Broadbill swordfish (Xiphias gladius) are fished commercially throughout the world and represent a significant component of returns to longline fishing vessels operating in the Australian Fishing Zone (AFZ). Increased pressure on the fishery, rising transport costs and increased international competition for market share, place greater demands to achieve premium quality and prices for this limited resource. BRS statistics state that between 60-70% of swordfish caught in the AFZ are landed dead. This study evaluated the effect of landing swordfish live, and dead, on the ultimate quality of the flesh. Other aspects of onboard swordfish handling were also examined. K-values (ratios of selected nucleotides) and lactate were used as the primary indicators of flesh quality. 226 swordfish were sampled onboard commercial longline fishing vessels, firstly at landing and then directly after transfer from the vessel prior to processing. Liquid nitrogen was used to store samples frozen at sea and on shore. Swordfish landed dead displayed K-values up to four times higher than those landed live and rarely achieved export quality. Three chilling methods used on longline fishing vessels were evaluated: ice slurry, refrigerated seawater (RSW) and refrigerated brine (RB). Temperature loggers placed in the swordfish trunk revealed a lag time of up to 30 minutes in the commencement of core temperature reduction in trunks suspended in ice slurry. These lag times were rarely observed in RSW and RB. Ice slurry also resulted in the greatest change in K-value, being approximately 50% greater than the K-values for RSW and RB. However, swordfish chilled in ice slurry displayed the lowest increases in lactate, another historical measure of fish muscle freshness. This apparent anomaly appears to be a result of lactate being cleared in situ by a small but significant gluconeogenesis process in the white muscle tissue, instigated by the reverse activity of pyruvate kinase; possibly a direct result of swordfish trunks remaining at elevated temperatures (>20°C) for a significant time after death. Storage time was also demonstrated to exhibit a significant influence on swordfish quality. Another factor affecting swordfish quality is the muscle parasite Kudoa musculoliquefaciens. Industry stakeholders estimate up to 5% of the catch from both east and west coast fisheries is lost to the parasite. Two swordfish were identified by histology as being infected with the parasite; however, only one of these exhibited any protease activity as described by Konagaya (1982). Preliminary tests with Near Infra-red Spectroscopy (NIR) were conducted to ascertain its suitability to screen swordfish for Kudoa musculoliquefaciens infection. The NIR beam proved capable of penetrating swordfish tissue to a depth of 30mm from the skin surface. A definitive NIR spectrum for infected swordfish was not obtained due to an insufficient number of infected swordfish.