Low genetic diversity in Clarias macrocephalus Günther, 1864 (Siluriformes: Clariidae) populations in the Philippines and its implications for conservation and management

Main Article Content

Marc Timothy C. Tan
Joycelyn C. Jumawan
Jonas P. Quilang


Clarias macrocephalus Günther, 1864 is a Near Threatened freshwater catfish found in the Philippines and other Southeast Asian countries.  Its numbers have dwindled over the past few years because of habitat loss and competition.  This study examined the genetic diversity of the remaining viable populations of C. macrocephalus in the Philippines.  Primers were designed to amplify via polymerase chain reaction (PCR) the complete mitochondrial DNA (mtDNA) control region (870-bp) in 120 specimens collected from three sites: (1) Buguey, Cagayan; (2) Camalaniugan, Cagayan; and (3) Agusan del Sur.  Of the 120 sequences generated, only three haplotypes and two polymorphic sites were found. Overall haplotype and nucleotide diversity (h=0.479, π=0.00058) were alarmingly low, consistent with populations of other freshwater fishes that have experienced a genetic bottleneck.  The overall FST value was 0.80050, indicative of large genetic differentiation between populations.  The very low genetic variation found in all three C. macrocephalus populations calls for conservation and management efforts for the protection of the remaining populations of this economically important species.

Article Details

Author Biographies

Marc Timothy C. Tan, Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, Philippines

Marc Timothy C. Tan is a graduate of BS Biology at the University of the Philippines Diliman. During his undergraduate degree program, he worked on fish DNA barcoding and population genetics. He is currently taking up Medicine and Master in Business Administration at the Ateneo School of Medicine and Public Health, Ateneo de Manila University. 


Joycelyn C. Jumawan, Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, Philippines Caraga State University-Main Campus, Ampayon, 8600 Butuan City, Philippines

Dr. Joycelyn C. Jumawan is currently an Associate Professor at the Department of Biology, Caraga State University. Her research interest includes fish reproductive biology and genetics. She has been involved in biodiversity conservation research in Agusan Marsh.


Jonas P. Quilang, Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, Philippines

Dr. Jonas P. Quilang is an Associate Professor and Head of the Molecular Population Genetics Laboratory at the Institute of Biology, University of the Philippines Diliman. His research interest includes molecular phylogenetics, molecular population genetics, and DNA barcoding of Philippine fishes.



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