Turtles and tortoises are central to the food web. Sea turtles graze on the sea grass found on the ocean floor, helping to keep it short and healthy. In turn, healthy sea grass is an important breeding ground for many species of fish, shellfish, and crustaceans. It is the same for freshwater and land turtles as turtles contribute to the health of marshes and wetlands.
However, turtles and tortoise are in serious trouble. Although turtles have been on the planet for about 220 million years, scientists now report that almost half of all turtle species is threatened. Find out more in the sections below.
The International Union for the Conservation of Nature (IUCN), an organization that maintains a comprehensive list (Red List) of the status of the world's species, categorizes 47% of all living turtle species as threatened. Currently, 328 species of turtles are known worldwide, and they are being impacted by a variety of major threats, to which many are gradually succumbing. In overwhelming numbers, turtles are being collected, traded, and eaten or otherwise used. They are used for food, pets, traditional medicine—eggs, juveniles, adults, body parts—all are exploited indiscriminately, with little regard for sustainability. On top of these targeted attacks, their habitats are being increasingly fragmented, destroyed, developed, and polluted. Populations are shrinking nearly everywhere.
Species worldwide are threatened and vulnerable, many are critically endangered, others teeter on the very brink of extinction, and a few have already been lost forever. Eight species and two subspecies having gone extinct since 1500 AD.
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In the United States, there are 7 families of turtles, comprised of 18 genera with 48 species.
Exploitation is the largest problem for turtles and tortoises. They are being collected from the wild, hundreds at a time in most cases. A large percentage of these harvested turtles are shipped overseas to Asian and European markets as pets, as a food source, or for medicinal usage. Many states and countries do have regulations related to harvesting and selling, but not all do.
With the turtle trade, the demand for turtles is much higher than the supply. By law, most turtles less than four inches in length cannot be removed from the wild nor sold in a pet store. This results in “adult” turtles being removed from the wild, which are all the turtles that can reproduce. So in the case of the Box Turtle, an adult female can produce only a couple hundred eggs in their lifetime, and maybe only four out of that one hundred eggs will make it to an adult. For every female Box turtle collected from the wild, there are at least 100 eggs left to add to the wild population.
In addition to the fishing lines mentioned above, other fishing equipment can also cause major problems for turtles. Turtles and other marine life can become entangled in gillnets, pound nets, and the lines associated with longline and trap/pot fishing gear. Entanglement can result in drowning and often serious injuries to the turtle’s flippers from constriction by the lines or ropes. Additionally, entangling turtles, longline gear can also hook turtles in the jaw, esophagus, or flippers.
Trawls, which are nets towed behind a boat to collect organisms, have been used by fishers for centuries. Trawls that are not outfitted with turtle excluder devices (TEDs) do not allow turtles to escape, which may result in mortality through drowning. Likewise, fishing dredges, extremely heavy metal frames drug along the ocean bottom, can crush and entrap turtles, causing death and serious injury.
“Reduce, reuse, and recycle” cannot ever be overstated. Garbage that is left in the wild pollutes our environment, and in many cases, causes wildlife, including turtles harm.
By now, you have probably heard that plastic takes hundreds if not thousands of years to decompose. This may be true, but note that plastic will not stay in its original form whether it is an empty milk container or a six pack of rings. These will start to biodegrade within a year due to harsh outdoor conditions. Plastic can cause serious harm and sometimes death to turtles and other wildlife. Plastic bags may look like jelly fish for some turtles, and if they consume the plastic, the turtle may experience a very slow torturous death as plastic blocks their stomachs, potentially starving them to death. Items like fishing lines and nets can trap practically every kind of animal, including turtles. The result may be infections, suffocating, immobility, starvation, and in a lot of cases, death.
So how does plastic and other garbage make it into the oceans and other waterways? The most direct way is through illegal dumping or accidental loss of equipment such as nets and other items. However, the majority of garbage is making its way into the wild is through storm runoff drains and simply being blown into the water by wind from beaches and piers. People often think that littering just one thing will create problems, but when thousands of tons of little items are washed away from every corner of the world it ends up in one giant garbage pile or rather a giant garbage patch floating in the middle of the ocean degrading into smaller pieces and leeching toxic chemicals like BPA & Styrene Trimer. These toxic chemicals eventually make their way into fish (and all marine life) and make their way up the food chain all the way up to Humans.
Environmental contamination can come from many sources, from runoff, construction, dredging, aquaculture, natural resource exploration and extraction. Fueling facilities can sometimes discharge oil, gas, and sewage into sensitive estuarine and habitats. Likewise, increased under water noise and boat traffic can degrade marine habitats used by turtles. An increase in the number of docks built may also increase boat and vessel traffic. Turtles swimming or feeding at or just beneath the surface of the water are particularly vulnerable to boat and vessel strikes, which can result in serious propeller injuries and death.
Climate change is expected to cause entire ecosystems to change, with a slow poleward migration of species. Researchers are already finding that the slowest-moving species, including turtles, are providing the earliest signals of global warming.
Since turtles are so slow moving, they need to start their migration earlier, providing a ten to twenty year longer lead time in the anticipation of future global temperatures than any other species. It’s already being witnessed that sea turtles are making their nests at higher and higher points on the beach, farther above sea level, in apparent anticipation of future sea level rise from the warming climate. Reports of tropical turtle sightings far from their original habitats continue to pour into turtle research centers around the world.
While migrating, turtles are at an even greater risk as they have to cross roads and highways that they’re not familiar with. They have to do so to survive, even with the risk of being struck by vehicles. A number of states are considering adding turtle crossing signs in areas of frequent turtle sightings, and in some cases, some officials are looking at digging 'turtle tunnels' under road beds in those areas to provide greater safety for the migrating turtles.
We’ll break down some of the other factors below:
Turtle habitat losses result from: urban sprawl, farming, logging, road construction, and predators just to name a few. Looking at Wisconsin, the state has lost over half of its wetlands since European settlement. Urban sprawl, including the construction of new roads, permanently removes habitat used by turtles and other wildlife. Unfortunately, turtles are no match for automobiles, and development around lakes and rivers also affects turtles. As shoreline habitat is developed there are fewer places for female turtles to nest. In order for populations of turtles to survive large areas of habitat that aren't broken up by development and roads must be available.
Another threat to turtles is the increasing number of medium-sized predators that eat turtle eggs, hatchlings, juveniles and adults. These predators include free-roaming cats and dogs, raccoons, skunks, and coyotes. In some areas turtle nest predation rates range from 90-100 percent. That doesn't leave very many young turtle survivors.
Turtles that use the coastlines have their own set of habitat issues to contend with in addition to the general ones mentioned above. For example, the loss or degradation of nesting habitat, resulting from erosion control through beach nourishment and armoring, beachfront development, artificial lighting, and non-native vegetation is a serious threat affecting nesting females and hatchlings. While beach nourishment, or placing sand on beaches, may provide more sand, the quality of that sand and the nesting beach may actually be less suitable than pre-existing natural beaches. Likewise, sub-optimal nesting habitat may cause decreased nesting success, place an increased energy burden on nesting females, result in abnormal nest construction, and reduce the survivorship of eggs and hatchlings.
Beach armoring means the addition of bulkheads, seawalls, soil retaining walls, rock revetments, sandbags, and geotextile tubes. While these can protect a community, unfortunately they can impede a turtle's access to upper regions of the beach’s eco-system, limiting the amount of available nesting habitat. Likewise, impacts can occur if structures are installed during the nesting season. For example, unmarked nests can be crushed or uncovered by heavy equipment, nesting turtles and hatchlings can get caught in construction debris or excavations, and hatchlings can get trapped in holes or crevices of exposed riprap and geotextile tubes. In many areas of the world, sand mining (removal of beach sand for upland construction) seriously degrades and destroys nesting habitat.
If on or near the coast, artificial lighting negatively affects both nesting and hatchling sea turtles. In fact, artificial lighting may deter adult female turtles from emerging from the ocean to nest and it can also disorient emerging hatchlings away from the ocean. Hatchlings have a tendency to orient toward the brightest direction, which on natural, undeveloped beaches is commonly toward the broad open horizon of the sea. However, on developed beaches, the brightest direction is often away from the ocean and toward lighted structures. Hatchlings unable to find the ocean, or delayed in reaching it, are likely to incur high mortality from dehydration, exhaustion, or predation. Hatchlings lured into lighted parking lots or toward streetlights can get crushed by passing vehicles.
Finally, another habitat that coastal turtles have to deal with is non-native vegetation which has invaded many coastal areas and often competes and crowds out native species. Usually, non-native vegetation is less-stabilizing, leading to increased erosion and degradation of suitable nesting habitat. Non-native vegetation may also form impenetrable root mats that can prevent proper nest cavity excavation, invade and desiccate eggs, or trap hatchlings.
Some water turtles can carry Salmonella bacteria. Salmonella does not generally cause illness in the turtle, and generally a person will not contract the illness simply by being around the turtle. That said, severe illness can occur by human handlers, particularly very young people, very old people, and those with compromised immune systems.
Fibropapillomatosis (FP), is a major threat to Green turtles in some areas of the world. FP is characterized by tumorous growths, which can range in size from very small to extremely large, and are found both internally and externally. FP tumors can interfere with feeding and required behaviors, and tumors on the eyes can cause permanent blindness. FP has been recorded in many green turtle populations around the world as well as in populations of Loggerhead, Olive Ridley, and Flatback turtles. The effects of FP at the population level are not well understood.