Judul: Biologi Reproduksi Ikan Layur (Trichiurus lepturus Linnaeus, 1758) di Teluk Palabuhanratu, Sukabumi. Jawa Barat
Abstrak: Ikan layur merupakan salah satu ikan yang memiliki nilai ekonomis penting dan telah menjadi komoditas ekspor. Permintaan yang terus meningkat menyebabkan peningkatan upaya penangkapan yang dapat mengancam ketersediaan sumberdaya ikan layur. Penelitian ini bertujuan menganalisis aspek biologi reproduksi ikan layur di Teluk Palabuhanratu. Penelitian dilaksanakan pada bulan Mei hingga September 2017. Pengambilan ikan contoh menggunakan metode penarikan contoh acak sederhana. Ukuran ikan layur yang diteliti sebanyak 639 ekor dengan nisbah kelamin antara jantan dan betina sebesar 1:2,20 atau didominasi ikan betina. Potensi reproduksi ikan layur betina tergolong tinggi dengan rata-rata 13 018 butir telur. Musim pemijahan ikan layur diduga terjadi selama periode pengamatan dan puncak pemijahan terindikasi terjadi pada bulan Juni dengan tipe pemijahan partial spawner. Ikan layur jantan mencapai ukuran pertama kali matang gonad (Lm) lebih awal dibandingkan dengan ikan layur betina, yaitu pada ukuran 641,37 mm untuk jantan dan 755,28 mm untuk betina.
Keyword: ikan layur (Trichiurus lepturus), musim pemijahan, potensi reproduksi, Teluk Palabuhanratu

Judul: Biologi Reproduksi Ikan Layur (Trichiurus lepturus Linnaeus, 1758) dan Pengelolaannya di Perairan Selat Sunda.
Abstrak: Ikan layur (Trichiurus lepturus) merupakan bagian dari ikan bentopelagis yang tertangkap menggunakan payang di perairan Selat Sunda. Penelitian ini bertujuan untuk mengkaji aspek biologi reproduksi dan sosial ekonomi. Penelitian ini berdasarkan pengambilan data primer yang pada bulan Mei-September 2016 dengan pengambilan contoh sebanyak lima kali dilakukan setiap 30 hari. Jumlah ikan layur yang diambil sebanyak 874 ikan, diantaranya 558 ikan jantan dan 316 ikan betina. Hasil penelitian ini menunjukkan bahwa rasio ikan layur tidak seimbang, rasio jantan dan betina sebesar 1:0,57. Ukuran pertama kali matang gonad ikan jantan dan betina masing-masing adalah 398,53 mm dan 444,40 mm. Musim pemijahan ikan layur terjadi pada bulan Mei sampai Juli dengan puncak pemijahan pada bulan Mei, dan tipe pemijahan terindikasi bersifat total spawner. Potensi reproduksi ikan layur dapat dikategorikan cukup tinggi dengan kisaran fekunditas 425-454 235 butir. Harga ikan layur yang dilelang di Labuan berkisar antara Rp 9 000 sampai Rp 32 000 per kg. Ikan layur bereproduksi untuk mempertahankan jenis dan populasinya juga merupakan komponen penting dalam dinamika populasi ikan.
Keyword: Biologi reproduksi, ikan layur, Selat Sunda

Judul: Glucose biosensor using a glucose dehydrogenase flavin adenine dinucleotide electrochemically immobilized on zeolite nanoparticles
Abstrak: A glucose biosensor was developed to measure blood glucose levels. The performance of these new glucose biosensors was continuously improved, producing better performance and stability. The technique selection and immobilization matrix are key factors for biosensor development, so that the prospecting of materials that can be used as a matrix for supporting enzyme, continue to be explore. The purpose of this study was to determine the activity and stability of the enzyme glucose dehydrogenase (GDH) that were immobilized on zeolite nanoparticles (NPZ) and determine the kinetic parameters and analytical performance by electrochemical methods. The resulting enzyme electrode with NPZ and enzyme electrode with zeolite A showed a high activity against the enzyme electrode glucose than without NPZ. The reaction kinetics of third electrodes of enzyme followed the Dixon equation. The 𝐼����𝑚����𝑎����𝑥����𝑎����𝑝����𝑝���� values for enzyme electrode without NPZ, with NPZ, and with zeolite A were 27.25 μA, 77.52 μA, and 48.54 μA, respectively. The 𝐾����𝑀����𝑎����𝑝����𝑝���� values for GDH enzyme that immobilized on the NPZ were 1.16 mM, 12.30 mM for GDH enzyme that immobilized on zeolite A and 0.95 mM for GDH enzyme immobilization without NPZ. The enzyme electrode without NPZ, with NPZ, and with zeolite A also showed a high sensitivity with value for the sensitivity were 0.58 μA mM-1, 0.81 μA mM-1, and 2.51 μA mM-1, respectively. The third enzyme electrodes showed different linear area with range for the enzyme electrode without NPZ, with NPZ and with zeolite A were 1.00-15.00 mM, 2.00-20.00 mM, and 0.06-10.00 mM, respectively. The blood glucose level of normal person ranged from 4 to 6 mM, so that the enzyme electrode with NPZ and without NPZ are suitable for use in the determination of the concentration of blood glucose. While the enzyme electrode with zeolite A has a smaller range so it is more suitable to use in the determination of glucose concentration in the foods or beverages. The enzyme electrode with NPZ and the enzyme electrode with zeolite A showed a good accuracy with relative error values were 3.84% and3.48%, respectively. Repeatability measurements also showed a good precission results with relative standard deviation values (%RSD) for the enzyme electrode with NPZ and enzyme electrode with zeolite A were 3.83% and 3.16%, respectively. By combining two immobilization techniques, physical adsorption on zeolite and entrapment on carbon paste, high enzymatic activity, good accuracy, and repeatability was attained. The enzyme electrode with NPZ and the enzyme electrode with zeolite A demonstrated a good electrochemical response toward glucose, allowing it to detect blood glucose levels and glucose levels in foods and beverages.
Keyword: glucose biosensor, immobilization, zeolite