Achievements from the 2013-14 Annual Report

Unsustainable hydroelectricity and irrigation development has decimated global freshwater fisheries, impacted the livelihood of riverine communities and facilitated the decline of fish-based economies. Fish passage devices allow fish to move through, around or over barriers, and offer a potential solution to restore migration. An ACIAR-funded project has investigated the potential impact of water infrastructure on downstream migrating fish within the Lower Mekong Basin, and sought out some solutions to the problem. Initial research focused on upstream movement in Laos and trialled several different fishway designs in a temporary, experimental setting. Having determined the best design, a permanent 120-metre cone fishway was then built at Pak Peung Regulator in Pakxan district, central Laos. This fishway is the country’s first ever designed for Mekong species. Research is now focusing on how well the many species attempting to migrate at the site can pass through.

Pig production is becoming increasingly important for food security in Laos. The vast majority of pigs are produced in the smallholder sector using low-input traditional methods and these farming practices present opportunities for the transmission of a broad range of medically important zoonotic infectious diseases. A project to manage pig-associated zoonoses (diseases that can pass from animals to humans) in the country sought to establish the evidence base regarding the presence of these zoonoses and their socioeconomic impact. The project found that the human and pig populations studied had a very high prevalence of parasitism, and zoonotic transmission between humans and animals was apparent for multiple species of parasitic organisms.

ACIAR’s teak research in Laos, led by the University of Queensland, has studied the growth of teak at different initial stocking densities through the use of ‘Nelder Wheel’ trials. In these trials, teak is planted in rows along the ‘spokes’ of a wheel shape in the field. Because the distance between rows increases as you move out from the centre of the trial, you end up with different planting densities at each point along the spoke. Monitoring these trials over 5–10 years enables researchers to determine the average growth of the teak at different stockings (from 100 to 2,500 trees per hectare). Five years down the track, this research is showing that the best rate to plant to maximise tree width and height is 600 trees per hectare. This is a fraction (a third or less) of the number of trees traditionally grown per hectare. Importantly, this approach gives farmers the option of growing crops in the extra space between trees.