Mangroves are prime nesting and resting sites for hundreds of shorebirds and migratory bird species, including kingfishers, herons, and egrets. Mangrove roots provide support for filter- feeders like mussels, oysters, and barnacles. The toxic metal levels in four species of fish (Labeobata, Sillaginopsis panigus, Platycepalus fuscus) and shrimp (Penaeus monodon) from Bangladesh have been reported and the associated health risks to consumers reported (Hossainet al. 2022). The findings revealed that only Pb in finfish and Pb, Cu, and Zn in shrimp samples exceeded the national recommended limits, representing possible risks to consumers. P. monodon shrimp had higher levels of metals than fish species. Limited information on heavy metals has been reported for oysters, blue crabs, corals, saltmarsh from the Msimbazi River in Dar es Salaam, Tanzania. A preliminary investigation on the extent of metal pollution (Hg, Cr, Cu, Zn, Fe, Ni, Cd, Mn, Al) was made at Tanzania fisheries Research Institute from samples of sediments and biological indicators. Coral reefs are very important in Tanzania, both ecologically and socio-economically, as major fishing grounds and tourist attractions. These reefs have been partially to severely degraded by human (primarily destructive fishing practices) and natural (particularly coral bleaching) causes. These immediate human causes have been brought about by various socioeconomic root causes, particularly poverty and lack of proper management. The Global Coral Reef Alliance (GCRA) has taken the lead in documenting coral bleaching events worldwide and relating them to climate and weather anomalies as well as locally derived environmental stresses. The goals of this project were to (1) examine metal levels in oysters and saltmarsh, (2) assess the survival of oysters and saltmarsh using the Biorock method mineral accretion and (3) perform an economic analysis of innovative methods to enhance productivity in the cultivation of oysters, seaweed, mussels, and fish. Metals (lead, mercury, arsenic and cadmium) were analyzed in oyster and saltmarsh at the laboratory of Tanzania fisheries Research Institute. Biorock method Accretion Technology increases shellfish settlement while reducing hydroid fouling, keeping oysters and saltmarsh alive and growing under conditions that would otherwise be toxic. This method stimulated a greater settlement of larvae of different marine species. Each hectare of mangrove generates up to US$50,000 a year in mangrove shrimp farming associated with fish and blue crab bringing an estimated US$19 million in income annually to local small holder fish farmers.