Average Egg Diameter Research Articles

New Records of the Egg Development Phase of Varuna litterata in the Lower Serayu River, Central Java

One of the Brachyura crabs found in the lower reaches of the Serayu River is Varuna litterata, also known as the "herring bow crab". This crab usually inhabits shallow tidal areas and hides under rocks, logs, or dead leaves. It is a highly adapted crab found in a wide range of salinities. V. litterata is also a fishery product consumed in Thailand, the Philippines, and Indonesia. This research was conducted in the Lower Serayu River, Central Java, which consists of three observation stations, namely: 1) the first station is located above the dam with fresh water, 2) the second station is below the dam with fresh water properties and 3) the third station is downstream (estuary) of the Serayu River with brackish water. This research was conducted for four months, from October 2023 to January 2024. This study aimed to determine the level of egg development in V. litterata. The results showed that V. litterata experienced four stages in egg development and then hatched into zoea. At the initial development stage, V. litterata eggs will be purple; in the second stage, the eggs will turn reddish; in the third development stage, the eggs will turn orange to brownish; and in the fourth stage, the eggs will develop and become black. V. litterata that will spawn will migrate to brackish waters to hatch their eggs. V. litterata produces 20,708 - 85,886 eggs with an average egg diameter of 0.440 - 0.466 mm.

Embryonic and Larval Development of Hybrid Giant Grouper × Potato Grouper (PGGG) Male and Tiger Grouper (TG) Female

This study aims to collect data and information of embryonic and larval development on the cross breeding between hybrid Giant Grouper × Potato Grouper (PGGG) male and Tiger Grouper (TG). The body weight of broodfish above 20 kg for male and 4 kg for female. Broodstock selection of Hybrid Giant Grouper × Potato Grouper (PGGG) male can usually be stripped by applying gentle pressure to the abdomen between the pelvic and the vent fins. Induced spawning by mixing sperm and eggs manually. Signs of a mature gonadal female are characterized by an enlarged abdomen, slow movements and tend to tilt, the genital opening increasingly swollen and red in colour. The results show that spawning at night 23.30 with an average egg diameter of 0.85±0.09 mm. The eggs hatch at 15.45 or 16 hours 15 minutes. Hatching rate being 24%-32%.

Reproduction of Carijoa riisei (Cnidaria: Octocorallia) in the Panamanian tropical eastern Pacific

Octocorals are the main component of rocky walls in the Panamanian tropical eastern Pacific (TEP), providing shelter and substrate for diverse marine invertebrates and demersal fishes. Despite their ecological importance, many essential biological traits of these corals remain undescribed. Like some cnidarians, octocorals may be related to bioinvasion. One emerging risk is the rise of the Indo-Pacific invasive octocoral Carijoa riisei, which overgrows other soft corals, competing for food and space and promoting the emergence of diseases. Considering the potential risk to native octocorals, we investigated the reproductive seasonality of C. riisei at 15 m depth every month for one year in the Gulf of Panama (Las Perlas Archipelago), an octocoral diversity hotspot with seasonal upwelling. Carijoa riisei showed an average fecundity (percentage of polyps with eggs sampled throughout the year from only female colonies) of 53% (SE 0.03%) with no seasonality. Carijoa riisei produced eggs continuously with overlapping generations, with an average of 23 (1–107; SE 0.75) eggs per fertile polyp and an average egg diameter of 0.12 (0.10–0.64; SE 0.0008) mm. The number of eggs inside the gastrovascular cavity was higher during the upwelling. However, the size and proportion of large eggs were greater towards the end of the upwelling season, with a drastic decrease from 30% to 2% at its end. Our results over a one-year sampling period show that in the Panamanian TEP, C. riisei reproduces continuously, seemingly energized by higher nutrient levels present during upwelling. This, along with its rapid growth rate, makes this species a formidable competitor for native species. Thus, we encourage future monitoring of these populations.

PERKEMBANGAN EMBRIO DAN PERFORMA AWAL LARVA IKAN TAWES (Barbonymus gonionotus)

The research was carried out from November 2021 to January 2022, and the trial period from November 1 to November 12, 2021 at the Germplasm Research Installation for Freshwater Fisheries in Cijeruk, Bogor, West Java. This study aims to determine the embryonic development and early performance of Tawes fish (Barbonymus gonionotus) larvae. This experimental study used 2 male tawes broodstock, 2 female brood fish, and anesthetic drugs. Parameters observed included observation of embryos and early performance of Tawes larvae. The embryo data were analyzed in a qualitative descriptive manner with pictures of each phase of egg development and followed by data on egg hatching time. The results showed that the early embryonic development of Tawes fish generally includes the stages of egg division, morula, blastula, gastrula, segmentation and hatching. The initial performance of Tawes larvae reared at 28oC showed abnormality values ​​of Tawes fish of 5.78±1.52%, average egg diameter of 1.02±0.04 mm, average initial length of larvae of 7.28±0.55 mm.

Bafra Balık Gölleri’nden Tatlı Gölü ve Gıcı Gölü’ndeki Tatlısu Istakozu (Astacus leptodactylus Eschscholtz, 1823)’nun Bazı Popülasyon Parametrelerinin Belirlenmesi

In this study, determination of the morphometric parameters and egg fecundity freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823), measurement and comparing of were aimed in Tatlı and Gıcı Lakes from Bafra Fish Lakes in Samsun, Turkey. The research was carried out between November 2018 and October 2019 by monthly catching of freshwater crayfish using fyke net at determined stations. While 105 of 242 freshwater crayfish from Tatlı Lake were female and 137 were male, 87 of 216 freshwater crayfish from Gıcı Lake were female and 129 were male and the difference between the sexes was not significant. The average total length and average weight of freshwater crayfish from Tatlı Lake were 10.27±0.09 cm and 33.76±0.88 g, respectively. In Gıcı Lake, the average total length and average weight of freshwater crayfish were 10.44±0.41 cm and 37.15±1.91 g, respectively. A strong positive linear relationship was found between length and weight of freshwater crayfish in Tatlı Lake and Gıcı Lake. However, the claw length and claw width of the male freshwater crayfish were greater. The average number of individual eggs, the average total egg weight, the average unit egg weight and the average egg diameter of the sampled egged crayfish in Tatlı Lake were 241.24±11.94, 3.22±0.17 g, 0.013±0.001 g and 2.61±0.02 mm, respectively. These were 245.38±15.87, 3.03±0.19 g, 0.013±0.001 g and 2.73±0.02 mm for sampled egged lobsters in Gıcı Lake, respectively. At the end of the study, it was determined that the environmental and morphometric parameters, egg fecundity of freshwater crayfish in Tatlı and Gıcı Lakes were similar between the lakes.

A Study on Some Biological Parameters of Crayfish (Astacus leptodactylus Eschscholtz, 1823) in Ulugöl, Samsun, Turkey

The study aimed to investigate some morphometric traits, length-weight relationship, meat yield, fecundity and some biochemical compositions of Astacus leptodactylus, in one of the Bafra Fish Lakes named Ulugöl, Samsun, Turkey. A total of 378 A. leptodactylus (198 female and 180 male) were examined. The average carapace length was 50.96±0.46 mm for females, 51.31±0.66 mm for males and 51.13±0.40 mm for all sampled crayfish. Abdomen length was 52.36±0.49 mm for females, 49.26±0.62 mm for males and 50.87±0.40 mm for all sampled crayfish. Live weight was between 14.38 g and 105.03 g with an average of 38.26±0.73 g. The average weight of females was less than that of males. There was a strong relationship between length and weight. The weight of crayfish with pleopodal eggs ranged from 28.24 g, to 59.50 g with an average of 41.73±1.09g. The average number of eggs per individuals was 192.90±9.94 with an average number of 4.62±0.21 per unit of live weight. The average total egg weight was 3.35±0.19 g while the average egg diameter was 2.17±0.03 mm. Abdomen meat was lower for males comparing with females. Average moisture, crude ash, crude oil and crude protein of abdomen meat were 81.27%, 1.47%, 0.81% and 16.45%, respectively.

Age, Growth and Reproduction of Neogobius melanostomus (Pallas 1814) (Perciformes: Gobiidae) in the Southern Black Sea

Round goby (Neogobius melanostomus, Pallas 1814) which belongs to Gobiidae, inhabits in the Black Sea, the Marmara Sea, the Caspian Sea and the rivers that flows into fore stated seas. The main population parameters, such as age, length, sexual composition, length-weight relationship, growth, condition factor, gonadosomatic index and reproduction of N. melanostomus were investigated from coasts of the southern Black Sea in this study. A total of 2408 individuals were sampled between July 2017 and June 2018. Results showed that average length and weight were found 14.97 cm (10.50-26.20) and 43.90 g (15.28-212.2), respectively. Sex ratio between female and male was found 1:1.77 (P>0.05). Age of samples varied between one and eight years old. The von Bertalanffy growth parameters were calculated as L∞ = 26.5 cm, k = 0.1980 year-1 and t0 = -1.3487 year for all individuals. The length-weight relationship was found as W = 0.0069 TL3.1972 for all individuals. Total mortality, natural mortality, fishing mortality, growth performance index and condition factor were calculated as 0.625, 0.479, 0.145, 2.143, and 1.66, respectively. Spawning occurs between March and May and the maximum value of gonadosomatic index reached in April. Average relative fecundity was 318.88 number/g (124.8-958.9), while average diameter of eggs was found 2025.58 µm ± 262.86 (1112.0-2703.4). This study will contribute for information gap on the species as well as provide information source for future studies.

The Maturity of Female Gonads of G2 Transgenic Mutiara Catfish (Clarias sp.)

The G2 trangsenic Mutiara catfish (Clarias sp.) (MTG) is a Mutiara catfish that is inserted with the CgGH gene (Clarias gariepinus Growth Hormone) through the transgenesis. The effect of transgenesis stimulates gonad growth of G2 transgenic Mutiara catfish (Clarias sp.) faster than non-transgenic fish. Study aimed to analyze the maturity of the gonads and the spawning ability of female G2 transgenic Mutiara catfish (Clarias sp.) to obtain superior broodstock candidates. Experimental method with completely randomized design (pair of parents used as treatment and repeated four times) for spawning was used for this study. Three pairs of parent G2 were crossed semi-artificially as treatment A (female 1 MTG G2 crossed with male 1 MTG G2), B (female 2 MTG G2 crossed with male 2 MTG G2) and C (female 3 MTG G2 crossed with male 3 MTG G2). The results showed that the performance of female G2 transgenic Mutiara catfish (Clarias sp.) (treatment A, B and C) was higher given non-transgenic with an average relative fecundity of 82,438 eggs / kg of broodstock, an average egg diameter of 1.76 mm and an average egg weight 1.75 mg. These indications suggest that GH transgenesis increases gonadal maturity. The gonad maturity profile reached the stage of complete maturity (full ripe) compared to Sangkuriang catfish (Clarias gariepinus) (immature gonads). Therefore it is necessary to compare the reproductive performance of G2 transgenic Mutiara catfish (Clarias sp.) with non-transgenic fish (Sangkuriang) as candidates for superior broodstock of catfish.

ANALYSIS OF SEA TURTLE NESTING AREA IN PANDAN ISLAND WEST SUMATRA

The research was conducted on February – March 2020 and located in Pandan Island with using survey method. The research aimed to analyze characteristic habitat of the physical and biological turtle nesting beaches, the distribution of turtle’s nests, and the microbial conditions of the turtle’s nests. The result showed that the length of beach was 1,379.4 m with average width of beach was 16.13 m. The average beach slope was 5.52 %. Substrate type dominated by sand substrate. The most abundant vegetation was ketapang tree (Terminalia catappa) and the predators discovered were monitor lizard and dog. There where 4 turtle nests were found, which was 3 nests of hawksbill turtles and 1 nest of green turtle. The average distance of nests from high tide line was 5.7 m with average distance between nest was 177.87 m. Respectively, the average of temperature, humidity, and depth of the nests were 29.58℃, 12.78%, and 53.3 cm. The average size of curve carapace length was 84.25 cm and average curve carapace width was 76.25 cm. The average number of eggs was 144 of each nest with average diameter of eggs was 3.35 cm.

LAYING AND EGG QUALITY OF QUAIL FED DIETS CONTAINING KUHOL MEAL (Pomacea canaliculata) FORTIFIED WITH DIFFERENT PHYTOBIOTICS

Phytobiotics are plant-derived products that are added to the diet of the animals. Kuhol (Pomacea canaliculata) or golden apple snail was introduced critically as food but became destructive mollusk which invaded rice fields and eventually became pest. This study was conducted to determine the quality of quail fed diets laying and eggs that contain kuhol meal fortified with various phytobiotics. Proximate analysis was performed on phytobiotics leaf and kuhol meal. Completely randomized design (CRD) was followed to analyse the gathered date on 225 twenty two days old Japanese Seattle quails distributed to five treatments. Results shows that significant differences were observed on laying efficiency, egg production, feed conversion ratio and cost of production per egg. Insignificant differences among treatment means were recorded on average egg weight, average egg diameter, average egg shell-thickness and shelled to shell-less egg ratio. In addition, an inclusion of 1.5% phytobiotics and kuhol meal in the diet, gave experimental animal different performance but did not affect to improve egg quality. Trials on some plants having comparable properties are also conducted in this study.

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.

Reproductive biology of the invasive sharpbelly, Hemiculter leucisculus (Basilewsky, 1855), from the southern Caspian Sea basin

The sharpbelly, Hemiculter leucisculus , an invasive species, has expanded its range throughout much of Asia and into the Middle East. However, little is known of its reproductive information regarding spawning pattern and season that could possibly explain its success as an invasive species. This research is the first presentation of its reproductive characteristics, which was conducted based on 235 individuals collected monthly throughout a year from Sefid River, in the southern Caspian Sea basin. Age, sex ratio, fecundity, oocytes diameter and gonado-somatic index were calculated. Regression analyses were used to find relations among fecundity and fish size, gonad weight (Wg) and age. The mature males and females were longer than 93.0 and 99.7mm in total length, respectively (+1 in age). The average egg diameter ranged from 0.4mm (April) to 1.1mm (August). Spawning took place in August, when the water temperature was 23 to 26°C. Average gonado-somatic index values for females at the beginning of the reproduction period (March) and in ripe mature spawning females (August) were 2.90% and 16.97%, respectively. The averages of absolute and relative fecundities were 19978.6 and 607.1 eggs, respectively. The absolute fecundity was significantly related to body weight, ovary weight and age. A potentially high reproductive capacity, comparatively small eggs, short time of eggs’ development, fast sexual maturation, short life span, tolerance to a wide range of environmental conditions, all promote the invasion of this invasive sharpbelly in freshwater ecosystems of the temperate climate zone.

Age, growth, sex ratio, spawning season and fecundity of Capoeta razii from Sefidroud River in the southern Caspian Sea basin

Some aspects of reproductive biology of Capoeta razii , an endemic cyprinid species from the Sefid River in the southern Caspian Sea basin, were studied by monthly sampling throughout a year. Age, growth, sex ratio, spawning season, fecundity, gonado-somatic, modified gonado-somatic and Dobriyal indices were estimated. The sex ratio (F: M) was obtained as 1.00:2.63, and the percentage of males was greater than females. The mature males and females were longer than 88 and 148 mm in total length, and 1 + and 2 + in age, respectively. The spawning of C. razii took place from late May to late August when the water temperature was between 19.7 and 22.8 ◦ C. At the beginning of the reproduction period, the average gonado-somatic index values were 10.0% ranging from 4.03% to 15.90% in ripe females. The estimated gonadal indices showed that the ripe males were ready to spawn earlier than females. The average egg diameter was 0.99±0.65, ranging from 0.2 to 2.3 mm. The averages absolute and relative fecundity were 4386±2174 and 66.3±37.8, respectively. The absolute fecundity was significantly related to body weight and gonad weight.

Reproductive Potential of Captive Rio Grande Silvery Minnow

AbstractCaptive propagation and augmentation of the Rio Grande Silvery Minnow Hybognathus amarus is necessary for continued persistence of the species until habitat can be restored. Augmentation occurs using captive fish within the first year (age 0) through age 2; however, older year‐classes (ages 3–4) have been released into the wild. We quantified fecundity and compared egg quality across four reproductive age‐classes (1–4) of hatchery‐reared Rio Grande Silvery Minnow. Batch fecundity (total number of spawned eggs) ranged from 2,029 eggs in age‐1 fish to 10,588 eggs in age‐4 fish. Standing stock of vitellogenic (i.e., yolked) oocytes remaining in ovaries after spawning increased from 988 oocytes at age 1 to 4,924 oocytes at age 4. Total fecundity (i.e., batch fecundity plus standing stock of yolked oocytes) increased from 3,017 eggs and yolked oocytes in age‐1 fish to 15,522 eggs and yolked oocytes in age‐4 fish. Of note, batch fecundity ranged from 57% to 68% across the four age‐classes indicating that over half of the total fecundity occurs in the first spawn. Average percent fertilization of eggs (63–82%) was not detectably different across the four age‐classes, while average egg diameter (4.1–5.5 mm) increased as age increased. Fecundity increased across all four reproductive age‐classes of Rio Grande Silvery Minnow, with the larger portion of total fecundity occurring in the first spawn across all age‐classes. The timing of spawning with optimal conditions in the Rio Grande is critical for survival and ultimately recruitment into the wild fish population.

Reproductive performance of asian catfish ( Hemibagrus wyckii Bleeker, 1858), a candidate species for aquaculture.

Background:Hemibagrus wyckii Bagridae is one of the important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Methods: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using Labo microscope model L-711 using software camera 3. Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.

Reproductive performance of asian catfish ( Hemibagrus wyckii Bleeker, 1858), a candidate species for aquaculture

Background: Hemibagrus wyckii Bagridae is one of the important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Method s: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using Labo microscope model L-711 using software camera 3. Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.

Reproductive performance of asian catfish (Hemibagrus wyckii Bagridae), a candidate species for aquaculture

Background: Hemibagrus wyckii Bagridae is one of the most important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Methods: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using an Olympus microscope (CX40). Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.

Reproductive biology of female Oxynoemacheilus bergianus (Actinopterygii: Cypriniformes: Nemacheilidae) from the Jajrud River, the Namak Lake basin, central Iran

Loach fishes of the genus Oxynoemacheilus , are found in Iran and adjusted countries, but their reproductive parameters are barely known. The main aim of this study was to obtain reproductive characteristics of Oxynoemacheilus bergianus (Derjavin, 1934). Sampling was carried out at monthly intervals throughout the year and 279 individuals of O. bergianus were caught from the River Jajrud in the Namak Lake basin, central Iran. Age, fecundity, oocyte diameter and Gonado-Somatic Index (GSI) were examined. Regression analyses were used to find relations between fecundity and fish size, gonad weight (Wg) and age. The average egg diameter ranged from 142.8 micrometer (August) to 513.1 micrometer (March). Spawning took place in March, when the water temperature was between 16 and 20°C. The average GSI values for females at the beginning of the reproduction period (February) and in ripe mature females (March), were 9.8% and 22.4%, respectively. The averages of absolute and relative fecundity (relative to body weight) were 2792.4 eggs (SE±692.5) and of 637.9 (SE±119.6) per gram body weight, respectively. The absolute fecundity was significantly related to body weight and ovary weight. Based on the pattern of GSI, it was concluded that this fish has a relatively prolonged active reproductive period. The present knowledge could be used in the conservation and management strategies intended to maintain the O. bergianus stock.

Application of a novel tyramine substituted hyaluronan gel for culture of mouse pre-antral follicles

Follicle culture in matrices that allow 3-D growth may better mimic in vivo conditions by preserving follicle architecture and critical granulosa-oocyte interactions.This report describes the application of a new biomaterial for in vitro follicle maturation (IVM) and the production of functionally competent oocytes. Mouse pre-antral follicle model for IVM and testing of a hylaluronan matrix. Ovaries from 12 -14 day SJLs pups were removed. Pre-antral follicles were collected by either mechanical dissection (M) or with collagenase (CL) digestion. Pre-antral follicles with 2-3 layers of granulosa cells were collected. Crosslinking of hyaluronan (HA) gel was initiated and 5-7ul drops were pipetted in to wells. Follicles were added before gelling was completed. Culture medium (25ul) was added to each well and along with an oil overlay. Follicles were cultured at 37C with 6% CO2 culture in α-MEM supplemented with 5% FBS, 100 mIU/ml FSH,10 mIU/ml LH and ITS. Final maturation was triggered with hCG (1.5 iu/ml) and EGF (5 ng/ml) after 12 days of growth. Follicles were monitored daily and medium was collected for hormone assay. Mature oocytes were inseminated with sperm and fertilization was assessed the following morning. Outcome parameters monitored were follicle morphology, survival to the end of the in vitro culture (IVC) interval, estradiol secretion,germinal vesicle breakdown, oocyte maturation to the metaphase II stage and 2-cell zygote formation following IVF insemination. Differences between treatments were analyzed using the Chi square and student T test. P value of <0.05 was considered significant. Average diameter of collagenase isolated follicles was 120.3 ± 5.4, with an average egg diameter of 61.1μm ± 2.1. Post maturation oocyte measurements for the non-HA and HA follicles were 87.9μm ± 4.4 and 86.2μm ± 6.4, respectively. Maturation rates for CL isolated follicles embedded in HA gels (75.7%) or cultured in medium alone(84.7%) were similar. A significantly lower maturation rate (59%) was obtained with mechanically isolated follicles embedded in HA gel.Therefore CL was used for subsequent experiments.Tabled 1IVM Summary DataHA GelHA GelNon-HA Gel(M)(CL)(CL)Number of Follicles Cultured122283293Ovulated COCs70144184Mature Oocytes41108155Maturation Rate (%)59 ± 0.7*75.7 ± 13.3284.7 ± 8.1Fertilization Rate (%)-88.7 ± 5.983.3 ± 10.1* Significantly different from CL. Open table in a new tab * Significantly different from CL. The HA matrix allowed continued follicle growth, oocyte maturation and resumption of meiosis. Functional competence of oocytes from HA matured follicles was confirmed by their ability to fertilize.Further testing and live birth data is needed to validate this culture model. HA is a natural matrix for cell growth and may prove especially advantageous when applied to follicles in large animal models requiring maintenance of follicular architecture over longer culture intervals.

Reproductive biology of the endemic dace Telestes karsticus Marčić and Mrakovčić, 2011 (Cyprinidae, Leuciscinae), in Croatia

This paper aims to establish how Telestes karsticus has adapted its reproductive behaviour to the hydrological conditions in Sušik Creek, which dries up in the summer. Initial data are provided on the reproductive biology of this endangered (EN) and endemic species of Croatia. Fish were collected at monthly intervals from July 2007 to July 2008 using a backpack electrofishing device. The spawning period lasts from late March to early May, confirmed by the gonadosomatic index (GSI) of males and egg diameter measurements. The value of GSI for both males and females is clearly cyclic, with only one maximum achieved in April. Sexual maturity is reached at an early age, with 50% becoming mature at total lengths longer than 41 mm (males) and 51 mm (females). Absolute fecundity of gravid females ranged from 201 to 3,188 eggs and relative fecundity was 153.6 ± 33.9 eggs per gram of body mass. Average egg diameter was determined as 1.22 ± 0.23 mm. The species is lithophilous, with eggs found in nature on gravel and among rocks. Water temperature during the spawning period ranged from 7.3°C to 13.5°C, with an average of 9.8°C. The spawning period coincides with the second peak of the 30-year-average water level in the creek, which runs dry during the summer period.