Biological control of Alitropus typus (Isopodes: Flabellifera) in Pakistan

The worth of Pakistan fish and sea food industry is about to $1.2 billion annually. But fish

farming is plagued with disease issues due to high parasitic infestation and commercialization.

Various developmental stages in parasites and many interdependent influences of macro and

micro-enviroment effect the paratsitic fauna of fish.  The present study reveals the external

morphology and control the highly infested ectoparasite Alitropus typus (Isopodes: flabellifera)

which have contributed disease problems to the fish industry of Pakistan. In external

morphometric parameters i.e. full body length, length of annental segments, length and width of

abdominal segments, length and width of head, length of right and left mandible, length of right

and left maxillae, length and width of  pereopods (Basis, Ischium, Merus, Carpus, Propodus and

Dactylus) , length and width of Pleotelson and Uropods were measured and statistically analyzed

for mean, standard deviation, standard error, coefficient of variability, confidence interval (95%)

and analysis of variance. To determine anti-isopods potential of ethanol extracts of leaves of

Euphorbia helioscopia, Ajuga bracteosa, Cannabis sativa and Callistemon citrinus, 15

specimens were placed in each container treated with different concentrations (1000 ppm, 5000

ppm, 10000 ppm). The percent mortality A. typus was observed after 12 hrs, 24 hrs and 36 hrs .

The results were analyzed by using one way Anova and Tukey test. Among all extracts

bioassays, the maximum activity was observed in extracts of Euphorbia helioscopia, Ajuga

bracteosa, Cannabis sativa whereas Callistemon citrinus do not show any mortality. To estimate

the toxicity level of each plant extract was calculated by determining LC50 and LC90.  The Protein

(mg/g), Carbohydrate (mg/g) and Lipid (mg/dl) (triglyceride and cholesterol) content variations

in effected isopods were estimated by Lowry’s method, phenol sulphuric acid method. Protein

contents of isopod species were decreased markedly as compared to the experimental control

group.In prey predator relationship crabs as  predators were used to control the infestation

behaviour of A. typus in which each crab consumes 7  isopods/week and also acts as a scavenger

for dead organisms.