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Abstract: Understanding the trade-off relationships between ecological, economic and social objectives is important in designing policies to manage or restore ecosystems. Using the northern South China Sea (NSCS) as a case study, we explore the trade-offs between conservation and socio-economic objectives in managing fisheries in tropical marine ecosystems. Using a numerical optimization routine and ecosystem modelling (Ecopath with Ecosim), the study shows that current management of the NSCS is sub-optimal both in terms of conservation and economic objectives. Therefore, improvement in both conservation status and economic benefits can be achieved by reducing fishing capacity. However, the implementation of conservation plans may be hindered by the reduced number of fisheries-related jobs and the lack of alternative livelihoods. Similar trade-offs are apparent in many tropical marine ecosystems. Thus, this paper supports claims from previous studies that solving the alternative livelihood problems appears to be a priority for improving management and conservation in these ecosystems. A buy-back scheme that is funded by fishers might be effective in reducing fishing capacity. However, public funds are required if management objectives focus strongly on conservation. This might be justified by the direct or indirect benefits to society that could be provided by well-conserved ecosystems. This study highlights the conflict between maximizing conservation and social objectives, although win–win solutions between conservation and economic objectives may be possible. [Copyright &y& Elsevier]

Abstract: Prager and Shertzer [] made three points on our intergenerational discounting approach presented in Sumaila and Walters [Sumaila, U.R. and Walters, C., 2005. Intergenerational discounting: a new intuitive approach. Ecological Economics 52: 135–142]. We comment on each of these in this short response to their comments. [Copyright &y& Elsevier]

Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world’s small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale. [ABSTRACT FROM AUTHOR]

A third of global fish stocks are overexploited and many are economically underperforming, resulting in potential unrealized net economic benefits of USD 51 to 83 billion annually. However, this aggregate view, while useful for global policy discussion, may obscure the view for those actors who engage at a regional level. Therefore, we develop a method to associate large companies with their fishing operations and evaluate the biological sustainability of these operations. We link current fish biomass levels and landings to the revenue streams of the companies under study to compute potentially unrealized fisheries revenues and profits at the level of individual firms. We illustrate our method using two case studies: anchoveta (Engraulis ringens; Engraulidae) in Peru and menhaden in the USA (Brevoortia patronus and B. tyrannus; Clupeidae). We demonstrate that both these fisheries could potentially increase their revenues compared to the current levels of exploitation. We estimate the net but unrealized fishery benefits for the companies under question. This information could be useful to investors and business owners who might want to be aware of the actual fisheries performance options of the companies they invest in. [ABSTRACT FROM AUTHOR]

The announcement of plans for exploratory oil drilling at a number of offshore sites in Belize raised concerns about the risks associated with drilling, particularly given the socio-economic importance of the marine ecosystem. The current economic value of fisheries and marine ecotourism is estimated, along with the potential revenue from offshore oil and potential economic losses stemming from oil pollution, under various assumptions on risk and uncertainty. Marine fisheries and ecotourism are estimated to generate around US$ 183 million per year. Single-year estimated maximum revenue is higher for oil extraction initially but quickly declines; during a 50 year (two generation) period, total discounted benefits from marine fisheries and ecotourism are estimated at US$ 5.1 billion, compared to US$ 3.2 billion from offshore oil revenue. Following a hypothetical oil spill, discounted losses in marine fisheries and ecotourism due to perception and ecological impacts are estimated at US$ 912 million, with clean-up costs and capital losses of US$ 6.1-10.4 billion. Considering the short extraction life of oil resources compared to fisheries and ecotourism, the difference in benefits increases substantially in favour of the latter with a longer time horizon. A recent public referendum resulted in a 98% vote against oil exploration and a subsequent annulment of oil concessions pending environmental impact assessments. [ABSTRACT FROM AUTHOR]