlines of the UK and widespread throughout Europe, the European native oyster, Ostrea edulis, has been reduced to a few remaining strongholds, with oyster populations of all species thought to have declined by as much as 85% worldwide (Beck et al, 2011)
Many European native oyster restoration projects are directed towards the translocation of adult stock, with population status largely assessed via estimated abundance or biomass of adults (Marine Management Organisation, 2019)
If current estimates of growth, survival, fecundity and recruitment are accurate and do not improve further in the absence of active intervention recovery of the BCRC MCZ, the native oyster population is estimated to recover in 16–66 years with a mean of 30 years
Summary
Once a common species around all coastlines of the UK and widespread throughout Europe, the European native oyster, Ostrea edulis, has been reduced to a few remaining strongholds, with oyster populations of all species thought to have declined by as much as 85% worldwide (Beck et al, 2011). Many European native oyster restoration projects are directed towards the translocation of adult stock (i.e. the movement of oysters from coastal areas of high/higher abundance to areas of low abundance), with population status largely assessed via estimated abundance or biomass of adults (Marine Management Organisation, 2019). It is good conservation practice to a priori examine what life history stages are most likely to respond to restoration or management interventions, and affect population growth (Montero‐Serra et al, 2018) Such comprehensive assessments of population status and sensitivity require real‐time measurements of demographic parameters such as size structure, growth, survival and fecundity of individuals in the population (Caswell, 1989; Ellner & Rees, 2006; Merow et al, 2014). Increasing spat settlement and survival via manipulation of habitat may be a more appropriate restoration tool than translocating adult oysters, or halting their fishing in a given area
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
