Pen Culture Research Articles

Socio-Economic Profile and Vulnerabilities Assessment in Small-Scale Fisheries of Lower Gangetic Flood Plain Wetland: An Initiative Towards Achieving Wetland Ecosystem Sustainability and Community Well-Being

ICAR-CIFRI has been continuously working to develop wetland fisheries in a transdisciplinary knowledge-to-action mode to upscale the livelihood of vulnerable small-scale fishermen communities. The integrated development approach was initiated in different lower Gangetic floodplain wetlands of North 24 Parganas, West Bengal, India, to increase the fish production and socio-economic development of small-scale fishermen communities of the wetlands. Duma is one of the most extensive horseshoe-shaped wetlands in Asia. To augment the fish production from this wetland, the pen culture system was adopted by the fishers under the supervision of ICAR-CIFRI in 2021. Within a year, they received 15 tons of commercial fish, valued at around 30 lakhs apart from the small indigenous fish. It has recently been advised that auto-stocked, high-value minor carp in the wetland be adopted to improve income and conserve small indigenous species. In this article, SDG 14 (Life below water) addresses sustainable ecosystem management and livelihood enhancement for the wellbeing of the local people (SDG 3). Nutritional security of the local people is maintained through the small indigenous fish species which is crucial for addressing ‘No hunger’ as per SDG-2. The research also proves that women can play a crucial role in small-scale fisheries and they can economically stand alone, which is the main aim of SDG-5 (gender equality). However, significant issues such as lack of jurisdictional coordination, ecological changes, inequitable distribution of benefits, and income reduction persist in wetland management. The need for urgent reformation of policy and resource management systems is crucial to boost the economic efficiency of the SSF in the wetland. Training for more knowledge on fishing and fish farming, acquiring alternative livelihood and education on financial management should be brought to the fishermen’s communities. These could develop a resilient community that is more equipped to respond to future crises.

Development of gadgets and systems in plastic for use in freshwater aquaculture

The usage of plastics has transformed the agricultural production sector and has great impactin improving the overall scenario in all production systems including fisheries and aquaculture.Nylon fishnets, components of RAS, aquaponics and biofloc (BF)systems, plastic pipe framed nylon net cages, pen culture in water locked areas, etc. are some of the important uses of plastics in aquaculture. The AICRP on PEASEM, ICAR-CIFA, Bhubaneswar Centre is working since its inception in 1988 and contributed several plasticulture technologies and products for the development of aquaculture systems and processes (APA/CIFA 1988-2005; Mohapatra et.al., 2003, 2011 and 2016). The design and fabrication of the plastic gadgets and systems have been done considering the biological requirements of the aquaculture. The developed technologies are fully or partially adopted and accepted by the farming communities of the country. The paper presents some of the developed gadgets and systems that are presently in use in aquaculture in the country. Those are portable FRP carp hatchery having capacity of 1.0-1.2 million spawn production per cycle; portable FRP magur hatchery for incubation of 50,000 eggs per cycle; portable FRP pabda hatchery for production of 25,000-30,000 early fry per operation; different types of fixed and floating cages; live fish transportation tank of 1200l capacity which can be transported in a jeep trailer, power trailer or trolley; FRP silos of different sizes for fish rearing; feeders of different types such as demand, semiautomatic and automatic for fish feeding; plastic covered ponds for raising fishes in winter season; floating nursery for fish seed and aquaponics.. KEYWORDS :Modern farming Technique, Gedgets Plastic, Aquaculture

Differences in Waterbird Communities between Years Indicate the Positive Effects of Pen Culture Removal in Caizi Lake, a Typical Yangtze-Connected Lake

Considering the negative effects of wetland degradation, various measures have been implemented to restore wetland habitats for aquatic organisms, and their effectiveness levels must be assessed. To reduce the effects of aquaculture on aquatic communities, pen culture facilities, which are widely distributed in Yangtze-connected lakes, were removed in 2018. We surveyed and compared waterbird communities in Caizi Lake during the four months before (2017–2018) and after net pen removal (2021–2022) to evaluate their effect on the diversity and species composition of wintering waterbirds. After net pen removal, the richness and number of individual waterbird species increased, whereas the Shannon–Wiener diversity index did not change because the increase in the bird number throughout the year was mostly associated with a few species. The response of individual numbers of different guilds to the removal of net pens differed. The number of deep-water fish eaters, seed eaters, and tuber feeders increased, whereas that of invertebrate eaters decreased. The species composition also changed, particularly in the northeastern and southwestern parts of the lake. Differences in waterbird communities between the winters of 2017–2018 and 2021–2022 indicated that net pen removal had a positive impact on waterbird communities.

Ecosystem-based fishery enhancement through pen culture of Indian major carp Labeo catla in a tropical floodplain wetland of North Eastern Region, India, during COVID pandemic.

The present study was conducted with the objective of developing ecologically and economically feasible pen culture protocols for Labeo catla as an alternate income source for wetland fishers in the context of the COVID-19 pandemic. Yearlings of L. catla (12.33 ± 1.99 cm mean total length and 26.05 ± 6.57 g mean weight) were reared in HDPE pens (500 m2 area each) at three different stocking densities of 3 (SD3), 6 (SD6) and 9 (SD9) no. m-2 in triplicates. Fishes were fed with floating pelleted feed containing 28% crude protein and 5% crude lipid two times daily at 1.5-3% of body weight. During the culture period, fish grew from 26.05 ± 6.57 to 434.61 ± 30.63 g, 306.13 ± 10.68 g and 221.13 ± 14.92 g, respectively, at stocking densities of 3, 6 and 9 no. m-2 respectively. Weight gain percentage and specific growth rate declined with increase in stocking density. Gross fish yield increased with increase in stocking density and was highest at SD9 (657.92 ± 53.55 kg pen-1), while net fish yield increased initially from SD3 to SD6 (594.31 ± 29.72 kg pen-1) and then declined with further increase in stocking density. Important water quality parameters influencing fish growth were measured, and significant difference (p > 0.05) was not observed between treatments (inside pens) and reference site (outside pen at 10-m distance). Weight gain was positively correlated (p < 0.05) to water temperature (r = 0.989) and total phosphorus (r = 0.81). Benefit cost ratio and net return was highest at SD3 (1.61; US $518.88, respectively). Stocking density of 3 no. m-2 can be considered economically feasible for table fish production of L. catla in pens. Post pen culture, monthly income of fishers increased by 10.76-179.11%, with a mean increase of 90.57%, compared to the period of first COVID-19 wave in India. The present findings can provide an impetus for effective utilization of pen enclosures for income generation and livelihood enhancement of small-scale wetland fishers during pandemic.

The Success of Freshwater Aquaculture Program: Nile Tilapia or “Nila” Culture In Indonesia

This paper discusses the current status of tilapia aquaculture production, historical development based on the production growth, technological advances in genetic improvement and culture system, trade and product development, strategies, and policies in maintaining and improving national production. All data and information used in this manuscript were collected from available publications relating to the past and present status of tilapia cultivation in the country. Nowadays, Indonesia is the second-largest tilapia producer in the world with the contribution of about 25.89% to tilapia global production. In Indonesia, tilapia is the largest production among other cultured species. The annual growth production of tilapia is inccread 11.61% from 2011 to 2018. West Java Provinceis the largest tilapia producer followed by West Sumatra, South Sumatra, and Central Java. In the last six years, most of tilapia production comes from pond culture followed by floating cages, net cages, paddy fields, and pen culture. The success of tilapia culture is much influenced by technological improve in grow-out and genetic improvement of the local varieties. A side of that, trading and global market oriented are also established with various acceptable products. Tilapia aquaculture in Indonesia shows the succsess story of freshwater aquaculture program from nothing before 1990 to be something at present time. To maintain and increase the future production of tilapia, it needs strategies and policies in production and trade. The tilapia program maybe used as a role model for another economic imprortant freshwater species in Indonesia.

Socioeconomic Status of Cage, Pen and Pond Culture Freshwater Fish Farmers in Seraikela Kharswan District, Jharkhand

The study was investigated to assess the livelihood of fishermen from different fish production system in Seraikela Kharswan district. It focused on the age, community, education level, family size, farming experience, source of credit etc. In cage and pen culture system the maximum percentage of people fall in the age group of 30-39 with 34.72 and 43.05 percentage. Out of the four selected communities, OBC is the predominant among them. The result of the study revealed that 19.44 percent of illiterate respondent comes under pond culture. Cage culture and pen culture has recently introduced in inland sector in India therefore in terms of experience both category respondents have less experience. In pen culture 90.28 percent of people have only 1-4 years of experience category whereas in case of pond culture 56.94 percentage of respondents have experience above 10 years. Newer technology comes with more active respondents therefore Cage culture and pen culture respondents were 81.94 and 72.22 percentage while the percentage was only 43.06 percentage in case of pond culture.

Surgical Marking Pen Contamination: Writing a Postoperative Infection Into Your Preoperative Plan.

Introduction Preoperative marking is an essential safety practice to prevent "never" events, including wrong site surgery. Moreover, the Joint Commission regulations of the Universal Protocol require that patients be marked to indicate the operative site. Marking typically occurs with a pen or marker, which may be disposable or reusable. Previous studies have demonstrated that methicillin-resistant Staphylococcus aureus (MRSA) can survive in the dark, moist, capped environment of the marking pen and thus could plausibly be a nidus for transmission from patient to patient. The Joint Commission has established no increased risk of postoperative infection with these markings. With this study, we aimed to determine the colonization of surgical marking pens in the plastic surgery population. Methods Two marking pens from five different attending plastic surgeons at a single institution were cultured in standard fashion for aerobic and anaerobic growth. All pens were used repeatedly in office settings for performing patient markings. Those same ten marking pens were then used to mark incision sites on mock patients. Standard povidone-iodine prepping was then performed in a paint-only fashion over the skin markings, and cultures were again taken. A control group consisted of cultures from five sterile pens from the operating room. Each sterile pen was opened, uncapped, and then swabbed. All twenty-five cultures were analyzed in the hospital laboratory in a blinded fashion. Results The five control pens revealed no bacterial growth. Of the 10 direct pen cultures, two samples grew coagulase-negative staphylococci and one culture contained Pseudomonas aeruginosa. The 10-patient marked and prepped specimens showed eight negative cultures and two with coagulase-negative staphylococci. Although Pseudomonas was detected on standard pen culture, no pseudomonal growth was present in any of the samples after patient marking and prepping with povidone-iodine. Conclusions Our findings reaffirm that marking pens may be vehicles for bacterial transmission and expand upon previous studies by describing the presence of bacterial colonization on marking pens even after surgical site preparation with povidone-iodine.

Standardizing Pen Culture of Small Indigenous Fish Labeo bata in the Tropical Floodplain Wetland of the North Eastern Region, India: A Step towards Sustainable Fisheries Management

Labeo bata fry were reared in high-density polyethylene (HDPE) pens at different stocking densities to determine growth, survival, feed utilization efficiency and economics in Borkona beel, Barpeta, Assam. Pens (500 m2 each) were stocked with fry at four stocking densities, 3 (SD3), 5 (SD5), 7 (SD7) and 9 (SD9) no. m−2 in triplicates. Feeding was performed twice a day at a rate of 3–5% body weight with floating pelleted feed containing 28% crude protein. Fish grew from 2.38 ± 0.30 g to 82.78 ± 3.18, 75.94 ± 0.89, 71.94 ± 0.89 and 61.81 ± 3.35 g at stocking densities of 3, 5, 7 and 9 no. m−2, respectively. Weight gain per cent ranged from 2491.85 ± 140.56 to 3371.33 ± 133.16 and specific growth rate from 1.41 ± 0.02 to 1.55 ± 0.02, both of which decreased with increasing stocking density. The net and gross yields increased with increasing stocking density and were highest at SD9. The benefit-cost ratio was maximum at SD7 (1.42), followed by SD9 (1.41). Post-pen culture, the monthly income of fishers increased by 6.10% (SD3) to 40.50% (SD9). Significant differences (p &gt; 0.05) in water quality parameters were not observed between treatments (inside pens) and reference site (outside pen at 10 m distance). Weight gain exhibited a significant positive correlation with temperature (r = 0.92; p = 0.029) and alkalinity (r = 0.95; p = 0.014). The present study can provide impetus towards species diversification in pen enclosures, income enhancement of small-scale wetland fishers and sustainable ecosystem-based floodplain wetland fisheries management.

Environment-friendly floating net cage culture research in Indonesia

Reservoirs and lakes are widely used for fisheries, both capture fisheries and aquaculture. Aquaculture fisheries that develop in reservoirs or lakes include floating net cages culture (FCC) and pen culture. Besides impacting the economy and employment opportunities, aquaculture activities through FCC can decrease water quality from uneaten feed and fish metabolism residue. For this reason, an environmentally friendly FCC is needed to reduce aquaculture waste. This paper reviews the development of ecologically friendly FCC research in Indonesia. Several studies on environmentally friendly FCC include double net FCC, bio-cages, carpel FCC, windowed, and triple layer FCC. Double net FCC still allows the remaining uneaten feed and feces to settle. Bio-cage research is in the innovation model stage and has no prototype or laboratory tests. Windowed FCC, made with a closed system and a few gaps for circulation, can accommodate aquaculture waste and not spread into the waters, but fish grow slower than other FCC. The loop bio-phytoremediation of FCC or Smart FCC has three layers that can accommodate waste, and the waste will be used for plants that function as filters and phytoremediators of waste. Smart FCC is an aquaponic system modified to be applied in reservoirs/lakes.

A remote sensing approach to explore the available water spread for fisheries development in the reservoirs of Godavari River Basin, Telangana, India

Reservoirs have tremendous fisheries potential amongst the inland water resources and aptly referred as ‘sleeping giants’, as the fish yield potential of these resources are yet to be tapped. Existing gaps in the availability of absolute information and data on the inland water resources hinder the applicability and implementation of various fisheries development programmes, which in turn impact inland fisheries production. The present study was carried out in the reservoirs viz., Sri Ram Sagar, Kaddam and Swarna from the Godavari Basin, covering the period 2016-2021, as a case study to demonstrate the use of remote sensed data in fisheries stock enhancement planning. The perennial and seasonal water spread area of the reservoirs under study, estimated through composite water maps prepared using Sentinel 2A data ranged between 8 to 19 and 4 to 29%, respectively. Further, the potential area for enclosure fish culture (both cage and pen culture) in these reservoirs were found to range between 14.89% (Sir Ram Sagar) to 48.54% (Kaddam). The field validated results revealed less than 0.1% of the perennial water spread area mapped in these reservoirs is under use for cage culture. This highlights under-utilisation of these reservoirs and demonstrates scope for developing enclosure fish culture or other culture-based fisheries for enhancing the fish production. The study also demonstrates the use of geospatial tools in development planning for expanding enclosure fish culture in the reservoirs and in turn enhancing fisheries production from the reservoirs in India. Keywords: Composite water maps, Enclosure fish culture, Geospatial tools, Godavari River, NDWI, Reservoir, Sentinel 2A data, Water spread area

Changes in Fish Assemblage Structure after Pen Culture Removal in Gehu Lake, China

The removal of the net enclosure has been used as a lake management strategy in various regions of China as ecological development is given more attention. Nevertheless, little is known about the substantive impact of this measure on fish communities in inland lakes. To this end, the fish community composition and structural features after the removal of the net enclosure in Gehu Lake were explored and evaluated in this study from 2021 to 2022 and compared to the investigation before the net enclosure removal from 2017 to 2018. Belonging to 7 orders, 10 families, and 46 species, a total of 17,151 fish were collected, with pelagic, sedentary, and omnivorous species dominating. In comparison, the number of species increased by 10 after removal, and fish alpha diversity increased. The Index of Relative Importance (IRI) revealed that the composition of dominating species remained constant, including Coilia nasus, Hypophthalmichthys molitrix, and Hypophthalmichthys nobilis; Parabramis pekinensis, Megalobrama amblycephal, and Culter mongolicus were upgraded from common species to general species. Culter alburnus, Hemiculter bleekeri, and Pseudobrama simoni were downgraded from general species to common species. Elopichthys bambusa had become a common species (IRI = 109.35), which was not discovered before removal. According to the hierarchical clustering (HC) and non-metric multidimensional sequencing (NMDS), the fish community of the northern reserve was highly aggregated. As the Abundance Biomass Comparison (ABC) curve and biodiversity index indicated, the fish community structure of the whole lake was in a state of moderate anthropogenic disturbance with reduced stability, while that of the northern reserve was in a state of light anthropogenic disturbance with greater stability. The number of fish species increased in this survey compared to the period before removal, species and dominant species composition altered dramatically, and total lake stability declined. This study demonstrates that the fish diversity in Gehu Lake increased after the removal of the net enclosure. Meanwhile, the stability of the fish community structure was decreased temporarily. Lake restoration is a long-term process, and the underlying impact of the removal of the net enclosure still requires continuous monitoring and further studies.

Integration of pen aquaculture into ecosystem-based enhancement of small-scale fisheries in a macrophyte dominated floodplain wetland of India.

The rapid degradation, overexploitation, and encroachment of floodplain wetlands have led to considerable decline in fish diversity and production from these invaluable aquatic resources threatening livelihood of the dependent fishers. The climate change evident in the fast few decades has further aggravated the problem of eutrophication causing water stress and sedimentation leading to rampant macrophyte proliferation affecting ecological and economic functioning of these ecosystems. Macrophyte control and management needs serious attention for sustaining ecosystem services provided by these resources. In this direction, pen culture of grass carp Ctenopharyngodon idella as a biocontrol for macrophytes along with Indian major carps was implemented in a co-management mode in Beledanga, a typical floodplain wetland, a gradually shrinking, macrophyte dominated floodplain wetland in lower Ganga basin. Indian major carps Labeo catla (6.28±0.23g), Labeo rohita (5.1±0.12g), Cirrhinus mrigala (3.5±0.08g) were stocked in the ratio 4:3:3 at the rate of 20 Nos.m-2 in pens (0.1ha each) in triplicate. Grass carp (7.1±0.42g) was stocked in pen at the rate of 20Nos.m-2 in duplicate. The fishes were fed with pelleted feed twice a day at the rate of 2-3% of body weight. The seed was overwintered in pens for a period of 90 days from November 2019 to January 2020. Average weight recorded at the end of culture period was 25.13±1.70g, 18.11±0.63g, 14.53±0.87g, and 39.20±1.90g in L. catla, L. rohita, C. mrigala, and C. idella, respectively. The survival of fish ranged from 70 to 81%. Growth performance and feed utilization efficiency of grass carp were significantly higher (p<0.05) compared to other carp species. The pen culture was found to be economically viable with a benefit cost ratio of 1.53. The fishes produced were released back into the open wetland as an additional input for culture-based fisheries. The intervention along with niche-based enhanced stocking led to 24% increase in the fish production from the wetland with grass carp contributing 20-22% of the total catch with 32% increase in revenue generated by the sale of fish within a short span of 1 year. The study successfully demonstrated technological suitability and economic feasibility of pen culture in this wetland and role of grass carp as a potential biocontrol species for macrophyte management. Grass carp stocked in open wetland grew to 0.8 to 1kg within 6 months and 2-2.3kg within a year and could utilize 40-45% of the submerged and emergent macrophytes. Integration and optimization of grass carp will not only aid in habitat management of macrophyte-choked wetlands but will also boost their small-scale fisheries by converting standing macrophyte biomass into protein-rich fish biomass. The enhanced production will also cater to nutritional and livelihood security of the dependent fishers.

Application of compost in the different of pen culture substrates type for the intensification of sea cucumber, Holothuria scabra (Jaeger 1883) culture

Intensification of aquaculture is directed at the effort to increase productivity by carrying capacity of production factors. This study was conducted to evaluate the growth performance of Holothuria scabra cultured intensively through the application of compost fertilizer. H. scabra were reared for 90 days (20 individuals/m2 of density), using a pen culture method on the three different substrates, namely fine sand, seagrass mud, and coarse sand, where each treatment was made as four replicates. The amount of compost used for the type of each substrate was the same. The results showed that applying compost in sea cucumbers culture using the pen culture method was proven to be effective in increasing the growth performance of sea cucumbers H. scabra, with the weight gain, growth rate, and survival, respectively, ie: 49.10±1.62 g; 1.26±0.03% g/day and 90.00% on seagrass mud substrate; 46.00±6.92 g; 1.23±0.11% g/day and 89.00% on a fine sand substrate and the lowest is 42.05±g; 1.13±0.08% g/day and 87.50% were found on a coarse sand substrate. The growth response was not significantly different between the three substrate types (Duncan’s test, p>0.05), indicating that the availability of nutrient sources in substrates is one of the key factors for the intensification of H. scabra culture.

Technology, Gender and Fishing in an Odisha Village

The introduction of a new fishing technology in a small riverine village of Odisha resulted in paradoxical socio-economic outcomes. The fresh and flowing water pisciculture through the innovative Pen technology, which was based on an enclosure aquaculture system, bound from all sides by a close-knit row of multiple pens, improved productivity, income and employment levels of the fishing community. But the new technology also aggravated extant gender inequalities in the village, located on the banks of the river Mahanadi. The gendering of access to, control over and use of Pen culture in the fishing village of Naraj decided the winners and losers in this technological change. Systematic social closure and institutional bias not only ensured the exclusion of fisherwomen from accessing and utilising the new productive technology and related resources in Naraj but also reinforced the traditional male domination in the fishery sector.

Heavy Metal Pollution Reduced the Potentiality of Pen Culture in the Wetland Aquaculture in an Urban Area of Bangladesh

The Belai beel serves as an important aquatic resource for the livelihood of the local community of the Gazipur district in Bangladesh. However, water pollution in recent times, mainly from industrial wastes and sewage effluents, may disrupt its aquatic environment. Thus, the purpose of the present study was to assess the potential area of pen fish culture in the Belai beel. The study was performed in the Rajbagan (L1), Kamaria (L2) and Rewla (L3) areas of the Belai beel. Grass carp, silver carp, common carp, catla and rui of 20–30 cm in size were stocked at a rate of 15,000 fish/ha and reared for 150 days in pens installed in the L1, L2 and L3 areas, respectively. The fishes were fed with mustard oil cake and rice bran. Maximum fish production was found in Rewla (12.97 ton/ha/150 days) compared to Rajbagan (8.85 ton/ha/150 days) and Kamaria (10.67 ton/ha/150 days) due to it having comparatively good quality water. There were significant differences in metal ion concentrations (p &lt; 0.05) among the three fish pens. In the Rajbagan area, concentrations of Cd and Cu in the water coming from the industrial effluent canal exceeded the acceptable limit. Results indicated that the Rewla area was better than Rajbagan and Kamaria due to it having relatively good quality water for pen fish culture.

AN IN-DEPTH ANALYSIS OF APPLYING THE CLUSTERING TOOLS AND TECHNIQUES IN THE REQUIRED CLASSIFICATION OF PATIENT RECORDS

A huge load of programming's motorizing a couple of endeavours is coming experience every day. A collection of improvements has been peeping out in basically every region that we observer every single day. In the field of clinical office, a huge load of particular redesigns has been brought directly into it as meds yet not in keep up getting records. Consider a common patient's life who goes through meds in ordinary stretches and trusts that the actual results will be out notwithstanding a having a hard day by treating such endless individuals in facilities, an expert requirement to sort out some way to check the results and present the report back on time. Suppose the patient incorporates more in a crisis centre. In that case, the endorsement collaboration will form a genuine perspective that eats up extra time, which winds up being monstrous trouble. As of now, if an item that could automate the resulting collaboration turns into a basic factor, it gets two critical differences, that is, the patient need not believe that the results will be out for a long reach, and the expert need not sort out some way to check and explain the results. Moreover, it will similarly break the tendency of being deficient, and the patient will be allowed with the results for what they had in their body. This objective is making a digitalized stage to convey the clinical reports and private to the patients, inciting the completion of paper pen culture for results. Consequently, a lot of time spent on check and result explanation can be slashed down, which in the end saves a copious proportion of the time.

Assessment of eutrophication and nitrogen and phosphorus carrying capacity before and after removing pen culture (2013-2018) in Lake Changhu, China.

In this study, the eutrophication levels and nitrogen and phosphorus carrying capacities of Lake Changhu in Jingzhou, Hubei Province, China, were measured using the trophic level index (TLI) and Dillon model for the first time. The measurements were taken before (2013 and 2015) and after (2017 and 2018) the removal of pen aquaculture from the lake. The lake was divided into three districts: Lake Haizihu, Mahongtai Channel, and Lake Dahu. The results showed total nitrogen (TN), chemical oxygen demand (COD), chlorophyll a (Chl-a), and total suspended solid values were significantly higher in 2017 than in the other years. The Lake Haizihu district was predicted to be more seriously polluted than the other districts. In the sediment, the organic matter, STN (TN in sediment) and STP (TP in sediment) contents increased from 2013 to 2018. The mean TLI values ranged from 62.99 to 78.93 in the studied years, and the eutrophication level was highest in 2017. According to the Dillon model, when the target water quality was level III (GB 3838-2002, Ministry of Environmental Protection of China, 2002), the remaining TN and TP loading capacities were -1470.72 t/a and -182.74 t/a, respectively, in 2015, and 320.03 t/a and -111.14 t/a, respectively, in 2018. Our results provide valuable and integrated information about the water conditions of Lake Changhu, thus laying a foundation for the theoretical study of water eutrophication process in lakes and paving the way for informed decision-making for managing water environments to ensure the safety of ecology.

Enhancing adaptive capacity of wetland fishers through pen culture in the face of changing climate: A study from a tropical wetland, India

Abstract Wetlands are among the most productive of all aquatic ecosystems. In developing countries, millions of marginal fishers rely solely on wetlands for security of both nutrition and livelihood. The decline in wetland fisheries owing to anthropogenic and climatic changes has made fishers increasingly vulnerable. Pen culture can be an effective climate-resilient technology for enhancing fish production in shallow, macrophyte-choked, and multi-stake floodplain wetlands, especially in eastern and north-eastern India. In this context, pen culture was implemented as an adaptive measure in a tropical Gangetic wetland (Mathura) to enhance fish production and increase the adaptive capacity of fishers. Indian Major Carps, Gibelion catla, Labeo rohita, and Cirrhinus mrigala of initial size 10.4±.21g, 8.2 ± 0.48g, and 6.5 ± 0.23g respectively, were stocked at the ratio of 4:4:2 and at the rate of 30 fish m-2 each in pens of 100 m2 in duplicate. For purposes of conservation, Labeo bata and Gudusia chapra, 4.3 ± 0.18g and 3.8±.34g initial size, respectively, were stocked at the rate of 20 Nos.m-2 each at the ratio of 1:1. The fish were fed with commercial feed at the rate of 4% of body weight. A net survival of 82%, 87%, and 75% was recorded in Indian Major Carps, L. bata and G. chapra. A production of 380 kg IMC was achieved during 120 days of the culture period. L. bata achieved an average weight of 21.40 ± 0.34g during the 90-day culture period, with a survival rate of 87%. G. chapra attained an average weight of 16.5 ± 0.42g during the culture period, with a recorded survival rate of 75%. G. chapra was observed to spawn in the pen. The water quality inside pens and reference sites did not differ significantly (p &amp;gt;0.05). The produced fish were released in the wetland for fisheries enhancement. The present communication discusses the technological suitability and economic feasibility of adopting climate-resilient pen culture as an adaptation measure for enhancing the adaptive capacity of wetland fishers in the face of a changing climate.

Ecosystem vulnerability of floodplain wetlands of the Lower Brahmaputra Valley to climatic and anthropogenic factors

Abstract This study assessed the vulnerability of 16 floodplain wetlands (beels) of the Lower Brahmaputra Valley, Assam, India, in relation to a range of natural and anthropogenic factors including climate change. The total water-spread area of the selected beels varied widely (8–50 ha), with 68.75% of the beels showing a reduction in water-spread area over the past 30 years. High levels of siltation and encroachment and detachment of marginal areas through the construction of roads were the major factors responsible for the reduction in the water-spread area of the beels. The reduction was observed to be in the range of over 33% in three beels (Raghunath Sora, Chulkani, and Dudua beel) to 83% in Bhoishpuri beel. In addition, one beel (Chulkani) experienced reduction in its deep pool area, which is an important wetland area that provides shelter to brood fishes during the dry season. Only 12.5% of the beels studied practiced enclosure (pen) culture for rearing fish. None practiced cage culture. Our study showed that only two beels (Bhoishpuri and Tariachora) were free from exotic fishes; the remaining surveyed beels reported exotic species such as, Cyprinus carpio (Common Carp), Ctenopharyngodon idella (Grass Carp), Hypophthalmichthys molitrix (Silver Carp), H. nobilis (Bighead Carp) and Piaractus brachypomus (Pacu). The prevalence of exotic fishes in the majority of the beels (due both to escape from nearby aquaculture ponds during floods and intentional stocking in certain beels) would have adversely affected the diversity of indigenous fishes in those wetlands. From discussion with the fishers, 50% of the beels surveyed experienced a reduction in the number of fish species from that recorded 10–20 years ago. In addition to climate change-related factors (e.g. abnormal rains, floods, or drought-like situations), other factors – both natural (e.g. hyper-nutrification) and anthropogenic (e.g. construction of roads, houses, and other structures) – also adversely affected the studied wetlands. To help cope with these factors and increase the adaptive capacity of fishers, four measures aimed at mitigation are suggested. These are: the practice of enclosure aquaculture in beels; the construction of floating macrophyte refuges (katal); deep pool refuges; and stock enhancement programmes with climate-resilient indigenous fishes.

Fisheries resources of Bangladesh: A review

Fisheries sector plays a significant role in national food security, empowerment and foreign exchange earnings in the national economy of Bangladesh. At the same time, Bangladesh is blessed with enormous water resources of inland culture (8,21,923 ha), inland capture (38,90,282 ha) and marine (1,18,81,300 ha), having great potentials of fisheries production. Inland culture, inland capture and marine fisheries provides 56.76%, 28.19% and 15.05% fisheries production, respectively. The aim of this review paper is to provide a comprehensive overview on fisheries resources of Bangladesh, those are underutilized and/or need emphasis to enhance more fish production. Recently, inland culture fisheries production has increased rapidly due to adoption of improved farming practices by the farmers. However, inland capture and marine fisheries production has not yet been attained to its optimum level due to over exploitation, fish habitat degradation, siltation of water bodies and water pollution. Therefore, to increase inland capture fisheries production and conserve biodiversity, various approaches such as community-based fisheries management, beel nurseries, stocking fingerlings of endangered species, establishment of fish sanctuaries, cage and pen culture systems can be adopted. Additionally, existing banning rules and regulations of catching fish during breeding season from inland capture water bodies like rivers, haors, baors, beels etc. should be implemented properly for conserving biodiversity and increasing fish production, as banning of 22-days in rivers and 65-days in marine water have significantly increased hilsha fish production. In addition, blue economy has recently gained impressive attention in Bangladesh due to getting huge marine water resources from Myanmer in 2012 and India in 2014. Therefore, marine aquaculture systems for example farming of seaweed, sea bass, mullets, promfrets, mud crab etc. should be adopted for achieving the United Nations agenda on sustainable development goal 14 on conservation, sustainability and use of oceans, seas and marine resources for increasing economic benefits.