Handling Invasive Species: studies look at treatment and commercial enterprise

Invasive species continue to pose problems around the world - from relocated fish and land animals to plants to even infectious diseases.  In the oceans, invasive species can prove to be both disruptive to the marine environment and a potential hazard to humans as well.

Two recent scientific studies, one in Emerging Infectious Diseases and the other in Marine Pollution Bulletin, looked at the issue of ballast water that is taken in and released by tankers and freighters in ports all over the globe.  This exchange of water to maintain a safe balance to the ship as it loads or unloads its cargo has introduced a variety of unwelcome guests including mussels, seaweeds and algae, and even cholera.

Sometimes the ballast exchange takes place in deep enough water so that its contents are sufficiently dissipated.  But in shallower water, pathogens as a product of urbanization and sewage can either come aboard or be expelled and soon brought into shore via swells and currents.

One solution is to treat the ballast water on board the vessel.  However, ports and cities are then dependent on the ships having the proper equipment and using the methods effectively to do the job.   The other possible approach is to develop an onshore treatment process wherein the ballast water is pumped ashore for treatment and then pumped back to the ship as needed, rather than having the entire ballast exchange take place in open water.  A better idea perhaps on paper, but it requires  considerable investment in equipment and the design of each port must be carefully studied to determine if and where the systems can be installed.

However, compared to the financial losses incurred by invasive species from disrupted commercial fisheries to clogged water inlet/outlet pipes to disease outbreaks, the costs of advanced onshore treatment systems could prove to be a bargain.

Another study, written up in Conservation Letters, examined the issue of whether consuming an invasive species as a possible food source could prove to be an effective means of populations.  Why beat it, just eat it.

This has been the approach taken in areas where the Humboldt squid has moved in, shifting the fishermens catch from local commercial fish stocks to all squid.  And in the Caribbean and the eastern Florida coast, where the lionfish population has exploded recently from its accidental introduction several years ago, attempts are being made to develop a taste for the South Pacific reef fish's meat among local sharks and even with the human population (a bit tricky to prepare but, I have been told, quite tasty).

The study, however, notes the dilemma that this approach can cause through the production then of a viable market.  An invasive species could turn out to be a commercial success and where there is commercial success there can be the desire to maintain or even expand it.  Suddenly, the invasive species becomes a profitable friend to man - at the expense of the marine environment it is affecting.  The ultimate insult would be that an effort could be made to protect the species for the sake of its commercial value - a complete reversal of the original concept of reducing or eliminating the population through harvesting.

The introduction of commercial enterprise and consumption in the control of any invasive species must be undertaken with a clear understanding by government and regulatory agencies as to the underlying purpose of taking such a step.  Either supported by scientific research or even just the common sense that every invasive species is a Pandora's box of unknown consequences, decisions must be thoughtful and well-informed.

Source: Emerging Infectious Diseases 18(10)
Source: Marine Pollution Bulletin 64(11)
Source: Conservation Letters 5(5)
          

Amazon Fish In Illinois Lake: South American relative of piranha being caught by fishermen

Writing in his Outdoor blog, Grind TV's Pete Thomas noted another example of an aquarium fish potentially becoming an invasive species due to the careless or irresponsible actions of an home aquarium owner.

In the Amazon River there lives the pacu, a relative of the piranha.  The pacu has a similar shape to the piranha but can grow to be much larger, weighing in at over 50 pounds.  And also similar to the piranha are its set of teeth, but with an interesting twist.  They look more like a set of human molars as the pacu primarily feeds on nuts and seeds which it crushes and grinds up with its teeth and powerful jaws.

Because of its piranha-like appearance but less than hostile manner, the pacu pops up in aquariums around the world from time to time.  But as it ultimately outgrows most home habitats, they sometimes find themselves cast aside in local rivers or lakes.  As supposed herbivores, it would possibly seem that the pacu would be a harmless addition, but there apparently are reports of this fish being responsible for the deaths of two men in Papua New Guinea by castrating them - eeyeowch!

So, it is with a measure of concern to city officials, residents and tourists, as we enter the warm summer months, that pacus were reportedly being caught by fishermen in Lake Lou Yaeger in Illinois.  With more and more bathers entering the lake to escape the heat, the possibility of someone being bitten begins to increase.  As Pete humorously reported in his blog, one key lake official was taking a less than alarmist position regarding the pacu.

"Lake superintendent Jim Caldwell, sounding a bit like the Amity Island mayor in Jaws, assured that everything's OK, adding that he has a small swim in the lake regularly.  It was about then that you half-expected the scary theme music to begin playing." 

Responsible home aquarists always consider the repercussions of disposing of any fish - large or small, teeth or no teeth - in local waterways.  Many fish that are sold to fresh and salt water aquarium enthusiasts are, in fact, juveniles only a few weeks old.  This makes them fragile and mortality can be high.  But if the fish survives and thrives, the owner often can find that they have a fish that is soon outgrowing its habitat.

When I was in my junior high school years, I owned several aquariums in which I prided myself in having a dazzling array of fish to impress my folks and the neighbors. (My friends weren't all that interested.  It was a bit nerdish, in an age of pre-computer nerds.)  There was a local tropical fish store which had some nefarious connections and was able to procure for me a pacu, which I didn't have for too long; the poor thing could barely turn around in the tank.  The shop was also able to get me a series of actual piranhas, which are illegal for regular consumers to own, buy, sell, or trade (I'm guessing the statute of limitations has expired).  The laws existed to prevent a piranha from ending up in the local watering hole and, even as a kid, I could appreciate that since one nearly bit my finger when I was cleaning the tank one day.

So, I can understand the fascination that home aquarists can have in owning exotic fish, but there is a very serious side to their activity that demands responsible decision-making.  Many fresh water fish are raised rather than caught in the wild, but some of those fish can grow to be quite large with hungry appetites.  Salt water fish can also be raised but some are caught in the wild and at great harm to the reef from where they came.  Collectors will sometimes use chemicals or poisons that stun the fish for ease of capture.  Unfortunately, the poisons kill the coral and damage the caught fish's internal organs so that it's life expectancy is shortened.

While one can debate the value or purpose of home aquariums, there should be total agreement that transplanted fresh or salt water plants and animals can have unforeseen consequences on marine ecosystems.

Source: Outdoor/GrindTV 

Invasive Species From the Depths: submersible can prove to be method of transport

From time to time, I will bring up the issue of invasive species, most recently in April regarding the armored catfish.  The transference of a species from one ecosystem to another can cover great distances, such as with the lionfish of the Pacific but now growing in numbers in the Caribbean.  Everything from animal larvae to seaweed can be transported via freighters either by attaching to the hull or inside the bilge.
       
Nature can use various mechanisms to keep some species within specific territories; distance, temperature, predators, and the end results of years of evolution that can involve a variety of minute but important factors.  And in some cases there is the natural boundaries established by depth.
             
While ships, planes, automobiles, and even the careless aquarist can be methods of transportation for shallow water of coastal species, plants and animals at depth have a natural barrier to help keep species in place.  But it's not always the case, as was recently discovered with the world-famous submersible, Alvin.
            
As reported in the Conservation Biology journal, Alvin had been conducting deep sea missions around thermal vents in the Pacific when 38 small limpets were discovered attached to the submersible.  Researchers examined the small invertebrates and were dismayed to find that they were actually a species from a different deep sea area of the Pacific, nearly 400 miles away, where Alvin had been previously.
              
The greatest concern with the discovery was the fact that this particular species of limpet, Lepetodrilus gordensis, carries a parasite in as much as 90 percent of the population.  Transferring this animal to other pristine deep sea environments could have disastrous implications.  The researchers were a bit surprised to discover that the limpet had withstood the change of pressure from the deep depths to the surface.
              
Alvin, owned and operated by the Woods Hole Oceanographic Institution, is typically cleaned after every dive, particularly around the equipment used to capture specimens.  Sloppiness is definitely not part of the Woods Hole regimen, so addressing how these limpets managed to slip by is critical.  Discussions are being held to consider more thorough cleaning procedures, including the use of fresh water, which can kill most salt water organisms.
                
Deep water ecosystems, thousands of feet below the surface, are very isolated ecosystems, protected by depth and pressure, and therefore the consequences of introducing new species could be very disruptive.  Researchers can not necessarily guarantee that there will be adverse effects, but it is certainly something that they would prefer not to have to deal with.
                              
"We know from shallow water systems that one mistake can completely change a system," said Dr. Amanda Bates from the University of Tasmania and one of the researchers involved.  "The scientists themselves have to be better at not getting caught up in their research, just taking a step back and making sure that those jobs are getting done."  
                  
Source: Discover Magazine
Source: The Australian          

Armored Catfish: eroding lake shorelines in Florida

The fish pictured above is a Loricariidae, or armored catfish.  As a teen, I had several freshwater aquariums and this particular catfish was a common fixture in my tanks as a bottom feeder and window cleaner as it fed on the algae that would grow on the aquarium glass.  But they were always just an inch or two long, a juvenile (as is often the case with many of the fish in the aquarium trade).  Cute little guy, nosing around scrubbing the small porcelain hard hat diver resting on the gravel bottom. 

However, the beast above is no welcome visitor to the freshwater lakes and streams in southern Florida.  It is another invasive species that the state is having to contend with.  While the beautiful but voracious lionfish plays havoc with coral reef fish populations off the eastern Florida coast and into the Caribbean, the armored catfish, so named because of its tough scales and spiked fins, is damaging fresh waterways by devouring aquatic plant life which causes erosion of the local shoreline by as much as 10 feet.   Full grown adults also  lay their eggs in 18-inch deep, 4-inch wide holes along the shoreline which can pose a hazard to people walking along the water's edge.

In South America, where the armored catfish is normally found, the balance of nature - the level of plant growth, the predators that feed on the catfish - all help to maintain a proper balance in the catfish population and whatever damage it inflicts on local aquatic plant life.  But in southern Florida it is running amok as it already has for several years in Texas waterways.

The armored catfish joins a long list of invasive species that include, in addition to the lionfish, the ravenous snakehead fish in the Northeast, freshwater zebra mussels in the Great Lakes, and the Caulerpa taxifolia seaweed in California, just to name a few.  And as is often the case with these unintended invaders - sometimes the result of being castaway pets or sometimes brought in from distant waters by freighters carrying them or their eggs/spores in the bilgewater - eradicating them can prove to be difficult and costly.  Estimates to correct shoreline erosion and set up various methods to deter the catfish have been as high as a million dollars.

In describing the situation, contractor Chip Collins, owner of Lake Erosion Restoration, said, "One, it's a safety issue.  Two, it's a curb-appeal issue."

"If we do nothing, I think eventually we're going to end up with a sinkhole," said Suzanne Ury, president of the Royal Lakes Homeowners Association.

It's always a difficult decision, deciding on how best to deal with an invasive species.  Will we do more damage in trying to eliminate it, or should nature take its course and over time reach a new balance.  It was mankind's clumsy handiwork that put it into a foreign ecosystem; do we have the ability to correct the situation or make things worse?
   
Source: Florida Sun-Sentinel 

Beauty as the Beast: lionfish invasion in the Caribbean

It is an unfortunate situation when something of beauty is at risk of being destroyed through no fault of it's own. But off the coast of Florida and throughout the Caribbean, that is the fate that awaits the lionfish (genus: Pterois). For all its graceful movement, striking color, and ornamentation, it is, regrettably, an invader that threatens the ecological balance of reef communities throughout the region.

I just returned from two weeks at sea along the shallow banks northwest of Grand Bahama, and with every reef dive I undertook I was guaranteed at least a half dozen sightings of these small Indo-Pacific predators. Known for having a voracious appetite to match its venomous spines, it was reported in one study that a lionfish can consume three-quarters of a reef's fish population in as little as five weeks. Left unchecked, the lionfish threatens the Bahamas' annual $5 billion tourism industry (that's billion with a "B") and nearly half of the island's employment. Bathers can get stung by the lionfish's dorsal spines or divers can find reefs denuded of colorful tropical fish and this can spell economic ruin for many Caribbean nations.

So, how did this all come about? How did a fish found in the South Pacific make its way halfway across the planet? Well, it certainly would need some help, an accomplice or two.

And that would be us.

The lionfish invasion in the Caribbean is a textbook example of invasive species distribution. Because of its beauty, juvenile lionfish are a popular addition to home saltwater aquariums. That is, popular until your other aquarium fish begin to disappear one by one as the lionfish grows and its appetite blossoms.

So, could it have found itself in the Atlantic when a frazzled home aquarist released it into the wild? Possibly, although it has been reported that the pivotal moment may have occurred in 1992 when Hurricane Andrew battered the southeast coast of the U.S., smashing an aquarium tank in Florida, and releasing six lionfish into open sea. Through the 90's, lionfish expansion was slow, but the first one showed up in the Bahamas in 2005. Two years later, the population exploded (some studies have indicated that a possible reason for the lionfish's successful growth is due to its resistance to many of the parasites commonly found in the Caribbean). The invasion was in full force and the war was on.

Over thousands of years, the lionfish found its proper place in the Indo-Pacific as both predator and prey. Groupers and other large fish fed on them, helping to control their numbers. But in the Bahamas, groupers have been overfished, so there aren't enough of these controlling predators to do the job (and even juvenile groupers are at risk of becoming a lionfish's next meal).

NOAA, the National Oceanic and Atmospheric Administration does not mince words when describing the lionfish invasion. "With few known natural predators, the lionfish poses a major threat to coral reef ecosystems in the Caribbean region by decreasing survival of a wide range of native reef animals via both predation and competition," says NOAA's Office of Research. "It was not unusual to observe lionfish consuming prey up to 2/3 of its own length. Results of the experiment show that lionfish significantly reduce the net recruitment of coral reef fishes by an estimated 80%. The huge reduction in recruitment is due to predation and may eventually result in substantial, negative ecosystem-wide consequences. It is also important to note that lionfish have the potential to act synergistically with other existing stressors, such as climate change, overfishing, and pollution, making this invasion of particular concern for the future of Atlantic coral reefs."



While in the Bahamas, I saw signs and posters proclaiming that the only good lionfish in Caribbean waters was basically a dead one. Crew members would regularly dive with short tri-tip spears in hand, looking under reef ledges - a favorite lionfish hangout - and stabbing any lionfish they came upon, leaving it there perhaps to eaten by a scavenging shark.

In fact, several of the crew reported trying to entice Caribbean reef or lemon sharks to feed on a speared lionfish in the hopes that the sharks would develop a taste for the enemy invader. The sharks would have to learn the best approach to avoid a discomforting sting and, in fact, I saw one shark make repeated bites - spitting out the lionfish until it found the right angle by which it could comfortably consume the free meal.

While the lionfish is one of the tropical ocean's most beautiful inhabitants (and one of my personal favorites), as an invasive species it unintentionally poses considerable risk to the Caribbean marine ecosystem. Could a natural balancing mechanism take hold through predation by fish who discover a new potential prey item in their midst? Or will mankind, having been responsible for the lionfish's introduction in the Caribbean in the first place, now have to take extraordinary steps to eradicate this species? To date, the success of the lionfish shows that there are no easy answers, as is often the case with other invasive plant and animals species around the globe.

Read about the lionfish invasion in NPR.org.
Read about NOAA studies of the lionfish invasion.

Invasive Alien Plants: not from Mars, but controversy brews over source of introduction

Botanical gardens - those quiet sanctuaries where folks go to stroll amongst flower and trees, contemplating the fate of the world - or escaping from it for a few precious minutes. Not exactly a place that you would consider as a hotbed of invasive species activity, now would you?

Well, it may not be that extreme but Philip Hulme, a weed specialist at Lincoln University, New Zealand, claims that a large number of invasive plant species can be traced back to botanical gardens or arboretums. Hulme reviewed the history behind 34 of the top 100 invasive plant species as defined by the IUCN. Researching the origins of these plants, Hulme found that over half of them could be traced to botanical gardens. From a horticultural laboratory or garden, winds, temperature, and animals that can distribute seeds - all can play a role in allowing an alien species to gain a foothold.

Just what are we talking about when we say "invasive plant species"? Well, it casts a fairly broad net, ranging from weeds and vines to flowers all the way to large trees. In the right climate and soil environment, many have the ability to propagate quickly and literally push indigenous plants out of the way. This has often happened when exotic tropical plants have been brought into non-tropical forest environments - the tropical plant comes from an ecosystem where many different plant species are thrust together and battle it out for territory. In less competitive environments, these species can quickly dominate.

As expected, the botanical garden community is not particularly pleased with Hulme's research and conclusions. Stephen Blackmore, head of the Royal Botanic Garden Edinburgh, U.K., says that while botanical gardens may have been interested in introducing non-native species - but lax in protocols - in the past, today they are much more mindful of the consequences and that it is home gardeners and the horticultural trade that probably deserve greater inspection.

"I am not saying that that lets botanic gardens off the hook," says Blackmore, adding that botanical gardens today go to great lengths to quarantine new plants to guard against the spread of fungus or disease, and that they are very conscious of preservation and conservation of the local botanical ecology. Botanic Gardens Conservation International, a global network of botanical gardens, is beginning to develop a set of guidelines for how alien or non-native plants should be managed.

Home gardeners and commercial plant shops remain as a possible point of introduction of invasive species, much like the tropical fish stores and home aquarists who thrill at displaying tropical fish and seaweed species until they become to large or too aggressive for the tanks they are in and accidentally end up in local waters, disrupting the balance of an ecosystem. Case in point, the Caribbean invasion by the voracious lionfish, a Pacific Ocean species.

As mankind becomes more and more global in his curiosity and his movements, then the threat of disruption of ecosystems by invasive species - whether accidental or by design - remains high.

Read more about invasive plant species in NatureNews.

Galapagos Islands: WildAid focuses on conservation results

There are places throughout the world that can serve as both a unique oasis of ecological development and a microcosm of the world as a whole. The Galapagos Islands are an archipelago of volcanic islands off the coast of Ecuador that fit that description to a tee. First brought to worldwide attention by Charles Darwin's studies during his 1835 expedition, the islands have been a source of fascination with scientists and, more recently, tourists.

The islands' uniqueness is a result of their isolation, producing endemic species and acting as a perfect laboratory for the study of natural development and the relationships that intertwine to produce healthy marine and terrestrial ecosystems. The islands are known for their marine iguanas, Galapagos tortoises, and several species of birds - including the only tropical penguin, the Galapagos penguin - just to name a few.

To preserve some of that uniqueness, the Galapagos Marine Reserve (GMR) was established in in 1986, covering over 70,000 square miles of surrounding ocean, one of the largest marine reserves in the world.

However, the more troubling and challenging side for the Galapagos is the islands' role as a microcosm of the world: an ecosystem threatened with the imprint of man. From a growing island population and tourism industry to invasive plant and animal species to illegal fishing within the reserve (often for sharks or sea cucumbers to satisfy a demanding Asian market), the Galapagos Islands are besieged from all directions. Island agencies, struggling with limited resources, must turn to outside conservation organizations for support.

One such organization that has taken a special interest in the Galapagos Islands is WildAid, based in San Francisco. Often working in conjunction with other conservation groups, WildAid has been closely involved in the monitoring of fishing boat activity, finding illegal fishing for shark fins and sea cucumbers taking place under the guise of boats supposedly only passing through the GMR. Last year, the ability to monitor boat activity was improved with the installation of a satellite-based vessel monitoring system. WildAid was also instrumental in bringing sniffer dogs to the islands several years ago, trained to smell not only drugs but shark fins and sea cucumbers.

But while enforcement is an important part of conservation, it is equally important to tackle the root, or roots, of the problem. And in that regard, WildAid has worked with several agencies to help island locals with changing their personal economies away from poaching and abusing their natural resources, assisting them with building more sustainable activities. WildAid's efforts towards alternative incomes garnered the organization the UNDP Equator Prize in 2007.

Realizing the impact of the online world, WildAid has worked in conjunction with Good Egg Studios to develop Elf Island Virtual World, where kids of all ages can participate in interactive online game play to track and protect threatened sharks of the Galapagos Islands, thereby learning what is being done and what they can do to preserve these endangered species. The game company merged with Xeko.com recently, expanding their nature and conservation slate of online gaming.

There are other organizations like WildAid, ones that walk the talk, that provide tangible results and are truly making a difference. When you consider showing your support for any conservation organization, understand that they are all well-intentioned but in the final analysis there must something solid backing them up - good words supported by good deeds.

Florida's Immigration Problem: tropical snakes pose an ecological threat

A young alligator lies quietly at the water's edge, momentarily oblivious to its surroundings as it basks in the warmth of the sun beating down. Moving slowly along the river's muddy sand, a boa constrictor silently approaches and then in an instant wraps itself around the gator, one coil after another. Thus begins one of nature's ageless struggles between predators deep in the tropical forest.

Except that it is not a tropical forest, but Southern Florida. And the snake is actually an invader that is disrupting the fragile ecological balance of Florida's Everglades, marshlands, and rivers.

Throughout the world, more and more we are having to contend with invasive species ranging from mussels and seaweed to lionfish, squid, and now, a laundry list of imported snakes. In the fall of 2009 the U.S. Geological Survey (USGS) issued a report listing a total of nine constrictors - including various pythons, boa constrictors, and anacondas - that were considered an ecological threat (5 were listed as a serious risk, 4 listed as medium risks).

An invading species is not out to deliberately hatch some devious plot to takeover new territory. They are typically introduced through the actions of man. Some species are transported in the bilges of large ships, like certain forms of algae and seaweed. Others are allowed to expand their range because overfishing of their natural predators have allowed them to do so, as with the Humboldt squid. And in some cases, the invasion was a deliberate attempt by man to control one problem, thereby starting another.

With Florida's snake invasion, it has come about from the importation, often illegally, of these snakes as pets. Either a snake escapes from its owner or is foolishly released into the wild because it has become unmanageable. While many snakes serve an important predatory role in controlling rodent populations, these tropical snakes have a much broader diet. Finding a comfortable home in Florida's wilderness, their numbers have been steadily growing - these snakes are also quite prolific; significant breeding populations of Burmese pythons and boa constrictors have been recorded in the state.

The U.S. Fish and Wildlife Service (USFWS) is now considering how best to approach the problem. There are several strategies on the table, a combination of which is probably called for:

• Tightening and enforcing importation restrictions of snakes from Southeast Asia, Africa, and South America.
• Increasing penalties for the accidental or deliberate release of snakes currently in captivity or making certain species illegal to own at all.
• Capturing snakes in the wild and, sadly, disposing of them and any eggs found.

Unfortunately, having imposed ourselves on nature as enablers for the planet's invasive species, we are left with the task of imposing ourselves again to hopefully set things right. No easy task, but government agencies have few choices, given what can befall an ecosystem thrown out of balance when unexpected neighbors move in.

“We have a cautionary tale with the American island of Guam and the brown treesnake,” said Dr. Robert Reed, USGS invasive species scientist and coauthor of the report. “Within 40 years of its arrival, this invasive snake has decimated the island’s native wildlife—10 of Guam’s 12 native forest birds, one of its two bat species, and about half of its native lizards are gone. The python introduction to Florida is so recent that the tally of ecological damage cannot yet be made.”

Read a report summary prepared by the USGS.
Use Defenders of Wildlife's email form to voice your concern to the USFWS (5/11 deadline).

Tilapia Aquafarming: new standards to protect the environment

Tilapia is one of the more common seafoods being aquafarmed nowadays. In fact, 75% of this fish that is consumed comes from ocean- or inland-based farms. But, as with much of the aquafarming taking place today, it is beset with challenges that impact the environment - from feed and waste pollution to the threat of invasive species (escaping tilapia).

While there have been several standards of practice instituted in the past, a new set of standards recently put in place by the Tilapia Aquaculture Dialogue (TAD), is purported to be more comprehensive and up-to-date in addressing the many issues faced by this growing industry. TAD is a collective of commercial, scientific, and conservation experts and the new standards cover a wide range of issues that would benefit the environment and the people involved in tilapia farming (some of the farming takes place in developing countries and so employee concerns were also included).

Tilapia aqua farmers who meet and maintain the standards can become certified through a process that will be established and monitored by GLOBALGAP and, ultimately, by the Aquaculture Stewardship Council (ASC) which is currently being created. These new standards are a major step forward because they apply measurable metrics as opposed to more vague environmental "goals."

“We support the tilapia standards because they will help us tell our customers the story they want and deserve to hear – that they are eating tilapia which was raised in an environmentally friendly way,” said Craig Watson, Vice President of Agricultural Sustainability of Sysco Corporation, the largest foodservice distributor in the United States. “And with the ASC in place, we will have the assurance that the standards will be adhered to properly, which will bring credibility and longevity to the standards.”

Regular readers of this blog know that I am an advocate of aquaculture as it potentially can offset or possibly replace the damage caused by open ocean commercial fishing. These standards are an important step towards addressing the challenges aquaculture faces as it grows to meet demand.

Read World Wildlife Fund press release. The press release provides a link to download the complete standards.

Ethical Debate: endangered species vs. ecosystems

Fellow blogger, David from WhySharksMatter, had an interesting post that I thought I would pass along: the ethical dilemma that develops when endangered species are re-located, between saving the species and protecting the ecosystem. Does the re-located endangered species become an invasive species? Does its re-location produce adverse effects in its new environment.

This ties in to the post I put up recently regarding the Desert Tortoise, where re-located tortoises were not necessarily impacting the new environment; rather the tortoises themselves were become victims of predators in their new environment. How can we avoid our "solutions" becoming part of the "problem"?

Here's David's post:

Ethical debate: endangered species vs. ecosystems

2009 August 23

tags: conservation, endangered species, ethical debate

by whysharksmatter

It’s been a long time since our last ethical debate, but I think you’ll all like this one.

At two different conferences I attended this summer, I heard about a hot new topic in the conservation movement. Biologists studying a variety of organisms, from plants to turtles, are debating this all over the world as we speak.

This new conservation technique is sometimes called “assisted migration”, “managed relocation”, and a variety of other names. Regardless of what you call it, the principle is the same. When an endangered species’ habitat is threatened, scientists simply round up all the members of that species that they can find and move them to a similar habitat elsewhere. Here’s the catch… the places where the endangered species are moved to are often NOT part of those species original range. In other words, we are intentionally introducing invasive species!

Though not necessarily always the case, for the sake of this ethical debate let’s assume that the following two statements are true.

1) Moving an endangered species to a new habitat WILL help the endangered species to survive.

2) Introducing new species to a habitat WILL disrupt the ecosystem of that habitat.

The ethical debate here is straightforward… is it morally right to save an endangered species by disrupting another ecosystem with an invasive species?

It is worth noting that as we are debating this on an academic level, it IS happening. Though there are many examples, one hits close to home. A conservation group known as the “Torreya Guardians” is taking what they call “the world’s most endangered conifer tree” and moving it from Florida… to the very forest where Andrew and I spent many happy weeks hiking while at Duke.

Sea Jelly Invasion: Japan's next monster movie...for real

Japanese fishermen working the Sea of Japan are preparing for what has been called "a huge jellyfish typhoon." Swarms of the giant Nomura sea jelly, which can reach six feet in width, have been sighted. They first appeared in large numbers in 2005, poisoning the fish being caught as they were hauled up together in nets. The problem was so severe that salmon fishermen would not go out to sea and lost up to 80% of their income.

While sea jellies can congregate in large numbers normally, the increasing size and frequency of these aggregations is of major concern to fishermen, public officials (public safety), and researchers.

Researchers at the University of Queensland, Australia, reporting in Trends in Ecology and Environment, have theorized that these aggregations can well be due to human activities. Fertilizer runoff can add excessive nutrients which negatively impact many fish species but can allow sea jellies to flourish because of the associated increase in phytoplankton (a primary food source). Then the die off of the phytoplankton blooms produce decomposition that increases bacteria, causing a reduction in oxygen - again impacting fish but sea jellies are better able to survive in low oxygen environments.

Overfishing also can lead to increased sea jelly aggregations. There have been documented cases of sea jelly blooms when fish such as sardines and anchovies, which feed on the same food sources as sea jellies, are overfished, thereby upsetting the balance of food source competition that normally controls species populations. This has occurred in as disparate areas as off the coast of Nambia in Africa to the Black and Caspian Seas.

And finally, sea jelly larvae can be transported in the ballast water of large ships and, as an invasive species, can take hold in new marine ecosystems where plankton-eating fish are being commercially caught in large numbers, providing the sea jelly with a foothold to grow in numbers.

Increasing sea jelly populations can reach a "tipping point" where they overwhelm the ability of predators to control their numbers, while at the same time feeding on the fish eggs and larvae of those very same predators. When that happens, human management of the situation is made extremely difficult. Researchers are recommending that prevention - controlling runoff, avoiding overfishing, better methods for controlling invasive species - would be a better long-term strategy than eradication.

Lionfish and Pythons: invasive species paying the ultimate price

Well, I'm back from a very successful trip to Chattanooga, Tennessee. Hopefully I will have impressed a few listeners before they watch shark television programming that seems to be obsessed with one thing this year: shark attacks.

I caught two interesting news bits on invasive species. The introduction of foreign animal and plant life into an ecosystem can have disastrous effects either on the ecosystem itself - as in the case of invasive seaweeds or predators like the lionfish - or on our man-made infrastructures - like the damage caused to water pipes from freshwater mussels.

1. Speaking of lionfish: their population has been exploding in the warm waters off Florida and the Caribbean, ever since their introduction by aquarists who could no longer care for them at home and released them into the wild. Voracious by nature, the beautiful lionfish was thought to possibly be held in check through predation by larger animals like groupers. While that still may be the case someday, at the moment it's a losing battle. One that has prompted the development of "lionfish tournaments" which have netted as many as 1200+ lionfish in a single event.

2. TIME magazine just reported on a government-sanctioned program to rid the Florida Everglades of exotic Asian pythons - again, introduced into the wild by owners who could no longer manage them at home. These reptiles, like the Burmese python, can reach a length of up to 18 feet and can disrupt the Everglade's predator-prey hierarchy by feeding on everything from small rodents all the way up to the typical apex predator of the Everglades, the alligator. Officials from the Florida Fish and Wildlife Conservation are working with snake experts to round up some of the estimated 150,000 pythons and are considering even issuing bounty hunter permits.

It's a sad price that has to be paid by all invasive species, whether plant or animal, when the result is their wholesale destruction. But the real villain lies with man either through his thoughtlessness, negligence, or perverse need to own exotic animals as pets. And because of it, we must then cover our tracks at the end of a spear or the barrel of a gun.