Effects of Water Temperature on Growth Criteria of Fingerlings of Grass Carp, Ctenopharyngodon idella (Valenciennes, 1884)

The current experiment was conducted in the Fish Laboratory of Aquaculture Unit, College of Agriculture, University of Basrah from 28th January to 19th April 2021. Growth criteria of grass carp Ctenopharyngodon idella were investigated using four water temperatures (15, 20, 25 and 30 oC). Grass carp fingerlings (4.92 g) were brought from earthen ponds of the Aquaculture Unit in Al-Hartha Station for Agricultural Researches, North Basrah. The results indicated that the highest final weight (7.96 g) was reached by fishes at 15 0C, while the lowest final weight (7.22 g) was at 30 0C. Weight increments for fishes were 3.02, 2.97, 2.76 and 2.22 g for water temperatures of 15, 20, 25 and 30 0C, respectively. Fishes had the highest daily growth rate (0.0425 g/day) at 15 0C and the lowest (0.0312 g/day) at 30 0C. Fishes at 20 0C had the best feed conversion rate of 4.03, while fishes at 30 0C had the worst feed conversion rate of 5.29. It can be concluded that the best growth criteria were obtained from fishes at 15 0C and 20 0C, while the worst was observed at 30 0C.

Supplementation of Gamal leaves flour (Gliricidia sepium) in commercial feed on the growth of Nirwana tilapia (Oreochromis niloticus) fingerlings

This study aimed to examine the effect of Gamal leaves flour supplementation in commercial feed on the growth of Nirwana tilapia (Oreochromis niloticus) fingerlings. The experimental design used was a non-factorial completely randomized design consisting of four treatments and four replications. The treatments studied included commercial feed without supplementation of Gamal leaves flour as a control (P0), commercial feed with supplementation of Gamal leaves flour 10% kg−1 feed (P1), commercial feed with supplementation of Gamal leaves flour 15% kg−1 feed (P2), and commercial feed with supplementation of Gamal leaves flour 20% kg−1 feed (P3). Nirwana tilapia fingerlings were stocked at a density of 1 fish L−1. Nirwana tilapia fingerlings size ranges from 2-3 cm. Nirwana tilapia fingerlings maintenance period lasts for 40 days. The Annova test showed that the treatment gave a significant effect on the weight gain, length gain, daily growth rate, and feed conversion ratio (P < 0,05), but did not give a significant effect on the survival rate of Nirwana tilapia fingerlings (P > 0,05). The best dose to increase the growth of Nirwana tilapia fingerlings was commercial feed with supplementation of Gamal leaves flour 10% kg−1 feed.

Growth of Goramy (Osphronemus goramy Lac 1801) Monoculture and Polyculture with Nilem (Osteochilus hasselti C.V)

This research was conducted to determine the optimal density of gorami (Osphronemus goramy Lac 1801) and nilem (Osteochilus hasselti C.V) polyculture with varios nilem density. The research are carried out in the maintenance pool of the Kawungsari Fish Farmers Group, Kertayasa Village, Pangandaran Regency, Indonesia. The research method used is an experimental method with 4 treatments and 4 replications using Completely Randomized Design (CRD). Variation of stocking densities carried out with the ratio of gorami: nilem is 30 : 0 fish m2 -1 (control), 30:10 fish m2 -1, 30: 20 fish m2 -1 and 30: 30 fish m2 -1. The fish are kept for 40 days in a pond with an area of 6 x 8 m and a height of 1.2 m. The fish used are gorami with 6-8 cm long and nilem with 4-6 cm long, gorami fish from the PangandaranKertayasa farmer group and nilem fish come from the seed hall which triggers gorami stock and nilem (BPPSIGN) Tasikmalaya. Obtained data are done at the beginning of the study and every 10 days, namely on day 10th, 20th, 30th and 40th. The parameters observed included daily growth rate, survival rate, feed efficiency, periphyton abundance and water quality. The results showed the stocking density of 30 fish m2 -1gorami with 20 fish m2 -1nilem was the most optimal stocking density with survival rate of 93.5%, daily growth rate of 1.19%, and gorami’s feed efficiency is 32.66%. Pond water quality including temperature, pH and dissolved oxygen is still within optimum range in accordance with the Indonesian National Standard for maintenance of gorami and nilem.

Grading Effects on Growth and Size Variation of Common Carp Cyprinus carpio Cultivated in Floating Cages

The present study aimed to investigate the effect of fish grading on the growth performance of common carp Cyprinus carpio cultivated in floating cages located in the Al-Mashab River northwest of Basrah. A total of 4896 fishes were transferred from storage cages to culture cages (3×4×2 m), and distributed at a rate of 816 fishes per cage with a culture density of 34 fishes/m3 into six cages, three of which were classified into large (GL), middle (GM) and small (GS) individuals, whereas three cages were left without grading (UG). The graded and ungraded cages were chosen depending on the standard deviation for each cage. The fishes were fed for both treatments on a standardized, locally made diet. The results of the study were evaluated according to the criteria for total weight gain (WG), daily growth rate and specific growth rate. In the first grading process, significant differences (P<0.05) were recorded between graded (GL) and ungraded in final weight and specific growth rate (SGR) but not in weight gain and daily growth rate (DGR), while in the second grading, significant differences (P<0.05) were recorded between graded (GL) and ungraded in final weight and weight gain but not in SGR and DGR. At the end of the second grading period, the daily and specific growth rate of graded fishes were ranged between 3.26-4.73 g/day and 0.22-0.46%/day, respectively, while for ungraded fishes there were 2.35 g/day and 0.23%/day, respectively. The survival rate (SR) was not different very much in all treatments and ranged between 94.34 to 95.49% in small graded and ungraded fishes, respectively. The study results recommend at least two grading processes should be established during the culture season in two or three months intervals.

KINERJA PERTUMBUHAN DAN DINAMIKA KUALITAS AIR PADA BUDIDAYA ANGGUR LAUT (Caulerpa sp.) DENGAN NAUNGAN BERBEDA

Seagrapes (Caulerpa sp.) is one of the aquatic plants which tends to grow slowly according to the environmental conditions where sea grapes live. This study aims to determine the growth performance of sea grapes given different shelters. The method used in this study was three treatments, each treatment was repeated three times, with differences in the shade (P1 = paranet), (P2 = without roof), and (P3 = coconut leaves). Data analysis used a non-factorial completely randomized design (CRD). The results of this study are at absolute weights (P1 =1163.3 ± 260a g), (P2 = 210 ± 79.3b g), (P3 = 922 ± 199.5a g), absolute length (P1 = 5.75 ± 1.74a cm), (P2 = 0.59 ± 0 , 07b cm), (P3 = 4.82 ± 0.22a cm), daily growth rate (4.40 ± 0.1a %), (3.76 ± 0.09b %), (4.29 ± 0.09a) and the number of ramuli (P1 = 56.2 ± 21.3a), (P2 = 19.5 ± 2.3b), (P3 = 46.3 ± 3.1a). The conclusion of this study each parameter (absolute weight, absolute length and number of ramuli) has a significant difference.

Survival and growth of Pangasianodon hypophthalmus cultured under controlled photoperiod

Changing in photoperiod duration may affects the physiology of nocturnal fish such as Pangasianodon hypophthalmus. A study aims to understand the effects of controlled photoperiod towards survival and growth of P. hypophthalmus has been conducted from June to August 2020. There were 3 treatments applied, namely natural photoperiod, 18 hours dark (18D), and 24 hours dark (24D) with 3 replications in each treatment. The rearing tanks used in this study were 100 L circular plastic tanks. In 24D treatment, the tanks were placed under dark colored tarp tent continuously. For the 18D treatment, the tanks were placed under dark tarp tent, but the tent was opened for 6 hours/ day (the tanks were in dark condition for 18 hours/ day), while the control tanks were positioned under natural photoperiod. P. hypophthalmus fingerlings, 6-8 cm TL and 4-5 g BW were used in this study. Thirty fishes were reared in each rearing tank, they were feed with commercial pellets, 2 times/day, at satiation. Fish survival was monitored every day, while samplings for fish growth were conducted weekly for a 8 weeks period. Results indicate that the survival of fish was 100% in each treatment applied. Fish growth, however, shown differences. The growth of fish reared in 24D and 18D was better than that of the control. By the 9th week, the fish in 24D was around 70.71g BW with 19.27 cm TL (daily growth rate 9.35%), while those of the 18D was 69.41 g BW, 18.77 cm TL and 9.29% daily growth rate. The fish reared under natural photoperiod was around 61.95 g BW with 18.19 cm TL and 7.33% of daily growth rate. Data obtained indicate that the application of longer dark is positively improve the growth of P. hypophthalmus.Keywords:Nocturnal FishLight Dark Catfish

Public Compliance With Social Distancing Measures and SARS-CoV-2 Spread

Objective We quantified the association between public compliance with social distancing measures and the spread of SARS-CoV-2 during the first wave of the epidemic (March–May 2020) in 5 states that accounted for half of the total number of COVID-19 cases in the United States. Methods We used data on mobility and number of COVID-19 cases to longitudinally estimate associations between public compliance, as measured by human mobility, and the daily reproduction number and daily growth rate during the first wave of the COVID-19 epidemic in California, Illinois, Massachusetts, New Jersey, and New York. Results The 5 states mandated social distancing directives during March 19-24, 2020, and public compliance with mandates started to decrease in mid-April 2020. As of May 31, 2020, the daily reproduction number decreased from 2.41-5.21 to 0.72-1.19, and the daily growth rate decreased from 0.22-0.77 to –0.04 to 0.05 in the 5 states. The level of public compliance, as measured by the social distancing index (SDI) and daily encounter-density change, was high at the early stage of implementation but decreased in the 5 states. The SDI was negatively associated with the daily reproduction number (regression coefficients range, –0.04 to –0.01) and the daily growth rate (from –0.009 to –0.01). The daily encounter-density change was positively associated with the daily reproduction number (regression coefficients range, 0.24 to 1.02) and the daily growth rate (from 0.05 to 0.26). Conclusions Social distancing is an effective strategy to reduce the incidence of COVID-19 and illustrates the role of public compliance with social distancing measures to achieve public health benefits.

Effect of Different Inorganic Substrates on Growth Performance of African Catfish (Clarias gariepinus, Burchell 1822) and Lettuce (Lactuca sativa L.)

Lettuce (Lactuca sativa L.) and African catfish (Clarias gariepinus) were preferred to grow in aquaponics due to their high and fast productivity growth. However, limited research was conducted on the impact on different inorganic substrates’ growth performance in aquaponics. In this study, lettuce’s growth performance was determined in four different kinds of inorganic substrates in Nutrient Film Technique (NFT) aquaponics by measuring final weight, daily growth rate, stem diameter, plant and root lengths, leaf number per plant and shoot/root ratio. Polyester fiber, rock wool, zeolite, and gravel were used as inorganic substrate materials. A constant flow rate of 0.3 L/min was maintained using with a submersible pump motor. At the end of the study, the African catfish’s feed conversion ratio was estimated to be 0.66, while the specific growth rate (SGR) was 2.3%. Total lettuce yields for polyester fiber, rock wool, zeolite and gravel were obtained as 5.072,22 kg/m2, 4.934,03 kg/m2, 6.067 kg/m2, and 5.382,64 kg/m2 respectively. There were statistically significant differences for daily growth rate between the inorganic substrates that the significantly highest values were recorded in the zeolite. The results revealed that initial plant length and shoot/root ratio were the significant factors on the growth performance for lettuce in aquaponic system tested. The best lettuce yield performance was observed in zeolite substrate but, economically available option was found as gravel for hydroponic troughs.

Can Soil pH Correction Reduce the Animal Supplementation Needs in the Critical Autumn Period in Mediterranean Montado Ecosystem?

Extensive livestock production in Mediterranean climate conditions and acidic soils requires animal feed supplementation. This occurs during the summer and, frequently, also in the autumn and winter, depending on the prevailing rainfall patterns. The purpose of this study was to evaluate the effect of dolomitic limestone application and of tree canopy on availability, quality, and floristic composition of a permanent pasture, grazed by sheep. At the end of autumn, winter, and spring of 2018/2019 and 2019/2020 pasture green and dry matter production (GM and DM, respectively), crude protein (CP), and fiber (neutral detergent fiber) were monitored in 24 sampling points. Half of these points were located in areas amended with dolomitic limestone (COR) and half in unamended areas (UCOR). In each of these, half of the sampling points were located under tree canopy (UTC) and half outside tree canopy (OTC). Pasture floristic composition was monitored in spring 2020. The results show, in autumn, a positive and significant effect (i) of soil pH amendment on pasture DM and CP daily growth rate (kg·ha−1·day−1) (+28.8% and +42.6%, respectively), and (ii) of tree canopy on pasture CP daily growth rate (+26.4%). Both factors affect pasture floristic composition. Pasture species were identified as potential bio-indicators, characteristic of each field area. These results show the practical interest of the soil pH correction to reduce the animal supplementation needs in the critical autumn period in the Mediterranean montado ecosystem.