Two subspecies of Haliporoides triarthrus are presently recognized from the SWIO region, H. triarthrus triarthrus from South Africa and Mozambique, and H. triarthrus vniroi from Madagascar and Mozambique. Haliporoides triarthrus occurs on the continental slope at depths of 300 to 800 m, but is more commonly fished between 400 and 600 m.Haliporoides triarthrus make up most of the deep-water trawl catches in Mozambique and South Africa, and are endemic to the SWIO region (Zacarias 2013).

Zacarias (2013) found distinct meta-populations of knife shrimp H. triarthrus along the South West Indian Ocean area but considered that further research should be conducted at others levels (site and region) and using other techniques to verify the stock structure and also properly identify stock boundaries for fisheries management purposes. The map below regards the distribution of the species along the Mozambican coast. 

Between 1990 and 2010, the majority (91%) of catches of H. triarthrus originated from Mozambique (26 153t) and South Africa contributed 9% (2 576t) to reported catches (Groeneveld 2012). Despite the economic importance of H. triarthrus to deep-water trawl fisheries in the SWIO region, little is known about its biology and population dynamics.