Fish Weight Research Articles

Biofloc based farming of Nile tilapia (Oreochromis niloticus) in tanks under different stocking densities

This experiment was conducted to optimize the stocking density of Nile tilapia (Oreochromis niloticus) in biofloc based farming system in tanks for a period of 90 days from 23 December to 22 March 2022 in Mohanpur upazilla, Rajshahi district, Bangladesh. The experiment was conducted in 5000 L cemented tanks (5m3) under three different of stocking densities (T1: 200 fishes/m3, T2: 150 fishes/m3 and T3: 100 fishes/m3) having three replicates each. The initial weight of fish was 11.50±0.35 g and fishes were fed (34% protein content) twice a day @ 5-3 % body weight. Among three treatments, a significantly higher (P<0.05) average daily gain (ADG) of 1.15±0.07 g with specific growth rate (SGR) of 2.44±0.09 % day-1 were recorded in T3 treatment but a significantly higher (P<0.05) average yield of 118907.70 and 114914.20 kg/ha/3 months were obtained in T1 and T2 treatment, respectively. Higher average net benefit of 1231671.90 BDT/ha/3 months and BCR of 0.12 were obtained in T2 treatment which is significantly higher (p<0.05) than T1 and T3 treatment. By an economical assessment, if the sales price is influenced by the final body weight, the reduced average harvest weight in higher stocking densities could lead to low profitability. Therefore, it is concluded that the use of intermediate stocking density, around 150 fishes/m3, has higher profitability since it produces a large proportion of harvested fish that reach high body weights, and possible high selling prices, combined with desirable biomass.

Prevalence of Lernaea cyprinacea Infections in Indian Major Carp at Fish Farms of Bihar, India

Lernaea cyprinacea, commonly known as anchor worms, represents a significant parasitic threat to Indian Major Carp (IMC) species in the aquaculture system. Lernaea parasitizing is widely reported, affecting brood stock, fingerlings, and marketable-sized freshwater fish species globally. This study aims to comprehensively investigate Lernaea infections in ten fish farms across Bihar, India, focusing on the prevalence, intensity, water quality parameters, fish weight, and associated factors affecting the occurrence of this parasite. The research combines field surveys, laboratory analysis, and epidemiological assessments to provide a holistic understanding of the impact of Lernaea on the health and productivity of Indian major carp populations. The analysis revealed a positive correlation between host body weight and the intensity of Lernaea cyprinacea infestation. Larger fish were more susceptible to parasitic infections, highlighting a potential vulnerability associated with the size of the host. In conclusion, this study contributes valuable insights into the dynamics of Lernaea cyprinacea infections in IMC stocks, emphasizing the species-specific susceptibility and the influence of host body weight on parasitic infestations. The findings provide a foundation for informed aquaculture practices aimed at minimizing the prevalence and impact of Lernaea, thereby enhancing the overall health and productivity of fish farms in the region. In conclusion, current research confirms that Labeo catla and larger fish are very susceptible to Lernaea cyprinacea infection.

Black Soldier Fly Larvae Meal vs. Soy Protein Concentrate Meal: A Comparative Digestibility Study in Barramundi (Lates calcarifer)

Black soldier fly larvae meal (BSFM) from Hermetia illucens has emerged as a dependable protein source in aquaculture. This study aimed to assess BSFM’s digestibility in barramundi juveniles and compare it to soy protein concentrate meal (SPCM). Four diets (control, 30% BSFM; 30% SPCM; and commercial feed control) were tested on 1,800 barramundi juveniles (weight: 71.1 g) over 51 days in a recirculating aquaculture system (RAS). The final body weight (FBW) of fish fed with BSFM reached 222.2 (± 8.7), with a thermal-unit growth coefficient (TGC) of 4.33 (± 0.15) and a feed conversion ratio (FCR) of 1.04 (± 0.01). While BSFM and SPCM inclusion did not significantly impact FBW, body weight gain (BWG), TGC, or survival rates (P >0.05), FCR increased. BSFM significantly raised total feed intake (P<0.05) but did not affect daily feed intake (P >0.05). Importantly, BSFM and SPCM inclusion did not alter diet apparent digestibility coefficient (ADC) for any nutrient groups (P >0.05), with BSFM showing high ADC for dry matter (76.8%), crude protein (93.2%), and gross energy (83.9%). No significant difference (P >0.05) was observed in these ADCs between BSFM and SPCM. The high digestibility of BSFM in warm seawater RAS (29.4°C) under high stocking density (33.7 kg m−3) supports its efficacy in contemporary barramundi farming.

Effect of Different Ages of African catfish (Clarias gariepinus) Broodstock on Reproductive Performance and Fries Production

This study was conducted at the hatchery complex of Akwa Ibom State University to investigate the effect of different ages of African catfish (Clarias gariepinus) on their reproductive performances. Eighteen (18) broodstock of Clarias gariepinus (3 males and 3 females) from each age group, six months, twelve months and eighteen months old with average body measurement of 1.1kg and 32cm for six month, 1.8kg and 43cm for 12 months and 2.5 kg and 65.7cm for 18 months were selected from AKSU fish farm labeled treatment A, B and C for the study. 3 male broodstock from each treatment were sacrificed for milt extraction without hormonal inducement. The milt from each treatment were separately pooled into one volume and divided into three portions each diluted with 2ml of normal saline solution. Three female broodstock from each treatment were separately induced with ovaprim at a single dosage of 0.5ml/kg body weight of fish and allowed for a latency period of ten hours at water temperature of 26oC before stripping manually. 3g of egg from each broodstock was mixed with the diluted milt and activated with 100 mls of normal saline. The fertilized eggs were incubated in aerated indoor concrete tanks in 3 replicates. % fertilization were accessed six (6) hours after incubation, % hatchability was accessed twenty-six hours (26) after incubation, while the percentage survival and fry production success in each treatment was accessed after ten (10) days post hatching. The results reveal that the reproductive parameters considered in this study significantly (p<0.05) increased with age of broodstocks. The percentage fertilization of egg from the least to the oldest broodstock were 63.67± 0.88, 69.50 ± 0.87 and 81.83 ± 5.05 respectively. The percentage hatchability of the oldest broodstock was 82.62 ± 1.6 significantly (P< 0.05) higher than 64.79 ± 2.74 (12 months) with the least value of 49.04 ± 5.76 recorded for six-month-old broodstock. The oldest broodstock had the highest percentage survival 83.14 ± 3.16 and fry production success of 56.05± 0.06 while the least broodstock (6-month-old) had the least value of survival 54.59 ± 2.42 and fry production success of 17.17 ± 2.59%.

Composition of gillnet catches based on network size at UPT Fishery Port of Riau Province

Gill net catches are one of fishermen's dominant fishing gear at UPT Dumai City Fishing Port. Gill net catches are easy to operate, have a low price, and are durable. This research was conducted in July-August at UPT Port of Fisheries, Riau Province. This study aimed to determine differences in gill net catches based on different mesh sizes. The method used is the survey method. The catch of gill nets by type with a mesh size of 2 inches is 25 fish species. Based on the weight and number of individual fish, it was dominated by lomek (Harpodon sp), namely 1,359.5 kg or 21.5% and 16,314 individuals or 27.18%. The catch in the 3-inch mesh size was 23 species of fish. The percentage of catches based on weight dominated by senangin (Eleutheronema tetradactylum) was 30.38% (1,353.5 kg), and based on the number of individuals dominated by pomfret of 18.72% (4,534 individuals). The main catches in gill nets at UPT Dumai are lomek (Harpodon sp), senangin (Polynemus sp), pomfret (Bramidae sp) and machete (Chirocentrus sp). The primary and bycatch yields for the 2-inch mesh were 51.58% and 42.42%, while the 3-inch mesh sizes were 57.99% and 42.01%.

Endo-Parasites of some Fresh Water Fish in Zobe Dam, Dutsin-Ma, Kastina State

Parasites of fish, either external or internal constitute one of the major problems to fish health and also a great concern; since they often cause disease conditions in fish which can also be transferred to man, The study is aimed to identify the endo-parasites of some fresh water fish in Zobe dam Dutsin-Ma, Kastina State. A total of 180 fish were collected from 3 different fish species. The collected Fish samples were transported in a cool bucket containing ice flex to the Biology laboratory. The fishes were weighed and placed on a dissecting tray for proper dissection in order to reveal the internal organs. They were centrifuge and the content was place on a slide for microscopic examination. The total number of the parasite based on class were 37 and varies according to the fish species. Oreochromis. niloticus and Clarias. garienpinus had the highest number of parasites with a total of 15 and 12 respectively while Bargus bayard had the lowest parasite load with 10 parasites. The highest mean fish weight recorded in this study is 0.21kg with percentage infection of 40%. The sizes of the fish species are all within the range of 9–38cm, the longest fish has size range of 1 to 38 with percentage infection of 40%. This result therefore suggests that there were various fish parasites from fish sample collected from Zobe dam and fish should be properly cooked or smoked before consumption to avoid health risk due to some these parasites.

The Utilization of IoT Using Grow My Fish App in African Catfish (Clarias sp) Cultivation Employing Biofloc Technology in Apung Village, Bulungan Regency, North Kalimantan Province

This research aims at introducing the Grow My Fish application (or app) as an IoT for collecting and processing data on water quality in biofloc tank for cultivators. IoT in itself has been widely used by several sectors, and one of them is the fisheries sector. Grow My Fish is an app specifically designed to support research in the fisheries field. This research was conducted in Apung Village, Tanjung Selor District, Bulungan Regency from October through December 2023. Biofloc is an innovation in fisheries field. It is known as an eco-friendly innovation thanks to its ability to process the wastes produced by fish into natural feed in the assistance of the probiotic that was mixed into the water. However, the persistent main issue until recently in this biofloc innovation is water quality. Many cultivators so far recorded their water quality measurements on a book. This made it a little hard for these cultivators to process the data. For this reason, an IoT that facilitated cultivators in processing the data on water quality, mortality, fish weight, and amount of feed was born.

Growth performance and condition factor of <i>Oreochromis niloticus</i> (Linneaus, 1758) after exposure to chemically dispersed Bonny Light crude oil

Dispersants are employed in oil spill situations to emulsify the oil into the water column thereby, facilitating weathering; this is without consideration for aquatic life and productivity. A renewal static bioassay was used to assess the recovery of Oreochromis niloticus after exposure to water accommodated fraction of dispersed Bonny Light crude oil (WAFDCO) and water accommodated fraction of Bonny Light crude oil (WAFCO) at sub-lethal concentrations of 0.2, 0.4, 0.8 and 1.6ml/l, based on the growth performance and condition factor after 49-days exposure and 54-days grow-out phases. The results showed that, the physicochemical parameters of the test media were affected by the concentrations of WAFDCO and WAFCO. The mean weight gain of O. niloticus increased with time in the exposure regimes/concentrations. Growth performance was concentration dependent, the highest mean weight of fish (15.67±0.78g) was from 1.6ml/l concentration of the WAFCO, which was higher than the control. The mean relative growth rate was higher (10.40±0.69%) in the fish from WAFCO while the highest mean specific growth rate (0.85±0.05%) was from WAFDCO. The highest value (3.42) of condition factor (K), was obtained in the 1.6ml/l of the WAFDCO. The K values of the fish from the WAFDCO were slightly higher than those from the WAFCO, which were lower than the control. Condition factor was greater than three which implied that, the fish were in good state, thus, their recovery was good after removal from the contaminated environment; hence, all mitigative actions should be prompt during and after oil spills.

The fish weight at slaughter influences energy and environmental performance of fish farming: The case of Nile tilapia production in cages

The goal of this study was to evaluate the energy and environmental performance over the life cycle of Nile tilapia production for harvesting in different weight. The reference flow was 1 t (megagram – Mg) of fished Nile tilapia with the following weight: 0.6 kg, 0.9 kg, 1.2 kg, 1.5 kg, 1.8 kg and 2.0 kg. The inventory was defined for the stages of feed production and fish production with the processes for fingerlings, followed by rearing of juvenile and fattening of adult in cage. In addition, the inventory covered the supply of the remaining material and energy inputs, transport, infrastructure and waste management. The assessed categories were area occupation, water consumption, energy demand, global warming, acidification and eutrophication. Even though the smaller-sized fish demanded more fingerlings to produce 1 t of Nile tilapia than the larger ones, the feed conversion of the smaller-sized fish was more favorable compared to that of the larger-sized fish. The energy and environmental burden of Nile tilapia showed a tendency to increase with larger-sized fish. The largest contribution of area occupation, water consumption, energy demand and global warming was from feed production, while that of acidification and eutrophication was from the rearing and fattening processes of fish production. The choice of feed ingredient suppliers from more efficient and clean sources at feed production and the control of feed loss at fish production are key strategies to improve the energy and environmental performance of the fished Nile tilapia. Therefore, the sustainability of pisciculture must consider feed production from more eco-efficient ingredients, higher efficiency in feed conversion, control of feed loss, and the use of production effluent.

Adaptive responses of feeding and swimming behaviors in black rockfish, Sebastes schlegelii, under starvation at juvenile and young stages

Starvation is a ubiquitous stress that many fish species have to cope with. To investigate the behavioral responses under this pressure in the fry stage, black rockfish (Sebastes schlegelii) at juvenile (29 days of age, 15.2 ± 1.0 mm in total length) and young (51 days of age, 40.3 ± 1.2 mm in total length) stages were starved for 12 and 21 days, respectively. During these two periods of starvation, the starved and routinely fed individuals (serving as the control group) were sampled to be analyzed the variations in growth, survival, feeding activity, swimming ability (cruise and burst), and diet transition process. The results indicated that juveniles were more sensitive to hunger, and the point of no return (PNR) was approximately 5.5 days (19 ℃ in water temperature). In contrast, the young fish had a significantly higher tolerance to starvation because the survival rate after 21 days of starvation was still higher than 99% (20 ℃). The total length and body weight of juveniles and young fish showed different degrees of negative growth. After the starvation for 1 day, the juveniles’ feeding activity on shrimps increased significantly (p < 0.05), while their cruising speed and time changed insignificantly. Similar results were observed in young fish been starved for 1–3 days. With the prolongation of starvation, however, both the feeding and cruising activities of black rockfish became significantly lower than those of the control groups (p < 0.05). The burst swimming ability did not seem to be affected by starvation time. Although the short-term starvation would not increase the young fish’s predation on shrimp, it might be serviceable for improving their feeding vitality. These behavioral results would help us understand the adaptive processes and response mechanisms of fish under starvation.

Studi kepadatan ikan sidat (Anguilla Spp) di Sungai Tarus Desa Mata Air Kabupaten Kupang pada bulan September sampai Oktober

The research conducted over approximately 60 days at Tarus River, Mata Air Village, Kupang Regency aimed to assess the variety and abundance of eel fish, a high-value commodity in the international market. The study focused on three stations along the river, where the density of eel fish was observed: station 1 (8 individuals), station 2 (5 individuals), and station 3 (2 individuals). Using digital scales, researchers measured the total weight of the caught fish, alongside noting the types of eel fish obtained. The findings, analyzed descriptively and presented through tables and figures, revealed the prevalence of eel fish type A. marmorata during the research period, primarily in the yellow eel and elver phases with varying sizes. Morphometric measurements indicated that Anguilla marmorata specimens typically ranged in total length (35-47 cm), dorsal length (20-30 cm), anal length (15-25 cm), head diameter (5-7 cm), body diameter (7-9 cm), and total weight (170-181 grams). Additionally, water quality assessments at the research site indicated temperatures ranging from 20-27oC, with a pH of 7.5.&#x0D; &#x0D; Keywords: Identification, eel fish (Anguilla marmorata).

Toxicity and therapeutical impacts of Bee venom (Apis mellifera L.) on Nile tilapia juvenile (Oreochromisniloticus)

Bee venom (BV) has been widely studied for its therapeutic properties in various medical applications. However, its effects on aquatic organisms, particularly Nile tilapia (Oreochromis niloticus), remain poorly understood, particularly concerning toxicity and therapeutic impacts. This study investigated the effects of bee venom (BV) injection on Nile tilapia (O. niloticus) by examining growth, feed efficiency, biometric parameters, whole-body chemical analysis, and the activity of antioxidant enzymes in the liver. Nile tilapia juveniles were injected with BV at doses of 0, 3, 6, 9, and 12 mg/kg of fish weight. Observations were made on the 14th day post-injection (DPI). No significant differences were found in growth, feed utilization, survival rate, biometric indices, and whole-body composition among the BV dosage groups. Similarly, the activity of intestinal enzymes (amylase, protease, and lipase) showed no significant changes. However, the study revealed a time-dependent response of antioxidant enzymes (SOD, CAT, and GPx) in the liver, with activity peaks on the 4th and 6th DPI. On the 14th DPI, fish injected with BV at doses of 3, 6, and 9 mg/kg exhibited higher antioxidant enzyme activities compared to the control and the highest dosage group (12 mg/kg). These results imply the presence of potential adaptive antioxidant activity and a favorable influence on the health and immune responses of Nile tilapia following BV injection. Notably, the effects appear to vary with the dose, influencing both antioxidant enzyme activities and immunity. Further research is warranted to explore the long-term effects of BV exposure and its potential therapeutic applications in aquaculture.

Parasite in the Mackerel (Rastrelliger sp.) Landed in the Atapupu TPI

Mackerel (Rastrelliger sp.) is a pelagic fish commodity that has high economic value because mackerel is a consumption fish and is easily found in all sea waters in Indonesia. Mackerel is a fish that is hunted for consumption because of its high omega-3 content, so it is really necessary for us to pay attention to the quality of the mackerel from the threat of parasites that can cause disease. This research was being conducted to determine the distribution of endoparasite microhabitats, intensity, prevalence, and the relation between the length of the fish and weight of fish with the number of parasites. The research samples were collected from TPI Atapupu which was carried out from November 2023 to December 2023. The research used a descriptive quantitative method and the sampling method was carried out by random sampling. The total samples of fish examined were 50 fish species, R. Kanagurta (50 fish)

Microplastics and heavy metals in freshwater fish species in the southwestern region of Bangladesh: An emerging concern for public health

Microplastics (MPs) pollution and its associated toxicity raising concerns among scientists as a result of their toxicological impacts on human health and the ecosystem. This study aims to investigate the microplastics and heavy metals (HMs) contamination in seventeen freshwater fish species collected from the Southwestern region of Bangladesh. Microplastics extracted from these species using the hydrogen peroxide digestion method and characterized by Attenuated Total Reflection- Fourier Transform Infrared Spectroscopy (ATR-FTIR). Atomic Absorption Spectrometry (AAS) was used to determine the concentration of HMs in different species for evaluating human health risks. A total of 142 microplastic particles were extracted with an average concentration of 1.13 ± 0.84 items per individual of fish, where the highest microplastics were found in C. punctata (3.43 ± 3.15 items) and lowest in A. mola (0.14 ± 0.38 items). Identified microplastics were dominated by < 1 mm size (87.3%), black color (60.6%), and fiber shape (94.4%). Polyethylene (73.08%), polypropylene (21.15%), and polystyrene (5.77%) were the most prevalent among the identified microplastic polymers. A positive correlation was found between microplastic numbers and fish weight and length. Low to moderate human health risks were associated with microplastics. The concentration (mg/kg) of heavy metals in studied fish samples was Cr (0.47–2.89; 0.79 ± 0.56) > Cu (0.01–1.14; 0.50 ± 0.44) > Pb (0.04–0.58; 0.22 ± 0.12) > Cd (0.00–0.11; 0.03 ± 0.03), respectively. Heavy metals-based human health risk assessment results show that there are no major non-carcinogenic health risks (THI<1), while higher carcinogenic risks are present for consumers.

Male reproductive output and sperm competition as indicated by gonadosomatic index in Paddlefish stocks

AbstractObjectiveWe investigated if large Paddlefish Polyodon spathula invest in testis weight disproportionately more than smaller males, as expressed by the gonadosomatic index (GSI). The approach was to assess the relation between testis weight F (i.e., the combined weight of both testes) and fish weight W in the expression F = aWb. The hypothesis was that sperm competition in Paddlefish would be expected (with b &gt; 1) based on observations of several male fish attending a female spawner in a past study in the Osage River, Missouri.MethodsWe used a large, three‐state data set from three fisheries (Montana, North Dakota, and Oklahoma) to evaluate isometry and allometry in the power function relationship between fish weight and testis weight.ResultAll three data sets showed hyperallometric increases in testis weight with fish weight (i.e., b &gt; 1). For Montana males, hyperallometry was greatest (b = 1.56; n = 8798), followed by North Dakota (b = 1.36; n = 8209) and Oklahoma (b = 1.22; n = 9571). Paddlefish from Montana and North Dakota had much lower testis weights through age 18 and much lower fish weights through age 25 than Oklahoma Paddlefish. By ages 17–25, mean male GSI in Oklahoma declined, whereas it remained level at about 1.5 for combined Montana and North Dakota Paddlefish. Throughout their lives, at each age, Montana and North Dakota Paddlefish allocated a higher percentage of their total weight to testis weight and reached a higher asymptotic GSI (GSI∞) than did Oklahoma Paddlefish; GSI∞ was 1.50 for Montana fish, 1.44 for North Dakota fish, and 1.26 for Oklahoma fish.ConclusionResults provide evidence supporting the occurrence sperm competition (i.e., b &gt; 1), as would occur when two or more males compete to fertilize the eggs of a female spawning Paddlefish. Comparisons among species and stocks are made but were limited by an acute shortage of data on male testis weights and other testis characteristics (e.g., sperm size, energy content), and reproductive investment in Paddlefish and most other fishes in other localities.

Efficiency of using experimental feeds with different levels of nutrition in feeding rainbow trout

The article presents the results of research on the growth dynamics of rainbow trout from fingerling to marketable fish using feeds with different compositions of components and nutrient contents. For the experiment, two age groups of rainbow trout individuals, control and experimental, were formed, which were kept in tanks with a total volume of 30 m3 and fed with feeds with different nutrient contents. For feeding the experimental fish, dry pelleted feed for trout was used, which has an optimal balance of cost and nutritive value, resulting in high growth rates with a low feed coefficient. The feed is made from high-quality Ukrainian ingredients with good nutritional and flavor characteristics, stimulating fish feed intake, and is balanced in terms of essential nutrients and biologically active substances, which positively affects the physiological condition of salmonid fish and their growth rates. The daily ration was determined depending on the fish's weight and the water temperature in the tanks according to the feed manufacturer's recommendations. The effectiveness of using pelleted compound feeds for trout was evaluated based on indicators such as fish survival, fish productivity, and feed consumption. At the same time, the physicochemical parameters were monitored throughout the entire experimental period. The duration of growing rainbow trout fingerlings was 245 days. As a result, 3230 specimens of fingerlings with a mass of 25.6 g were obtained in the control, and 3400 specimens were obtained in the experiment with a mass of 28.5 g. The yield from the cultivation was 76 % and 80 %, respectively. Fish productivity was slightly higher in the basin where the experimental group of fingerlings was kept. The total weight of the harvested fish from the experimental group was greater by 14.2 kg. To obtain marketable products, rainbow trout fingerlings were stocked in 30 m3 tanks. The average weight of fish in the control group at stocking was 25.6 g, and in the experimental group, it was 28.5 g. 3100 specimens of fingerlings were stocked in each tank. The duration of cultivation was 215 days. 2805 specimens were harvested from the tanks, 250.5 g from the control tank, and 268.5 g from the experimental tank. The total weight of the harvested fish and fish productivity were slightly higher in the fish from the experimental group. As a result of the conducted research, it was established that feeding fish with feeds differing in nutritional value contributes to increasing the productivity of rainbow trout farming.

Fish weight reduction in response to intra‐ and interspecies competition under climate change

AbstractAs described by the temperature–size rule paradigm, fish living in warmer temperatures grow faster but have a smaller mature body size. However, the changes in the body size of fish communities in the western North Pacific, which is one of the most active fishing grounds, remain unclear. This study aimed to investigate changes in the body size of fish assemblages in the western North Pacific and whether fish sizes were potentially driven by the temperature–size rule, bottom‐up effects and intra‐ and interspecies competition at a community scale. We evaluated the fish weight data of 6 stocks of 4 species from 1978 to 2018 and 17 stocks of 13 species from 1995/1997 to 2018. Weight reduction in the fish assemblage was observed in the 1980s and was associated with the biomass peak of the Japanese sardine (Sardinops melanostictus), indicating the effect of intra‐ and interspecies competition. Another weight reduction was observed in the 2010s, which was associated with a moderate increase in the biomass of the Japanese sardine and chub mackerel (Scomber japonicus). Our analyses indicate that stronger stratifications in the surface layers during the 2010s potentially reduced the nutrient supply from the subsurface to the surface layers. This limitation in food availability forced intra‐ and interspecies competition under a moderate increase in fish biomass. Our findings underscore the critical significance of integrating the impacts of species competition and climate change on fish sizes to improve fishery management at a community level.

Effects of different stocking density start-up conditions on water nitrogen and phosphorus use efficiency, production, and microbial composition in aquaponics systems

Controlling environmental parameters, including nitrogen and phosphorus use efficiency, is a crucial aspect of maintaining effective aquaponic systems. In this study, we evaluated the impact of start-ups under high (20 kg/m3) and low (5 kg/m3) stocking density conditions on water quality, productivity, nitrogen use efficiency (NUE), phosphorus use efficiency (PUE), microbial community compositions, and functional genes in the aquaponics system. Six experimental units (three replications per treatment) were categorized into two groups. The experimental process was divided into two phases: Phase I (Days 1–40) and Phase II (Days 41–145). During Phase I, the two system groups were initiated under high and low stocking densities. Phase II constituted the fish and vegetable production phase, with all aquaponics systems standardized at a stocking density of 10 kg/m3 and a planting density of 12 plants/m2. The results indicated superior water quality in the low aquaponics systems than that in the high aquaponics systems during Phase I, whereas the opposite was observed during Phase II. The final weight, specific growth rate, and fish weight gain of jade perch (Scortum barcoo), as well as the plant weight gain of tomato plants, were significantly higher in the high aquaponics system than those in the low aquaponics system. The NUE and PUE of the high aquaponics system were 49.55 ± 1.02% and 60.12 ± 1.28%, respectively, surpassing those of the low aquaponics system (43.41 ± 2.16% and 49.06 ± 1.59%). The microbial diversity in the moving bed biofilm reactor and roots of the high aquaponics system was lower than in the low aquaponics system. However, the relative abundances of nitrifying and denitrifying bacteria were higher than those in the low aquaponics system. The number of copies of functional genes for nitrification and denitrification, including amoA, nxrB, nirS, nirK, and nosZ, was higher in the high aquaponics systems. Overall, the results indicated that high aquaponics systems initiated with high stocking density yield more products, improved water quality, and higher NUE and PUE by altering the composition of microbial communities. This study presents a method for enhancing the functional microbial community of a system by optimizing conditions during the initiation period.

Assessment of Full-Fat Tenebrio molitor as Feed Ingredient for Solea senegalensis: Effects on Growth Performance and Lipid Profile.

Tenebrio molitor (TM) is considered as one of the most promising protein sources for replacing fish meal in aquafeeds, among other things because it is rich in protein, a good source of micronutrients and has a low carbon footprint and land use. However, the main drawback of TM is its fatty acid profile, in particular its low content of n-3 PUFA. This study evaluates the effects of partially replacing plant or marine-derived with full-fat TM meal at two different levels on growth performance and lipid profiles of Senegalese sole (Solea senegalensis). For this purpose, a control diet (CTRL) and four experimental isoproteic (53%) and isolipidic (16%) diets were formulated containing 5 and 10% TM meal replacing mostly fish meal (FM5 and FM10), or 10 and 15% TM meal replacing mostly plant meal (PP10 and PP15). Fish (215 g) were fed at 1% of their body weight for 98 days. The final body weight of fish fed the experimental diets containing TM meal was not different from that of fish fed the CTRL diet (289 g). However, the inclusion of TM meal resulted in a gradual improvement in growth rate and feed efficiency in both cases (replacement of fish or plant meals), and significant differences in specific growth rate (SGR) were observed between fish fed the CTRL diet (SGR = 0.30% day-1) and those fed diets with the highest TM meal content (PP15; SGR = 0.35% day-1). The experimental groups did not show any differences in the protein content of the muscle (19.6% w/w). However, significant differences were observed in the total lipid content of the muscle, with the FM10, PP10, and PP15 groups having the lowest muscle lipid contents (2.2% ww). These fish also showed the lowest neutral lipid content in muscle (6.6% dw), but no differences were observed in the total phospholipid content (2.6% dw). Regarding the fatty acid profile, fish fed FM10, PP10 and PP15 had lower levels of linoleic acid (18:2n-6) and higher levels of oleic acid (18:1n-9) in liver and muscle compared to fish fed CTRL. However, no differences were found between fish fed CTRL and TM-based diets for docosahexaenoic acid (22:6n-3) and total n-3 PUFA in liver and muscle. In conclusion, our study demonstrated that full-fat TM inclusion up to 15% in S. senegalensis diets had no negative effects or even some positive effects on fish survival, growth performance, nutrient utilization and flesh quality.

Growth Performance and Environmental Quality Indices and Biomarkers in a Co-Culture of the European Sea Bass with Filter and Deposit Feeders: A Case Study of an IMTA System

This study aimed to evaluate the efficiency of an integrated multi-trophic aquaculture (IMTA) system comprising co-cultured fed fish and organic extractive species representing three distinct trophic levels as well as the impact and potential utilization of two commercially available fish feeds made up of 35% fish meal (FM) and 20% fish meal (LFM) ingredients, using a multi-indicator assessment approach. Significant alterations were observed in growth performance indicators (GPIs), water and sediment quality indices, toxicity tests and biomarkers within the IMTA system. The fish survival, weight gain (WG), and specific growth rate (SGR) were higher in the IMTA system with significantly lower feed conversion ratios (FCRs) and higher feed efficiency (FE) in comparison to the fed fish monoculture system. Yet, organic filter feeders displayed 100% survival, and increased shell growth, while deposit feeders exhibited successful survival and significant weight gain. In the comparison between FM-IMTA and LFM-IMTA, fed fish in FM-IMTA showed higher WG, SGR, and FE with lower FCR. Environmental parameters like temperature, oxygen, and nutrient concentrations fluctuated but generally improved in the IMTA system, indicating lower mesotrophic conditions. Sediment fatty acid profiles differed between systems and toxicity assessments, which suggested a lower impact in IMTA and FM-IMTA systems. The sediment microbial community displayed high similarity within IMTA systems and between FM-IMTA and LFM-IMTA. These findings underscore the potential of IMTA systems for sustainable aquaculture, emphasizing improved growth performance and reduced environmental impact, particularly when using fish meal feeds.