Mediterranean Sea Fry; A Source of Isopod Infestation Problem in Egypt With Reference to the Effect of Salinity and Temperature on the Survival of Livoneca Redmanii (Isopoda: Cymothoidae) Juvenile Stages.

Abstract

Parasitic isopods have received considerable attention as they cause series impacts on their hosts either alone or with other environmental stresses such as water pollution. The present study investigated the infestation status with isopods among the fry collected from the natural sources .Also to demonstrate the effects of different salinity and temperature combination on the survival rates of the identified isopods under the laboratory conditions. In March 2017,a total of 16 thousand mugiliid fry were sampled from The Fry Collection center at Al Behera Governorate ,Egypt and examined for the presence of isopods .Samples were found infested with a rate of 10.6% , the result which practically documented that isopods were introduced into lake Qarun through dumping millions of infected fry from this source without biosecurity procedures. The isolated juvenile isopods were morphologically and molecularly identified as Livoneca redmanii species by using 16S rRNA gene and recorded in the GenBank with accession number: MK584629. The effects of variables of salinity/ temperature combination on the survival% of the identified juveniles showed that the best survival rate(100%) was recorded in salinity 15 -20% at temperature 25⁰C while the lethal combination was in salinity 10, 20,50 and 60% at temperature 35⁰C . Statistical analysis using A-two way ANOVA indicated a significant interaction between the effect of different degree of temperature and variance of salinity% on the survival of L. redmanii juveniles. Analysis of one way ANOVA indicated that the most effective temperature of overall mean temperature affected on survival of juvenile stage was 35 C⁰ while the most effective salinity percentage on survival of Juvenile from overall mean of salinity % was 10% .Results of this study provided applicable procedures which can be recommended as a precaution measures and for eliminating the isopod juvenile stages among the mugiliid fry.

Livoneca redmanii Leach, 1818 (Cymothoidae) a parasitic isopod infesting the gills of the European seabass, Dicentrarchus labrax (Linnaeus, 1758): morphological and molecular characterization study

“…The isolated isopod was identified as L. redmanii based on morphological traits previously described by NL Bruce [ 14 ], RC Brusca and GD Wilson [ 23 ]. Morphological characteristics were similar to those described for comparable parasites isolated from other Egyptian fish hosts, such as A. regius [ 20 ], M. cephalus [ 17 ], S. solea [ 18 ], mugiliid fry [ 22 ], and T. zillii [ 19 ].…”

“…Nerocila orbignyi was discovered infesting 69% of randomly screened D. labrax [ 42 ]. In Egypt, L. redmanii was found in 46.7% of M. cephalus [ 17 ], 20.30% of S. solea in Lake Qarun [ 18 ], 10.6% of mugiliid fry collected from the Mediterranean Sea and transported to Lake Qarun [ 22 ], and an overall infestation rate of 19% among the studied fish species ( T. zillii , Solea sp., and Mugil capito ) with M. capito having the highest infestation rate (36%) [ 47 ]. In addition, prevalence rates of L. redmanii in cultured A. regius in Egyptian northern lakes were 77.1, 77.9, and 78.9% in Al-Madiyyah, Sidi Krier, and El Matareya, respectively [ 20 ].…”

“…Adult parasites are usually seen in male/female pairs in their host’s branchial cavities [ 21 ]. Free-swimming juveniles were surprisingly identified on mugiliid fry collected from the Mediterranean Sea and transported to Lake Qarun [ 22 ].…”

Vector Potential of Cymothoid Isopods in The Transmission of Vibrio alginolytcus in Tilapia zilli and Solea aegyptiaca in Egypt

“…Moreover, V. alginolyticus adhesion on intestinal mucus, a temperature-related virulence factor, occurs at 30 C (Yan et al, 2007). Water temperature also had a significant positive correlation with the isopod infestation rate (Mahmoud et al, 2019). In this study, pH level of 9.0 and 8.7 was recorded in Deeba triangle and Qaroun Lake, respectively.…”

Phylogeny and ultrastructure of Elthusa raynaudii (Isopoda, Cymothoidae) firstly recorded from the invasive silver cheeked toadfish (Lagocephalus sceleratus) (Gmelin 1789) in eastern Mediterranean Sea coast

“…The primers, Fish-F1 (5′AGCC-CTGTTCAATGGGATTA-3′) and Fish-R1 (5′TCCCTGGGGTAGTTTCATCTT-3′), were used with the extracted DNAs to amplify a 532 bp fragment of the 16S ribosomal RNA gene (Thangara et al 2014 ). PCR reaction was done according to Thangara et al ( 2014 ) and Mahmoud et al ( 2019b ).…”