This study investigated the availability of marine fish and shellfish species in various fish landing centers in Bangladesh from the Bay of Bengal, focusing on the coastal districts notably Chattogram, Patuakhali, and Borguna regions. Face-to-face interviews were conducted with a total of 330 (110 from each three landing centers) respondents for different aspects of fish biodiversity issues. The secondary data were also obtained from the manager, Upazila Fisheries Officer in proximity of the respective fish landing centers. The results observed that a total of 152 species were found, comprising 144 marine fish and 8 shellfish species, including 30 orders and 69 families dominating Perciformes (56%), Clupeiformes (12%) and Scombriformes (11%), highlighting the rich biodiversity of the marine ecosystem. More than 68% of all marine fish were categorized as Least Concern, with roughly 14% classified as Near Threatened and 6% as Vulnerable. The research examined the factors influencing the presence of these species, including type, availability, commercial status, consumer preferences, economic variables, and income levels. Notably, the highest demand species, hilsa (Tenualosa Ilisha), was found to be closely linked to their availability, while less conventional species like octopus and shrimp exhibited erratic consumer demand despite their value. The study underscored the importance of understanding catching compositions and market dynamics in the fisheries sector, referencing the IUCN red list to address concerns regarding species under threat of extinction. Thus, the findings aim to inform sustainable management practices and enhance the economic viability of the fisheries industry in Bangladesh.