The Effects of Depth and Habitats on Bycatch Distribution in Deployed Fish Traps in Bidong Archipelago, Terengganu – Peninsular Malaysia

Graphical Abstract Highlight Research 1. Fish traps at 20 m depth captured the highest species diversity, while 10 m had the most bycatch abundance. 2. Habitat type strongly influenced bycatch composition and species richness, with differences across the study stations. 3. Artisanal fish traps captured a wide range of species, indicating non-selectivity in fishing. 4. Bycatch composition varied with depth, with demersal species being predominant at greater depths. 5. The study recommends management strategies like time-release mechanisms to minimize the ecological impact of fish traps.   Abstract In many marine ecosystems, the fish population has been correlated to bycatch related activities, the most frequently fisheries activities in Malaysia, while the relative importance of other factors such as the depth of artisanal fish trap remains understudied. We investigate whether the bycatch distribution would be affected by deployment of artisanal fish trap at different depths, placed at extensively studied marine educational university station, the Bidong Island, East Coast of Peninsular Malaysia, Terengganu. The traditional artisanal fish trap with a dimension of 1.52 m x 0.92 m x 0.92 m with the wooden frame and the oval shape funnel with a diameter of 25 cm x 6 cm and 25 cm of entrance depth were used for sample collection. The results show that there are six families, six genera and seven species of fish were successfully captured with a 20 m depth captured more fish species compared to others (i.e., 10 m and 15 m depth). The findings of this study provide evidence of the relationship of fish trap depths and fish distribution in the wild. This information could be useful for fishermen for further deployment of their fish trap within the sampling areas in the future

Effect of dietary supplementation of turmeric, Curcuma longa leaf on growth and health status of African catfish, Clarias gariepinus

High stocking density poses a risk to an aquaculture species' production and health status, increasing their vulnerability to diseases and infection. Feed additive reportedly enhances the growth and health of farmed fish. Therefore, this study evaluated the effects of turmeric, Curcuma longa, leaf powder on the growth performance, digestive enzyme activity, hematology, antioxidative response, and disease resistance of African catfish. A feeding trial was conducted using a control diet and three experimental diets containing powdered C. longa leaf at various levels (0.5%, 1.0%, and 1.5%). After eight weeks, the growth performance of African catfish supplemented with C. longa leaf powder improved significantly (p <0.05), particularly the fish fed with 1.5% turmeric leaf powder. Meanwhile, the FCR was significantly reduced in the treatment groups compared to the control group, where the CL15 group recorded the lowest FCR. Furthermore, the fish fed 1.5% powdered C. longa leaf had substantially higher (p <0.05) lipase, protease, and amylase activities than other groups. Powdered C. longa leaf supplementation also significantly enhanced (p <0.05) the antioxidative responses of African catfish compared to the control group, particularly glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT). In addition, the cumulative survival rate was significantly (p <0.05) higher in fish that received powdered C. longa leaf,with the highest being the CL15 group. In summary, 1.5% powdered C. longa leaf is possibly the optimal dosage for African catfish feed to boost their productivity

Modelling the impact of vector control interventions on Anopheles gambiae population dynamics

<p>Abstract</p> <p>Background</p> <p>Intensive anti-malaria campaigns targeting the <it>Anopheles </it>population have demonstrated substantial reductions in adult mosquito density. Understanding the population dynamics of <it>Anopheles </it>mosquitoes throughout their whole lifecycle is important to assess the likely impact of vector control interventions alone and in combination as well as to aid the design of novel interventions.</p> <p>Methods</p> <p>An ecological model of <it>Anopheles gambiae sensu lato </it>populations incorporating a rainfall-dependent carrying capacity and density-dependent regulation of mosquito larvae in breeding sites is developed. The model is fitted to adult mosquito catch and rainfall data from 8 villages in the Garki District of Nigeria (the 'Garki Project') using Bayesian Markov Chain Monte Carlo methods and prior estimates of parameters derived from the literature. The model is used to compare the impact of vector control interventions directed against adult mosquito stages - long-lasting insecticide treated nets (LLIN), indoor residual spraying (IRS) - and directed against aquatic mosquito stages, alone and in combination on adult mosquito density.</p> <p>Results</p> <p>A model in which density-dependent regulation occurs in the larval stages via a linear association between larval density and larval death rates provided a good fit to seasonal adult mosquito catches. The effective mosquito reproduction number in the presence of density-dependent regulation is dependent on seasonal rainfall patterns and peaks at the start of the rainy season. In addition to killing adult mosquitoes during the extrinsic incubation period, LLINs and IRS also result in less eggs being oviposited in breeding sites leading to further reductions in adult mosquito density. Combining interventions such as the application of larvicidal or pupacidal agents that target the aquatic stages of the mosquito lifecycle with LLINs or IRS can lead to substantial reductions in adult mosquito density.</p> <p>Conclusions</p> <p>Density-dependent regulation of anopheline larvae in breeding sites ensures robust, stable mosquito populations that can persist in the face of intensive vector control interventions. Selecting combinations of interventions that target different stages in the vector's lifecycle will result in maximum reductions in mosquito density.</p

Combinatorial microRNA target predictions

MicroRNAs are small noncoding RNAs that recognize and bind to partially complementary sites in the 3′ untranslated regions of target genes in animals and, by unknown mechanisms, regulate protein production of the target transcript1,2,3. Different combinations of microRNAs are expressed in different cell types and may coordinately regulate cell-specific target genes. Here, we present PicTar, a computational method for identifying common targets of microRNAs. Statistical tests using genome-wide alignments of eight vertebrate genomes, PicTar's ability to specifically recover published microRNA targets, and experimental validation of seven predicted targets suggest that PicTar has an excellent success rate in predicting targets for single microRNAs and for combinations of microRNAs. We find that vertebrate microRNAs target, on average, roughly 200 transcripts each. Furthermore, our results suggest widespread coordinate control executed by microRNAs. In particular, we experimentally validate common regulation of Mtpn by miR-375, miR-124 and let-7b and thus provide evidence for coordinate microRNA control in mammals