Creatures From The Venice Lagoon.(The Arts)(marine species)

Byline: Barbie Nadeau

Jetties constructed to shore up the sinking city have created a surprising explosion of marine wildlife.

Most people visit Venice with basic essentials like a camera, a guidebook and smart togs for a romantic night out--plus maybe Wellington boots in the likely event the piazzas are flooded. But now visitors to the City of Love should also consider packing scuba gear. Ongoing work to construct artificial reefs and floodgates to keep Venice from turning into a modern-day Atlantis has produced an unlikely side effect: a fast-growing, underwater paradise with 250 species of flora and fauna, rivaling even the most teeming Caribbean dive spots.

This reef isn't coral; it is made of concrete and rubble, affording abundant nooks and flat surfaces for plants and crustaceans to grow. They in turn lure more fish to feed, benefiting the local fishing industry and creating an unusually vibrant and varied ecosystem for these waters. "We are surprised by the rapidity and strength of these new colonies," says Andrea Rismondo, a marine biologist who coauthored a study for the Society for the Ecology of the Lagoon and Coast. "It is amazing that we are seeing this sort of diversity and opportunity for diving in the north Adriatic."

In addition to providing a new scuba-diving venue, the Venice lagoon's accidental reef offers a valuable opportunity to study biodiversity as it develops. Rismondo says that invasive algae and foreign fish are doing battle against native species. And even fish commonly found in this area are reproducing more quickly and living longer. Not only that, thanks in large part to global warming, nonharmful species commonly found only in warmer waters are doing well in the ecosystem created by the artificial flood barriers and jetties. For the first time, the world's largest bivalve mollusk, the Pinna nobilis, normally found only in the Mediterranean Sea, is thriving in the Adriatic. The mollusk survives only in good-quality water--a clear indicator of the health of the sea in this area, despite the potential for pollution from the ongoing construction. Also now present in this part of the Adriatic: the giant medusa, a 60-centimeter jellyfish never before seen in these waters. Commercial species are also multiplying, from edible oysters to a new, permanent biomass of nearly 600,000 kilograms of mussels--more than double what existed less than a decade ago.

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