English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The decline of the European oyster  Ostrea edulis  across its biogeographic range has been driven largely by over-fishing and anthropogenic habitat destruction, often to the point of functional extinction. However, other negatively interacting factors attributing to this catastrophic decline include disease, invasive species and pollution. In addition, a relatively complex life history characterized by sporadic spawning renders  O. edulis  biologically vulnerable to overexploitation. As a viviparous species, successful reproduction in  O. edulis  populations is density dependent to a greater degree than broadcast spawning oviparous species such as the Pacific oyster  Crassostrea  ( Magallana )  gigas . Here, we report on the benthic assemblage of  O. edulis  and the invasive gastropod  Crepidula fornicata  across three actively managed South coast harbors in one of the few remaining  O. edulis  fisheries in the UK. Long-term data reveals that numbers of  O. edulis  sampled within Chichester Harbour have decreased by 96%, in contrast numbers of  C. fornicata  sampled have increased by 441% over a 19-year period. The recent survey data also recorded extremely low densities of  O. edulis,  and extremely high densities of  C. fornicata , within Portsmouth and Langstone Harbours. The native oyster’s failure to recover, despite fishery closures, suggests competitive exclusion by  C. fornicata  is preventing recovery of  O. edulis , which is thought to be due to a lack of habitat heterogeneity or suitable settlement substrate. Large scale population data reveals that mean  O. edulis  shell length and width has decreased significantly across all years and site groups from 2015 to 2017, with a narrowing demographic structure. An absence of juveniles and lack of multiple cohorts in the remaining population suggests that the limited fishing effort exceeds biological output and recruitment is poor. In the Langstone & Chichester 2017 sample 98% of the population is assigned to a single cohort (modal mean 71.20 ± 8.78 mm, maximum length). There is evidence of small scale (<5 km) geographic population structure between connected harbors; the 2015 Portsmouth and Chichester fishery populations exhibited disparity in the most frequent size class with 36% within 81–90 mm and 33.86% within 61–70 mm, respectively, the data also indicates a narrowing demographic over a short period of time. The prevalence of the disease Bonamiosis was monitored and supports this microgeographic population structure. Infection rates of  O. edulis  by  Bonamia ostreae  was 0% in Portsmouth Harbor ( n  = 48), 4.1% in Langstone ( n  = 145) and 21.3% in Chichester ( n  = 48) populations. These data collectively indicate that  O. edulis  is on the brink of an ecological collapse within the Solent harbors. Without effective intervention to mitigate the benthic dominance by  C. fornicata  in the form of biologically relevant fishery policy and the management of suitable recruitment substrate these native oyster populations could be lost.

Active management is required to turn the tide for depletedOstrea edulisstocks from the effects of overfishing, disease and invasive species