Worldwide, the discovery of oil and gas together with other investments in coastal and marine areas have brought high expectations for economic growth and hope for a bright future especially among the local populations in resource-rich countries. However, in countries like Niger, Ghana, and Mexico, resource endowments have been a source of conflict as there have been cases limiting rights to use and access to the resources, access to social services, and inequalities. The situation is not different from what is happening in Tanzania’s southern region of Mtwara where fishing communities’ hope has been turned into fears and conflicts as their access to resources, access to social services have been restricted with the discovery of oil and gas and evolving of other investments. Obstruction of community activities and also settlements relocation to pave way for different projects have further worsened the situation. How and why did such fear arise, and what has been the outcome of it? This study examines this fear and how communities perceive their natural environment in the context of their political environment, socioeconomic pressure, and government policy. The study examines and discusses the effects of investments corporate social responsibility (CSR) on fishing community livelihood services based on analysis of trends from 2005 to 2018 and the Tanzania development indicators in the National Five Year Development Plan (NFYDP) of 2015/16 – 2020/21. The paper is based on intensive fieldwork research where both qualitative and quantitative methods are applied. Statistically, identified CSRs had substantial impacts to livelihood and community social services such as household income, employment rate, access to pipeline water, healthcare centers, primary school classrooms, land tenure and security in the sense that, they coincided with the implemented CSRs except for primary school enrolment and there was no significant mean difference suggesting that there might have been other interventions. Moreover, the majority of those livelihood and social services did not meet the national targets identified in the NFYDP 2016/17 to 2020/21 except for access to primary school classrooms and pipeline water. This implies that investments’ financial returns are at the expense of local people where livelihoods are marginalized and compromised. The situation is amplified by experienced conflicts between investors and communities. It’s therefore recommended to institutionalize the CSRs which are made voluntary to improve performance and meeting locals’ expectations.