Curious Kids: how would the disappearance of anglerfish affect our environment?



Anglerfish have an enlarged fin overhanging their eyes and their mouth that acts as a lure – much like bait on a fisherman’s line.
Shutterstock

Andy Davis, University of Wollongong

Curious Kids is a series for children. Send your question to curiouskids@theconversation.edu.au. You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.


How would the disappearance of anglerfish affect our environment? – Bella, age 6, Sydney.


As I am sure you know, anglerfish live deep in the ocean. The females have an enlarged fin overhanging their eyes and their mouth that acts as a lure – much like bait on a fishing line – and this explains their name. (“Angling” is a method of fishing.)

The fact is we understand very little about the deep sea and how its inhabitants, including anglerfish, will respond to change. In fact, more people have walked on the Moon than have been to the bottom of the ocean.

But I will do my best to answer your question.




Read more:
Curious Kids: how do creatures living in the deep sea stay alive given the pressure?


The food web

Close your eyes and imagine a spider’s web. All parts of it are connected, and if a bug gets tangled in one part, it can cause a completely different part of the web to wobble or break.

It helps to remember that all species are interconnected via something called the “food web”. The food web is not a real web like a spider’s web. It’s just a way of thinking about how species are connected to each other. Basically, the food web tells us who eats whom.

If you make a change to one part of the food web, that can have an ripple effect that can cause changes on another part of the web.

Here’s an example of a food web (not every animal is included in this one, but you get the idea).
Shutterstock

Less of one animal can mean more of another

Anglerfish usually eat small fish, as well as relatives of shrimp.

It is likely that if all the anglerfish in the ocean disappeared, their prey would explode in number and another predator would then “step in” to replace them.

And any species that likes to eat the anglerfish would have to start eating another species instead – or risk dying out.

At the height of the whaling industry, about 100 years ago, whales nearly disappeared. That meant that the number of krill (the tiny animals that whales eat) exploded, providing a feast for other animals that also eat krill – such as seals. That is how a food web works.

Weird and wonderful

There are around 200 different types of anglerfish. Although one giant species grows to over a metre, most anglerfish are tiny – less than 10cm long.

Only female anglerfish have lures. These lures often glow in the dark, thanks to the bio-luminescent bacteria inside them, which presents a tempting (but fake) meal to their unsuspecting prey.

Anglerfish don’t form large schools like many other fish and this represents a problem for them – they need to find a mate. The tiny males have found a solution: if they do happen to find a female, they grasp onto her with their mouths and never let go.

These males tap into the females’ blood stream and never have to eat again. Scientists call this behaviour parasitic. Sometimes more than one male can be attached to a single female. Imagine someone’s father being 100 times smaller than their mother and being permanently attached to her.

Nature is truly weird and wonderful.

This picture shows the larger female has two smaller parasitic males attached to her body to fertilise her eggs.
Shutterstock



Read more:
Curious Kids: How was the ocean formed? Where did all the water come from?


Threats

Among the biggest problems for a lot of fish species are disease and overfishing by humans. But it’s highly unlikely that these threats could wipe out anglerfish.

Anglerfish are found between 300 and several thousand metres of water. At this depth, it is constantly dark and the water is cold.

As they live in such deep water and do not form schools, they are not targeted by fishermen, a common threat for many shallow water fish.

And anglerfish are so widely spread across the world’s oceans that any disease is highly unlikely to spread among them.

There is one threat that might affect angler fish – the threat of global warming. Temperatures in the deep ocean are very stable, they simply don’t change much.

Anglerfish live their entire lives at depth with near constant temperatures; hence even small shifts in temperature may affect them. It remains unclear whether increasing temperatures really will threaten angler fish – only time will tell.


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Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.The Conversation

Andy Davis, Director – Institute for Conservation Biology and Environmental Management, University of Wollongong

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

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Antarctica: Ice Melt is Alarming


The link below is to an article reporting on the effects of climate change in Antarctica, with the Filchner-Ronne Ice Shelf almost certainly doomed and a catastrophic ice melt in consequence of its disappearance.

For more visit:
http://www.sciencenews.org/view/generic/id/340580/title/Big_Antarctic_ice_sheet_appears_doomed

Malcolm Naden: Barrington Tops Warning for Travellers


Travellers to the Barrington Tops are being warned that outlaw and modern bushranger Malcolm Naden is suspected of hiding out in the remote wilderness area. There is currently a $50 000 reward for information that leads to his capture. He is the most wanted person in New South Wales, suspected of being involved in the disappearance of his cousin Lateesha Nolan and the murder of Kristy Scholes in 2005 at Dubbo.

Naden has sought refuge in the bush in the region bordered by Dubbo in the west and Kempsey in the east since 2005. During this time he has broken into homes, stealing non-perishable food items, camping gear and other equipment required to survive the bushland in which he hides and lives. He is known to be an expert bushman.

Naden first hid in the Western Plains Zoo at Dubbo and has since been known to have been in the vicinity of the Barrington Tops. In 2008 he was known to be in the vicinity of Stewarts Brook, in the western Barrington Tops area. In January 2009 he was known to be at Bellbrook, west of Kempsey. Three months ago he was known to be at Mount Mooney, in the northern Barrington Tops. It is thought that he is also responsible for similar break-ins around the Mount Mooney area in late August 2010. There have been a large number of break-ins across the region this year. He is believed to be armed, with a rifle having been stolen in one of the break-ins. Not all of the break-ins are confirmed as being committed by Malcolm Naden, but they all seem to bear his signature.

According to local newspapers, it is also believed that kangaroo carcasses have been found in the Barrington Tops, butchered in an expert manner. Naden was an abattoir worker and similar carcasses were found at the Dubbo zoo when Naden was hiding there.

The area in which Malcolm Naden is thought to be hiding was once the hideout for the bushranger known as ‘Captain Thunderbolt.’ Naden seems to be following in Thunderbolt’s footsteps in more ways than one.

For more on Malcolm Naden visit:

http://www.police.nsw.gov.au/can_you_help_us/wanted/malcolm_john_naden

http://coastmick21.blogspot.com/

http://www.smh.com.au/news/national/police-seek-man-on-run-after-cousin-found-dead/2005/08/21/1124562750384.html

http://www.australianmissingpersonsregister.com/Naden.htm

http://www.brisbanetimes.com.au/news/national/wanted-man-and-a-town-in-fear/2009/01/17/1232213416486.html

http://www.facebook.com/topic.php?uid=4884239637&topic=7725

http://www.theherald.com.au/news/local/news/general/danger-at-the-tops-break-ins-point-to-fugitive/1928579.aspx

http://www.smh.com.au/nsw/publics-help-sought-over-murder-cases-20100904-14v5u.html

CROCODILE ATTACK: HUMAN REMAINS FOUND IN CROCODILE


A 4.3m long crocodile has been caught and tested following the disappearance of Arthur Booker in the Endeavour River near Cooktown (Queensland, Australia) two weeks ago. Male human remains have been found within the crocodile and police have been notified of the find. DNA tests are now to be carried out to confirm the identity of the human remains, though it is more than likely to be those of Arthur Booker.

TRAPPED CROCODILE NOT KILLER: Cooktown


The first crocodile trapped in the hunt for a crocodile that may be responsible for the disappearance of Arthur Booker in the Endeavour River near Cooktown in Queensland was not responsible for his disappearance.

The crocodile has now been set free and tests will now be carried out a further two crocodiles that have been caught.

CROCODILE ATTACK: TRAPPING BEGINS NEAR COOKTOWN


The body of Vietnam veteran Arthur Booker, of Logan, Queensland, has still not been found following a suspected crocodile attack earlier this week. It is thought that Booker was taken by a large crocodile while checking crab traps along the Endeavour River near Cooktown on Tuesday. All that has been found in the search for the missing 62-year-old man has been his footwear and watch.

The search for Booker has now entered a new stage with police suspending their search of the river. Queensland Environmental Protection Officers (EPA) have now begun to lay crocodile traps in the area so that crocodiles can be examined for remains without harming or killing them.

The investigation into the disappearance of Arthur Booker has yet to determine if he was in fact taken by a crocodile, although this remains the most likely scenario.  There are a number of large crocodiles inhabiting the area, including the 6m ‘Charlie.’

Charlie is known to be responsible for the loss of pet dogs, livestock, eating a 3.5m crocodile and was once seen taking a horse.

The probable crocodile attack has once again brought the call for crocodile culling back into the public arena. At the moment any thought of culling by officials has been dismissed.

BELOW: Footage reporting the disappearance of Arthur Booker

 

MYSTERY SOLVED: PLANE IS THAT OF STEVE FOSSETT


There is now more information on the story I posted yesterday regarding the disappearance of Steve Fossett at:

https://kevinswildside.wordpress.com/2008/10/02/steve-fossett-mystery-solved/

The wreckage discovered during the renewed search for Steve Fossett (following the discovery of several items belonging to Steve Fossett by a bushwalker) has turned out to be that of the missing Steve Fossett. Human remains have also been found in the wreckage with DNA testing to be used to confirm whether the remains are indeed those of Steve Fossett.