Life in the fast lane: Temperature, density and host species impact survival and growth of the fish ectoparasite Argulus foliaceus

Abstract

With expanding human populations, the food sector has faced constant pressure to sustainably expand and meet global production demands. In aquaculture this frequently manifests in an animal welfare crisis, with fish increasingly farmed under high production, high stress conditions. These intense environments can result in fish stocks having a high susceptibility to infection, with parasites and associated disease one of the main factors limiting industry growth. Prediction of infection dynamics is key to preventative treatment and mitigation. Considering the climatic and technology driven changes facing aquaculture, an understanding of how parasites react across a spectrum of conditions is required. Here we assessed the impact of temperature, infection density and host species on the life history traits of Argulus foliaceus, a common palearctic fish louse, representative of a parasite group problematic in freshwater aquaculture and fisheries worldwide. Temperature significantly affected development, growth and survival; parasites hatched and developed faster at higher temperatures, but also experienced shorter lifespans when maintained off the host. At high temperatures, these parasites will likely experience a short generation time as their life history traits are completed more rapidly. A. foliaceus additionally grew faster on natural hosts and at lower infection densities. Ultimately such results contribute to prediction of population dynamics, aiding development of effective control to improve animal welfare and reduce industry loss.

Evaluation of Argulus indicus on striped snakehead (Channa striata) in Towuti Lake, South Sulawesi, Indonesia

“…The severity of infestation with Argulus in a given waterbody will be influenced by the condition of the host as well as the reproductive and recruitment capability of Argulus, both of which will be influenced by many factors, including environmental conditions such as the substrate and water temperature (Alsarakibi et al 2012;Sahoo et al 2013;Alsarakibi et al 2014). In general, Argulus parasites can survive in waters with a wide range of physical and chemical parameters, and some species of Argulus are known to tolerate temperatures as low as 3 o C and as high as 43 o C (Walker et al 2011;Hunt and Cable 2020). Argulosis has frequently been seen as a seasonal disease, especially in subtropical regions.…”

Morphometric and molecular identification ofArgulus japonicus(Thiele 1900) in vulnerable Himalayan snow trout,Schizothorax richardsonii(Gray 1832)

“…In India, A. japonicus is reported from goldfish (Carassius auratus), common carp, (Cyprinus carpio) (Walker, 2008) and Indian major carps, rohu, (Labeo rohita) and Catla, (Catla Catla) (Prabhavathy & Sreenivasan, 1976;Sahoo et al, 2012). Argulus infestation (Muller 1785) could lead to severe economic loss up to 67,102.00 INR (US$ 1428) per ha in freshwater aquaculture in India (Sahoo et al, 2013a(Sahoo et al, ,2013b; Turkey and Japan causing mass mortality (Hunt & Cable, 2020) every year. The symptoms of Argulus infection in fish include haemorrhages, abrasive wounds, ulcers, dermal crates, low feed conversion ratio and anaemia (Gilbert & Avenant-Oldewage, 2018).…”