Tens of thousands of tuna-attracting devices are drifting around the Pacific



Fish are attracted to floating objects, especially with dangling ropes or nets.
WorldFish/Flickr, CC BY-NC-SA

Joe Scutt Phillips, Secretariat of the Pacific Community; Alex Sen Gupta, UNSW; Graham Pilling, Secretariat of the Pacific Community, and Lauriane Escalle, Secretariat of the Pacific Community

Tropical tuna are one of the few wild animals we still hunt in large numbers, but finding them in the vast Pacific ocean can be tremendously difficult. However, fishers have long known that tuna are attracted to, and will aggregate around, floating objects such as logs.

In the past, people used bamboo rafts to attract tuna, fishing them while they were gathered underneath. Today, the modern equivalent – called fish aggregating devices, or FADs – usually contain high-tech equipment that tell fishers where they are and how many fish have accumulated nearby.




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It’s estimated that between 30,000 and 65,000 man-made FADs are deployed annually and drift through the Western and Central Pacific Ocean to be fished on by industrial fishers. Pacific island countries are reporting a growing number of FADs washing up on their beaches, damaging coral reefs and potentially altering the distribution of tuna.

Our research in two papers, one of which was published today in Scientific Reports, looks for the first time at where ocean currents take these FADs and where they wash up on coastlines in the Pacific.

A yellowfin tuna caught by purse seine fishers. This individual is one of the largest that can be caught using FADs.
Lauriane Escalle

Attracting fish and funds

We do not fully understand why some fish and other marine creatures aggregate around floating objects, but they are a source of attraction for many species. FADs are commonly made of a raft with 30-80m of old ropes or nets hanging below. Modern FADs are attached to high-tech buoys with solar-powered electronics.

The buoys record a FAD’s position as it drifts slowly across the Pacific, scanning the water below to measure tuna numbers with echo-sounders and transmitting this valuable information to fishing vessels by satellite.

Tuna hauled aboard the fishing vessel Dolores. The tuna trade in the Pacific Ocean is worth more than US$6 billion a year.
Siosifa Fukofuka (SPC), Author provided

Throughout their lifetimes FADs may be exchanged between vessels, recovered and redeployed, or fished and simply left to drift with their buoy to further aggregate tuna. Fishers may then abandon them and remotely deactivate the buoys’ satellite transmission when the FAD leaves the fishing area.

The Western and Pacific Ocean provides around 55% of the worlds’ 5 million tonne catch of tropical tuna, and is the main source of skipjack, yellowfin and bigeye tuna worth some US$6 billion annually.

Pacific Islanders with a FAD buoy that washed up on their reef.
Joe Scutt Phillips, Author provided

Fishing licence fees can provide up to 98% of government revenue for some Pacific Island countries and territories. These countries balance the need to sustainably manage and harvest one of the only renewable resources they have, while often having a limited capacity to fish at an industrial scale themselves.

FADs help stabilise catch rates and make fishing fleets more profitable, which in turn generate revenue for these nations.

However, they are not without problems. Catches around FADs tend to include more bycatch species, such as sharks and turtles, as well as smaller immature tuna.

The abandonment or loss of FADs adds to the growing mass of marine debris floating in the ocean, and they increasingly damage coral as they are dragged and get caught on reefs.

Perhaps most importantly, we don’t know how the distribution of FADs affects fishing effort in the region. Given that each fleet and fishing company has their own strategy for using FADs, understanding how the total number of FADs drifting in one area increases the catch of tuna is crucial for sustainably managing these valuable species.

Where do FADs end up?

Our research, published in Environmental Research Communications and Scientific Reports, used a regional FAD tracking program and fishing data submitted by Pacific countries, in combination with numerical ocean models and simulations of virtual FADs, to work out how FADs travel on ocean currents during and after their use.

In general, FADs are first deployed by fishers in the eastern and central Pacific. They then drift west with the prevailing currents into the core industrial tropical tuna fishing zones along the equator.

We found equatorial countries such as Kiribati have a high number of FADs moving through their waters, with a significant amount washing up on their shores. Our research showed these high numbers are primarily due to the locations in which FADs are deployed by fishing companies.

In contrast, Tuvalu, which is situated on the edge of the equatorial current divergence zone, also sees a high density of FADs and beaching. But this appears to be an area that generally aggregates FADs regardless of where they are deployed.

Unsurprisingly, many FADs end up beaching in countries at the western edge of the core fishing grounds, having drifted from different areas of the Pacific as far away as Ecuador. This concentration in the west means reefs along the edge of the Solomon Islands and Papua New Guinea are particularly vulnerable, with currents apparently forcing FADs towards these coasts more than other countries in the region.

FAD found beached in Touho (New Caledonia) in 2019.
A. Durbano, Association Hô-üt’, Author provided

Overall, our studies estimate that between 1,500 and 2,200 FADs drifting through the Western and Central Pacific Ocean wash up on beaches each year. This is likely to be an underestimate, as the tracking devices on many FADs are remotely deactivated as they leave fishing zones.

Using computer simulations, we also found that a significant number of FADs are deployed in the eastern Pacific Ocean, left to drift so they have time to aggregate tuna, and subsequently fished on in the Western and Central Pacific Ocean. This complicates matters as the eastern Pacific is managed by an entirely different fishery Commission with its own set of fisheries management strategies and programmes.

Growing human populations and climate change are increasing pressure on small island nations. FAD fishing is very important to their economic and food security, allowing access to the wealth of the ocean’s abundance.




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We need to safeguard these resources, with effective management around the number and location of FAD deployments, more research on their impact on tuna and bycatch populations, the use of biodegradable FADs, or effective recovery programs to remove old FADs from the ocean at the end of their slow journeys across the Pacific.The Conversation

Joe Scutt Phillips, Senior Fisheries Scientists (Tuna Behavioural Ecology), Secretariat of the Pacific Community; Alex Sen Gupta, Senior Lecturer, School of Biological, Earth and Environmental Sciences, UNSW; Graham Pilling, Principal Fisheries Scientist, Secretariat of the Pacific Community, and Lauriane Escalle, Fisheries Scientist, Secretariat of the Pacific Community

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

Curious Kids: which is smarter – a blue whale or an orca?



Blue whales and orcas are both specialists in their own way. You can’t really measure which one is more intelligent.
Shutterstock

Kerstin Bilgmann, Macquarie University

If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au.


Which is smarter: blue whales or orcas? – Prasaad, age 6.


There’s no simple answer. We don’t know for sure which one is smarter, because not everyone agrees on what “intelligence” means.

It’s true that blue whales and orcas (also called killer whales) are both smart. They both have very large brains. Orcas have particularly large brains compared to their overall body size.

But it’s not just about brain size. When it comes to measuring intelligence, we might also consider things like:

  • the number of nerve cells in the brain;
  • ability to navigate the deep, wide oceans;
  • solving difficult problems;
  • communicating;
  • working in teams.

Let’s look at which animal is good at which skill.




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What can a blue whale do?

There’s no doubt a blue whale is a very intelligent animal.

Blue whales eat krill, which are very tiny prawn-shaped animals that gather in huge swarms that are often far away from where blue whales give birth to their children. Despite the distance, blue whales are masters of finding krill. They are very good at navigating along coasts and across the deep, wide oceans.

In fact, blue whales are so smart they can work out if a swarm of krill is worth chasing. Blue whales are very good at finding krill that are fat and in big swarms so they do not waste their energy catching smaller swarms. Blue whales catch krill by rolling on their side and opening their mouths. It is a lot of work and they have to use a lot of energy to do it.

Blue whales also have excellent systems for communicating with each other.

What can an orca do?

Orcas are a kind of large dolphin and they have different strengths.

They are very good at working together. They form groups and hunt together for fish or other sea mammals – including whales. This is why they are called “killer whales”.

They are also expert communicators and have their own language – even certain noises that are used by a particular group of orcas to show they are in the group.

Orcas form groups and hunt together.
Shutterstock

They both are very intelligent in their own way

Some scientists have wondered if you could measure intelligence by looking at how well animals teach their children how to behave – for example, how to find food, fight or stay safe.

Orcas are masters at teaching their children exactly what to do. This involves things like hunting in groups or sneaking up on a seal and grabbing it before sliding back into the water.

However, blue whales are also good at teaching their offspring skills such as long-distance navigation – in other words, finding their way around the vast oceans.

Both blue whales and killer whales have their own special behaviours and skills. We really can’t say which one is more intelligent because both are very intelligent in their own way.




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Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.auThe Conversation

Kerstin Bilgmann, Lecturer in Biological Sciences, Macquarie University

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

Misogyny, male rage and the words men use to describe Greta Thunberg



Greta Thunberg departs after speaking at the youth climate strike in Battery Park, New York.
Peter Foley/EPA

Camilla Nelson, University of Notre Dame Australia and Meg Vertigan, University of Newcastle

Detractors have dismissed Swedish climate activist Greta Thunberg – a Nobel Prize nominee – as mentally ill, hysterical and a millennial weirdo after she pleaded with world officials last week to address the climate crisis.

Here, two researchers explain the stereotypical labels deployed by critics to undermine Thunberg’s call to action, which the activist herself has described as “too loud for people to handle”.

Camilla Nelson, Associate Professor in Media, University of Notre Dame

Greta Thunberg obviously scares some men silly. The bullying of the teenager by conservative middle-aged men has taken on a grim, almost hysterical edge. And some of them are reaching deep into the misogynist’s playbook to divert focus from her message.

It is not a rhetorical accident that critics of Thunberg, nearly 17, almost always call her a “child”. This infantilisation is invariably accompanied by accusations of emotionality, hysteria, mental disturbance, and an inability to think for herself – stereotypically feminine labels which are traditionally used to silence women’s public speech, and undermine their authority.

In Australia, Herald Sun columnist Andrew Bolt has called Thunberg “freakishly influential … with many mental disorders”. Sky News commentator Chris Kenny described her as a “hysterical teenager” who needs to be cared for.

Overseas, male commentators have used similar pejorative terms – describing her as a “mentally-ill Swedish child”, unstable and a “millenarian weirdo”. One claimed Thunberg needed a “spanking”; another likened her activism to “medieval witchcraft”.

Obviously these men find Thunberg triggering. But why?

Thunberg attends a Senate climate change taskforce press conference in Washington.
Shawn Thew/EPA



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At a deep level, the language of climate denialism is tied up with a form of masculine identity predicated on modern industrial capitalism – specifically, the Promethean idea of the conquest of nature by man, in a world especially made for men.

By attacking industrial capitalism, and its ethos of politics as usual, Thunberg is not only attacking the core beliefs and world view of certain sorts of men, but also their sense of masculine self-worth. Male rage is their knee-jerk response.

Thunberg did not try to be “nice” when she confronted world leaders at the United Nations last week. She did not defer or smile. She did not attempt to make anybody feel comfortable.

US President Donald Trump tweeted: “She seems like a very happy young girl looking forward to a bright and wonderful future. So nice to see!” Happiness here aligns itself with conformity, and an unspoken idea that women and children are expected to be docile and complacent.

But in reality, Thunberg is cutting through – rather than displaying – emotionalism. What certain kinds of men do not wish to acknowledge is that asking for action on climate change is entirely rational.




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Meg Vertigan, lecturer in English and writing and academic advisor at the University of Newcastle

As Greta Thunberg’s speech to the UN climate summit last week reverberates across the world, claims by critics over her mental state are alarming. Thunberg has described herself as having “Asperger’s”, an autism spectrum disorder, and describes it as her “superpower”.

But politicians and broadcasters appear to have confused the disorder with mental illness – a label used throughout history to label and potentially stigmatise “difficult” women who are told they need bed rest, medication or incarceration. Even today, doctors are more likely to diagnose women than men with depression, even when they present with identical symptoms.

Advocates for people with autism have pointed out the disorder is not linked to mental illness.

Yet commentator Andrew Bolt wrote of Thunberg, “I have never seen a girl so young and with so many mental disorders treated by so many adults as a guru”.

“She seems chronically attracted to apocalyptic visions, to fear,” he wrote, describing her as “chronically anxious and disturbed”.

Thunberg is ‘not the messiah, she is an extremely anxious girl’, Bolt says.

Not-for-profit organisation Beyond Blue defines anxiety as stress or worry which occurs “without any particular reason or cause”. Therefore by diagnosing Thunberg with anxiety, men are pathologising Thunberg’s concern about the environment and dismissing her fears as baseless and the result of mental illness.

History is littered with examples of this. Former Coalition minister George Brandis in 2015 famously called Labor frontbencher Penny Wong “shrill” and “hysterical” after she interjected during his Senate address – implying her comments were due to feminine mental instability.

So too, Australian Prime Minister Scott Morrison suggested climate change fears were a type of pathology. Following Thunberg’s UN speech he declared that the climate debate subjected children to “needless anxiety” and suggested they needed more “context and perspective” on the issue. “We’ve got to let kids be kids,” he said.

Here, Morrison is implying that Thunberg’s anxiety is somehow contagious. This is offensive to people with anxiety disorders – and offensive to passionate and vocal women.The Conversation

Camilla Nelson, Associate Professor in Media, University of Notre Dame Australia and Meg Vertigan, Lecturer in English and Writing/ Academic Advisor, University of Newcastle

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

The showy everlasting is endangered, but a primary school is helping out



The showy everlasting is being grown at Woodlupine Primary School.
Andrew Crawford, Author provided

Leonie Monks, Murdoch University; Alanna Chant, and Andrew Crawford

Western Australia boasts seemingly endless fields of pink, white and yellow everlasting daisies. But while there might seem to be an infinite number, one species in particular is actually endangered. The showy everlasting (or Schoenia filifolia subsp. subulifolia) once grew in the Mid West of WA. Now it is found in just a few spots around the tiny inland town of Mingenew.

But a WA primary school is helping my colleagues and me save the beautiful showy everlasting. With new seed banks, a genetic project and a whole lot of digging, we’re hopeful we can keep this gorgeous native daisy around for the next generation.




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A grower and a shower

The first European to collect the showy everlasting was eminent botanist James Drummond, most likely in the mid-1800s. Initially the species was placed in the Helichrysum family (a group of plants also known as everlastings), but in 1992 botanist Paul Wilson formally described the species based on a specimen collected from Geraldton.

The genus name Schoenia is in honour of the 19th-century eye specialist and botanical illustrator Johannes Schoen, and the species name filifolia refers to its long, slender leaves.

Showy everlastings retain their colour long after they’re picked and dried.
Andrew Crawford, Author provided

Everlastings get their name from the fact that that the flowers hold their colour long after they have been picked and dried. The species is known as the showy everlasting because its large, brightly coloured flowers put on a spectacular show when in bloom.

The showy everlasting is an annual plant, growing around 30cm high, with long narrow leaves. Its bright yellow flowers bloom from August to October. The showy everlasting has two closely related sister species: the more common Schoenia filifolia subsp. filifolia, found throughout the WA Wheatbelt, and Schoenia filifolia subsp. arenicola, which grows around Carnarvon but hasn’t been collected for decades. The main differences between the showy everlasting and its sister species are the much larger flowers and the shape of the base of the flower, which is hemispherical rather than vase-shaped.




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Collections of the showy everlasting housed in the Western Australian Herbarium indicate the species was once more widespread. It’s likely land clearing for farms and infrastructure led to the disappearance of the species from much of its known range.

It was listed as endangered in 2003. At that time the species was found in just three locations. At each of these sites, threats such as chemical drift from nearby agricultural land, grazing by animals, competition from weeds, and increasing soil salinity were all jeopardising the survival of the species.

Unfortunately, by the late 2000s two of these three populations had succumbed to these threats and were lost. However, continued search efforts since then have uncovered two new populations. The showy everlasting is hanging on, but a concerted conservation effort is needed to ensure its survival in the wild.

New populations needed

To ensure the long-term survival of the showy everlasting, we need to establish new populations – a process called translocation.

As an insurance policy, in 2007 seeds were collected and frozen in the Threatened Flora Seed Vault at the Western Australia Seed Centre. In 2015 my colleagues and I used some of these seeds in small-scale translocation trials, successfully getting new plants to grow, flower and seed in three small populations.

Despite this success, we knew the populations would need to be much, much larger and we would need many more populations to ensure persistence of the species. And for that we needed more information about the showy everlasting’s biology, and larger amounts of seed.

Currently a genetic study is underway to look at the difference between the showy everlasting in different locations and its sister species. As part of my PhD study with Murdoch University, I am running a glasshouse experiment to see whether different populations of the showy everlasting can cross and produce viable seed, and whether there are benefits or risks to such crosses.

The initial translocation trials have proved we can successfully establish new populations, but we’re currently limited by the amount of available seed. This is because our trials showed the most efficient way to establish the showy everlasting is by planting seeds directly into the ground. However, this process uses a lot of seeds – more than we have stored in the Seed Vault. Rather than denude the wild populations, we needed a new source.

Fortunately, at this time Andrew Crawford, manager of the Threatened Flora Seed Vault at the Western Australian Seed Centre, was approached by the principal of the Woodlupine Primary School, Trevor Phoebe. He was looking for a meaningful way to involve his students with plant conservation. This led to the establishment of a seed production area at the school which aims to grow and harvest seed of the showy everlasting. The students at the school are involved with planting, monitoring and taking care of the plants, and will help collect the seed when they ripen.




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It is still early days for this project, however early signs are promising. Seedlings have established well and have begun flowering. Seed collection is planned for later in the year.

The seed harvested will be used in the future to boost plant numbers in the existing populations, and to establish new sites, hopefully securing this beautiful species in the wild so that everyone can enjoy the showy everlasting for decades to come.


Do you love native plants? Sign up to The Conversation’s Beating Around the Bush Facebook group.The Conversation

Leonie Monks, Research scientist, Murdoch University; Alanna Chant, Invited User, and Andrew Crawford, Research scientist

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