Seasonal Ponds Research Articles

Distributional ecology of snails (Gastropoda: Mollusca) in seasonal ponds of Tamil Nadu, South India

The present study was focused to examine diversity and distributional pattern of freshwater snails and to identify the schistosome infected snails in ten different ponds of Madurai district, Tamil Nadu, South India. Snails were collected from native substrates in ponds using dip net from Madurai North, Tamil Nadu province of south India and microscopic examination for detecting cercariae larvae in snails were assessed. In total, 1250 individuals belonging to six species under five families of freshwater snails were collected. The alpha and beta diversity analyses were calculated for estimating the diversity of snails. The cercariae infection was observed in four collected freshwater snail species. Of four infected snails, Lymnaea luteola had the highest percentage of cercariae infection. Statistical tests showed that the environmental factors of total dissolved solids, pH and salinity were significantly related with snail distribution and cercariae infection rather than spatial factor. The study demonstrated that the salinity, conductivity and total dissolved solids of pond water play a key factor for the distribution of snails and cercariae infection. The findings of our study will improve the understanding of the dynamics of schistosomiasis transmission and would ease the implementation of integrated disease control measures based on ecological knowledge of schistosomiasis vector in Madurai and Tamil Nadu zones.

Simulated chorus attracts conspecific and heterospecific Amazonian explosive breeding frogs

AbstractIn tropical regions, some anuran species breed "explosively", reproducing in massive and highly diverse aggregations during a brief window of time. These aggregations can serve as acoustic beacons, attracting other anurans toward seasonal ponds. We hypothesize that conspecific and heterospecific calls play a role in navigation toward ponds and synchronization of reproduction among species. We simulated a chorus of two species (Trachycephalus coriaceus and Chiasmocleis shudikarensis) with contrasting call characteristics (low‐frequency vs. high‐frequency) and reproductive strategies (strict pond breeder vs. opportunistic) near known explosive breeding sites. We predicted that choruses of T. coriaceus are more attractive to heterospecifics than of C. shudikarensis because the first provides a more reliable indicator of a suitable breeding pond and a better long‐distance signal. We found that both choruses attracted conspecific frogs to the playback outside a natural breeding event. As predicted, heterospecifics were attracted only by low‐frequency calls of T. coriaceus that breeds exclusively in large ponds, but not by higher frequency calls of C. shudikarensis that also breeds in small pools not suitable for other species. Our study presents the first experimental evidence that tropical explosive breeding anurans are attracted to conspecific and heterospecific choruses. The contrasting effect of the playback of the two species on heterospecifics suggests that the attractive effect of a chorus depends on the reproductive strategy of both the sender and the receiver. Given the abundance and diversity of communities in tropical ecosystems, the use of heterospecific acoustic cues may prove widespread and requires further investigation.Abstract in Portuguese is available with online material.

A predictive model for seasonal pond counts in the United States Prairie Pothole Region using large-scale climate connections

The Prairie Pothole Region (PPR), located in central North America, is an important region hydrologically and ecologically. Millions of wetlands, many containing ponds, are located here, and they serve as habitats for various biota and breeding grounds for waterfowl. They also provide carbon sequestration, sediment and nutrient attenuation, and floodwater storage. Land modification and climate change are threatening the PPR, and water and wildlife managers face important conservation decisions due to these threats. We developed predictive, multisite forecasting models using canonical correlation analysis (CCA) for pond counts in the southeast PPR, the portion located within the United States, to aid in these important decisions. These forecast models predict spring (May) and summer (July) pond counts for each region (stratum) of the United States Fish and Wildlife Service’s pond and waterfowl surveys using a suite of antecedent, large-scale climate variables and indices including 500 millibar heights, sea surface temperatures (SSTs), and Palmer Drought Severity Index (PDSI). Models were developed to issue forecasts at the start of all preceding months beginning on March 1st. The models were evaluated for their performance in a predictive mode by leave-one-out cross-validation. The models exhibited good performance (R values above 0.6 for May forecasts and 0.4 for July forecasts), with performance increasing as lead time decreased. This simple and versatile modeling approach offers a robust tool for efficient management and sustainability of ecology and natural resources. It demonstrates the ability to use large-scale climate variables to predict a local variable in a skilful way and could serve as an example to develop similar models for use in management and conservation decisions in other regions and sectors of the environment.

Physics and geochemistry of lakes in Vestfjella, Dronning Maud Land

AbstractShallow Antarctic surface lakes belong to the most extreme aquatic environments on the Earth. In Vestfjella, proglacial surface lakes and ponds are characterized by a 2–5 month long period with liquid water and depths < 2 m. We give a detailed description of nine seasonal lakes and ponds situating at three nunataqs (Basen, Plogen and Fossilryggen) in western Dronning Maud Land. Their physical and geochemical properties are provided based on observations in four summers. Three main ‘lake categories‘ were found: 1) supraglacial lakes, 2) epiglacial ponds and 3) nunataq ponds. Category 3 lakes can be divided into two subgroups with regards to whether the meltwater source is glacial or just seasonal snow patches. Supraglacial lakes are ultra-oligotrophic (electrical conductivity < 10 μS cm−1, pH < 7), while in epiglacial ponds the concentrations of dissolved and suspended matter and trophic status vary over a wide range (electrical conductivity 20–110 μS cm−1, pH 6–9). In nunataq ponds, the maxima were an electrical conductivity of 1042 μS cm−1 and a pH of 10.1, and water temperature may have wide diurnal and day-to-day fluctuations (maximum 9.3°C) because snowfall, snow drift and sublimation influence the net solar irradiance.

Montane seasonal wetlands: an inventory of its associated flora in Parque Estadual do Ibitipoca, southeast Brazil

Abstract The aim of the present study was to perform the floristic survey of the wetlands of the Parque Estadual do Ibitipoca (PEIB), comparing them regarding richness, floristic composition and life forms, based on monthly expeditions to collect vascular plants. Eighty-one (81) species were found in the moist grassland, most of them being endemic to Brazil and included in 55 genera and 21 families. The most representative families were Asteraceae (22 spp.), Melastomataceae (nine spp.), Xyridaceae (seven spp.), Poaceae and Orchidaceae (six spp. each), totalizing 62% of the sampled species. Twenty-seven (27) species were found in the seasonal pond, distributed in 23 genera and 11 families. Families with the highest specific richness were Poaceae (eight spp.), Cyperaceae and Asteraceae (five spp. each), totalizing 67% of the sampled species. There was a predominance of hemicryptophyte life form (nearly 43% of the moist grasslands and 63% of the seasonal pond) in both areas. The floristic analysis results showed great importance to conservation with 22% of species under some threatened category, 12 species endemics to Minas Gerais state and one new species of Cyperaceae. Furthermore, only five species occur in both wetland types (5.1% of the species richness).

Analysis of Pond Fisheries in Climate Change Scenario in the Haor Region of Bangladesh

Aims: To identify the potential environmental impacts and influence of climate change on the pond fishery in haor region and impact of exotic species on the indigenous species through aquaculture.
 Study Design: An investigation on the influence of the pond fishery approach to determine whether the approach is successful with respect to the climate change impacts in the haor area.
 Place and Duration of Study: The study sites are located in five haor districts in Bangladesh for a period of one-year (May 2018 – April 2019) covering HILIP working area.
 Methodology: The study includes collection and analyses of both quantitative and qualitative data. For quantitative study, 92 sample households in 58 unions of 28 upazilas (sub-districts) in five project districts were randomly selected. Fish catch data, including information on species composition, production and sale were collected from perennial and seasonal ponds. The qualitative primary data obtained through in-depth interviews, key informants interviews and focus group discussions have been used in this paper.
 Results: Fish production was found to be better at perennial ponds, but not significantly more than that in the seasonal ponds. However, biodiversity was found to be better in seasonal ponds and greater than that in the perennial ponds. The findings clearly support the observation that pond fish culture is an attractive activity for haor people, especially those who are able to run both perennial and seasonal ponds and manage minimum feeding requirements, maintain those and market the outputs effectively. The present study fills gaps in existing knowledge of fish pond culture diffusion in haor region of Bangladesh.
 Conclusions: Pond fishery appears to perform better so, aquaculture production would mitigate some lost capture fisheries in the haor area of Bangladesh. Existing cultural practices could support experimentation and learning under future initiatives in the haor area. Pond fishery in the haor area mainly has an income-generating feature and less probability of being affected by climate change impacts. However, future initiatives should emphasize on culturing fish, which has the potential of balancing the haor ecosystem.
 Aims: To identify the potential environmental impacts and influence of climate change on the pond fishery in haor region and impact of exotic species on the indigenous species through aquaculture.
 Study Design: An investigation on the influence of the pond fishery approach to determine whether the approach is successful with respect to the climate change impacts in the haor area.
 Place and Duration of Study: The study sites are located in five haor districts in Bangladesh for a period of one-year (May 2018 – April 2019) covering HILIP working area.
 Methodology: The study includes collection and analyses of both quantitative and qualitative data. For quantitative study, 92 sample households in 58 unions of 28 upazilas (sub-districts) in five project districts were randomly selected. Fish catch data, including information on species composition, production and sale were collected from perennial and seasonal ponds. The qualitative primary data obtained through in-depth interviews, key informants interviews and focus group discussions have been used in this paper.
 Results: Fish production was found to be better at perennial ponds, but not significantly more than that in the seasonal ponds. However, biodiversity was found to be better in seasonal ponds and greater than that in the perennial ponds. The findings clearly support the observation that pond fish culture is an attractive activity for haor people, especially those who are able to run both perennial and seasonal ponds and manage minimum feeding requirements, maintain those and market the outputs effectively. The present study fills gaps in existing knowledge of fish pond culture diffusion in haor region of Bangladesh.
 Conclusions: Pond fishery appears to perform better so, aquaculture production would mitigate some lost capture fisheries in the haor area of Bangladesh. Existing cultural practices could support experimentation and learning under future initiatives in the haor area. Pond fishery in the haor area mainly has an income-generating feature and less probability of being affected by climate change impacts. However, future initiatives should emphasize on culturing fish, which has the potential of balancing the haor ecosystem.

Factors Affecting Soil Total Mercury in Seasonal Pond Basins within a Northern Hardwood Forest in Minnesota, USA

Forest canopies are sites for mercury (Hg) deposition, and forests can act as Hg sources to downstream aquatic environments. This study examined soil total Hg (THg), carbon (C), and nitrogen (N) to 15 cm in 10 seasonal pond basins in a northern hardwood forest in Minnesota. Pools (mass per area) and concentrations (mass per soil mass) of THg to 15 cm were lower in uplands than in ponds, indicating downslope transport. In uplands, THg concentrations were the same at 0‐ to 2‐cm and 2‐ to 5‐cm depths and then decreased, whereas THg density (mass per volume) peaked at 2 to 5 cm, highlighting the importance of bulk density on mass. Carbon and N trends were similar to THg. Apart from pond centers, strong positive relationships between THg and C were observed. Upland slope length, graminoid cover, basin area, and tree height accounted for over half of THg variance at pond edge. Understanding the distribution, trends, and contributing factors of soil THg can further efforts toward immobilization and sequestration, thus minimizing the potential for bioaccumulation.Core Ideas THg uniform among basins in uplands with pond centers variable by substrate. THg greatest at pond center and uniform among upland landscape positions. Positive THg relationships with C and N, except organic pond centers. Upland THg concentration peaked at 0 to 5 cm, with mass peaking at 2 to 5 cm. Fifty‐six percent of THg pool was explained by slope length, graminoid cover, basin area, and tree height.

Assessment of physico‐chemical properties of water and phytoplankton bloom formation in a eutrophic pond using multivariate analysis

AbstractAn investigation of the water chemistry and phytoplankton bloom formation characteristics of a seasonal earthen pond located in the Alappuzha District, Kerala (India) was carried out during November 2011 to May 2012. Twelve important physico‐chemical parameters (temperature, Secchi disc transparency, pH, electrical conductivity EC), dissolved oxygen (DO), biochemical oxygen demand (BOD), ammonia‐nitrogen, nitrite‐nitrogen, nitrate‐nitrogen, total phosphorus (TP), dissolved iron and chlorophyll a related to phytoplankton growth in the pond were the focus of the present study. Chlorophyll a was used as a measure of phytoplankton biomass. The pond developed subsurface phytoplankton blooms of Chlorella vulgaris, Aphanothece sp., Leptosira sp., Lepocinclis globulus and Lepocinclis fusiformis. Visible scums of Lepocinclis globulus and Euglena proxima was also observed during March 2012. Principal component analysis was performed to understand the biochemical processes in the pond ecosystem leading to the Euglena spp. bloom.

Physicochemical Analysis of Surface Water Quality on Seasonal Ponds along Riverine Communities

Water as a resource is essential to human life beside been the most fundamental resource for his socio-economic development. Within the land-lock Northern Nigeria, the surface water and groundwater resource remain the only source of the region fresh water. With contemporary pronounced effects of climate change as well as various anthropogenic activities, there is consequential rise in demand of fresh water. Consequently, both quantity and quality of fresh water resource is threatened largely due to recent population explosion. However, most developing regions of the world require new methods and innovative approaches for fresh water management, conservation, and judicious uses. Nonetheless, the dependence of arid and semi-arid regions on irrigation holds a special place in the water scarcity and management debates. This study was carried out along the river Anumma in Ngalda area of Yobe State, Nigeria. The study revealed that there is an active pollution largely associated to higher fertilizers and pesticides residues. The study also reaffirmed the calls for immediate action and adoption of sustainable agricultural practices along riverine communities in order to safe-guide the region most precious resource (water).

Fish Fry Lake: Perspectives from an Inventor on the Application of Created Floating Islands for Water Quality Renovation

Today Fish Fry Lake is a highly productive wild fishery, and also a long-term experiment tracking how the resource of nonpoint nutrient-loaded water can be optimally managed. The Fish Fry Lake story has relevance to water stewardship across much of the developed world where water quality is impacted by agricultural-based nutrient loading. Fish Fry Lake is located on the east side of Yellowstone County in south-central Montana. The lake covers 6.5 surface acres, is 28 feet deep at its deepest point, and contains about 55 acre-feet of water at full pool. Groundwater influenced by agriculture infiltrates to the lake and discharges at a typical rate of 65-85 gallons per minute. When the lake was converted from a seasonal pond to a perennial one in 2005, it displayed the typical attributes of a eutrophic waterway. The lake surface was occasionally completely covered with filamentous blue-green algae, with occasional patches of cyanobacteria.

The impact of phenology on the interaction between a predaceous aquatic insect and larval amphibians in seasonal ponds

Phenology has an important effect on the life strategies of species that live in temporary waters. Predaceous aquatic insects are key components of communities associated with seasonal ponds. Since the life cycles of these predators and their prey are unusual in that they occur at different moments of the pond hydroperiod, differences in temporal overlap could change the strength of their interactions. This study analyzed the phenology of the giant water bug Belostoma bifoveolatum and its prey. Breeding phenology, nymph population, and prey phenology were studied extensively in three wetlands during the spring season. Experimental trials were carried out to evaluate prey consumption and prey preference. The results showed a strong overlap in phenology between the water bug and the Pleurodema thaul frog. The timing of tadpole and water bug nymph hatching could ensure high survival levels of the early immature stages of this insect. As giant water bugs develop, their prey selectivity experiences a shift—older nymphs and adults having a higher impact on tadpoles. The fluctuating climate of the Patagonian region probably influences the phenology of predator–prey assemblages in seasonal communities, and may have the potential to drive feeding performance and the strength of interspecific interactions.

Classification of Small Seasonal Ponds Based on Soil–Water Environments in the Cuvelai Seasonal Wetland System, North-Central Namibia

The objectives of this study were to classify the small seasonal ponds that develop in the Cuvelai Seasonal Wetland System in north-central Namibia based on soil physicochemical properties so that potential agricultural uses of the ponds could be assessed. Satellite imagery was used to examine the relationships between soil characteristics and the probability of water presence in the region. Soil samples were collected from 66 ponds at three sites and their physicochemical properties and levels of salt accumulation were investigated. Soil data were analyzed by using principal component analysis and cluster analysis. The ponds were classified into four types based on soil properties. Type A accounted for 20% of the ponds and was characterized by high levels of clay, silt, total N, and exchangeable Ca, Mg, and K. Type B accounted for 14% of the ponds and was characterized by high values of organic C, C/N ratios, and available P. Type C accounted for 20% of the ponds, and this type featured high levels of salinity and sodicity. The remaining ponds were classified as Type D. If these seasonal ponds are to be considered for crop production, Type C should be avoided and Type D would require soil fertility improvements.

Recent groundwater and lake-stage trends in Cape Cod National Seashore: relationships with sea level rise, precipitation, and air temperature

AbstractHydrological features on Cape Cod, Massachusetts, USA, include groundwater, freshwater lakes, permanent and seasonal ponds, streams, and estuaries. Rainfall and evaporation/evapotranspiration have long been considered the dominant factors influencing both lake and groundwater levels in this sole-source, unconfined aquifer. However, increases in sea level may also have an effect, especially on this narrow peninsula with a sandy substrate of high permeability. In this study, we analyzed trends between 2000 and 2017 in eleven groundwater wells and nine kettle ponds situated with Cape Cod National Seashore (CCNS). We further explored relationships of these hydrologic variables with local precipitation, temperature and sea level during this period. The results suggest that while precipitation patterns influence seasonal and inter-annual variability, it appears that sea level rise (SLR) may be partially responsible for driving the longer-term trend of rising groundwater levels in several wells. Pond stages did not exhibit any statistically significant trends, and responded more to precipitation during this period of time. Notwithstanding, further acceleration of SLR, along with potential changes in precipitation patterns, can alter the freshwater hydrology of CCNS that may subsequently have biological, chemical, and physical effects throughout these systems.

Polyculture of Vietnamese koi (Anabas testudineus): Emphasis on Seasonal Mini Water Ponds in Semi- Arid Zone of Bangladesh

Polyculture of Vietnamese koi (Anabas testudineus): Emphasis on Seasonal Mini Water Ponds in Semi- Arid Zone of Bangladesh

An endangered new species of seasonal killifish of the genus Austrolebias (Cyprinodontiformes: Aplocheiloidei) from the Bermejo river basin in the Western Chacoan Region.

Austrolebias wichi, new species, is herein described from seasonal ponds of the Bermejo river basin in the Western Chacoan district in northwestern Argentina. This species was found in a single pond, a paleochannel of the Bermejo River, which is seriously disturbed by soybean plantations surrounding it. Despite intensive sampling in the area, this species was only registered in this pond where it was relatively scarce. Therefore, we consider this species as critically endangered. This species is the sister species of A. patriciae in our phylogenetic analyses and is similar, in a general external aspect, to A. varzeae and A. carvalhoi. It can be distinguished among the species of Austrolebias by its unique color pattern in males. Additionally, from A. varzeae by presenting a supraorbital band equal or longer than the infraorbital band (vs. shorter) and from A. patriciae by the convex dorsal profile of head (vs. concave). Further diagnostic characters and additional comments on its ecology and reproduction are provided.

Small scale fish farming in seasonal ponds in Brazil: technical and economic characterization

The inclusion of aquaculture in household agriculture has been related as an opportunity of product and income diversification as wells as to increase food security for farmers. Small-scale fish production has increased in Brazil, even in regions with a pronounced dry season. However, there is no information about the characteristics and technical and economic viability of aquaculture under these conditions. This study was carried out with the objective to characterize the production of tambatinga (Colossoma macropomum × Piaractus brachypomus) in water deficit conditions in Tocantins State, Brazil. The study revealed that it is technically possible and economically feasible to produce tambatinga in seasonal ponds. Worth noting was the adaptability of the hybrids which showed a suitable growth and tolerance to the poor water quality conditions. However, in order to achieve production success and financial returns, the adoption of the following procedures are suggested: a) fish stocking as soon as the rainy period starts, b) use of larger juveniles to achieve a higher final weight, c) adoption of pond liming and fertilizing practices previous to stocking, d) water quality monitoring, e) evaluate fish growing performance, f) partial harvesting during the production cycle, and g) total harvesting at the end of the rainy season.

Amphibians distribution and habitats in the southwestern region of Saudi Arabia.

This study surveyed 205 wetland sites in the Southwestern Saudi Arabia. We found seven species of amphibians (Anura), which belong to four families: Bufonidae; which includes four species, Sclerophrys tihamica; S. Arabica, Duttaphrynus dhufarensis, and Bufotes viridis; Hylidae, represented by only one species, the tree frog Hyla savignyi; Ranidae, which represented by one species, Pelophylax ridibundus and finally the Dicroglossidae, represented by one species, Euphlyctis ehrenbergii. The reasonable amount of rain received in southwest Arabia, and habitat diversity contribute to the relative abundance of amphibians in the region. Five types of wetland habitats were found in the study area. Valley streams, irrigated farms, seasonal ponds, dam reservoir and lagoons of treated sewage water. The current study revealed the wide spread of amphibians in southwestern Saudi Arabia than what had been reported earlier and confirmed the presence of the Bufotes viridis at three new sites in Asir Heights. It also showed the wide spread of S. arabica in all types of habitats in the southwestern region of Saudi Arabia. Habitat degradation was evident in the region, which might lead to species loss.

Seasonality, water use and community management of water systems in rural settings: Qualitative evidence from Ghana, Kenya, and Zambia

The sustainability of rural, community-managed water systems in sub-Saharan Africa depends in part on the ability of local water committees to repair breakdowns and carry out the operation and maintenance (O&M) of the system. Much of sub-Saharan Africa has two distinct seasons that affect the availability of water sources and how people use water. Little is known about how seasonality affects water system management. This qualitative study is based on 320 interviews and focus group discussions and examines the effects of season on community water use and management in Ghana, Kenya and Zambia. Participants revealed that seasonality affects water availability, water system breakdowns, resource mobilization, committee activity, and external support availability. In the rainy season, participants typically reported spending less time and money on water collection because rainwater harvesting and seasonal streams, ponds, wells and reservoirs are available. In the dry season, people used improved groundwater sources more often and spent more money and time collecting water. Although seasonal changes in household water demand and use have been examined previously, our data suggest that seasonality also influences community management through differential water system use, system breakdowns and management characteristics. We found that water committees generally have less money, time and access to external support during the rainy season, making them less able to carry out O&M. Our results suggest that community engagement should take place over a long period of time so that seasonal patterns in management can be understood and incorporated into water committee training. External support actors should make a more targeted effort to understand the cultural and economic patterns in a community in order to train committees with appropriate management strategies.

Review of the family Rivulidae (Cyprinodontiformes, Aplocheiloidei) and a molecular and morphological phylogeny of the annual fish genus Austrolebias Costa 1998

ABSTRACT The family Rivulidae is the fourth most diverse clade of Neotropical fishes. Together with some genera of the related African family Nothobranchiidae, many rivulids exhibit a characteristic annual life cycle, with diapausing eggs and delayed embryonic development, which allows them to survive in the challenging seasonal ponds that they inhabit. Rivulidae also includes two species known as the only the self-fertilizing vertebrates and some species with internal fertilization. The first goal of this article is to review the systematics of the family considering phylogenetic relationships and synapomorphies of subfamilial clades, thus unifying information that is dispersed throughout the literature. From this revision, it is clear that phylogenetic relationships within Rivulidae are poorly resolved, especially in one of the large clades that compose it, the subfamily Rivulinae, where conflicting hypotheses of relationships of non-annual and annual genera are evident. The second goal of this work is to present an updated phylogenetic hypothesis (based on mitochondrial, nuclear, and morphological information) for one of the most speciose genus of Rivulidae, Austrolebias. Our results confirm the monophyly of the genus and of some subgeneric clades already diagnosed, but propose new relationships among them and their species composition, particularly in the subgenus Acrolebias.

Stocking density of threatened cat fish Heteropneustes fossilis (Bloch, 1792) in seasonal ponds of Rajshahi, Bangladesh

An attempt was made to evaluate the effect of stocking density on the growth of Heteropneustes fossilis for a period of six months reared in earthen ponds at Rajshahi University Campus. H. fossilis fingerling were stocked at the rate of 320, 280, 240/dec in treatment T1, T2 and T3, respectively, The treatments had significant effects on the weight gain, length gain, ADG, SGR parameters among the treatments. Highest weight gain (45.90g) was observed in T3 and lowest (36.97g) in T1. Significant (P<0.05) highest yield was obtained in case of T2 and T3 and it was 2686.80 kg/ha and 2343 kg/ha, respectively. Higher net benefits (5,18519.91TK/ha) were obtained from treatment T2, than from treatments T1 and T3, water temperature, transparency, pH and dissolved oxygen did not differ significantly (P>0.05) among the treatments depicting the suitable range for fish culture. The plankton levels in all the treatments were found to be at optimum state. Final length, final weight and survival of fingerlings followed the same trends of weight gain. Cost benefit ratio was also highest (1:0.93) in T2, followed by T3 and T1. Overall, highest growth, fish yield survival (95.67%) rate and net benefits of fingerlings were obtained at a density of 280/dec (69, 160 individuals/ha) in treatment T2 were recorded.Bangladesh J. Sci. Ind. Res. 52(4), 253-262, 2017