Population dynamics of two diplectanid species (Monogenea) parasitising sparid hosts (Sparidae)

Abstract

Economically important sparid fish species, gilthead (Sparus aurata) and white seabream (Diplodus sargus) (Sparidae) are frequently parasitised by diplectanid monogeneans, known to induce severe losses in farming conditions. We have analysed population dynamic of two diplectanid species, Lamellodiscus echeneis and Lamellodiscus ignoratus (Monogenea: Diplectanidae) collected from two bream species in the Beymelek Lagoon (southwest coast of Turkey), comparing it between different host variables (fish size, age and sex) in order to have insight in parasites' ecology, important for managing parasitosis in the intensive aquaculture system. In seabream (N = 127), L. echeneis prevalence was 46.5 % (exact 95 % confidence limits 38.90-54.14), mean abundance 5.64 (bootstrap 95 % confidence limits 4.20-7.65) and mean intensity 12.14 (bootstrap 95 % confidence limits 9.49-15.59). In white seabream (N = 102), L. ignoratus prevalence was 24.5 % (exact 95 % confidence limits 16.53-34.03), mean abundance 1.73 (bootstrap 95 % confidence limits 0.98-3.21) and mean intensity 7.04 (bootstrap 95 % confidence limits 4.60-11.40). Parasites' parameters differed only between seasons in both hosts and between age categories in gilthead, but not in white seabream.

Monogenean Sparicotyle chrysophrii: The major pathogen of the Mediterranean gilthead seabream aquaculture

“…Unfortunately, in the latter study, the small fish category encompassed fish over +1 year, meaning that the monogenean infection pattern in fingerlings seeded in cages has not been evaluated. It is interesting to observe that the gilthead seabream diplectanid L. echeneis shows the same pattern of distribution as S. chrysophrii reported earlier 33 ; the highest prevalence in the oldest age category and the highest mean abundance and intensity in the lower age category 71 . This could be attributed to different circumstances; either to a more developed immune system in older fish that rejects a considerable number of parasites, which nevertheless, aggregate over a longer host life span (3–4 yrs), and/or to parasite ability to inhabit a larger gill surface 71,72 .…”

“…It is interesting to observe that the gilthead seabream diplectanid L. echeneis shows the same pattern of distribution as S. chrysophrii reported earlier 33 ; the highest prevalence in the oldest age category and the highest mean abundance and intensity in the lower age category. 71 This could be attributed to different circumstances; either to a more developed immune system in older fish that rejects a considerable number of parasites, which nevertheless, aggregate over a longer host life span (3-4 yrs), and/or to parasite ability to inhabit a larger gill surface. 71,72 Irrespectively of the cause, a welldesigned study of S. chrysophrii distribution in relation to host size/ age category over at least two production cycles should be helpful in the planning of the treatments or other intervention schemes on the farms.…”

What causes the increase in aggregation as a parasite moves up a food chain?

“…Values [20,21,22], and excluding data used in [15]. The data is available in the electronic supplementary material.…”

“…Let P t (z) be the probability generating function of Xt . From equation(22) there exists a c s,t ∈ [0, 1] such that…”

Untitled

“…Studies on the seasonal dynamics of populations and community structure of parasites have been conducted for several decades with many important findings (Køie, 1988;Nie and Kennedy, 1991;Boungou et al, 2008;Luo et al, 2010, Emre et al, 2015. Many of them concerned the population dynamics of congeneric species of monogeneans on the same species of host (Simková et al, 2000;Matejusová et al, 2003;Boungou et al, 2008), but only a few such studies have focused on the community dynamics of congeneric species (Knipes and Janovy, 2009;Muñoz and Randhawa, 2011) and none involved monogeneans on farmed Japanese eels.…”