Gonad maturity level and somatic index of sea cucumber Acaudina sp. (caudinidae, molpadida, holothuroidea) In Delta Wulan Waters, Demak Regency, Indonesia

Sea cucumber Acaudina sp. belongs to the family Caudinidae, Order Molpadida, Class Holothuroidea. These animals have an important role in the benthic ecosystem. The purpose of this research was to determine the gonad maturity level and Gonad Somatic Index of Acaudina sp. in Delta Wulan Waters, Demak Regency. In total, 64 individuals of Acaudina sp. were taken in April 2021 and 148 individuals were taken in May 2021. In April observation, the highest gonad maturity level for females was at level 3, while the highest gonad maturity for male was at levels 1 and 2. Furthermore, in Mei observations, the highest gonad maturity level for females was at level 2 and for males, the highest gonad maturity level was at level 3. According to April observation, values GSI (Gonad Somatic Index) has a range 0.22 - 6.09 % and for May observation, value GSI has a range 0.04 – 2.24%. Hence, there is a positive correlation between gonad weight and GSI values in sea cucumber Acaudina sp.

Reproductive Characteristics of the Pond-Farmed Sultan Fish (Leptobarbus hoevenii)

Highlight ResearchThe reproductive characteristics of L. hoevenii were examinedThe potentially smallest maturity sizes of female and male L. hoevenii were 350 g and 180 g, respectivelyThe fecundity of a 1,000 g L. hoevenii can be more than 100,000 eggsL. hoevenii was determined as a multiple spawnerAbstractSultan fish (Leptobarbus hoevenii) is a high value freshwater fish, cultured in some Southeast Asian countries, including Malaysia and Thailand. However, information on its reproductive characteristics is very scarce. This study examined the gonadosomatic index (GSI), fecundity, egg diameter, and determined whether L. hoevenii is a single- or multiple-spawner. Twenty male and female pond-farmed L. hoevenii broodstock were obtained to measure their total length (TL), body weight (BW) and gonad weight to calculate the GSI. Ten females were randomly sampled from the 20 to determine their fecundity. A total of 1,500 eggs were sampled from each female. The egg diameter was measured then its frequency distribution was analyzed to detect the number of egg class group, and to determine whether L. hoevenii is a single- or multiple spawner. The female L. hoevenii examined were 32.2-47.1 cm and 350-1,200 g, while the males were 30.7-45.8 cm and 180-970 g in TL and BW, respectively. All female specimens contained gonads. The potentially smallest mature samples were recorded at 350 g (female) and 180 g (male). GSI for the female and male L. hoevenii were 1.81-12.28 % and 1.03-5.09 %, respectively. The fecundity was 35,467 -128,067 eggs, while the highest fecundity was observed in a 1,000 g fish. The observed egg diameter ranged from 500 to 1,855 μm. Two to five groups of egg class were detected, indicating that L. hoevenii is a multiple spawner.

Allopatric origin of sympatric whitefish morphs with insights on the genetic basis of their reproductive isolation

The European whitefish (Coregonus lavaretus) species complex is a classic example of recent adaptive radiation. Here we examine a whitefish population introduced to northern Finnish Lake Tsahkal in late 1960s, where three divergent morphs (viz. littoral, pelagic and profundal feeders) were found ten generations after. Using demographic modelling based on genomic data we show that whitefish morphs evolved during a phase of strict isolation, refuting a rapid symmetric speciation scenario. The lake is now an artificial hybrid zone between morphs originated in allopatry. Despite their current syntopy, clear genetic differentiation remains between two of the three morphs. Using admixture mapping three quantitative trait loci associated with gonad weight variation, a proxy for sexual maturity and spawning time, were identified. We suggest that ecological adaptations in spawning time evolved in allopatry are currently maintaining partial reproductive isolation in the absence of other barriers to gene flow.

Synchronicity of Condition Factor with Reproductive Development in Rainbow Snakehead (Channa bleheri Vierke, 1991)

Background: Condition factor is an important factor to determine the general well being of any species. It is influenced by different factors like feeding, age of the fish, season, development of gonads etc. Reproductive development on other hand is a crucial factor in determining the condition of fish as gonad weight has certain impact on increasing the weight of fish as well as the condition of the fish. The experiment was thus to determine whether there is any synchronicity of reproductive development in the near threatened snakehead Channa bleheri with respect to its condition factor value.Methods: The condition of C. bleheri was closely monitored based on lenth-weight data round the year. The gonadal development of the species was determined calculating the Gonado-Somatic Ratio (GSR) as well as histological observation of the gonads.Result: It was found that the value of condition factor was directly proportional to the gonadal development which signifies the importance of gonad development in determining the fish condition. As there are many established factors that determine a fish condition, the inputs drawn out from the reproductive development can help to determine the condition of the fish.

Some Biological Aspects of Cultured Ompok Pabda (Hamilton, 1822) Collected from A Local Fish Farm in Mymensingh, Bangladesh

An experiment was conducted to observe some biological aspects including growth, sex ratio, gonadal maturity, artificial insemination, fecundity, fertilization, hatching and larval development of O. pabda in a private hatchery. Total weight of the sampled fish varied from 1.60±0.43 to 111.12±6.83 g and length varied from 3.57±0.65 to 21.22±1.84 cm with the SGR 2.85±0.18 and ADG 0.73±0.05. The length and weight of the fish had a strong correlation (r²=0.966). Female dominance over male has been observed in the species. The male to female ratio was 1:1.48. Females were 16.8 cm in length at first maturity, while males were 16.6 cm in length. The GSI of female were ranged from 2.93 to 4.77 with the mean of 3.77±0.60 during the study period. The fecundity of O. pabda was ranged from 5675 to 19626 with the mean of 12503±4192 for the corresponding length 21.23±1.71, body weight 111.12±7.6 and gonad weight 4.19±0.87. Fertilization rate, hatching rate and larval development observed during the experiment. Scattered diagram for length-weight, fecundity-length, fecunditybody weight and fecundity-gonad weight relationship shows a perfect correlation both arithmetically and logarithmically.

Growth and reproduction performance of sea cucumber (Stichopus sp.) fed with different feed regime

Growth and reproduction performance of sea cucumber (Stichopus sp.) fed with different feeding regimes. This study aims to know the effects of different feeding regimes on sea cucumbers' growth and gonad development. Sea cucumbers used in this experiment were collected from the natural habitat in Northern Bali waters. Five individuals of sea cucumber (BW 334 ± 58 g; TL 22,5± 3,5 cm) were placed in each of four concrete tanks size 0,85 x 2 x 0,5 m3 with flow-through water systems. There were two feeding treatments in this study: A) fresh benthos and B) a combination of fresh benthos and seaweed (Ulva and Sargassum). Feed was given as much as 2.5 to 5 %, once in the afternoon. Observed variables were the growth and gonad stage and the weight at the end of the experiment. The study showed that the different feeding regimes significantly influenced the sea cucumber growth and gonad weight, but not the gonad stage. Sea cucumber fed with a combination of benthos and seaweed performed better growth and higher gonad weight. The difference in the feed did not affect gonad development.

Fecundity and condition of Chrysichthysnigrodigitatus (Family Claroteidae) in Yewa Lagoon, Nigeria

The minimum and maximum standard length of females caught was 8.0cm (14.5g body weight) and 14.6cm (53.4g body weight) respectively while the males were 10.1cm (19.8g) and 17.1cm (68.6g). The gonadosomatic index (GSI) for females ranged between 6.55 and 25.57 while males ranged between 5.68 and 16.55. Significant (P<0.05) relationships were observed between standard length, body weight, gonad weight and fecundity. There was significant (P<0.05) relationship between body weight and fecundity. Body weight and GSI had no significant (P>0.05) relationship with condition factor in C. nigrodigitatus in Yewa Lagoon. The condition factor (K) ranged between 1.58 and 2.92 for the females while males ranged between 1.08 and 2.79. The condition of female fish was slightly better than that of male fish of the same length.

Determination of breeding performances of some commercial fishes of the Bay of Bengal.

Bangladesh is blessed with a coastline of 710 km along the north and north-east part of the Bay of Bengal, having a water area of about 48,365 nmi2 (165,887 km2), as large as the country itself. In these marine and coastal waters there are about 475 species of fish, many of which play an important role in the national economy in both employment in fisheries and income generation. Identification of the breeding pattern of commercial fish is important for hatchery installation as well as coastal aquaculture. Summarized data of breeding performances such as breeding season, body length and weight, gonad weight and fecundity of 15 marine fish of the coastal and offshore waters of Bangladesh are given. The breeding pattern of the fish shows a prolonged spawning season, almost throughout the year. Variations in body length and weight, and in gonad weight and fecundity in the marine environment are also given. As these fish are marine, spawning occurs in a salinity of about 30‰ and following larval development in offshore waters, juveniles migrate towards shallow coastal waters, for shelter and feeding, where they pass their young life.

Reproductive aspects of Chiton virgulatus in Bahía de La Paz, Gulf of California, Mexico

This study analyzed the reproductive cycle of Chiton virgulatus and its relationship with air temperature (AT) sea and surface temperature (SST), photoperiod, and tidal cycle (TC) in Bahía de La Paz, in the coast of the Gulf of California. Monthly samples were collected from September 2008 to September 2009. The parameters recorded included total length, total weight, and gonad weight of each organism; the gonad was processed using a histological technique, and the gonadal index and length at first maturity (L50) were estimated. C. virgulatus displays partial spawning with a reproductive peak in summer and autumn (July to December). The frequency of ripe organisms was associated with rises in SST (30.6 ºC), AT (29.9 ºC), and TC (68 cm, high tidal), while photoperiod (longer days) regulated the frequency of developing organisms. The length at first maturity was 29.7 mm. Chiton virgulatus is a polyplacophoran species in which high temperatures and high tides influence reproductive timing, while an increase in daylight boosts gonad development.

Relationship between External Morphology and Gonads in Rainbow Lizard (Agama agama) in Obafemi Awolowo University, Ile-Ife, Nigeria

Background of the Study: The morphology of any reptile may be affected by different environmental factors such as climate change and habitat related features such as availability of food and other resources. Objective: This study aimed at determining the morphology and sexual variation of Rainbow male and female lizards (Agama.agama) in Obafemi Awolowo University. Study Design: Three locations in the University were selected (Student Hostels, Academic Area and Staff Quarters) and rainbow lizards were sampled from June to December 2019. Results: A total of 93 lizards were sampled, body parameters were measured, and the gonads were weighed after dissection. There was a positive correlation (0.98 & 0.78) between the body weight and gonad weight of the male and female lizards in all the three locations. Also, the specimen from the academic area of the University had the least body and gonad weight, while the samples caught in the staff quarters had the highest body and gonad weight. The Principal Component Analysis (PCA) showed a relationship in the body and gonad weight with few differences from samples captured in the academic area. Conclusion: In summary, external morphology of the rainbow lizards from all the three locations were similar with little difference in body weight. There was a positive relationship between external morphology and gonads of rainbow lizards.