New lead contamination research and deer management implications.
A study titled “Highlighting the risk of environmental lead contamination for deer management in Australia” was published just before Christmas in 2023. This research aimed to characterise deer carcass contamination via bullet fragmentation associated with lead-based and lead-free ammunition. The study was conducted in 2021 and 2022 using a Hog deer culling program with professional shooters at Wilsons Promontory in Victoria. One of the reasons Hog deer were nominated as ideal candidates for the study was their smaller size, which enabled them to be X-rayed in the field.
Unsurprisingly, the study found that animals shot with lead bullets featured a greater spread of bullet fragments within the hog deer carcass, including in muscles such as the back strap and shoulder, typically utilised for human consumption. The calibre used in this study was a .308 Winchester.
The cause for concern regarding lead is that it is a non-specific toxicant that can negatively affect numerous physiological and biochemical systems, including the nervous, vascular, renal, immune, and reproductive systems. Hence, it’s phasing out of everyday products such as fuel and paint. Lead shot for duck hunting was banned in Victoria in 2002 and even longer in Tasmania and South Australia.
According to the World Health Organisation, humans have no safe level of lead consumption.
There is also the added complication of other species being affected by lead-shot carcasses, such as the Wedge-tailed Eagle, Tasmanian Devil, and Dingoes, to name but a few.
At this point in time, there is no documented evidence of lead having population-level impacts on such species, but it remains front of mind.
As the conversation continues regarding non-lead bullets, animal welfare will remain a key consideration as people begin considering a change in ammunition. In 2022, a study demonstrated some, albeit minimal, differences in animal welfare outcomes on sambar deer using copper bullets. Further research is being conducted on copper bullets and their efficacy on fallow deer. This will help fill the knowledge gap surrounding their efficacy in varied Australian environments. This research is something that members of the ADA are keenly contributing to.
On the back of this study, it gives pause for land managers Australia-wide to reassess their use of lead ammunition in animal (deer) management. Some land managers, such as Parks Victoria, have already mandated using copper projectiles on some programs. And will look at the possibility of expanding this after further investigations. Many hunters have already made the switch, and more will do so regardless of their regulatory environment.