The global biology, ecology and phylogenetic status of black marlin (Istiompax indica)

Abstract

The black marlin [Istiompax indica (Morrow, 1968)] is one of the largest teleost fish and has a continuous distribution throughout tropical waters of the Indo-Pacific. Throughout its range, I. indica has been documented to undertake wide-ranging, transoceanic and transequatorial movements. In coastal waters and on the high seas I. indica may be targeted by commercial and artisanal fisheries, but the majority of the world's landings are as a by-product species of tuna longline and purse seine fisheries. Due to its large size and 'fighting qualities', I. indica is also valued as a prized sport or game fish in recreational fisheries. While considerable effort to understand the level of exploitation of high value species such as the tunas has occurred, the stock status for many other species caught on the high seas such as many sharks, dolphinfish and istiophorid billfishes remain unassessed. This lack of attention is reflected by I. indica being listed as 'Data Deficient' on the International Union for Conservation of Nature Red List. The lack of attention and data available on I. indica extends to biological, ecological, taxonomic and fisheries catch records, which in turn hinders stock assessments and management. This thesis aims to improve the biological and ecological knowledge of I. indica, thereby providing a stronger foundation for assessments and management of stocks globally. PUBLICATIONS DURING CANDIDATURE Peer-reviewed papers and book chaptersA Cohen, D. Spooner and SM. Williams (In Press). Examining the importance of marine transport and transport infrastructure and the initiatives adopted for managing potential impacts whilst enhancing transport services. Moreton Bay and Catchment.

Genome‐wide SNPs resolve spatiotemporal patterns of connectivity within striped marlin (Kajikia audax), a broadly distributed and highly migratory pelagic species

“…Incomplete biological information for samples comprising NPO2 prohibits comparisons Regional movements of striped marlin generally correspond with the genetically distinct populations described here (Domeier, 2006;Holdsworth et al, 2009;Ortiz et al, 2003;Sippel et al, 2007). The and a third population in the South China Sea (Williams, 2018).…”

“…Assessment of over 6,000 SNPs for yellowfin tuna in the Pacific Ocean resolved genetically distinct populations in the western South Pacific, central Pacific, and eastern North Pacific oceans (Grewe et al, ), demonstrating regional population structure similar to that observed in the present study. In contrast, analyses of over 1,500 SNPs in black marlin ( Istiompax indica ) identified a single population spanning eastern and western regions of the Indian Ocean; a second population spanning the western South Pacific, central North Pacific, and eastern central Pacific oceans; and a third population in the South China Sea (Williams, ). Identifying mechanisms underlying differences in ocean‐wide patterns of genetic connectivity among large pelagic fishes requires improved knowledge of species' biological characteristics (e.g., thermal preferences, dispersal capabilities, degree of fidelity to natal spawning grounds) and sensitivity to obvious or cryptic barriers to movement.…”