Evidence of shallow mitochondrial divergence in the slender armorhead, Pentaceros wheeleri (Pisces, Pentacerotidae) from the Emperor Seamount Chain

Abstract

Competitive overexploitation of the slender armorhead, Pentaceros wheeleri, a deep-sea fish inhabiting the Emperor Seamount Chain caused a serious population decline. Therefore, it is urgently necessary to clarify its genetic diversity and connectivity among populations of P. wheeleri for appropriate stock management. For this, we compared 677 base pairs (bp) of mitochondrial (mt) DNA control region (CR) sequences of 80 individuals from three seamounts (the Milwaukee, Kinmei, and Koko Seamounts) in the southern part of the Emperor Seamount Chain. Contrary to our expectation, the three seamount populations showed high genetic diversity, not yet reflecting effects from the recent population decline or due to mixed two clades. Analysis of molecular variance indicated no significant genetic differentiation between seamount populations, however, the neighbour-joining tree and minimum spanning network showed significant separation into two clades (K2P distance= 1.2–3.2%, ϕ_st = 0.5739, p < .05) regardless of seamount. The divergence time between the two clades was estimated to be 0.3–0.8 Mya, during the period of Pleistocene glacial cycles, suggesting that associated environmental changes and the unique life history traits of Pentaceros spp. might have resulted in the initiation of divergence between these clades.

Keywords:

• Mitochondrial DNA
• control region
• Emperor Seamount Chain
• Pentaceros wheeleri
• population structure

Disclosure statement

The authors report no conflicts of interest. The authors are responsible for the content and writing of this article.

Additional information

Funding

This research was supported by the Marine Fish Resources Bank of Korea under the Ministry of Oceans and Fisheries, Korea [20170431] and the National Institute of Fisheries Science, Korea [R2018025].