Larval Settlement and Epidemiology of Lepeophtheirus salmonis KrOyer, 1837(Copepoda; Caligidae)
نویسندگان
چکیده
This study has been carried out to investigate the biological and environmental parameters influencing the settlement and post-settlement survival of the infective stages of Lepeophtheirus salmonis KrOyer 1837. The abiotic factors investigated were temperature and salinity. Temperature was found to have a significant effect on the settlement success of the copepodids with an inverse relationship between temperature and settlement. Survival of the louse at 10 days post infection showed a decrease at the reduced temperature. Temperature was also shown to have a direct relationship on lice development; higher seawater temperatures resulted in faster development. Regression analysis of temperature and settlement shows a significant correlation. A constant reduced salinity, 24%o, resulted in a reduced ability of the copepodid to infect its host compared with 34%o. Post-settlement survival in 24%o, at approximately 13°C resulted in 5.8% survival of lice to day 10 post-infection compared to 79% in 34%0 salinity. When this experiment was repeated but with elevated seawater temperatures of up to 18°C, survival at the reduced salinity was found to be 75.3%, higher than the ambient control group. The developmental rate at day 10 post-infection of L.salmonis larva at 24%0 was shown to be slower than development at 34%o. Distribution of the L.salmonis copepodid on its host showed the highest settlement on the gills and on the fins, particularly the pectoral and dorsal fins. Examination of L.salmonis survival at day 10 post-infection indicated the highest losses on the gills and the pelvic, caudal and dorsal fins. Settlement on the pectoral fins showed the highest settlement and the greatest survival.
منابع مشابه
Identification and characterisation of the ecdysone biosynthetic genes neverland, disembodied and shade in the salmon louse Lepeophtheirus salmonis (Copepoda, Caligidae)
The salmon louse is a marine ectoparasitic copepod on salmonid fishes. Its lifecycle consists of eight developmental stages, each separated by a molt. In crustaceans and insects, molting and reproduction is controlled by circulating steroid hormones such as 20-hydroxyecdysone. Steroid hormones are synthesized from cholesterol through catalytic reactions involving a 7,8-dehydrogenase Neverland a...
متن کاملThe Salmon Louse Lepeophtheirus salmonis (Copepoda: Caligidae) Life Cycle Has Only Two Chalimus Stages
Each year the salmon louse (Lepeophtheirussalmonis Krøyer, 1838) causes multi-million dollar commercial losses to the salmon farming industry world-wide, and strict lice control regimes have been put in place to reduce the release of salmon louse larvae from aquaculture facilities into the environment. For half a century, the Lepeophtheirus life cycle has been regarded as the only copepod life ...
متن کاملDisruption of host-seeking behaviour by the salmon louse, Lepeophtheirus salmonis, using botanically derived repellents.
The potential for developing botanically derived natural products as novel feed-through repellents for disrupting settlement of the salmon louse, Lepeophtheirus salmonis (Caligidae) upon farmed Atlantic salmon, Salmo salar, was investigated using an established laboratory vertical Y-tube behavioural bioassay for assessing copepodid behaviour. Responses to artificial sea water conditioned with t...
متن کاملFirst record of sea lice Lepeophtheirus curtus (Copepoda, Caligidae) in sea-farmed Epinephelus marginatus (Serranidae) in Brazil.
متن کامل
How sea lice from salmon farms may cause wild salmonid declines in Europe and North America and be a threat to fishes elsewhere.
Fishes farmed in sea pens may become infested by parasites from wild fishes and in turn become point sources for parasites. Sea lice, copepods of the family Caligidae, are the best-studied example of this risk. Sea lice are the most significant parasitic pathogen in salmon farming in Europe and the Americas, are estimated to cost the world industry euro300 million a year and may also be pathoge...
متن کامل