[http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2012/01/07/BA9Q1MLHHG.DTL&type=science]
Santa will make one final swoop through the Bay Area today, bringing gifts to some of the region's tiniest, most helpless residents.
Volunteers plan to drop about 1,000 leftover Christmas trees into a lake in Fremont to create a habitat for baby fish, who have been struggling for years in Bay Area reservoirs.
"We're jump-starting the ecosystem," said Jon Walton, owner of Walton's Pond fishing tackle shop in San Leandro, one of the event's sponsors. "This helps the entire food chain, from microorganisms to the great blue heron."
The project is led by the East Bay Regional Park District, which has been collecting Christmas trees every January for about 20 years to give to the fish. Volunteers tie the trees together with rope and drop them to the lakebed.
The trees provide two services: a place for juvenile bass, sunfish, bluefin and other fish to hide from predators and a food source for a variety of critters that live in and around the lakes. Algae grows on the tree limbs, bugs live in the algae, fish of all sizes eat the bugs, and birds eat the fish.
The program has had a huge impact on the East Bay's reservoirs, said the park district's fisheries manager, Pete Alexander. Most of the reservoirs are man-made and have fluctuating water levels, making underwater plant life almost nonexistent. Lack of underwater vegetation leads to a dearth of bugs and habitat for smaller fish.
The district continually stocks the lakes, but ideally would like more fish to reproduce and sustain their populations naturally.
Christmas trees are a key part of that process, he said.
"We're essentially taking a two-dimensional habitat and making it three-dimensional," Alexander said.
In the lakes where the district has already dropped Christmas trees - Del Valle, Chabot and the Quarry lakes - biological diversity has increased dramatically, he said. Del Valle, for example, in Livermore, now has a plethora of osprey, herons, kingfishers and river otters, due in part to a healthy fish population. There are even some bald eagles.
The Christmas tree idea originated with the California Department of Fish and Game at least 20 years ago, and has been successful at reservoirs throughout the state, said Dave Highland, Fish and Game fish habitat specialist.
"With a lot of these man-made lakes, you're left with lakebeds that look like the surface of the moon," said Highland. "So people started at looking at ways to create habitat so fish could make it to adulthood."
Today, Rainbow Lake in Fremont will be the Christmas tree beneficiary. Because the lake level is low, volunteers will drag the trees to the exposed lake bed. When the rains come, the trees will become submerged.
The trees are donated by Christmas tree vendors. The district can't use trees donated by the public because they often contain stray bits of tinsel, flocking or chemicals added to keep the trees green.
Douglas firs make the best fish habitat because they're the bushiest, Alexander said. The trees generally last five years underwater before they disintegrate, and the park district drops in another batch.
Fishermen have seen a noticeable difference in the Christmas tree-laden lakes.
The fish are bigger, healthier and more plentiful, Walton said.
That's why he, his staff and customers are regular volunteers at the annual Christmas tree drop.
"We noticed over the years that the juvenile fish weren't surviving because they're prey - they had nowhere to hide," he said. "So we thought we'd better start putting some habitat back in the lakes. It's a chance for us to give something back to the fisheries."
Joe Sullivan (left) and Joshua Porter unload some of the 1,000 Christmas trees at the edge of Rainbow Lake in Fremont. Volunteers will help with many more today.
Michael Macor / The Chronicle
Cinder blocks, hold down Christmas trees when water levels are higher in the spring and summer months, that have been placed some eight years ago, at the Quarry Lakes Regional park, in Fremont, Ca. on Friday Jan. 6, 2012.
Photo: Michael Macor / The Chronicle
Pete Alexander, district fish manager, on Friday Jan. 6, 2012, walks along a line of Christmas trees that have been placed some eight years ago, which are underwater during the spring and summer months, at Rainbow Lake at Quarry Lakes Regional Park, in Fremont, Ca.
Photo: Michael Macor / The Chronicle
A Heron along a line of Christmas trees, on Friday Jan. 6, 2012, that have been placed years ago at the Quarry Lakes Regional Park, in Fremont, Ca.
Photo: Michael Macor / The Chronicle
Joshua Porter unloads some of the 1,000 Christmas trees at the edge of Rainbow Lake at Quarry Lakes Regional Park, on Friday Jan. 6, 2012, in Fremont, Ca.
Photo: Michael Macor / The Chronicle
No comments:
Post a Comment