Humans harm great white sharks in several significant ways, from direct killing through fishing and beach safety programs to slower, less visible threats like pollution and habitat disruption. The species is classified as Vulnerable globally on the IUCN Red List, and Critically Endangered in the Mediterranean and European waters. What makes these threats especially dangerous is that great white sharks reproduce so slowly that populations struggle to bounce back from even modest losses.
Beach Safety Programs Kill the Most Directly
One of the most measurable sources of great white shark deaths comes from government-run beach protection programs. In Australia, shark nets and baited drum lines are deployed along popular swimming beaches in New South Wales and Queensland. Over a ten-year period from 1993 to 2003, these programs captured 143 great white sharks. Of those, 138 died or were killed after capture, averaging nearly 14 deaths per year in just two Australian states. These aren’t targeted hunts. The sharks swim into mesh nets set near shore or bite hooks on drum lines designed to reduce the risk of shark encounters with swimmers. The nets don’t form a complete barrier; they work by reducing the local shark population, which means killing is the mechanism, not exclusion.
South Africa runs similar programs along the KwaZulu-Natal coast. Because great whites are apex predators that patrol coastal waters where people swim, they’re among the species most frequently caught. These programs put conservation agencies in a difficult position: the sharks are legally protected in both countries, yet beach safety infrastructure continues to kill them.
Fishing Pressure and Bycatch
Great white sharks are protected from targeted commercial fishing in most countries, but they still die as bycatch when caught in gear meant for tuna, swordfish, and other species. The scale varies by region. In Hawaii’s longline fishery, for example, observer records spanning three decades and roughly 250 million hooks logged only 8 white shark captures, making bycatch there negligible. But Hawaii sits at the edge of the white shark’s range. In waters where the species is more common, particularly off the coasts of Australia, South Africa, California, and the Mediterranean, interactions with commercial and recreational fishing gear are more frequent.
Gillnets pose a particular risk. Unlike longlines, which a shark might survive if released quickly, gillnets can entangle sharks for hours, often drowning them before fishers return to check the gear. Great whites need to keep swimming to push water over their gills, so any net entanglement that restricts movement can be fatal.
The Illegal Fin Trade
Although great white sharks aren’t the primary target of the global shark fin trade, the broader illegal market creates a hostile environment for all large shark species. A major study analyzing nearly 20,000 shark fin samples from Hong Kong markets between 2014 and 2021 found that fins from species protected under CITES (the international treaty regulating trade in endangered wildlife) remained widely available years after trade restrictions took effect. Hammerhead and oceanic whitetip fins were found at levels 10 to 70 times higher than legal trade records would predict. Roughly 81% of shark-fin-exporting countries have never reported any trade in these protected species, a strong indicator that illegal exports are widespread.
Great white sharks have their own CITES protections (Appendix II), which means international trade requires permits and proof of sustainability. But the same enforcement gaps that allow hammerhead and whitetip fins to flood markets also leave great whites vulnerable. DNA testing has traced protected shark fins sold in Hong Kong to six ocean regions, some of which had no legal export records at all. Countries flagged for likely involvement in the illegal trade include Spain, Taiwan, the United Arab Emirates, China, the Philippines, Ghana, and Brazil.
Chemical Pollution Builds Up in Their Bodies
As apex predators, great white sharks sit at the top of the marine food chain, which means pollutants accumulate in their tissues at far higher concentrations than in the fish they eat. A study of white sharks in the Northwest Atlantic found mercury levels in muscle tissue averaging 10.0 milligrams per kilogram (dry weight), with concentrations rising in proportion to the shark’s body size. Larger, older sharks carried more mercury simply because they’d had more years of eating contaminated prey.
Interestingly, that same study found no clear evidence that the mercury was actively harming the sharks’ blood chemistry or health markers. Some individuals had enough selenium, a mineral that can counteract mercury’s toxic effects, to offer protection. Others did not. The long-term consequences remain unclear, but the sheer volume of mercury these animals carry reflects the scale of ocean pollution.
Beyond heavy metals, sharks are also ingesting microplastics. A study of shark species in the North-East Atlantic found that 67% of individuals examined had at least one synthetic contaminant particle in their digestive tract. The overwhelming majority of these were tiny synthetic fibers, likely from clothing and textiles that wash into the ocean. Some of these fibers contain chemicals like BPA that can disrupt reproductive and hormonal systems in marine animals, even at low doses. While this particular study focused on smaller bottom-dwelling sharks, great whites face the same exposure through the food web, eating fish and marine mammals that have already ingested these contaminants.
Ocean Warming Is Reshaping Their Habitat
Rising ocean temperatures are altering where great white sharks can live and hunt. According to NOAA, warming waters are shifting the geographic ranges of predatory species like sharks as their prey moves to track suitable temperatures. For great whites, which depend on seals, sea lions, and large fish, this means their hunting grounds may no longer overlap reliably with their prey. If seal colonies shift northward or into deeper waters, sharks must follow or go hungry.
Warming also affects the broader ecosystem these sharks depend on. Changes in ocean temperature influence plankton blooms, which ripple up the food chain to affect fish populations, which in turn affect the marine mammals great whites eat. These shifts don’t kill sharks immediately, but they increase energy expenditure and reduce feeding success over time, weakening individual animals and making populations more fragile.
Cage Diving and Tourism
Shark cage diving has become a popular ecotourism industry in South Africa, Australia, and Mexico. Operators use chum (a slurry of fish blood and oil) and bait to attract great whites close to boats, giving tourists a close-up encounter. Concerns have centered on whether this conditions sharks to associate boats and humans with food, potentially increasing risky encounters.
Research published in Scientific Reports found that while fresh bait did provoke more aggressive interactions in the short term, the overall evidence suggested current ecotourism practices were not significantly conditioning white sharks over time. All bait types were similarly effective at attracting sharks, but the animals didn’t show signs of becoming dependent on the food source. That said, the study noted potential effects on habitat use, surface behavior, and energy budgets. Sharks that repeatedly visit dive boats may be spending time and energy at tourism sites instead of hunting naturally, a cost that’s difficult to measure but could matter for individual fitness.
Why Recovery Is So Slow
What makes all of these threats especially serious is the biology of the species itself. Great white sharks are one of the slowest-reproducing fish in the ocean. Males don’t reach sexual maturity until around age 9 or 10, when they’ve grown to about 3.5 to 4 meters long. Females take even longer, maturing between ages 12 and 18 at lengths of 4.5 to 5 meters. Gestation lasts roughly 12 to 14 months, and litter sizes are small compared to most fish.
A newborn great white is about 1.2 meters long and grows only around 25 centimeters per year. This means a single female might not produce her first pup until she’s a teenager, and she’ll produce relatively few offspring over her lifetime. When a population loses adults to nets, fishing, or pollution faster than young sharks can replace them, recovery takes decades. This reproductive math is why even modest, sustained human-caused mortality can push a population toward collapse.