Sustainability impacts of ecosystem approaches to small-scale aquaculture in Bangladesh

This study explores the sustainability impacts of adopting an ecosystem approach in underutilized homestead ponds (ecoponds) operated by women in Bangladesh. Households with ecoponds have significantly higher fish productivity, fish diversity, and income generation potential compared to households with similar underutilized ponds. Furthermore, certain dimensions of women’s empowerment are improved at the individual and household level (e.g., control of income and productive assets), without, however, addressing wider structural inequalities. Food security impacts are rather inconclusive, as despite the higher consumption of more diverse fish species among ecopond households, there is no significant effect on overall dietary diversity.

Characteristics of perch fish diet in small lake of Lake Onega catchment area

Fish feeding process is studied as one of the links in the transformation of the energy of a water reservoir, as one of the factors that determine the ecology of fish and make an imprint on the morphology, physiology and behavior of fish, or as one of the criteria, which help the most rationally use natural resources of the water bodies. The results of work carried out by the Northern Water Problems Institute (NWPI KarRC RAS) and Petrozavodsk State University (PetrSU) within the framework of state assignments, forecast problems and economic contractual topics on assessing the nutrition of perch species (perch, ruff) in some lakes of the Konchezero group (South Karelia), in particular Lake Munozero, which is part of the lower reaches of the river Shuya belonging to the catchment area of Lake Onega. The work was carried out by the experts from the IWPS KarRC RAS and PetrSU in 2018-2020. Its main hydrological and ichthyological indicators have been studied. The reconnaissance fish productivity of Lake Munozero based on the development of the forage base at the present stage is estimated as 9 kg/ha. The feeding spectra of ruff and perch in the lake overlap only with respect to eggs, the ruff using eggs more actively. Predation is peculiar only to perch, while even fish whose size is less than 14 cm (the average size of the transition to predation for Karelia) hunt at a time when there is a lot of other food in the reservoir. As the perch passes to summer feeding, its diet becomes more diverse. Some benthic organisms are replaced by others, an air fraction appears, the perch's diet includes fish in summer and spring; nutrition becomes more active: the average stomach fullness index increases from 7.3 to 145.6‰.

Use of hulless oats in feeding of pedigree 1+ carp as an effective method for ensuringthe physiological needs of fish

Purpose. To study the effect of addition of hulless oats during the growing period on the qualitative and quantitative indicators of replacement-brood stock of carp. Methodology. The replacement-brood stock of Lubin intra-breed type of Ukrainian scaly carp strain, which were kept in ponds of State Enterprise Experimental Fish Farm of Lviv Research Station of the Institute of Fisheries of the National Academy of Agrarian Sciences of Ukraine (IFNAASU) was used for the study. The stocking density was 1000 fish/ha. The experiment was based on four experimental groups. Carps of the first experimental group were fed during the entire growing period with a feed mixture with the addition of hulles oats in the amount of 10 %, while carps of the second group were fed with a feed with the addition of 30 % of hulless oats. The third experimental group received a feed mixture in June – July, and hulless oats in August. The control group of carp was fed with the feed mixture throughout the entire growing period. The stocking density of fish was 1000 fish/ha. Piscicultural studies were conducted in accordance with current methods. Sampling of water for chemical analysis and its processing in the laboratory was carried out according to O. Alokin according to the Standard of the Ministry of Agrarian Policy of Ukraine. Haemoglobin content was determined by the haemoglobin-cyanide method. Blood erythrocytes were counted in a Goryaev chamber. Abundance and weight of natural feeds in ponds were determined according to I.A. Kyseliov, V.I. Zhadin. Zooplankton biomass was determined using tables of individual weights of F.D. Mordukhai-Boltovskoi. Analytical processing of the material was performed using MS Excel. The criteria for the analysis of indicators were their mean (M) and mean deviation (m). Findings. Peculiarities of growth, development of carp and efficiency of feed usage with the addition of hulless oats on the background of similar satisfactory growing conditions were studied. It was found that additional feeding of carp with hulless oats at an amount of 30% was effective. In particular, its addition resulted in an increase in individual weight by 31.1% and survival rate by 2.33%. Studies of the physiological functions of the body of experimental fish during the growing period after adding the hulless oats into the main diet provided an opportunity to recommend its use in the feeding process of age–1+carp in order to increase fish productivity. Originality. The advisability of using hulless oats in the feeding of replacement-brood stock of juvenile carp was studied in Ukraine for the first time. The analysis of productive, physiological and economic indicators has been carried out. Practical value. The results of a comprehensive assessment of piscicultura; and biological parameters provide recommendations for the use of hulless oats in the feeding of replacement-brood stock of juvenile carp. Key words: carp, replacement-brood juvenile stock, feed, feed additives, normalized feeding, physiological needs, fish productivity, feed costs, natural food supply.

Technologies of carp growing and their features

Carp is one of the few fish farms for which a wide range of technologies has been developed: from extensive, with minimal human intervention in the formation of fish productivity of the reservoir, to intensive, with the most controlled production conditions. Carp has many biological features, enhanced by centuries of breeding work, making this fish extremely “technological”, able to more or less fully realize the genetically determined bioproductive properties of different breeding technologies. Technologies for growing commercial carp according to the level of intensification of the production process can be divided into extensive (grazing), semi-intensive, intensive, and continuous, as a distinct type of intensive technology for growing carp in ponds and pools. Extensive technology assumes that the fish will feed exclusively on natural food, zooplankton, and bottom fauna. In this case, the cost of growing carp will be the lowest; the fish will be called “ecological”, but the growth of individuals will be insignificant. Semi-intensive technology assumes that carp feed on natural feeds, and their energy needs are met by providing carbohydrate additives to feed. Intensive technology believes that carp feeding with compound feeds with high protein content is used, which allows achieving productivity of 3–20 tons/ha. This system requires the highest costs, although it gives the highest performance. The pond must provide additional aeration and water flow to prevent contamination of the reservoir and the development of fish diseases. The main disadvantage of popular carp growing technologies is their staging. All operations are carried out strictly one after another in specialized ponds. Moreover, each stage ends with the descent of the tanks, and the fish are transplanted several times from one to another (from spawning to juvenile, from them to nursery). During this, the carp is injured, which negatively affects its productivity and inevitably leads to waste. To remedy this, fish farming is now using continuous rearing technology. The choice of technology for growing carp is a responsible task on which the profitability of fisheries depends.

Pisciculture, biological and physiological indicators of age–1+ carp while adding naked oats into main feeding

The influence of naked oats on pisciculture, biological, hematological and biochemical parameters of commercial carp groups, as one of the components of the feed mixture in different ratios has been studied in the article. The aim of the experiment was to increase the fish productivity of ponds and to reduce feed costs for cultivation by meeting the physiological needs of commercial carp groups when using naked oats in carp feeding. The object of the study was age–1+ carps of Lubin scaly and framed intra-breed type of Ukrainian carp breed. For this purpose, three experimental groups of fish were formed by the method of analogues. Fish of the first experimental group (from July 1) were additionally introduced 30% of naked oats into the main diet, the fish of the second experimental group - 50% of naked oats, the third group was fed a feed mixture without added oats. As a result of the research done, it is proved that the addition of a mixture of naked oats has a positive effect on fish biological and physiological parameters of commercial carp. It was found out that the most effective is the additional feeding of naked oats in the amount of 30%. In particular, when the very amount of naked oats is added to the basic diet, the total fish productivity indicator increases by 7.7% relative to the control pond indicators, and feed costs are lower by 16.7%. The amount of hemoglobin in the blood of the first experimental group was higher relative to the control group, and the number of erythrocytes was significantly higher (P> 0.01). However, in the carp serum of the first experimental group the level of superoxide dismutase (P> 0.02) significantly increased while the level of catalase decreased.

The number of juvenile fish and fish productivity of water bodies of the Ob River basin (Western Siberia): review

The article presents an overview of published materials for the period 1963-2020, containing information on the number of larvae and juveniles of fish in different types of water bodies of the Ob River basin (Western Siberia). Data on the fish productivity of rivers and lakes of the Ob basin for steppe, forest-steppe, taiga and tundra natural zones are presented. The Ob River is the main waterway of Western Siberia. The area of the Ob River basin is 2929,000 km2, the length of the river is 3680 km. The existing pronounced differences in the nature of the relief, climate, soils, waters, vegetation of the natural zones of the Ob basin determine the features of the hydrological regime and the living conditions of hydrobionts. Accordingly, the floodplain of the Ob river with its numerous backwaters, kuryami, lakes, sorami is the main places of spawning and feeding of fish. In the course of generalization of the published materials, information was obtained on the number and features of the distribution of juvenile fish in different types of water bodies (channel pits, floodplain lakes, old trees, sores) of the Ob River basin. The results of studies on determining the fish productivity of rivers and lakes of the Ob basin of steppe, forest-steppe, taiga and tundra natural zones are analyzed.

Cultivation of young-of-the-year carp with the use of chlorella (Chlorella (Beijerinck, 1890)) suspension

Purpose. Investigate ecological conditions and determine fish productivity of ponds when growing young-of-the-year carp using a suspension of chlorella. Methodology. During the study, we used methods generally accepted in hydrochemistry, hydrobiology and fish farming. Findings. The article presents the results of the study on the use of chlorella suspension in the cultivation of carp. It was found that the use of chlorella suspension created favorable hydrochemical conditions resulting in intensive development of zooplankton, which had a positive effect on the growth of young-of-the-year carp and fish productivity of the pond. The development of the natural food supply was sufficient to meet the nutritional needs of juvenile carp. The average seasonal biomass of zooplankton in the experimental pond was 28.68 g/m3 that was 1.5 times higher than in the control. The share of cladocerans in the total biomass of zooplankton in the experimental pond was 76.6%, versus 36.8% in the control. The average biomass of zoobenthos for the growing season in the experimental was 1.3 times higher than in the control, and was formed by chironomid larvae, which are valuable in the food chain. Originality. The study investigated ecological conditions and fish productivity of growing ponds under conditions of the application of cattle manure and suspension of chlorella when growing carp in monoculture. Practical value. It was found that the use of chlorella suspension promotes the intensification of the development of zooplankton organisms in ponds. The obtained data can be used to develop practical recommendations for optimizing the conditions for growing carp seeds and increasing the biological productivity of ponds. Key words: nursery ponds, natural food supply, phytoplankton, zooplankton, zoobenthos, young-of-the-year carp, chlorella suspension, fish productivity.

Different Combinations Of Legowo And Endemic Fish On Rice And Fish Productivity In Minapadi System

Minapadi is a fish rearing system in rice fields that is carried out with rice plants. This study aims to increase the income of farmers with high productivity of rice yields and increase the production of endemic fish. The method used is a Completely Randomized Design (CRD) experiment with 4 treatments and 3 replications. The treatments were: A1B1 (legowo 2:1 and giant prawns), A1B2 (legowo 2:1 and fish exclamation), A2B1 (legowo 4:1 and giant prawns), and A2B2 (legowo 4:1 and fish exclamation). This research was conducted for 90 days in the rice fields of Lango Village, Pante Ceureumen District, West Aceh Regency. Parameters observed were rice productivity, fish growth and business analysis. The results showed that the best treatment was A1B1 (legowo 4: 1 and giant prawns) by producing an average value of rice productivity of 5 kg/plot, and the average value of growth of giant prawns of 3.62 g/head and fish of fish of 37.17 g/head. From the results of this study, the application of the Minapadi system with giant prawns and fish with legowo 4:1 gave a positive impact on the observed parameters (P<0.05) and provided benefits for farmers.

Present Status of Aquatic Resource and Its Catch of Mogra River in Bangladesh

Bangladesh is very rich in aquatic fauna with a biodiversity. The present study, conducted during 2015 to 2019, recorded a total number of 131 spe cies (104 fish, 09 prawn, 01 snail, 04 crabs, and 13 turtles) belonging to 26 families were identified from the Mogra River and its flood plain. About ten types of fishing gears, different crafts, hook and line were found oper ative in the river. Increasing rates of using current jal (16.0-26.40%) and Kapuri jal (11.0-16.70%) were identified as detrimental gears destroyingdifferent species. The fish productivity was decreased dramatically from 170.63±10.81mt to 134.75±8.02 mt with a decreasing percentage of 6.26 to 21.03% within five years. Three important aquatic species turtiles (Cyclemys oldhami, Melanocheelys trjuuga and Morenia petersi) became rare and 17 commercially important aquatic species were at the edge of extinction (critically endangered, CR). From the study, 67 species were recorded inthe endangered (EN) category, 20 species vulnerable status (VU), 11 species lower risk (LR), 07 species Least concern (LC) and 04 Data deficient (DF). To save the existing aquatic species in the studied riverine ecosystem and ensure better livelihood of the fishes, a team of local management committee, similar to the Hilsa fisheries management technology is needed.

Köyceğiz-Dalyan Lagün Ekosistemi Kefal Populasyonlarının Büyüme Performans İndeksleri

As it is common in tropical and temperate zones, mullet species constitute the most important fish species caught along the coast and estuaries of Turkey. In terms of ecology, tourism and and fish productivity (52 kg/ha), Koycegiz-Dalyan Lagoon Ecosystem (KDLES) is the most important lagoon, with a 5500 ha surface area, is the Mediterranean Coast of Turkey. In the dalyan (barrier fish trap) systems; approximately 225 tons (80-405 tons) of mullets are caught to obtain 5 tons of dried fish eggs per year. Seventy percent of fish production in the lagoon is composed of mullets. The mullet samples were collected monthly between October 1992 and September 1994 from eight stations (one of them is a marine station) by trammel nets. The ages were determined using by scales anda ge composition varied form 0 to 6 ages. Species composition of 1159 sampled individuals were proportionally determined as Mugil cephalus 45%, Liza aurata 35%, Liza saliens 14%, Liza ramada 12%, Chelon labrasus 6%. The growth performance indices calculated from von Bertalanffy growth parameters using by all individuals for the M. cephalus, L. aurata, L. saliens, L. ramada and C. labrasus were determined as 2.957, 2.866, 2.692 and 2.719, respectively. The highest growth performance index was calculated for M. cephalus. The growth performance indeces of mullet species in Köyceğiz-Dalyan Lagoon Ecosystem were found around the world averages.