-Messick,G.(1994). Hematodinium perezi infections in adult and juvenile blue crabs Callinectes sapidus from coastal bays of Maryland and Virginia, USA. Diseases of Aquatic Organisms.19:77-82.
- In Coastal bays of Maryland and Virginia, USA, adults and juvenile blue Crabs (Callinects sapidus) were severely infected with the parasitic dinoflagellate Hematodinium perezi.
The methods:
-monthly samples of live and dead adults, juveniles, and early juveniles were collected using both commercial traps and an otter trawl in coastal bays near ocean city, Maryland, and Franklin city.
- Information on sexes, sizes, number of molting, and the stages were noted.
- The cells of all the crabs were studied and exposed to some chemicals to check under microscopes for the parasite.
- a stable condition (pH, salinity) was used.
Results:
- from August through November, prevalence was higher in small crabs than in large crabs.
- There was no difference between males and females in the prevalence.
- Different morphological forms of the parasite were observed.
- Severely infected crabs had reduced hemocyte numbers.
Discussion:
-this report was the first documentation of hematodinium in early-juvenile blue crabs.
- The end results showed that the prevalence was as high as 100% in one sample of early
juvenile crabs.
- Also, the results suggest that prevalence of the infection is higher in post-molting than in pro-molting crabs.
- Seasonality was due either to environmental factors such as salinity, temperature, or photoperiods, which may control the life cycle of the parasites. Or to the possibility that summer mortality of infected crabs was so high that by fall and winter only uninfected and lightly infected crabs remained to be sampled, thus reducing prevalence.
- In Coastal bays of Maryland and Virginia, USA, adults and juvenile blue Crabs (Callinects sapidus) were severely infected with the parasitic dinoflagellate Hematodinium perezi.
The methods:
-monthly samples of live and dead adults, juveniles, and early juveniles were collected using both commercial traps and an otter trawl in coastal bays near ocean city, Maryland, and Franklin city.
- Information on sexes, sizes, number of molting, and the stages were noted.
- The cells of all the crabs were studied and exposed to some chemicals to check under microscopes for the parasite.
- a stable condition (pH, salinity) was used.
Results:
- from August through November, prevalence was higher in small crabs than in large crabs.
- There was no difference between males and females in the prevalence.
- Different morphological forms of the parasite were observed.
- Severely infected crabs had reduced hemocyte numbers.
Discussion:
-this report was the first documentation of hematodinium in early-juvenile blue crabs.
- The end results showed that the prevalence was as high as 100% in one sample of early
juvenile crabs.
- Also, the results suggest that prevalence of the infection is higher in post-molting than in pro-molting crabs.
- Seasonality was due either to environmental factors such as salinity, temperature, or photoperiods, which may control the life cycle of the parasites. Or to the possibility that summer mortality of infected crabs was so high that by fall and winter only uninfected and lightly infected crabs remained to be sampled, thus reducing prevalence.
No comments:
Post a Comment