Ideas and Information from a Maui Perspective

Eliminating Alien Species and Land Mines

By Steve Rose
Thursday, October 24, 2002

A Practical Solution for Ship Ballast Pests

There is a serious problem with alien species being introduced into distant waterways by the ballast discharge of foreign vessels.  The introduction of zebra mussels in the Great Lakes are an example of a such a problem. 

Alien species are introduced because the boat must take on ballast after discharging its cargo, and the water from the port is what is used for ballast.  By the same token, that water has to be discharged to take on more cargo at the other end of the journey.  Organisms in the water go for a free ride

Several systems are being tested in an attempt to overcome the problem (filtering, poisoning the water, replacing fresh water ballast with salt water midway through the voyage, etc.).  Unfortunately, all systems so far are too expensive (e.g. retrofitting ships with purification equipment) or turn out to be ineffective (e.g. organisms that can adapt to the salinity).

It seems that the solution would be to provide land based holding and processing for ballast water. It could be done on less expensive real estate near but not necessarily in the harbor area. Retrofits on existing ships would be limited to a coupling from the output of the ballast pumps. No limit on the rate of discharge or type of purification would be imposed, as the processing happens later. The processed water could be discharged safely, or used (as a goodwill gesture) as ballast for ships that were unloading. This also avoids the need for midocean exchange of ballast water, which in fact is dilution rather than exchange and may have unforseen consequences of its own.

A Marginal Solution for the Detection of Alien Terrestrial Species

It would be possible to build autonomous roving “robots”, solar powered, reporting via wireless, with enough on board intelligence to detect alien plants and animals.

Such an autonomous device could use many means of detection and locomotion, and built inexpensively enough that hundreds could be deployed.  It would be possible to interact with them when a report was received to verify what was detected.

For example, on Maui, we have several alien species that have become a problem in the “wild”:  Axis deer, introduced for hunters, can now be found in large herds (e.g. 100 animals), and have become an agricultural pest (aside from eating endangered native vegetation, and spreading introduced plants).  Goats, pigs, and rabbits are also a serious problem.  Banana Polka and other large plants threaten our forests (Tahiti’s native forests have been largely destroyed by Miconia, a smothering vine).  While the brown tree snake has not found its way to Hawaii, Guam now has more than 5000 per square mile, and their native birds have been decimated (aside from other problems).

An autonomous roving identifier would use video, audio, odor sensing, and chemical tests (even DNA profiling for plants) to sense and determine the identity of its targets, using onboard processing power.  It would then report its results by wireless to a monitoring facility.  It would also report its precise position using GPS technology.  Its means of locomotion would be determined by the terrain where it was to be deployed.  For animal detection, it might not even need to be mobile.  When its energy runs low, it would enter a dormant phase while its batteries were recharged via its solar panel.

How practical is this, and how much might something like this cost?  Suitable miniature video cameras are about $50, the wireless connection could be cellular or directional 802.11b, GPS adds about $50 or may be built in to a cell phone used to provide the data interconnect.  All in all, with the processor, rechargeable batteries, mechanism, solar panel, etc. it would probably cost about $500 each in small quantities.  However, it might allow the complete control of some alien species for which there is no adequate answer now.

A Low Tech Approach to the Discovery and Elimination of Land Mines

No single solution will solve the worldwide land mine problem.  Many of the solutions proposed or in use are very expensive.  In some circumstances, though, at least an initial pass could be accomplished with a very inexpensive mechanism deployed in great numbers, depending in part on randomness for thorough coverage.

There is a children’s toy that consists of a plastic ball covered with blunt rubber spikes, that has an internal motor spinning an off-center weight that causes the ball to wobble and bounce around at random, much to everyone’s amusement.  Picture a “heavy duty” version of the ball, capable of landing with enough force to detonate a land mine.  When the ball lands on a blunted spike, its mass is concentrated over a small area, increasing its effective force.  By definition, the ball would be destroyed in a resulting blast, but the ball could be manufactured for a few dollars, so that would not be an issue.  This device would be used in large numbers, and they could be dropped, thrown, or propelled onto a minefield at random.  Their movements would also be random, but with enough balls over a long enough period, the clearance could be very thorough.  Other, more expensive and capable equipment would then be used to insure 100% removal.




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