Beside the traditional method to look into the catch/unit effort there is another way of survey and it is called as Underwater Visual Census (UVC) that has been the predominant survey tool (e.g. diving) in researches on shallower coral reefs and temperate rocky reefs. Here are some literature:
Hi, Dola.....Thank you so much for your prompt reply. UVC, indeed is becoming a popular tool in the present day scenario. But, I think, India is still lacking this aspect and it is really very expensive to conduct such kind of sampling for a longer period of time. So, is there some other alternative???????
i think censusing can helps you in this matter. you should establish something like grab in benthic surveys. then you can count each species in each sampling unit. then generalize the count to the all study area. like Swept area method.