INTRODUKSI LAMPU CELUP PADA PENGOPERASIAN JARING INSANG HANYUT

Peluang keberhasilan operasi penangkapan ikan dengan jaring insang hanyut sangat ditentukan oleh arah ruaya ikan terhadap posisi jaring. Ikan akan tertangkap jika arah renangnya terhadang oleh jaring. Penelitian mencoba meningkatkan peluang ikan tertangkap dengan memanfaatkan lampu celup. Tujuannya untuk menunjukkan bahwa penggunaan lampu celup akan meningkatkan jumlah ikan hasil tangkapan tanpa mengurangi komposisi jenisnya. Dua unit jaring insang dioperasikan secara bersamaan. Salah satu unit jaring insang dilengkapi dengan lampu celup. Hasil penelitian menunjukkan penggunaan lampu celup tidak mempengaruhi komposisi jenis ikan yang tertangkap, tetapi hanya mempengaruhi jumlah tangkapannya. Jumlah total ikan hasil tangkapan jaring insang yang dilengkapi lampu celup mencapai 3.521 ekor, atau 58,82% dari seluruh ikan hasil tangkapan, sedangkan jaring insang tanpa lampu celup sebanyak 2.465 ekor (41,18%). Rincian hasil tangkapan jaring insang yang dilengkapi lampu celup dan tanpa lampu celup adalah mackerel tuna (Euthynnus affinis) sebanyak 218 ekor dan 129 ekor, spanish mackerel (Scomberomorus commerson) (80; 50), needlefish (Tylosurus crocodilus) (7; 3), Indo-Pacific sailfish (Istiophorus platypterus) (4; 2), driftfish (Psenes cyanophrys) (2.838; 2.051), dan moonfish (Mene maculata) (374; 230). Kata kunci: high-brightness LEDs, jaring insang hanyut, komposisi jenis ikan, lampu celup

Biomimetics Design Optimization and Drag Reduction Analysis for Indonesia N219 Seaplanes Catamaran Float

Design optimization on the Indonesia N219 seaplane catamaran is necessary to provide better service to rural islands of Indonesia. This research aims at decreasing drag using a design based on biomimicry by imitating the hydrodynamic characteristics of sailfish (Istiophorus platypterus) for pontoon floats. The design is then validated using a numerical fluid test using ANSYS Fluent to see the reduction in drag due to the change from a conventional or Wipeline® 13000 design to a biomimetics adaptation design. Next, further optimization was carried out based on the adaptation design based on trim tests, clearance tests, and deadrise angle dimensions suitable for biomimicry designs at Froude number speeds of 0.4 to 0.7. The design results with the adaptation of biomimicry show that a change in the design with this optimization affects a drag reduction that reaches 30% of the total drag generated by the conventional design.

BILLFISH CATCHES FROM OCEANIC RECREATIONAL FISHING IN THE ROYAL CHARLOTTE BANK, BAHIA, BRAZIL

The aim of this study was to analyze the oceanic recreational fishing in the Royal Charlotte Bank, state of Bahia, Brazil. Only data from an oceanic recreational fishing operator based in the municipality of Canavieiras, southern Bahia, were used, from 2012 to 2017. Overall, 103 fish specimens were caught and released, during this period, belonging to the following species: Makaira nigricans, Kajikia albida, and Istiophorus platypterus. Fishery operations occurred from October to March, with the highest catch in number in December (56.3%). The largest annual catch was recorded in 2013, with 39 individuals. The catch per unit effort ranged from 1.0 to 1.4 fishes per trip, with the highest value in December. Even though data presented here are partial, they can help to establish a strategic scenario for the fishing sector in Bahia, along with data from other fishing sectors (artisanal, industrial, subsistence and scientific).

Molecular cytogenetics insights in two pelagic big-game fishes in the Atlantic, the tarpon, Megalops atlanticus (Elopiformes: Megalopidae), and the sailfish, Istiophorus platypterus (Istiophoriformes: Istiophoridae)

Some pelagic and usually large sized fishes are preferential targets for sport and commercial fishing. Despite their economic importance, cytogenetic data on their evolutionary processes and management are very deficient, especially due to logistical difficulties. Here, information for two of such charismatic species, the tarpon, Megalops atlanticus (Elopiformes: Megalopidae), and the sailfish, Istiophorus platypterus (Istiophoriformes: Istiophoridae), both with a wide Atlantic distribution, were provided. Cytogenetic data were obtained using conventional methods (Giemsa staining, Ag-NORs technique, and C-banding), base-specific fluorochrome staining and fluorescence in situ hybridization (FISH) with rDNA probes. Megalops atlanticus has 2n = 50 chromosomes, all acrocentric ones (NF = 50), while Istiophorus platypterus has 2n = 48 chromosomes, 2m + 2st + 44a (NF = 52). Megalops atlanticus populations from the South Atlantic and Caribbean share identical karyotypic patterns, likely associated with gene flow between them. In turn, I. platypterus presents karyotype similarities with phylogenetically close groups, such as Carangidae. The chromosomal characteristics of these species highlight their independent evolutionary paths. Additionally, the current data contribute to knowledge of new aspects of pelagic fish fauna and will support further comparative studies with congeneric species, clarifying evolutionary karyotype trends of these fish groups.

Oil gland and oil pores in billfishes: in search of a function

ABSTRACTBillfishes are well known for their distinctive elongated rostra, i.e. bills. The functional significance of billfish rostra has been frequently discussed and the recent discovery of an oil gland (glandula oleofera) at the base of the rostrum in swordfish, Xiphias gladius, has added an interesting facet to this discussion regarding the potential co-evolution of gland and rostra. Here, we investigated the oil gland and oil pores (through which the oil is brought to the skin surface) of four billfish species – swordfish, Atlantic blue marlin (Makaira nigricans), Indo-Pacific sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) – and provide detailed evidence for the presence of an oil gland in the last three. All four species had a high density of oil pores on the forehead which is consistent with the hypothesis of hydrodynamic benefits of the oil. The extension of the pores onto the front half of the rostrum in sailfish and striped marlin, but not in swordfish or blue marlin, suggests that the oil may have additional functions. One such function could be linked to the antibacterial and anti-inflammatory properties of the oil. However, the available evidence on predatory rostrum use (and hence the likelihood of tissue damage) is only partly consistent with the extension of pores on rostra across species. We conclude that the oil gland probably serves multiple, non-mutually exclusive functions. More detailed information on rostrum use in blue marlin and swordfish is needed to better link behavioural and morphological data with the aim of accomplishing a full comparative analysis.

Nuevos registros de peces para el área marina del Parque Nacional Sistema Arrecifal Veracruzano, suroeste del Golfo de México

Presentamos cinco nuevos registros de peces para el área marina del Parque Nacional Sistema Arrecifal Veracruzano, con evidencia fotográfica y se proveen los datos morfométricos y merísticos básicos: el miraestrellas Gillellus greyae (70.3 mm, Longitud total), el góbido Oxyurichthys stigmalophius (36 mm, Longitud total), el cochito manchado Canthidermis maculata (342.4 mm, Longitud total) y el pez vela Istiophorus platypterus (?1,800 mm, Longitud total) se distribuyen ampliamente en el Caribe; además del primer registro en el Golfo de México del lenguado manchado Bothus maculiferus (250 mm, Longitud total).