Search Results (13)

In order to solve problems with the original crayfish optimization algorithm (COA), such as reduced diversity, local optimization, and insufficient convergence accuracy, a multi-strategy optimization algorithm for crayfish based on differential evolution, named the ICOA, is proposed. First, the elite chaotic difference strategy is used for population initialization to generate a more uniform crayfish population and increase the quality and diversity of the population. Secondly, the differential evolution strategy and the dimensional variation strategy are introduced to improve the quality of the crayfish population before its iteration and to improve the accuracy of the optimal solution and the local search ability for crayfish at the same time. To enhance the updating approach to crayfish exploration, the Levy flight strategy is adopted. This strategy aims to improve the algorithm’s search range and local search capability, prevent premature convergence, and enhance population stability. Finally, the adaptive parameter strategy is introduced to improve the development stage of crayfish, so as to better balance the global search and local mining ability of the algorithm, and to further enhance the optimization ability of the algorithm, and the ability to jump out of the local optimal. In addition, a comparison with the original COA and two sets of optimization algorithms on the CEC2019, CEC2020, and CEC2022 test sets was verified by Wilcoxon rank sum test. The results show that the proposed ICOA has strong competition. At the same time, the performance of ICOA is tested against different high-performance algorithms on 6 engineering optimization examples, 30 high–low-dimension constraint problems and 2 large-scale NP problems. Numerical experiments results show that ICOA has superior performance on a range of engineering problems and exhibits excellent performance in solving complex optimization problems. Full article

Amphibian conservation concerns frequently center on the idea of ‘saving’ them, with the underlying assumption they are the passive victims of anthropogenic environmental change. But this approach ignores the physiological, biochemical, and behavioral flexibility amphibians have employed since they first evolved ~365 million years ago. One overlooked advantage amphibians possess in the struggle for survival, and one humans might use in their efforts to conserve them, is their brains share the same blueprint as human brains, which allows them to acquire knowledge and understanding through experiences—in other words, amphibians have cognitive capabilities that assist them in their effort to survive. Here, we use four examples from our work on the behavioral ecology of Crawfish Frogs (Rana areolata) to form hypotheses about how cognition affects amphibian reaction to environmental and social change. The first two examples describe Crawfish Frog responses to seasonality and reproductive status, the third details their reaction to ecological disturbance, and the fourth describes how their response to the same stimulus changes with growth/age. In each example, we detail the neuronal circuitry thought to be involved and hypothesize the role of cognition. We propose that as one component of our fight to conserve amphibians, researchers should consider the full range of anatomical, physiological, biochemical, and behavioral features amphibians themselves employ in their defense, which are features responsible for their historical evolutionary success up until the Anthropocene. Further, we submit that acknowledging amphibians possess cognitive abilities can enrich interpretations of not only behavioral and ecological observations but also of neuroanatomical and neurophysiological results. Full article

Fuel cell vehicles have been widely used in the commercial vehicle field due to their advantages of high efficiency, non-pollution and long range. In order to further improve the fuel economy of fuel cell commercial vehicles under complex working conditions, this paper proposes an adaptive rule-based energy management strategy for fuel cell commercial vehicles. First, the nine typical working conditions of commercial vehicles are classified into three categories of low speed, medium speed and high speed by principal component analysis and the K-means algorithm. Then, the crawfish optimization algorithm is used to optimize the back propagation neural network recognizer to improve the recognition accuracy and optimize the rule-based energy management strategy under the three working conditions to obtain the optimal threshold. Finally, under WTVC and combined conditions, the optimized recognizer is used to identify the conditions in real time and call the optimal rule threshold, and the sliding average filter is used to filter the fuel cell output power in real time, which finally realizes the adaptive control. The simulation results show that compared with the conventional rule-based energy management strategy, the number of fuel cell start–stops is reduced. The equivalent hydrogen consumption is reduced by 7.04% and 4.76%, respectively. Full article

Properly managing aquatic organisms is crucial, including protecting endemic species and controlling invasive species. From a circular economy perspective, the sustainable use of aquatic species as a source of bioactive molecules is an area that is increasingly being explored. This includes the use of non-edible portions of seafood, which could pose considerable risks to the environment due to current methods of disposal. Therefore, it is of paramount importance to ensure that the exploitation of these resources does not result in the transfer of pollutants to the final product. This study analyzed two types of non-edible parts from the crayfish Procambarus clarkii: the abdominal portion of the exoskeleton (AbE) and the whole exoskeleton (WE), including the cephalothorax. These portions could potentially be utilized in the context of eradication activities regulated by local authorities. A screening analysis of four classes of pollutants, including pesticides, per- and polyfluoroalkyl substances (PFAS), phthalic acid esters (PAEs), and trace elements (TEs), was performed. The only analytes detected were TEs, and significant differences in the contamination profile were found between AbE and WE. Nevertheless, the levels recorded were comparable to or lower than those reported in the literature and below the maximum levels allowed in the current European legislation for food, suggesting that their potential use is legally permitted. In terms of scalability, the utilization of the entire non-edible P. clarkii portion would represent a sustainable solution for the reuse of waste products. Full article

The escalating evolution of aquaculture has wielded a profound and far-reaching impact on regional sustainable development, ecological equilibrium, and food security. Currently, most aquaculture mapping efforts mainly focus on coastal aquaculture ponds rather than diverse inland aquaculture areas. Recognizing all types of aquaculture areas and accurately classifying different types of aquaculture areas remains a challenge. Here, on the basis of the Google Earth Engine (GEE) and the time-series Sentinel-1 and -2 data, we developed a novel hierarchical framework extraction method for mapping fine inland aquaculture areas (aquaculture ponds + rice-crawfish fields) by employing distinct phenological disparities within two temporal windows (T1 and T2) in Qianjiang, so-called “Home of Chinese Crawfish”. Simultaneously, we evaluated the classification performance of four distinct machine learning classifiers, namely Random Forest (RF), Support Vector Machine (SVM), Classification and Regression Trees (CART), and Gradient Boosting (GTB), as well as 11 feature combinations. Following an exhaustive comparative analysis, we selected the optimal machine learning classifier (i.e., the RF classifier) and the optimal feature combination (i.e., feature combination after an automated feature selection method) to classify the aquaculture areas with high accuracy. The results underscore the robustness of the proposed methodology, achieving an outstanding overall accuracy of 93.8%, with an F1 score of 0.94 for aquaculture. The result indicates that an area of 214.6 ± 10.5 km² of rice-crawfish fields, constituting approximately 83% of the entire aquaculture area in Qianjiang, followed by aquaculture ponds (44.3 ± 10.7 km², 17%). The proposed hierarchical framework, based on significant phenological characteristics of varied aquaculture types, provides a new approach to monitoring inland freshwater aquaculture in China and other regions of the world. Full article

Historically, there has been little success with the captive breeding of American alligators (Alligator mississippiensis) for both commercial and conservative purposes. This study, conducted at Golden Ranch in Gheens, LA, between 2016 and 2022, utilized a newly formulated commercial feed and practical dietary supplementation (crawfish waste products) to enhance egg production, fertility, and hatch rates. The primary focus of this study was to compare the outcome of this captive breeding program at Golden Ranch with a program conducted at Rockefeller Refuge (RR) between 1979 and 1984. Notable success was achieved in terms of reproductive performance in comparison to the captive breeding program conducted at Rockefeller Refuge. In this study, 16.1 hatchlings were produced per nest on Golden Ranch from captive breeders. Additionally, when wild nests from Golden Ranch were incubated in the same controlled environmental chambers, they produced an average of 16.3 hatchlings per nest. This comparison emphasizes the similarity in egg production between captive-bred A. mississippiensis and their wild counterparts. The findings of this study suggest that a closed farming system for A. mississippiensis can be established by employing captive breeders derived from artificially incubated wild eggs. Furthermore, American alligators raised in controlled environmental chambers during their initial three years of life demonstrated adaptability to captive conditions and tolerated stocking rates associated with farming conditions and served as breeding stock. Full article

Crawfish can be easily spoiled due to their rich nutrition and high water content, which is difficult to preserve. In this study, the dominant spoilage organisms in crawfish which were stored at 4 °C in vacuum packaging were identified by high-throughput sequencing technology; after sequencing the full-length 16S rRNA gene, the changes in the bacterial community structure, diversity and quality (texture, flavor, etc.) were analyzed. Our results reflected that the specific spoilage organisms (SSOs) of crawfish were Aeromonas sobria, Shewanella putrefaciens, Trichococcus pasteurii and Enterococcus aquimarinus, since their abundances significantly increased after being stored for 12 days at 4 °C under vacuum conditions. At the same time, the abundance and diversity of the microbial community decreased with storage time, which was related to the rapid growth of the dominant spoilage organisms and the inhibition of other kinds of microorganisms at the end of the spoilage stage. Function prediction results showed that the gene which contributed to metabolism influenced the spoilage process. Moreover, the decline in texture of crawfish was negatively correlated to the richness of SSOs; this may be because SSOs can produce alkaline proteases to degrade the myofibrillar protein. On the contrary, the unpleasant flavor of crawfish, resulting from volatile flavor compounds such as S-containing compounds and APEOs, etc., is negatively correlated to the richness of SSOs, due to the metabolism of SSOs by secondary metabolites such as terpenoids, polyketides and lips, which can lead to decarboxylation, deamination and enzymatic oxidation. These results are very important to achieve the purpose of targeted inhibition of crawfish spoilage at 4 °C in vacuum packaging. Full article

The main challenge of astaxanthin extraction is to provide an eco-friendly method of extraction instead of chemical methods that harm human health. This study provided an eco-friendly method for astaxanthin extraction using two bacterial and fungal probiotics (Bifidobacterium lactis, Lactobacillus lactis, Candida utilis, and Saccharomyces cerevisiae, respectively) and determined the astaxanthin concentration by high-performance liquid chromatography (HPLC) analysis. The results showed that the highest concentration was obtained by S. cerevisiae (45.69 µg/g). Several biological tests were done on the exoskeleton containing astaxanthin of crawfish. Antifungal activity was effective against C. utilis (inhibition zone is 12.3 ± 0.5 mm). The scavenging percentage of 2,2-diphenyl-1-picrylhydrazyl (DPPH scavenging percentage) was 72.1% at 1000 µg/mL concentration of exoskeleton containing astaxanthin. The Hemolysis inhibition percentage was 65% at the same concentration used previously. Furthermore, the IC50 value of human liver cancer cell line (HepG2), human hepatocellular carcinoma (HCT), and breast cancer cell line MCF-7 were 24 µg/mL, 11 µg/mL, and 9.5 µg/mL, respectively. The least cell viability percentage was 19% (using breast cancer cell line (MCF-7)) at 100 µg/mL of exoskeleton containing astaxanthin. Thus, using microorganisms can be an alternative and promising way of astaxanthin extraction. Furthermore, purification of extracted astaxanthin is essential for medical applications. Full article

Aquatic products have an important role in global agriculture, but the challenges associated with preservation have limited their marketability. Essential oil (EO), such as sweet orange oil (SOEO), has been widely used for preservation due to its excellent antibacterial ability. However, the volatilization of EO limits its application in food preservation. In this study, SOEO was extracted from sweet orange peel by steam distillation and then stored in microcapsules. The components of the microcapsules were as follows: the porous starch was chosen as an adsorbed substrate to store SOEO (PS/SOEO), and sodium alginate (SA) and chitosan (CMCS) were used as shell material to delay the volatilization of SOEO using the sharp pore coagulation method. Our results showed that the main antibacterial ingredients in SOEO were aldehydes (33.93%) and d-limonene (15.38%). The microcapsules were of an irregular shape (oval), and the size of the microcapsules was 1.2 $\pm$ 0.1 cm as measured by a digital micrometer. Scanning electron microscopy (SEM) results showed that there were a lot of pores on the surface of the starch after modification, but sodium alginate and chitosan could well encapsulate these pores. The results of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis also showed that SOEO was successful encapsulated into the porous starch. The results of compression test and releasing kinetics studies suggested that CMCS and SA improved the mechanical and slow-releasing ability of SOEO microcapsules. The best antibacterial performance was obtained when 0.8 g of SOEO microcapsules was added. Finally, the shelf life of crawfish could be extended to 6 days by SOEO microcapsule (1/10 g, SOEO microcapsule/crawfish) under room temperature. These results provide a systematic understanding of the antibacterial capabilities of sweet orange essential oil microcapsules, which can contribute to the development of preservation methods for aquatic products. Full article

The aim of our study was to describe the balance between health benefits and risks associated with the consumption of crawfish and nine fish species from lake Trasimeno. We thus determined both fatty acid profiles (particularly, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids) and chemical pollutants (some polychlorinated biphenyls, pesticides, and heavy metals) in fish muscle tissues. The contents of all fatty acids varied significantly among species. Sand smelt, carp, and tench, which have a high fat content, contained considerable amounts of EPA and DHA; lean fish, like perch, pike, and largemouth bass, which have relatively high percentages of the predominant n-3 fatty acids EPA and DHA, showed lower amounts of these fatty acids because of their low lipid contents. Some species contributed strongly to the Dietary Reference Intake (RDI) of EPA and DHA. The contribution of lean fish to the RDI of EPA and DHA was more limited. The concentrations of all contaminants in fish muscle tissues were lower than the regulatory limits, demonstrating the safety of the environmental conditions of the lake. The contribution to health-based reference values and benefit–risk quotients indicated that the health benefits of consumption of fish from lake Trasimeno outweigh the potential risks. Full article

qRT-PCR is a widely used technique for rapid and accurate quantification of gene expression data. The use of reference genes for normalization of the expression levels is crucial for accuracy. Several studies have shown that there is no perfect reference gene that is appropriate for use in all experimental conditions, and research on suitable reference genes in red swamp crawfish (Procambarus clarkii) is particularly scarce. In this study, eight commonly used crustacean reference genes were chosen from P. clarkii transcriptome data and investigated as potential candidates for normalization of qRT-PCR data. Expression of these genes under different experimental conditions was examined by qRT-PCR, and the stability of their expression was evaluated using three commonly used statistical algorithms, geNorm, NormFinder and BestKeeper. A final comprehensive ranking determined that EIF and 18S were the optimal reference genes for expression data from different tissues, while TBP and EIF were optimal for expression data from different ovarian developmental stages. To our knowledge, this is the first systematic analysis of reference genes for normalization of qRT-PCR data in P. clarkii. These results will facilitate more accurate and reliable expression studies of this and other crustacean species. Full article

2,4-dichlorophenoxyacetic acid and monosodium methanearsonate are often sold in commercial mixtures. Bioconcentration studies have been performed for each of these herbicides individually, but little information exists concerning long-term exposure to a mixture of these herbicides. The following study examined the uptake of arsenic in crawfish after long-term exposure to this mixture, and the health risks associated with consumption of these crawfish. Bioconcentration and depuration experiments using a 50:50 by concentration mixture of the two herbicides, with and without surfactant, were performed to quantify how much arsenic is concentrated in the edible tissue of the crawfish. Of the three tissues (muscle, gill, and hepatopancreas) sampled hepatopancreas bioconcentrated the highest amount of arsenic. Surfactant significantly reduced this uptake but did not affect bioconcentration of arsenic into other tissues. Surfactant had no effect on depuration of arsenic from any of the tissues. Cooking lowered hepatopancreatic arsenic content, possibly as a result of structural changes in the hepatopancreas. Assessment of the human health risk associated with consuming these crawfish showed an exposure dose at the high end of consumption that was approximately twice the reference dose for arsenic. Cancer risks were averaged at approximately 7 extra tumors in a population of 10,000 and 6 extra tumors in a population of 10,000 resulting from a lifetime consumption of crawfish exposed to the herbicide mixture without and with surfactant, respectively. Full article

2,4-dichlorophenoxyacetic acid and monosodium methanearsonate are often sold in commercial herbicide mixtures. Toxicity studies have been performed for each herbicide individually, but there is a dearth of information concerning the toxicity of these herbicides in a mixture. The following study examined the toxicity of a mixture of these two herbicides in the red swamp crawfish, Procambarus clarkii. 96-hour acute toxicity assays were performed to determine whether surfactant significantly altered the toxicity of these herbicides individually or in combination. Marking’s additive index was calculated to identify the interactions of the herbicide mixture. Surfactant was observed to significantly increase the toxicity of 2,4-dichlorophenoxyacetic acid and the toxicity of the herbicide mixture. The herbicide mixture alone displayed half the toxicity of the individual herbicides, but the mixture with surfactant was twice as toxic as the individual herbicides. The synergistic action of surfactant may be attributed to increased pesticide absorption across biological membranes. 2,4-dichlorophenoxyacetic acid and surfactant may also compromise gill function, increasing the sensitivity of the crawfish to herbicide toxicity. The antagonistic effects of the herbicide mixture in the absence of surfactant may be caused by competition of both herbicides for the same sites of activity. Full article