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Casting Away the Future of Fishing.
An integral component of recreational fishing tackle are lead sinkers. The two primary uses of lead sinkers are firstly to assist in enhancing the distance of the fishermen cast, and secondly, to anchor the baited hook on the seabeds so that it doesn't drift while waiting for a fish to strike.
Despite the benefits that lead sinkers present to a fishermen, they also present a liability, especially during the recovery of the tackle for rebaiting. The lead sinkers, if the line is not recovered at high speed, drags on the seabed and often snags on rocks, in gullies and on overhangs.
Research by the Strandloper Project has demonstrated that close to 20% of snagged fishing tackle on our Gericke's point survey transect snags on a single rock in the high cast zone across the transect.
Poisoning the Reef
Observations on our survey dive of the reef around sites where there are high accumulations of lead sinkers reveal that marine fauna and flora usually associated on the reef are absent, leaving the reef with a barren dull appearance.
In contrast, sections of reef that are outside of the high cast zones and beyond the range of casting are vibrant and flourishing with both marine fauna and flora which attracts numerous shoals of small bait fish.
Why be concerned about lead sinker accumulation?
The impact of lead poisoning is well documented in humans, particularly in high density urban enviroments.A highly toxic metal in aquatic environments, in nature, lead is considered as a bioaccumulator, accumulating in high levels higher up the food chain In fish lead accumulates in the muscle tissues and lead poisoning causes oxidative stress resulting in synaptic damages and neurotransmitter malfunction. As bioaccumulators, lead poisoning in fish poses a threat to humans that consume it.
On a trophic level, lead also kills reef organisms, effectively destroying the food base of a reef. With the base level of the food chain destroyed, there is the knock on impact of lower biodiversity and the subsequent reduction in marine biomass around areas that have lead sinker accumulation.
Hunting shies away from lead shot
In the hunting industry, research of the impact of lost lead shot on the environment and scavenging species has initiated a drive to replace lead in hunting ammunition. Studies have shown that raptors and covids as well as some mammal species die from lead poisoning caused by unrecovered ammunition in regularly hunted areas.
100 Pieces of Lead
One site is particular, a recessed hole in the coastal shelf contained exactly 100 lead sinkers. At the time of discovering this site, there was no marine flora and fauna growing on the walls of the hole. 11 months after removing all the lead, a follow up survey reveal the onset of both flora and fauna species colonizing the walls of the hole, an indication that the presence of of the lead sinker was detrimental to the marine organisms.
Supporting the evidence that accumulated lead sinkers are detrimental to, recent surveys on our Gericke's Point research transect indicate the recruitment of algal species on sections of formally degraded reef close to high accumulations of lead sinkers. Read More
Lead alternatives.
The popular use of lead for sinkers is due to the specific gravity of lead and the ability to cast uniformly weighted sinkers with ease, providing consistency in different size categories.
In Sedgefield, a local retiree, in an effort to reduce the incidence of lead poisoning caused by lead sinkers, has crafted a range of sinkers made from stones with two weight categories.
In line with the move in the hunting industry, more effort is required by the recreational fishing industry to investigate alternative materials for lead in the manufacture of sinkers as long term means to mitigate the impact of lead poisoning on reef fauna and flora. |
