MARGA ENGRAULTDAE (FISHES) DI TELUK AMBON: DIVERSITAS, STRUKTUR UKURAN, DAN FAKTOR KONDISI

lkan pelagis kecil yang berlimpah di Teluk Ambon meliputi ikan-ikan dari marga Engraiidae. lkan Engraulidae dikenal sebagai ikan umpan dalam perikanan cakalang, di samping itu masyarakat juga menjadikannya sebagai ikan konsums

FEKUNDITAS DAN DIAMETER TELUR IKAN TERBANG DI PERAIRAN SELAT MAKASSAR DAN UTARA BALI

Fekunditas dan diameter telur ikan merupakan bagian dari studi reproduksi biologi perikanan. Aspek ini dikaji dari tiga jenis ikan terbang, yaitu Cheilopogon cyanopterus, Hirundichthys oxycephalus, dan Parexocoetus mento yang dikumpulkan dari hasil tangkapan nelayan dengan jaring insang hanyut di perairan Takalar (Selat Makassar) dan Pemuteran (Bali Utara). Jumlah contoh yang diamati 58 gonad ikan betina yang berada pada tingkat kematangan gonad III dan IV. Fekunditas tertinggidimiliki oleh Parexocoetus mento, namun rata-rata fekunditas tertinggi dimiliki oleh jenis Hirundichthys oxycephalus. Korelasi antara fekunditas dan panjang total ikan memiliki tingkat keeratan yang rendah, sedangkan korelasi antara fekunditas dan bobot gonad memiliki tingkat keeratan yang kuat. Distribusidiameter telur ikan pada ketiga jenis ikan terbang ini tidak menunjukan perbedaan yang signifikan, namun secara umum diameter telur pada tingkat kematangan gonad III (0,33-2,21 mm) lebih kecil dari pada tingkat kematangan gonad IV (0,45-2,36 mm). Penelitian ini memberikan indikasi bahwaterdapat variasi fekunditas dan diameter telur antar jenis ikan terbang, serta lokasi penangkapan ikan terbang yang dilakukan oleh nelayan lokal saat ini merupakan daerah pemijahan. Fish fecundity and egg diameter are essential aspects in the study of fishery biological reproductive. These two aspects were observed on three species of fyingfish Cheilopogon cyanopterus, Hirundichthys oxycephalus, and Parexocoetus mento which collected from fishermen caught used a drift gillnet in the waters of Takalar (Makassar Strait) and Pemuteran (north Bali). Numbers of samples examined were 58 gonads of flyingfish at the third (develop) and fourth (mature) maturity stages. The higest fecundity was in the gonad of Parexocoetusmento, however the highest of fecundity mean was in Hirundichthys oxycephalus. The correlation between fecundity and total length shows a weak relationship, however the correlation between fecundity and gonad weight show a strong relationship. Egg diameter of these three flyingfish species had no significant different, but generally egg diameter of develop gonad (0.33-2.21 mm) was smaller than the mature one (0.45-2.36 mm). This study indicates variability in fecundity and eeg diameter among flyingfish species. In addition, the fishing grounds also indicates spawing grounds

KEBIASAAN MAKAN IKAN TERBANG, Hirundicthys oxycephalus DAN Cheilopogon cyanopterus, DI PERAIRAN SELAT MAKASSAR

Aspek kebiasaan makan dan komposisi makanan dari 2 jenis ikan terbang, Hirundicthys oxycephalus dan Cheilopogon cyanopterus, yang tertangkap di perairan Selat Makassar, dipelajari selama bulan Maret sampai dengan Juli 2005. Hasil yang diperoleh menunjukkan bahwa jenis makanan Hirundicthys oxycephalus dan Cheilopogon cyanopterus adalah sama, yaitu copepoda (71,4 dan 68,7%) sebagai makanan utama. Sedangkan makanan tambahan ke-2 jenis ikan ini berupa algae (8,4 dan 12,0%), malacostraca (3,2 dan 3,1%), dan chaetognatha (6,8 dan 6,2%). Luas relung makanan ke-2 jenis ikan ini relatif kecil, berkisar antara 1,79 sampai dengan 2,16, memberikan indikasi bahwa ikan terbang selektif dalam memilih makanan. Selang tumpang tindih relung makanan yang relatif rapat, berkisar antara 0,87 sampai dengan 0,98 menunjukkan bahwa jenis makanan yang dimanfaatkan sama, dan dapat memicu ada persaingan dalam mendapatkan makanan, saat sumber makanan yang tersedia terbatas. This research was conducted during March to July 2005 to obtain the food compotitions of two species of the flying fishes are in Makassar Strait, i. e. Hirundicthys oxycephalus and Cheilopogon cyanopterus. The results show that the food of the flying fishes Hirundicthys oxycephalus and Cheilopogon cyanopterus is similar, which is copepods (71.36 and 68.75%) as the primary food. The additional foods are algae (8.4 and 12.0%), malacostraca (3.2 and 3.1%), and chaetognatha (6.8 and 6.2%). Niche breath of flying fishes is narrow from 1.79 to 2.16, that means flying fishes are selective in collecting their foods. Niche overlap of the flying fishes is narrow from 0.87 to 0.98, it shows that the foods are similar and can cause a competition when the food source is limited

STRATEGI REPRODUKSI IKAN TERBANG (EXOCOETIDAE) DAN KAITANNYA DENGAN FAKTOR OSEANOGRAFI DI PERAIRAN INDONESIA

Ikan terbang (Excoetidae) memiliki strategi reproduksi yang diduga terkait dengan kondisi lingkungan perairan laut, seperti suhu, salinitas, angin, curah hujan, dan radiasi matahari. Penelitian dilakukan untuk 3 jenis ikan terbang (Hirundichthys oxycephalus, Cheilopogon cyanopterus, dan C. Spilopterus) selama tahun 2004 sampai dengan 2007 di perairan Indonesia. Hasil penelitian memperlihatkan bahwa ikan terbang (Excoetidae) memiliki peluang untuk memijah sepanjang tahun, dengan puncak pemijahan agak berbeda antar jenis maupun lokasi. Ada indikasi bahwa kecenderungan strategi pencapaian puncak pemijahan ikan terbang (Excoetidae) sangat dipengaruhi kondisi oseanografi, terutama suhu dan salinitas. Peristiwa upwelling yang secara periodik berlangsung selama musim timur (bulan Juni sampai dengan Agustus) di Laut Flores dan selatan Jawa diperkirakan sebagai faktor pemicu proses pemijahan ikan terbang (Excoetidae), sedangkan pola arus north equatorial di Laut Sulawesi sebagai faktor oseanografi yang mempengaruhi siklus reproduksi ikan terbang (Excoetidae). Pembuktian yang otentik lewat penelitian yang lebih komprehensif sangat diperlukan untuk mengungkapkan hal ini. Informasi ini akan sangat berguna untuk menyusun konsep kebijakan pengelolaan perikanan ikan terbang (Excoetidae) di Indonesia.  Reproductive strategy of flyingfish (Exocoetidae) relate to like temperature, salinity, wind, rainfall, and solar radiation. Three species of flyingfish (Hirundichthys oxycephalus, Cheilopogon cyanopterus, and C. Spilopterus) had been observed from 2004 to 2007. The results show that those fishes spawn throughout a year, with the spawning peak differed slightly among species and locations. However, seemingly the spawning peaks associated to the oceanographic conditions, especially temperature and salinity. Reproductive strategic of flyingfish would be generated by decreased temperature. In Flores sea and south of Java, upwelling occurs during the southeast monsoon (June until August), and this event creates low temperature. Whereas in Sulawesi Sea, the decrease of sea surface temperature occurs due to the north equatorial current. A valid evidence from comprehensive study is required to proof the phenomena. This information is valuable to develop a management plan for flyingfish fishery in Indonesia

STOCK STRUCTURE OF FLYING FISH (CYPSELURUS POECILOPTERUS) IN THE EASTERN INDONESIA WATER BASED ON MORPHOMETRIC AND MERISTIC VARIATION

Flying fish Cypselurus poecilopterus is a small pelagic fish resource that plays an important ecological and economic role. However, information regarding the structure of its stock in East Indonesian waters is still limited. This study aims to identify stock structure based on morphometric, meristic approaches, and associated with environmental factors. Fish samples were taken during one fishing season (June-September) in 2015 and 2021 in the waters of West Papua and East Seram where the Lydakker line passes, using the method of observation and purposive sampling, then the data were analyzed descriptively and t-test. The results of observations on 23 morphometric characters and 5 meristic features showed a significant difference, so it is estimated that flying fish stocks are composed of 2 sub-populations. Differences in morphometric and meristic parameters are affected by different environmental conditions in the two waters. This information is expected to be useful for the management and sustainable use of flying fish resources

MIGRASI VERTIKAL ZOOPLANKTON DI LAUT BANDA

Analisis migrasi vertikal zooplankton di Laut Banda telah dilakukan berdasarkan nilai hambur balik akustik yang diperoleh dari pengukuran pada tanggal 21-30 November 2013 menggunakan instrument akustik simrad EK 500 yang dipasang pada Kapal Riset Baruna Jaya VII. Hasil analisis menunjukan migrasi vertikal zooplankton di Laut Banda merupakan fungsi dari waktu dan konsentrasi klorofil. Agregasi zooplankton berada pada lapisan permukaan 0-25 meter untuk setiap waktu pengamatan, bersamaan dengan nilai konsentrasi khorofil yang tinggi yakni mencapai 2,1 mg/m3. Nilai volume hamburan balik akustik rerata pada strata kedalaman 0-25 meter adalah -84,31 dB, pada kedalaman 25-50 meter sebesar -82,02 dB dan pada kedalaman 50-75 meter sebesar -83,9 dB

FISH SPECIES COMPOSITION IN SEAGRASS BEDS OF TANJUNG MERAH (NORTH SULAWESI), INDONESIA

Seagrass beds are found along the shore of Tanjung Merah (North Sulawesi, Indonesia). This ecosystem covers approximately 20 hectars, and are well known to support local fisheries. Thalassiahemprichii was the dominant seagrass species at the study site. This study in the given area was aimed to monitor any changes in fish assemblage structure, and examine the function of seagrass beds for marine fish. Fishes were sampled using the small beam trawl in March 2003, April 2004 and September 2005. A total of 137 species belonging to 34 families were identified. Twenty four species were found abundantly in terms of individual numbers, however Apogon margaritophorus and A. hartzfeldii were the most dominant. These two species were permanent resident, indicated by a catch of large number in different stages of life cycle. We also noticed that many adults of A. margaritophorus kept fertilized eggs in their mouths. This evidence also confirmed that seagrass beds function as both spawning and nursery ground for marine fishes. During three years’ monitoring, there was a slightly seasonal variety in fish assemblage structures

Keragaman Jenis dan Distribusi Ukuran Panjang Ikan Terbang di Perairan Indonesia Timur

Research on flyingfishes in 2004 was aimed to know their species diversity and length distribution. Two locations were selected as sampling sites such as Flores Sea and Sulawesi Sea. Samples were collected in Takalar from May to July 2004 represented samples from Flores Sea, and in Manado and Tahuna in November 2004 represented samples from Sulawesi Sea. All samples were caught by local fishermen who operated a gillnet. There were 7 species identified from Flores Sea, i.e. Cheilopogon abei, Cheilopogon spilonopterus, Cheilopogon spilopterus, Cheilopogon suttoni, Cypselurus poecilopterus, Hirundichthys oxycephalus and Parexocoetus mento, whereas from Sulawesi Sea, Cheilopogon cyanopterus and Cheilopogon spilopterus were identified. The average total length of C. spilopterus collected in May-July 2004 was longer than 200 mm and were no variation amongst months, while Cheilopogon spp. sampled from Sulawesi Sea was longer than 250 mm. The flyingfish samples were mostly in adult stage and had spawned