Invasive Species Case

Posted by on Jan 08 2009 |



One goal for our time at SCOPE is to develop a case to use for the adapt/adopt portion of the
BMMB Workshop. We are starting with a case developed by JAP (UD) for a course in mathematical
modeling. The staging for this case consists of two parts. In the first stage, students are given the
following two newspaper articles:


Copyright 2004 The Christian Science Publishing Society  
Christian Science Monitor (Boston, MA)

August 19, 2004, Thursday

‘Frankenfish’ and the hunt for invasive species

By Patrik Jonsson Correspondent of The Christian Science Monitor


Tearing across the Potomac in his bass boat, Maryland’s top snakehead hunter is on a mission: to bolster his reputation.

Cliff Magnus caught the nastiest keeper of his life this summer, up in the tight tidal channel of Little Hunting Creek, along a row of Washington cottages with their gardens and sea walls. It was a US-record-setting northern snakehead – an invasive species colloquially known as the Frankenfish, or The Fish That Ate Maryland – weighing almost 6 pounds and measuring 25 inches long, nearly 10 inches longer than the escaped fish that stirred America’s gothic imagination two years ago.

Since then, snakeheads have slithered not just into the national consciousness, but into Washington’s waterways: At least 17 have been caught this summer along a 14-mile stretch of the Potomac, as well as in a Philadelphia pond.

The hunt for Frankenfish has spawned “wanted” posters, a fishing tournament, and small-scale fame for those who’ve caught them, like Mr. Magnus, a former lumberjack and race-car driver turned professional fisherman, and Tom “Snakehead Slayer” Woo, who’s caught three. But beyond the tide of local interest, snakeheads are drawing attention to the proliferation of invasive species mucking up American fauna nationwide.

The problem, say critics, is that not every invader is an enemy, and the fallback pattern of all-out war can muddy the waters still further.

Today, the US spends some $ 137 billion annually to combat nonnative species from fairy-tale creatures to John Carpenter monsters – including filter-clogging zebra mussels, South American fur rats, and the beautiful but destructive mute swan, which has devastated sea-grass beds on the Chesapeake while bullying native birds. At present, the snakehead is low on this ecological totem-pole, with no real proof of overwhelming damage.

“We’re dealing with this never-ending onslaught of new invasive species that accompany the globalization of trade, commerce, and travel,” says Jonathan McKnight, an associate director at the Maryland Department of Natural Resources. “Right now, the snakehead has become the poster fish, but we need people to make the connection between all invasive species and the real ecological damage that they do.”

To be sure, the arrival of foreign species isn’t always catastrophic. But biologists are increasingly realizing that some newcomers overwhelm an area’s natural balance, devastating natives and transforming ecosystems.

Despite the nation’s zero-tolerance alert for invasive species, public perception varies widely, to the consternation of wildlife managers. The homely snakehead has few friends. But animal-rights groups have come to the defense of the mute swan, which 4 out or 5 Marylanders are in favor of forcibly culling, and it may take an act of Congress to change the Migratory Species Act so that wildlife managers can reduce the flocks.

“The snakehead is a science-fiction monster and the mute swan is a fairy-tale creature – you see my dilemma,” says Mr. McKnight.

But Magnus, for one, isn’t backing down in his mission to do battle with the snakeheads. “No, they’re not going to eat every bass in the river and then attack your children at the bus stop,” he admits. “But the Potomac River is today one of the most popular bass fisheries in the nation” – and 10 years from now, he says, a proliferation of snakeheads could make for a very different waterway.

Not everyone shares Magnus’s approach, and critics say that although the annihilation of invasive species may seem like an easy solution, it’s hardly realistic. In fact, some say the state’s refusal to consider more pragmatic solutions may ultimately stymie efforts to control invaders: A plan to force people to kill their pet snakeheads, for instance, may lead to more releases.

When Ruth Hanessian of the Maryland Invasive Species Council suggested that officials hand out snakehead recipes to promote the catching and eating of the fish, she was rebuffed. Ms. Hanessian is also sensitive to what she sees as the state’s hypocrisy. After all, she says, when Maryland drained Pine Lake to capture one snakehead, officials made no provisions for saving other lake inhabitants. Hanessian transferred several koi from the lake to a backyard bathtub.

“Many of the species in question are in fact purposely introduced, frequently by state and federal agencies,” she says. Autumn olives, she points out, were obtained from the state for wildlife planting. “But we have now gone 180 degrees, so that anything not native is now dreadful. To stop an invasive exotic species is admirable, but is it possible?”

Still, the snakehead may not be quite the monster it appears. Officials doubt that the fish actually “walks,” though it can live out of water for several hours and may be able to slither from waterway to waterway. Many Asian cultures rather enjoy the snakehead, salted and grilled, and some cultures even release it as part of religious rituals.

Indeed, though the Potomac snakeheads may be hemmed in by the salty Chesapeake Bay, they’re already showing signs of leaving the state, which can happen when eggs stick to boats and “goose bottoms,” says Magnus. Several females caught this summer have been pregnant, and a Smithsonian research team is investigating whether the fish caught in a south Philly pond two weeks ago are related to the Potomac crew.

Meanwhile, the chase is on, with teams of Virginia wildlife biologists tucking electric contraptions and rubber worms among the lily pads.

When Magnus brought his record snakehead home to his shop-worn suburb in Waldorf, Md., half the neighborhood showed up along with bigwigs from Maryland DNR. Though the fish had been out of the water and in a cooler for four hours, it still had plenty of life and onlookers oohed and aahed.

Today, he’s at it again, flipping a glittery worm up against the weed beds and under the floating docks, chronicling strange stories and misadventures, usually starring himself.

Still, the record-sanctioning International Game Fish Association won’t be adding a snakehead category any time soon. The state of Maryland, however, has not yet ruled out what may at this point be the most pragmatic reaction: Handing Magnus the line-class state record for the northern snakehead, America’s most wanted game fish.


Invasive species in most Great Lakes ships
Survey sampled 42, found potentially deadly organisms in two thirds

The Associated Press

Updated: 9:13 a.m. ET April 20, 2005


MUSKEGON, Mich. – Oceangoing freighters that claim to be empty of ballast water before entering the Great Lakes routinely carry organisms that endanger the water bodies, a new report shows.

The ships often have saltwater algae, invertebrates, deadly bacteria and other organisms in muddy water at the bottoms of their ballast tanks, according to the study conducted by the University of Michigan and the National Oceanic and Atmospheric Administration shows.

Ballast water is stored below deck to keep ships stable. It is added or dumped based on cargo load and organisms can escape from the ballast tanks when ships in harbor take in or unload water.

“Many invasive species act like a computer virus. Once they get into the Great Lakes ecosystem they can clean it out,” said Cameron Davis, executive director of the Chicago-based Alliance for the Great Lakes. “In the Great Lakes, we are operating without a virus protection program.”

Authors of the study, reported in Tuesday’s editions of The Muskegon Chronicle, called for immediate action to stem the flow of exotic organisms and pathogens into the lakes.

Researchers found that two-thirds of 42 ships sampled for the five-year study carried potentially deadly organisms in ballast tanks that were supposedly empty and clean, including cholera and cryptosporidium, the newspaper reported. In 1993, cryptosporidium from an unknown source contaminated Milwaukee’s drinking water system, killing more than 100 people and making 400,000 others ill.

Zebra mussels and 181 other species imported to the lakes threaten to drive out some native species at the base of the Great Lakes food web, endangering a multibillion dollar fishery.

Despite the potential threat and their calls for action, however, researchers cautioned that contaminated ballast water may not represent an immediate danger.

“We know there are pathogens in these ships, but we don’t know of any outbreaks of disease associated with ships’ ballasting practices,” said co-author Fred Dobbs, an oceanography professor at Old Dominion University.

The authors said one possible remedy would be to require all transcontinental freighters to completely empty and refill ballast tanks with salt water before entering the Great Lakes.

Michigan lawmakers are considering legislation to require shipping companies to obtain a ballast water discharge permit before operating in Great Lakes ports.

© 2005 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

© 2005

Students are then given the following handout and the instructor leads a discussion:


Invasive Species


Quick Fact

One study estimates that the total costs of invasive species in the United States amount to more than $100 billion each year.



          Attached are two recent newspaper articles discussing the effect of invasive species (Jonsson 2004; Press 2005). Read each of these articles and then discuss the following questions in your group.


1.     What problems do invasive species cause?

2.     What are the probable consequences of leaving these problems unchecked?

3.     What costs are associated with battling the invasive species problem? What costs are associated with leaving it alone?


Next, together with your team, attempt to formulate precise questions that an invasive species researcher might want to address and that can be addressed through mathematical modeling. Pick the two most interesting and clearest problems. One person from your group will give a quick presentation of the basic problem, consequences, and your best ideas for using mathematical modeling to explore the issue of invasive species.


Jonsson (2004). ‘Frankenfish’ and the hunt for invasive species. Christian Science Monitor.


Press, A. (2005). Invasive species in most Great Lakes ships.


The second stage consists of a discussion focused on mathematical modeling and prompted by the following

Invasive Species


Quick Fact

One study estimates that the total costs of invasive species in the United States amount to more than $100 billion each year.


You are studying the broad topic of invasive species. Your first task was to formulate as many precise questions as you could that an invasive species researcher might want to address and that can be addressed through mathematical modeling. Let me give you some examples.


1.     Invasive species often compete with native species for resources. Given an initial population of native species, A, and assuming an invasive species, B, under what conditions will B eradicate A? A eradicate B? Coexistence be possible?

2.     Invasive species are often introduced at a very specific location. For example, when a ship releases bilge water, invasive species may be introduced at that location. Given this point introduction into some existing environment, how does the invasive species spread throughout the environment? Under what conditions does it spread?


Today I want you to WRITE out as many ideas as you can. Make them precise. Make them succinct. At the end of the day you must hand in one sheet of problems for your group. Make sure you keep a copy. Pick ONE of your problems and start developing a model to address your questions.


 Next Steps

  • INSERT Pat’s info on Adopt & Adapt here.
  • Examine data sets in detail. (Find partners to help!)
  • Workshop logistics (lodging, money, etc.)
  • Formalize schedule.
  • Develop application form, solicit, and review applications.
  • Find and add modeling/simulation tools.
  • Find/build other cases.


Feedback Question


  • Which mathematical and which biological areas would be of interest to you in such a workshop?
  • Any other thoughts/suggestions?




Resources and Data Sets

3 comments for now

3 Responses to “Invasive Species Case”


    Hey this looks great. Here are a couple of other resources to consider. Both of these are problem spaces that contain background material, datasets and lots of references. There are other pieces of these that are not online – contact me if you are interested in them. -sam

    Identifying Biocontrol Agents Through Applied Systematics

    Tamarix Problem Space

    08 Jan 2009 at 6:50 pm


    cell biology, of course, which you have.

    09 Jan 2009 at 1:03 pm


    Invasive species modeling is a wonderful way to engage adult learners. There are several that tie in nicely with the case…

    09 Jan 2009 at 1:04 pm

Trackback URI |


OER Commons Pittsburgh School of Education
Emory CSE