That Fish Blog – Aquarium Advice and Information

They came from foreign waters. With stealth, appetite, and agility on their side, they’ve become one of the most successful invasive species in recent history, and realistically, the invasion has only just begun. Their deadly and dizzying beauty is of little consolation to those following the invasion of the Volitan Lionfish.
About a year ago, Dave posted a blog on lionfish as invasive species and the responsibility of aquarists to not release non-native species into waterways. Brandon has followed up with similar articles on some other invasive non-native species, too. Just this week I came across 2 more recent articles about the lionfish invasion, this time about populations established in the Caribbean and off the coast for Florida. I wanted to bring you the articles and an update, as the problem is only getting worse as we could have predicted.

Both articles pinpoint the beginning of the problem as six specimens that escaped into open waterways from a Miami waterfront aquarium that was smashed during hurricane Andrew in 1992, though it is highly likely that there were other contributions, too. It is becoming a serious concern as the predators multiply, their numbers in the thousands, and devastate native populations. The articles liken the invasion to a plague of locusts. NOAA studies show that the populations in some areas have increased tremendously, from 22 per hectare in 2004 to 200 per hectare in 2008. The predators are having a huge effect on commercial fish populations and populations of herbivores that keep algae and other marine vegetation at bay, especially on reefs.

As the drama unfolds, it really is compelling to read about, and it will be interesting and scary to see what will happen in the next couple of years if there are no solutions found to keep the populations in check. Scientists are scurrying to find natural predators of lionfish to aid in control, and they’re encouraging fishermen and restaurants to utilize them as entrees. It’s open season on these fish in many places, but with such huge numbers and range, the outlook is bleak for control…disturbing on so many levels.

http://blogs.thatpetplace.com/thatfishblog/2007/11/07/invasive-species-volitan-lionfish/
http://www.timesonline.co.uk/tol/travel/news/article4538370.ece
http://www.timesonline.co.uk/tol/travel/news/article4538370.ece

Until next time, Patty

Please welcome back Brandon Moyer with another entry on invasive species

The next species I would like to present to you in my exploration of invasive species is one that is notorious among biologists across the country. Though it is quite beautiful in bloom, it is known as a super invasive plant species that disrupts habitats and displaces many native species of fish as well as insects, birds, and other small mammals.

The species is Lythrum salicaria, and it may be something you see every day without even knowing it.  It is known by over ten common names including spiked loosestrife and purple lythrum worldwide, but is best known by the name Purple Loosestrife in the United States. Purple Loosestrife was first introduced into North America through several different vectors; as an ornamental plant for ponds and gardens, as an herb used in cooking and medicine, and through ship ballast water. The origin of Purple Loosestrife is unknown, although its current range is vast. It is very hardy, has spread across Asia and Europe, only limited by the extreme cold of the upper northern hemisphere.

Purple Loosestrife spreads in two ways. One adult plant (4+ years of age) can produce over two million seeds in a single season. These seeds tend to float which aids in dispersal. Their rhizomes, commonly known as runners, can grow up to a foot a season. New plants can spring from these rhizomes, which compounds the number of seeds produced each season.

In several biology and ecology courses I had taken at Millersville University, L. salicaria was a popular example of an introduced species that has taken a strong foothold in a new environment. The dense clusters of roots and rhizomes choke out the roots of other plants around the loosestrife, increasing the area in which it can spread and smothering native plants. Their leaves decompose in the fall when the weather begins to cool and detritivore activity decreases, leading to nutrification of infested waterways. Its thick undergrowth deprives native animals like turtles of areas to bask, but is not dense enough to protect other animals from predation.

Today you can see purple loosestrife almost anywhere you see water in the eastern United States including bogs and drainage areas around warehouses and malls. It can be found in every state except for Florida, Hawaii, and Alaska. Conventional methods of eradicating the invasive, including herbicides and burning, are ineffective. One interesting method of control, considered biological control, is introducing other non-native species that prey on the invasive species. In the case of Purple Loosestrife, leaf beetles, root boring weevils, and flower and seed eating weevils have all been introduced to help stop the spread of the weed.
In any case, control is necessary to protect the complex ecosystems of the wetlands that Purple Loosestrife dominates.  You can help by first learning to identify loosestrife, then using methods to control the spread of this invasive species if you find it on your property by digging, pulling, spot spraying or cutting the plants while they are in bloom and before they seed, usually June-Early August.  Remove the plants and cuttings in plastic bags so they degrade, or incinerate the remains of the plants in a contained area.  It is not recommended that they be composted.  Also, avoid certain cultivars of garden loosestrife and their seed, though they may not be invasive varieties, many may be able to cross pollinate with the invasive species.

For more information on Loosestrife visit the following sites:
http://www.invasive.org/eastern/biocontrol/11PurpleLoosestrife.html
http://www.npwrc.usgs.gov/resource/plants/loosstrf/index.htm
http://dnr.wi.gov/invasiveS/fact/loose2.htm
http://www.seagrant.umn.edu/ais/purpleloosestrife_info

Image referenced from Wikipedia http://en.wikipedia.org/wiki/Image:Purple_loosestrife2.jpg, first posted by Megger and used under the GNU Free Documentation License

Thanks Brandon,

Until Next Time,

Dave

Please welcome back Brandon Moyer for another excellent post.

We carry hundreds of different species of fish and inverts here at That Fish Place, That Pet Place that come from all around the world.  There are, however, certain species that are no longer available to us by act of law.  Their release into the wild and the lifestyles and behaviors they exhibit has earned them the title of invasive species.  This blog is the first in a series of popular invasive pet species accounts.  One of these is commonly inquired about here at That Fish Place and is notorious worldwide.

The Northern Snakehead, Channa argus, is one species of fish that has been introduced into non-native waters where it has thrived and disrupted its new habitat.  The snakehead family originates from Asia and parts of Africa.  The Northern Snakehead, which is invasive in the United States, originates from Southeast China and Korea.  Snakeheads are apex predators, meaning that they stand at the top of the food chain and eat almost anything they can get in their mouth.  Females can release anywhere from 1,300 to 15,000 eggs during a single spawn.  They can spawn up to five times in a single year.  They can survive in waters which range in temperature from 0 to 30 degrees Celsius.  What makes them more threatening is that they can survive out of water for four days by breathing air with modified organs, even longer if they construct a muddy burrow.

The first invasive snakehead in the United States was discovered in Spiritwood Lake in California in 1997.  The first established population of snakeheads was found in Crofton, Maryland in 2002.  This population provided proof that snakeheads were able to invade and flourish in US waters.  Since then juvenile and adult snakeheads have been found in the Schuylkill River in Pennsylvania, Lake Wylie in North Carolina, Meadow Lake in New York, and several other states in the eastern United States.  When snakeheads enter a new body of water they tend to disrupt the food chain.  Juvenile snakeheads compete for food with juveniles of native species.  Adults also compete for resources with adults of native species and become so aggressive that they will also kill and eat them.

Their aggressive behavior, distinct appearance, and large size made snakeheads a popular aquarium fish, although due to their potential to invade natural ecosystems, they are illegal in over half of the United States, including Pennsylvania, Maryland, and New York.  Irresponsibility was the main cause of their invasion into US waters.  We as responsible aquarists must realize the impacts that snakeheads, and many other species of fish, may potentially have in the wild to prevent these species turning from pets to pests.

I hope that this blog was informative and illustrated the importance of keeping our pets in the aquarium.  Check back for more invasive species blogs. Photo courtesy of the U.S. Geological Survey.

Thanks Brandon!

Until Next Time,

Dave