A Marine Reserve, from functional (where some resource use occurs) to preservation, constitutes a defined space of coastal, marine resources and environment to which specific forms of management is applied which normally includes limited entry, e.g, Bongoyo and Mbudya Island Marine Reserves, whereas, A Marine Park is a specialised version of a marine reserve where various community users and habitation is encouraged through a strict zonation scheme, and emphasis on education, recreation and preservation is highly recommended through participatory management approaches, e.g., Mafia Island Marine Park.

MPA is an area of land and/or sea that is dedicated to the protection and maintenance of biological diversity and natural and associated cultural resources, managed through legal or other effective means (IUCN). The Convention on Biological Diversity (CBD) provides a slightly different definition for a protected area. It states that a protected area is a geographically defined area designated or regulated and managed to achieve specific conservation objectives. However, both the IUCN and CBD definitions state clearly that a site must be set aside principally for conservation if it is to be recognized as a protected area. The term 'MPA' is normally used as a generic term to cover all marine sites that meet the IUCN protected area definition, regardless of purpose, design or management approach. In the case of Tanzania, marine parks (MPs) are relatively large, multiple-use designated areas, while marine reserves (MRs) are smaller areas (uninhabited islands) in which extraction of any marine resources is prohibited.

The primary reasons for creating "Marine Protected Areas" include:

• To preserve biological diversity
• To maintain essential ecological processes and life support system.
• To ensure the sustainable utilisation of species and ecosystems ,and.
• Since the coastal environment supports the social, cultural and economic livelihood of coastal communities through the provision of food, shelter, incomes, employment and basic existence, a MPA helps to ensure and enhance the living standards of the local population. The MPA could also take advantage of the natural endowments and aesthetic attractiveness of the costal and marine environment through promoting recreation,tourism and education oriented activities,thus adding to the local and national economies