A sad loss and a straw in a nose

Earlier this week, an 813-pound sea turtle was found dead off the coast of Massachusetts, which likely died from injuries caused by marine fishing gear, despite the use of turtle exclusion devices in many commercial fisheries.  The turtle was a leatherback sea turtle (Dermochelys coriacea), which is both the largest living turtle and a spectacular animal that we have reduced the population of, to the point where it is classified as Vulnerable by the IUCN. There is, however, a definite potential for the decline of this and other turtles if we do not step up to the mark in terms of conservation practices and multi-disciplinary approaches.

Aforementioned turtle :(, Source

The leatherback sea turtle provides a perfect platform to discuss a variety of human impacts on marine ecosystems.  One of the biggest threats is the commercial fishing industry, many turtles are caught as bycatch, approximately 1500 mature females alone in the eastern Pacific in the 1990s. Turtle excluder devices are ineffective with mature adults, as they are actually too big to get through the holes intended for their escape. Their pelagic lifestyle makes them common bycatch for vessels fishing for tuna swordfish and sharks, as the congregate in the same areas of upwelling that the leatherbacks use to feed. The turtles, being marine reptiles and not true fish (But seriously, let's not go there about what type of reptile they are - I had to write a paper on that last year. If you're interested, see a variety of papers with awful, awful names), need to return to the surface to breathe and often drown as a result of being caught up in the nets.

Second on the list is habitat loss. Sea turtles are hugely dependent on beaches for nesting, and although not as often as other turtles, tend to return to their own hatching beach. A variety of typical anthropogenic crimes on the environment: sea level rise, mass tourism and unconstrained coastal development, litter and pollution and others have disturbed and even completely destroyed some crucial turtle nesting beaches around the world. It is unfortunate that many of the areas where the turtles nest (Malaysia, Brazil, Costa Rica, Carrbiean Islands, etc) are all popular tourist destinations for the very beaches the turtles need. The coral reefs as well,  which are important feeding grounds, are suffering extensively as a result of bad tourism practices in many Caribbean countries. Many of the beaches also experience widespread illegal egg take, which seriously hampers leatherback numbers and distorts the natural sex ratio. A recent study  by Ohiana et al. discuss the viability of conservation options in regards to protecting the the nests of leatherbacks in the Dominican Republic. In the Dominican Republic there have been protection measures in place since 1974, but there is still an on going battle to protect the turtles. At one beach, clutch relocation has been in place since 1974 and is still assessed as the only viable option for the area, due to the sheer scale of the illegal poaching. Other beaches have had to implement less drastic measures, such as artificial incubation, but as the paper summises, community engagement and enforcement is needed in order to improve conservation measures. If we want to move towards more sustainable intervention tactics, the locals need to work with the scientists.

The final threat I will mention (but trust me, there are plenty more) is the often fatal impacts of pollution, both chemical and physical. Many turtles die from internal injuries and blockages caused by the ingestion of non-digestable material, such as a plastic bag which the turtle mistook for a jelly fish. Chemical pollution as well, impacts the viability of leatherback eggs, with high levels of the plastic compounds being measured in the yolks of their eggs. 83% of all sea turtles sampled in a recent study had ingested anthropogenic debris, of which plastic was the most prominent component, accounting for 95% of the dry weight of the total ingested material. This study highlighted out lack of understanding about the mechanisms which affect the dispersal of anthropogenic debris around the oceans and how these turtles end up ingesting it. To really ram the point home, and make you feel a bit bad for every McDonalds straw you've ever discarded carelessly, please take a look at the video below - a very real example of what can happen as a result of our carelessness.

EDIT: Here is a link to the GoFundMe page of the PhD Researcher who narrates in the above video, if you're interested in her work, take a look!