scholarly journals Reproduction and feeding habits of the River Catfish Eutropiichthys vacha (Hamilton, 1822) (Siluriformes, Schilbidae) in an impacted habitat: Kotri hydrodam, River Indus, Pakistan

Our Nature ◽  
2013 ◽  
Vol 10 (1) ◽  
pp. 269-280 ◽  
Author(s):  
Anila Naz Soomro ◽  
Wazir Ali Baloch ◽  
Sayed Iftikhar Hussain Jafri ◽  
Ghulam Hussain Burdi ◽  
Bernerd Fulanda
Keyword(s):  
Feeding Habits ◽  
Gonadal Development ◽  
Temporal Variations ◽  
Cold Season ◽  
Male Dominance ◽  
Minimum Size ◽  
Gut Contents ◽  
Feeding Intensity ◽  
Dietary Shift ◽  
River Indus

Reproduction and feeding habits of Eutropiichthys vacha were studied in Kotri hydrodam, a man-made and human impacted stretch of the Indus River, Pakistan during 2005-2006. A total 303 specimens were sampled and analyzed for maturity stages and gonadal development and food and feeding habits assessed from gut contents. Results showed male dominance over females: sex ratio 1.16:1.0. Minimum size at sexual maturity was 13.9 cm total length (TL). Mean fecundity ranged 1.38x104 to 2.17 x 105. Gonado-somatic index (GSI) was 0.1-2.5 and 0.3-6.5 for males and females, respectively. Highest GSIs were recorded in April. We observe an ontogenic dietary shift in E. vacha: young are omnivorous with insects dominating diet while adults are omni-piscivores with Puntius ticto accounting for 35.4% of species. Other species were Colisa spp., juveniles of Channa spp. and some cyprinids. Feeding intensities were lowest in April at peak of spawning. The intensities increase rapidly after spawning indicating voracious feeding in E. vacha. Feeding intensities in adults are low during the cold season. These results provide for assessment of spatial-temporal variations in feeding intensity in E. vacha while GaSI and diet composition reveal information on environmental shifts and ecosystem fluctuations in the impacted habitats of the River Indus for sound fisheries management.DOI: http://dx.doi.org/10.3126/on.v10i1.7795

scholarly journals Food and feeding habits of the clupeid, Gonialosa manmina (Ham.) from the Kaptai Lake, Bangladesh

2013 ◽  
pp. 53-61
Author(s):  
MA Azadi ◽  
M Nasiruddin ◽  
ASMS Rahman
Keyword(s):  
Feeding Habits ◽  
Gut Contents ◽  
Fish Length ◽  
Feeding Intensity ◽  
Total Length ◽  
Intestine Length ◽  
Food And Feeding ◽  
Total Fish ◽  
Post Spawning ◽  
Gut Length

Food and feeding habits of Gonialosa manmina were done by the analysis of 197 guts of the fish using both occurrence and point methods and also by the Index of preponderance. As per Index of preponderance, the preferred food items were graded as cladocerans (65.34%-1st), copepods (20.96%-2nd), miscellaneous (8.89%-3rd), rotifers (2.81% 4th) and bacillariophyceae (0.77% 5th). High feeding intensity was observed during pre and post spawning months. Significant (P<0.01) positive relationships were observed between the total length (TL) and total gut length (TGL) (TGL=2.09799TL0.89677, r=0.963, t=10.22), total length (TL) and stomach length (StL)(StL=0.18447TL0.7599, r=0.997, t= 39.92), and total length (TL) and intestine length (IL) (IL=0.99105TL1.0256, r=0.9854, t=16.37). Total fish length was slightly shorter than the gut length (1:1.31) and more than 91% animal nature gut contents confirmed that the fish was mainly a surface feeder zooplanktivore in Kaptai lake. DOI: http://dx.doi.org/10.3329/cujbs.v4i1.13386 The Chittagong Univ. J. B. Sci.,Vol. 4(1&2):53-61, 2009

Feeding habits of John Dory, Zeus faber, off the Portuguese continental coast

1999 ◽  
Vol 79 (2) ◽  
pp. 333-340 ◽  
Author(s):  
Alexandra Silva
Keyword(s):  
Prey Species ◽  
Feeding Habits ◽  
Parallel Evolution ◽  
Stomach Contents ◽  
Abundant Species ◽  
Temporal Variations ◽  
Food Composition ◽  
Diet Shift ◽  
Feeding Intensity ◽  
Zeus Faber

The feeding habits of John Dory (Zeus faber) were studied, based on the analysis of stomach contents from fish sampled in five groundfish surveys. These surveys were carried out off the Portuguese coast during different seasons between 1990 and 1992. The main aspects of feeding biology analysed in this paper are: ontogenetic diet changes, temporal variations in food composition and feeding intensity. Multivariate methods were used to investigate ontogenetic diet shifts. Two main length groups were identified: 8.0–24.9 cm fish, feeding mainly on dragonets and silvery pout, and 25.0–55.9 cm fish whose diet was mainly composed of blue whiting and snipefish. A transitional phase (24.0–30.9 cm fish) with a mixed food composition was observed. This ontogenetic diet shift does not seem to correspond to any important change in body morphology but it does coincide with the onset of sexual maturity in the species.John Dory switched from a diet of small prey species with more pronounced benthic behaviour to a diet of larger schooling pelagic species. This suggests parallel evolution to more pelagic foraging behaviour. However, John Dory feeding habits appear to be largely controlled by the availability and accessibility of prey species: (i) the diet of adult John Dory is dominated by very abundant species; (ii) shifts in the main prey items between different times of the year and between different areas seem to be related both with their absolute and relative abundance in the environment and with the overlap between the depth distribution of predator and prey.

scholarly journals Morphology, Food and Feeding Habit of Goby Fish, Parachaeturichthys ocellatus from the Creeks of Mumbai

2020 ◽  
Vol 3 (11) ◽  
pp. 95-100
Author(s):  
Bindu Panicker
Keyword(s):  
Feeding Habits ◽  
Predatory Fish ◽  
Gut Contents ◽  
Fishing Community ◽  
Feeding Intensity ◽  
Fish Samples ◽  
Food And Feeding ◽  
Gut Length ◽  
General Diet ◽  
Food Consumed

Goby fish Parachaeturichthys ocellatus, native to the creeks of Mumbai coast forms a major part of creek fishery for the fishing community inhabiting areas near the creeks. The food and feeding habits of the fish were studied by collecting fish samples every month in from June 2010 to September 2011 from the creeks of Mumbai. The length of the fishes studied ranged between 66mm to 185mm.The body morphology of fish revealed it to be carnivorous benthic and predatory fish. The gut contents of the fish showed the presence of crustaceans as basic food, mollusc and pisces formed the secondary food while detritus formed obligatory food and planktons and other miscellaneous food (larvae of insects, worms, rotiferons, dinoflegellates foraminiferons etc.) were incidental food. An analysis of seasonal variation in food preference and feeding intensity reveal that the male and female P.ocellatus had the same preference throughout the seasons but was different for the juveniles. In P.ocellatus cannibalism was observed, but its occurrence was not regular in the general diet. The relative gut length was 0.68 in male, 0.70 in female and 0.79 in juvenile. The empty guts of P.ocellatus seem to indicate predatory mode of feeding. P.ocellatus occupy the position of secondary and tertiary consumers in the food chain determined by the size and type of the food consumed by the fish.

scholarly journals Food and Feeding Habits of the Deep-Water Mud Shrimp (Solenocera melantho) of Visakhapatnam Coast, India

2017 ◽  
Vol 9 (2) ◽  
pp. 161-168
Author(s):  
Rama Chandra Ganesh PATURI ◽  
Sarvabhowma Chakravarty MYLA
Keyword(s):  
Feeding Habits ◽  
Gut Contents ◽  
Scavenging Activity ◽  
Feeding Intensity ◽  
Diet Preference ◽  
Food And Feeding ◽  
Fish Remains ◽  
Males And Females ◽  
Visakhapatnam Coast ◽  
Food Consumed

The food and feeding habits of the shrimp Solenocera melantho off Visakhapatnam coast were studied qualitatively and quantitatively. Feeding intensity differs in relation to gender, size, season and stage of maturity. Detritus was the major component of the food consumed, followed by crustaceans, molluscs, foraminiferans, fish remains, eggs; sand was also found as one of the gut contents. Diet preference in males and females was similar, but varied with size and season. The index of preponderance of detritus was 50.88% in males and 47.16% in females. Variation in feeding intensity was noticed in relation to size, months and season. The overall feeding intensity in males and females was categorized as actively fed (21.52% and 40.78% respectively), moderately fed (22.07%, 19.72%) and poorly fed (14.07%, 27.03%) respectively. S. melantho may designate as an omnivorous detritivore with scavenging activity. 

Feeding ecology of Symbolophorus californiensis larvae (Teleostei: Myctophidae) in the southern transition region of the western North Pacific

2009 ◽  
Vol 90 (6) ◽  
pp. 1249-1256 ◽  
Author(s):  
Chiyuki Sassa
Keyword(s):  
Transition Region ◽  
North Pacific ◽  
Western North Pacific ◽  
Developmental Stages ◽  
Feeding Habits ◽  
Larval Growth ◽  
Trophic Niche ◽  
Size Class ◽  
Gut Contents ◽  
Wide Range

The feeding habits of myctophid larvae of Symbolophorus californiensis were examined in the southern transition region of the western North Pacific where the main spawning and nursery grounds of S. californiensis are formed. This species is a key component of the pelagic ecosystems of this region, and their larvae attain one of the largest sizes among myctophids. To analyse gut contents larvae, including most life history stages after yolk-sac absorption (3.7 to 22.2 mm body length (BL)), were collected in the upper 100 m layer in 1997 and 1998. Feeding incidence was higher during the day than at night (53.1–92.3% versus 0–5.6%), and daytime feeding incidence increased gradually with larval growth. Larvae fed mainly on copepods of various developmental stages. Larvae of S. californiensis showed an ontogenetic change in their diet: larvae ≤7.9 mm BL (i.e. preflexion stage) fed mainly on copepod eggs and nauplii, while the larvae ≥8 mm BL consumed mainly calanoid copepodites such as Pseudocalanus and Paracalanus spp. In the largest size-class (16–22.2 mm BL), the furcilia stage of euphausiids was also an important prey item. There was an increase in the average prey size with growth in larvae ≤11.9 mm BL, while the number of prey eaten positively correlated with growth in larvae ≥12 mm BL. The trophic niche breadth also increased with larval growth, which would ensure a wide range of available food resources for the larger size-class larvae.

scholarly journals Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

2016 ◽  
Vol 14 (3) ◽  
Author(s):  
Santiago A. Barbini ◽  
Luis O. Lucifora
Keyword(s):  
Body Size ◽  
Diet Composition ◽  
Prey Size ◽  
Prey Availability ◽  
Feeding Habits ◽  
Warm Season ◽  
Cold Season ◽  
The North ◽  
Multiple Hypothesis ◽  
Modelling Approach

ABSTRACT The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS) and crabs in the north region (38º - 41ºS). Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.

scholarly journals Hábitos alimentarios de quironómidos (Diptera: Chironomidae) en lagos del páramo de Chingaza, Colombia

2017 ◽  
Vol 66 (1) ◽  
pp. 136 ◽  
Author(s):  
Yulibey Caleño Ruiz ◽  
Carlos Alberto Rivera Rondon ◽  
Hernando Ovalle
Keyword(s):  
Dietary Habits ◽  
Feeding Habits ◽  
Diet Overlap ◽  
Gut Contents ◽  
High Mountain ◽  
Trophic Guilds ◽  
Use Of Resources ◽  
Fine Particulate ◽  
Chironomidae Larvae ◽  
Well Differentiated

Tropical high mountain lakes show unique environmental conditions where chironomids play an important role in ecosystem functioning. The characteristics of these environments could favor diet overlap and therefore a high interspecific competition. This study described the dietary habits of chironomid genera, identified whether the dietary habits were specialized or generalist, and analyzed the diet overlap in the genera. Chironomidae larvae were collected from four lakes of the Chingaza paramo during the dry season, between April and May of 2 016. The feeding habits of larvae were evaluated by analyzing gut contents following standard methods. Each genus was assigned to trophic guilds (carnivore, detritivore and algivore) and the diet overlap was estimated using the Pinka's index. A total of 1 003 individuals were collected and nine genera were identified. Larvae consumed mainly fine particulate organic matter (FPOM), algae, macrophyte fragments, macroinvertebrates, and animal tissues. FPOM was the main feeding resource of detritivores. The analysis of diets showed a high affinity of each genus for a single trophic guild and most of the genera were generalist in the use of resources. For all lakes, high levels of diet overlap were observed among genera and trophic guilds, mainly among detritivores. Our results suggested that Chironomidae larvae of these lakes presented well differentiated trophic habits, and showed a moderate diet overlap within detritivores and carnivores.

scholarly journals Limitations in the assessment of radon dose: the role of activity measurements in the human body

2019 ◽  
Vol 24 ◽  
pp. 92
Author(s):  
J. Kalef-Ezra ◽  
S. Valakis
Keyword(s):  
Effective Dose ◽  
Human Body ◽  
Detection Efficiency ◽  
Medical Physics ◽  
High Sensitivity ◽  
Temporal Variations ◽  
Cold Season ◽  
Whole Body ◽  
Group I ◽  
Activity Measurements

Radon-222 is classified in the Group I of the human carcinogens. The in situ decay of inhaled 222Rn and its short-lived decay products (T1/2 <30 min) is the main source of radiation burden to the general population of natural origin. The corresponding effective dose is routinely calculated as the product of the 222Rn concentration in air, a predetermined dosimetric constant and a factor that depends on the space type (e.g. residential or public building, cave, mine, etc). However, in practice, there are large spatial and temporal variations in the activity ratio of each progeny to 222Rn in air, the characteristics of the progeny carrying particles and the metabolism of each progeny depending on air quality, as well as differences in the anatomic and physiological characteristics between individuals, that vary substantially even with time. Therefore, the currently employed dosimetric approach may introduce large uncertainties. In the hypothetical case of acute deposition and full retention in the human body of equal activities of all 222Rn progeny, about 93% of the effective dose is due to the decaying 214Po. The 214Po activity can be assessed by measurement of its γ-emitting precursor, 214Bi, which is in full equilibrium with 214Po in the human body. The 214Bi activity can be measured using a high-sensitivity whole-body counter with high counting uniformity, such as the one in use at the Ioannina University Medical Physics Department. Its detection efficiency and its dependence on body shape and size were assessed by Monte Carlo simulations. Measurements carried out in healthy adult volunteers residing at a short distance from the counter, indicated a mean total body 214Bi activity (TBBi) of ~100 Bq during the cold season of the year and lower during the hot one. Higher mean TBBi levels were found in male than in female adults. Therefore, TBBi measurements may allow for accurate radon-related risk assessment on individual base.

scholarly journals Diet Composition and Seasonal Fluctuations in the Feeding Habit of Snow Barbel (Schizothorax plagiostomus) in River Indus, Pakistan

2018 ◽  
Vol 46 (1) ◽  
pp. 8
Author(s):  
Muhammad Qayash Khan ◽  
Muhammad Zubair Anjum ◽  
Shamim Akhter ◽  
Irfan Khattak ◽  
Abid Ali
Keyword(s):  
Diet Composition ◽  
Feeding Activity ◽  
Fish Fauna ◽  
Feeding Habit ◽  
Gut Contents ◽  
Catch Per Unit Effort ◽  
Food Items ◽  
Unit Effort ◽  
Significant Difference ◽  
River Indus

Background:Schizothorax plagiostomus is widely distributed in river Indus and is most important food fish in Pakistan. The feeding habit of fish is directly related to the size of fish, its metabolic rate and environmental temperature. The accurate description of fish diet and feeding habit is a very important aspect in fisheries management for the purpose of species conservation, breeding and culture. The present work was aimed to investigate the specie abundance, the diet composition and seasonal variations in the feeding habit of Snow barbell Schizothorax plagiostomus.Materials, Methods & Results: A total of 1799 fish specimens were caught at the confluence of six tributaries along river Indus at Indus Kohistan, northeastern Pakistan. The fish were collected by 5-panels of gill net during first week of each month. The site specific Catch Per Unit Effort (CPUE) and season specific CPUE of fish fauna were assessed. For the gut content analysis 240 samples (99 male and 141 females) of S. plagiostomus were selected on monthly basis. Frequency of occurrence method and volumetric method were applied to record the different food items in the gut of S. plagiostomus. The physico-chemical parameters, NO3 concentration and dissolved Co2 of water from different localities of river Indus were recorded month wise by Hach sensION 156 meter, Horiba LAQUA Nitrate Meter and EA80 meter respectively. Significant difference was observed in water temperature during the four seasons. Except alkalinity no other water parameter showed significant variation across different localities. The results showed that highest Mean CPUE was observed for Darel Stream (0.55) and lowest for Jalkot stream (0.26). Peak abundance of fish was recorded in the month of November with a mean catch of 44.50, mean CPUE of 0.74 and mean Kruskal-Wallis rank value of 63.25. Spirogyra and Ulothrix occurred as maximum food items in the gut of S. plagiostomus during summer while their minimum amount occurred during autumn. According to the ranking index spirogyra and ulothrix ranked higher with significant difference in comparison to other food items. The results showed that S. plagiostomus is phytophagous in its feeding habit, which consumed mainly algae attached to stones and pebbles during the whole year. However, the presence of some secondary items such as animal matter, detritus, sand and mud might be due to the distinct availabilities of food along the seasons. The highest feeding activity of S. plagiostomus was recorded during summer while the lowest one occurred during autumn, spring and winter. Discussion: Catch per unit effort (CPUE) is an indirect measure of the abundance of a target species. It is used as an index of stock abundance in fisheries and conservation biology. During the study low fish fauna was found in River Indus as reported previously. Majority of the fish occurred in snow fed river tributaries in the study area as these tributaries are comparatively less turbulent. Previous studies have also recorded that Schizothoracine generally prefer clean waters. The present findings of gut contents analysis showed clearly that S. plagiostomus is a phytophagous fish which scrap and consumed spirogyra and ulothrix attached to stones and pebbles. Earlier it was reported that mouth of S. plagiostomusis is inferior, wide, with deep lower jaw having keratinized cutting edge and the lower lip is folded and expanded with numerous papillae making it best suited for scrapping algae attached to stones and pebbles. The highest feeding activity was observed during warmer months as compared to cold months. S. plagiostomus spawn twice in a year in autumn and in spring. The highest feeding activity of S. plagiostomus seems to be link with a reflex of recovery strategy due to physiological process of gonadal development.

scholarly journals The Temporal Variation of the Microclimate and Human Thermal Comfort in Urban Wetland Parks: A Case Study of Xixi National Wetland Park, China

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1322
Author(s):  
Zhiyong Zhang ◽  
Jianhua Dong ◽  
Qijiang He ◽  
Bing Ye
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Temporal Variations ◽  
Cold Season ◽  
Scientific Data ◽  
Cold Weather ◽  
Recreational Activities ◽  
Human Thermal Comfort ◽  
Island Effect ◽  
Urban Wetland

As an important part of the ecological infrastructure in urban areas, urban wetland parks have the significant ecological function of relieving the discomfort of people during their outdoor activities. In recent years, the specific structures and ecosystem services of urban wetland parks have been investigated from different perspectives. However, the microclimate and human thermal comfort (HTC) of urban wetland parks have rarely been discussed. In particular, the changing trends of HTC in different seasons and times have not been effectively presented. Accordingly, in this research, a monitoring platform was established in Xixi National Wetland Park, China, to continually monitor its microclimate in the long term. Via a comparison with a control site in the downtown area of Hangzhou, China, the temporal variations of the microclimate and HTC in the urban wetland park are quantified, and suggestions for clothing are also provided. The results of this study demonstrate that urban wetland parks can mitigate the heat island effect and dry island effect in summer. In addition, urban wetland parks can provide ecological services at midday during winter to mitigate the cold island effect. More importantly, urban wetland parks are found to exhibit their best performance in improving HTC during the daytime of the hot season and the midday period of the cold season. Finally, the findings of this study suggest that citizens should take protective measures and enjoy their activities in the morning, evening, or at night, not at midday in hot weather. Moreover, extra layers are suggested to be worn before going to urban wetland parks at night in cold weather, and recreational activities involving accommodation are not recommended. These findings provide not only basic scientific data for the assessment of the management and ecological health value of Xixi National Wetland Park and other urban wetland parks with subtropical monsoon climates, but also a reference for visitor timing and clothing suggestions for recreational activities.

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