Egg Diameter Research Articles

Egg Size Scales Negatively With System Size in a Periodic Fish Species.

Optimal egg size theory implies that female organisms balance between fecundity and individual offspring investment according to their environment. Past interspecific studies suggest that fishes in large marine systems generally produce smaller eggs than those in small freshwater systems. We tested whether intraspecific egg size variation reflected a similar pattern by comparing egg size among yellow perch (Perca flavescens) populations inhabiting a range of system sizes. In 2018, 2019, and 2023, we collected yellow perch egg samples from 12 locations in systems ranging in surface area from 37 to 5,390,492 ha. First, we found that egg diameter significantly increased with maternal total length in five of eight individually tested populations. After accounting for these maternal effects, we found a significant interaction, where females inhabiting larger lakes, such as the main basins of Lakes Erie and Michigan, produced smaller eggs than those in smaller inland lakes, and the greatest differences were demonstrated among females of greater total length. This egg size variation in the largest females is consistent with interspecific egg size comparisons between marine and freshwater fishes. However, by examining a single species across vastly different environments, we were able to support theoretical expectations that maternal investment in offspring should vary with environmental conditions controlling early-life resource acquisition and competition.

Effect of Starvation and Refeeding on Gamete Quality and Fertilization in Rainbow Trout (Oncorhynchus mykiss) Broodstock

In this study, the impact of starvation and refeeding on broodstocks was observed by examining quality parameters of gametes and fertilization. While the control group fish were fed every day, the male and female members of the group were fed one week apart and placed in starvation after a week of feeding. Weight gain in the control group was the highest. The feed conversion ratio was normal in all groups (0.9-1.3%). Relative fecundity was (935±62 eggs/kg) in control group females; it was found to be (1317±241 eggs/kg) in starving females and statistically different in the groups (p < .05). The egg diameter of the group receiving intermittent feeding for a week (3.36±0.2 mm) was found to be the lowest. All spermatological parameters were similar between groups, except for sperm volume. The most sperm count was seen in the group that received one-week intermittent feeding (46.9± 20 ml). The results of fertilization with the control female in the fertilization study based on male individuals showed similarity for the male individuals of the trial group, the highest fertilization rate was seen in fertilization using the control female and control male.

Effects of dietary cholesterol on ovary development and reproductive capacity in Pacific white shrimp broodstock, Litopenaeus vannamei

Cholesterol is an important component of fresh biological baits and essential precursor to synthesize steroid hormones for crustacean. However, the cholesterol demand in Pacific white shrimp broodstock and its roles on ovary development and reproductive capacity are unknown. In the present study, female Pacific white shrimp broodstock (initial weight 51.3 ± 0.5 g) were fed with three diets contained 0.5 %, 1 % or 1.5 % cholesterol for 45 days. The results found that dietary cholesterol levels did not affect survival rate, weight gain, egg-laying number, vitellogenin content and vitellogenin receptor gene expression in the hepatopancreas. However, the hepatosomatic index, gonadosomatic index, egg diameter, vitellogenin level in the ovary and fertilized egg, C22:6n-3 (DHA) level in the fertilized egg, total protein, triglyceride and cholesterol contents were all increased in the 1.0 % and 1.5 % cholesterol groups than those in the 0.5 % cholesterol group. Moreover, compared with the 0.5 % and 1.0 % cholesterol groups, the 1.5 % cholesterol group had significantly higher gonad maturation number, mating rate, estradiol level in the hemolymph, steroid hormones synthesis related genes (HMGCR, StAR, 17βHSD and 1vMFBP) expression in the ovary and hepatopancreas. In conclusion, dietary 1.5 % cholesterol could promote ovary development and reproductive capacity in female Litopenaeus vannamei broodstock by improving nutrients accumulation and steroid hormones synthesis pathway. Our results provide guidance for design of artificial compound feed and healthy development of shrimp broodstock farm.

Observation on embryonic development of Gymnodiptychus dybowskii (Kessler, 1874) in Manas River, Xinjiang, China

To protect the germplasm resources of Gymnodiptychus dybowskii (Kessler, 1874), a species endemic to Xinjiang, the key stages of embryonic development of G. dybowskii were studied. From May to July 2021, the artificial breeding of G. dybowskii was carried out at the fish breeding station of the Kenswart Water Conservancy Project. The embryos and early larvae were obtained using temperature promotion, water stimulation, hormone induction, and dry insemination techniques. their development process was observed, and morphological characteristics of each developmental stage were recorded. The results showed that the mature oocyte was round, heavy, and light yellow, with an egg diameter of (2.32 ± 0.21) mm. The fertilized egg was slightly viscous, and the viscosity disappeared after water absorption. Under the temperature of 15.6-17.7 ℃ (16.23 ± 0.52) ℃, the embryonic development of G. dybowskii lasted for 142 h and 33 min and went through 7 stages of fertilization, cleavage, blastula, gastrula, neurula embryo, organ formation, and membrane hatching, with a total of 26 periods. The membrane broke after 2376.724 ℃·h. The embryonic development of G. dybowskii follows the rule of freshwater bony fish, but it differs from other Schizothorax species in the muscular effect period and membrane emergence mode. In addition, differences in hatching water temperature among different geographic populations lead to differences in embryo development duration and accumulated temperature, which further proves that G. dybowskii is highly adaptive to the ecological environment of its habitat water, and these characteristics together constitute its survival and reproduction strategy in the natural environment. In this study, through the artificial breeding experiment of G. dybowskii, the characteristics of its embryonic development were explored, which laid the foundation for the cultivation of unique fish seedlings, enriched the early life history data of G. dybowskii, and further provided basic data for its resource protection.

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.

Reproduction of Cernuella virgata (Da Costa, 1778) (Gastropoda: Geomitridae) in its natural environment in Southeast Turkey

ABSTRACT This study aims to investigate the reproductive characteristics of Cernuella virgata (Da Costa, 1778) from Diyarbakır, Southeast Turkey. From October 2023 to February 2024, the reproductive activities of over 300 individuals were monitored in Yeniköy Cemetery in Diyarbakır. The snails were first observed mating on 18 October 2023, after the autumn rains, with the first egg laying observed on 3 November 2023. The last mating observation occurred on 8 January 2024. A total of 225 individuals were noticed mating during this period. The number of eggs per clutch ranged from 36 to 114, with an egg hatching time between 18 and 32 days. Eggs were deposited amidst damp mosses, beneath decomposing vegetation, or on the damp soil surface. The spawning period lasts 12–13 weeks. Egg weights varied from 0.60 to 1.20 mg, and egg diameters ranged from 1.10 to 1.42 mm. Hatchling snails had shells with 1.5–2 whorls (protoconch), weighing between 1.15 and 1.72 mg on. The height of the hatchling’s shells ranged from 0.75 to 0.94 mm, and the width ranged from 1.21 to 1.38 mm. This study offers a detailed insight into the reproductive biology of C. virgata and marks the first record of the species in the region.

Assessing reproductive effects and epigenetic responses in Austrolebias charrua exposed to Roundup Transorb®: Insights from miRNA profiling and molecular interaction analysis

This study examines the effects of Roundup Transorb® (RDT) exposure on reproductive functions and ovarian miRNA expression in Austrolebias charrua. Exposure to RDT (at 0.065 or 5 mg. L−1 for 96 h) significantly disrupts fertility, evidenced by changes in fertilization rates and egg diameter. Profiling of ovarian miRNAs identified a total 205 miRNAs in A. charrua. Among these, three miRNAs were upregulated (miR-10b-5p, miR-132–3p, miR-100–5p), while ten miRNAs were downregulated (miR-499–5p, miR-375, miR-205–5p, miR-206–3p, miR-203a-3p, miR-133b-3p, miR-203b-5p, miR-184, miR-133a-3p, miR-2188–5p) compared to non-exposed fish. This study reveals that differentially expressed miRNAs are linked to molecular pathways such as steroid hormone biosynthesis, lipid and carbohydrate metabolism, bioenergetics, and antioxidant defense. It also analyzes molecular interactions between miRNAs and target genes during RDT exposure in annual killifish, providing insights into biomarkers in ecotoxicology. Moreover, it provides scope for developing environmental health assessment models based on epigenomic endpoints, supporting the protection of biodiversity and ecosystem services through the quantification of stress responses in living organisms exposed to pesticides.

The regulatory effects of water probiotic supplementation on the blood physiology, reproductive performance, and its related genes in Red Tilapia (Oreochromis niloticus X O. mossambicus)

Probiotics are becoming increasingly popular as eco-friendly alternatives in aquaculture. However, there is limited research on their impacts on the reproductive efficiency of Red Tilapia (Oreochromis niloticus x O. mossambicus) broodstock. Therefore, this experiment aimed to explore the combined effects of selective probiotics Bacillus subtilis and B. licheniformis (BSL; 1:1) added to water on blood hematology, serum metabolites, gonadal histology, reproductive performance, and reproductive associated genes in Red Tilapia broodstock. Tilapia broodfish weighing 140–160 g were stocked in four treatment groups: control (T0), and the other three groups were added different levels of BSL to the water as follows: T1 (0.01 g/m3), T2 (0.02 g/m3), and T3 (0.03 g/m3), respectively. Results indicate that BSL administration significantly improved RBCs, hemoglobin, hematocrit, MCH, and MCHC, with the highest improvement seen in the T3 group (P < 0.05). BSL added to the fish water significantly enhanced serum protein fractions (total protein, albumin, and globulins), while AST, ALT, ALP, creatinine, uric acid, and glucose were significantly diminished in a dose-dependent way (P < 0.05). Adding 0.02–0.03 g/ m3 of BSL resulted in higher antioxidant status (superoxide dismutase and catalase) compared to other groups (P < 0.05). Testosterone levels were higher in T3 than in other groups (P < 0.05). All female hormones (LH, FSH, estradiol, and progesterone) were substantially augmented by the addition of BSL. Additionally, the BSL groups exhibited higher GSI, HSI, VSI (male only), egg diameter (mm), mean number of fry/fish, and mean fry weight (g) compared to the control group (P < 0.05). Expression of reproductive-associated genes (vasa, nanos1a, nanos2, dnd1, pum1, AMH, and vtg) were significantly up-regulated in the gonads of fish in the 0.03 g/m3 treatment. The histological gonadal structure exhibited that BSL improved gonad maturation in both genders of Tilapia fish. Overall, adding a mixture of B. subtilis and B. licheniformis (0.03 g/m3 water) can accelerate reproductive performance in Red Tilapia through up-regulation of reproductive genes and enhance the health profile.

Dietary carbohydrate to lipid ratio affects growth, reproductive performance and health of female yellow catfish (Pelteobagrus fulvidragrus): a lipidomics analysis

This study aimed to examine the impact of dietary carbohydrate to lipid (CHO/L) ratio on the growth, reproductive, and offspring performance of broodstock yellow catfish, and to elucidate the metabolic differences between mothers and offspring using lipidomics. Five isonitrogenous and isoenergetic diets with varying CHO/L ratios (0.65, 1.44, 2.11, 3.13, and 5.36) were fed to three groups of 35 female broodfish in a pond-cage culture system. After an eight-week feeding trial, the dietary CHO/L ratio had a significant impact on the growth and reproductive performance of female yellow catfish. The weight gain ratio (WGR) and specific growth rate (SGR) in the CHO/L0.65 and CHO/L2.11 groups were significantly higher than those in the CHO/L5.36 group (P < 0.05). The fertilization and hatching rates were the highest when the dietary CHO/L ratio was 0.65 and 2.11, respectively. When the dietary CHO/L ratio was 3.13 and 5.36, the plasma contents of testosterone (T) was significantly lower than those of other groups (P = 0.013), and the plasma vitellogenin (VTG) content was the lowest when the CHO/L ratio was 5.36. The plasma contents of estradiol (E2) significantly decreased with increasing dietary CHO/L ratio (PL = 0.012). Lipidomic analysis revealed that the ovary primarily consisted of five subclasses in terms of lipid composition, namely triglyceride, fatty acyl, sterol, glycerophospholipid, and sphingolipid; however, sphingolipids were not detected in the larvae. The relative expression levels of the ovarian lipid metabolism-related genes sterol regulatory element binding protein 1 (srebp1), acetyl-coa carboxylase (acc), delta (12)-oleate desaturase (fad2), and elongation of very long chain fatty acids protein 5 (elvol5) significantly increased with increasing dietary CHO/L ratio (P < 0.05). The relative expression levels of lipid metabolism-related genes srebp 1, peroxisome proliferator activated receptor α (pparα), carnitine palmitoyl transferase 1 isoform (cpt), adipose triglyceride lipase (atgl), fad2, and elvol5 in offspring larvae were initially increased and then decreased with increasing dietary CHO/L ratios until reaching a maximum at a ratio of 2.11 (P < 0.05). In conclusion, based on the broken-line regression of the dietary CHO/L ratio and egg diameter, the optimal dietary CHO/L ratio was 1.91 for broodfish yellow catfish. A high-CHO/L ratio diet results in increased lipogenesis and hepatic lipid accumulation in maternal organisms, leading to impaired reproductive performance and reduced offspring quality.

Spawning performance of 3-year-old Pacific bluefin tuna Thunnus orientalis exposed to a phase-shifted photoperiod regime

The effects of a phase-shifted photoperiod regime to advance maturation and spawning were examined in 3-year-old Pacific bluefin tuna Thunnus orientalis. Fish in three broodstock groups reared in sea cages were separately transferred at age 2 years to land-based indoor tanks, in June or July, in each of the three trial years; they were then exposed to a 2- or 2.5-month advanced photoperiod cycle. In all three trials, when the fish were 3 years old, the spawning was initiated 2–3 months before the normal spawning season. During the continuous spawning, the fish were maintained under a constant long photoperiod of 15 h light and water temperature of 24–25 °C. In the 2019/2020 trial, 114 spawning days were recorded between March and July 2020 in a group of 28–30 females and 23–28 males; in the 2020/2021 trial, 100 days were recorded between April and July 2021 in a group of 30–32 females and 20–22 males; and in the 2021/2022 trial, 138 days were recorded between April and September 2022 in a group of 6–8 females and 7–10 males. The number of eggs produced daily peaked 1–2 months after the onset of spawning and thereafter decreased. Egg diameter showed a negative relationship with days elapsed from the onset of spawning. The analysis of parentage assignment of the larvae in the 2019/2020 trial showed that at least 50% of females and 75% of males contributed to the spawning, whereas histological observation of gonads in the 2020/2021 trial showed that 33% of females completed vitellogenesis and 85% of males reached spermiation. The analysis of parentage assignment also showed that the spawning interval of females declined between March and June, and the mean number of eggs produced daily per female peaked in April and decreased until June. Our observations demonstrate that manipulation of a phase-shifted photoperiod regime is a powerful technique for advancing maturation and spawning in the Pacific bluefin tuna at age 3 years.

Evaluating the potential importance of individual identity, maternal traits, and environment as predictors of egg characteristics in walleye Sander vitreus

Individual and environmental factors may influence gamete characteristics and contributions to recruitment in fishes. We tested for the influence of maternal, abiotic, and biotic factors on egg diameter and quality (i.e., oil droplet diameter) for walleye Sander vitreus in Escanaba Lake, Wisconsin, during 2018–2023 (omitting 2020). Analyses were conducted on fish captured once and for the same individuals captured multiple times during our study period. In the single-capture analysis, increasing maternal length was weakly related to larger egg diameter and oil droplet size. Increased yellow perch abundance was somewhat related to increased intra-clutch variation, whereas a later ice-off date was related to reduced intra-clutch variation. Fish that spawned later had more variable egg and oil droplet diameters. Among fish that were sampled over multiple years, individual identity was a strong predictor of egg and oil diameter. Our results suggest that regulations that preserve among individual variation in egg traits could increase the chances that environmental conditions will be favorable for spawning and recruitment for at least some fish.

Paleoparasitological studies of the woolly mammoth (&lt;i&gt;Mammutus primigenus&lt;/i&gt; (Blumenbach, 1799))

Mammoth fauna found in the permafrost in Yakutia are usually well-preserved, with up to 90% of unique discoveries, including those with soft tissues and fossil animals with intact biological fluids. Despite the exceptional preservationconditions in the deep permafrost, the remains of woolly mammoth have not been used in paleoparasitological research. This article introduces the initial findings of a paleoparasitological investigation conducted on thawed samples obtained from a woolly mammoth. The research material consisted of the gastrointestinal contents of a woolly mammoth found in the Bulunsky district on the Bykovsky Peninsula in 2022. The mammoth’s remains were discovered in permafrost and were consistently frozen until sampling, maintaining their shape well. Traditional helminthological methods, such as native smear and the Fulleborn method, were used. For the first time, eggs and larvae of helminths from the Nematoda class, including the Ascaris eggs from the Ascaridata suborder, family Ascarididae Baird, 1853 were identified in frozen-thawed samples of the woolly mammoth. A total of 13 eggs were found, showcasing excellent preservation that allowed for visualization of eggs at various developmental stages and measurement of eggshell size and thickness. The diameter of the Ascaris eggs from the woolly mammoth (Mammutus primigenus (Blumenbach, 1799)) was 73.25 ± 1.47 microns, with a shell thickness of 4.10 ± 0.20 microns. Additionally, four varieties of whole larvae and larvae fragments of the Nemathelminthes type within the Nematoda class were identified for the first time. These discoveries contribute to our knowledge of ancient fossil animals parasites and require further exploration.

Egg Quality and Fecundity of Clarias gariepinus Broodstock Cultured at Different Water Depths in Indoor Concrete Tanks

Aims: To investigate the fecundity and egg quality of C. gariepinus broodstock raised at 0.50 m, 0.75 m and 1.0 m pond water depth. Study Design: Treatments were assigned using complete randomized design. Place and Duration of Study: Fish Farm Complex of the Akwa Ibom State University (AKSU), Nigeria. Methodology: Nine female broodstock of C. gariepinus averaging 2.51 – 2.53 kg and 64.30 – 67.24 cm were raised for six months at 0.50 m, 0.75 m and 1.0 m pond water depth; referred to as treatments A, B and C, respectively Experimental fish were fed 42% crude protein commercial feed. The fecundity, relative fecundity, gonadosomatic index (GSI), egg weight and size were assessed. Results: The results revealed that the egg quality significantly (P=.00) increased with the water depth of the broodstock culture tank. Egg weight and GSI values from treatment C (363.40±0.57 g and 14.40±0.01 %, respectively) were significantly (P = .007) higher than those of treatment A (267.30±0.06 g and 10.66± 0.06 %, respectively) but showed no significant difference with those of Treatment B (331.07±1.20; 13.09±0.04 %). The corresponding egg diameter (1.01±00; 1.08±0.03 and 1.21± 0.01g), fecundity and relative fecundity of broodstock also increased with pond water depth (P = .003): 182,120.0±503.67, 72.66±0.40 &gt; 185,618.3± 745.98, 73.37±0.18 &gt; 188, 967.1± 295.19, 74.89±0.18, respectively. Conclusion: The water depth of the broodstock maintenance pond enhances fecundity and egg quality; it is better at 1.0 m depth for successful fry production. Broodstock may be maintained at lower pond water depths for growth purposes; prior to breeding.

IMPROVE SPAWNING QUALITY OF KISSING GOURAMI (HELOSTOMA TEMMINCKII) WITH COMMERCIAL FEED CONTAINING GLUTATHIONE AND VITAMIN E

This research is needed to accelerate spawning by adding glutathione and vitamin E in the feed to produce quality fish seeds. The aim is to determine the effect of adding vitamin E to commercial feed containing glutathione on increasing gouramy spawning. All treatment was carried out for two months using a Completely Randomised Design (CRD) with 4 treatments and 3 replications. Treatment A (glutathione), B (glutathione and vitamin E 150 mg.kg–1), C (glutathione and vitamin E 300 mg.kg–1), and D (glutathione and vitamin E 450 mg.kg–1). 12 broodstock with male:female ratio of 1:1, weight range of 90-130 g obtained from nature. They fed as much as 5% of the fish body weight thrice daily. The results showed that the highest hatching rate was 99.67% in treatment D. The egg diameter in treatment C showed the best results (0.88 mm). The highest fecundity was 21.257 g in treatment D. The highest survival was 95.56% in treatment D. All feed treatments with a combination of glutathione and vitamin E gave a better response than the addition of glutathione alone. Polynomial regression analysis of the egg diameter parameter showed that the optimal dose of vitamin E was 282 mg.kg–1.

Temperature-size responses during ontogeny are independent of progenitors' thermal environments.

Warming generally induces faster developmental and growth rates, resulting in smaller asymptotic sizes of adults in warmer environments (a pattern known as the temperature-size rule). However, whether temperature-size responses are affected across generations, especially when thermal environments differ from one generation to the next, is unclear. Here, we tested temperature-size responses at different ontogenetic stages and in two consecutive generations using two soil-living Collembola species from the family Isotomidae: Folsomia candida (asexual) and Proisotoma minuta (sexually reproducing). We used individuals (progenitors; F0) from cultures maintained during several generations at 15 °C or 20 °C, and exposed their offspring in cohorts (F1) to various thermal environments (15 °C, 20 °C, 25 °C and 30 °C) during their ontogenetic development (from egg laying to first reproduction; i.e., maturity). We measured development and size traits in the cohorts (egg diameter and body length at maturity), as well as the egg diameters of their progeny (F2). We predicted that temperature-size responses would be predominantly determined by within-generation plasticity, given the quick responsiveness of growth and developmental rates to changing thermal environments. However, we also expected that mismatches in thermal environments across generations would constrain temperature-size responses in offspring, possibly due to transgenerational plasticity. We found that temperature-size responses were generally weak in the two Collembola species, both for within- and transgenerational plasticity. However, egg and juvenile development were especially responsive at higher temperatures and were slightly affected by transgenerational plasticity. Interestingly, plastic responses among traits varied non-consistently in both Collembola species, with some traits showing plastic responses in one species but not in the other and vice versa. Therefore, our results do not support the view that the mode of reproduction can be used to explain the degree of phenotypic plasticity at the species level, at least between the two Collembola species used in our study. Our findings provide evidence for a general reset of temperature-size responses at the start of each generation and highlight the importance of measuring multiple traits across ontogenetic stages to fully understand species' thermal responses.

The reproduction performance of catching Planiliza subviridis (Teleostei: Mugilidae) in different moon periods from Jepara Coast, Central Java, Indonesia

Abstract. Yudiati E, Yuniarti T, Trianto A, Arifin Z, Ruliaty L, Soleh M, Naryaningsih A, Suryati. 2024. The reproduction performance of catching Planiliza subviridis (Teleostei: Mugilidae) in different moon periods from Jepara Coast, Central Java, Indonesia. Biodiversitas 25: 1823-1830. Mullets (Planiliza subviridis Valenciennes 1836) are highly promising species for aquaculture development. Information on the reproductive performance of wild-caught fish is crucial for enhancing mullet production. This study aimed to assess the gonadal maturity level of female mullets captured during full and new moon phases. Sampling using lift nets was conducted from June to July 2023, comprising 104 individuals, 51 during the new moon and 53 during a full moon. Fish caught during different moon phases were measured for gonad maturation level (GML) and morphometric parameters (body weight, total length, head length, body width, and head width), assessed for gonad somatic index (GSI), fecundity, and egg diameter. Over 50% of individuals were at GML III during dark moon phases, while during bright moon phases, only 10-15% were at GML III; GSI ranged from 0.6-15%. The fecundity of GML I and II females was higher during the full moon (220,212-395,000 eggs per individual) compared to the new moon, while GML III females during dark moon phases ranged from 225,000-250,000 eggs. Mullets exhibit increased reproductive output during the new moon phase and engage in synchronous spawning during moonlight cycles. Therefore, prospects for mullet culture appear promising, with cultivation and domestication suggested during new moon periods.

Reproduction biology of mullet fish (Mugil dussumieri) found in Bandar Khalipah Waters Serdang Berdagai Regency, North Sumatera Province

The Mullet fish (Mugil dussumieri) is one of the types of marine fish that is caught in waters Bandar Khalifah. This limited information reproductive aspects of Mugil dussumieri, such as sex ratio, gonad maturity level, gonad maturity index, fecundity, egg diameter, and gonad histology, that can be used as a guideline for the management of mullet resources to ensure sustainable utilization. This study was conducted from January to March 2023, and method used in this research was random purposive sampling. Fish samples were taken in 3 station is estuary, Pandang River and the coastal waters of Bandar Khalifah District, Serdang Berdagai Regency, North Sumatera Province, which was divided into 3 stations using a census sampling method. The total catch was sampled once a month for 3 months. The fishing gear used was a Gillnet with a mesh size of 1.5 cm. The data analysis included measurements of the samples, gonad maturity level, fecundity, and gonad histology. The reproductive results showed an unbalanced sex ratio of 1:3. The gonad maturity level of the mullet fish ranged from gonad maturity level I to gonad maturity level IV. The egg fecundity ranged from 963 to 129,311 eggs, and based on the egg diameter, the Mullet fish is classified as a partial spawner. These studies are crucial for obtaining information that can be used as a guideline for the management of Mugil dussumieri resources to ensure sustainable utilization.

The comparative egg physical characteristics from four poultry species

In this study, we examined the physical characteristics of two local breeds (Cemani chicken and Mojosari putih duck) and two imported breeds (White Leghorn chicken and Peking duck). A total of 280 eggs were tested. Egg physical characteristics and hatchability were analyzed using ANOVA with consideration for breed effects using GLM (SPSS version 25). Peking ducks have a heavier, larger mean of geometric diameter, larger volumes, and larger surface area of eggs (p<0.05). Among them, the Cemani chicken is the smallest in the world (p<0.05). Cemani chicken and Mojosari putih ducks had the highest sphericity and shape index scores, and were significantly different from White Leghorn chickens and Peking ducks (p<0.05). Density parameters were highest in Cemani chickens as well as in White Leghorn chickens, but were significantly different from Peking ducks and Mojosari putih ducks (p<0.05). Hatchability was related to the shape index value. Mojosari putih ducks and Cemani chickens have a higher shape index than White Leghorn chickens and Peking ducks. In summary, the Peking duck was better, but the hatchability was higher for the Mojosari putih duck and Cemani chicken.

Different dosages effectiveness of Ovaprim on the maturation of freshwater lobster (Cherax quadricarinatus)

Freshwater lobsters have been developed as a commodity for consumption since 2003. The need for this commodity is increasing but production is still very low, so the price of freshwater lobsters is quite high and expensive. Therefore, it is necessary to carry out reproduction to carry out the seeding process for Freshwater Lobsters (LAT) using an injection technique in the form of the Ovaprim Hormone to accelerate the maturity of the LAT gonads. This study aims to examine the administration of different doses of the ovaprim hormone on the maturation of freshwater lobster broodstock. The research was conducted for 60 days. The method used was a Randomized Block Design (RAK) with 4 treatments and 3 replications. The treatments in this study were P0 (control), P1 (0,3 ml), P2 (0,5 ml) and P3 (0,7 ml). The parameters observed in this study were Gonad Maturity Index (IKG), Egg Diameter and Pleopode Fecundity. The results of the observations showed that giving different doses of ovaprim to the maturation of freshwater crayfish was not significantly different (P&lt;0.05) to the Gonad Maturity Index IKG), Egg Diameter and Pleopode Fecundity but was significantly different to the P0 (control) treatment. The best treatment in this study was treatment P3 (0.5 ,l) because it had the highest performance between the other treatments.Keywords: egg diameter; fecundity; freshwater lobster; maturation; ovaprim

Effectiveness of different photoperiods on gonad maturity and reproductive performance of freshwater crayfish (Cherax quadricarinatus)

This study aimed to determine the effectiveness of different photoperiod on gonad maturity and reproductive performance of freshwater crayfish. The study was conducted on July 22th - August 22th in the Green House Samudra University. Test fish used is seed of cherax quadricarinatus measuring 4-5 inches. The methods used in this study was Completely Randomized Design (CRD)with 4 treatments and 3 replications. The treatments in this study were P1 (8 hours light, 16 hours dark), P2 (10 hours light, 14 hours dark), P3 (12 jam hours light, 12 hours dark), and P4 (14 hours light, 10 hours dark). Seeds of fish was put in a containing 8 liters of water volume with a stocking density of of 1 tails male and female each container. The frequency of feeding is done 3 times a day at 08.00 am, 16.00 pm and 20.00 pm. The results showed that different natural feeding teratments had a very significant effect on the absolute weight, gonad maturity level (TKG), gonad maturity indexs (IKG), fecundity, and egg diameter. The best treatment in this study was P1 treatment (8 hours light, 16 hours dark) because it had a high-performance value compared to other treatments.Keywords: Absolute weight; Cherax quadricarinatus; Fecundity; Gonad; Photoperiod.