Huge Numbers Of Threadfin Shad Show at Delta Pumps

The Delta Pelagic (Open Water) Fish Crash Continues

By Dan Bacher

The massive federal pumps that export water from the California Delta to agribusiness on the west side of the San Joaquin Valley entrained (trapped) over 370,000 threadfin shad, a major forage species on the Delta, in one week.

On one day, October 16, Bureau of Reclamation biologists observed 250,000 shad in collection buckets in the pumping facilities. After collecting the buckets, the federal workers put the fish into a tanker truck and released them into the Sacramento and San Joaquin rivers.

“We were able to salvage most of the fish and get them back into the Delta,” observed Jeff McCracken, spokesman for the U.S. Bureau of Reclamation, dismissing an earlier media report that some of the fish had to be buried.

McCracken said the large number of shad being taken in one week occurred when large schools of shad moved into the area of the Delta pumps, resulting in the entrainment of the introduced species.

“We feel that we do successfully return most of the entrained fish to the Delta alive,” said Ron Silva of the U.S Bureau of Reclamation. “However, we haven’t assessed the survival rate of the threadfin shad because it is not a listed species like delta smelt, king salmon, steelhead or green sturgeon. In our salvage operations, we focus on the listed species, with the exception of one species, striped bass."

The salvaged fish are released at two sites – the San Joaquin River at Antioch and the Sacramento River at Sherman Island.

“From our observations, we suspect that most of the shad successfully reenter the Delta. We know there are losses due to handling and predation, but what it is is anybody’s guess,” said Silva.

He noted that the Bureau increased its salvage hauls to the Delta and has added salt and oxygen to the water to reduce stress and improve the mortality rate for the fish.
“Our charge is to save the fish and put them back into the Delta,” he said. “We usually don’t see the amount of shad that we did last week.”

The capture of the fish stirred up concern among fishery groups because the shad is one of four pelagic (open water) species on the Sacramento-San Joaquin Delta that have experienced a sharp decline since 2001. Angler Mike McKenzie disagreed with the Bureau’s assessment of the shad’s survival rate once returned to the water.

“The shad are taken from the bucket and dumped into a tanker truck, hauled over to Sherman Island and alternatively dumped into the Sacramento or the San Joaquin rivers where there are congregations of squawfish (Sacramento pike-minnows), black bass and striped bass, who eat most of them," said McKenzie.

McKenzie said that Bay/Delta Stamp Committee and the Striped Bass Stamp Committee have both been working on a better way of doing this so-called "salvage operation" because the same thing happens to stripers, salmon, steelhead and all other game fish in the delta.

“We have so far been stymied by the federal and state bureaucracies, including the U.S. Fish and Wildlife Service and DFG,” noted McKenzie. “There is a very good way to increase their survival by simply dumping them into net pens and let them get acclimated and the towing them around while they release them. It’s a ‘no-brainer’ and all of the fisheries biologists agree, but we can't get the management side to make a commitment to doing this,” he added.

Federal and state scientists working on the Pelagic Organism Decline (POD) Team have pinpointed three causes of the decline of the four species – increases in Delta exports, toxic chemicals and invasive species. Since 2001, the state and federal governments have exported record amounts of water out of the Delta amounting to an increase of over 1,000,000 acre feet of water per year.

The Department of Fish and Game introduced threadfin shad to the Delta in 1959 to serve as a forage species for gamefish. A hardy fish, the shad thrived in the sloughs and river channels and became one of the Delta’s most abundant fish. Anglers fish threadfin shad for bait to entice stripers, while they use threadfin pattern lures to catch both stripers and black bass throughout the Delta.

“Given the many human made connections between the Delta and numerous other reservoirs in both northern and southern California, the Threadfin shad is now one of the most widespread fishes in the lower elevation waterways of the state,” writes Samuel M. McGinness in “Field Guide to Freshwater Fishes of California. “Because of its ability to withstand salinities near that of sea water, it is also found throughout San Francisco and San Pablo Bays.”

However, biologists on the POD team became alarmed in May 2005 when this fish’s decline on the Delta paralleled that of the native delta smelt, protected under the federal and California Endangered Species Act. Scientists were concerned that even hardy, adaptable fish like the threadfin shad were on the decline.

This decline continues, according to the latest data available, the September midwater trawl survey by the DFG. “We’re in the midst of a continuing collapse in the pelagic species,” said Bill Jennings, executive director of the California Sportfishing Protection Alliance.

The survey estimates abundance and distribution of fish based on an index number that only makes sense in relation to previous data. The threadfin shad population index for this fall’s survey was 80, making it the second worst lowest population level in the forty years the DFG has concluded the survey.

The Delta smelt index was the third lowest in 40 years, with an abundance index of 9. “It is significant that the smelt were also found further down the Delta than they have been previously, having moved to Suisun Bay and Carquinez Strait,” said Jennings.

The index for juvenile stripers was the third lowest on record, 32. As is the case with the Delta smelt, the majority of stripers were found in Suisun Bay and Montezuma Slough, further west than they have been historically. “Something happening in the Delta is chasing the fish out of it,” said Jennings.

The longfin smelt also had one of its poorest years ever also, with only one fish (an index of 2) captured in Carquinez Strait. This contrasts with just last year, a wet year, when the index was 1563.

Three conservation groups, the Bay Institute, Center for Biological Diversity and Natural Resources Defense Council, in August asked the U. S. Fish and Wildlife Service to list the Bay-Delta population of longfin smelt under the federal Endangered Species Act. At the same time, they asked the California Fish and Game Commission to list the species statewide under the California Endangered Species Act. The Commission recently rejected their petition.

Perry Hergesell, DFG water policy analyst, said the pelagic organism decline is still a major concern. “The situation isn’t improving – the numbers are staying about the same,” he stated. “However, at least the numbers of delta smelt, longfin smelt, juvenile striped bass and threadfin shad didn’t drop even further.”

Jennings, whose group sued the Department of Water Resources and DFG over their failure to get a take permit for Delta smelt in the state pumps, said the pumping that took place this summer, after the state and federal governments temporarily restricted exports to protect migrating Delta smelt, is very alarming, in light of the real possibility that that we could be entering another drought year.

“It strikes me that the state and federal governments are pumping the heck out of the Delta, resulting in lower numbers of fish and their distribution further downstream,” said Jennings. “Right now it reminds me of 1976 when they pumped like mad, drawing down storage in the reservoirs, and 1977 was a disaster drought year. You would think that they would be saving some of the reservoir storage for this coming year. If we don’t get a wet year, this could be a recipe for disaster for our fisheries."