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Sander lucioperca represents a potential candidate for aquaculture in Moroccan freshwater, but information concerning its diet and feeding habits is still lacking. This study therefore aims to contribute to the knowledge of the feeding ecology of this invasive species in Al Massira Reservoir, with particular emphasis on seasonal and intraspecific diet variation. Analysis of stomach contents revealed that the pike perch diet consists of various prey items, with an abundance of Lepomis gibbosus. However, S. lucioperca is also an opportunistic predator, capable of consuming other food resources when they become available in its habitat. This opportunistic behavior may account for the successful establishment of this species' population in a large reservoir, despite the coexistence of other carnivorous fish species. The dietary composition indicated a carnivorous diet with considerable seasonal variation. There was no significant sex-related or ontogenetic variation in the diet. The feeding intensity is similar between males and females, as well as across different size classes, but it varies according to the seasons. The results provide fundamental information about the feeding habits of this species, which is used for artificial culture research. [ABSTRACT FROM AUTHOR]

The present study was conducted for the purpose of determining the main feeding aspects of the brushtooth lizardfish Saurida undosquamis. It was carried out from September 2018 till April 2019 in the Northern Gulf of Suez, and from March 2018 to March 2019 in the South-Eastern Mediterranean Sea at Port Said. A total of 1110 specimens were monthly collected from both sites. The analysis of stomachs content showed that S. undosquamis is a carnivorous species, feeding on some of both vertebrates and invertebrates preys. The seasonal variations in diet composition revealed that fish remains were the most dominant food item for both populations; however, not during all seasons. Regarding the intensity of feeding, individuals with stomachs containing food were observed mostly during winter with a percentage of 71.4%, while their maximum percentage was in spring with 80.3% for the Gulf of Suez and the Mediterranean Sea populations, respectively. On the other hand, the degree in fullness followed a different trend for individuals from both populations. The variations of diet composition in relation to size for both populations showed that fish remains were the most abundant food items for specimens of almost all size classes, and the monthly averages of gastro-somatic index indicated that both study sites had fluctuation in values. [ABSTRACT FROM AUTHOR]

Accurately identifying the fish feeding intensity is crucial for timely understanding the feeding demand, dynamically adjusting the feeding strategy, and reducing costs. For the variability and uncontrollability of the pond aquaculture environment, the densities of feeding fish schools aggregating to the feeding point exhibit significant variations. Consequently, different densities of fish schools present inconsistent characteristics in the image, even under the same feeding intensity, making the precise identification of feeding intensity difficult. To tackle this issue, a method for identifying the feeding intensity of pond fish schools based on dual-label and MobileViT-SENet (DL-MobileViT-SENet) was proposed. The fish school images were marked with labels indicating density and feeding intensity to establish the dual-label dataset. Subsequently, a proposed MobileViT-SENet network is trained using the dataset to obtain the dual-label pre-training weight incorporating both fish density and feeding intensity features. Two models are trained to identify density and feeding intensity based on the obtained weight. Finally, a dynamic feeding strategy for fish that integrates biomass, density, and feeding intensity is presented. The proposed method combines the density and feeding intensity labels to enhance the accuracy of identifying the feeding intensity of pond fish schools across various densities, and lays the groundwork for designing a dynamic feeding strategy. It was tested on authentic pond fish school images and yielded an accuracy of 97.95%. This value is superior to these comparison methods, demonstrating that this method can accurately identify the feeding intensity of pond fish and provide support for formulating a dynamic feeding strategy. • A method for identifying fish feeding intensity at different densities is proposed. • To improve feature representation in pond culture, a MobileViT-SENet is introduced. • A dual-label pre-training method is proposed to shorten the model training. • A dynamic feeding strategy for pond fish is provided. [ABSTRACT FROM AUTHOR]

The dietary composition, foraging strategies, and interspecific trophic interactions were identified for four major demersal carnivorous finfishes, namely, croaker Otolithes ruber, hairtail Trichiurus lepturus, threadfin bream Nemipterus japonicus, and lizardfish Saurida undosquamis, along the north‐western part of Bay of Bengal from 2014 to 2016. Two species, Trichiurus lepturus and Saurida undosquamis, were identified as finfish feeders due to the high number of teleost (clupeids and engraulids) prey. One species, Nemipterus japonicus, had a significantly different diet of metapenaeids and charybdids, and was identified as a shellfish feeder. The final species, Otolithes ruber, preyed equally on crustaceans and teleosts, and was identified as a shellfish‐finfish feeder. The feeding activity of all four species was lower during peak spawning periods and tended to increase with maturity. Feeding preferences varied with seasons. The trophic level ranged from 3.49 to 4.01, classifying the four species as medium‐carnivores or meso‐predators. Niche breadth ranged from 0.170 to 0.421, with seasonal and ontogenetic variations. Individual or subgroup specialization was observed on dominant prey, but intraspecific diet variations indicated all four species to be opportunistic predators. There was substantial prey overlap for Saurida undosquamis with Otolithes ruber and Trichiurus lepturus, which increased ontogenetically and coincided with their peak spawning. Sharing of abundant prey resources together with temporal and ontogenetic resource partitioning at intra‐ and interspecific levels possibly lowered dietary competition, thereby facilitating the coexistence of these demersal predators. This study provides new information on feeding interactions from a tropical demersal ecosystem that can be applied for the ecosystem‐based management of trawl fisheries. [ABSTRACT FROM AUTHOR]

Schooling makes it easier for fish to find food objects, increases the intensity of feeding and, as a result, improves food supply. The effect is achieved due to well-developed imitative behavior and stress reduction in schooling fish. Staying in a school increases the duration and frequency of feeding, expands the range of available food items, allows the development of new spatial and food resources, reduces the time spent on restoring feeding behavior after stressful loads due to a change in biotope, threat or attack by a predator, and in other cases. Forming a school makes it possible to overcome the resistance of territorial fish that protect food resources in their home areas. Higher feeding efficiency in a school equally affects both non-predatory and predatory schooling fish. However, being in a school can presumably also lead to increased intra-school food competition. [ABSTRACT FROM AUTHOR]

Glossogobius aureus (Gobiiformes: Gobiidae) is a target fish and widely distributed in the Mekong Delta, from fresh to brackish waters. However, knowledge on its food and feeding ecology is scarce. Therefore, this research was carried out in four sampling sites along the estuarine of Hau River in order to fill this information gap. A total of 742 individual fish was collected monthly using trawl nets from January to December 2020. A combined analysis of the fullness index and Costello graph suggested that this fish species displayed high feeding intensity. The results revealed that G. aureus is a carnivore and its food composition comprised Acetes spp., Actinopterygii, zooplankton, and other preys (e.g. snails and detritus). Acetes spp. is the main food of this species. The diet composition varied with sites but not genders, fish sizes, and seasons. Acetes spp., Actinopterygii and other preys contributed to the spatial variation of food composition. The findings revealed knowledge about the fish feeding ecology, which may propose suitable foods for its aquaculture development.

An accurate and rapid identification of fish feeding intensity can be essential to implement the precise feeding strategies in an industrial recirculating aquaculture system. Feeding intensity can be assessed using single modality indicators, such as water quality, vision, and sound. However, these individual data sources can often provide limited information without the complete picture of feeding behavior. The multimodal data can be expected to incorporate more comprehensive insights, compared with the single modality. Consequently, a more accurate representation of fish feeding intensity can be obtained to reduce some limitations of single modality information. Multi-modal fusion can also offer a novel approach to quantifying the feeding intensity. In this study, a Fish-MulT algorithm was proposed to combine the water quality, sound, and vision data using a Multimodal Transformer algorithm (MulT). Firstly, the feature vectors were extracted from the input water quality, sound, and visual data. Secondly, a Multimodal Transfer Module (MMTM) was employed to fuse the input feature vectors. Adaptive weights were then assigned to the three modalities after fusion. Lastly, the cross-modal transformer of each modal branch in the MulT algorithm was optimized to reduce the number of required transformers from 2 to 1. Furthermore, 1293 sets of threemodality data were collected in the experiment, with 70% used as the training set, 15% as the validation set, and the remaining 15% as the test set. The dataset was classified into four categories, according to the feeding intensity: "strong", "medium", "weak", and "none". The improved model was then evaluated using the collected dataset. Experimental results demonstrate that the Fish-MulT algorithm improved the accuracy of the fish feeding intensity identification from 93.30% to 95.36%, while reducing the number of parameters by 38%, compared with the MulT. Moreover, there were significant improvements in the accuracy, compared with the water quality, sound, and vision data, with the increases of 68.56%, 21.65%, and 3.61%, respectively. An ablation test of the added MMTM module and adaptive weight was also conducted during this time. The addition of both the MMTM module and adaptive weight led to the most significant improvement in the accuracy (up to 95.36%). A substantial improvement was achieved in the recognition accuracy, compared with the single modality. As a result, the Fish-MulT algorithm can be employed to develop precise feeding strategies. The finding can provide technical support to intelligent feeding systems. [ABSTRACT FROM AUTHOR]

Glossogobius aureus (Gobiiformes: Gobiidae) is a target fish and widely distributed in the Mekong Delta, from fresh to brackish waters. However, knowledge on its food and feeding ecology is scarce. Therefore, this research was carried out in four sampling sites along the estuarine of Hau River in order to fill this information gap. A total of 742 individual fish was collected monthly using trawl nets from January to December 2020. A combined analysis of the fullness index and Costello graph suggested that this fish species displayed high feeding intensity. The results revealed that G. aureus is a carnivore and its food composition comprised Acetes spp., Actinopterygii, zooplankton, and other preys (e.g. snails and detritus). Acetes spp. is the main food of this species. The diet composition varied with sites but not genders, fish sizes, and seasons. Acetes spp., Actinopterygii and other preys contributed to the spatial variation of food composition. The findings revealed knowledge about the fish feeding ecology, which may propose suitable foods for its aquaculture development. [ABSTRACT FROM AUTHOR]

Diet composition and feeding strategies of deep-sea caridean shrimp Heterocarpus woodmasoni Alcock,1901 are described from gut contents of 4,116 specimens collected from the southwestern coast of India. Knowledge of the species diet plays a prime effect on its biological aspects and its role in the ecological energetics of the community. All the analyses were performed in accordance with ecological (season) and biological factors (sex, size, and gonadal stages). The species was found to prey on diversified components such as detritus, foraminiferans, other crustaceans, molluscs, echinoderms, and fishes in their declining order of preponderance. Multivariate analysis of variance showed a significant difference (P <0.05) in the diet components according to the combination of sex along with season and gonadal stages. Values of the gastro-somatic index (GSI) showed a positive correlation with feeding activity, and its intensity. GSI, feeding intensity, and activity reached their peak values during the post-monsoon season. High vacuity index was recorded in almost all conditions, which is a highlighted feature of this species. These observations provide fundamental information on the feeding pattern of H. woodmasoni , which aims to develop suitable fishing strategies in the future. [ABSTRACT FROM AUTHOR]

The food and feeding habits of Johnius elongatus collected from Ratnagiri coast, Maharashtra, India for a period of 10 months (December 2021 to October 2022) were studied and the present investigation was based on 266 specimens. Both fish and crustaceans dominated the food items in the gut. The crustaceans were identified as the main food item followed by teleost fishes. The species was observed to be a macrophagous carnivore. Among crustaceans the main food items were shrimp, mantis shrimp, acetes and crabs. The feeding intensity was more in February, December and October whereas, it was observed to be moderate in the month of August, September, March and February and poor during January, May and April. GaSI was found highest during December and lowest in April. [ABSTRACT FROM AUTHOR]

The feeding spectrum of and the intensity of the diet consumption by Barents sea skates (Amblyraja radiata, A. hyperborea, Dipturus batis, Rajella fyllae, and Bathyraja spinicauda) have been studied in 2004–2021. The food spectrum of skates is characterized by great diversity; the most abundant are demersal fish species (Pisces) and crustaceans (Crustacea). Food objects and their size composition differ in different size groups of skates. Small-sized individuals consume small benthic invertebrate organisms; however their growth is associated with an increase in their diet of the proportion of large objects, various species of fish and crustaceans. The average annual grazing of commercial aquatic species by skates is at the level of 26.1 thousand tons; the main prey objects are the capelin Mallotus villosus and the northern prawn Pandalus borealis. [ABSTRACT FROM AUTHOR]

Data on feeding of fish are presented collected in the western Chukchi Sea aboard RV «Professor Levanidov» and in the eastern Chukchi Sea aboard RV «Ocean Starr» in August-September, 2019. The feeding was different by areas of the sea and reflected regional features of food base. Copepods and euphausiids were the main components of the diet, though their ratio varied. In the western Chukchi Sea, arctic cod and walleye pollock (40–70 cm) were the main consumers of food resources and consumed on average 3.85 and 8.38 t/km2 per day, respectively. The diet of walleye pollock included fish (4.05 t/km2 . day) and zooplankton (3.01 t/km2 . day, mostly euphausiids — 2.60 t/km2 . day). Arctic cod consumed predominantly zooplankton (3.00 t/km2 . day, mostly copepods — 1.27 t/km2 . day, but also small- and medium-sized species). The total stock of net zooplankton (55.2 t/km2 ) exceeded in 7 times daily consumption of zooplankton. Coelenterates, arrowworms, other plankton species, benthic species, and small-sized nekton were consumed by fish poorly. Daily food ration of arctic cod and walleye pollock was estimated as 7.4–9.4 % and 3.4–4.7 % of their body weight, respectively, so the food supply of these species in the western Chukchi Sea was quite sufficient in 2019. In the eastern Chukchi Sea, the diet of juveniles of walleye pollock, sand lance and arctic cod included mainly copepods (50.5 %), euphausiids (12.0 %) and oikopleura (17.0 %). Ratio of zooplankton stock to daily consumption was twice higher in the southern part of the eastern Chukchi Sea than in its northern part. The consumption was also higher in the southern area where the index of stomach fullness reached 114.8 ‱ for pollock juveniles and 262.0 ‱ for sand lance juveniles, whereas it was 87 ‱ for juvenile arctic cod and 47 ‱ for juvenile sand lance in the northern area.

Ellochelon vaigiensis (squaretail mullet) adapts to a wide salt spectrum, grows quickly and is easy to raise with other species, so it is the object of attention in aquaculture. Information on the biology and ecology of the species, diet, in particular, is still scattered. Here, we explore the feeding habit, feeding intensity, and food composition of the squaretail mullet. A total of 942 fish (526 males and 416 females) were collected from November 2020 to October 2021 at four coastal sites in the Mekong Delta, Vietnam. The squaretail mullet is an algi‐omnivorous fish, as their relative gut length (1.81) falls into the range 1–3, and the diet is mostly based on algae. The feeding intensity is high due to the high value of the fullness index (4.39 ± 0.08%). The fullness index did not vary by sampling site and month, while RGL and FI changed depending on sex. Bacillariophyta (49.13%), detritus derived from organic matter (30.37%), and Cyanophyta (18.39%) are the dominant food items in the diet composition of E. vaigiensis, in which detritus is the most important food with the highest IRI index. Besides, Euglenophyta (1.00%), Chlorophyta (0.95%), Paramecium (0.06%), Copepoda (0.04%), Rotatoria (0.03%), Polychaeta (0.02%), and Cladocera (0.01%) are also recorded and ranked based on their biovolume. Some differences in diet composition are observed between immature and mature at different seasons and their interactions. Our results increase the knowledge about the feeding ecology of squaretail mullet and can help the sustainable management of this commercially important fish species. [ABSTRACT FROM AUTHOR]

Many traditional economic marine fishery resources have been declining in the coastal waters of China. Amblychaeturichthys hexanema has become one of the dominant species in Haizhou Bay and some other coastal areas of China, playing an important role in marine food webs. We analyzed the feeding strategy of A. hexanema based on the bottom trawl surveys conducted in the Haizhou Bay and adjacent waters in spring and autumn of 2011 and 2013-2016. The feeding habits and main influencing factors of A. hexanema were studied using linear mixed model (LMM). The results showed that A. hexanema fed on 14 prey groups, with Amphipoda, shrimps, Bivalvia and Ophiuroidea as the main prey groups. A total of 37 species were identified in the preys. The dominant prey species were Gammarus sp., Leptochela gracilis, Monoculodes sp., Moerella iridescens and Alpheus distinguendus. Results of the linear mixed model showed that the feeding intensity of A. hexanema in Haizhou Bay was influenced by body length, water depth, survey season, and bottom water salinity. Among them, water depth and bottom salinity had significantly negative effects, whereas the impact of body length was significantly positive. The feeding intensity was significantly higher in spring than that in autumn. Results of cluster analysis showed that A. hexanema had different feeding habits between two length groups as divided by a threshold of 70 mm body length. The change of feeding habit was mainly attributed to the variations in predation ability and food availability. Feeding strategy analysis showed that trophic niche of A. hexanema had large components between phenotypes and low intraspecific competition for prey. This study would contribute to our understanding of life history characteristics and ecological habits of A. hexanema, and provide scientific support for the sustainable utilization and management. [ABSTRACT FROM AUTHOR]

The goal of this study was to determine the temporal and spatial distribution of the gut contents of Squalius cii specimens in a permanently interrupted Karamenderes River. The specimens were sampled at seven distinct locations along the Karamenderes River in summer 2012, autumn 2012, and spring 2013. The gut contents of a total of 157 specimens were examined. The data on the identified food organisms were quantified as the percentage of the index of relative importance (IRI%), niche breadth (BA), trophic level (TL), feeding intensity (Vacuity Index, VI), and food diversity (H'). In all seasons, the examined specimens were found to mostly feed on the members of the Insecta family in the river's upper section and on Bacillariophyceae and macrophytes in the lower section. The feeding intensity was found to be the highest in spring 2013, while the food diversity was realized to exhibit the highest value (2.21) at the Karaköy 1 site in summer 2012. The niche breadth of the examined specimens varied between 0.01 and 0.73, whereas their trophic levels ranged between 2.01 and 3.48. The S. cii specimens were fed on high-quality foods in the upper section of the dam. [ABSTRACT FROM AUTHOR]

Tor malabaricus (Jerdon, 1849) commonly known as Malabar mahseer, is an endangered cyprinid endemic to Western Ghats biodiversity hotspot of India. For a better understanding of their feeding ecology, a study was conducted on 208 specimens collected from Chalakudy River with a total length ranging from 160–530 mm and total body weight of 71–1515 g. Gut content analysis revealed that T. malabaricus is primarily omnivorous, relying on benthic diet, preferably detritus (32.13%) and plant materials (22.96%) mostly throughout the year. However, during the spawning season (July-November), a greater preponderance of insects, crustaceans, molluscs, and nematodes was observed in their diet. The results of gastrosomatic index (GaSI) and feeding intensity indicated that feeding activity of T. malabaricus is considerably reduced during the spawning period. Results not only provide necessary baseline information about the feeding ecology of T. malabaricus in the wild for effectively managing and conserving the species but also provides an insight on its vulnerability for being displaced from its natural habitat due to the pressure from competition for food. [ABSTRACT FROM AUTHOR]

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The purpose of this study was to examine the fatty acid and chemical composition of the Longissimus dorsi (LD) from male Tuj and Hemşin lambs reared in extensive, semi-intensive and intensive feeding systems. At the end of 90 days eight lambs from each breed and feeding system were slaughtered to determine chemical composition, and six lambs in each group were selected at random to assess fatty acid composition. Breed and feeding system interaction affected the quantities of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA), and the atherogenic (AI), thrombogenic (TI), and nutritive value (NVI) indices. In Hemşin the ratio of PUFA to SFA was higher in lambs fed in the extensive system than those produced in the semi-intensive and intensive systems, which were similar, whereas in Tuj this ratio decreased from the extensive to semi-intensive to intensive feeding systems. The ratio of omega n-6 to omega n-3 fatty acids was lower in the extensive and semi-intensive systems than it was in intensively fed Hemşin lambs, but increased with the intensity of feeding in Tuj lambs. Intramuscular fat content was higher in Hemşin lambs than in Tuj lambs and increased with the intensity of the feeding system. Conjugated linoleic acid content (CLA) was affected by feeding system in Hemşin lambs, but not in Tuj lambs. Because of their high PUFA/SFA ratio and low TI value, Tuj lambs reared in extensive feeding system were deemed to have the best performance. [ABSTRACT FROM AUTHOR]

Information on fish feeding habits and trophic levels shed light on trophic profiles and energy transfer within the aquatic ecosystem. In this study, tilapias (Oreochromis niloticus, Sarotherodon galilaeus, and Coptodon zillii) samples from commercial fisheries of Lake Nasser were collected during autumn 2015 and spring 2016, and gut contents were examined. Results showed that plant tissue was more frequent in guts of C. zillii, and sand particles and green algae were more frequent in guts of O. niloticus, while diatoms and sand particles were more frequent in S. galilaeus. Moreover, food of plant and animal origins dominated in large-sized O. niloticus except for hydrophytes that dominated in medium-size samples only. The guts of female O. niloticus contained more plant components than the male. In contrast, the guts of female S. galilaeus contained food of animal origin more than male. Food of plant origin increased in the guts of O. niloticus and S. galilaeus in spring, meanwhile, it increased in the guts of C. zillii in autumn. The trophic level ranged from 2.00 to 2.40 for the three species. The results of this study contribute to the understanding of the feeding habits and trophic levels of these economically important species in Lake Nasser.

The data of field and laboratory studies of feeding, mating behaviour (of 19 pairs observed in the field), reproduction of the solifuge (Camel-spider) Galeodes araneoides, as well as moulting and age-related feeding characteristics of nymphs at different stages of development are presented. Arthropods of 4 classes, 12 orders, 19 families were found in the diet of solifuges under natural conditions. Positive selectivity was noted for some groups of food objects: Isopoda, Araneae, Opiliones, Orthoptera, Hymenoptera. In the laboratory, when feeding solifuges by the most abundant representatives of the fauna of arthropods caught in nature, predators have shown preference for prey of representatives of 3 classes, 8 orders, and 23 families (mainly insects and spiders). The intensity of feeding and the width of its spectrum in nymphs under laboratory conditions increases with their age, reaching their maximum by the onset of the adult stage. [ABSTRACT FROM AUTHOR]

Gypsy moth (Lymantria dispar (L.) is one of most important defoliating pests of deciduous trees. Due to increased environmental demands, the use of plant-based preparations is gaining in importance as a control option for this pest in forestry, agriculture and horticulture. The aim of this study was to evaluate antifeeding and insecticidal activity of 0.5, 1 and 2% extracts of Ailanthus altissima bark and leaves, and Morus alba leaves, against L. dispar larvae under laboratory conditions. Antioxidant capacity of plant extracts was determined, as well as the content of phenolic compounds by spectrophotometric and HPLC-DAD methods. Antifeeding and insecticidal effects were tested in a "no-choice" test. The highest content of all bioactive phenolic compounds was in A. altissima bark and M. alba leaf extracts. The lowest leaf consumption after 24 and 48 h was in A. altissima bark (5.03, 9.30%, respectively) and M. alba leaf (1.44, 3.22%, respectively) extracts. A. altissima bark and M. alba leaf extracts expressed strong antifeeding activity. After 24 h, all extracts expressed slight insecticidal effect (2.25-17.50% of mortality). The mortality increased after 48 h in treatments with A. altissima bark extract, at all applied concentrations (40.0-57.50%) and M. alba leaves at 1 and 2% concentrations (30.0-62.50%). Our results indicate that extracts of A. altissima bark and M. alba leaves may act as effective low-cost natural protectants able to control the presence of gypsy moth in ecosystems. Extracts of A. altissima bark and M. alba leaves expressed strong antifeeding activity and significant insecticidal effect on gypsy moth larvae, at all applied concentrations. [ABSTRACT FROM AUTHOR]

Marine capture of Sphyraena putnamae along western Bay of Bengal has been increasing. Owing to scarcity of information available on feeding dynamics globally, the present study was conducted using 763 individuals captured during 2017–19, to decipher trophic ecology and relationships. Of the individuals analysed, 54.8% had their stomachs either empty or with trace amounts of food, 27.3% had part-full stomachs and 18.0% had full stomachs. Stomach vacuity and fullness as well as predator–prey weight ratio varied with increase in body size, implying higher feeding intensity in large-sized fishes. Feeding activity was highest during July–November and lowest during March–April. The species is an opportunistic piscivorous pelagic predator that feeds on teleosts (>85%) and cephalopods. Sardines were the major prey, followed by whitebait, squid, bigeye scad, Indian scad, silverbellies and Indian mackerel. Diet contents were similar between sexes (82.17%); however, it varied among seasons (56.86–69.85%). Shifts in prey preferences from sardines, squid and bigeye scad to ribbonfish, shad, grunter, Indian mackerel, horse mackerel and Acetes were observed with increase in fish size, and diet varied between individuals sized <60.0 and >60.0 cm. Trophic level value was 3.51 ± 0.13 and Levin's Standardized Niche Breadth Index was 0.21. Dietary niche breadth varied across seasons and sizes, with higher values during summer and winter (0.36–0.41) and in fish measuring >45.0 cm (0.50–0.68), which implies generalized feeding behaviour. The present study represents the first detailed report on the diet of S. putnamae and will provide a substantial contribution to stock management through understanding of trophic interactions. [ABSTRACT FROM AUTHOR]

No prior comprehensive information on the reproductive biology and trophodynamics of Aluterus monoceros was globally available. The present study was performed on 1036 individuals landed along the western Bay of Bengal during 2017 to 2019. Length ranged between 25.3–64.4 cm in females (mean at 48.34 cm) and from 21.5–64.1 cm in males (mean at 47.83 cm). Growth was negatively allometric with no significant difference between sexes. Sex ratio (F:M) was 1.03 with variations based on sizes and months. Size at sexual maturity for females and males was 40.85 and 41.60 cm, respectively. The species spawned throughout the year with major and minor peaks during February to May and October and November. Absolute fecundity increased linearly with length and weight and ranged from 33,640 eggs to 12,39,202 eggs. Stomachs were empty or with trace amounts of food in 59.17%, part-full in 34.07% and full in 6.76% of the fishes. Stomach vacuity and fullness and predator–prey weight ratios varied with an increase in body size, implying higher feeding intensity in large-sized fishes. Feeding activity was more intense during June–August and less during the peak spawning months. The species is omnivorous and a bottom feeder. Teleosts contributed the most to the prey items (43.23% by Index of Preponderance) implying preference for carnivory. Ontogenetic shifts and seasonal variations in prey items were observed. The present study provides paramount information that can significantly contribute to the management and conservation of monacanthid stocks in northern Indian Ocean. [ABSTRACT FROM AUTHOR]

• A method for assessing fish feeding intensity from thumbnail images of feeding splashes is proposed. • Adaptive tuning of receptive fields based on a multi-kernel selection mechanism. • Development of a semi-supervised object detector using CAM pseudo-labels. • Grey-level and grey–gradient co-occurrence matrices used to extract water splash classification features. Assessment of fish feeding intensity provides effective feedback on fish starvation, which is important for improving feed utilisation and reducing water pollution. The vigorous gathering, jumping, or chasing of fish during feeding produces splashes of different sizes. The size of the splash reflects the intensity of fish feeding. However, the diverse splashes, reflected light spots on the surface of the water, and ripples created by fish movement pose inevitable problems for direct quantification methods. These methods require extensive data labelling and complex pre-processing to eliminate disturbances. Hence, this study proposes a method for assessing fish feeding intensity using a workflow involving several deep learning-based techniques such as an adaptive receptive field image feature extraction network based on a multi-kernel selection structure that becomes the teacher module for a semi-supervised splash detection module that uses a class activation map to create pseudo-labels for splashes. Feature extraction is done on the detected feeding splashes using a grey-level co-occurrence matrix and a grey–gradient co-occurrence matrix, which are then used to assess fish feeding intensity using a regression multi-classification model. The experimental results show that the feeding intensity assessment method proposed in this study achieves a mean accuracy of 98.22%, a false detection rate of 1.27%, and a missed detection rate of 2.75%; these results provide practical implications for the design of effective feeding systems that can improve feed utilisation, reduce water pollution, and enhance the welfare of farmed fish. [ABSTRACT FROM AUTHOR]

Supplementary feeding of birds may have considerable ecological and evolutionary effects on bird communities. However, there is a lack of basic information on the prevalence, frequency and quality of supplementary feeders, especially in African urban areas. Here we describe the prevalence, reliability and quality of artificial nectar feeders in suburbs in the Cape Floristic Region, South Africa, where many bird-pollinated plant species occur. Results from 291 questionnaires, completed by garden owners with an interest in birds, reveal that 57% of respondents have feeders in their gardens and 51% refill their feeders multiple times per week. The sugar concentration, total duration of feeding and frequency of feeding did not affect abundances or species richness of nectarivorous birds in gardens. We found a higher incidence of breeding sunbirds and sugarbirds in gardens with feeders than gardens without. Supplementary nectar feeding in this area has the potential to contribute to conserving nectarivorous birds, but investigation into the possible negative effects is needed. [ABSTRACT FROM AUTHOR]

Bats have important ecological roles in ecosystems, but many species are threatened because of anthropogenic impacts. Tanzania has limited information on how bats respond to habitat modification. This makes it difficult to anticipate which bat species are at risk. Bat activity and species richness were assessed in five land‐use types: forest and banana–coffee (upland habitats), rice paddy, riverine and sisal estate (lowland habitats). Mist nets, harp traps and bat detectors were used to sample bats. Species richness differed between habitats. Bat activity levels were higher in lowland habitats than upland habitats. Riverine and rice paddy habitats were shown to have an important role as foraging sites for many insectivorous bats as bat species richness and activity were generally higher than other habitats. Fruit‐eating bats preferred riverine and banana–coffee habitats. We recommend using organic manure as alternatives to chemical fertilisers, and pesticide use should be avoided in rice paddies. Riparian vegetation along rivers and water bodies should be maintained as important faunal nesting, roosting and/or foraging grounds. The requirement that farming practices be at least 60 m from the river should be strictly enforced. These recommendations will help in the conservation of bats and their habitats in modified agricultural landscapes. [ABSTRACT FROM AUTHOR]

Coryphaena hippurus is a large pelagic species and constitutes an important by-catch in drift gillnet, trolling and long-line fishing gears operated along the Bay of Bengal, northeastern Indian Ocean. The present study, first from the region, is aimed at deciphering the feeding dynamics from 1150 individuals collected from 2017 to 2019. 32.17% of the fishes had empty stomachs or was with food traces, 45.57% had partially-full stomachs and 22.26% had full stomachs. The feeding intensity was inferred through stomach filling and predator-prey weight ratio, which was higher in May and lower in January, and increasing as increase in the fish size. Coryphaena hippurus is considered a piscivorous pelagic predator as pelagic teleosts contribute more than half of the prey species. Major prey species were big-eye scad (27.3%), squid (10.3%), crabs (9.3%), Indian mackerel (7.2%), Indian scad (5.9%), whitebaits (5.7%) and sardines (5.4%). Scads and crabs were abundantly preyed during summer and winter, while clupeids and engraulids in monsoon; however, no significant variations were observed in prey composition between sizes. Trophic Level was 4.22 ± 0.15 and Levins Standardized Niche Breadth Index was 0.30. Dietary niche breadth was higher during summer (0.48) and monsoon (0.33) and in fishes measuring 60.0–74.9 cm (0.51) and below 45.0 cm (0.48) indicating generalised feeding. This primary study from Bay of Bengal is the first comprehensive report on trophodynamics for the species and would contribute to its management using trophic interactions. [ABSTRACT FROM AUTHOR]

Bohai Bay, a representative semi‐enclosed bay of China, has been severely impacted in recent decades by rapid human development. Although the mantis shrimp Oratosquilla oratoria plays an important role in the Bohai Bay ecosystem and fishery, its feeding ecology and the impact of habitat changes on its feeding habits are poorly known. In this study, we sought to identify its feeding strategy through the separation of stomach contents, and to describe its trophic ecology during maturation in the Tianjin coastal zone of Bohai Bay by the DNA barcoding method using a fragment (about 690 bp) of the mitochondrial cytochrome oxidase I (CO I) gene. A total of 594 specimens were collected from March to July 2018, and 347 (58.42%) stomachs were found to have food remains. More than half of the O. oratoria individuals had poor feeding activity, and the degree of feeding of females was higher than that of males, but there was no significant difference in the visual fullness index and the fullness weight index (FWI) between sexes for each month. In addition, the feeding activity of O. oratoria was consistent across the months, suggesting in artificial breeding programs it is not worried too much about the accessional diet supplied to the female bloodstocks except maintaining their normal food. A total of 167 retrieved prey items yielded 187 readable sequences; 86.63% of these sequences could be assigned to the species level. Consequently, 25 different prey taxa covering all readable sequences were identified, showing O. oratoria is a generalist predator. In terms of percent composition by frequency of occurrences (%N), crustaceans and fishes accounted for the same and highest percentage (35.83%) in the mantis shrimp diet, followed by mollusks (24.59%) and the remaining marine organisms (3.73%) including Polychaeta (2.67%), Sagittoidea (0.53%), and Chromadorea (0.53%). The result shows the benthic fish Oxudercidae (family) appears to be an especially important food supply for O. oratoria during maturation. The degree of cannibalism decreased with an increase in diet species and the frequencies of cannibalism in this study was noticeably higher than that in previous studies, suggesting that cannibalism may be a significant feeding strategy in the mantis shrimp O. oratoria in the Tianjin coastal zone of Bohai Bay, and because of the frequently cannibalistic behavior, the high stocking density of broodstocks should be avoided. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the haematological profile of rainbow trout after applying of different intensities of feeding (FL1-2.5% BW day-1, FL2-3% BW day-1, FL3-3.5% BW day-1, FL4-4 % BW day-1, FL5-4.5 % BW day-1 and, ad libitum-FL6). Fish were reared in a recirculating aquaculture system (RAS), provided with twelve rearing units (in duplicate) for 44 days. Blood samples were collected from twelve fish on each experimental variant, and were made before and after the experimental trial. Red blood cell counts (RBCc), haematocrit values (Hct), haemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), total serum glucose (Glu) and total proteins (TP) were determined. Also, in order to determine the leukogram and the absolute number of leukocytes, blood samples were collected and used immediately to make smears. At the end of the experiment, ANOVA test revealed no significant changes (p>0.05) in the RBCc, Hct, Hb, MCV, MCH, MCHC and glucose concentration (Glu), while the total proteins (TP) from blood serum increased significantly (p<0.05) with the increasing of the feeding intensity, except for ad libitum feeding, were total serum protein decreased. Regarding the total number of leukocytes, in general, it has not been registered statistically significant changes (p>0.05). Lymphocytes (relative and absolute) have remained relatively constant, without significant variation (p>0.05). The main conclusion that emerges from this current study shows that in the case of rainbow trout reared under recirculating aquaculture system conditions, feeding intensity does not significantly influence the haematological profile. [ABSTRACT FROM AUTHOR]

The bulk of marine fish production in Morocco comprises small pelagic with a large predominance of the European sardine Sardina pilchardus. Information on feeding intensity and diet composition of small pelagic fish are of great importance for understanding species ecology and life-history traits and fisheries management. In the present study, we compared body condition, sexual maturation, feeding intensity and diet composition (stomach content analysis) in sardines from contrasting fishing environments representative of the three Moroccan Atlantic stocks (North: Larache; central: Safi; and south: Dakhla) in spring 2016. The body condition factor increased from north to south and varied inversely with gonado- and hepato-somatic ratios. The feeding intensity was low in Larache and Dakhla and higher in Safi, related to the reproductive status. Sardines are generalist feeders selecting primarily zooplankton (copepods and cnidarians) in Larache and phytoplankton (diatoms and dinoflagellates) in Dakhla and Safi. However, based on carbon content, sardines from the three locations are rather zooplanktivorous. Great similarity in numerical specific abundance was found between the diets in sardines from Dakhla and Safi, which are areas of high phytoplankton productivity in the spring. In contrast, there was a low similarity in diet between sardines from Dakhla and Larache in relation to the low productivity and differences in sexual maturation of sardines from the latter. We concluded that in spring, the feeding intensity and diet composition of sardines depend on their reproductive status and ecosystem productivity, which affect their body condition. [ABSTRACT FROM AUTHOR]

Information on fish feeding habits and trophic levels shed light on trophic profiles and energy transfer within the aquatic ecosystem. In this study, tilapias (Oreochromis niloticus , Sarotherodon galilaeus, and Coptodon zillii) samples from commercial fisheries of Lake Nasser were collected during autumn 2015 and spring 2016, and gut contents were examined. Results showed that plant tissue was more frequent in guts of C. zillii , and sand particles and green algae were more frequent in guts of O. niloticus , while diatoms and sand particles were more frequent in S. galilaeus. Moreover, food of plant and animal origins dominated in large-sized O. niloticus except for hydrophytes that dominated in medium-size samples only. The guts of female O. niloticus contained more plant components than the male. In contrast, the guts of female S. galilaeus contained food of animal origin more than male. Food of plant origin increased in the guts of O. niloticus and S. galilaeus in spring, meanwhile, it increased in the guts of C. zillii in autumn. The trophic level ranged from 2.00 to 2.40 for the three species. The results of this study contribute to the understanding of the feeding habits and trophic levels of these economically important species in Lake Nasser. [ABSTRACT FROM AUTHOR]

Cephalopods are exclusively marine molluscs and there are about 600 species in the world oceans and of these less than a hundred species are of commercial importance. Indian squid (Uroteuthis duvauceli) is the commercially important species of Veraval. The marine fish landing during the year 2013 of the country has been estimated as 3.78 million tonnes. Marine squid landings in India during the year 2013 was 100014 tonnes (CMFRI, 2013). The present study gives a brief information about the feeding biology of squids. Gujarat is one of the most important maritime state of the nation contributing to the nation's economy. Cephalopods including squids are one of the most important export commodity from the state. The length-weight relationship study would help to analyse the status of squid fishery off Gujarat mainland and the study about the feeding biology using monthly stomach content data of squid will help to know about the feeding intensity in different seasons and their diet composition. The maximum Dorso--Mantle length encountered during the study was 205 mm, where as the minimum was 56 mm. The food of U. duvaucelli appears to consist of fish, crustaceans and cephalopods. The detailed results of studies on feeding biological aspects such as length composition, length-weight relationship, feeding intensity are presented here in this paper. [ABSTRACT FROM AUTHOR]

Feeding of fish juveniles in the eastern Bering Sea is investigated for the periods of 2003-2006 considered as relatively «warm» and 2007-2012 considered as relatively «cold». Small- and medium-sized zooplankton was the dominant prey in the 2003-2006, in particular copepods prevailed in the food of walleye pollock (41.5 %), pacific herring (48.3 %), and sand lance (71.7 %) juveniles, which in turn were the prey for pollock, herring and cod yearlings and other predators. On the contrary, large-sized zooplankton was more abundant in the 2007-2012, so arrowwarms ( Sagitta sp.), large-sized copepods (in particular Calanus marshallae ), euphausiids (mainly Thysanoessa raschii ), hyperiids, and pteropods were the prey for young fish: C. marshallae - for juveniles of pollock (40-45 % by weight) and capelin (32-34 %), Th. raschii - for yearlings of pollock (51 %) and herring (36-46 %), cold-water hyperiid T. libellula - for adult pollock (24 %), juvenile cod (9-18 %) and juvenile herring (9-11 %), whereas portion of fish in the diets was insignificant. In the warm period (2003-2006), juvenile pollock, herring, sand lance and capelin were zooplankton-eaters with the diets similarity 67 %, while yearlings of pollock and juveniles of cod, herring, sandfish, and atka mackerel were fish-eaters preying upon pollock juveniles. In the cold period (2007-2012), the diets of juvenile pollock, juvenile and adult capelin, and juvenile sand lance were also similar at 85-70 % but they preferred large-sized copepods and euphausiids ( C. marshallae and Th. raschii ), while yearlings of pollock, yearlings and adults of herring, and juveniles of sand fish and cod had the diets of 70 % similarity with Th. raschii prevalence. Feeding intensity was high for all species: the mean stomach fullness was 150-200 ‱ for pollock juveniles and yearlings, 200-250 ‱ for cod juveniles, 200-258 ‱ for sand lance juveniles, 302 ‱ for herring juveniles, and 178-250 ‱ for juvenile atka mackerel. The fullness had diurnal rhythm with three peaks: at noon - up to 179 ‱, in evening - up to 213 ‱, and at night - up to 204 ‱ (the data for walleye pollock juveniles in «cold» years only). Daily food ration of juvenile pollock is estimated as 6.7 % of its body weight in the «warm» years and 7.0 % in the «cold» years.

Change in prey for pacific salmons in the eastern Bering Sea is considered between the periods of relatively warm (2003-2006) and relatively cold (2007-2012) conditions on the base of data obtained in the frames of BASIS research program. In the warm period, mean biomass of the large-sized, medium-sized and small-sized fractions of zooplankton was 287.9, 258.2, and 109.2 mg/m3, respectively. In these conditions, fish prey was the basis of diet for pink salmon (70-68 % of ration), chum salmon (64-84 %) and sockeye salmon (45-87 %). Pink, chum, sockeye, and coho salmons had similar diet with the dominance of juvenile walleye pollock (similarity 70-90 %), in contrast to the diet of chinook salmon (40-70 % similarity with others). In the cold period, the large-sized zooplankton was much more abundant (1094.8 mg/m3 on average) mostly due to higher abundance of Copepoda and Chaetognatha; euphausiids, hyperiids, and pteropods were more abundant, as well. In these conditions, zooplankton, mainly euphausiids Thysanoessa raschii and hyperiids Themisto libellula and T. pacifica , dominated in the diet of plankton-eating salmons: 86-92 % of the ration for pink salmon, 88-92 % for chum salmon, and 74-81 % for sockeye salmon; all these species and chinook juveniles had similar diet (70-80 % similarity). On the contrary, predatory salmons as coho and chinook adults still preyed on fish. Mean daily rations in the warm/cold periods are estimated as 12.1/9.4 % of body weight for sockeye salmon with the length 10-20 cm, 8.6/7.3 % for sockeye salmon 20-30 cm, 8.3/13.8 % for chum salmon 10-20 cm, 8.6/10.0 % for chum salmon 20-30 cm, and 8.8/10.3 % for pink salmon 10-25 cm. The prevalence of nekton or planktonic food does not affect on daily rhythm of feeding intensity: juvenile salmons feed mainly in the daytime, so they have the maximal index of stomachs fullness in the evening or early night (100-230 ‱, both in the warm and cold periods). Generally, the salmons prefer fish larvae and juveniles in conditions of low zooplankton abundance and large-sized zooplankton in conditions of its high abundance. Selectivity on euphausiids, hyperiids and pteropods is observed only in conditions of high zooplankton abundance and is an indicator of sufficient food supply.

Fresh water mud eel (Monopterus cuchia) is considered as a highly nutritious food fish having therapeutic value. Therefore, a study has been conducted to acquire information on the food and feeding habit of this species in relation to reproductive cycle. Relative Length of the Gut (RLG), Gastro-Somatic Index (GaSI) and Analysis of gut content have been studied. It was observed that insect larvae and zooplankton comprised the major part of Gut content. GaSI values of 2.70 (Spent), 3.14 (Pre-Breeding), 2.13 (Breeding) and 2.56 (Post-Breeding) was observed to be different from all the four stages. Moreover, GaSI value was lowest during breeding period and highest during pre-breeding period. Lowest GaSI value of 2.13 indicates period of low feeding intensity which coincides with breeding period. Based on the obtained results, Monopterus cuchia was considered as a carnivorous fish since the RLG value is less than 1. [ABSTRACT FROM AUTHOR]

This study investigates the feeding intensity and the morphology of the feeding apparatus (gill rakers) of the European sardine Sardina pilchardus (Walbaum, 1792) in two hydro-dynamical contrasting areas of the eastern boundary upwelling system off Morocco. North, one area is characterized by a summer upwelling while South, the other area is more productive with a strong and almost permanent upwelling. Fish from both areas differ in their feeding intensity, fish condition and gill raker number but no difference is found in the length of the first lower branchial arch. Fish from the southern fishing area are characterized by higher gill raker number and higher feeding intensity mainly from January to May, while specimens from the other area have a significantly lower gill raker number and higher feeding activity from July to November. The high values of fullness index during summer-autumn and the lower value of gill raker number suppose that S. pilchardus from the latter area feed more intensively on larger preys, taking advantage from the trophic conditions prevailing during these seasons. In the southern area, S. pilchardus develop more many gill rakers which might allow to filter the smaller and more abundant preys. These results show that seasonal differences in environment conditions, i.e. permanent versus seasonal upwelling that induce differences in the available resources, may have shaped differently the feeding apparatus, the feeding activity and the condition of S. pilchardus. [ABSTRACT FROM AUTHOR]

Accurately and objectively analyzing fish feeding intensity is essential to guiding feeding and production techniques. Fish feeding intensity in recirculating aquaculture systems (RAS) can be used to indicate a fish's appetite. However, the low efficiency and lack of objectivity of manual observation are problems with current fish feeding intensity assessment processes. Applying acoustic techniques to aquaculture issues is an insufficiently explored area that requires new investigations, particularly into methods that explore temporal information in acoustic spectrograms. With Oplegnathus punctatus as the experimental species, we proposed a fish feeding intensity detection method based on the Mel Spectrogram and MobileNetV3-SBSC lightweight networks. First, the Oplegnathus punctatu s feeding sound dataset, which has a total of 3 types—"strong," "medium," and "none," was built. Next, Mel Spectrogram feature maps were extracted using steps including preprocessing, Fast Fourier Transform (FFT), Mel filter bank (MFB), etc. Finally, the MobileNetV3-SBSC lightweight network was used to detect and recognize the obtained feature maps. Experimental results indicated that the proposed MobileNetV3-SBSC model, as compared to the MobileNetV3-S model, improved test accuracy by 4.6% and decreased test loss by 67.4% with only a 0.84% increase in the number of parameters and a 3.08% increase in the model size. Additionally, we have verified that the accuracy of the test set was 59.6%, 53.3%, 83.3%, 85.3%, and 85.9% for groups of 5, 15, 40, 70, and 100 fish, respectively. This study demonstrated that the proposed method is not applicable to a small number of fish, which means that when the numbers of fish are small, changes in the feeding of individual fish would have a significant effect on the whole feeding feature map, leading to negligible changes in feeding features. However, in view of the commonly high aquaculture density, the proposed method can be used to automatically and objectively examine fish feeding, which could provide a theoretical basis and methodological support for further feeding decisions. [ABSTRACT FROM AUTHOR]

Big-scale sand smelt is one of the fishes with high ecological value, which consume by fishes such as sturgeon in the Caspian Sea. In this study, 191 samples of Big-scale sand smelt from southeast coast of the Caspian Sea were collected seasonally from December 2013 to September 2014. In the present study, food items and the relative index of gastrointestinal (RLG), stomach emptiness index (VI) and feeding intensity (IF) were determined. The fork length, weight and age (mean ±SD) were 7.70 ± 1.09 cm, 3.64 ± 1.49 g and 2.00 ± 0.81 year, respectively. This fish with a relative gastrointestinal tract length of 0.46 ± 0.06 (mean ± Standard Deviation) can be considered as a carnivorous fish. The average of empty stomach was 45% showing big-scale sand smelt is a relatively voracious feeder. The average intensity of feeding (mean± Standard Deviation) 535±221.21, as a moderate level for this fish in the region. Gammarus (benthos) and Daphnia (zooplankton) were the favored food for this fish. This study also showed opportunistic hunting activities of this fish.

Specimens of E. thoracata were collected twice in a month during the period of February 2015 to January 2016 from Burondi, landing centre of Ratnagiri coastfor investigated food and feeding habits.E. thoracata is a planktivorous fish, mainly feeding on copepods, cladocerans, crustacean's larvae, fish eggs, bivalve larvae, tintinnids and diatoms (Ceratium spp., Coscinodiscus spp., Nitzschia spp., Rhizosolenia spp.). Among the food items copepods were most dominant (69.09%) item in the diet followed by crustacean appendages (7.41%) and lowest item was Rhizosolenia spp.(0.01%). Group-wise index of preponderance of different food items indicated that crustaceans formed most dominant group (83.81%). Monthly index of preponderance of different food items indicated that copepods were dominant in all the months. Sex-wise index of preponderance indicated that copepods were dominant for both the sexes recording 71.88% in males and 65.06% in females. In pooled data for feeding intensity full stomach was observed in 16% fish during May, 3/4th full stomach was observed in 26% fish during month of September, 1/2thfull stomach was observed in 40% fish during month of April, 1/4th fullstomachfeeding was observed in 58% fish during the month of December whereas empty stomach was observed in 24% fish during February. Highest percentage of full stomach was observed in 23.08% in male during June and 21.74% in female during May, whereas empty stomach was observed highest in February for both the sexes. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate the food and feeding habits of cobia, Rachycentron canadum from the northeastern waters of Peninsular Malaysia. Stomach content of 82 R. canadum fish were analyzed with reference to gender and size classes. Fish was the most dominant diet component for R. canadum with % IRI value of 95.3%, followed by squid (3.1%), crab (1.5%), and shrimp (0.07%). Fish was also predominant regardless of gender and size classes of the R. canadum in the study area. Shrimp was not taken by the male, but found in females with sizes ranged between 80 and 120 cm TL. Rachycentron canadum that was larger than 120 cm TL also did not prefer crab as part of its diet component. Their feeding intensity increased with size accordingly that was indicated by the increase in the percentage of active feeder. This research finding will contribute to the development of R. canadum culture in Malaysia. [ABSTRACT FROM AUTHOR]

The purpose of this experiment was to evaluate how feeding intensity influence the growth performance of juvenile rainbow trout (Oncorhynchus mykiss) reared in a recirculating system. A number of 152 rainbow trout with an average weight of 174.41±0.73 g were divided into four rearing units in order to create the same stocking density (20 kg/m3). The fish were fed a 41% protein feed. Two variants were compared V1 (B1, B2) and V2 (B3, B4), with repetition. In V1- 1.0% feed from total biomass and a double amount of feed in V2-2.0% from total biomass. At the end of the experiment were obtained average body mass of 224.09±0.20 g in variant V1 and 245.59±0.73 g in variant V2. Specific growth rate (SGR) varied as follows: V1-0.95 g% / day, V2- 1.33 g% / day. Regarding the feed conversion factor (FCR), the better values were obtained in V1 variant -0,93 g feed/g gain biomass, while in V2 we obtain a value of FCR-1.22g feed/g gain biomass. The parameters of fish growing showed that changing the quantity of fodder, the fish growing was positively influenced. [ABSTRACT FROM AUTHOR]

A total of thirty-four Czech Fleckvieh (CF), Charolais (CH) and Charolais × Czech Fleckvieh (CH × CF) bulls with an average weight of 284 kg were included in the experiment and fed ad libitum two mixed diets: MS (based on maize silage) and LCS (based on legume-cereal and lucerne silages) with different concentrations of dietary energy until slaughter at the target live weight of 600 kg. The CF bulls consumed more dry matter (DM) of feed daily than the CH bulls (P < 0.05) and gained weight less efficiently than the CH × CF and CH animals (P < 0.01) during the entire experiment. The killing-out percentage was lower in the CF than in the CH × CF and CH (P < 0.05). The CH bulls received a higher score for carcass conformation and a lower score for carcass fatness (P < 0.01) than the CF bulls, had lower proportions of kidney and cod fat (P < 0.01) than the CH × CF and CF bulls, and produced the highest percentage of high-priced meat (P < 0.05) and the lowest percentage of separable fat (P < 0.001). The bulls on the MS diet were younger than the others at the end of the experiment (P < 0.01), gained weight more rapidly (P < 0.001), consumed less DM (P < 0.001) daily, utilized nutrients more efficiently over the entire experimental period (P < 0.001), and had a higher proportion of internal fat than the LCS bulls. It can be concluded that purebred CH bulls were superior to the other breed groups in most of the traits observed. The intensive diet based on maize silage increased average daily gains, reduced the time needed to achieve the target slaughter weight, and improved the feed efficiency of bulls.

Long-term density-dependent changes in the population dynamics of the king weakfish Macrodon atricauda of southern Brazil between 1976 and 2013 may be related to a change in diet and an increase in feeding intensity. The importance of the small crustacean, Artemesia longinaris, increased in the diet of adults, whereas the importance of teleosts decreased and the frequency of full stomachs increased. Macrodon atricauda currently benefits from a high availability of A. longinaris, which results in a higher energy intake per individual, which, in turn, induces faster body growth and an earlier onset of sexual maturation. [ABSTRACT FROM AUTHOR]

A total of 1469 fishes of 39 species were caught between July 2010 and March 2011, using coastal seine net from three stations in Shatt Al-Arab River (Al-Daeir, Hamdan and Al-Fao). Environmental factors in the river were measured (water temperature (21.85'4.71.C), pH (7.96'0.25), salinity (3.26'2.25 ppt), D.O.(9.15 '1.77 mg/L) transparency (37.29'16.08cm).The dominant species in Shatt Al-Arab River was Carassius auratus which comprises 20.76% and 42.90% from total numbers and weight, respectively. The feeding intensity (8.79 - 12.37 point/fish) for all fed fishes indicates that most fishes fed with half fullness stomach at all seasons. The food contents of 593 individuals belonging to 15 species were analyzed for reliable results. Sixteen food items used to calculate standardized diet compositions and trophic levels of fishes. Plant origin food items comprise 48.54% of preponderance index, while it was 39.43 and 12.03 % for animal and organic matter food items, respectively. Shatt Al-Arab feeding index showed two peaks at spring and autumn (61.87, 59.74, respectively).While the mean value of trophic level for vegetarian fish species was 2.06 which differ significantly (F=12.14,145.01 P= 0.013,0.00) from both species which depend on detritus (1.36 ) and on animal (3.38) food items, respectively, which were also significantly different (F=350.04,P=0.00) from each other. [ABSTRACT FROM AUTHOR]