How reliable are turtles for measuring ocean trash and marine health?

Some suggestions for improving the science of turtle research.

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Marine debris, including plastics, paper, wood, metal, and other manufactured materials are found on beaches worldwide and at all depths of the ocean. About 60%-80% of all marine debris is composed of plastic (Rios et al. 2007) and Ocean Conservancy’s Trash Free Seas Alliance estimates that 8 million metric tons of plastic enter the ocean each year.

Scientists and the public, in general, are concerned about the increase in ocean trash and the effects of plastics on marine life. Various scientific reports assume that turtles resemble canaries in coal mines with regards to monitoring the strength of the ocean and marine life.

In any case, another examination distinguishes a vital imperfection in these suspicions. The examination also provides some suggestions for improving the science of turtle research. Her hope is to make ocean garbage data a bit less likely to be trashed.

The certainties apparently point to turtles as being basic markers of the ocean and marine health. Turtles live long lives and possess distinctive regions of the globe. Distinctive species feed at various depths of the water, as well.

Past scientific examinations have likewise established that numerous turtles frequently get a kick out of the chance to eat things that are not food, including plastic bits. Half of all the sea turtles living today have likely ingested such garbage, as per past investigations. A few turtle animal varieties are recorded as endangered.

Jennifer Lynch of the National Institute of Standards and Technology (NIST) said, “Turtle work over the last 50 years has often only focused on the presence or absence of debris while neglecting to note the amount of garbage found in each turtle gut. Also missing from many past studies: The weight and size of the turtles in question. And very little has been done to compare trash-ingestion data across species.”

“This, unfortunately, makes many of these past turtle studies worthless to those wanting to know where ocean debris is occurring in large amounts and what species are the most in need of conservation. It can be frustrating.”

“Trash in turtles should really be handled no differently than any other kind of toxicological issue. When doctors determine the risks of environmental toxins on a patient, they base their conclusions on the amount of the substance in question and the patient’s attributes such as weight, age, and size.”

“It is hard for some people to imagine plastic as a toxic substance, although for turtles, it very well could be.”

“But right now, we don’t know the thresholds. We don’t know at what point plastic causes physiological, anatomical or toxicological impacts on these creatures.”

“Studies shouldn’t just report that trash was found in the gut. Studies should indicate the species because the different kinds of sea turtles travel in different parts of the oceans. Studies should also show how much trash was discovered in the turtles’ digestive systems, and physiological details like whether the animal was a small hatchling or a large adult.”

“Grams of trash per kilogram of turtle (g/kg) is the metric scientists should be using. That kind of standardization in reporting would reveal how much trash the turtles are encountering, and which species is being most affected by trash. It also could enable analyses on toxicity.”

“Much of the data on the topic of turtles and trash is based on autopsies of what were sick or injured animals, which can perhaps throw off data when trying to determine the role of trash in their deaths. We need to develop noninvasive ways of getting turtle-trash data from healthy individuals.”

To reach her decisions, Lynch examined scientific reports on garbage taken from the stomachs of different ocean turtles dating the distance back to 1970. Altogether, 131 investigations were looked into. Of those, 39 did not give the sort of information required for examinations since they just portrayed the presence of debris and not the amount. Also, 41 of the examinations did not give the span of the turtle being considered.

One brilliant note in the meta-investigation originated from species reporting. There was sufficient information on that metric during that time for her to have the capacity to see that two species are the most in danger for ingestion, given the number of times they have turned up in either rescues or recuperation after-death events with generally a lot of waste in their stomachs. They are hawksbills (Eretmochelys imbricata), a critically endangered species in the Atlantic Ocean that can weigh 150 pounds), and green turtles (Chelonia mydas), an imperiled species found in both the Atlantic and Pacific that can weigh as much as 350 pounds.

Once the current group of research had been changed in accordance with address the issue of relative turtle weight, it likewise turned out to be certain that preservation endeavors were not being coordinated towards the geographic areas that were problem areas for hot spots and debris.

Lynch said, “Monitoring for this problem has been disproportionate in the past, with too small a focus placed on the wrong areas. A lot of the focus has been on the Mediterranean, but I found that the turtles in the Central and Northwest Pacific and Southwest Atlantic have a much higher rate of ingestion of plastic.”

“It is important to acknowledge garbage pieces, especially plastic bits, are unnatural and don’t belong in the ocean, Lynch noted. Exposure to chemicals in the garbage is concerning to scientists because it remains unclear how many of the chemicals found in the plastic trash are moving through the food chain and how they affect the health of both wildlife and humans who eat fish or live near the coast. Finding ways to gather more information on the topic is important to many who want to find effective solutions. Turtles also play a large role in the function of the ocean ecosystem, and several species are listed as endangered, so their conservation is of special concern.”

“But the problem may be easier to measure than other exposure issues, provided that the right data is gathered in future studies. Turtles could eventually provide important clues to where garbage is worst.”

“Plastic litter is one of the few contaminants that can be seen with the naked eye. The work can be painstaking, and sometimes kind of gross. But it only requires simple lab tools and methods and does not really demand expensive chemical instrumentation. If we improve our methodologies and data collection points and standardize our reporting and analysis, we will likely gain more useful info out of the process for managing our oceans and our garbage.”

The study is published in the journal Environmental Science and Technology.