Average Hatching Rate Research Articles

Effects of environmentally relevant polystyrene microplastics and cadmium on the development and reproduction of rare minnow (Gobiocypris rarus)

Microplastic pollution is widespread in the natural environment, and its enrichment, inherent adsorbability, and toxicity are key concerns in society. However, few studies of the effects of microplastic toxicity on the reproduction of fish have been reported. In this study, we investigated the effects of exposure to environmentally relevant concentrations of polystyrene microplastics (PS) and cadmium (Cd) alone and in combination for 28 days on the gonad development and reproduction of rare minnow (Gobiocypris rarus). Decreased condition factor, number of spawning events, number of eggs per spawning, and average hatching rate were detected in fish in the treatment groups. These changes were likely due to long-term oxidative stress and inflammation, which inhibited the development of gonads and further affected the reproduction function of rare minnow. The effects of treatment on oxidative stress, inflammation, and expression of genes related to gonad development differed between female and male fish in the treatment groups. PS alone exposure resulted in a significant reduction in the number of eggs per spawning and average hatching rate, but these effects were not observed in the Cd and PS + Cd groups. These results provide new insights into the ecotoxicological effects of microplastics in the natural environment.

Study of the Biology of the Cochineal Scale Insect, Dactylopius opuntiae

Alhousa, W., A.N. Basheer and Z. El-Naser. 2024. Study of the Biology of the Cochineal Scale Insect, Dactylopius opuntiae. Arab Journal of Plant Protection, 42(2): 143-148. https://doi.org/10.22268/AJPP-001240 Prickly pear cochineal Dactylopius opuntiae (Cockerell) is one of the most important pests of prickly pear Opuntia ficus-indica in different regions of the world. This study was conducted with the aim of investigating the biology of the insect on the Indian prickly pear plant. The work was carried out during the 2021 season, using a random design. Samples were collected from Qatana, Syria, and the biology of the insect was studied within a rearing room under controlled conditions (temperature 25±1°C, relative humidity 45±10%). The incubation period was evaluated in a cohort of 100 eggs and the life cycle was described from a cohort of 150 individuals. Individual females were used as experimental unit (n=40 females) to determine insect fecundity. The average egg laying period was 20.76±0.77 minutes, and the average period of the first nymph was 12.66±0.53 days in females, and 14.03±0.62 days in males, and the second nymph was 25.16±2.42 days for females, and 8.72±1.67 days for males. The average period for pre-pupal and pupal stage of males was 12.9±1.63 days, and the average period of one generation from egg laying until the appearance of the adult insect was 85.85±2.09 days for females, and 56.68±0.98 days for males. Average Fertility was 226.75 eggs/female, with daily egg laying average of 17.9±0.63 eggs/female. The maximum daily fertility average was 16.6±0.35 eggs, and the average hatching rate was 87.86±3.92%. Whereas, the average egg mortality rate ranged between 21.05 and 22.05% in the reptilian stage. Keywords: Biology, prickly pear, egg incubation, nymph, fertility.

Vaname Shrimp (Litopenaus Vannamei) Hatchery Technique At CV. Manunggal 23, Serang District, Banten

Improper shrimp hatchery can have an impact on the low level of fry quality so that fry production results also decrease. Therefore, quality vannamei shrimp hatcheries must be handled appropriately in accordance with standard operating procedures that have been implemented so that they are marketable. So it is necessary to study more deeply about the vannamei shrimp hatchery, especially the vannamei shrimp hatchery technique. The purpose of this study is to find out a number of things including: Operational Standards for Vanname Shrimp Hatchery; Gonad maturity performance; and Post-harvest activities of vanname shrimp hatchery. The shrimp hatchery technique uses analysis by calculating the Fertilization Rate (HR) and Hatching Rate (HR). Based on the results of the study it was found that: 1). The technical aspects of the CV Manunggal 23 shrimp hatchery in general are in accordance with the standard procedures referred to. 2). The broodstock productivity performance at CV Manunggal 23 has a good rate with an average HR of 75.83% and FR of 62% within 3 weeks. 3). Water Quality in CV. Manunggal 23 achieved optimal numbers with an average temperature of 27-28°C, pH 8, DO 5.5-5.6 mg/L, and Salinity 32-33 ppt within 3 weeks.

The Tiger Grouper Hatchery Techniques In The Lampung Marine Aquaculture Centre, Indonesia

The tiger grouper (Epinephelus fuscoguttatus) exhibits characteristics ideal for cultivation due to its rapid growth rate and ability to be mass produced to satisfy market demand. The aim of this study is to implement the Tiger Grouper Hatchery Technique and measure the Fecundity, Fertilization Rate (FR), Hatching Rate (HR), and Survival Rate (SR) at the Tiger Grouper (Epinephelus fuscoguttatus) Hatchery located at Balai Besar Lampung Mariculture Fisheries. The chosen survey method allows for the collection of relevant data for the aforementioned parameters. Data can be collected through primary and secondary sources, as well as observation, literature review, and documentation. Hatchery techniques for Epinephelus fuscoguttatus, include the selection of parent fish, brood rearing, spawning, egg handling, larval rearing, harvesting, maintenance and transportation of seeds. The quantity of eggs laid was 3,292,475, with an average fertilization rate of 88.76%, an average hatching rate of 22.57%, and 350,000 larvae stocked, leading to 21,000 individuals or 6% survival ratio, measuring 1-3 cm in size.

Teknis Pengelolaan Pembenihan Ikan Mas Mantap Cyprinus carpio untuk Mendapatkan Benih Kualitas Unggul

The development of mirror carp (Cyprinus carpio) farming in Indonesia has progressed very rapidly, as can be seen by the increasing number of varieties of mirror carp produced from various regions with their respective specifications and advantages. Along with the need for carp that are more resistant to environmental changes and disease attacks, the development of the Majalaya carp variety subsequently produces Mantap carp fish that are disease-resistant, and growth in the growth segment is faster. The aim of this study was to disseminate technical information on Mantap fish carp culture to the public so that it can be used as a reference source for the community, especially for cultivators who are interested in developing this fish. In this study, primary and secondary data were collected. Based on the results of a fecundity study, one female broodstock produced 104.496 kg broodstock-1, the average percentage of egg fertilization (FR) was 89,64%, the average hatching rate (HR) was 61,37%, and the average survival rate (SR) until the size of the seed size 2-3 cm reaches 60%.

THE EFFECT OF TEMPERATURE DIFFERENCES ON HATCHING RATES OF LEKANG TURTLE (Lepidochelys olivacea) EGGS IN SEMI-NATURAL NESTS

This research was conducted on August 31, 2021 – December 7, 2021, at the UPTD KPSDKP, West Sumatra Province. The purpose of this study was to determine the effect of temperature differences on incubation time, hatching rate, and survival rate of turtle hatchlings (Lepidochelys olivacea). The method used in this study is an experiment that uses 3 trials plus 1 control, with 3 repetitions. Turtle eggs were incubated with the same depth and number of eggs with the addition of different temperatures from incandescent lamps with different powers. Then proceed with the calculation of incubation time, percentage of hatching, and survival of hatchling. Based on the results of the research, for the calculation of incubation time, the experimental unit with the shortest incubation period was produced by experimental unit B, with a temperature range of 27.5–29.5⁰C, which was 58 days. The incubation period that took the longest was the control experimental unit with an average temperature of 25⁰C, which was 65 days. For the results, the most optimal hatching rate was produced by experimental unit B, with an average hatching rate of 86%. Meanwhile, the lowest hatching rate was obtained from experimental unit C with an average hatching rate of only 53.3%. Then for the survival of the hatchlings after being quarantined for one week, all of them show the number 100%, which means that no hatchlings died during the quarantine

Study on Reproductive Behavior and Fry Nursing of Koi Carp (Cyprinus rubrofuscus) in Sunsari, Nepal

A study was conducted emphasizing, the induced breeding techniques, breeding behavior and nursery rearing of koi carp at Everest Aquaponics and fish farm, Sunsari, Nepal. The study was done in the hatchery Unit of EAFF for 36 days including 28 days of fry nursing from 15 May to 26 June. Ten set of brooders in the ratio of 1:2 was used. The average body weight of the female brooders was 910±164.722 gm and a female weighing one kilogram gives approximate 70,219.78 eggs in induce breeding method by hand stripping. The percentage of average fertilization rate was 68.6±3.58 %, the average hatching rate was 75.75 ± 5.9% and average survival of spawn was 66.88±5.84%. The size of the fry after hatching also varied between 2.3-3 mm whereas the fry growth varied from 17- 24mm and the average survivability from fry to fingerling was 88.9±1.59%. The mean final weight of the fry in the nursery tank was 1.0845±0.0353 gm and the average weight gain after 28 days of nursery rearing was 0.9315gm±0.013298gm. The average of the water quality values including temperature was 27.5°C, pH was 7.975, dissolved oxygen was 6.55 mg/L, NO3 concentration was 3.75 mg/L during nursery raising whereas the average water parameters during breeding were 26.75°C, pH of 7.995, DO of 6.25 mg/L, NO3 of 4.375. Successful koi farming can reduce the uncertainty and unavailability of fingerlings, can increase large-scale production for export, and can be a potential area to meet national needs and help increase revenue in foreign currencies. Current research will certainly pave the way for startups to launch commercial production and commercialization of Koi carp in the coming days.

Natural spawning, early development and first successful hatchery production of the bluestreak cleaner wrasse, Labroides dimidiatus (Valenciennes, 1839), with application of an inorganic fertilization method in larviculture

Bluestreak cleaner wrasse, Labroides dimidiatus, is one of the top ten most exported fish to the global trade in marine aquarium fish and a key species for reef fish diversity. However, knowledge on reproduction and early ontogeny of this species in captivity are scarce and incomplete. Daily spawning, early development and appropriate rearing condition (temperature and salinity) for the larviculture of L. dimidiatus were studied for the first time. We raised wrasse larvae by using an inorganic fertilization method to produce natural assemblages of phytoplankton and zooplankton, and compared it to the higher N: P ratio group and traditional rotifer-fed group. A single male dominated a harem of three females, spawning between late afternoon and dusk. L. dimidiatus spawned 305 times from 1 May 2011 to 30 April 2012, 86.9 ± 10.1% of which resulted in fertilized eggs. Fecundity ranged from 53 to 25,108 eggs per spawn with average hatching rate of 72.2 ± 22.6%. Fertilized eggs were spherical, buoyant and had a diameter of 0.68 ± 0.02 mm. Embryonic development lasted 19 h at 27.3 °C. Newly hatched larvae were 1.81 ± 0.06 mm in total length (LT) and had an oil globule in the ventroanterior area of the yolk sac. First feeding took places at 3 days post hatch (dph) which is marked by the widening of the gut. At 41 dph, transformation of larvae to the juvenile stage was completed at 12.60 ± 0.98 mm LT. On the scanning electron microscope observations, the fertilized egg membrane was smooth and lack surface sculpturing. The distribution density of pores was 61 pores 100 μm−2. The micropyle was circular or oval-shaped, and the diameter was 6.90–7.13 μm. Several neuromasts were found on the head and body surface of newly hatched larvae. The results showed that unicellular algae, zooplankton within the size ranges of 48–150 μm and larval survival of L. dimidiatus were all significantly (P < 0.05) higher in the fertilized treatment (maintaining the inorganic nitrogen and phosphorus concentrations of 700 μg N L−1 and 100 μg P L−1, respectively) compared with the others. These results indicated that the optimal conditions for embryo incubation and larval rearing of L. dimidiatus were combinations of temperature 27 °C and salinity 33 psu. Our results of this study may provide a keystone for further studies to determine the successful mass-scale production of juvenile L. dimidiatus.

Hatchery production of juveniles of pharaoh cuttlefish, Sepia pharaonis (Ehrenberg, 1831) from stranded eggs and sea ranching along the Thoothukudi coast

Accidentally entangled and stranded egg masses of Sepia pharaonis in fishing gears were collected from various landing centres of Thoothukudi district. The stranded egg masses were incubated, hatched and larval rearing was carried out at the Molluscan Fish Hatchery of Tuticorin Research Centre of CMFRI. The average hatching rate of S. pharaonis was 95 % for the eggs collected from the fishing nets. The size of day 1 paralarvae of S. pharaonis was 5.46±0.06 mm and reached the average size of 40.10±1.15 mm length and 9.6±0.20 g weight on day 60 with the average survival rate of 70 %. Maximum weight gain (%) was noticed between 20 – 40 days. The paralarvae of S. pharaonis fed with suitable live feeds until 50 days, after which fed with dead fish and shrimp. The juveniles were transformed as broodstock with an average length of 137.4±8.08 mm and weight of 229.7±21.54 g on 180 th day of culture. In the hatchery, the first captive spawning was witnessed on 167 th day and the eggs laid by the females ranged from 46 – 118. However, the captive bred egg masses failed to hatch out. Therefore, the hatchery technology needs to be perfected through the development of nutritionally improved broodstock diet to ensure better hatching. During the years 2016 – 2018, altogether 8400 numbers of hatchery reared 60 days old juveniles of S. pharaonis were ranched into the fishing grounds off Tuticorin coast. The biological significance of sea ranching activities to replenish the natural stocks requires further research and evaluation.

Recent advances in artificial breeding and larval rearing of silver pomfret Pampus argenteus (Euphrasen 1788) in Kuwait.

During last several years, Kuwait Institute for Scientific Research (KISR), Kuwait has been trying to develop a sustainable culture technique for silver pomfret (Pampus argenteus). This paper reports the recent research advances in the breeding and rearing of silver pomfret fry at KISR. The eggs collected from wild silver pomfret during spawning seasons of 2012 to 2015 were artificially fertilized under laboratory condition. The average hatching rates of artificially fertilized eggs collected from wild silver pomfrets were 25.6%, 44.8%, 76.7%, and 53.5.0% and average survival rates of metamorphosed fry produced from these eggs were 3.7%, 5.7%, 4.4% and 3.8% for the spawning seasons 2012, 2013, 2014, and 2015, respectively. For captive brood stocks, observation on the spawning time at hourly interval by collecting eggs from the nets set at out-flow of brood tanks showed that the spawning time for captive silver pomfret starts at the time of sunset. In 2012, two groups of captive silver pomfret broods spawned a total of 62x103 and 66x103 eggs, but the eggs were unfertilized. No captive spawning occurred during 2013 and 2014 spawning season. In 2015, captive silver pomfret broods in three tanks spawned about 653x103, 673x103 and 270x103 eggs, and in 2016, the broods in four tanks spawned about 669x103, 22x103, 3x103 and 366x103 eggs. However, from these eggs only 1,400 and 1,000 fertilized eggs were collected which produced 300 and 123 hatched larvae in July 2015 and June 2016, respectively. The larvae produced from the 2015 broods did not survive beyond 56 days of metamorphosed stage while larvae produced from 2016 captive broods survived for 9 days only. The mortality of the larvae from captive brood could be related to the poor egg or milt quality. However, efforts are continued to improve the eggs and sperm quality through proper brood management.

Effects of salinity, pH and alkalinity on hatching rate of fertilized eggs of Penaeus monodon

The fertilized eggs of “Nanhai 2” Penaeus monodon bred by our research group were incubated at the same temperature (30℃), different salinity (20, 25, 30, 35, 40), different pH (7.0, 7.5, 8.0, 8.5, 9.0) and different alkalinity (2.0 mmol/L, 2.5 mmol/L, 3.0 mmol/L, 3.5 mmol/L, 4.0 mmol/L) to explore the effects of salinity, pH and alkalinity on hatching rate of fertilized eggs of P. monodon. The results showed that the hatching rate of fertilization rate of P. monodon was closely related to salinity, and the best hatching rate was obtained when the seawater salinity was 30 with the average hatching rate was 82.60%. The hatching rate was very low when the salinity was as low as 20 or as high as 40, which was significantly lower than that of other treatments (P&lt;0.05). The hatching effect of the fertilized eggs of P. monodon was closely related to the pH value of seawater, and the slightly alkaline seawater was conducive to the normal development of the fertilized eggs. Among them, the hatching effect of the seawater pH value of 8.0 was the best, and the average hatching rate of the fertilized eggs was 80.62%. Too low or too high pH value of the seawater was not conducive to the development of the embryo, and the hatching rate of the fertilized eggs decreased in varying degrees. There was no significant correlation between the hatching effect of fertilized eggs and the change of seawater alkalinity. The average hatching rate of fertilized eggs ranged from 78.65% to 83.12% in the alkalinity range of 2.0-4.0 mmol/L.

Intragenus F1-hybrids of African weakly electric fish (Mormyridae: Campylomormyrus tamandua \u2642\u2009\xd7\u2009C. compressirostris \u2640) are fertile

Hybridization is widespread in fish and constitutes an important mechanism in fish speciation. There is, however, little knowledge about hybridization in mormyrids. F1-interspecies hybrids between Campylomormyrus tamandua ♂ × C. compressirostris ♀ were investigated concerning: (1) fertility; (2) survival of F2-fish and (3) new gene combinations in the F2-generation concerning the structure of the electric organ and features of the electric organ discharge. These F1-hybrids achieved sexual maturity at about 12–13.5 cm total length. A breeding group comprising six males and 13 females spawned 28 times naturally proving these F1-fish to be fertile. On average 228 eggs were spawned, the average fertilization rate was 47.8%. Eggs started to hatch 70–72 h after fertilization, average hatching rate was 95.6%. Average mortality rate during embryonic development amounted to 2.3%. Average malformation rate during the free embryonic stage was 27.7%. Exogenous feeding started on day 11. In total, we raised 353 normally developed larvae all of which died consecutively, the oldest specimen reaching an age of 5 months. During survival, the activities of the larval and adult electric organs were recorded and the structure of the adult electric organ was investigated histologically.

Lecithin-enriched Artemia combined with inert diet and its effects on reproduction and digestive enzymes of Aequidens rivulatus

The present study investigated the effects of soybean lecithin bioencapsulated in adult Artemia franciscana and unenriched Artemia in combination with an inert diet on digestive enzymes activity and reproductive performance in Aequidens rivulatus (green terror cichlid). Eight hundred and ten fish (3.1 ± 0.2 g) were randomly allotted into glass tank (80 L) and assigned to ten dietary treatments with 5 different levels (0, 25, 50, 75, and 100%) of either lecithin-enriched Artemia (EA) or unenriched Artemia (UA) over a period of 90 days. The amount of total polar lipid increased from 39.2% in the unenriched Artemia to 43.7% in the lecithin-enriched Artemia (P < .05). The fish fed with 50% EA had higher total weight, and total length compared with other groups (P < .05). The peculiar functions of total alkaline proteases, α-amylase, and lipase in green terror increased in the groups fed with lecithin-enriched Artemia, compared to the un-enriched groups (P < .05). The highest total alkaline proteases activity was observed in the fish fed with 75% EA treatment. In comparison to the other groups, fish fed 100 and 0% levels of Artemia replacement had significantly highest and lowest α-amylase activity values, respectively. Concerning reproductive performance, the highest average fecundity, egg diameter, egg weight, fertilization, hatching, and larval survival rates, as well as the lowest time between two spawning episodes, were obtained in fish fed 50% EA. In conclusion, this feeding strategy is advisable for a proper nutritional management of broodfish of green terror cichlid.

Year‐round natural spawning, early development, and the effects of temperature, salinity and prey density on captive ornate gobyIstigobius ornatus(Rüppell, 1830) larval survival

Natural spawning, early development and larviculture of the ornate goby Istigobius ornatus in captivity were studied for the first time. I. ornatus spawned 46 times from 31 October 2013 to 31 October 2014. Fecundity ranged from 246 to 10,214 eggs per clutch, with an average hatching rate of 77.8% ± 9.9% (M ± SEM). Fertilized eggs (1.31–1.54 × 0.46–0.50 mm in diameter) were adhesive demersal and oval-shaped. Embryonic development lasted 84 hr at 27.5 ± 0.5°C. Newly hatched larvae [2.12 ± 0.04 mm in total length (TL)] transformed to the juvenile stage completely when TL was 7.79 mm. Effects of different water temperatures (24, 28 and 32°C) and salinities (10, 15, 20, 25, 30, 35 and 40 g/L) on per cent survivals (%) and survival activity indices (SAIs) were tested. Survival was not significantly different under different temperatures; SAIs was significantly higher at 28°C. Larvae showed the significantly higher survival and SAIs at salinities 10–30 g/L than at 35 and 40 g/L. Effect of different prey densities on survival was significantly higher in 7 days post hatch larvae fed 20 and 30 rotifers/ml. These findings could guide future programs in captive breeding technology development and commercial production of other marine ornamental gobies.

English

This study was conducted to characterize flock size, composition, productivity, motivational drivers, and breed selection criteria in village chicken production systems of lowlands, midlands, and highlands of Ethiopia. Data were collected at 360 rural households of which 120 were from lowland, 160 midland, and 80 highlands. A standardized questionnaire was used to collect the data using person to person interview method. Data were analyzed using the various statistical procedures of statistical analysis system (SAS) version 9.2. Higher flock size and productivity of chicken were obtained for midlands than the other agro-ecologies. The average flock size per household was 16.6. The average age at sexual maturity of hens was 7 months. Average number of egg production was 43 eggs per hen per year. Average hatching rate was in the range of 76 to 82%. Mortality occurred in the range of 27 to 39%. Although, village chicken has diverse use in Ethiopian rural community, the main motivations to keep village chicken were egg production followed by income generation. Eggs were mainly used for hatching, home consumption, and to generate a daily disposable income. The three most important breed selection criteria were egg production, morphometric characteristics, and mothering ability. Findings from this study can support the design of agro-ecology based breeding strategies aiming to improve native chicken production, productivity, and enhance their economic contributions to the farmers. Key words: Ethiopian native chicken, breed selection criteria, flock productivity, motivational drivers.

Life cycle of the southern cattle tick, Rhipicephalus (Boophilus) microplus Canestrini 1888 (Acari: Ixodidae) under laboratory conditions

The southern cattle tick, Rhipicephalus (Boophilus) microplus is one of the most important tick species affecting bovine wealth worldwide. Three uninterrupted generations of this species were observed under laboratory conditions (28±3 oC and 80±5% R.H.) using rabbit hosts. The average life cycle was determined as 65±8 days. Adult feeding period averaged 7.1±1.24 days. Pre-oviposition and oviposition periods averaged 4.1±1.3 days and 8.6±0.85 days, respectively. Pre-hatching periods averaged 21.03±2.99 days. Larval free-living and feeding to moulting periods averaged 3.5±0.75 days and 7.9±0.69 days, respectively. Nymphal feeding to moulting periods averaged 10.9±1.38 days. Weights of unfed and fed females averaged 1.26±0.29 mg and 120.32±45.6 mg, respectively and produced egg masses with average weights of 29.5±9.03 mg. Number of eggs per female averaged 1455.3±434.5 eggs with peak oviposition on the 3rd day. Average hatching rate was 83.5±2.94%, and the reproduction efficiency index averaged at 12.79±2.85. The conversion efficiency index averaged at 0.26±0.05 and the reproduction fitness index averaged at 10.68±2.4. Tick recovery rate averaged at 4.7%. A strong linear relationship was found between weights of engorged females and weights of egg masses (r = 0.83) and also between weights of engorged females and number of eggs laid (r = 0.82). This work aims to describe temporal and quantitative biological facts of R. (B.) microplus life cycles. Few studies have discussed R. (B.) microplus biology in quantitative terms, and these data can be useful in designing control plans or in epidemiological studies under laboratory conditions.

The Effect of Habitat Size on Huanren Brown Frog (Rana huanrensis) Larvae's Growth Rate in Mt. Surak

This study was executed to know the effect of the habitat size on huanren brown frog (Rana huanrensis) larvae’s growth. We’ve conducted the study on Mt. Surak in Sanggye-dong, Nowon-gu, Seoul. Our study site was discriminated the huanren brown frog larvae’s habitat into the three different areas, such as small area (S1, 3.91 m²), middle area (S2, 4.42 m²), and large area (S3, 38.37m²) in the same water channel. We measured two times per a week the 15 huanren brown frog larvae’s body length, and developmental stages (foreleg, hind leg, tail length) including the environmental factors (humidity, air temperature and water temperature) of the study site from March 30 to June 28 in 2016. The only hatching rate was measured for the three egg sacs at the S2 study site. We found that the average hatching rate was 76.84 ± 18.23 (%) at S2. Generally, because of less precipitation during our study periods, all habitat areas for our study site were gradually decreased. The middle area, S2, was not reduced, the small area, S1, was reduced more than a fourth, and the largest area, S3, was drastically reduced more than half from initial area. There was no statistically difference among the three study sites for the three environmental factors (average humidity, average air temperature, and average water temperature) by F-test, but there were significant difference among the three site for the larvae’s body length (F-test p< 0.05). Therefore, the larger of habitat areas, the larger of the larvae length as well as the faster of the larvae’s developmental stages. When we measured the body lengths of immature huanren brown frogs, the immature frog of S1 was smallest, the immature frog of S3 was middle lenght, and the immature frog of S2 was largest. There were statistically different among the three study sites for the immature huanren brown frogs (F-test, p< 0.05). Because the S2 study site was relatively stable without rarely changing the study area, it meant that huanren brown frog was sensitive to habitat areas. Based on the results of this study, if we study on the effect of the altitude on the growth rate of huanren brown frog, it must be helpful in understanding the habitat environment of the population of huanren brown frog.

Gonadal maturation, fecundity and hatching performance of wild caught tiger shrimp Penaeus monodon using unilateral eyestalk ablation in captivity

In this study, the effects of eyestalk ablation on maturation, moulting, spawning and hatching rate of wild caught Penaeus monodon were investigated. Twenty males (M) and 30 eyestalk–ablated and 30 non–ablated females (F), all individually marked (M: F=1:3) were stocked into two 15–ton capacity (each) maturation tank. All the ablated females moulted in 7.92±0.24 (mean±standard error) days, and first spawning occurred 3.2±0.20 days following eyestalk ablation. While twenty-five ablated females spawned, producing an average of 296,160±26,589 eggs, only eight non–ablated females spawned, producing an average of 195,462±20,565 eggs during the investigation period of 120 days. A significant positive correlation between fecundity and female body weight (P&lt;0.05; P&lt;0.001) was observed. Throughout the experiment, the average number of spawning per female was 1.8±0.14 for ablated and one for non–ablated females. Multiple spawning (up to three times) occurred within the same moulting cycle in ablated females. Among the ablated P. monodon females, 36% spawn once, 48% second time, and 16% third time. The average fertility rate of the eggs was high, ranging between 80 and 90% in non-ablated females, while in ablated females; the range was between 72 and 88% and differ significantly (p&lt;0.05) ablated and non ablated females. Average hatching rate ranges between 70 and 80% for ablated and 75 and 82% for non-ablated females (p&lt;0.05). From eggs to nauplii production per female was 167,838 for ablated and 127,500for non–ablated females. This study indicates that eyestalk ablation and environmental condition were important inducing tools for re-maturation of spent P. monodon that continued supply of seed stock for effective commercial shrimp farming.J. Bangladesh Agril. Univ. 13(2): 315-322, December 2015

Artificial Rearing of Endemic Red-tailed BarbHypselobarbus kurali: A First Report

AbstractHypselobarbus kurali, a freshwater ray-finned fish (class Actinopterigii, order Cyprinidae), inhabits large streams and rivers of South Western Ghats of Kerala, India. The present work aims to create a breakthrough in the captive breeding technology of H. kurali and thereby successfully accomplish the goal of restocking resources. While both induced and artificial breeding were performed, the success rate for induced breeding was negligible when compared with that of artificial breeding. Artificial breeding was successfully carried out in the laboratory by dry stripping berried females (weight, 20–250 g; length, 25–28 cm) and matured milting males (weight, 180–200 g; length, 20–25 cm). Fertilized eggs were incubated in filtered source water (collected from the study site [Kulathupuzha region, Kallada River, Kollam district, Kerala]), at a temperature of 22–25°C and pH 7.5–7.8. The rate of fertilization was 92%, and the average hatching rate was 83.5%. The eggs hatched by 48 h after fertilization. ...

Survival ofCoelaenomenodera lameensis(Coleoptera: Chrysomelidae) in Relation to the Physical Characteristics of Different Oil Palm (Elaeissp.) Breeding Populations

The edibility of different Elaeis sp. breeding populations present in Benin was tested for the leaf miner Coelaenomenodera lameensis Berti (Coleoptera: Chrysomelidae), a major oil palm pest in Africa. Experiments carried out in sleeves revealed the oviposition capacities of females and the mortality rates for the different developmental stages by comparing the populations found on two breeding populations of Elaeis oleifera (HBK) Cortes, four of Elaeis guineensis Jacquin and four (E. guineensis × E. oleifera) × E. guineensis backcrosses. Females laid their eggs similarly on all breeding populations, with a preference for the E. guineensis La Mé origin. The average hatching rate reached 80% for the La Mé origin as opposed to 28% for the Deli origin. The mortality rates for the larval instars were greater on E. oleifera, on certain backcrosses and on the Deli origin of E. guineensis. Development at the second- and third- larval instars was the most affected, with a mortality rate of three to five times greater than that seen on La Mé. Epidermis and cuticle measurements indicated which breeding populations were suitable or unsuitable for the development of C. lameensis. E. guineensis, with its thin epidermis (12 µm) and cuticle (2 µm), proved to be highly susceptible to C. lameensis attacks. On the other hand, E. oleifera, which is very resistant, exhibited a thicker epidermis (17 µm) and cuticle (4 µm). The breeding populations were thus classified according to the positive or negative influence they exerted on the insect’s egg laying and feeding.RÉSUMÉ. La comestibilité de différents matériels végétaux d’Elaeis sp. présents au Bénin est testée pour Coelaenomenodera lameensis Berti (Coleoptera: Chrysomelidae), important ravageur du palmier à huile en Afrique. Des expérimentations en manchons ont permis de déterminer les capacités d’oviposition des femelles et les taux de mortalité des différents stades de développement (œufs, larves, nymphes et adultes) en comparant les populations observées sur deux origines d’Elaeis oleifera (HBK) Cortes, quatre origines d’Elaeis guineensis Jacquin et quatre Backcross (E. guineensis × E. oleifera) × E. guineensis. Les femelles pondent indifféremment sur tous les types de matériel végétal avec une préférence pour l’origine La Mé d’E. guineensis. Le taux moyen d’éclosion atteint 80% pour l’origine La Mé contre 28% pour l’origine Deli. Le taux de mortalité des stades larvaires est plus important sur E. oleifera, sur certains Backcross et sur l’origine Deli d’E. guineensis. Le développement des deuxième et troisième stades larvaires sont les plus affectés avec un taux de mortalité 3 à 5 fois supérieur à celui observé sur La Mé. Des mesures d’épiderme et de cuticule mettent en évidence l’existence de matériel végétal favorable ou défavorable au développement de C. lameensis. E. guineensis dont l’épiderme (12 µm) et la cuticule (2 µm) sont peu épais se révèle être très sensible aux attaques de C. lameensis. Au contraire, E. oleifera présente un épiderme (17 µm) et une cuticule (4 µm) plus épais et est très résistants. Le matériel végétal est ainsi classé suivant l’influence positive ou négative qu’ils exercent sur la ponte et l’alimentation des insectes.