Judul: Makanan dan Kebiasaan Makan Ikan Red Devil serta Peluangnya sebagai Ikan Invasif terhadap Biota Perairan di Situ Gede Bogor
Abstrak: Ikan red devil (Amphilophus labiatus) merupakan spesies asing invasif yang berasal dari Kosta Rika dan Nikaragua Amerika Tengah. Introduksi ikan red devil terjadi di beberapa perairan Indonesia, salah satunya Situ Gede Bogor. Penelitian ini bertujuan untuk menganalisis makanan dan kebiasaan makan dari ikan red devil serta peluangnya sebagai ikan invasif terhadap biota perairan di Situ Gede Bogor. Penelitian dilakukan pada bulan Ferbruari hingga Mei 2023. Analisis data yang digunakan yaitu Indeks Relatif Penting (IRP), luas relung, tumpang tindih makanan, dan biometrik organ yang berkaitan dengan kebiasaan makan ikan. Hasil penelitian menunjukkan ikan red devil memiliki makanan utama berupa krustasea (IRP=54,37-76,08%) dengan komposisi tertinggi pada sore hari di Stasiun 3 (outlet). Ikan red devil jantan dan betina merupakan omnivora-karnivora generalis dengan nilai luas relung 1,4151 dan tumpang tindih 0,9724. Ikan red devil merupakan ikan nokturnal yang aktif mencari makan pada waktu sore hari. Ikan red devil berpeluang menjadi ikan invasif di perairan Situ Gede Bogor dan menjadi kompetitor utama bagi ikan patin serta lele yang juga merupakan ikan omnivora-karnivora nokturnal., Red Devil fish (Amphilophus labiatus) is an invasive alien species from Costa Rica and Nicaragua Central America. The introduction of red devil fish populations have occurred in several Indonesian waters, one of which is Situ Gede Bogor. This study aims to analyze food and feeding habits of red devil fish and its potential as an invasive fish against aquatic biota in Situ Gede Bogor. The research was conducted in February until May 2023. Data analysis used in this research were Index of Relative Importance (IRI), niche breadth, niche overlap, and food-related biometrics organ related to feeding habits. The results showed that the red devil fish main diet consisting of crustacean (IRI=54,37-76,08%) with the highest composition in the afternoon at Station 3 (outlet). Male and female red devil fish are generalist omnivores-carnivores with a niche breadth value of 1.4151 and an overlap of 0.9724. Red devil fish are a nocturnal fish that actively forage in the afternoon. Red devil fish has the potential to become an invasive fish in the waters of Situ Gede Bogor and become a major competitor for catfish and pangas catfish which are also a nocturnal omnivorous-carnivorous fish.
Keyword: feeding habit, invasive, red devil fish, Situ Gede Bogor

Judul: The Status Stock of Red Bigeye (Priacanthus macracanthus Cuvier, 1829) in Palabuhanratu Bay, Sukabumi
Abstrak: Ikan swanggi (Priacanthus macracanthus) merupakan salah satu sumberdaya perikanan yang didaratkan di Pelabuhan Perikanan Nusantara (PPN) Palabuhanratu. Penelitian ini bertujuan mengkaji status stok ikan swanggi yang ditangkap nelayan di Teluk Palabuhanratu, Sukabumi. Contoh ikan diperoleh dengan metode Penarikan Contoh Acak Sederhana (PCAS) dari bulan September 2021 hingga Februari 2022. Hasil penelitian menunjukkan ikan swanggi betina lebih dominan daripada ikan swanggi jantan. Koefisien pertumbuhan (K) ikan jantan dan betina adalah 0,76 dan 0,65. Laju eksploitasi (E) ikan jantan dan betina adalah 0,63 dan 0,54. Ikan swanggi jantan dan betina memiliki ukuran pertama kali tertangkap (Lc) dan ukuran pertama kali matang gonad (Lm) sebesar 214,34 mm; 180,03 mm dan 243,50 mm; 191,50 mm yang menunjukkan growth overfishing. Model Fox dipilih dari beberapa model dengan koefisien determinasi (R2) sebesar 61,15. Status stok ikan swanggi berdasarkan data aktual 2020 termasuk under fishing. Maximum sustainable yield biomass (BMSY) ikan swanggi jantan dan betina sebesar 6% dan 15% yang menunjukkan recruitment overfishing., Red Bigeye (Priacanthus macracanthus) is one of the landed fishery resources in Nusantara Fishing Port (PPN) Palabuhanratu. This research aims to find out the status stock of red bigeye caught by a fisherman in Palabuhanratu Bay, Sukabumi. Fish samples were carried out using the Simple Random Sampling (SRS) method from September 2021 until February 2022. The results showed that red bigeye females were more dominant than males. Male and female growth coefficients (K) are 0,76 and 0,65. The exploitation rates (E) of males and females are 0,63 and 0,54. The males and females had the length of first caught (Lc) and length of the first maturity (Lm) were 214,34 mm; 180,03 mm and 243,50 mm; 191,50 mm which indicates growth overfishing. The Fox Model was selected from several models with a determination coefficient (R2) is 61,15. Red bigeye stock status based on actual data in 2020 was categorized as under fishing. The maximum sustainable yield biomass (BMSY) of Redbigeye males and females is 6% and 15% indicating that had been recruitment overfishing.
Keyword: Assessment, Management, Overfishing, PPN Palabuhanratu, Red Bigeye

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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