Seasonal population dynamics of the monogeneans Pseudorhabdosynochus coioidesis and P. serrani on wild versus cultured groupers in Daya Bay, South China Sea

Abstract

SummaryIn this paper, seasonal samples of wild versus cultured groupers, Epinephelus spp., from Daya Bay, South China Sea were examined to survey the seasonality of two important species, Pseudorhabdosynochus coioidesis and P. serrani (Monogenea: Diplectanidae), and to analyze the interspecific relationships between these two parasites. Between April 2008 and January 2009, P. coioidesis and P. serrani were found to be parasitic only on E. coioides Hamilton during summer and winter in the natural waters of Daya Bay, exhibiting a high degree of host specificity, whereas they co-occurred and persisted on several species of hosts, such as E. coioides, E. bruneus Block and E. awoara Temminck & Schlegel, in an experimental polyculture pond during several seasons. E. coioides is the main host for both of these two monogenean species. The overall prevalences and mean intensities of these two parasites on polycultured Epinephelus spp. showed the same pattern of seasonal fluctuations, with the maximum values during autumn, except for the overall prevalence of P. serrani, which reached its maximum values during summer and winter and the minimum values during spring and autumn. Prevalence and mean intensity were found to be related to host size. In the wild, medium-sized fishes harboured higher infections, whereas under cultured conditions the small-sized and large-sized fishes were more heavily infected. Simultaneous infections of P. coioidesis and P. serrani were common, and there was a significant positive interspecific correlation between these two parasites.

First record of Amphipolycotyle chloroscombrus Hargis, 1957 (Monogenea, Polyopisthocotylea, Gastrocotylidae) in the South Atlantic Ocean

“…According to ROHDE (2005), large hosts represent potential habitats with greater resources for parasites than smaller ones, thus being able to support high rates of infestation. Moreover, environmental factors such as temperature and salinity which influence the reproduction of the monogeneans also affect their abundance and occurrence in some areas during the year (ERNST et al, 2005;LUO;YANG, 2010;KHIDR et al, 2012). Therefore, the low prevalence of A. chloroscombrus on C. chrysurus must be attributed to the reproductive cycle of the parasite and/or the influences of environmental factors, as has also been reported by MUÑOZ and RANDAHAWA (2011) and ÖZER and KIRCA (2013) ( Table 2).…”

Huffmanela plectropomi n. sp. (Nematoda: Trichosomoididae: Huffmanelinae) from the coralgrouper Plectropomus leopardus (Lacépède) off New Caledonia

“…Luo & Yang, 2010). Huffmanela infections could probably endanger cultured fish; however, the life-cycle of Huffmanela spp.…”

Molecular and morphological evidence for the widespread distribution of Laticola paralatesi infecting wild and farmed Lates calcarifer in Australia

“…The observed species diversity could potentially be a consequence of hostswitching events and/or co-evolution within discrete L. calcarifer populations (Kearn 1968, Poulin 2002, Zię tara & Lumme 2002. Host switching may have occurred in Pseudorhabdosynochus coioidesis and P. serrani, which can parasitise closely related grouper species, including Epinephelus coioides, E. bruneus and E. awoara (Luo & Yang 2010). High-density polyculture and sea cage farming, which are common practices in Southeast Asian marine aquaculture, can also increase interactions between po tential hosts from different species (Zię tara & Lumme 2002, Luo & Yang 2010.…”

“…Host switching may have occurred in Pseudorhabdosynochus coioidesis and P. serrani, which can parasitise closely related grouper species, including Epinephelus coioides, E. bruneus and E. awoara (Luo & Yang 2010). High-density polyculture and sea cage farming, which are common practices in Southeast Asian marine aquaculture, can also increase interactions between po tential hosts from different species (Zię tara & Lumme 2002, Luo & Yang 2010. Yue et al (2009) (Chenoweth et al 1998).…”

“…In Asia, Pseudorhabdosynochus species plague grouper (Epinephelus spp.) culture in the South China Sea (Yang et al 2005, Luo & Yang 2010. Nine diplectanid species, representing 3 genera, have been reported from barramundi, Lates calcarifer (including Diplectanum narimeen, D. penangi, D. setosum, Laticola latesi, L. lingaoensis, L. paralatesi, L. seabassi, Pseudorhabdosynochus epinepheli, and P. lantauensis), some which develop high prevalences and intensities on cultured fish (Leong & Wong, 1990).…”