The effects of the ectoparasite Tracheliastes polycolpus (Copepoda: Lernaeopodidae) on the fins of rostrum dace (Leuciscus leuciscus burdigalensis)

Abstract

Rostrum dace (Leuciscus leuciscus burdigalensis) from the River Viaur were found to be infested with the ectoparasite Tracheliastes polycolpus (Copepoda: Lernaeopodidae). Samples from five study sites along the river revealed different patterns of parasite infestation. Heavily infested fish were found at the upper study sites whereas much lower infestation levels were observed at the lower study sites. The copepods showed an aggregated dispersion pattern on host fins. The results showed significantly preferred microhabitats, with adult females being more abundant on the anal, pelvic and along the external part of the pectoral fins. The anal and pelvic fins were damaged by the parasite with a loss of their surface area. These fin alterations may reduce the fish's swimming ability and therefore affect the rostrum dace population. Our findings highlight the need to study the effects of parasites on stream fish populations.

Why do parasitized hosts look different? Resolving the “chicken-egg” dilemma

“…In this species, only the female is parasitic and is anchored to host Wns to feed on the epithelial cells and mucus of the host. This grazing activity characteristically damages the Wns, leading to their destruction (i.e., a direct pathogenic eVect, see Loot et al 2004). In Wsh, Wns are used for stability, agility and propulsion of the body during locomotion and thus play a central role in food capture (Schrank and Webb 1998;Lauder and Drucker 2002).…”

First Records of <i>Tracheliastes sachalinensis</i> (Copepoda: Lernaeopodidae), a Fin Parasite of Cyprinids, from Japan

“…polycolpus (e.g., Loot et al 2004Loot et al , 2011Blanchet et al 2009a, b;Cardon et al 2011;Lootvoet et al 2013;Mazé-Guilmo et al 2014). In contrast to it, almost nothing is known about the host-parasite relationship between Tra.…”

Evidence of morphological discrete units in an endemic fish, the rostrum dace (Leuciscus burdigalensisValenciennes 1844), within a small river basin

“…This might be a problem for the survival of this species. First, rostrum dace is dramatically impacted by parasites (Loot et al, 2004). Then, both the hydroelectric and the numerous hillside dams have dramatically decreased water flow in winter and therefore, increased siltation, especially after their flushing (Dauba, 1994;Salvan, 1996;Guilmet, 1997).…”

“…No sexual dimorphism in the body morphology has been reported in the literature except for pectoral fins, which are longer for males (Spillmann, 1961). However, in this case, the fins were not retained in morphometric analysis since they were degraded by the ectoparasite Tracheliastes polycolpus (Loot et al, 2004). Thus, no further sex determination was undertaken in order to minimise handling and to release the fish in good condition.…”