Macro-invertebrate ectoparasites associated with the mud shrimp, Upogebia major from the west coast of Korea

초록

◎ Background (or Objective) of This Study : Mud shrimps are a very important invertebrate species that deeply burrow in tidal flats and provide a substantial prey base for fishes and water birds. They also act as an ecosystem engineer through the establishment of burrows, and filter volumes of water removing potentially harmful organisms. Recently, we found the dramatic increase in the mud shrimp population and it coincided with the recent collapse of the production of manila clam, Ruditapes philippinarum, in the west coast of Korea that had been stable during the last decade. However, we found also these mud shrimps significantly parasitized by several macro-invertebrates in some places of the Korean clam beds. ◎ Methods : The present study was based on the monthly data collected from three tidal flats in the west coast of Korea, two Seonjae-do areas and one Jugyo site near the Daecheon estuary from October 2011 to October 2012. Sample mud shrimp were collected, measured and weighed, and were inspected for the ectoparasitic macro-invertebrates. ◎ Results & Discussion : We report here three branchial parasitic bopyrid isopods, one montacutid bivalve of thoracic ectoparasite, and one rhizocephalan cirriped of abdominal ectoparasite and they are as follows; (1) Bopyrid isopods: ① Gyge ovalis (Shiino, 1939) ② Procepon liuruiyui An, Williams, and Yu, 2009 ③ Orthione griffenis Markham, 2004 (2) Montacutid bivalve, Peregrinamor ohshimai Shoji, 1938 (3) Rhizocephalan cirriped, Sacculina upogebiae Shiino, 1943 The overall infection rate of the ectoparasitic macro-invertebrates was 15.8% of the 4,148 individuals examined during the study period. And, the results of the study showed that the bopyrid isopods of branchial ectoparasites are the most dominant ectoparasites, of which Gyge ovalis (Shiino, 1939) was the most prevalent with the highest rate of 78% in Jugyo tidal flat in July 2012.