Whales and dolphins found in the Great Pacific Garbage Patch for the first time



Adult and infant sperm whales have been spotted in the Great Pacific Garbage Patch.
Inf-Lite Teacher/Flickr, CC BY-SA

Chandra Salgado Kent, Edith Cowan University

Scientific research doesn’t usually mean being strapped in a harness by the open paratroop doors of a Vietnam-war-era Hercules plane. But that’s the situation I found myself in several years ago, the result of which has just been published in the journal Marine Biodiversity.

As part of the Ocean Cleanup’s Aerial Expedition, I was coordinating a visual survey team assessing the largest accumulation of ocean plastic in the world: the Great Pacific Garbage Patch.




Read more:
The ocean’s plastic problem is closer to home than scientists first thought


When the aircraft’s doors opened in front of me over the Pacific Ocean for the first time, my heart jumped into my throat. Not because I was looking 400m straight down to the wild sea below as it passed at 260km per hour, but because of what I saw.

This was one of the most remote regions of the Pacific Ocean, and the amount of floating plastic nets, ropes, containers and who-knows-what below was mind-boggling.

However, it wasn’t just debris down there. For the first time, we found proof of whales and dolphins in the Great Pacific Garbage Patch, which means it’s highly likely they are eating or getting tangled in the huge amount of plastic in the area.

The Great Pacific Garbage Patch

The Great Pacific Garbage Patch is said to be the largest accumulation of ocean plastic in the world. It is located between Hawaii and California, where huge ocean currents meet to form the North Pacific subtropical gyre. An estimated 80,000 tonnes of plastic are floating in the Great Pacific Garbage Patch.




Read more:
The major source of ocean plastic pollution you’ve probably never heard of


Our overall project was overseen and led by The Ocean Cleanup’s founder Boyan Slat and then-chief scientist Julia Reisser. We conducted two visual survey flights, each taking an entire day to travel from San Francisco’s Moffett Airfield, survey for around two hours, and travel home. Along with our visual observations, the aircraft was fitted with a range of sensors, including a short-wave infrared imager, a Lidar system (which uses the pulse from lasers to map objects on land or at sea), and a high-resolution camera.

Both visual and technical surveys found whales and dolphins, including sperm and beaked whales and their young calves. This is the first direct evidence of whales and dolphins in the heart of the Great Pacific Garbage Patch.

Mating green turtles in a sea of plastics.
photo by Chandra P. Salgado Kent, Author provided

Plastics in the ocean are a growing problem for marine life. Many species can mistake plastics for food, consume them accidentally along with their prey or simply eat fish that have themselves eaten plastic.

Both beaked and sperm whales have been recently found with heavy plastic loads in their stomachs. In the Philippines, a dying beaked whale was found with 40kg of plastic in its stomach, and in Indonesia, a dead sperm whale washed ashore with 115 drinking cups, 25 plastic bags, plastic bottles, two flip-flops, and more than 1,000 pieces of string in its stomach.

The danger of ghost nets

The most common debris we were able to identify by eye was discarded or lost fishing nets, often called “ghost nets”. Ghost nets can drift in the ocean for years, trapping animals and causing injuries, starvation and death.

Crew sorts plastic debris collected from the Great Pacific Garbage Patch on a voyage in July 2019.
EPA/THE OCEAN CLEANUP

Whales and dolphins are often found snared in debris. Earlier this year, a young sperm whale almost died after spending three years tangled in a rope from a fishing net.

During our observation we saw young calves with their mothers. Calves are especially vulnerable to becoming trapped. With the wide range of ocean plastics in the garbage patch, it is highly likely animals in the area ingest and become tangled in it.

It’s believed the amount of plastics in the ocean could triple over the next decade. It is clear the problem of plastic pollution has no political or geographic boundaries.




Read more:
There are some single-use plastics we truly need. The rest we can live without


While plastics enter the sea from populated areas, global currents transport them across oceans. Plastics can kill animals, promote disease, and harm the environment, our food sources and people.

The most devastating effects fall on communities in poverty. New research shows the Great Pacific Garbage Patch is rapidly growing, posing a greater threat to wildlife. It reinforces the global movement to reduce, recycle and remove plastics from the environment.

But to really tackle this problem we need creative solutions at every level of society, from communities to industries to governments and international organisations.

To take one possibility, what if we invested in fast-growing, sustainably cultivated bamboo to replace millions of single-use plastics? It could be produced by the very countries most affected by this crisis: poorer and developing nations.




Read more:
Designing new ways to make use of ocean plastic


It is only one of many opportunities to dramatically reduce plastic waste, improve the health of our environments and people, and to help communities most susceptible to plastic pollution.The Conversation

Chandra Salgado Kent, Associate Professor, School of Science, Edith Cowan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The Blinky Bill effect: when gum trees are cut down, where do the koalas go?


Kita Ashman, Deakin University

In the past two decades there has been an unprecedented increase in the area of blue gum (Eucalyptus globulus) plantations in southern Australia. In southwest Victoria alone, some additional 80,000 hectares of commercial blue gum have been planted.

This expansion has significantly increased the habitat available for koalas. In fact, my research, published in the journal Landscape and Urban Planning, has found there are more koalas in plantations than in surrounding native habitat.




Read more:
A report claims koalas are ‘functionally extinct’ – but what does that mean?


More koalas may seem like a good thing, but perversely this could ultimately harm their welfare (and the welfare of other native animals and plants), and disrupt the plantation industry.

Blinky Bill had to leave his home after the trees were bulldozed.

Plantations

Koalas are protected in Victoria, so when plantation managers harvest the mature trees they must have a permit and a koala management plan. These plans focus on locating koalas, ensuring that the trees koalas are sitting in at harvest are not felled, and post-harvest surveys to find any injured koalas.

However, these plans don’t consider where the koalas go after the plantation has been cut down, and what effects their movement has on the landscape and surrounding native vegetation.

A recently harvested blue gum plantation showing remnant trees left due to koalas.
Author provided

To work out how factors such as plantation cover affect koala populations, my colleagues and I surveyed 72 sites across southwest Victoria. We found more koalas in plantations than in blocks of native vegetation or in native roadside vegetation.

We then spatially modelled koala numbers for the region, and found several high-priority areas for population management, as well as significant conservation habitat for koalas and other wildlife in the region that overlap with high koala population densities.




Read more:
What does a koala’s nose know? A bit about food, and a lot about making friends


Our mapping predicted high koala numbers in the southeast, where there are important remnant bushland areas such as Kurtonitj Indigenous Protected Area and Mount Napier State Park. This highlights the importance of considering the overall landscape when establishing and harvesting plantations, and the arrangement of plantations near remnant forest.

Harvest rates in much of southwest Victoria are set to increase. This may result in increased koala numbers in the native vegetation surrounding harvested sites, which could then put pressure on food trees in remnant forests.

Local landholders are already seeing the effect of more koalas on native vegetation. Many trees on private land or beside roads are being stripped of leaves.

Canopy defoliation of remnant trees due to increased numbers of koalas in south-west Victoria.
Author provided

More koalas are also likely to mean more injuries or other welfare issues. As plantations have a responsibility to avoid these, koala injuries could threaten the future of one of the main industries in this region. More than 4,000 people are directly employed in the regional forestry industry, with a further 4,500 in associated service industries.




Read more:
Koala-detecting dogs sniff out flaws in Australia’s threatened species protection


The bigger picture

To meet this challenge, we argue management plans need to consider the larger landscape. What native forest is near a plantation? Where are the koalas likely to go after the harvest? How might they affect other native species?

A female koala being released in Bessiebelle, south-west Victoria, after undergoing a health check.
Esther Wong, Author provided

Such plans could include some areas of plantations set aside for koala habitat, harvesting plans that consider adjacent habitat that koalas may move into, or increasing areas of native food trees. These would all benefit other wildlife in the area, as well as koalas.

Currently, there is something of a negative feedback loop in southwest Victoria. When plantations are established koalas move in and reproduce. When plantations are later harvested, the koalas move into surrounding areas. As a result, populations can rapidly increase in some areas, affecting native trees and creating welfare issues for the forest industry.




Read more:
Victorian koalas are eating themselves out of house and home


We have seen the devastating effects high density koala populations can have on native forests in places like Cape Otway, which saw mass starvation and widespread forest death in 2013 and 2014. Current state regulations could disrupt the forestry industry, especially with koala numbers increasing in plantations but with no plan to really manage koala numbers in southwest Victoria in sight.The Conversation

Kita Ashman, PhD candidate in koala conservation, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.