Clupeoid fish can be considered excellent candidates to understand the role of mitochondrial DNA in adaptive evolution, as they have colonized different habitats (marine, brackish, freshwater, tropical and temperate regions) over millions of years. Here, we investigate patterns of tRNA location, codon usage bias, and lineage-specific diversifying selection signals to provide novel insights into how evolutionary improvements of mitochondrial metabolic efficiency have allowed clupeids to adapt to different habitats. Based on whole mitogenome data of 70 Clupeoids with a global distribution we find that purifying selection was the dominant force acting and that the mutational deamination pressure in mtDNA was stronger than the codon/amino acid constraints. The codon usage pattern appears evolved to achieve high translational efficiency (codon/amino acid-related constraints), as indicated by the complementarity of most codons to the GT-saturated tRNA anticodon sites (retained by deamination-induced pressure) and usage of the codons of the tRNA genes situated near to the control region (fixed by deamination pressure) where transcription efficiency was high. The observed shift in codon preference patterns between marine and euryhaline/freshwater Clupeoids indicates possible selection for improved translational efficiency in mitochondrial genes while adapting to low-salinity habitats. This mitogenomic plasticity and enhanced efficiency of the metabolic machinery may have contributed to the evolutionary success and abundance of Clupeoid fish.
Biofouling is a major issue in aquaculture cages and nano materials based antifouling strategies became more prominent in recent years. Polyethylene aquaculture cage net surface which is modified with polyaniline and nano-copper oxide (CuO), reported to have biofouling resistance. Leaching of nano CuO from the net to the aquatic environment and its bioaccumulation in fish is the major concern against the technology adoption. The present study aimed to understand the accumulation of copper in fishes grown in a nano CuO treated aquaculture cage net. Studied the leaching pattern of nano CuO, biofouling inhibition and changes in strength of the cage net due to the nano CuO treatments. Fishes grown in the treated cages exhibited normal growth characteristics with no signs of abnormalities and also copper in their organs were within the prescribed standard limit. The CuO treated cage net exhibited excellent biofouling resistance and the percentage of occlusion of mesh by foulers were 56.77% more efficient than untreated cage net. Rate of nano CuO leached to the aquatic system was less than 8 ?g/g?d. The fouling organism assemblage on untreated and treated net was 18 and 11 species, respectively. Major calcareous shelled foulers were absent on treated nets. The study highlighted the potential application of nano CuO treatment to control biofouling in aquaculture cages.
An experimental culture of snubnose pompano, Trachinotus blochii was conducted for 210 days in low saline water to understand the growth potential in small indigenous Re-circulatory Aquaculture Systems (iRAS) using low cost fishmealbased diet developed for pompano. In the present study, snubnose pompano has reached the marketable size (287.32±4.84 g) during the culture period with excellent feed conversion ratio of 1.74±0.01 and average daily growth of 1.32±0.02 g/day. Harvested fish showed viscerosomatic index, hepatosomatic index and intra-peritoneal fat ratio of 4.98±0.21, 0.99±0.09 and 1.45±0.16 %, respectively which enhanced the head-on muscle yield (80.57±3.25 %) and fillet yield (52.22±2.27 %). The survival percentage of T. blochii reared in the iRAS was 88.89±3.51 %. The cost of the diet developed for snubnose pompano is well below the commercially available marine fish feeds. The present study suggested that snubnose pompano can be successfully cultured in low saline sea water iRAS using low cost fishmeal-based diet.
Bioactive compounds from marine macroalgae are gaining immense attention for their application as natural ingredients in various nutraceuticals and food supplements. The present study evaluated the medicinal properties of the organic extracts of four each of brown and red marine macroalgal species, using various in vitro assays. Organic extracts of brown algae of Fucophycidan subclass, such as Sargassum plagiophyllum, Turbinaria decurrens, and red alga Hydropuntia edulis, displayed potential inhibitory properties against antioxidants (IC50 0.2–0.8 mg/mL) and carbolytic enzymes (IC50 0.2–0.9 mg/mL) compared to those exhibited by other studied algae. Noticeably, organic extracts of red alga H. edulis and brown alga T. decurrens could effectively attenuate pro-inflammatory 5-lipoxygenase (IC50 0.4–0.6 mg/mL), thereby demonstrating their potential application to dissuade inflammatory pathogenesis. This study demonstrated the predominantly available brown and red macroalgae as potential marine bioresources to develop functional food candidates.
In many coastal communities in Southeast Asia and the Western Indian Ocean, aquaculture is an alternative income-generating activity, aimed at improving local economies and enhancing food security. While aquaculture and fisheries management tend to focus on production, which is male-centric, women are important actors in certain types of small scale aquaculture production (shrimps, mussel, seaweed, crab fattening) and they are major participants along aquaculture value-chains. Women’s specific rights and needs are missing in almost all global normative aquaculture or fisheries policies, thus weakening their opportunities and failing to protect their rights. Guidelines for implementing gender equality in the fisheries sector are lacking, actions are unfunded, and officials do not know what to do. Women’s work is often part of a global value chain in which the women hold little power. Furthermore, fisheries policy boundaries themselves are very narrow and specific, having little sway over many of the activities that women perform. To overcome this, the Gender in Aquaculture and Fisheries Section (GAFS) has argued for gender analyses covering the whole value chain, since this makes visible activities that are at the fringe of fisheries/aquaculture policies and should help expand the policy coverage.