Gonad Maturity and Fecundity of Bluecheek Silver Grunt (Pomadasys argyreus) in Palabuhanratu Bay, West Java

A total of 806 fish samples were collected from the catch of local fishermen. The sex ratio of Pomadasys argyreus was 1:0,90. Four stages of gonadal development were observed in males and females, which dominated by stage I and II (immature). The highest gonadosomatic index (GSI) in males was 1,14 in September, while in females was 1,80 in May. Length at first maturity of Pomadasys argyreus was 140,12 mm for males and 135,01 mm for females. The highest value of condition factor was 1,05 for males and 1,10 for females. This fish spawn partially (partial spawner) and estimated spawns throughout the year with a spawning peak in June.

Growth, mortality and yield of Sarotherodon melanotheron melanotheron (Rüppell, 1852) in the Lake Nokoué and Porto-Novo Lagoon complex Benin, West Africa

The study evaluated some population parameters of Sarotherodon melanotheron melanotheron within a lagoon complex in southern Benin: Lake Nokoué and Porto-Novo Lagoon. Data on the total length, total weight, and sex were recorded monthly between January and December 2015 for 1,745 specimens captured by local fishermen. The asymptotic length L∞ was estimated at 24.68 cm. The growth rate K was 0.86. The total, natural, and fishing mortalities were estimated at 2.46, 1.71, and 0.75 y−1, respectively. The size at first sexual maturity was 8.9 and 9.2 cm, respectively, for males andfemales. The size at first capture was estimated at 9.2 cm, which indicates that fish spawn at least once before capture. The current exploitation rate of 0.31 remains below the maximum exploitation rate Emax which was 0.604 but was equal to the exploitation rate retaining 50% of the biomass of the stock (E0.5 = 0.324). This suggests that the stock of S. m. melanotheron is not overexploited in the complex. However, it is recommended that the actual rate of exploitation be kept as it is to ensure a sustainable management of these fish populations.

Mengenal ikan sepatung (Pristolepisgrootii), spesies asli Indonesia kandidatkomoditi akuakultur

Indonesian leaf fish (Pristolepisgrootii), is Indonesia endogenous fish species. This species is native in open-freshwater on the islands of Sumatra and Kalimantan.The purpose of this paper is to determine the aspects of bioecology, processed fish products and disseminating information related to Indonesian leaf fish.Data collection methods through surveys, laboratory observations and literature studies.The data collected consists of primary data and secondary data.The results of observations and analysis showed that the Indonesian leaf fish are near families to climbing perch fish (Anabas testudineus), gouramy (Osphronemusgoramy), kissinggouramy fish (Helostomatemminckii).Local names are diverse, the national name of the sepatung fish and the international name are Indonesian leaf fish.Indonesian leaf fish habitat in fresh water. This fish is an omnivore, euryphagic.The morphological differences of male and female fish are not clear, sexual dimorphism is not apparent.Sex ratio in the wild in a balanced condition.Indonesian leaf fish spawn season at the rainy season. This fish can be processed into a variety of menu, and can be preserved by salted, fogged and fermented.Indonesian leaf fish has biological superiority and economic value, so it is worthy of being a candidate for aquaculture commodity.Keywords: bioecology, Indonesian leaf fish, sepatung fish, native Indonesian fish, Pristolepisgrootii AbstrakIkan sepatung (Pristolepisgrootii), merupakan salah satu jenis ikan endogenous Indonesia. Ikan ini native di perairan umum air tawar di pulau Sumatera dan Kalimantan. Tujuan penulisan ini adalah untuk mengetahui aspek bioekologi, harga, produk olahan ikan sepatung dan menyebarluaskan informasi yang terkait dengan ikan sepatung. Metode pengumpulan data melalui survey, pengamatan laboratorium dan studi literatur. Data yang dikumpulkan terdiri data primer dan data sekunder. Dari hasil pengamatan dan analisa, ikan sepatung berkerabat dengan ikan betok (Anabas testudineus), ikan gurami (Osphronemusgoramy), ikan tembakang (Helostoma temminckii). Nama lokalnya beragam, nama nasional ikan sepatung dan nama internasionalnyaIndonesian leaf fish. Habitat hidup ikan sepatung di air tawar. Ikan ini termasuk jenis ikan omnivore, bersifat euryphagic. Perbedaan morfologi ikan jantan dan betina tidak jelas, dimorfisme seksual tidak tampak. Sex ratio ikan sepatung di alam bebas dalam kondisi seimbang. Ikan sepatungmemijah pada awal musim penghujan. Ikan ini dapat diolah menjadi berbagai menu masakan, dan dapat diawetkan dengan penggaraman, pengasapan dan fermentasi. Ikan sepatung memiliki keunggulan biologi dan bernilai ekonomi, sehingga layak menjadi kandidat komoditi budidaya perikanan. Kata kunci:bioekologi, Indonesia leaf fish, ikan sepatung, ikan asli Indonesia, Pristolepisgrootii,

When Do Mountain Whitefish (Prosopium williamsoni) Spawn? A Comparison of Estimates Based on Gonadosomatic Indices and Spawner and Egg Counts

Determining when fish spawn has major implications for effective fisheries management, particularly in dam-controlled rivers where reproductive potential may be affected by an altered hydrograph. Three methods for estimating spawn timing in riverine broadcast spawners were compared for their precision, effort and potential impact on a population of Mountain Whitefish in the regulated Lower Duncan River, Canada. The first method is based on the Gonadosomatic Index (GSI), which is a measure of the relative mass of an individual’s gonads. The second method is based on counts of aggregating adults, while the third method is based on passive egg collection using egg mats. Analysis of the GSI data provided the most precise estimates. It estimated that spawning occurred between October 30th and November 26th in 2010 and between November 8th and November 27th in 2011. Collection of GSI data required moderate effort and had some impact due to the need for lethal harvest. Analysis of the spawner counts using a simple Bayesian Area-Under-the-Curve model provided less precise estimates of spawn timing but the method likely had negligible impact on the population and required only moderate effort. Deployment of egg mats required high effort and collected insufficient information to derive statistical estimates of spawn timing. We discuss how information from different methods could be combined together into a single integrated model to maximize the precision while minimizing the effort and impact.

Evolving Sustainable Green Ship Technology

Man lives in two worlds, the biosphere and the techno-sphere. Over the years, time needs, growth, speed, knowledge, and competition have created demand that necessitated man to build complex institutions. Ship design is not left out of this process. Inland waters are under threat from untreated waste that can feed bacteria and algae, which in turn exhaust the oxygen. The ocean, the seas, and fresh water together cover the largest percentage of planet earth. Many think that everything that runs into it is infinite; the ocean is providing the source of freshening winds and current that is far more vulnerable to polluting activities that have run off too many poisons into them. The ocean may cease to serve these purposes if care is not taking to prevent pollution. The issue of the environment has become so sensitive recently and is linked to infrastructure development work. In the maritime industry, polluting activities from oil bilge to ballast pumping has turned into poison and has an adverse effect on water resources. Some have choked too much estuarine water where fish spawn. In a nutshell, the two worlds of man are currently are out of balance and in potential conflict. Man is in the middle, and since the threats are mostly water related, ships are in the middle too. Historical records of a number of calamities that have resulted in heavy loss and pollution call for environmentally sound ships. This has led to a number of regulations that will subsequently affect policy change and procedure interaction with the system. The current situation has an effect on the design of new ships and modification of existing ships. This chapter discuss regulations design, with an emphasis on new system design drive towards processing waste and emissions on board so that discharges are acceptable. The chapter hopes to give insight into need, response, and research directions for green ship technology.