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This study aimed to develop a sustainable method for synthesizing quantum dots (QDs) from crab-derived chitosan waste and evaluate their potential applications in marine environmental monitoring and aquaculture. We employed a microwave-assisted green synthesis protocol where chitosan extracted from local crab processing waste was dissolved in 1% acetic acid, subjected to microwave digestion (180 °C, 20 min), neutralized to pH 7, and purified through centrifugation, filtration, dialysis, and lyophilization at − 68 °C. Comprehensive characterization using multiple analytical techniques (AFM, FTIR, XRD, UV–Vis, photoluminescence) revealed QDs with uniform size distribution (2–4 nm), crystalline structure (62% crystallinity index), high quantum yield (46 ± 3%), and exceptional stability in marine environments (87% fluorescence retention in 3.5% NaCl). The QDs demonstrated excellent shelf-life (> 90% activity after 6 months at 4 °C) and photostability (8% reduction after 6 h of continuous UV exposure). Performance testing confirmed their effectiveness for water quality monitoring (detection limits 0.5 μM for Hg²⁺, 0.8 μM for Pb²⁺), antifouling applications (78% biofilm reduction), and pollutant remediation (adsorption capacities 187 mg/g for methylene blue, 142 mg/g for Cu²⁺). We conclude that crab-derived chitosan QDs represent a viable circular economy approach to transform seafood industry waste into high-value nanomaterials with significant applications in sustainable aquaculture and marine environmental protection, supporting blue economy innovation through waste valorization while reducing environmental impact.

Blue crab aquaculture faces challenges in optimizing feed formulations that balance nutritional requirements with sustainability. This study evaluated three innovative feed formulations incorporating unique ingredient combinations: a specialized high-protein formulation using novel protein hydrolysates (D1), a marine-based diet enriched with bioactive compounds from sustainable sources (D2), and an advanced plant-based formulation with enhanced digestibility through fermentation (D3). Growth performance, survival, energy conversion efficiency, molting frequency, and meat quality were assessed over 16 weeks. The marine-based diet (D2) achieved superior results with 92% weight gain and 95% survival rate, significantly outperforming the commercial control. This research demonstrates the potential of novel ingredient combinations and processing techniques in enhancing blue crab aquaculture productivity while addressing sustainability concerns.

The blue crab (Callinectes sapidus, Rathbun 1896) has become a significant source of raw materials in biotechnology and nanotechnology due to the biomaterials present in its shell. Natural polymers such as chitin and chitosan, derived from the crab's shell, are particularly noteworthy for their environmentally friendly and biologically compatible properties. These biopolymers provide an innovative alternative in the synthesis of quantum dots (QDs). Quantum dots are favored in various applications, including biomedical imaging, environmental sensors, and energy storage, due to their superior optoelectronic properties. Chitosan obtained from blue crab shells acts as both a stabilizer and a coating agent in the green synthesis of quantum dots. This process minimizes the use of toxic chemicals, thus promoting environmental sustainability. Moreover, the antimicrobial and biodegradable properties of chitosan enhance its usability in biomedical applications. For instance, biocompatible carbon-based quantum dots have shown promising results in cancer diagnostics and drug delivery systems. The synthesis of quantum dots using biomaterials is more cost-effective and environmentally friendly compared to traditional methods. Furthermore, utilizing blue crab shells as a waste material contributes to both marine ecosystem preservation and the circular economy. These synthesis methods are reported to create a significant paradigm shift in the field of sustainable technology development. In conclusion, the synthesis of quantum dots using biomaterials derived from blue crabs has the potential to reduce environmental impacts while serving advanced technological applications. This approach significantly contributes to the development of biotechnological innovations and sustainable development goals.

For biofuels and nutraceuticals, the green microalga Haematococcus pluvialis (Chlorophyceae) is a prospective source of biomass and lipids. This study examined how biomass production and lipid accumulation were affected by temperature (10 °C, 20 °C, and 30 °C) and potassium nitrate (KNO₃) concentrations (0.41 g/L, 0.31 g/L, 0.21 g/L, 0.10 g/L, and 0). The findings showed that the largest biomass (0.665 ± 0.200 g/L) was produced at a potassium nitrate concentration of 0.21 g/L at 20 °C, whereas the highest lipid content (46.31 ± 0.026% dry weight) was produced at a temperature without nitrate. Notably, a balanced result was obtained with a modest nitrate content (0.10 g/L) at 20 °C, yielding significant biomass (0.560 ± 0.136 g/L) and lipids (40.30 ± 0.012% dry weight). These results highlight how crucial it is to optimize cultivation settings in order to increase H. pluvialis's dual productivity, offering important new information for its industrial-scale use. By adjusting growing conditions, this research helps meet the need for renewable resources worldwide by promoting the production of high-value bioproducts and sustainable, commercially viable algae-based biofuels.

Data from twelve distinct crab species collected in the USA between 1953 and 2021 were used in this investigation. By using the panel data analysis approach, estimates were generated on the data between 2007 and 2021 in light of the information gathered after gathering the nutritional values of the linked species. Based on the species of crabs that are cultivated or harvested, the purpose of these calculations is to ascertain the nutritional values of the crabs that will be available in the upcoming years. Knowing this is crucial because of the growing population and depletion of food supplies. The study's findings were compared with the actual values, and it was highlighted that it would be appropriate to estimate values that are closest to the actual values and investigate whether these estimates will be sufficient to fulfill the world's growing food supply.

In aquaculture hatcheries, microalgae, including Nannochloropsis sp. (D.J. Hibberd, 1981), are utilized as live food sources, The development of algal cultures employed in inoculation can satisfy the need for Nannochloropsis. This process begins with stock cultures on a laboratory scale and advances to intensive algal cultures in higher volume structures set up in both indoor and outdoor environments. The aim of the study was (1) to determine the specific growth rate (μ) of Nannochloropsis sp. grown under labora-tory conditions as a live feed source to feed crab larvae of Callinectes sapidus (Rathbun, 1896) (Brachyura: Portunidae), and (2) to determine the fatty acid and ami-no acid compositions of Nannochloropsis sp. According to the study's findings, Nan-nochloropsis sp. had a specific growth rate (μ) of 0.553 ± 0.004 when grown in Guil-lard F/2 culture medium with aeration, 25 ppt salinity, and 25 0C room temperature. Out of all the necessary fatty acids, DHA, at 22:6 (ω-3) made up 0.5 ± 0.07 percent, and EPA, at 20:5 (ω-3) made up 24.25 ± 3.45 percent. The total amino acid content of Nannochloropsis was observed to range from 0.00 ± 0.00% (taurine) to 16.35 ± 3.56% (proline).

The purpose of this study was to determine the blue crab's growth parameters and explore potential adaptations while it was kept in an earthen pond for ninety days. After samples from October 2012 and August 2013 were analyzed, the breeding and biological characteristics of the blue crab (Callinectes sapidus Rathbun, 1896) in the South Aegean were determined. Blue crabs' adaptation to the earth pond, growth circumstances, and morphometric measuremalets using information from the literature are discussed. The process of adaptation took a week, during which time individual blue crabs were seen to begin feeding. The Ege the University Faculty received nine units from the Pond in the Kusadasi/Güzelçamlı area that were examined in cages with 108 distinct experimaletal groups of persons out of 20 living humales.

Reductions in the size of mature blue crabs, Callinectes sapidus, which are commercially harvested, are of concern to the aquaculture industry. Through their role in the production of viable offspring, aquaculturists focus their attention in particular on female crabs, although the phenomenon will, of course, also affect the males. Meanwhile, decreases in size at maturity throughout the crab population may be the result of temperature alterations, at present also due to global climate change. Temperature-based shifts in growth can lead to changes in reproductive efficiency, as well as in size and age at maturity. In this study, the effects of temperature on the moulting frequency of blue crabs were investigated and survival rates have been calculated. The purpose of this study was to investigate the temperature dependence of survival and of the moulting processes for blue crab larvae, and to determine the effect of increasing temperature on moulting. The stages from zoea-1 to zoea-5 were examined at 16, 22, 26 and 30°C. The results show that there is a significant difference in growth and moulting, depending on the rearing temperature. As the temperature increases, the interval between moulting days can be seen to be shortened, and increasingly so with the progress in the growth of the crabs. Moulting-interval days became less with the growth of the crabs. The effect of a rise in temperature on growth per moult is also significant, and along the temperature range tested the optimum temperature was found to be 26°C. A reduction in the length of the intermoult period was observed from the lowest to the optimum temperature, while a sudden, sharp increase in the intermoult period above 26°C was observed as well.

This study investigated the well-being and survival of larvae of the blue crab, Callinectes sapidus, under the influence of several abiotic and biotic factors, in order to collect relevant data for optimizing the larval period in the culture of this species. Aspects tested and examined were primarily: water volume, stocking density, salinity, (frequency of) moulting, starvation, mortality, cannibalism, behavioural aspects (e.g., mobility, intraspecific aggression), larval development, as well as the influence of ground colours. All aspects appeared to influence the duration and success of the larval period, from zoea-I to megalopa, but the main difference was observed to be related to the (water) volume of the culture tanks.