Effect of freshwater discharge from Namgang Dam on ichthyoplankton assemblage structure in Jinju Bay, Korea

The movement of fish eggs and larvae in bay and estuarine systems is affected by freshwater discharge. In this study, the assemblage structures of ichthyoplankton eggs and larvae were assessed for the first time in Jinju Bay, South Korea, to identify the spawning and nursery functions of the bay. Fish eggs and larvae and several environmental parameters were sampled monthly from April 2015 to March 2016 inside and outside of the bay. Within the bay we collected eggs and larvae from 25 and 35 species, respectively, indicating greater diversity than outside the bay, where we collected eggs and larvae of 20 and 28 species, respectively. Fluctuations in water temperature and salinity were larger inside than outside of the bay, and chlorophyll-a concentration was higher within the bay, likely due to discharge from the Namgang Dam, which causes water to flow from the inside to the outside of the bay. This process influences fish larva abundance, such that more larvae are found outside than inside the bay. We also found that 28 fish species use Jinju Bay as a spawning ground. For some species, the timing of egg and larva appearance differed inside and outside of the bay, suggesting that the timing of spawning may differ between the two environments.

Variasi dan Kelimpahan Larva Ikan di Desa Timbulsloko, Kecamatan Sayung, Kabupaten Demak The Variation and Abundance of Fish Larvae In Timbulsloko Village, Sayung Subdistrict, Demak Regency

ABSTRAK Perairan Timbulsloko merupakan kawasan pesisir yang padat aktivitas manusia, seperti penangkapan ikan dan kegiatan pertambakan, sehingga menyebabkan sumberdaya biota dan larva ikan dapat terganggu. Larva ikan merupakan fase ikan setelah telur menetas, dimana pembentukan organ tubuh belum terbentuk secara sempurna serta masih sangat lemah dan sangat tergantung dengan pergerakan arus. Penelitian ini bertujuan untuk mengetahui komposisi dan jenis serta kelimpahan larva ikan berdasarkan pasang surut yang terdapat di perairan Desa Timbulsloko, Kecamatan Sayung, Kabupaten Demak. Penelitian dilaksanakan pada bulan November sampai Desember 2018. Metode penelitian yang digunakan adalah survei dengan penentuan titik sampling secara purposive sampling yang dilakukan di 5 stasiun baik pada saat pasang dan surut. Hasil yang diperoleh menunjukkan bahwa jumlah larva ikan yang tertangkap sebanyak 1.106 individu terdiri dari 8 famili yakni: Ambassidae (510 individu), Chanidae (60 individu), Engraulidae (49 individu), Gobiidae (59 individu), Leiognathidae (54 individu), Lutjanidae (36 individu), Mugilidae (279 individu), Scatophagidae (59 individu). Larva famili Ambassidae merupakan larva yang paling banyak tertangkap, sedangkan larva yang tertangkap dengan jumlah paling sedikit ialah famili Lutjanidae. Hasil analisis regresi linear berganda didapatkan nilai koefisien korelasi (R) sebesar 0,841 dan koefisien determinasi (R2) sebesar 0,708. Hasil uji Independent-Sample T test tidak terdapat perbedaan yang nyata antara kelimpahan larva ikan saat pasang dan surut pada setiap stasiun maupun setiap pengulangan. Jumlah larva ikan pada saat pasang 600 individudan pada saat surut 506 individu. ABSTRACT Timbulsloko waters is coastal areas that are densely human activity, such as fishing and aquaculture. This activities can give impact to the biota resources and fish larvae. The fish larva is the phase of fish’s life cycle after the eggs hatch. In this phase, the formation of fish's organs is not yet fully formed, weak, and very dependent on the water movement. The objective of this study was to determine the composition, the type and the abundance of fish larvae based on tides that found in the waters of Timbulsloko Village, Sayung District, Demak Regency. This study was conducted from November to December 2018. This study used a survey by determining the sampling points using purposive sampling conducted at 5 stations in the high tide and low tide. The results showed that the number of fish larvae caught were 1.106 individuals consist of 8 families, such as: Ambassidae (510 individuals), Chanidae (60 individuals), Engraulidae (49 individuals), Gobiidae (59 individuals), Leiognathidae (54 individuals), Lutjanidae (36 individuals), Mugilidae (279 individuals), Scatophagidae (59 individuals). Ambassidae family larvae was the most caught larvae, while Lutjanidae family larvae was the least amount caught. The results of multiple linear regression analysis showed that the correlation coefficient (R) was 0,841 and the coefficient of determination (R2) was 0,708. The results of the Independent-Sample T-test showed that there was no significant difference between the abundance of fish larvae in the high tide and low tide from every station and repetition. The number of fish larvae is 600 individuals and 506 individuals in the high tide and low tide, respectively.

Fixed Point Acoustic Monitoring Investigation Report for Marine Biological Resources in an Open Water Channel of Taishan Nuclear Power Plant

To disclose changes of density of fish larva and other marine organisms in an open water channel before the open net interceptor, this acoustic monitoring point was determined in front of the first open net interceptor in the open seawater channel with considerations to monitoring functions of EK80 scientific echometer to various cold-source organism and the marine organism recovery efficiency of open net interceptor. The beam direction was perpendicular downward. Floating marine organism enters into the interceptor after passing through the acoustic beam, while the quantity of swimming fish larva into the interceptor is smaller under normal marine conditions since they have certain swimming ability.

Potential of Freshwater Fisheries as a Supporting Factor for Minawisata of Tasikmalaya

Cibunigeulis Village, Bungursari District, Tasikmalaya has a huge the potential for freshwater fishery cultivation and minawisata activities. The research objective is to determine the characteristics of the freshwater fisheries sector as a supporting capacity for minawisata activities. The method used in this research is quantitative descriptive method. The results showed the cultivation of fisheries activities have a carrying capacity of ideal nurseries such as ponds, labor, breeding, knowledge and capital. The stages to have a good cultivation are the preparation stage of the pond, fertilizing, spawning, and hatching stage of the eggs become fish larva. The next stages, are the magnification stage, the harvesting stage, the processing stage and marketing stage. If these stages can be managed well it will also produce a good product. The fish are the primary commodity for consumption needs both inside the city and outside the city. Some fish products include, carp, catfish, Nile tilapia fish, tilapia, silver catfish and other fish. in terms of Minawisata activities, the village can be developed for fishing activities, culinary and fisheries exhibitions

The Effect of Immersion Duration in Thyroxine Hormone on Growth of Snakehead Fish Larvae (Channa striata)

The aim of this research was to determine the best immertion duration to increase growth rate of snakehead fish larva. The research was conducted in Fish Breeding unit Batanghari Sembilan Indralaya, Kabupaten Ogan Ilir. This research used a Completely Randomized Design (CRD), with five treatments (0, 12, 24, 36, and 48 hours of immertion), with three replications. The parameters observed were growth, survival rate and water quality. The results of this research show that the highest growth rate found in the 24 hours of treatment with the average value of 0.17 g of weight and increase in length of 1.90 cm. The best survival contained in treatment of immersion for 36 hours with the average value of 71.67%.

IDENTIFIKASI JENIS DAN HUBUNGAN KELIMPAHAN LARVA IKAN DENGAN KUALITAS AIR DI DANAU RANAU, SUMATERA SELATAN

Identifikasi larva ikan seringkali sulit dilakukan. Belum tersedianya kunci identifikasi untuk spesies larva ikan di perairan umum daratan sehingga belum adanya pedoman untuk dapat mengidentifikasi spesies larva ikan secara morfologi maupun meristik. Penelitian ini bertujuan untuk mengidentifikasi spesies larva ikan melalui sekuen DNA sehingga menghasilkan data spesies yang lebih pasti dan hubungan kelimpahan larva ikan dengan parameter kualitas perairan di Danau Ranau, Sumatera Selatan. Lokasi pengambilan sampel identifikasi jenis dan kualitas perairan di enam stasiun di Perairan Danau Ranau, Sumatera Selatan. Hasil identifikasi dengan menggunakan sekuen DNA ditemukan sepuluh jenis larva ikan. Kesepuluh jenis larva ikan tersebut antara lain Rasbora argyrotaenia, Puntius tetrazona, Oreochromis mossambicus, Oreochromis niloticus, Gambusia affinis, Poecilia reticulata, Mystacoleucus marginatus, Channa striata, Trichopsis vittata, and Trichogaster trichopterus. Sekuen DNA kemudian disejajarkan dengan sekuen referen dari perpustakaan data bank gen untuk mengakar pohon dengan menggunakan program BLAST dari NCBI untuk menemukan identitas yang paling dekat keterkaitannya dengan sampel larva-larva ikan yang dianalisis. Hubungan filogeni spesies diantara takson larva-larva ikan di Danau Ranau berdekatan. Kondisi perairan di Danau Ranau tergolong baik untuk biota perairan seperti larva ikan. Kualitas air merupakan parameter yang menentukan kelimpahan larva ikan di Danau Ranau. Larva-larva ikan antar populasi memiliki jarak genetik yang dekat antar satu dengan yang lain. Kelimpahan larva ikan berkorelasi positif dengan turbiditas dan berkorelasi negatif terhadap parameter daya hantar listrik.Identification of fish larva is often difficult. The unavailability of key identification for fish larva species in inland waters so that there are no guidelines for identifying fish larvae morphologically or meristically. This study aims to identify fish larva species from the Ranau Lake waters, South Sumatra through DNA sequences to produce more definitive species data and relationship of abundance of fish larva and water quality of parameters in Ranau Lake waters, South Sumatera. The sampling location of species identification and water quality was six stations in Ranau Lake waters, South Sumatra. The results of the study found the identification of fish larva species using DNA sequence found ten types of fish larva obtained. The ten types of fish larva include Rasbora argyrotaenia, Puntius tetrazona, Oreochromis mossambicus, Oreochromis niloticus, Gambusia affinis, Poecilia reticulata, Mystacoleucus marginatus, Channa striata, Trichopsis vittata, and Trichogaster trichopterus. The DNA sequence was then aligned with the referent sequence from the gene bank data library to root the tree by using the BLAST program from NCBI to find the identity that was closest to the sample of fish larvae analyzed. The relationship of species phylogeny between the fish larva of fish larva in Ranau Lake is close together. Fish larva between populations have close genetic distance from one another. Water quality in Ranau Lake are good for aquatic biota such as fish larva. Water quality is a parameter that determines the abundance of fish larva in Ranau Lake. The abundance of fish larva was positively correlated with turbidity, whereas negatively correlated to conductivity parameters.

KELIMPAHAN, KOMPOSISI DAN SEBARAN LARVA IKAN DI LAUT SERAM, LAUT MALUKU DAN TELUK TOMINI (WPP 715)

Laut Seram, Laut Maluku dan Teluk Tomini secara ekologis berfungsi sebagai daerah pemijahan, asuhan dan tangkapan berbagai jenis sumberdaya perikanan. Mempelajari larva di wilayah ini sangat berguna untuk penerapan pengelolaan dan pemanfaatan sumber daya ikan yang lestari. Tujuan dalam studi larva ini adalah menganalisis kelimpahan, komposisi dan sebaran larva ikan ekonomis penting. Perolehan data dilakukan secara survai eksplorasi dengan sampling menggunakan bongo net dan wahana KR Baruna Jaya VII pada stasiun-stasiun, yang ditentukan secara “Systematic Cluster random sampling”. Hasil penelitian menunjukkan kelimpahan telur dan larva rata-rata di Laut Seram 4.041 ind/103 m3, di Teluk Tomini 1.978 ind/103 m3 dan di Laut Maluku 861 ind./103 m3. Pada Wilayah Pengelolaan Perikanan (WPP) 715 didapatkan 119 familia ikan. Komposisi larvae ikan ekonomis di Laut Seram adalah Carangidae 19 %, Scombridae 8 %, Labridae 8 %, Serranidae dan Lutjanidae 4 %, di Laut Maluku Carangidae 17 %, Labridae12 % , Mullidae7 %, Clupeidae 6 %, Scombridae dan Lutjanidae 4 %, di Teluk Tomini Labridae 16 %, Carangidae 12 %, Scombridae 5 %, Serranidae dan Clupeidae 4 % dan kontributor lainnya larva ikan kurang ekonomis. Larva ikan ekonomis di WPP 715 yang mempunyai sebaran habitat luas adalah Carangidae, Labridae, Scombridae, Clupeidae, Lutjanidae dan Serranidae, secara berurutan masing-masing dengan nilai konsistensi habitat 91,89 %, 89,19 %, 78,33 %, 70,27 %, 62,16 % dan 54,05 %. Larva ikan kurang ekonomis dengan penyebaran luas adalah Platycephalidae dan Creedidae dengan nilai konsistensi habitat 62,16 % dan 59,46 %. Di WPP 715 Carangidae merupakan larva ikan yang dominan dan mempunyai sebaran terluas/konsisten). Perairan WPP 715 merupakan daerah pemijahan berbagai jenis ikan. Seram sea, Mollucas sea and Tomini bay have fisiohidrographic function as spawning area, nursery area and fishing ground of various fish. Studying the larvae in this region is very useful for the implementation of the management and sustainable use. Interest in the study are the larvae; abundance, composition and distribution of economically important fish larvae. Acquisition of data exploration survey conducted by sampling using Bongo net and KR Baruna Jaya VII rides on the stations, which determined by “Cluster stratified random sampling”. The result showed the average abundance of eggs and larvae are 4.041 ind/103 m3 in Seram Sea, 1.978 ind/103m3 in the Tomini Bay and 861 ind./103 m3 in Mollucas Sea. In the Fishery Management Area (FMA) 715 have 119 familia of fish larvae. The Composition of economically fish larvae, in the Seram Sea include 19 % Carangidae, 8 % Scombridae, 8 % Labridae, 4 % Serranidae and 4 % Lutjanidae. Mollucas sea covers 17 % Carangidae, 12 % Labridae, 7 % Mullidae, 6 % Clupeidae, 4 % Scombridae and 4 % Lutjanidae. Tomini bay include 16 % Labridae, 12 % Carangidae, 5 % Scombridae, 4 % Serranidae and 4 % Clupeidae and others less economically fish larva. Economical fish larvae in FMA 715 which have broad habitat distribution are Carangidae, Labridae, Scombridae, Clupeidae, Lutjanidae and Serranidae, respectively with values of habitat consistency of 91.89%, 89.19%, 78.33%, 70, 27%, 62.16% and 54.05%. Fish larvae are less economical with wide spread are Platycephalidae and Creedidae with habitat consistency values of 62.16% and 59.46%.. In FMA 715 Carangidae is the dominant fish larva and has the widest / most consistent distribution. The waters of FMA 715 are spawning areas of various types of fish.