Growth Rate Values Research Articles

THE EFFECT OF DIFFERENT SALINITY ON GROWTH RATE AND SURVIVAL RATE OF POST-LARVA (PL-9) VANNAME SHRIMP ( Litopenaeus vannamei )

Vannamei shrimp (Litopenaeus vannaemi) is one of the largest fisheries commodities in Indonesia. The first step in the success of vannamei shrimp cultivation is seeding. The success of the hatchery will support efforts to provide quality shrimp seed . The research method used is experimentation with descriptive quantitative data analysis. Calculation using a completely randomized design test with the help of SPSS. The results of water quality measurements showed an average temperature of 26.26oC - 28.8oC. The pH ranges between 7.32-7.68. For DO it ranges from 5.2 mg/l -6.6 mg/l. For Ammonia it ranges from 0.2 ml/lt - 0.54 ml/lt. Water quality measurements were carried out for 14 days in the morning and evening. Based on these results, it can be concluded that the growth rate, survival rate, and biomass increase value, the salinity value in treatment 1 (26 ppt) shows the highest compared to the salinity values in the other treatments. Meanwhile, the value of water quality measurements based on SNI 8678-4:2021 shows that the temperature is still below standard, the pH scale is still atstandard, the DO value is still at standard value, and the value for ammonia exceeds standard limits .

Effects of dietary inclusion of Bacillus amyloliquefaciens AV5 on growth performance, antioxidant activity, innate immune, and hematological responses in Nile tilapia (Oreochromis niloticus) reared at low and high stocking densities

This research work investigated the efficacy of Bacillus amyloliquefaciens AV5 in mitigating the stress effects of stocking densities in Nile tilapia (Oreochromis niloticus). 520 healthy Nile tilapia fingerlings (24.43 ± 1.4g) were randomly allocated to 16 plastic tanks, each with a capacity of 400L. Two stocking densities were tested: low density (37.5 fish/m³) and high density (125 fish/m³) with four treatment groups(low density with a control diet (LDC), high density with a control diet (HDC), low density with a supplemented diet (LDS), and high density with a supplemented diet (HDS)) for 8 weeks. HDC exhibited lower values (P < 0.05) for specific growth rate, final weight, weight gain rate, and specific growth rate than fish fed at LDC, LDS, and HDS. The lowest feed conversion ratio was recorded at the LDS and HDS. There were no significant differences (P > 0.05) in survival rates among treatments. There were no notable disparities (P > 0.05) in the LDC, LDS, and HDS body composition. Antioxidant enzyme activities were greater in LDC, LDS, and HDS than in HDC, while malondialdehyde levels were higher in HDC, and hematology parameters in HDS were improved compared to HDC. Elevated levels (P < 0.05) of phagocytic and lysozyme activity were seen in LDS and HDS. There was no change in glucose levels in HDS and LDC. Nonetheless, cortisol was elevated in HDC compared to LDC, LDS, and HDS. Hence, B. amyloliquefaciens AV5(1 × 108 cfu/g) is a potential probiotic to alleviate HDC-induced stress in O. niloticus.

Morphological, ecological and genetic characteristics of the sandy sculpin (&lt;i&gt;Leocottus kesslerii&lt;/i&gt;, Cottidae) from the lakes Baikal, Arakhlei and Gusinoe, Transbaikalia

Studies on local forms of the Sandy sculpin, Leocottus kesslerii, in the lakes Baikal, Arakhlei and Gusinoye show that the differences between lake forms in terms of external morphology lie in the head length to width ratio. In the Baikal form, the head is wider than long, vs the opposite in both Apakhlei and Gusinoe forms. In the Baikal and Gusinoe forms, there is a gap between the dorsal fins, a gap being absent from the Arakhlei form and the dorsal fins are in touch with each other. In the Arakhlei form, the anal fin is long (37.4–43%, on average 39.3% SL). In the Baikal form, the length of the A base reaches 32.9% SL (29.0–34.5%). In the Baikal and Arakhlei forms, small and sparse bone prickles are present on the body, these being large and dense in the Gusinoe form. The differences identified show a low level of morphological isolation of the forms. More significant differences are established in ecological features: growth rate, food spectrum, reproductive characteristics, and fecundity values. The differences in ecological features are due to the adaptation of the Sandy sculpin forms to specific conditions of the lakes they inhabit. Studies on genetic differentiation were carried out using the control region (CR) of mtDNA. The study forms of the Sandy sculpin revealed weak genetic isolation. The p-distances between the L. kesslerii forms averaged from 0.33 ± 0.12 to 0.51 ± 0.24%. Such low values of genetic distances clearly lie within the limits of intraspecific variability. The data obtained on the morphological, ecological and genetic differentiation of lake forms of the Sandy sculpin show that fish from the lakes Baikal, Arakhlei and Gusinoe belong to the same nominative subspecies, Leocottus kesslerii kesslerii.

Impact on Local Economy from Zhoushan National New Area

To empirically study the policy impact of a National New Area on the local economy, this paper evaluates the effect of the Zhoushan Archipelago New Area on local GDP growth rate and economic efficiency. Firstly, the economic efficiency of 20 prefectural-level cities in Jiangsu, Zhejiang and Anhui provinces is estimated by data envelopment analysis with input and output data from 1995 to 2015. In selecting some cities except Zhoushan as a control group, we construct some counterfactuals of Zhoushan by a panel data approach. The difference between the actual and counterfactual values for the GDP growth rate and economic efficiency of Zhoushan is calculated and compared to conclude the treatment effect of the National New Area. The research shows that in the first four years, the policy of the National New Area promoted Zhoushan's economic quality by raising its efficiency, but relatively reduced its economic quantity by negatively affecting the local GDP growth rate. Then the policy influence on Zhoushan’s GDP growth rate and economic efficiency gradually disappeared after four years. Combining some other research on our study, we find that the policy effect on the GDP growth rate is related to the level of economic growth in these areas. The policy of the National New Area has less influence on GDP growth if approved in the developed region rather than in the undeveloped region. We think that it is better to set up a National New Area in a relatively undeveloped area.

Influence of Storage Methods on the Vitality and Growth Rate of Macrofungi

The work contains a comparative analysis of methods for storing pure cultures of macrofungi. The study used 20 species of macrofungi from various taxonomic and ecological-trophic groups. Storage was carried out using five methods: serial subculturing, storage under a layer of distilled water and three cryopreservation protocols: a protocol using blocks of agar medium, a “perlite protocol” and a “grain protocol”. For the selected cryostorage methods, various cryoprotective compounds (glycerol, trehalose) were used. Radial growth rate was used as a criterion for the state of crops. The values of the radial growth rate obtained immediately after isolation of the pure culture were chosen as the control. It has been shown that the most favorable for preserving the physiological activity of cultures are the storage method under a layer of distilled water, “perlite” and “grain” cryopreservation protocols.

Effects of Dietary Microalgae Schizochytrium sp. Supplementation on Growth Performance and Skin Color in Jack Dempsey cichlid (Rocio octofasciata)

Growth retardation and decreased vivid coloration are significant issues in the ornamental fish market, particularly among cichlids. This study investigates the effects of Schizochytrium sp. microalgae supplementation on the growth and skin coloration of the Jack Dempsey cichlid (Rocio octofasciata). Three experimental groups were established: a control group (C) with no supplementation, and two microalgae-supplemented groups with 0.5% (S05) and 1% (S10). The control group was fed a commercial diet, while the S05 and S10 groups received the microalgae mixed with the commercial feed via spraying. A total of 135 Jack Dempsey fish (mean initial weight: 1.17 ± 0.14 g) were stocked into nine glass tanks (100 L each), with three replicates per group. After a 60-day feeding trial, growth indices revealed significant differences (p&lt;0.05) between the control and algae-supplemented groups. The S10 group exhibited the highest final weight (FW) and the lowest feed conversion ratio (FCR). Additionally, the weight gain (WG) and specific growth rate (SGR) values for the S10 group were significantly higher than those of both the control and S05 groups (p&lt;0.05). However, skin color parameters, including L* (brightness), a* (+red/-green axis), b* (+yellow/-blue axis), chroma (Ch), and hue angle (Hue), showed no statistical differences among the groups. This study demonstrates that a diet supplemented with 1% Schizochytrium sp. can enhance growth parameters and serve as a beneficial feed additive for Jack Dempsey cichlids.

Growth Rate Assessed by Vascular Deformation Mapping predicts Type B Aortic Dissection in Marfan Syndrome.

Patients with Marfan syndrome (MFS) are at a high risk of type B dissection (TBAD). Aortic growth and elongation have been suggested as risk factors for TBAD. Vascular deformation mapping (VDM) is an image analysis technique for mapping 3D aortic growth on rouine computed tomography angiography (CTA) scans. We aimed to use VDM to examine the value of aortic growth rate in the descending thoracic aorta (DescAo), among other imaging biomarkers, to identify the factors associated with risk of TBAD in MFS. CTA scans spanning 2004-2023 from adult MFS patients with native DescAo were analyzed by VDM. Other measurements included multi-level thoracoabdominal aortic diameters and the length of the DescAo by centerline analysis. Among the 105 MFS patients analyzed, 63.8% were male, with median age of 40 years (range 18-73) and a median surveillance interval of 5.3 years (range 2.0-18.3). During surveillance, 12 (11.4%) patients developed TBAD. Patients with TBAD had higher radial growth rate (0.63 vs. 0.23 mm/year; p < 0.001) and elongation rate (2.4 vs. 0.5 mm/year; p < 0.001), on univariate and multivariable analysis, but pre-dissection descending aortic diameter was not significantly different. Predictors of growth rate included younger age, higher baseline maximal diameter of the DescAo, smoking history and warfarin use. Radial growth and elongation rates of the DescAo were independent predictors of TBAD occurrence in MFS. TBAD often occurred in at non-aneurysmal diameters. These findings emphasize the role of growth over absolute diameter in risk stratification for TBAD in MFS.

Influence of Storage Methods on the Vitality and Growth Rate of Macrofungi.

The work contains a comparative analysis of methods for storing pure cultures of macrofungi. The study used 20 species of macrofungi from various taxonomic and ecological-trophic groups. Storage was carried out using five methods: serial subculturing, storage under a layer of distilled water and three cryopreservation protocols: a protocol using blocks of agar medium, a "perlite protocol," and a "grain protocol." For the selected cryostorage methods, various cryoprotective compounds (glycerol, trehalose) were used. Radial growth rate was used as a criterion for the state of crops. The values of the radial growth rate obtained immediately after isolation of the pure culture were chosen as the control. It has been shown that the most favorable for preserving the physiological activity of cultures are the storage method under a layer of distilled water, "perlite" and "grain" cryopreservation protocols.

Rapid growth rate of Enterobacter sp. SM3 determined using several methods

BackgroundBacterial growth rate, commonly reported in terms of doubling time, is frequently determined by one of two techniques: either by measuring optical absorption of a growing culture or by taking samples at different times during their growth phase, diluting them, spreading them on agar plates, incubating them, and counting the colonies that form. Both techniques require measurements of multiple repeats, as well careful assessment of reproducibility and consistency. Existing literature using either technique gives a wide range of growth rate values for even the most extensively studied species of bacteria, such as Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. This work aims to apply several methods to reliably determine the growth rate of a recently identified species of Enterobacteriaceae, called Enterobacter sp. SM3, and to compare that rate with that of a well-known wildtype E. coli strain KP437.ResultsWe extend conventional optical density (OD) measurements to determine the growth rate of Enterobacter sp. SM3. To assess the reliability of this technique, we compare growth rates obtained by fitting the OD data to exponential growth, applying a relative density method, and measuring shifts in OD curves following set factors of dilution. The main source of error in applying the OD technique is due to the reliance on an exponential growth phase with a short span. With proper choice of parameter range, however, we show that these three methods yield consistent results. We also measured the SM3 division rate by counting colony-forming units (CFU) versus time, yielding results consistent with the OD measurements. In lysogeny broth at 37oC, SM3 divides every 21 ± 3 min, notably faster than the RP437 strain of E. coli, which divides every 29 ± 2 min.ConclusionThe main conclusion of this report is that conventional optical density (OD) measurements and the colony-forming units (CFU) method can yield consistent values of bacterial growth rate. However, to ensure the reproducibility and reliability of the measured growth rate of each bacterial strain, different methods ought to be applied in close comparison. The effort of checking for consistency among multiple techniques, as we have done in this study, is necessary to avoid reporting variable values of doubling time for particular species or strains of bacteria, as seen in the literature.

Design, experimental optimization, and flow analysis of a novel bioreactor for dynamic mammalian cell culture at laboratory scale using Box-Behnken design

Improving the quality of dynamic cell culture in laboratories is an important field in bioengineering. In this study, a novel lab-scale bioreactor using a vibrating agitator and a modified flask has been introduced to create a strong mixing at low shear stress. This bioreactor has been optimized using Box-Behnken design based on three dimensionless important structural factors including disc diameter, vibration amplitude, and the height of the disc placement. Three growth indicators including the specific growth rate, the natural logarithm of the maximum cell density, and productivity have been considered as biological responses. The results show that the disc diameter has the most important role in these indicators. If the disc diameter, vibration amplitude, and the height of disc placement are set to 0.24, 0.02, and 0.4 of the flask diameter, respectively, the values of the specific growth rate, the maximum cell density, and productivity at this optimum settings are 0.033 (h−1), 13.11, and 5133 (cells/(mL.h)), respectively. These values of the indicators are high and indicate the better performance of this bioreactor than other lab-scale bioreactors. In addition, investigating Reynolds number in the fluid flow indicates that in the range of 780 up to 1150, growth indices are high.

The influence of unconventional monetary policy tools: an euro area perspective

Purpose – This article aims to investigate the influence of unconventional monetary policy tools (UMPTs) employed by the European Central Bank (ECB) on the inflation rate and GDP growth rate within the euro area, motivated by the principles of the Taylor rule. Research methodology – Elastic net regression with ARIMA residuals was used to analyse the relationship between UMPTs and economic indicators, measured by adjusted R-squared. Six samples were constructed, and hypothesis testing was performed using moving block bootstrapping. Residual diagnostics were used for model validation. Findings – The study revealed significant impacts of UMPTs, particularly in combination with interest rates, on inflation rates. However, adjusted R-square values for GDP growth rate were less pronounced, indicating a more complex relationship. Research contributes to understanding the dynamics of monetary policy transmission mechanisms, informing policy institutions, and guiding future research directions. Research limitations – Limitations include the focus on the euro area and the absence of analysis in other major economies. Future research should address these limitations and incorporate additional variables for a more comprehensive analysis. Practical implications – The findings provide insight for policymakers regarding the efficacy of UMPTs in influencing inflation rates, aiding in informed decision-making in monetary policy formulation and implementation. Originality/Value – This study contributes novelty by comprehensively analysing the relationship between UMPTs and economic indicators within the euro area, providing valuable insight into monetary policy institutions, and guiding future research directions.

Growth and physiological responses of Nile tilapia, Oreochromis niloticus fed dietary fermented sugar beet bagasse and reared in biofloc system

Sugar beet bagasse (SB) is a common agro-industrial waste used in animal feeds. However, its high crude fiber content makes it difficult for fish to digest. Fermentation processes can improve the nutritional value of SB by-products. The study uses Lactobacillus rhamnosus and yeast (Saccharomyces cerevisiae) to ferment SB waste for use as a soybean meal substitute in Nile tilapia fingerlings. This led to an increase in protein, lipid, ash, and nitrogen-free extracts, while the fiber content decreased. Four experimental isonitrogenous (crude protein: 249.2 g kg−1) and isocaloric (gross energy:18.25 MJ kg−1) diets were formulated as follows: a control diet with 0 % LYFSB (L. rhamnosus and yeast fermented SB), and three other diets with LYFSB replacing soybean meal (SBM) at levels of 10 % (LYFSB10 %), 20 % (LYFSB20 %), and 30 % (LYFSB30 %) based on protein content, over a 70-day period. 180 fingerlings of Nile tilapia (average initial weight of 5.19 ± 0.02 g) were placed at random in twelve circular plastic tanks (60 L capacity) with a stocking density of fifteen fish each. Nitrite and ammonia levels decreased as the replacement levels of LYFSB in tilapia diets increased, while nitrate levels showed the opposite trend. The phytoplankton community includes nine species in the biofloc system and four in tilapia gut content, with Chlorophyceae being the most common class, having the highest number in fish-fed diets (7805.67 organism/ml). The study revealed that LYFSB significantly influenced the zooplankton community, with protozoa dominating in biofloc water and rotifer in tilapia gut. LYFSB10 % and LYFSB20 % had the highest bacteria counts. Fish fed with LYFSB10 % and LYFSB20 % diets showed the highest values for specific growth rate (2.51 % day−1) and weight gain (24.92 g fish−1). These diets also exhibited increased activity levels of trypsin, lipase, and amylase enzymes. Increasing the inclusion of LYFSB in fish diets as a replacement for FM improved the intestinal and liver health of fish. The diets with LYFSB10 % and LYFSB20 % showed the highest levels of globulin, total protein, albumin, and IgM, with no significant differences between them. Fish fed LYFSB10 % had lower cholesterol and triglyceride levels. Superoxide dismutase (SOD) and catalase (CAT) activities were highest in fish fed LYFSB10 % and LYFSB20 %, while malondialdehyde (MDA) activity was lowest in the LYFSB30 % diet. The study showed that the biofloc system enhanced water quality and increased the efficiency of tilapia fed LYFSB10 % and LYFSB20 %.

Effects of the extrusion process on the physical properties of micro pellets and the growth performance of juvenile Nile tilapia

The present study aimed to evaluate the effect of different extrusion processes on the physical properties of micro pellets and how the alterations affect the growth performance of juvenile Nile tilapia. Four experimental diets were produced with the same formulation, but with different extrusion processes: CE: cold extrusion (18 ºC); HE: hot extrusion (100 ºC); D1: double extrusion, first a hot extrusion (100 ºC) of all the ingredients followed by cold extrusion (18 ºC); D2: double extrusion, first a hot extrusion (100 ºC) of the plant-based ingredients followed by mixing with the animal-based ingredients and milling, then cold extrusion (18 ºC). Juvenile tilapia (0.83 ± 0.01 g; 3.68 ± 0.19 cm) were distributed in 20 experimental units (60 L; n=5; 20 fish per unit) in a completely randomized design for four weeks. The micro pellets of the experimental HE diet presented a positive expansion rate (2.86 ± 0.45 %) and a lower bulk density (465.9 ± 3.45 g/L). The D1 and D2 micro pellets presented higher bulk density (671.0 ± 2.98 and 612.8 ± 4.99 g/L, respectively). All the micro pellets showed high durability (>95 %). The D2 micro pellets showed low water resistance (24.4 ± 3.51 %), resulting in a high leaching rate of nutrients (>68 %). The HE and D1 micro pellets showed a higher absorption rate in water (3.65 ± 0.29 and 3.66 ± 0.21 g water/g, respectively). The water solubility index of the micro pellets was not influenced by the different extrusion processes (P > 0.05), nor were survival and feed consumption. The fish fed with the HE diet showed greater weight gain (3.84 ± 0.44 g), and the lowest weight gain was in the fish fed with the CE diet (3.05 ± 0.39 g) (P < 0.05). Feed conversion was lower in fish fed the HE (1.06) and D1 (1.11) diets (P < 0.05). Fish fed the HE diet had the highest values for relative growth rate (9.08 ± 0.62 %/d), protein retention (30.6 ± 2.61 %) and protein efficiency (2.26 ± 0.22 %) (P < 0.05). Fish fed the CE diet had the lowest values for relative growth rate (7.82 ± 0.51 %/d), protein retention (21.4 ± 2.72 %) and protein efficiency (1.55 ± 0.23 %) (P < 0.05), though the values are in line with those in the literature. In conclusion, hot extrusion resulted in micro pellets with better physical properties and fish with higher growth performance. Double extrusion, first a hot extrusion of the plant-based ingredients followed by mixing with the animal-based ingredients and milling, then cold extrusion is not recommended due to high levels of nutrient leaching. Cold extrusion and double extrusion, first a hot extrusion of all the ingredients followed by cold extrusion processing can be considered for producing micro diets for juvenile tilapia, especially when less investment in the extrusion process is desired.

Peculiarities of Hemostasis and Proteomics in Patients With Acute Myocardial Infarction and Healthy Volunteers After SARS-CоV-2 Infection.

To identify the features of plasma, platelet hemostasis, and proteomic composition of the blood plasma in patients with acute myocardial infarction (AMI) and healthy volunteers after COVID-19. The study included patients with AMI who have recently had COVID-19 (AMI-post-COVID, n=56) and patients with AMI who have not recently had COVID-19 (AMI-control, n=141). Healthy volunteers constituted the control groups and were also divided into control-post-COVID (n=32) and control-control (n=71) groups. Previous SARS-CoV-2 infection was determined by anti-N IgG in the blood serum, the level of which persists for 6-10 months after the disease. Hemostasis was evaluated by thromboelastometry (on whole blood), thrombodynamics (on platelet-poor plasma), fibrinolysis, impedance aggregometry, and proteomic analysis. The AMI-post-COVID and AMI-control groups had higher values of thrombus growth rate, size and density based on the data of thromboelastometry and thrombodynamics, as well as increased concentrations of the complement system components, proteins regulating the state of the endothelium, and a number of acute-phase and procoagulant proteins compared to the control groups. Furthermore, in the AMI-post-COVID group, compared to the AMI-control group, the thrombus density was lower, and its lysis rates were higher when measured by the thrombodynamics method on platelet-poor plasma, while the platelet aggregation induced by ADP and thrombin was higher. Also, in the control-post-COVID group, compared to the control-control group, the thrombus formation rate was lower, whereas, in contrast, the thrombus size as measured by the thrombodynamics method and the platelet aggregation induced by arachidonic acid and thrombin were higher. In addition, in the AMI-post-COVID group, compared to the AMI-control group, the concentrations of proteins involved in inflammation and hemostasis were lower. Patients with AMI who have recently had COVID-19 are characterized by a less pronounced activation of the immune response compared to patients with AMI who have not had COVID-19. This may be due to long-term chronic inflammation and depletion of components of the immune activation system after SARS-CoV-2 infection. Long-term activation of the hemostasis system in both patients with AMI and healthy volunteers after COVID-19 is primarily due to the platelet component of hemostasis.

Plankton interaction model: Effect of prey refuge and harvesting

Abstract Harmful algal blooms are one of the major threats to aquatic ecosystem. Some phytoplankton species produce toxins during algal bloom and affect other aquatic species as well as human beings. Thus, for the conservation of aquatic habitat, it is much needed to control such phenomenon. In the present study, we propose a mathematical model of toxin-producing phytoplankton and zooplankton species, which follows the Holling Type III functional response. We consider the effect of prey refuge and harvesting on both the species. Boundedness of the proposed model, existence of equilibria, and their stability have been discussed analytically. We also discuss the optimal harvesting policy and existence of bionomic equilibrium. The numerical simulation has also been performed. We identify the control parameters that are responsible for the system dynamics of the model. The parameter prey refuge has a great impact on the dynamics of the model system. Higher value of prey refuge leads to the stable dynamics. Also, the growth rate of phytoplankton acts as a control parameter for the dynamics of the model. The higher value of growth rate of phytoplankton is responsible for oscillatory behavior.

Revisiting Fishery Sustainability Targets

Density-dependent population dynamic models strongly influence many of the world’s most important harvest policies. Nearly all classic models (e.g. Beverton-Holt and Ricker) recommend that managers maintain a population size of roughly 40–50 percent of carrying capacity to maximize sustainable harvest, no matter the species’ population growth rate. Such insights are the foundational logic behind most sustainability targets and biomass reference points for fisheries. However, a simple, less-commonly used model, called the Hockey-Stick model, yields very different recommendations. We show that the optimal population size to maintain in this model, as a proportion of carrying capacity, is one over the population growth rate. This leads to more conservative optimal harvest policies for slow-growing species, compared to other models, if all models use the same growth rate and carrying capacity values. However, parameters typically are not fixed; they are estimated after model-fitting. If the Hockey-Stick model leads to lower estimates of carrying capacity than other models, then the Hockey-Stick policy could yield lower absolute population size targets in practice. Therefore, to better understand the population size targets that may be recommended across real fisheries, we fit the Hockey-Stick, Ricker and Beverton-Holt models to population time series data across 284 fished species from the RAM Stock Assessment database. We found that the Hockey-Stick model usually recommended fisheries maintain population sizes higher than all other models (in 69–81% of the data sets). Furthermore, in 77% of the datasets, the Hockey-Stick model recommended an optimal population target even higher than 60% of carrying capacity (a widely used target, thought to be conservative). However, there was considerable uncertainty in the model fitting. While Beverton-Holt fit several of the data sets best, Hockey-Stick also frequently fit similarly well. In general, the best-fitting model rarely had overwhelming support (a model probability of greater than 95% was achieved in less than five percent of the datasets). A computational experiment, where time series data were simulated from all three models, revealed that Beverton-Holt often fit best even when it was not the true model, suggesting that fisheries data are likely too small and too noisy to resolve uncertainties in the functional forms of density-dependent growth. Therefore, sustainability targets may warrant revisiting, especially for slow-growing species.

Phylogenetic, growth performance and protein growth hormone of snakehead fish (Channa striata) from wild stock in Sumatra, Indonesia

Abstract Watershed isolation may influence morphological, genetic variations, and protein expression of snakehead fish (Channa striata). This research seeks to identify snakehead diversity from isolated Inland waters in Sumatra, i.e., Kampar River (SK), Merang River (SM), Cala Lake (DC), and Lampam Floodplain (RL). Channa striata samples were collected from inland waters and cultivated in Aquaculture laboratory. Cytochrome b gene was used for genetic characterization. Growth protein was analyzed using Enzyme-Linked Immunosorbent Assays (ELISA). We collected DNA from four samples at each site. The growth performance of cultivated snakehead fish was also observed. Five hundred post-juvenile snakehead fish from four populations were cultivated for 45-days with five repetitions. Each population had 12 snakehead fish tested for GH protein. Data were statistically tested using ANOVA, maximum likelihood phylogenetic tree analysis, linear regression, and Pearson correlation. The results showed four clusters of snakehead fish in the phylogenetic tree. The DC population had the highest significant value of the daily length growth rate (7.5±0.2 %). The GH protein-growth relationship was low (0.014-0.083). The SM snakehead fish population had the highest concentration of GH protein (1.77±0.11 pg μl−1) and had distinct cyt.b gene clusters from other populations, making it a potential candidate for future aquaculture strain development.

Study on Pasir Lobster Enlargement (Panulirus homarus) to Improve Cultivation Productivity with Keong Bakau (Telescopium telescopium)

Abstract The potential of lobster in Indonesia is very high, the demand for lobster continues to increase every year, while the supply still utilizes the catch of fishermen. Lobster utilization in Indonesia is still low, therefore there must be sustainable cultivation in order to increase the quantity and quality of lobsters in Indonesia. One way to increase lobster enlargement is by feeding Keong Bakau. The purpose of this study is to determine and improve Lobster Pasir enlargement, including enlargement management, water quality management, and feed management with Keong Bakau. The study was conducted at the Lombok Marine Aquaculture Center, in Indonesia. The method used is a descriptive method with a quantitative approach. The feed used was Keong Bakau. The survival rate (SR) value reached 100%, the specific growth rate (SGR) value was 0.002%, and the FCR value was 23.82. The amount of feed given is sufficient for the needs of the lobster, the Keong Bakau used has chitosan which can help support the survival of the lobster. The average results of water quality include temperature (28.06oC), pH (7.07), DO (7.34 mg/l), Salinity (32.9 ppt), Turbidity (2.66 m), Phosphate (0.175 mg/l), Nitrite (0.002 mg/l), Nitrate (0.02 mg/l), and Ammonia (0.055 mg/l). DO values were slightly different from the optimal range due to the reduced intensity of vessels passing through the KJA. Keong Bakau has calcium which plays an important role in the formation of the exoskeleton in lobsters after the molting process.

The influence of different stocking density on growth rate and survival rate koi larvae (Cyprinus carpio)

Abstract Stocking density has an important role in the survival and growth of fish larvae. The purpose of this study was to determine the optimal stocking density level for larval rearing with improved feed. Tubifex sp. which has a high protein content of about 57% and fat as much as 13%. The method used was the experimental method with a completely randomized design (CRD) on 4 different treatments of stocking density with 3 replications. The treatments given were P0/Control (1 individual/L), P1 (2 individuals/L), P2 (3 individuals/L), and P3 (4 individuals/L) maintained for 49 days. The results obtained during the study were the growth rate values of P0 (0.021 gram/day), P1 (0.017 gram/day), P2 (0.016 gram/day), and P3 (0.017 gram/day). The survival rates are P0 (90.00%), P1 (91.00%), P2 (90.33%), and P3 (87.50%). Absolute length values P0 (1.94cm ), P1 (1.70cm ), P2 (1.70cm), and P3 (1.77 cm) The quality of the water obtained is that the temperature ranges from 26–29, the pH is 6.8–8.1, and the DO is 5–6. The results showed that different stocking densities had no significant effect (p &gt; 0.05) on the survival and growth rate of koi fish.

Kinetics studies and effect of the process parameters on the biodegradation of methyl orange dye

The biodegradation of methyl orange dye using Stenotrophomonas maltophilia (HE963840.1) bacteria was studied. The optimization of the biodegradation process has been performed using central composite design (CCD) of response surface methodology (RSM) with respect to three parameters namely temperature, initial dye concentration and inoculum dose. The response is best described by the second order polynomial with R2 value of 0.99. The optimized values of the process parameters were empirically checked and the model equation of the RSM was found statistically significant. The errors between experimental and model predicted results were found to be less than 8 %. The maximum dye removal efficiency was found as 86.5 ± 0.1 %. The growth kinetics of the bacteria was also studied and it is best described by Andrew-Haldane model. The values of kinetic parameters maximum specific growth rate (μmax), inhibition constant (KI) and saturation constant (KS) were found as 0.032 h−1, 156 mg/L and 78 mg/L respectively.