Tag: Invasive Species

The Lionfish is one of the latest invasive species to threaten large-scale destruction of habitat within the US.

Invasive species are defined as populations of living creatures that have been transported from their natural habitat and become established in another ecosystem perhaps thousands of kilometers away. Sometimes this movement is a natural occurrence, such as when a few finches were somehow blown onto the Galapagos Islands, became established and evolved into some fifteen recognized species. Indeed such rare but natural transplanting of species is considered to be a driving force in evolution as the relocated population adapts to its new environment.

The 15 Species of Finches inhabiting the Galapagos Islands are all descended from a few finches that somehow survived being blown to those distant islands. (Credit: Pinterest)

More often however it is human beings who have transported the creatures either intentionally or accidentally. One example of the latter category would be the common salt water aquarium fish the lionfish, any member of the 12 species of the genus Pterois but particularly P volitans and P miles. See images below.

Pterois volitans, the Red Lionfish is a popular aquarium fish that should only be kept by a very experienced hobbyist. (Credit: Wildlife Society)
Pterois miles is another popular species of Lionfish. (Credit: Enalia Physis)

Lionfish are native to the Indian and western Pacific oceans where they are a predatory species feeding on small fish and invertebrates. Adult lionfish are generally 20-40cm in length and can weigh more than a kilogram. Their numerous spiny fins and colourful stripes have made them a popular aquarium fish, even though the animal’s spines are venomous and can produce a painful sting along with vomiting, nausea, convulsions and numerous other ill effects. Because of the danger of their spines Lionfish should only be kept by the most experienced of aquarium Hobbists.

The natural home for lionfish are the blue (P miles) and Green (P volitans ) shaded regions. They are a destructive, invasive species in the red areas. (Credit: USGS)

  Even though lionfish are popular pets it appears as if some aquarium keepers along Florida’s Atlantic coast must have decided that they were more trouble than they were worth and decided to release their pets into the ocean. Once free the lionfish began doing what fish do and without their natural predators the lionfish population has exploded. Lionfish are now regularly found along the US coastline from Cape Hatteras in North Carolina to Texas and throughout the Caribbean islands.

The destruction caused by lionfish consists mainly in their preying on native species, particularly on the young fish of valuable game species. It is estimated that the increasing lionfish population could lead to a reduction of 80% in the biodiversity of Gulf and Caribbean coral reefs.

To combat their spread government and private conservation groups are developing programs to eradicate the lionfish from the waters they are now infesting. Currently biologists and fishermen are working to develop special traps and even robotic hunters that will catch lionfish without harming native species. At present however the most efficient technique for dealing with lionfish is spearfishing by scuba divers.

Spearfishing is presently the best method for controlling the population of these predators. (Credit: Deeperblue.com)

One helpful fact is that lionfish are quite tasty if you fillet them properly; remember they are venomous. So if oceanic scientists do actually develop a technique for large scale culling of lionfish don’t be surprised if someday you see lionfish offered at your local fishmarket.

Broiled Lionfish with Paprika and Herbs

Until then contests and fishing tournaments are being organized to increase interest in harvesting lionfish all along the eastern and gulf coasts. The Florida Keys National Marine Sanctuary has even gone so far as to license divers to hunt lionfish within its boundaries, a thing almost unheard of for a wildlife sanctuary.

Poster for a lionfish catching tournament. (Credit: The Woody Foundation)

Eventually lionfish will simply become a normal part of the marine environment along the southern US coast. In time other animals will learn to prey on them and that will impose a control on their population. In fact it appears that sharks may be immune to the lionfish’s venom, some scientists are even trying to teach sharks to prey on lionfish.

How much damage the lionfish will do to the biodiversity of the Gulf and Caribbean before then however can only be guessed at right now.  A lot of trouble because of a few people who didn’t want to take care of the animals they bought thinking that they looked really cool!

The Robots are Coming: To Kill!!

This is my fourth post concerning the increasing use of artificial intelligence (AI), and drone technology in activities that used to require human beings to accomplish (see posts of 2Sept2016, 12Feb2017 and 17Jun2017). I have talked about driverless cars, automated warehouse workers and other developments in robotics. Today I’m going to talk a bit about two independent efforts to develop automated drones that are actually intended to kill living creatures.

Now don’t panic, we’re not talking about some military funded program to build terminator type robot soldiers. In fact the animal targets in both programs, and we are talking about animals here, are invasive species that are doing great damage in the ecological systems into which they’ve been introduced. And as it happens both species are sea creatures.

The first robotic hunter I’ll talk about is being developed by the Worcester Polytechnic Institute (WPI) to eliminate a species known as the Lionfish (Genus Pterois) from the coastal waters off Florida. See the image of a Lionfish below.

The Lionfish, Genus Pterois (Credit: Live Science)

The lionfish is a native of the Red Sea and eastern Indian Ocean and is considered as a prized possession among saltwater aquarium hobbyists, I’ve had several friends who have owned one. The long spines the animal sports are actually poisonous although the poison is usually not fatal in humans.

Several lionfish kept in aquaria must have been released into the waters off Florida and without their native predators their population has exploded much to the detriment of native species. The lionfish is itself an active predator and specimens have been dissected to find hundreds of juvenal native fish in their bellies. Over the past several years scuba divers in Florida have been actively hunting lionfish not only because of the damage to the ecosystem the fish is causing but also because lionfish are quite tasty and fetch a good price of up to $40 per kilo.

Human drivers can only do so much however, our time underwater is limited and lionfish are known to dive considerably deeper than is safe for the average scuba diver. So that’s where WPI’s robotic lionfish killer comes in, see image below.

Lionfish Hunting Robot being developed at WPI (Credit: Digital Trends)

On the left hand side of the robot can be seen the revolver-like carriage of eight spear tips with orange foam. The foam is intended to bring the spear to the surface so that it can be recovered and the fish harvested, it’s worth $40 per kilo remember. To the right of the spears are two small boxes containing cameras. Behind the upper camera is a chamber containing the electronics while behind the lower camera is a tank to control buoyancy.

“The goal is to be able to toss the robot over the side of the boat and have it go down to the reef, plot out a course, and begin its search (for lionfish),” according to Craig Putnam who is senior instructor in computer science and associate director of WPI’s Robotics Engineering Program.

On the other side of the world a similar solution is being developed to help protect the corals of the Great Barrier Reef off Australia. The enemy species here is not a fish but a species of invertebrate known as the Crown of Thorns starfish (Acanthaster planci), see image below.

Crown of thorns starfish (Credit: JSTOR Daily)

The crown of thorns moves slowly over the coral, ingesting the small polyps that make coral a living rock. The starfish have grown so numerous that large sections of the reef have been devoured, destroying the habitat of hundreds of species of fish and other creatures.

In the same way that WPI is developing a robot to hunt down lionfish here it is the Queensland University of Technology (QUT) who have developed the Crown-Of-Thorns-Starfish Robot (COTSbot) to help protect the reef. See image below.

COTSbot hunting Robot (Credit: Business Insider)

Unlike the lionfish the starfish is not desirable, and it moves much more slowly making the COTSbot’s job a good bit easier. In fact the COTSbot patrols the reef, spots a starfish with 99% accuracy and injects it with a poison to kill them.

The success of both of these two programs depends finally on the ability of computer systems, of AI to recognize their intended target. Whether such systems can be reliable enough to be trusted to act autonomously in a complex ecosystem is still a open question.

It’s true that both of these programs are intended to restore an out of balance ecology. It’s also true that neither program has any connection to the military so we’re not discussing anything like the Terminator. Or are we, after all these are computer controlled robots designed to kill living creatures without any human supervision. Anyway you put it that just doesn’t sound right to me. Or have I just been reading to much Science Fiction.

 

Giant Carnivorous Worms are Invading France. No, that’s not the Plot of the Latest Disaster Movie.

Before you get too frightened the ‘Giant’ worms invading France are less than half a meter in length and while they are meat-eaters they mostly eat other, more familiar worms. However that doesn’t mean that they aren’t a big problem.

What we’re talking about are Hammerhead Flatworms, see images below. Creatures that are native to Asia but that have been unintentionally been brought to Europe and have now become established in southern France. This news raises two important issues, how human activity has enabled invasive species to harm environments around the world and, what do we actually mean when we talk about worms?

Diversibipalium multilineatum (Credit: Live Science)

Bipalium kewense eating an Earthworm (Credit: Live Science)

I’ll consider the second issue first. We humans tend to call any small creature that is long and narrow with no noticeable appendages, legs or head or etc., a worm. Now the typical earthworm that we can dig up in our backyard and use as bait when we go fishing is a species, in fact an entire class of species within the phylum Annelid, the segmented worms, see image below.

Common Earthworm, Lumbricus terrestris, Segmented Worm (Credit: Mira.com)

While Annelid worms may look simple on the outside they are really rather complex creatures with a full range of internal organs including both a circulatory and respiratory system. Indeed the internal structure of the segmented worms is so similar to that of the Arthropods, insects and crustaceans etc., that the two phyla are considered to be evolutionary cousins.

On the other hand the animals invading France are Flatworms, members of the phylum Platyhelminthes which are far simpler creatures having no internal body cavity at all. Without either a circulatory or respiratory system flatworms have to be flat because every cell in their body has to be near its skin surface in order to get its oxygen from the outside world.

So from now on we should all bear in mind that ‘worm’ can really mean a lot of very different animals, segmented worms, flatworms and oh, there is an entire phylum of roundworms as well.

So now let’s consider the problem of species of animals that ‘ride along’ with human beings as we travel around the world. These creatures often establish themselves in new environments were they have no natural predators to keep them in check so they breed out of control and end up destroying many native species. Examples of this phenomenon are so numerous I’ll only mention a few.

Before humans came, the island of Guam had no snakes so many of the species of birds there evolved to nest on the ground. Once Humans brought some snakes as pets a few got loose and within just a couple of decades all those birds were extinct, which actually hurt the snakes themselves as they had destroyed their own food source.

Right now the Asian carp is an invasive species spreading throughout the Mississippi river region and that are now threatening to get into the Great Lakes. The carp simply crowd out more valuable, well to us more valuable, native fish species destroying both recreational and industrial fishing wherever they spread. Also the carp have the habit of jumping out of the water whenever they are startled which has actually caused injuries to a few people. The image below shows how violent this habit can be.

Asian Carp (Credit: NPR)

The surprising thing about the Hammerhead Flatworms in France is that gardeners in southern France have been telling the ‘smart’ professional biologists about the flatworms for a couple of decades but the professionals weren’t really listening. Yes, the scientists admitted, some of these animals could hitch a ride on shipments of vegetables and fruit from south Asia but they couldn’t survive in France’s colder climate. This is one actual case where the professional scientists should have paid more attention to the ordinary, average person.

And the Hammerhead Flatworms are more than a slight embarrassment, they do real damage. You see the native segmented worms are responsible for a lot of the aeration and mixing of the soil we use for agriculture. Studies have shown that fields without earthworms are as much as 10% less productive.

Since the Hammerhead Flatworms can quickly decimate the earthworm population in an area we could be dealing with a very big problem. Any program to eradicate the flatworms would be very expensive and would probably still have little effect. Scientists are at least now determined to keep a closer watch on these creatures to see how quickly and how far they spread along with getting a better idea of the damage they do.

We like to think that we rule this world and take advantage of other creature for our purposes but the Hammerhead Flatworms are just one more example of how other species can sometimes take advantage of us for their purposes.