Betta fish Betta splendens have morphological differences between males and females. Male betta fish have more attractive body colors and shapes than females. This causes the selling value and market demand for males to be higher than that of females. Therefore, it is necessary to make efforts to get enough male fish through masculinization. So far masculinization or the sex reversal into males using androgen hormones before sex differentiation occurs. However, the use of steroid hormones has been banned and reduced, because they cause environmental and public health problems and are carcinogenic. This study used natural honey solution to determine the effect of length immersion time in the honey solution and to obtain a suitable larval age for masculinization on the early gonadal formation and larval survival after treatment. Masculinization was carried out using larvae in three treatments immersion time as follows 10 hours, 11 hours, 12 hours, and control. After that, the treatment was continued with the best results of the treatment using 7-day old larvae (D7), D9, and D11. Each treatment using 30 larvae was immersed in a honey solution of 3 liters with a concentration of 5 ml / L. The treatments were kept until 60 days before sex observation. Early observations of gonad formation were carried out after the larvae were D20 with HE-stained histology. The data obtained were analyzed using descriptive statistics and a chi-square test. The results showed that the treatment for 12 hours of immersion had the highest male sex ratio (93%). While the treatment on D7 larvae age in honey solution had the highest percentage in males (96%). It can be concluded that the increase in the percentage of male betta fish is influenced by the length of time immersion in the honey solution and the age of the larvae in the first week after hatching. All treatments did not affect the survival of betta fish larvae.

<p>Mud crab is one of the 12 aquaculture commodities of Ministry of Maritime Affairs and Fisheries. Control of reproduction to increase seed production through feed improvement, is one of the challenges and strategies in the mud crab aquaculture. Due to lack of knowledge about broodstock nutrition lead to producing rate of seeds still relatively low. This study aimed to obtain information on the kind of feed that has specific nutrient and plays a role in increasing the success of spawning and zoea survival. Mud crab of Scylla serrata with initial weight of 500.7±103.4 g, preferably under developed gonads were maintained in a fiber tank measuring length of 2.48 m, width 1.26 m, and a height of 60 cm which is partition sealed into 30×40×60 cm3 to put one crab. Tank was equipped with sand as a substrate as high as 15 cm and seawater system with flow rate of 1 L per six minutes and 25 cm high water. Treatments were consisted of: 1. PI (fresh meat fish of Decapterus sp. with dose of 5%), 2. PSC (fresh meat mixture of Decapterus sp. 1.8%, 3% of squid, and shrimp 1.2%), 3. PB (artificial feed dose of 10%) of BW, each treatment was repeated three times. Parameters measured were the duration of ovarian to mature, egg diameter, hatching rate, fecundity, and zoea production. Data were analyzed using ANOVA. The quality of larval measured by survival and larval fat and protein content. The results showed that crabs treated by PI and PSC showed faster to get mature compared to PB treatment (p&lt;0.05). Hatching rate of larvae in PSC treatment was higher compared to PI and PB treatments (p&lt;0.05). Furthermore, all treatments did not affect egg diameter, fecundity, and the number of zoea (p&gt;0.05). In conclusion, crab which fed fresh meat (PI and PSC) could get mature earlier, and have high percentage of the larval hatching than those of fed by PB. In fact that larvae from broodstock feed of PI has survival as well as protein and fat content were higher than those of fed by PB.</p><p>Keywords: spawning perform, broodstock feed, mud crab (Scylla serrata)</p>

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The availability of female adult mature will continuously support mud crab hatchery to produce the best quality of larvae. Bray et al., (1990b) proposed that zoea length can be used as an index of larval quality. Larval quality is dependent on the physiology condition related to the growth and survival rate of several larval development stages (Racotta et al., 2003). The mortality in all development stages was due to the high sensitivity of larvae for the environment changes. Two aquariums and sterilized water were used in all rearing process and larvae of Scylla serrata fed once a day. It was fed by rotifer (Branchionus plicatilis) and Artemia sp on the third and fifth days. The results showed that the eye was a distinguishing characteristic between zoea I and zoea II. Development of zoea I range about 0 (zero) to fourth days and zoea II about fifth to seventh days. Observation of growth for six days indicate an increasing significantly on the fourth to sixth days. The survival rate of Scylla serrata larvae without food holds three days out. Otherwise, larvae that were fed on everyday hold seven days out. ABSTRAKKetersediaan induk yang matang telur secara berkesinambungan akan sangat mendukung usaha pembenihan kepiting bakau dalam menghasilkan larva dengan kualitas yang baik. Bray et al., (1990b) bahwa panjang zoea dapat digunakan sebagai suatu indeks kualitas larva. Selain itu, kualitas larva juga bergantung kepada kondisi fisiologis larva dan berkaitan dengan rata-rata pertumbuhan dan sintasan selama beberapa tahapan larva (Racotta et al., 2003). Seluruh proses pemeliharaan digunakan air steril dengan menggunakan wadah berupa akuarium sebanyak dua buah. Larva kepiting bakau, S. serrata selama pemeliharaan diberi pakan satu kali sehari. Pakan yang diberikan berupa rotifer (Branchionus plicatilis) dan artemia pada hari kelima dan ketiga. Hasil penelitian menunjukkan bahwa ciri morfologi pembeda antara tahap zoea I dan zoea II adalah mata. Perkembangan zoea I berkisar antara hari 0 sampai dengan hari 4 selanjutnya zoea II antara hari kelima sampai hari ketujuh. Pertumbuhan yang diamati selama masa pemeliharaan hari pertama sampai hari keenam, menunjukkan adanya peningkatan yang signifikan pada hari keempat sampai hari keenam. Tingkat kelangsungan hidup larva S. serrata yang tidak diberi pakan dapat bertahan mencapai tiga hari. Sebaliknya untuk larva yang diberi pakan selama masa pemeliharaan mampu bertahan hingga mencapai tujuh hari.Kata kunci: Larva zoea, Scylla serrata, pertumbuhan, tingkat kelangsungan hidup

Sea cucumber population in nature is reported to have experienced exploitation pressure in various places. Natural sea cucumber reproduction (sexual) takes a long time to produce a new adult individual. This is feared to be the cause of the extinction of sea cucumbers. Sandfish, Holothuria scabra, do not include sea cucumber species which are categorized as capable of asexual reproduction. However, several laboratory-scale studies state that sandfish can be induced for asexual reproduction. This study aims to determine the level of life graduation and the growth of sandfish produced by asexual reproduction. Individual sandfish is tied with rubber bands about 60% from the anterior to the posterior. The result showed that the sandfish were successfully induced to undergo asexual reproduction which is known as “fission”. The time needed for a sandfish to break itself into 2 new individuals takes less than 2 days. The first days after dividing the body seem to be a critical period. Only 13.64% of new individuals survive the critical phase. It concluded that the growth of asexual reproduction sandfish is slow because it takes time to regenerate the scattered internal organs during the process of division.