The embryonic and larval development of black skirt tetra, Gymnocorymbus ternetzi, are described under controlled laboratory conditions. In addition, major histomorphological changes and the allometric growth patterns during larval development have been described. The laboratory-reared broodstock, that is 1 year of age, were spawned. Hatching occurred 20-21 h after spawning at 24 ± 0.5°C. The cleavage was finished in 2 h and the early blastula stage occurred at 2:04 hours after spawning. The gastrulation started at 3:20 hours and 30% epiboly was observed at 3:34 hours after spawning. Eight-somite stage was observed at 08:33 hours. And embryonic developmental stage was completed at 21 h after spawning. The newly hatched larvae were 1442 ± 14.3 lm in mean total length (TL). The mouth opened at 3 days after hatching (DAH). The yolk sac had been totally absorbed and the larvae started to swim actively within 3-4 days. Notochord flexion began at 11 DAH. The metamorphosis was completed and the larvae transformed into juveniles at 32 DAH. In this paper, the full developmental sequence from egg to juvenile of G. ternetzi is described for the first time.

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In this study, the embryonic and larval development stages of one of the most important ornamental fish serpae tetra (Hyphessobrycon eques) are described. The early life stage is documented from fertilization until the beginning of the juvenile period. The fertilized eggs (the average diameter = 938.55 ± 35.20 µm) were incubated at a water temperature of 26 ± 0.5°C. The cleavage finished in 1:10 hr (=h) and the early blastula stage occurred at 1:26 hr post fertilization (hpf). The gastrulation started at 3:05 hpf, and 50% epiboly was observed at 3:25 hpf. Segmentation stage was monitored at 7:26 hpf. Embryonic developmental stage was completed and hatching occurred 20–21 hpf. The total length (TL) of newly hatched larvae was 2.64 ± 0.21 mm. The larval development of serpae tetra was divided into four different periods: Yolk‐sac larva (1–4 DAH, TL = 2.77 ± 0.09 mm ‐ 3.85 ± 0.11 mm), preflexion larva (5–12 DAH), flexion larva (13–15 DAH, TL = 5.78 ± 0.46 mm on the 15th day) and post‐flexion larva (16–30 DAH, TL = 10.7 ± 0.27 mm on the 28th–30th days). The mouth and anus are closed at 1 DAH. The mouth and anus opened at 4 DAH. Exogenous feeding started on the 4th day. The first gulping of the swim bladder was on days 3. The larva begins to swim freely, and the yolk sac was completely consumed at 4 DAH. Histological structures of the eye and brain of new hatched larva were clearly identified at 1 day after hatching (DAH). According to histological findings, the digestive system (stomach, intestine) started to develop and the liver could be seen on the ventral side of the swim bladder at 5 DAH. No histological difference was observed between the anterior intestine and the posterior intestine at 15–16 DAH. The larval metamorphosis was completed, and the larvae transformed into juveniles at 28–30 DAH.

Commercial bath sponge population in the Mediterranean has been recently reduced due to diseases and the depletion of natural banks. The commercial supply is far below the demand on the last10^15 years. In this study, we aimed to investigate the farming performance of Spongia o⁄cinalis in the Dardanelles. Sponges collected from the Dardanelles cut into pieces of di¡erent weight. They were divided into two groups depending on the wet weight ranging from 50 to150 g (mean weight 102.6 AE 4.81g) and from 160 to 360 g (mean weight 235.8 AE 8.56 g). Three rope systems located parallel to each other with 6^7 m inter-distance were constructed for the cultivation of sponges. At the end of the study, while small-sized sponges could reach mean wet weight of 120.7 AE 14.8 g, large-sized sponges reached mean wet weight of 247.6 AE 22.4 g. Growth rates were estimated 5^17% at 21st month. The survival rates were found 82% and 88%.

In this study, the larval development of freshwater angelfish, Pterophyllum scalare, was described under controlled aquarium conditions. Major histomorphological changes and the allometric growth patterns during the larval development have been described. The larvae were obtained from three pairs of freshwater angelfish, which were maintained in glass tanks. The larvae were sampled for measurement and photography. They were observed under a stereomicroscope, photographed using a photomicrographic system. The larval development of angelfish were described from 1 days after hatching (DAH) to 24 DAH. Embryonic developmental stage was completed at day 3 after spawning at 24±1ºC. The newly hatched larvae had 4.24±0.28 mm total length (TL). The mouth opened at 3 DAH. The larvae started to swim actively within the next 3-4 days.Notochord flexion began at 3-4 DAH. The yolk sac has been totally absorbed at 6 DAH. The metamorphosis was completed and the larvae transformed into juveniles at 23-24 DAH.Keywords: Ornamental fish, aquarium, larval development, allometric growth.Tatlı Su Melek Balığının (Pterophyllum scalare) (Teleostei: Cichlidae) Larval Gelişimi ÖzetBu çalışmada, tatlı su melek balığının (Pterophyllum scalare) kontrollü akvaryum koşullarında larval gelişimi incelenmiştir. Larvalar, cam tankta tutulan üç çift tatlısu melek balığından elde edilmiştir. Elde edilen larvalar ölçüm ve fotoğraflama için örneklenmiştir. Alınan örnekler stereomikroskop altında incelenmiş ve mikro fotoğraflama sistemi ile fotoğraflanmıştır. Melek balıklarının larval gelişimleri, yumurtadan çıktıktan sonraki 1 ile 24 gün arasında tanımlanmıştır. Larval gelişim boyunca gözlenen temel histomorfolojik değişimler ve allometrik büyüme modelleri tanımlanmıştır. Denemede, embriyonik gelişim safhası, 24±1ºC'de yumurtlamadan sonraki 3. günde sona ermiştir. Kuluçkadan yeni çıkmış larvaların 4,24±0,28 mm total boy (TL) uzunluğa sahip oldukları belirlenmiştir. Ağız açılımı, kuluçkadan çıktıktan sonraki 3.günde gerçekleşmiştir. Larva takip eden 3-4 gün içerisinde aktif olarak yüzmeye başlamıştır. Notokorda fleksiyonu açılımdan sonraki 3-4.günlerde başlamıştır. Besin kesesi, açılımı takip eden 6. günde tamamen tükenmiştir. Açılımdan sonraki 23-24. günlerde metamorfoz tamamlanmış ve larva juvenil formuna dönüşmüştür.Anahtar Kelimeler: Süs balıkları, akvaryum, larval gelişim, allometrik büyüme.