STATUS KERAGAMAN IKAN BELIDA (Chitala spp.) DI SUNGAI TULANG BAWANG, PROPINSI LAMPUNG BERDASARKAN PADA KARAKTER MORFOMETRIK DAN INDEKS FLUKTUASI ASIMETRIK - Arif Wibowo; Tri Mas Djoko Sunarno; Subagdja Subagdja (Pusat Riset Perikanan, BRSDM KP., 2008)
Penelitian tentang status keragaman ikan Belida (Chitala spp.) dari Sungai Tulang Bawang berdasarkan pada karakter morfometrik dan indeks fluktuasi asimetrik dilakukan selama tahun 2005 di daerah aliran Sungai Tulang Bawang Propinsi Lampung. Estimasi keragaman berdasarkan pada karakter morfometrik dengan menggunakan nilai coefficient variation diperoleh dengan cara membagi standar deviasi karakter dengan rata-rata, pada 25 karakter morfometrik dari 26 spesimen ikan belida (Chitala spp.). Indeks fluktuasi asimetrik ikan belida (Chitala spp.) dari Sungai Tulang Bawang diestimasi menggunakan formula Palmer dan Strobeck, untuk kemudian melihat CVDI sebagai estimasi keragaman dengan terlebih dahulu melakukan analisis uji ttest untuk mengetahui signifikasi karakter sebelah kiri dan kanan. Klasifikasi nilai coefficient variation untuk karakter morfometrik CVd”25% = sangat seragam, 25%<CVd”50% = cukup seragam, 25 <CVd”50% = cukup bervariasi, dan CVe”75% = sangat bervariasi. Sedangkan nilai fluktuasi asimetrik digunakan indeks 3 tingkatan variasi yang rendah (CVDI=0,1), variasi sedang (CVDI=0,5), dan sangat bervariasi (CVDI=1). Berdasarkan pada nilai coefficient variation sebagian besar karakter morfometrik tergolong cukup seragam 72% (25%<CVd”50%) dan cukup bervariasi 28% (50 <CVd”75%), dengan rata-rata 47,60% tergolong cukup seragam. Berdasarkan pada indeks CVDI terlihat 60% karakter asimetrik tergolong variasi sedang dan sangat bervariasi (CVDI=0,5) dan CVDI=1), 40% termasuk variasi yang rendah. Hasil analisis karakter morfometrik dan indeks fluktuasi asimetrik mengkonfirmasi bahwa populasi ikan belida (Chitala spp.) di Sungai Tulang Bawang telah berada pada kondisi mendekati seragam atau memiliki variasi genetik yang rendah. Research on the status of knife fish (Chitala lopis) diversity in Tulang Bawang River (Lampung Province) based on morphometric charactes and indeks of fluctuating asimetric had been carried out during 2005 at Tulang Bawang River (Lampung Province). Diversity was estimated based on morphometric characters using coefficient variation values, which is derived from dividing the standard deviation characters by its mean, on 25 morphometric characters from 26 knife fish (Chitala lopis) specimens. Fluctuating asimetric indeks of knife fish (Chitala lopis) Tulang Bawang River were estimated using Palmer and Strobeck formula, and then see CVDI as the estimate of diversity, as previously conduct Ttest analysis to find signification character between the right and left of the body. Coefficient variation values derived on morphometric character classified four categories, CVd”25% = as highly uniform, 25%<CVd”50% = middle uniform, 25%<CVd”50% = middle variation, and CVe”75% = highly variation. Meanwhile fluctuating asimetric value employed three rate clasification, low variation (CVDI=0.1), middle variation (CVDI=0.5), and high variaton (CVDI=1). Based on coefficient variation value, most of the morphometric characters were middle uniform 72% (25%<CVd”50%) and middle variation 28% (50%<CVd”75%), with means value is 47.60% classified as middle uniform. Based on indeks CVDI shown 60% asimetric characters classified as variation middle and high variation (CVDI=0.5 and CVDI=1), 40% identified had low variation. Research confirms that knife fish (Chitala lopis) at Tulang Bawang river were in state of closing uniform or presumby have low genetic variation.