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Three parasitic copepods (Siphonostomatoida) belonging to three different genera were recovered from marine fishes of Iraq, and are listed here as new records. The sea lice Caligus epinepheli Yamaguti, 1936 (Caligidae) was collected from the Japanese threadfin bream, Nemipterus japonicus (Bloch). It had been frequently reported from teleost fishes around the world. The second record, comprising male and female, was another caligid, rarely caught from fishes — Hermilius longicornis Bassett-Smith, 1898, collected from the giant catfish, Netuma thalassina (Rüppell). This paper features the first description of the male of the latter species. The third record was the lernanthropid, Lernanthropinus temminckii (von Nordmann, 1864) (Lernanthropidae), redescribed based on the specimens collected from the greater lizard fish, Saurida tumbil (Bloch) (Synodontidae). In order to clarify its taxonomic status, our specimen was compared with the holotype of L. gibbosus (Pillai, 1964) from the collections of Zoological Survey of India, Kolkata, and the syntypes of L. sauridae Do in Ho and Do, 1985 and L. temminckii from the collections of the Smithsonian Institution, Washington D.C. We found similarities in the morphology of the body, mouthparts, and legs 1–4 in three above-mentioned species. The prominent feature, the setation pattern of legs 1 and 2 was similar in all the female specimens examined. In the light of this, we formally relegate L. gibbosus and L. sauridae to synonymy with L. temminckii. Another important similarity is that Lernanthropinus gibbosus, L. sauridae, and L. temminckii have exclusively been parasitic on lizardfishes (Synodontidae). The attachment site of all three copepods reported form Iraq were the gill filaments.
Background. Arctic charr, Salvelinus alpinus (L.), are known to harbour significantly more sea lice, Caligus elongatus von Nordmann, 1832, than do Atlantic salmon, Salmo salar L. This research investigated whether this is due to differences in initial infection or to resettlement/loss of mobile adults. Skin mucus protein profiles and epidermal histology were also studied as two characteristics that might help explain interspecific differences in host susceptibility. Materials and Methods. Atlantic salmon and Arctic charr were sampled from the sea-pen after 12 weeks of exposure to natural infection. Fishes were examined for sea lice counts and mucus was analysed for protein profiles using standard methods of poly-acrylamide gel electrophoresis. Epidermal tissue of fishes around chalimus attachment sites was also examined by transmission electron microscopy. Results. Interspecific differences in host susceptibility were determined not to be due to differences in initial infection rate, as charr and salmon had similar numbers of attached chalimi. Adult parasites were significantly more numerous on charr as a result of resettlement of adults lost by other fishes in the area. Gel electrophoresis indicated that salmon had a greater abundance of skin mucus proteins than charr, particularly in the 30–42 and 67–94 kDa range. Ultrastructural analysis of epidermal tissue indicated that charr had more mucous cells and showed evidence of possible osmotic stress. Interspecific differences also existed in intercellular adhesion characteristics. Salmon and charr showed a similar absence of inflammation around chalimus attachment sites. Conclusion. Artic charr had a more intense infection with Caligus elongatus than did salmon corresponding to fewer potentially antagonistic proteins in the mucus. Perhaps also, the epidermis of charr provides more easily accessible food for the sea lice. Higher levels of stress in charr in sea water may also have predisposed them to higher sea lice infections.
This paper presents the first records of the parasitic copepod Caligus furcisetifer Redkar, Rangnekar et Murti, 1949 beyond Indian waters, specifically, on the body surface and head of the critically endangered largetooth sawfish (commonly referred to as the freshwater sawfish in Australia), Pristis microdon Latham, 1794 (Elasmobranchii, Pristidae), in brackish tidal waters of the Fitzroy River in the Kimberley region of Western Australia and the Leichhardt River in the Gulf of Carpentaria in northern Queensland. This represents a geographic range extension of ∼8000 km for this parasite. Further, it is only the second member of the genus Caligus to be found on an elasmobranch host in Western Australia and it is the first time this species has been reported from the Southern Hemisphere. Male biased dispersal of P. microdon may be the vector in which the parasite has dispersed from India across to northern Australia, or vice versa. A decline in populations of the critically endangered P. microdon (and possibly other pristid species) in these regions may lead to a concomitant decline in their parasite fauna.
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