Judul: Analisis perikanan cakalang (Katsuwonus pelamis) di Teluk Bone : hubungan aspek biologi dan faktor lingkungan
Abstrak: Fishing activities targeting skipjack tuna (Katsuwonus pelamis) take place in the Bone Bay. The bay is part of the Indonesia Fisheries Management Area or WPPI 713 that covers Makassar strait, Flores sea and Bali sea. This study describes some biological characteristics of the skipjack tuna in three pre-defined fishing zones, i.e. the North Zone (Districts of Luwu, Luwu Utara, Luwu Timur, Wajo and Palopo city), the Centre Zone (District of Bone) and the South Zone (District of Sinjai). Such information is very important for developing fisheries management strategies in the bay. The objectives of the study are to analyze biological characteristics of the skipjack tuna caught in the Bay, to calculate and interpretate of CPUE of the fisheries, to analyze dynamics of fishing and fish production in relation to oceanography condition, and to determine a concept of fisheries management of the Bone Bay. Data were obtained from fishing activities conducted by local fishermen from January to December 2007, local fisheries statistics and internet-published data of sea surface temperature (SST) and chlorophyll (Chl) content. Seasonal and annual total fishing effort and fish production for a period of 11 years (1996-2006) were analyzed. Seven statistical parameters of the factors for SST and Chl were calculated and correlated with the fisheries statistics. The b coefficients for length-weight relationship in the three zones were equal to 3. The average fork-length (FL) of the fish in each zone showed similar trends, i.e it increased from January to June, then stabilized until December. Using von Bertalanffy’s growth model, the maximum FL (i.e.,76 cm) will be reached when fish at age of 84 months while the length at first maturity of the fish is 46,5 cm (FL). Overall, the average size of the skipjack tuna caught by pole and liners in January-April are small (31,5-46,3 cm, FL), from May to June the fish is larger (48,5-56,6 cm, FL), then the average size become smaller from July to December (33,7-48,2 cm, FL). From January to May, the size of the fish in the North Zone is generally smaller than in the two other zones. From May to August, the size of the fish in the South Zone is generally larger than in the two other zones. From September to December the size of the fish is generally similar among the three zones, but smaller than the size of the fish caught in the South Zone in June. Regardless of fish size composition, the MSYSS of Bay-wide shared fish stock is 15.783 tons/year with Fopt is 12.626 trips/year. However, considering length at first maturity of the species, the catch allocation for the North Zone should be 573 tons/year with fishing effort of 409 trips/year, catch in the Center Zone should be 5.820 tons/year with fishing effort of 3.279 trips/year, while in the South Zone should be 2.210 tons with fishing effort of 1.688 trips/year. The relationship between fish production and SST/Chl, for both seasonal and quarterly in the North, Central and South Zones were categorized as type 11, 10 and 5, respectively. Significant correlations were identified between SST/Chl and production of
Keyword: Katsuwonus pelamis, Overfishing, Renewable resources, Spawning ground, Nursery ground, Feeding ground, Skipjack tuna, Fisheries management, Shared fish stock, Fishing zone, Bone Bay

Judul: Resource Management of Skipjack (Katsuwonus pelamis) in Pelabuhanratu, Sukabumi District, West Java
Abstrak: Katsuwonus pelamis (skipjack or Skipjack Tuna) is one of the major pelagic fish commodities in Palabuhanratu Archipelagic Fishing Port (PPN Palabuhanratu) and become important aspect in the development of fisheries industrialization especialy for non-tuna species. Geographically, Palabuhanratu bay is situated in Fisheries Management Area (WPP) 573 on Indian Ocean. As the vast waters, fisheries management can be initiated from a small area, for example in the bay area. To understand the biological characteristics of fish such as skipjack (Katsuwonus pelamis Linnaeus, 1758) is crucial information to realizing fisheries resources management in some region. This research aims to determine the weight and length relationship, size composition, growth pattern and decent size of skipjack fishing in Palabuhanratu. Data obtained from the result of landing catches in PPN Palabuanratu from December 2012 to May 2013. Through a series of data catches of skipjack during the period 2002 to 2011 estimation made for catch effort at the level of Maximum Sustainable Yields (MSY), Maximum Economic Yield (MEY) and Open Access (OA). MSY, MEY and OA are the bio-economic indicator to formulate appropriate policies for Skipjack resources management in Palabuhanratu. The research was conducted on fish landed in Palabuhanratu by using payang gear, gillnet, and trolling. From the results of the calculation of the weight and length noted that males skipjack have a negative allometric growth pattern which means that its length growing faster than its weight. While skipjack females have an isometric growth which means its length growth pattern equal to its weight. The maximum length of tuna were obtained during the study was 710 mm. Length of fish for the first gonads mature was estimated of 523 mm, with the result that so the tuna catch is a the minimum worthines of cakalang fishing was 523 mm. Recognizing these data, if compared with the size of tuna caught during the study, only 11.2 % were larger than the size of a decent catch, this is an indication of the outset of the recruitment overfishing in Palabuhanratu. Total males mortality rate (Z) was 2.0988 fish per year and for females amounted to 0.8415 per year. While the rate of exploitation of both males and females are equal to 0.9 per year. The catch and effort at the level of Maximum Sustainable Yield (MSY) are 305.283 kgs /year and 3.898 trips /year. While estimating the value of the Maximum Economic Yield (MEY) and Open Access (OA) at the level 240.380 kgs/year; 2.101 trips/ year and 303.434 kgs/year ; 4.201 trips/year. Fox models analysis shows that overfishing has occurred since 2006 with the utilization rate of 129 % as calculated in the last year (2011) has undergone economic over fishing. Some forms of fisheries management proposed in this research include: restrictions on fishing quotas at MSY level of 78,32 Kgs/Trip and to MEY 114,43 Kgs/Trip; the policy of mesh size; conservation efforts; season control / fishing areas (spawning ground and fishing ground); rotation in fishing (fishing with alternate day) ; restrictions on the issuance of fishing licenses for new fishing vessels; Co-management among stakeholders; law enforcement (enforcement) and
Keyword: Pelabuhanratu Bay, Bioecological parameters, Bioeconomics, optimization, management.

Judul: Solusi Geometri Schwarzschild untuk Dimensi 4+1 dengan Invarian Rotasi Isotropik
Abstrak: Metrik Schwarzschild merupakan solusi eksak pertama dari persamaan medan Einstein dengan mangasumsikan metrik statik dan simetris. Metrik Schwarzschild yang ditemukan oleh Karl Schwarzschild masih dalam dimensi 3+1, namun seiring dengan teori-teori terbaru yang menunjukkan bahwa alam semesta tidak hanya di dimensi 3+1. Maka melalui penambahan dimensi, tujuan penelitian ini memperoleh solusi pada geometri Schwarzschild untuk dimensi 4+1 dengan memodifikasi koordinat bola yang invarian rotasi isotropik dan melalui penurunan rumus seperti koordinat bola, simbol Christoffel, dan tensor Ricci. Selain mendapatkan solusi ini, metrik Schwarzschild dimensi 4+1 dapat digunakan sebagai metrik dasar untuk memperoleh solusi blackhole dan wormhole pada dimensi 4+1. Hasil akhirnya, dengan memanfaatkan modifikasi koordinat bola, metrik Schwarzschild dapat dibentuk sehingga diperoleh solusi geometri Schwarzschild untuk dimensi 4+1.
Keyword: metrik Schwarzschild, persamaan medan Einstein, modifikasi koordinat bola, penambahan dimensi, invarian rotasi isotropik