Natural Perspectives

Vic Leipzig and Lou Murray

We built a pond 18 months ago. I use the term “we” loosely since I dug

the hole, laid the vinyl liner, carefully placed every rock and set up

the pump and waterfall. Vic offered advice, most of which I ignored, on

where and how I should dig. Basically he helped by staying out of my way.

Our long, narrow pond now looks like a lovely natural stream bed

slicing diagonally across our front yard. Having this pond has been an

interesting experience and a mixed blessing.

We were thrilled with the bird species it attracted. Wilson’s

warblers, black-headed grosbeaks, yellowthroats and black phoebes checked

things out from the safety of our Western redbud tree before taking a dip

in the waterfall. Several species of colorful dragonflies flitted over

the water all summer long. Tadpoles came in with the pond plants. They

grew legs, became identifiable as Pacific tree frogs and took up a noisy

residence in our liquid amber trees. A Cooper’s hawk bathed in the pond

nearly every day last winter.

The pond also attracted a pair of mallards, but the ducks didn’t stay

long enough to raise a brood of ducklings. However, they did leave us

with an unwelcome addition to the pond’s wildlife palette -- microscopic

flatworms. Therein lies a tale.

One night about a year ago, raccoons woke us up with soft purring

sounds. I looked out the window and spotted two big ones waddling along

the fence. I wondered why they were making such happy, contented noises.

I should have guessed.

When we checked our pond in the morning, we discovered all the water

hyacinths were broken. Sadly, our two, 9-inch pet goldfish were missing.

Scales and fish innards littering the ground told the tale of their fate.

All the smaller goldfish were gone as well. The rocks lining the stream

bed were knocked askew and the rock grotto was dismantled.

I had worked so hard getting the pond to look just the way I wanted

it. I actually felt violated. With a great sigh, I took off my shoes and

socks and waded in up to my knees. I replaced the rocks along the side of

the stream and thought my misfortunes were over. I was wrong.

The next day I was covered from toes to knees and fingers to elbows

with itchy, red bumps. Vic, a professional zoologist, quickly diagnosed

my rash as swimmers itch and told me more than I wanted to know about a

nasty little parasite called a schistosome.

This microscopic critter uses ducks and other birds as a host. When

the ducks pooped in the pond, they dumped in a load of larval flatworms.

The schistosomes then infest snails as the next host in their life cycle.

When they leave the snails, they try to burrow into the skin of the first

warmblooded animal that they find, preferably a duck or goose, travel

through the bloodstream to the liver and begin their cycle anew.

Fortunately, these flatworms are unable to penetrate human skin all

the way to the bloodstream. Unfortunately, they burrow in a short

distance and die, causing an allergic reaction. Meanwhile, the human host

-- that would be me -- itches something awful and looks worse than a

cutaneous anthrax victim. At least anthrax can be treated. There is no

treatment for swimmers itch other than cortisone cream or calamine lotion

to relieve the itching.

When the pond needed cleaning last week, I dreaded it. I did not want

to go through that itchy experience again, so I suited up like a

Washington DC postal worker. I donned rubber boots and long latex gloves

before venturing into the septic soup. Vic reassured me that I was well

protected, but I didn’t see him jumping in. I longed for a full haz-mat

suit.

I emptied most of the pond, pulled out the pump and handed it to Vic

along with a pair of rubber gloves. While he cleaned the pump and

biofilter, I replaced rocks knocked into the pond from countless raids

over the last year by opossums, raccoons and skunks.

It took all day, but we finally got the pond put back together and

disinfected our work area with bleach. The waterfall runs more swiftly

now and the excessive plant growth is weeded out. We could kill the

snails with copper sulfate and get rid of the schistosomes that way, but

we don’t want to do that. Snails are an important part of our pond’s

ecosystem.

We’ve long since given up trying to keep goldfish and are satisfied

with mosquitofish. They earn their keep by eating all the mosquito

larvae. They probably also eat dragonfly larvae and tadpoles, but our

pond, like much of life, is a trade-off. We accept some bad along with

the good.

By the way, you’ll be pleased to know that my biocontainment efforts

worked. We did not come down with swimmers itch.

* VIC LEIPZIG and LOU MURRAY are Huntington Beach residents and

environmentalists. They can be reached at o7 vicleipzig@aol.comf7 .