The coastal ecosystem of Bay of Bengal (BOB) is described using a mass-balance model of trophic interactions, in order to understand the effects of Set Bagnet (SBN) on the ecosystem. The BOB model encompassed an area of 24,000 km2 and had 14 functional ecological groups of which 13 were living groups and one dead group (detritus). Result showed that all consumers had ecotrophic efficiency (EE) >0.90 indicated that the consumers were heavily exploited in the system. The fishery was operating at a mean trophic level of 2.45. The SBN fishery was characterized with higher fishing mortality rates and large omnivory indices for most of the commercially exploited demersal and pelagic groups. For this fishery, the total primary production requirement for sustainable catch was estimated at 15.11%. However, results of Ecosim simulation elucidated that the key resources like small demersal, small and medium pelagic and penaeid shrimp were likely to show a rapid decline in yields within 5 years due to increasing fishing effort and pressure. In contrast, the palaemonidae and sergested shrimp yields showed an increasing trend as they seem to be able to sustain the high fishing pressure as long as their predators are also harvested. Besides, cephalopod which is a non-targeted group for this fishery also likely to increase in yield with the time being. The two most drastically affected groups in both fishery were likely to be shark and small demersal. Continuous increasing fishing effort of SBN proved to be leading in rapid declines of most of the commercial marine resources and a serious effect on the ecosystem functioning of BOB.
Keywords: Bay of Bengal, Set Bagnet, High fishing pressure, yields, Ecosim.
1. Introduction
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...mass (B) were done until input is equal to output for each box. Both of the gross efficiency and ecotrophic efficiency for all functional groups should be less than one. To achieve mass-balance for all groups, at first adjustments of diets were a performed since feeding habits of some organisms are highly labile and mainly depend on food sources that are available in the ecosystem. The second step involved the manual adjustments in biomass for different groups that were estimated by applying weighted average method from the survey data of multiple years. In Ecopath, the trophic levels are the output or calculated results. If they are not in accordance with expectation, one can check the diet compositions of the input data. If uncertain about the trophic levels of fish, for example, one can check with FishBase for the trophic levels of same or similar species.
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With more primitive ocean species occurring more in our oceans many problems are posed by them. One thing is that they interfere more and more with the cycle that our oceans go through the animal’s way of life is changing. For example the Australian algae has definitely disrupted ecosyst...
“The wealth of the nation is its air, water, soil, forests, minerals, rivers, lakes, oceans, scenic beauty, wildlife habitats, and biodiversity . . . that’s all there is” (Gaylord). Throughout the recent decades, the wealth of the Chesapeake Bay and adjacent rivers have been affected by a phenomenon called eutrophication. that occurs when there is an excess of a nutrient limited in the water, such as nitrogen, phosphorus, and sediments (Eney 2009). Those nutrients are naturally good in the environment since they help the bottom of the food chain, but a lot is not always good, and the Chesapeake Bay has been receiving too much of these nutrients during the last years. This causes an explosion of growth an algae (algae bloom). Since algae are photosynthetic their life after the eutrophication occurs is very short. Many algae die without being eaten by the primary consumers and the one that remains without eating after dying begins to decompose, leaving at the bottom of the water an anoxic zone "dead zone" where there is no oxygen for the organisms that live there to survive.
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and the effect it will have on the coast before they are allowed to be
Arunatilake, M., Gunawandena, A., Marawila, D., Samaratunga, P., Semaratne, A., & Thibbotuwawa, M. Analysis of the Fisheries Sector in Sri Lanka. Institute of Policy Studies of Sri Lanka (IPS). Retrieved February 10, 2014, from http://www.ips.lk/
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