Plastic Found in 4 out of 10 Seabird Nests

Four out of ten nests surveyed on the uninhabited Lady Isle in the Firth of Clyde, Scotland contain plastic, a study recently published in the Marine Pollution Bulletin has found. The survey, led by a team from the University of Glasgow, was carried out in May 2018. The researchers examined 1,597 seabird nests on the island and found that a whopping 625 contained plastic.

The amount of nests recorded with plastic debris varied between different seabird species. Shags (Phalacrocorax aristotelis) were the worst off, with 80% of nests containing plastic. Meanwhile, 53.5% of great black-backed gull (Larus marinus) nests, 35.6% of herring gull (Larus argentatus) nests, 25% of lesser black-gulled gull (Larus fuscus) nests, and 24.8% of cormorant (Phalacrocorax carbo) nests were found to contain plastic debris.

It is thought that these differences are likely due to the different nest-building behaviours that each species exhibits. For example, shags will reuse the same nest each year, which could allow plastic to accumulate in that nest exponentially.

Most of the plastic found in the seabird nests were identified as consumer waste discarded in urban areas. This was likely then washed to the island and collected by the birds. Dr Ruedi Nagar, a seabird ecologist at the University of Glasgow, explained further:

"They end up in seabird nests, not because seabirds actively pick them up in built-up areas and carry them to their nest, but because they are brought their passively by marine currents."

The research team's data showed that nests on the north side of the Lady Isle, the side closest to the outgoing tide from the mainland, were more likely to contain plastic debris. This, again, suggests that the plastic originated from the mainland and washed ashore, where the birds were then able to collect it from their nesting area.

Nesting herring gull

Danni Thompson, a researcher volunteering with Dr Nagar, focused more closely on herring gulls during the study. As the most abundant seabird species nesting on the island, it was thought that these results, in particular, could provide useful insights on how plastic debris is acquired by seabirds.

She explained, "As herring gulls often forage in landfills, we wanted to see if they were swallowing plastic whilst eating and then bringing it back to the nest." However, the team were able to confirm that the plastic debris most likely arrived by other means, not by ingestion.

While it is useful to have a clearer idea of how plastic makes it way into seabird nests, the next step is to find out the impact it could have, since plastic may negatively affect the eggs and chicks, and also increases the risk of entanglement. Further research is needed to identify the likelihood and extent of these impacts and how they affect seabird populations in the long-term. However, by identifying the source of the plastic debris, the team's findings will help conservationists plan appropriate action to combat this issue in the future.

Highest Number of Leatherback Sea Turtle Hatchlings in 20 Years Recorded on Thai Beaches

Conservationists in Thailand have found the largest number of leatherback sea turtles (Dermochelys coriacea) nesting on their beaches in two decades, Reuters has reported.

Leatherback sea turtles are the largest of the seven sea turtle species, reaching up to 2.4 m in length and 900 kg in weight. They are currently endangered in Thailand and are listed as Vulnerable worldwide on the IUCN Redlist. Like other turtle species, they must come ashore to lay their eggs and will usually do so in dark, quiet areas where they are less likely to be disturbed by humans. As a result, tourism can have a negative impact on the turtles' ability to reproduce.

But beaches in Thailand are now free of tourists due to the current COVID-19 pandemic. As of writing, Thailand has had 2,989 confirmed positive cases and 55 deaths, resulting in a ban on international flights and citizens being encouraged to stay at home. While incredibly unfortunate, this has allowed leatherback sea turtles to nest in areas they would normally avoid, particularly due to the absence of tourists.

Leatherback sea turtle nesting in the sand

Authorities have found 11 nests on Thai beaches since November. This may not sound like much but it is the highest number recorded since the early 2000s. And it gets better. In late March, staff at a national park in Phang-Nga, a province in southern Thailand which borders the Andaman Sea, recorded 84 leatherback sea turtle hatchlings after monitoring eggs for two months.

Kongkiat Kittiwatanawong, the director of the Phuket Marine Biological Centre, explained why this new development is so important:

"This is a very good sign for us because many areas for spawning have been destroyed by humans. If we compare to the year before, we didn't have this many spawn, because turtles have a high risk of getting killed by fishing gear and humans disturbing the beach."

For the last five years, there had been no nests found at all on Thai beaches, so this year's numbers are a significant improvement. While the circumstances that brought about this change are truly awful, it has certainly highlighted the impact that human activity can have on the wildlife around us.

LED Lights on Fishing Nets Help Reduce Bycatch

A simple technique to illuminate the exits in trawling nets could cut accidental bycatch by half a recent study has shown. The study, published in the Journal of the Marine Biological Association of the United Kingdom, found that attaching LED lights to the larger holes in a net allows non-target species to escape, reducing the number that are killed. The research was conducted by a team from Bangor University, led by marine ecologist, Dr Lucy Southworth.

Bycatch, the capture of non-target species, can significantly damage the populations of these species, many of which are vulnerable or endangered, and drastically reduce their numbers. Similarly, seabirds and marine mammals can become victims of accidental bycatch through entanglement in fishing nets, which often kills them in the process.

But it's not just the environment that is negatively affected by bycatch. There is also a significant cost to the fishermen. Under EU law, fishermen are required to bring almost everything they catch to shore, including that which is not a part of their quota. If too many non-target fish are caught, the entire fishery may be closed to allow stocks to recover. As a result, even fishermen doing their best to comply with the rules can cause unintended damage and end up risking their livelihoods.

Trawler at sea

The new study, conducted between June and August 2017, is a clever inversion of an old fishing technique: shining a light on the water to attract fish into the net. The team set out to test the effect of lights in reducing the number of haddock and flatfish that were accidentally caught in a queen scallop fishery off the Isle of Man.

They found that, while the devices that are currently used to reduce bycatch were effective in shallower waters of around 29 to 40 m, they had little to no effect in deeper waters of around 45 to 95 m. This is likely due to the lack of light and, therefore, visibility. Once LED lights were attached to the net exits in these deeper waters, haddock bycatch was reduced by 47% and flatfish bycatch by 25%.

The team even found of evidence of sharks escaping the lit nets, which could be a topic for future research. LED lights could also potentially reduce the number of whales, dolphins, and porpoises entangled in nets each year as they alert the animals to the presence of these nets and give them the chance to avoid the hazard.

Dr Southworth and her colleagues believe that this could be a popular solution to the current issues with bycatch. Not only are LED lights fairly cheap, they are easy to apply to the nets and can be easily adjusted for different environments. Though there is still a long way to go before the issue of bycatch is solved, it's certainly refreshing when simple answers can be found for complicated problems.