Parasite communities in a marine fish indicate ecological recovery from the impacts of the Prestige oil-spill 12–13 years after the disaster

The Prestige oil-spill (2002) is one of the major marine accidents resulting in contamination of virtually all types of marine habitat along c.900 km of coastline in the North-East Atlantic. Environmental pollution affects parasite populations and communities, both directly and through effects on intermediate and definitive hosts. However, the effects of oil-spills on shelf benthic communities are poorly known. This study addressed the hypothesis of recovery of parasite communities in a marine sparid teleost, the bogue Boops boops (L.) (Teleostei: Sparidae), as indicators of environmental pollution and its effects on benthic/pelagic invertebrate communities in an impacted area off the Galician coast, Spain, 12–13 years after the Prestige oil-spill. Novel data for the metazoan parasite communities collected during 2014–2015 were analysed in association with two unique datasets, one comprising baseline data collected in 2001, one year before the Prestige oil-spill, and one comprising data collected 3–4 years post-spill (2005–2006). Using the taxonomically consistent data on parasites in a series of fish seasonal samples, we found significant differences between the two seasonal post-spill datasets taken at a 9-year time interval (3–4 years and 12–13 years post-spill) in most community metrics and infection parameters of the common species. This was in sharp contrast with the few differences between the long-term post-spill dataset of 2014–2015 and the pre-spill dataset of 2001. Multivariate community similarity analyses confirmed that these differences reflected in the substantial differentiation of parasite community composition and structure of the post-spill communities and the significant homogenisation of communities sampled 12–13 years post-spill and baseline communities. Overall, the novel analyses demonstrated a long-term directional trend in parasite community succession towards ecological recovery irrespective of the natural seasonal variability. These findings suggest longer-term oil-spill impacts on shelf benthic/pelagic invertebrate communities lasting over 10 years.