Richness and Diversity of Helminth Communities In the Japanese Grenadier Anchovy, Coilia nasus, During Its Anadromous Migration In the Yangtze River, China

Abstract

To determine the relationship between the species richness, diversity of helminth communities, and migration distance during upward migration from coast to freshwater, helminth communities in the anadromous fish Coilia nasus were investigated along the coast of the East China Sea, the Yangtze Estuary, and 3 localities on the Yangtze River. Six helminth species were found in 224 C. nasus. Changes in salinity usually reduced the survival time of parasites, and thus the number of helminth species and their abundance. Except for the 2 dominant helminths, the acanthocephalan Acanthosentis cheni and the nematode Contracaecum sp., mean abundance of other 4 species of helminths was rather low (,1.0) during the upward migration in the Yangtze River. Mean abundance of the 2 dominant helminths peaked in the Yangtze Estuary and showed no obvious decrease among the 3 localities on the Yangtze River. Mean species richness, Brillouin's index, and Shannon index were also highest in the estuary (1.93 ± 0.88, 0.28 ± 0.25, and 0.37 ± 0.34, respectively) and did not exhibit marked decline at the 3 localities on the Yangtze River. A significant negative correlation was not seen between the similarity and the geographical distance (R 5 20.5104, P 5 0.1317). The strong salinity tolerance of intestinal helminths, relatively brief stay in the Yangtze River, and large amount of feeding on small fish and shrimp when commencing spawning migration perhaps were responsible for the results.The anadromous Japanese grenadier anchovy, Coilia nasus (Temminck & Schlegel, 1846), is distributed in the northwestern Pacific. The fish usually feeds and overwinters in the coastal waters and spawns in freshwater. When the anchovy population distributed in coasts of the East China Sea commences migration, the fish can be first found in the Yangtze Estuary in February and the middle reaches of the Yangtze River in April (Yuan et al., 1980;Yuan, 1987;Li et al., 2007). The anchovy returns to the coasts when spawning is completed from April to October in the same year in the Yangtze River (Yuan et al., 1980;Yuan, 1987;Li et al., 2007).With adaptation of fish to a decline of salinity, parasites in the fish also need to cope with changes in the osmotic pressure. A long stay would reduce survival of the freshwater parasites in salt water or marine parasites in freshwater. The mean intensity of 1 freshwater ectoparasite and 2 endoparasites in Oncorhynchus nerka decreased when reared in seawater for 32-40 wk (Bailey et al., 1989). Survival time of the nematode larva Anguillicoloides crassus in intermediate and paratenic hosts was maximal in freshwater and declined with an increase in salinity (Kirk et al., 2000). Populations of the freshwater monogenean Gyrodactylus salaris in Atlantic salmon Salmo salar declined and became extinct when salinity increased from 7.5% to 33.0% after a few minutes (Soleng and Bakke, 1997). Although some Anisakis spp. larvae with high salinity tolerance survived for more than half a year in freshwater, some survived less than...

Parasites as valuable stock markers for fisheries in Australasia, East Asia and the Pacific Islands

“…Yet Hutson et al (2007) used the polyopisthocotylean Paramicrocotyloides reticularis and the lernaeopodid copepod Parabrachiella seriolae to indicate that Seriola lalandi in southeastern Australia and New Zealand formed a single stock, a finding that closely agreed with genetic and tagging results suggesting that these two parasites at least could have a long residence time. Li et al (2011, 2012) found that the marine polyopisthocotylean, H. lingmueni , survived in large numbers on Coilia nasus which had migrated 500 km in freshwater to spawn, as indeed did the marine acanthocephalan Acanthosentis cheni , whereas the marine hemiurid E. coiliae was lost during the 2-month migration. Where it is not possible to determine experimentally the residence time of the parasites, clues can be obtained from two sources: evidence of dead parasites and a negative correlation between abundance and host age.…”

“…Karlsbakk et al (2003) and Rahimian (2007) found that juvenile herring Clupea harengus lost hemiurids within 7-12 weeks. The hemiurid Elytrophallus coiliae disappeared from migrating Japanese grenadier anchovy, Coilia nasus, over a similar time frame (Li et al 2012). On the other hand, Scott (1969) estimated the residence time of Lecithobothrium botryophorum in the greater argentine, Argentina silus, was between 6 and 12 months.…”

“…Infections of Myxobolus arcticus and Myxobolus neurobius suggested that O. masou in Japanese coastal waters were a complex mix of individuals originating from various rivers in the region (Awakura et al 1995). Li et al (2011Li et al ( , 2012 examined parasite faunas to understand seasonal migrations of the anadromous Japanese grenadier anchovy, Coilia nasus, among the Yangtze River estuary and the East China Sea. Infections of six helminth species (the monogeneans Heteromazocraes lingmueni and Helciferus tenuis, the digenean Elytrophallus coiliae, the acanthocephalan Acanthogyrus (Acanthosentis) cheni and the nematodes A. simplex and Contracaecum sp.)…”

“…Infections of six helminth species (the monogeneans Heteromazocraes lingmueni and Helciferus tenuis, the digenean Elytrophallus coiliae, the acanthocephalan Acanthogyrus (Acanthosentis) cheni and the nematodes A. simplex and Contracaecum sp.) suggested that C. nasus prepare for the spawning migration in spring and early summer and return to the estuary after spawning in late summer (Li et al 2011(Li et al , 2012.…”

“…Northern Australia Summary statistics, one-way ANOVA, Tukey-Kramer pairwise comparisons), multi-dimensional scaling, analysis of similarities (ANOSIM) (Li et al 2012) Seasonal migrations Coilia nasus Yangtze River and East China Sea Summary statistics (mean abundance and prevalence), diversity indices, Kruskall-Wallis tests (Moore et al 2012a) Movement, stock identification Polydactylus macrochir Northern Australia Summary statistics (mean abundance, prevalence), one-way ANOVA, Tukey-Kramer pairwise comparisons, discriminant function analysis, Bray-Curtis similarity classifications (Zischke et al 2013) Stock identification Acanthocybium solandri Pacific and Indian Oceans Summary statistics (mean abundance, prevalence), Chi-squared tests, one-way ANOVA, multi-dimensional scaling, analysis of similarities (ANOSIM), similarity percentages (SIMPER)…”