Population of green turtle (Chelonia mydas) that laid their eggs in the Derawan Islands conservation area was declined due to various factors. The aim of this study was to determine the number of egg that was laid down into the nest for each green turtle parent and its correlation to shade, sandy beach width, and moon phase. The study was conducted from 24 January to 31 March 2015 in the Sangalaki Island. The observation of the broods stock was done by walking down the beach in the night to find out the broodstock that laid the eggs and counted the number. A sign was given to the nest of broodstock that finished laying the eggs. On the following day, nest excavation, egg collection, and the environmental measurement were conducted. Environmental conditions were measured include the depth of the nest, substrate temperature, the distance of the nest site to the shading trees and the border line of lowest tide. Data analysis was done descriptively by counting the number of eggs and environmental parameters. The results show that the average number of egg per nest was 97 items with the range of 45 - 127 items, the length of the carapace was 96 cm with a range of 86 - 107 cm, the average depth of the nest hole was 73 cm with a range of 56 - 87 cm. Broods stock of green turtle that laid more eggs would dig nest hole deeper, but there was no correlation between the carapace length and the number of the laid eggs. The average number of green turtle broods stock that lay eggs in the Sangalaki Island was 486 individual/ month with the range of 168 - 1085 individu/month. The west and east seasons affect the frequency of nesting and the laid eggs. The frequency of spawning occured throughout the year and the highest spawning frequency occured in August which coincides with the peak of the East Season. The frequency of spawning during the East Season was four times higher than during the West season. The frequency of green turtle landing was not affected by the lunar phase. Based on the location of laying egg, the beaches that were selected for laying egg are located in the northwest, northeast, and south parts of the Sangalaki Island. The Green turtle nests were commonly found in the vegetation shading areas (64%) than open sand areas (36%).

The aim of this study was to determine the diversity of fish species, and the role of the Bogowonto River estuary as the nursery and feeding ground of fishes. Seven sampling stations were determined in the estuary of Bogowonto River. Fish samples were identified, and measured the length and weight. The results showed that 2235 fishes were caught consisting of 38 species. The monthly Shannon-Wiener diversity index (H’) ranged from 1.05 to 2.38, while the evenness index (E) ranged from 0.44 to 0.74, and the species richness index (D) ranged from 0.22 to 0.45. The diversity index at each station showed the range of 1.72 to 2.29, and the evenness index ranged from 0.59 to 0.85, while the evenness index ranged from 0.22 to 0.34. The presence of the most numerous species namely Mystus gulio had the occurrence of 35.35%, and the second largest number was Moolgarda engeli 14.08% then Ambassis macrachantus 11.54%. Most fishes were juvenile with average size of <10 cm and weight <15 g. Bogowonto River estuary has played an important role in providing a nursery, feeding and spawning ground for marine, brackish and freshwater fishes.

Buntung Stream is one of the tributaries of Bedog Stream. The Bedog Stream and its tributaries in Bayem, subdistrict of Kasihan to their upstream are categorized as river of B group. The activity of pig raising which have been carried out by some people in BanyuradenGampingSleman which throw away the wastes in this area likely to have effect on physical, chemical, and biological water qualities, especially coliform bacteria.The objectives of this research were to know the changes on the water quality of Buntung Stream due to pig raising waste disposal in BanyuradenGampingSleman and to give alternative solution to the problem. Observation were conducted on the physico-chemical and also biological water qualities of the stream at four stations: Station I (±800 m upstream of the waste disposal point), Station II (at the waste disposal point), Station III (±500 m downstream of the waste disposal point), and Station IV (±900 m downstream of the waste disposal point, before the encountering of Buntung and Bedog Stream). The samples were collected at the station between 09.00-12.00 a.m repeated 10 times during June-July 2001.Based on the data analyses, it could be drawn some conclusions as follows: the pig raising wastes disposal into Buntung Stream increased water discharge and quantities of coliform group and coliform feces. The waste disposal increased total dissolved solids, ammonia, and phosphate contents but decreased dissolved oxygen and pH of the water, and did not affect the water velocity, temperature, and nitrate content. In addition, BOD5 dissolved     oxygen, and the density of coliform bacteria in Buntung Stream after receiving the pig raising wastes disposal were beyond the B group of the water quality standard in the Special Province of Yogyakarta, whereas the content of total dissolved solids, pH, ammonia, and nitrate were still within the range of the water quality standard.

The objective of this study was to determine the diversity and abundance of krustaseans in the mangrove area of Jangkaran Village, Temon District, Kulon Progo Regency. Sampling was done bi-weekly from October 2016 to February 2017 on six stations defined by ecological character. Krustasean sampling was done using cest net, trap net and hand picking along the river with the extent of each collection station about 10 m2. The captured krustasean samples were cleaned, stored in ice-cooled boxes and transported to the laboratories to be identified and grouped according to species, then measured by carapace length and individual weight. Observation of aquatic environment was done by measuring temperature, brightness, water depth, current velocity, pH, salinity, dissolved oxygen, and substrate type. The results of the observation obtained 1 order, 7 families, and 26 species. The family krustaseans found were Coenobitidae, Diogenidae, Grapsidae, Ocypodidae, Palaemonoidae, Penaeidae, and Portunidae. The most dominant species of krustaseans were white shrimp (Penaeus merguiensis) as much as 25.06%, hermit crab (Clibanarius sp.) as much as 10.85%, and Uca annulipes as much as 10.59%. The fewest species of krustaseans found were Varuna yui of 0.13% and Ocypode sp. as much as 0.26%. The abundance value was 25.4 ind / m2, indices of diversity 2.60, richess index 0.87 and index of dominance 0.18.

Sea horse (Hippocampus kuda) is one of the ornamental marine organisms and raw material of traditional medicine. Since 1993, Seafarming Development Centre, Lampung has pioneered a research and  culture  of sea horse in Indonesia. The serious problem in the culture of sea horse is pathogenic bacteria caused death of juveniles and broodstocks. The objective of this study was to identify pathogenic bacteria isolated from  sea horse in Seafarming Development Centre. Koch Postulate test was carried out, and then the pathogenic bacteria were identifed by morphological and biochemical tests. Results showed that from a total of 6 bacterial strains isolated from diseased sea horse, 3 strains were pathogenic bacteria to sea horse. These 3 pathogenic bacteria caused identical disease signs with the initial disease signs when the bacteria were isolated.  Morphological and biochemical tests suggested that  the pathogenic bacteria could be identified to be Vibrio fluvialis, V. alginolyticus and V. hollisae.