External parasites: how anchor worms affect Iberian endemic fish

Lernaea cyprinacea, commonly known as anchor worm, is a cosmopolitan invasive copepod that parasitizes wide variety of freshwater fish, including several native and endemic species the Iberian Peninsula (Sánchez-Hernández 2017), like Squalius alburnoides from Guadiana River basin depicted in photograph, with 3 different individuals attached. Anchor worm was introduced to Iberia Asia 1970s (Simon Vicente et al. 1973). While males are free-living, adult females attach their anchors – modification head fish host, usually fins, gills or mouth. Infestation by this external parasite easily recognised wounds, ulcers inflammatory processes it induces skin muscle (Hossain 2018, see photograph). It may also induce anaemia, malformations, reduced growth increased susceptibility secondary infections 2017). Small specially affected swimming ability, respiration health condition due mechanical compression internal organs, both resulting ulcerous lesions developed at anchoring sites (Guagliardo & Tanzola 2016). Since infestation prevalence hypothesised be positively correlated higher water temperatures (Marcogliese 2001), outbreaks expected increase intermittent southern rivers under global climate change scenario (Macedo-Veiga 2019), which will likely contribute aggravation conservation status already imperilled species. Although broader studies needed, reported prevalences than sympatric alien 2019)