Sailfish generate foraging opportunities for seabirds in multi-species predator aggregations.

While various marine predators form associations, the most commonly studied are those between subsurface predators and seabirds, with gulls, shearwaters or terns frequently co-occurring with dolphins, billfish or tuna. However, the mechanisms underlying these associations remain poorly understood. Three hypotheses have been proposed to explain the prevalence of these associations: (1) subsurface predators herd prey to the surface and make prey accessible to birds, (2) subsurface predators damage prey close to the surface and thereby provide food scraps to birds, and (3) attacks of underwater predators lower the cohesion of prey groups and thereby their collective defences making the prey easier to be captured by birds. Using drone footage, we investigated the interaction between Indo-Pacific sailfish (Istiophorus platypterus) and terns (Onychoprion sp.) preying on schooling fish off the eastern coast of the Malaysian peninsula. Through spatio-temporal analysis of the hunting behaviour of the two predatory species and direct measures of prey cohesion we showed that terns attacked when school cohesion was low, and that this decrease in cohesion was frequently caused by sailfish attacks. Therefore, we propose that sailfish created a by-product benefit for the bird species, lending support to the hypothesis that lowering cohesion can facilitate associations between subsurface predators and seabirds.

An improved Differential evolution with Sailfish optimizer (DESFO) for handling feature selection problem.

As a preprocessing for machine learning and data mining, Feature Selection plays an important role. Feature selection aims to streamline high-dimensional data by eliminating irrelevant and redundant features, which reduces the potential curse of dimensionality of a given large dataset. When working with datasets containing many features, algorithms that aim to identify the most valuable features to improve dataset accuracy may encounter difficulties because of local optima. Many studies have been conducted to solve this problem. One of the solutions is to use meta-heuristic techniques. This paper presents a combination of the Differential evolution and the sailfish optimizer algorithms (DESFO) to tackle the feature selection problem. To assess the effectiveness of the proposed algorithm, a comparison between Differential Evolution, sailfish optimizer, and nine other modern algorithms, including different optimization algorithms, is presented. The evaluation used Random forest and key nearest neighbors as quality measures. The experimental results show that the proposed algorithm is a superior algorithm compared to others. It significantly impacts high classification accuracy, achieving 85.7% with the Random Forest classifier and 100% with the Key Nearest Neighbors classifier across 14 multi-scale benchmarks. According to fitness values, it gained 71% with the Random forest and 85.7% with the Key Nearest Neighbors classifiers.

SJFO: Sail Jelly Fish Optimization enabled VM migration with DRNN-based prediction for load balancing in cloud computing.

The dynamic workload is evenly distributed among all nodes using balancing methods like hosts or VMs. Load Balancing as a Service (LBaaS) is another name for load balancing in the cloud. In this research work, the load is balanced by the application of Virtual Machine (VM) migration carried out by proposed Sail Jelly Fish Optimization (SJFO). The SJFO is formed by combining Sail Fish Optimizer (SFO) and Jellyfish Search (JS) optimizer. In the Cloud model, many Physical Machines (PMs) are present, where these PMs are comprised of many VMs. Each VM has many tasks, and these tasks depend on various parameters like Central Processing Unit (CPU), memory, Million Instructions per Second (MIPS), capacity, total number of processing entities, as well as bandwidth. Here, the load is predicted by Deep Recurrent Neural Network (DRNN) and this predicted load is compared with a threshold value, where VM migration is done based on predicted values. Furthermore, the performance of SJFO-VM is analysed using the metrics like capacity, load, and resource utilization. The proposed method shows better performance with a superior capacity of 0.598, an inferior load of 0.089, and an inferior resource utilization of 0.257.

A secure worst elite sailfish optimizer based routing and deep learning for black hole attack detection.

The Wireless Sensor Network (WSN) is susceptible to two kinds of attacks, namely active attack and passive attack. In an active attack, the attacker directly communicates with the target system or network. In contrast, in passive attack, the attacker is in indirect contact with the network. To preserve the functionality and dependability of wireless sensor networks, this research has been conducted recently to detect and mitigate the black hole attacks. In this research, a Deep learning (DL) based black hole attack detection model is designed. The WSN simulation is the beginning stage of this process. Moreover, routing is the key process, where the data is passed to the base station (BS) via the shortest and finest route. The proposed Worst Elite Sailfish Optimization (WESFO) is utilized for routing. Moreover, black hole attack detection is performed in the BS. The Auto Encoder (AE) is employed in attack detection, which is trained with the use of the proposed WESFO algorithm. Additionally, the proposed model is validated in terms of delay, Packet Delivery Rate (PDR), throughput, False-Negative Rate (FNR), and False-Positive Rate (FPR) parameters with the corresponding outcomes like 25.64 s, 94.83%, 119.3, 0.084, and 0.135 are obtained.

Seasonally mediated niche partitioning in a vertically compressed pelagic predator guild.

Niche partitioning among closely related, sympatric species is a fundamental concept in ecology, and its mechanisms are of broad interest for understanding ecosystem functioning and predicting the impacts of human-driven environmental change. However, identifying mechanisms by which top marine predators partition available resources has been especially challenging given the difficulty of quantifying resource use of large pelagic animals. In the eastern tropical Pacific (ETP), three large, highly mobile and ecologically similar pelagic predators (blue marlin (Makaira nigricans), black marlin (Istiompax indica) and sailfish (Istiophorus platypterus)) coexist in a vertically compressed habitat. To evaluate each species' ecological niche, we leveraged a decade of recreational fisheries data, multi-year satellite tracking with high-resolution dive data, and stable isotope analysis. Fishery interaction and telemetry-based three-dimensional seasonal utilization distributions suggested high spatial and temporal overlap among species; however, seasonal and diel variability in diving behaviour produced spatial partitioning, leading to low trophic overlap among species. Expanding oxygen minimum zones will reduce the available vertical habitat within predator guilds, likely leading to increases in interspecific competition. Thus, understanding the mechanisms of habitat partitioning among predators in the vertically compressed ETP can provide insight into how predators in other ocean regions may respond to vertically limited habitats.

SDN-IoT: SDN-based efficient clustering scheme for IoT using improved Sailfish optimization algorithm.

The Internet of Things (IoT) includes billions of different devices and various applications that generate a huge amount of data. Due to inherent resource limitations, reliable and robust data transmission for a huge number of heterogenous devices is one of the most critical issues for IoT. Therefore, cluster-based data transmission is appropriate for IoT applications as it promotes network lifetime and scalability. On the other hand, Software Defined Network (SDN) architecture improves flexibility and makes the IoT respond appropriately to the heterogeneity. This article proposes an SDN-based efficient clustering scheme for IoT using the Improved Sailfish optimization (ISFO) algorithm. In the proposed model, clustering of IoT devices is performed using the ISFO model and the model is installed on the SDN controller to manage the Cluster Head (CH) nodes of IoT devices. The performance evaluation of the proposed model was performed based on two scenarios with 150 and 300 nodes. The results show that for 150 nodes ISFO model in comparison with LEACH, LEACH-E reduced energy consumption by about 21.42% and 17.28%. For 300 ISFO nodes compared to LEACH, LEACH-E reduced energy consumption by about 37.84% and 27.23%.

Patrolling the border: Billfish exploit the hypoxic boundary created by the world's largest oxygen minimum zone.

Pelagic predators must contend with low prey densities that are irregularly distributed and dynamic in space and time. Based on satellite imagery and telemetry data, many pelagic predators will concentrate horizontal movements on ephemeral surface fronts-gradients between water masses-because of enhanced local productivity and increased forage fish densities. Vertical fronts (e.g. thermoclines, oxyclines) can be spatially and temporally persistent, and aggregate lower trophic level and diel vertically migrating organisms due to sharp changes in temperature, water density or available oxygen. Thus, vertical fronts represent a stable and potentially energy rich habitat feature for diving pelagic predators but remain little explored in their capacity to enhance foraging opportunities. Here, we use a novel suite of high-resolution biologging data, including in situ derived oxygen saturation and video, to document how two top predators in the pelagic ecosystem exploit the vertical fronts created by the oxygen minimum zone of the eastern tropical Pacific. Prey search behaviour was dependent on dive shape, and significantly increased near the thermocline and hypoxic boundary for blue marlin Makaira nigricans and sailfish Istiophorus platypterus, respectively. Further, we identify a behaviour not yet reported for pelagic predators, whereby the predator repeatedly dives below the thermocline and hypoxic boundary (and by extension, below the prey). We hypothesize this behaviour is used to ambush prey concentrated at the boundaries from below. We describe how habitat fronts created by low oxygen environments can influence pelagic ecosystems, which will become increasingly important to understand in the context of global change and expanding oxygen minimum zones. We anticipate that our findings are shared among many pelagic predators where strong vertical fronts occur, and additional high-resolution tagging is warranted to confirm this.

Energy-Efficient Clustering and Routing Using ASFO and a Cross-Layer-Based Expedient Routing Protocol for Wireless Sensor Networks.

Today's critical goals in sensor network research are extending the lifetime of wireless sensor networks (WSNs) and lowering power consumption. A WSN necessitates the use of energy-efficient communication networks. Clustering, storage, communication capacity, high configuration complexity, low communication speed, and limited computation are also some of the energy limitations of WSNs. Moreover, cluster head selection remains problematic for WSN energy minimization. Sensor nodes (SNs) are clustered in this work using the Adaptive Sailfish Optimization (ASFO) algorithm with K-medoids. The primary purpose of research is to optimize the selection of cluster heads through energy stabilization, distance reduction, and latency minimization between nodes. Because of these constraints, achieving optimal energy resource utilization is an essential problem in WSNs. An energy-efficient cross-layer-based expedient routing protocol (E-CERP) is used to determine the shortest route, dynamically minimizing network overhead. The proposed method is used to evaluate the packet delivery ratio (PDR), packet delay, throughput, power consumption, network lifetime, packet loss rate, and error estimation, and the results were superior to existing methods. PDR (100%), packet delay (0.05 s), throughput (0.99 Mbps), power consumption (1.97 mJ), network lifespan (5908 rounds), and PLR (0.5%) for 100 nodes are the performance results for quality-of-service parameters.

Exponential Sailfish Optimizer-based generative adversarial network for image annotation on natural scene images.

Generally, automatic image annotation can offer semantic graphics for recognizing image contents, and it creates a base for devising various techniques, which can search images in a huge dataset. Although most existing techniques mainly focus on resolving annotation issues through sculpting tag semantic information and visual image content, it ignores additional information, like picture positions and descriptions. The established Exponential Sailfish Optimizer-based Generative Adversarial Networks are therefore used to provide an efficient approach for image annotation (ESFO-based GAN). By combining Exponentially Weighted Moving Average (EWMA) and Sailfish Optimizer (SFO), the ESFO is a newly created design that is used to train the GAN classifier. Additionally, the Grabcut is presented to successfully do image annotation by extracting the background and foreground images. Additionally, DeepJoint segmentation is used to divide apart the images based on the background image that was extracted. Finally, image annotation is successfully accomplished with the aid of GAN. As a result, image annotation uses the produced ESFO-based GAN's subsequent results. The developed approach exhibited enhanced outcomes with maximum F-Measure of 98.37%, maximum precision of 97.02%, and maximal recall of 96.64%, respectively, using the flicker dataset.

Lacunae rostralis: A new structure on the rostrum of sailfish Istiophorus platypterus.

Recent comparative studies of billfishes (Istiophoridae and Xiphiidae) have provided evidence of differences in the form and function of the rostra (bill) among species. Here, we report the discovery of a new structure, lacuna rostralis, on the rostra of sailfish Istiophorus platypterus, which is absent on the rostra of swordfish Xiphias gladius, striped marlin Kajikia audax and blue marlin Makaira nigricans. The lacunae rostralis are small cavities that contain teeth. They were found on the ventral rostrum surface of all I. platypterus specimens examined and dorsally in half of them. Ventrally, the lacunae rostralis were most prominent in the mid-section of the rostrum. Dorsally, they occurred closer to the tip. The density of lacunae rostralis increased towards the rostrum tip but, because they are smaller in size, the percentage of rostrum coverage decreased. The teeth located within the lacunae rostralis were found to be different in size, location and orientation from the previously identified micro-teeth of billfish. We propose two potential functions of the lacunae rostralis that both relate to the use of the bill in feeding: mechanoreception of prey before tapping it with the bill and more efficient prey handling via the creation of suction, or physical grip.

CAViaR-WS-based HAN: conditional autoregressive value at risk-water sailfish-based hierarchical attention network for emotion classification in COVID-19 text review data.

The Corona Virus Disease-2019 (COVID-19) pandemic has made a remarkable impact on economies and societies worldwide. With numerous procedures of social distancing and lockdowns, it becomes essential to know people's emotional responses on a very large scale. Thus, an effective emotion classification approach is developed using the proposed Conditional Autoregressive Value at Risk-Water Sailfish-based Hierarchical Attention Network (CAViaR-WS-based HAN) for classifying the emotions in the COVID-19 text review data. The proposed approach, named CAViaR-WS, is designed by the incorporation of Conditional Autoregressive Value at Risk-Sail Fish (CAViaR-SF) and Water Cycle Algorithm (WCA). Here, the significant features, such as mean, variance, entropy, Term Frequency-Inverse Document Frequency (TF-IDF), SentiWordNet features, and spam word-based features, are extracted to further processing. Based on the extracted features, feature fusion is accomplished using the RideNN. In addition, CAViaR-SF-based GAN is used to perform the spam classification, and then, the emotion classification is carried out using Hierarchal Attention Networks (HAN), where the training procedure of HAN is performed using proposed CAViaR-WS. Furthermore, the developed CAViaR-WS-based HAN offers effective performance results concerning precision, recall, and f-measure with the maximal values of 0.937, 0.958, and 0.948, respectively.

An Optimized Nature-Inspired Metaheuristic Algorithm for Application Mapping in 2D-NoC.

Mapping application task graphs on intellectual property (IP) cores into network-on-chip (NoC) is a non-deterministic polynomial-time hard problem. The evolution of network performance mainly depends on an effective and efficient mapping technique and the optimization of performance and cost metrics. These metrics mainly include power, reliability, area, thermal distribution and delay. A state-of-the-art mapping technique for NoC is introduced with the name of sailfish optimization algorithm (SFOA). The proposed algorithm minimizes the power dissipation of NoC via an empirical base applying a shared k-nearest neighbor clustering approach, and it gives quicker mapping over six considered standard benchmarks. The experimental results indicate that the proposed techniques outperform other existing nature-inspired metaheuristic approaches, especially in large application task graphs.

The complete mitochondrial genome of the Capsaloides cristatus (Platyhelminthes, Monogenea), a pathogen of the sailfish (Istiophorus platypterus).

This study reports the complete mitochondrial genome of the Capsaloides cristatus (Monogenea: Capsalidae) collected from the gill lamella of Istiophorus platypterus. The total length of the mitogenome was 13,948 bp, containing 12 typical platyhelminthic protein-coding genes, 22 tRNA genes, 2 rRNA genes and a putative non-coding region, with the atp8 gene being absent. The total A + T content was 65.99%, which was significantly higher than that of the C + G content (34.01%). There were two kinds of start codons (ATG and GTG) and three kinds of terminated codons (TAA, TAG and TGA) in the 12 protein-coding genes. Phylogentic analysis revealed close relationships among the genera Capsaloides, Capsala, Benedenia and Neobenedenia with high bootstrap value supported. This study will provide useful molecular data for a better understanding of the species identification and phylogenetic position of C. cristatus.

The Genomes of Two Billfishes Provide Insights into the Evolution of Endothermy in Teleosts.

Endothermy is a typical convergent phenomenon which has evolved independently at least eight times in vertebrates, and is of significant advantage to organisms in extending their niches. However, how vertebrates other than mammals or birds, especially teleosts, achieve endothermy has not previously been fully understood. In this study, we sequenced the genomes of two billfishes (swordfish and sailfish), members of a representative lineage of endothermic teleosts. Convergent amino acid replacements were observed in proteins related to heat production and the visual system in two endothermic teleost lineages, billfishes and tunas. The billfish-specific genetic innovations were found to be associated with heat exchange, thermoregulation, and the specialized morphology, including elongated bill, enlarged dorsal fin in sailfish and loss of the pelvic fin in swordfish.

Linking hunting weaponry to attack strategies in sailfish and striped marlin.

Linking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) when attacking schooling sardine prey. Behavioural results from high-speed videos showed that sailfish and striped marlin both regularly made rostrum contact with prey but displayed distinct strategies. Marlin used high-speed dashes, breaking schools apart, often contacting prey incidentally or tapping at isolated prey with their rostra; while sailfish used their rostra more frequently and tended to use a slower, less disruptive approach with more horizontal rostral slashes on cohesive prey schools. Capture success per attack was similar between species, but striped marlin had higher capture rates per minute. The rostra of both species are covered with micro-teeth, and micro-CT imaging showed that species did not differ in average micro-tooth length, but sailfish had a higher density of micro-teeth on the dorsal and ventral sides of their rostra and a higher amount of micro-teeth regrowth, suggesting a greater amount of rostrum use is associated with more investment in micro-teeth. Our analysis shows that the rostra of billfish are used in distinct ways and we discuss our results in the broader context of relationships between morphological and behavioural feeding adaptations across species.

The Evolution of Lateralization in Group Hunting Sailfish.

Lateralization is widespread throughout the animal kingdom [1-7] and can increase task efficiency via shortening reaction times and saving on neural tissue [8-16]. However, lateralization might be costly because it increases predictability [17-21]. In predator-prey interactions, for example, predators might increase capture success because of specialization in a lateralized attack, but at the cost of increased predictability to their prey, constraining the evolution of lateralization. One unexplored mechanism for evading such costs is group hunting: this would allow individual-level specialization, while still allowing for group-level unpredictability. We investigated this mechanism in group hunting sailfish, Istiophorus platypterus, attacking schooling sardines, Sardinella aurita. During these attacks, sailfish alternate in attacking the prey using their elongated bills to slash or tap the prey [22-24]. This rapid bill movement is either leftward or rightward. Using behavioral observations of identifiable individual sailfish hunting in groups, we provide evidence for individual-level attack lateralization in sailfish. More strongly lateralized individuals had a higher capture success. Further evidence of lateralization comes from morphological analyses of sailfish bills that show strong evidence of one-sided micro-teeth abrasions. Finally, we show that attacks by single sailfish are indeed highly predictable, but predictability rapidly declines with increasing group size because of a lack of population-level lateralization. Our results present a novel benefit of group hunting: by alternating attacks, individual-level attack lateralization can evolve, without the negative consequences of individual-level predictability. More generally, our results suggest that group hunting in predators might provide more suitable conditions for the evolution of strategy diversity compared to solitary life.

Proto-cooperation: group hunting sailfish improve hunting success by alternating attacks on grouping prey.

We present evidence of a novel form of group hunting. Individual sailfish (Istiophorus platypterus) alternate attacks with other group members on their schooling prey (Sardinella aurita). While only 24% of attacks result in prey capture, multiple prey are injured in 95% of attacks, resulting in an increase of injured fish in the school with the number of attacks. How quickly prey are captured is positively correlated with the level of injury of the school, suggesting that hunters can benefit from other conspecifics' attacks on the prey. To explore this, we built a mathematical model capturing the dynamics of the hunt. We show that group hunting provides major efficiency gains (prey caught per unit time) for individuals in groups of up to 70 members. We also demonstrate that a free riding strategy, where some individuals wait until the prey are sufficiently injured before attacking, is only beneficial if the cost of attacking is high, and only then when waiting times are short. Our findings provide evidence that cooperative benefits can be realized through the facilitative effects of individuals' hunting actions without spatial coordination of attacks. Such 'proto-cooperation' may be the pre-cursor to more complex group-hunting strategies.

AtRTD - a comprehensive reference transcript dataset resource for accurate quantification of transcript-specific expression in Arabidopsis thaliana.

RNA-sequencing (RNA-seq) allows global gene expression analysis at the individual transcript level. Accurate quantification of transcript variants generated by alternative splicing (AS) remains a challenge. We have developed a comprehensive, nonredundant Arabidopsis reference transcript dataset (AtRTD) containing over 74 000 transcripts for use with algorithms to quantify AS transcript isoforms in RNA-seq. The AtRTD was formed by merging transcripts from TAIR10 and novel transcripts identified in an AS discovery project. We have estimated transcript abundance in RNA-seq data using the transcriptome-based alignment-free programmes Sailfish and Salmon and have validated quantification of splicing ratios from RNA-seq by high resolution reverse transcription polymerase chain reaction (HR RT-PCR). Good correlations between splicing ratios from RNA-seq and HR RT-PCR were obtained demonstrating the accuracy of abundances calculated for individual transcripts in RNA-seq. The AtRTD is a resource that will have immediate utility in analysing Arabidopsis RNA-seq data to quantify differential transcript abundance and expression.

Short-term movements and habitat preferences of sailfish, Istiophorus platypterus (Istiophoridae), along the southeast coast of Brazil

Pop-up satellite archival tags (PSATs) were deployed on four sailfish, Istiophorus platypterus, in the coastal waters of Rio de Janeiro State in southeast Brazil during January and February of 2009 (sailfish I and II) and between November 2010 and January 2011 (sailfish III and IV). The total number of days monitored (i.e., time that the tags remained attached) were 12 (sailfish I), 51 (sailfish II), 16 (sailfish III) and 43 days (sailfish IV). The results indicate a clear pattern of vertical habitat utilization with the majority of the time spent concentrated near the uniform sea surface layer occupying a relatively narrow temperature range. Despite the clear preference for epipelagic surface waters, sailfish regularly undertook vertical excursions into deeper waters (>50 m) within three to six hour intervals. "Most Probable Tracks" (estimated from raw geolocations using the state-space Kalman filter model) and linear displacements suggested that tagged sailfish did not move significant distances from the tagging site. In brief, our report provides information regarding the biology of sailfish in the southwestern Atlantic and how vertical distributions during the day and night are influenced by water temperature and how this information can improve sailfish stock assessments in southwestern Atlantic Ocean.

Quatro exemplares de agulhão-vela foram marcados com marcas eletrônicas monitoradas por satélite ('Pop-up satellite archival tags - PSATs') nas águas costeiras do Rio de Janeiro, sudeste do Brasil, durante janeiro e fevereiro de 2009 (agulhão-vela I e II) e entre novembro de 2010 e janeiro de 2011 (agulhão-vela III e IV). O número total de dias monitorados (ou seja, o tempo que as marcas permaneceram implantadas nos peixes) foram 12 (agulhão-vela I), 51 (agulhão-vela II), 16 (agulhão-vela III) e 43 dias (agulhão-vela IV). Os resultados demonstram um padrão claro de utilização do hábitat com a maior parte do tempo despendido predominantemente próximo à superfície do mar ocupando águas com uma faixa de temperatura restrita. Apesar da preferência por águas superficiais, os agulhões frequentemente realizaram mergulhos para águas mais profundas (ca. > 50 m) em intervalos de três a seis horas. A "rota mais provável" estimada a partir dos dados brutos de geolocalização e o modelo 'State-Space Kalman Filter' sugerem que os agulhões marcados não realizaram migrações significativas a partir do local de marcação. Em resumo, nossos resultados apresentam informações sobre a biologia da espécie no Atlântico Sudoeste e como as migrações verticais durante o dia e a noite são influenciadas pela temperatura da água e como essa informação pode auxiliar as avaliações de estoques de agulhão-vela no sudoeste do Atlântico.