Md. Rashed-Un- Nabi’s research while affiliated with University of Chittagong and other places

Macroscopic algae known as seaweeds comprise a virtual element of maritime ecosystems. It refers to thousands of species of marine algae that are multicellular and macroscopic. Seaweeds frequently accumulate in shallow water or create dense growths on rocky shorelines. Many exhibit a well-established zonation around the seashores, where the water is at least 50 meters deep. Certain seaweed species, like kelps, safeguard food sources by acting as key nursery habitats for fisheries and other marine animals. Other seaweed species, such as planktonic algae, are crucial in absorbing carbon dioxide and generating at least half of the oxygen on Earth. Seaweeds are becoming more and more popular because of their inherent qualities. Numerous advantageous nutritional bioactive substances, including fibers, polysaccharides, pigments, minerals, ascorbic and β carotene vitamins, were found in them. Together with being between 80 and 90 percent water, they also have minimal fat and calorific value and high quantities of vital amino acids and fatty acids. These bioactive substances have demonstrated antiviral, anticancer, antibacterial, and antioxidant properties in numerous investigations. Seaweeds are recognized as a highly valued marine product that has huge industrial applications worldwide. The Food and Agriculture Organization of the United Nations stated that the total worldwide algae output was 36 million tons wet weight in 2020 in its most recent State of World Fisheries and Aquaculture (SOFIA) report (FAO, 2022). This comprises wild and farmed seaweed and microalgae, however, the latter amounts are less significant because they total less than 100,000 tons wet weight. The worldwide algae business is currently valued USD 16.5 billion (Bn), and approximately mostly consists of food goods for human use (FAO, 2022). According to a World Bank assessment from 2023, the development potential of eleven growing seaweed markets might reach US$11.8 Bn by 2030. The worldwide market for seaweed farming is anticipated to grow from US$ 20.57 Bn in 2022 to US$ 43.66 Bn by 2032 with a CAGR of 7.8% A significant portion of the world's seaweed is grown in East and South Asia. 5%-10% of the world's aquaculture output comes from the cultivation of seaweed. In addition, according to Persistence Market Research's (2022) analysis of the worldwide aquaculture industry, red seaweed and brow seaweed are the second and third-largest species, respectively. Seaweeds are widely utilized as food, as components of fertilizers and cosmetics, and in the manufacturing of hydrocolloids (such as agar and alginate). As one of the main producers in the marine food chain and a contributor to the oxygen supply in the water, seaweeds are significant to the ecology. Certain seaweeds possess the ability to extract heavy metals from water, making them suitable for use in biomonitoring and bioremediation of such contaminants. To survive the various environmental pressures to which they are subject, seaweeds also have great survival tactics. Together with their distinct physiology and life cycle, seaweeds provide fascinating study subjects for all the above reasons. A dictionary is a reference book listing alphabetically terms or names important to a particular subject or activity along with a discussion of their meanings and applications. The word "seaweed dictionary" refers to a glossary that uses definitions or different explanations of terminology to help understanding the terms used in seaweed research easier. This dictionary includes terminology that is likely to be associated with seaweed or its associated ecosystems. We gathered the data by following several links. We are making a concerted effort to make seaweed research more accessible to scientists. It will assist you in comprehending the many terms used by algae or seaweed specialists.

Feed mill sweepings (FMS) were used as the substitute of the commercially formulated feed (FF) for rearing GIFT Tilapia. The average moisture, crude protein, fiber and carbohydrate, fat and ash content of the FMS were 13.23%, 34.92%, 26.07%, 5.96% and 19.80% respectively. For FF these values were 14.83%, 28.49%, 31.57%, 8.71% and 16.41% respectively. No significant differences was observed in the proximate biochemical composition between FMS and FF. Average total weight gain in 60 days was observed to be 47.22 g and 53.45 g for FMS and FF respectively with no significant difference. The mean instantaneous growth rate per day was found 4.15±0.96% for FMS and 4.32±1.03% for FF respectively. The survival rate was 83% for FMS and 84% for FF respectively. A comparatively lower FCR that achieved with FMS (1.91) over the FF (1.97) suggested that feed mill sweepings can be used as a substitute to formulated feed in GIFT tilapia culture.

Sanctuaries are widely regarded as a protected area where fishing has been placed under some restrictions by local, state, regional and national authorities for the conservation and management of fisheries resources. These sanctuaries have a broad array of positive and negative social, economic, cultural and political impacts on fishers. This study aims to analyze the socio-economic and ecological benefits and costs of hilsa sanctuaries to protect single most important hilsa species using Sustainable Livelihood Approach (SLA). Under the Protection and Conservation of Fish Act of 1950, six sites along the Padma, Meghna, Tetulia, and Andharmanik rivers have been designated as hilsa sanctuaries. Findings of the current study revealed that most fishers perceived production of hilsa and other species were increased as a direct consequences of sanctuaries establishment. However, a considerable proportion of hilsa fishermen was found to have low socioeconomic capital, as measured by monthly income, housing circumstances and asset ownership. During the restricted fishing season in the sanctuaries, these households are particularly vulnerable to food insecurity. The government’s compensation scheme is a good example of payment of ecosystem services in an open water fishery; however, this scheme does not include all the affected fishers. It is found that hilsa sanctuaries lead to income loss of the poor fishers which is insufficiently compensated by government support program. To compensate income loss, fishers resort illegal fishing which undermine the success of sanctuary. If the sanctuaries are to function effectively, affecting fishers must be addressed by offering enough compensation schemes so that fishers are able to support their families. Moreover, some fishers believed that a co-management approach involving fishers and government is the possible best management option for operating sanctuaries in a sustainable way.

The ubiquitous presence of microplastics (MPs) across all oceans has emerged as a signi cant marine hazard as worldwide plastic production continues to grow. Now and during the next 20-30 years will be the time to confront the implications of the plastic industry's rise, which has resulted in the large-scale global production of millions of plastic-based items, varying from a single pen to automobiles. Inappropriate management, lack of awareness of the detrimental effects, reckless universal use, and the indiscriminate disposal of plastic based synthetic materials, has turned Earth into a "plastic planet". It is critical to have a throughout understanding of MPs' potential from sink to source as well as the processes that govern their distribution and uptake and exchange in ecosystems, to properly comprehend their potential consequences and ecological harm. The goal of the present study was to identify the scenarios of microplastics structure, functions and subsequent impact to the marine organisms. Diversi ed origins of MPs in the oceans and their negative effects on marine animals have been discussed critically in this review. Because of their small size, these plastic particles are easily ingested by a wide range of marine life (e.g.

The anadromous tropical Hilsa shad formed the largest single-species fishery in Bangladesh, making the highest contribution to the country’s total fish production (14%) and nearly 83% of the global Hilsa catch in 2018. However, increased fishing pressure made the fishery vulnerable, and hence, information on the stock condition and its response to the current degree of removal is essential to explore the future potential for sustainable exploitation. This study carried out a rigorous assessment based on three different methodological approaches (traditional length-frequency based stock assessment method for fishing mortality and exploitation, Froese’s length-based indicators for fishing sustainability, and a surplus production-based Monte Carlo method-CMSY, for fisheries reference points estimation) for the best possible estimates of the Hilsa stock status in the water of Bangladesh. The present findings revealed that the stock is likely to be overfished due to over-exploitation. Depending on the outputs, this study recommended a lower length limit for the catch (>33 cm), distinguished a selectivity pattern (mesh size limit ≥ 8 cm), and proposed a yearly landing limit (within the range of 263,000–315,000 tons) for the sustainable management of the Hilsa fishery in Bangladesh.

The bacterial population plays a crucial role in recycling the organic matter and metabolizing the toxic nitrogenous compounds under biofloc technology (BFT). The biofloc technology has been successfully implemented for several fish species, but not for shrimp culture in Bangladesh. The major objectives of this study were to determine the effects of stocking density on the growth performance of tiger shrimp Penaeus monodon under biofloc technology (BFT) rearing system using commercial probiotics and to investigate the abundance of total heterotrophic bacteria (THB) and vibrio-like bacteria (VLB) in different biofloc treatments and their water quality parameters. The experiment was conducted with three different stocking densities in three BFT tanks (2.5 × 2.0 × 1.0 m) with triplicate and three control tanks filled in clearwater. All these tanks were built with cement and can contain 5000 L of water. Visually healthy, disease-free P. monodon postlarvae (weighted 0.18 ± 0.02 g) were collected from a local hatchery and stocked in three different stocking densities, i.e., 400 PL/m 3 (CW), 400 PL/m 3 (BFT1), 450 PL/m 3 (BFT2) and 500 PL/m 3 (BFT3). Shrimps were fed four times a day with commercial feed (Biomer, 40 % crude protein) for 127 days. Significant differences (P < 0.05) in specific growth rate, food conversion ratio, and protein efficiency ratio of shrimp were found among the treatments and the control group. The overall final biomass in BFT1 (5.88 ± 0.12 kg m 3) was significantly higher (P < 0.05) than that of other BFT groups and the control (3.40 ± 0.09 kg m 3). The present findings showed that the biofloc technology with lower stocking density was reducing the total ammonia nitrogen, nitrite-N, and nitrate-N in water and significantly increased THB and reduced VLB populations.

Information on stock condition and reproductive biology are important for fisheries conservation and management planning. This study examined reproduction, growth, mortality and yield of sulphur goatfish (Upeneus sulphureus Cuvier 1829), which is a low-value food fish abundantly caught as bycatch in artisanal and industrial fishing from the southeast coast of Bangladesh at northern Bay of Bengal. Data were collected monthly obtaining samples from local fish landing center. The gonadosomatic index indicated that U. sulphureus spawns twice a year during January–May and August–October. Fecundity of the fish was positively correlated with the body and gonad weight, and varied from 15 128–97 274 eggs with fish weight 11.30–58.73 g. Monthly length–frequency distribution was analyzed through FISAT software, thus the estimated seasonalized von Bertalanffy growth parameters were L∞ = 21.80 cm, K = 0.54 per year, C = 0.5, WP = 0.1 and Rn = 0.300, respectively. Moreover, the value of seasonalized total mortality coefficient Z (2.24) was smaller than that of the non-seasonalized Z (4.16). The instantaneous natural mortality and fishing mortality, calculated for non-seasonalized total mortality, were 1.31 and 2.86, respectively. Furthermore, the high exploitation rate (E = 0.69) was close to maximum exploitation level (Emax = 0.75) in yield-per-recruit analysis, suggesting that U. sulphureus is being exploited at the MSY (maximum sustainable yield) level. Therefore, further increase in fishing effort may reduce U. sulphureus stocks in the coastal waters of Bangladesh.

The present study was conducted to measure globally alarming of ten heavy metals (Pb, Cd, Cr, Cu, Hg, Al, Ni, Co, Zn and Mn) in surface water and sediment of the Old Brahmaputra River in Bangladesh. The observed order of heavy metal mean concentration in water and sediments is Al > Mn > Ni > Co > Cu > Pb > Zn > Cr > Cd > Hg in mg/l and Al > Mn > Zn > Ni > Pb > Cr > Cu > Co > Cd > Hg in mg/kg, respectively. The significant variations of Cr, Cu, Al and Ni were found in the water of all seasons (p < 0.05), while sediment showed Pb and Hg exhibited substantial changes in terms of seasons (p < 0.05). Principal component analysis and correlation matrix revealed that significant anthropogenic input of Pb, Cd, Cr, Cu, Hg, Al, Ni, Co, Zn and Mn in water and sediment. In case of water, very strong linear relationships exhibited in Ni versus Cu (0.911), Ni versus Al (0.910), Mn versus Co (0.882), Cr versus Al (0.877), Cu versus Cd (0.853), Ni versus Pb (0.850), Zn versus Cr (0.833), Ni versus Cd (0.828), Cu versus Cr (0.827), Al versus Cd (0.827) and Zn versus Co (0.804) at the significance level 0.05. In sediments, very strong linear relationships were noted in Zn versus Cr (0.889), Al versus Pb (0.848), Co versus Al (0.819) and Mn versus Co (0.806) at the significance level 0.05. The result discovered that water and sediment quality of the Old Brahmaputra River became contaminated due to the anthropogenic sources of industrial, domestic and irrigation discharges. This environmental monitoring and assessment research will be useful for the management and planning for the protection of this river.