Small Fish Farming Research Articles

Impact of aquaculture on crop productivity in greater Noakhali, Bangladesh

Aquaculture expanded to a great extent in Bangladesh through the conversion of agricultural lands due to high profitability resulting in land-use conflicts. The present study is the first initiative to elucidate the impacts of aquaculture on agricultural farms of greater Noakhali (Noakhali, Feni, and Lakshmipur), Bangladesh. Soil and water samples were drawn from 240 selected farms from fish farms (FF), near land (NL), distance land (DL), and control sites. Soil and water quality parameters were analysed following standard methods. A pre-coded structured questionnaire-based interview of farmers was performed from July 2017 to March 2018. Organic matter, organic carbon, total nitrogen, and pH (soil and water) of FF showed significant influence on its surrounding agricultural lands but sulfur, boron, and potassium did not show such kind of influence in all three districts. Total fish production and gross profit were found higher in large fish farms (32.19 MT/year and 238.24%) compared to medium and small fish farms. NL's total crop production and gross profits also showed the same pattern but DL’s showed the opposite pattern. Aqua farms negatively impacted agriculture in terms of cropping patterns but showed an increasing rate for HYVs (High Yield Variety) of rice in greater Noakhali.

Economic evaluation of Arapaima gigas production in earth ponds: Case study of a small fish farm at San Martin-Peru

Arapaima gigas is an Amazon specie with great commercial demand and high production performance, but its feasibility is variable. The current study aimed to perform an economic evaluation of the production of A. gigas on earth ponds in San Martin, Peru. Three hundred young fish (19 ± 0.01 cm and 68.32 ± 0.01 g) were stocked (ten fish·m–2 in three ponds of 1000 m2 for 390 days). Growth performance was evaluated based on the survival, feed conversion rate (FCR), final mean weight, final average length, weight gain, specific growth rate, and productivity. Investment, costs, indicators, and feasibility were determined. Arapaima gigas has a profitable production performance in earth ponds in Peru, fish presented a weight gain (kg) of 11 kg in 390 days and productivity of 3,265.70 kg·ha–1. Food and fingerlings were the most important items in the production cost. This production is a low-investment and high-profitable business, with an incremental investment of US$3,287.15, profit of US$ 3,977.38·cycle–1, Net Present Value of US$ 22,149.37, and an Intern Rate Return of 32.28%. This could be a way of increasing the income of small producers through the diversification of their production.

Bioprocess for mass production and feed utilization of Azolla pinnata in aquaculture ponds: a perspective of bioeconomy and eco-friendly technology for small farms

Aquatic plants have a high potential to be used as eco-friendly technology in fish farming effluent treatment systems. However, there is still a reduced use of the vegetable biomass produced in these treatment systems. Thus, the aim of this study was to develop an alternative feed with the aquatic plant Azolla pinnata to take advantage of plant biomass, reusing the plant to develop a new product and promote a circular economy. A. pinnata was implemented in decantation pond that receives effluents from fish farming. Samples were collected weekly at four times (0, 7, 14, and 21 days). Posteriorly, A. pinnata was processed to obtain the meal. Azolla meal was offered along with three commercial feed (24%, 28% and 32% of the crude protein) in an experiment to evaluate the zootechnical performance of tilapia in small tanks. The results indicated that A. pinnata was efficient to retention of phosphorus and nitrogen after seven days. In the experiment with animals, the treatment using commercial feed with 28% of the crude protein + Azolla showed the best efficiency rates for using the diet. Thus, the use of the A. pinnata meal was a viable alternative in the search for sustainable products to promote a bioeconomy in the small fish farms.

Effect of fish downstream supply chain on wealth creation: the case of tambatinga in the Brazilian Midnorth

We describe the downstream supply and value chains originating from commercial tambatinga farming in Midnorth Brazil, which was used as a model for inland pond fish farming in tropical South America. We assessed how farm size affects intermediaries, job creation, income generation, and the number of wealth beneficiaries. We surveyed 16 commercial farms from 0.1 to 220 ha and their supply chains. To compare wealth creation and the number of beneficiaries, we established a baseline annual production of 550 t. Labor hours per tonne tended to rise in medium and extra-large farms. We identified 7 downstream supply/value chains, which can be grouped into farmer-controlled and intermediary-controlled supply/value chains. The first group includes small farms selling their fish directly to consumers, while the second encompasses medium, large, and extra-large farms relying on intermediary trading. These two types showed different impacts on wealth creation and the number of wealth beneficiaries. The first group generates significant wages concentrated in the farmers’ segment. This permits small farms to compensate for their low production level and to obtain economic outcomes sufficient to have a decent life and it allows wealth distribution. This model makes small fish farms (around 1 ha or less) an interesting business to alleviate poverty, provide food security and decent jobs, and reduce inequalities. The intermediary-controlled chains consist of non-vertically integrated farms composed of supply chains with intermediaries that transport and trade fish, mostly in remote markets. Thus, various stakeholders share the gross revenue. This was found to result in poor economic outcomes for the livelihoods of small farms and small intermediaries. Therefore, this model is more suitable for large farms or intermediaries, resulting in fewer wealth beneficiaries.

Detection of Virulence-Associated Genes and in vitro Gene Transfer From Aeromonas sp. Isolated From Aquatic Environments of Sub-himalayan West Bengal.

Aeromonas is omnipresent in aquatic environments and cause disease within a wide host range. A total of thirty-four isolates from water samples of small fish farms were identified as Aeromonas based on biochemical characteristics and 16S rRNA gene sequence. A total of six virulent factors were analyzed which indicated 100% of isolates as beta-haemolytic and proteolytic, whereas 44.1, 38.2, and 70.6% of isolates produced DNAse, siderophore, and amylase, respectively. Studies on the occurrence of four genetic determinants of virulence factors revealed that aer/haem (haemolytic toxin) and flaA (polar flagella) genes were present in 44.1% of strains whereas ascV (type 3 secretion system) and aspA (serine protease) genes were detected in 21.5 and 8.82% of strains, respectively. Fish (Anabas testudineus) challenge studies showed that the isolate GP3 (Aeromonas veronii) bearing five virulent factors with the combination of aer/haem+/ascV+/fla+ genes induced severe lesions leading to 100% of mortality. In contrast, RB7 possessing four virulence factors and three genes (aer/haem+/ascV+/aspA+) could not produce severe lesions and any mortality indicating the absence of correlation between the virulence factors, its genes, and the pathogenicity in fishes. GP3 was cytotoxic to human liver cell line (WRL-68) in trypan blue dye exclusion assay. The 431 bp aer/haem gene of GP3 was transferable to E. coli Dh5α with a conjugational efficiency of 0.394 × 10–4 transconjugants per recipient cell. The transfer was confirmed by PCR and by the presence of 23-kb plasmids in both donor and transconjugants. Therefore, the occurrence of mobile genetic elements bearing virulence-associated genes in Aeromonas indicates the need for periodic monitoring of the aquatic habitat to prevent disease outbreaks.

Technological factors in the cultivation of sterlet sturgeon planting material in a recirculation aquaculture system

Recently, it has not been possible to engage in natural reproduction of sturgeons in Dagestan, because the spawning rivers Terek and Sulak are regulated, and the passage to the spawning grounds is completely closed by dams. There is only one way out for the restoration of sturgeon stocks it is artificial reproduction through industrialization and the creation of complex, closed regulated fish farms that can function both in the form of small fish farms and in the form of large holdings. The purpose of the work was to study technological factors in the cultivation of sterlet sturgeon planting material in a recirculation aquaculture system. The object of the study was a population of sterlet sturgeon (Asirepseg ruthenus Linnaeus, 1758) – a freshwater fish species of the sturgeon family. The study material was normally pigmented and albino (colored) sterlet with an average initial weight of 60 g. Under the conditions of the Republic of Dagestan studies have been carried out to establish the influence of a complex of biotic and abiotic factors (temperature, oxygen, planting density, feed grade, meat and bone attractant, probiotic Subtilis) on the growth, morphometric indicators and survival of juvenile sterlet sturgeon in the recirculation aquaculture system. The fish-breeding and biological characteristics of pigmented and albino sterlet have been given. It has been established that the design features of the recirculation aquaculture system did not allow to meet the biological needs of sterlet in water. The flow rate of water entering fish tanks was limited to 10 l/min per 1 m³, which provided a water change in 1 hour 40 minutes at a standard of 20–60 minutes. The optimal planting density of sterlet with an initial body weight of 58–64 g under conditions of limited water supply (10 l/min/m³) was the density of 250 pcs. /m³. The effectiveness of using two formulations of compound feed when growing both normally pigmented fish and their albinos showed that the highest fish-breeding indicators were obtained in normally pigmented sterlet when feeding with Sturgeon Grower No. 4 (47/13). The economic effect amounted to 373,5 rubles/m³. In albinos, the highest fish-breeding indicators were obtained when feeding productional feed Sturgeon grower 46/18 with. The economic effect was 285,0 rubles/m³.

DEVELOPMENT OF AUXILIARY CRAFT IN THE KAZAKHS OF THE SOUTHERN REGION

The downstream of Syrdaria is an area of utmost development of fishing trade. In these territory people from ancient times used fishery as additional occupation. The increase in number of Russian set- tlers nad the construction of Orynbor-Tashkent railway in 1901-1904 years had great impact on fishing trade evolution in the area. People who know fishing, processing settled from banks of Volga, Astrakhan areas.The artice is dedicated to the study of fishing culture peculiarities of Aral fishmen. The materials are taken from the XIX and early XX century travelers, investigation expedition’s data. Moreover, the territorial peculiarities of fishing in Perovsk and Kazaliuezd, which are situated in Syrdaria downstream, is investigated. The tsarist government’s fisheries policy was primarily in the interests of the treasury. The abolition of the system of leasing and privatization of fishing grounds, as well as the issuance of permits for free fishing in the sea have created conditions for various groups of the population engaged in fish farming. Conflicts and disputes between the owners of large and small fish farms were regulated by the state through laws.The first ethnographic data about this area is written in military leaders and military travelers investigations. Although the military investigation of Kazakh territory proposed Russian power in the area the reconnaissance purpose includes basic data which can be used as the evidence of some Kazakh lifestyle peculiarities. The source of information of the article includes Berg, Butakov, Dobromislov works. Key words: fish, fishing, farming,craft, trade.

Apparent digestibility coefficients of local palm kernel cakes, rice bran, maize bran and sago flour in the GIFT strain of Nile tilapia (Oreochromis niloticus)

ABSTRACT An experiment was conducted to estimate the apparent digestibility coefficients (ADC) of macronutrients and energy of local palm kernel cakes, rice bran, maize bran and sago flour in Nile tilapia, Oreochromis niloticus (average initial body weight of 30.49 ± 0.38 g). A reference (basal) diet was formulated to contain 33% crude protein, 7% crude fat and 390 Kcal/100 g diet, all on a dry matter basis. The acid-insoluble ash was used in all the diets as the digestibility marker. The experiment lasted 37 days, including a growth phase of 28 days followed by a feces collection phase of 9 days. The results showed that the ADCs of dry matter, crude protein, crude lipid, ash, crude fiber, total carbohydrate and gross energy were 79.74%, 83.53%, 78.79%, 83.84%, 75.53%, 78.20% and 79.25% for the conventional palm kernel cake, 46.36%, 34.59%, 47.89%, 34.94%, 60.35%, 51.69% and 47.96% for refined palm kernel cake, 58.67%, 51.00%, 65.10%, 60.39%, 63.59%, 59.44% and 60.50% for rice bran, 79.24%, 94.03%, 80.34%, 99.69%, 83.83%, 76.85% and 78.61% for maize bran, and 33.74%, negative value, negative value, negative value, 8.49%, 47.65% and 35.96% for sago flour in tilapia, respectively. The present study generated original information on the digestibility of nutrients contained in these local foodstuffs, which represents a baseline, original information that could be used to formulate least-cost local feeds. However, to account for the changes in the nutrient content of these local associated with seasonality, plant variety and improvement in ingredient processing on the quality of the ingredients available on local markets, it would be interesting to collect additional samples, several times a year and run similar digestibility experiments on a regular basis, in order to have a comprehensive database that could be used by local feed miller to manufacture feed for small fish farm holders.

Hydrobiogeochemistry of Two Catchments in Brazil Under Forest Recovery in an Environmental Services Payment Program.

We investigated the fluvial geochemistry of two catchments at different stages in the forest recovery process which have been a focus of an Environmental Services Payment (ESP) program in Brazil. The Posses (PS) and Salto de Cima (SC) catchments (1200 ha and 1500 ha, respectively) are situated in the municipality of Extrema, Minas Gerais state. Their streams flow into the Jaguari River that supplies part of the water demand of the São Paulo metropolitan area. Samples were collected for chemical analysis and physical-chemical field measures every 2 weeks from January to December 2017. An important pollution point source was discovered in the PS stream related to bovine urine and feces, as well another unidentified source that can be related to a small food processing industry and/or a small fish farm. At the SC stream, on the other hand, there was clear evidence of domestic sewage input. This preliminary study confirmed a limited improvement of the stream water quality in response to recovery of the forest vegetation. Therefore, we recommend that in addition to enhanced monitoring to help distinguish biogeochemical sources and the benefits of land conservation practices, the ESP program should consider controlling point source pollution to accomplish its purpose.

Habitat characteristics of the Japanese water shrew, Chimarrogale platycephalus

Abstract To determine the habitat characteristics of the Japanese water shrew, Chimarrogale platycephalus, seven stream parameters were studied along five streams. The shrew occurred along three of those streams. To evaluate the stream parameters related to water shrew occurrence as an objective variable, a generalized linear model analysis of the five streams was performed. The results indicated that current velocity was the most important parameter in shrew occurrence at p<0.001. The present findings are similar to those for the European water shrew, Neomys fodiens. The number of invertebrates as availability of food resources, however, was not a significant parameter influencing shrew occurrence. Along the banks of the two streams inhabited by C. platycephalus, there are artificially managed leisure fishing sites, and small fish farms have released fish regularly into the streams to stock up fishing resources. Such management of leisure fishing may provide the water shrews with fish as an additional food resource and possibly contribute to the occurrence of C. platycephalus.

The emergy ecological footprint for small fish farm in China

Mariculture, especially cage aquaculture remains a growing, vibrant and important production sector for high protein food in coastal regions in China. A quantitative evaluation of the mariculture system is an essential step to documenting its’ sustainability. The method of emergy ecological footprint is applied to evaluate the environmental sustainability of an offshore small fish farm (Great Marine fish farm, GMFF) in the East China Sea. All input needed to support fish farming were accounted and converted into biological space, to estimate the natural capital demand for the rearing process in terms of global hectares. The emergy ecological footprint of GMFF was 1953.19ha, meaning that nearly 2000ha of ecologically productive lands were needed to support the fish framing. The largest component of emergy ecological footprint was forage (1183.64ha), which took up 60.60% of the total footprint; the second and third largest footprint components were fingerlings and fuel. In a word, emergy ecological footprint can serve as a practical and meaningful tool for comparing and monitoring the environmental impact of fish farming. The strong dependence of external contributions of exploiting the wild fish resources affects strongly the level of environmental sustainability of fish farming.

Impacts of fish farm pollution on ecosystem structure and function of tropical headwater streams

We investigated the impacts of effluent discharge from small flow-through fish farms on stream water characteristics, the benthic invertebrate community, whole-system nitrate uptake, and ecosystem metabolism of three tropical headwater streams in southeastern Brazil. Effluents were moderately, i.e. up to 20-fold enriched in particulate organic matter (POM) and inorganic nutrients in comparison to stream water at reference sites. Due to high dilution with stream water, effluent discharge resulted in up to 2.0-fold increases in stream water POM and up to 1.8-fold increases in inorganic nutrients only. Moderate impacts on the benthic invertebrate community were detected at one stream only. There was no consistent pattern of effluent impact on whole-stream nitrate uptake. Ecosystem metabolism, however, was clearly affected by effluent discharge. Stream reaches impacted by effluents exhibited significantly increased community respiration and primary productivity, stressing the importance of ecologically sound best management practices for small fish farms in the tropics.

Design, Development, and Testing of an Autonomous Boat to Reduce Predatory Birds on Aquaculture Ponds

A small robotic autonomous boat was designed for the purpose of protecting fish from predatory birds on aquaculture ponds. The boat is completely self-sufficient and can remain permanently on a farm pond using only solar power for energy, a microcontroller for directional control and object detection, and the shoreline for confinement area. Bird removal and consequential fish protection is provided by the continued movement and presence of the boat on the surface of the pond. Testing of the boat on a 0.4 ha pond in southern Louisiana indicated that it had a BAIR (bird area influence rate) of 0.54ha per hour. When tested for bird removal qualities on a 0.6 ha pond, results indicated that cormorants were reduced by 85% and wading birds by 70% per hour. Mechanical operation of the boat was good, with only two minor breakdowns during a one-month period of continuous use, but more solar power is desired to increase the working time of the boat during late fall and winter periods. This alternative approach to bird scaring is capable of environmentally friendly reduction of predatory birds on small fish farm ponds and has been proven to be mechanically feasible for aquaculture ponds of 1 ha or less. It may be useful on minnow ponds and other larger bodies of water with proper redesign, scaling, and deployment of the boats.

Fish Health Management in Slovenia

Slovenian aquaculture system is quite specific because we have small water sources and small fish farm facilities, which is reflected also in the organisation of fish health management. In fish health management we pay close attention to the prevention of fish diseases. The technology of fish farming, fish handling and nutrition are controlled both, from the economic and fish welfare point of view. Brown trout, marble trout, lake trout, brook trout, huchen, grayling, common carp, nase and chub are bred for restocking. Besides fish production for restocking, rainbow trout and common carp are produced for human consumption. In the last 15 years the number of fish farms has considerably increased. In compliance with the National Programme financed by the Veterinary Administration of Slovenia of the Ministry for Agriculture, Food and Forestry, all hatcheries have to be examined to IHN and VHS viruses, all carp for restocking have to be examined to spring viraemia of carps and eritrodermatis. In Slovenia, whirling disease is also a notifiable disease and all trout fingerlings have to be examined on Myxobolus cerebralis. Other fish farms are examined according to the epizootiological situation or with regard to clinical and pathoanatomical changes presumptive of notifiable diseases.

Utilization of the filter feeder polychaete Sabella

The filter feeder sabellid Sabella spallanzanii Gmelin (Polychaeta, Sabellidae) was proposed as biofilter in the treatment of wastes from intensive aquaculture. The species was previously studied concerning reproductive traits and ecological requirements; moreover, previous laboratory experiments indicated a positive action of its feeding activity on solid removal from water column coupled with an interesting microbiological activity. In the present paper data on settlement and growth rate from a natural population, together with data on the bioremediation activity of an adult population, relative to an experiment conducted in a small fish farm are reported. Results seem to encourage further studies on S. spallanzanii for a future utilization in bioremediation of fish farms with recycled water. Data from natural annual settlement indicated, however, the unreliability in obtaining settlers from natural populations, so that the artificial reproduction of the target species will be one of the main points of further investigations.

Underground waters in Kamnik and Savinja Alps

Dye-tracing tests in the region of the alps Velika planina and Mala planina have shown that the major part of the region drains towards the spring of the Lučnica at Podvolovljek where is also a small fish farm. As to the water level, the marginal and central parts also drain into the stream Lučka Bela or the springs at Volovljek. Quite interesting is the high-mountain plateau Veža, a karstified territory surrounded by the valleys Robanov kot and Podvolovljek, as well as the tributary area of the stream Kamniška Bistrica. Here there is every indication of the deep runoff into the springs above Luče, the spring Pečovski izvir, the temporary springs which are close to the stream Savinja and into the unknown springs in the gorge below the rocky needle Igla. With regard to the water level, the higher parts of the massif can drain towards the valleys Robanov kot, Podvolovljek and Kamniška Bistrica. The tributary area of the Bistrica is quite well known, too. It has been discovered that the area of the saddle Kamniško sedlo drains tovvards the springs of the Savinja. The territories of the saddle Kokrsko sedlo, the alps Dolge njive and Kalce drain into the spring Studenci below Mokrica.