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SALTON SEA TILAPIA MAKE COMEBACK -- ONS-Jim Matthews -- 17may06
Tilapia return at Salton Sea but outlook is dim for marine species
Outdoor News Service
Tilapia have made a remarkable comeback at the Salton Sea. Rangers at the state recreation area and Department of Fish and Game biologists say anglers are again filling ice chests full of tilapia. The popular gamefish weigh a half-pound up to 1 1/2-pounds, with most fish on the small end of that scale.
But the marine fish that made the Salton Sea famous -- corvina, croaker, and sargo -- are conspicuous by their continued absence.
"They are absent by any means of detection. It has been over two years without a single sighting of a single fish," said Jack Crayon, a DFG associate fishery biologist working on the Salton Sea Program from Bermuda Dunes.
Since the spring of 2002 when fish population crashed at the Salton Sea, the DFG has been doing quarterly gill net samples, with the most recent effort just two weeks ago, according to Crayon. The samplings represent over 6,400 net hours of effort (a net hour equals a six-foot high, 150-foot long net in the water for one hour), and not a single corvina, croaker, or sargo has been caught in these nets since 2003. There has also not been a single report of an angler-caught fish, and Crayon said they have not found one of these once-popular gamefish when combing through thousands of fish that have washed up on shore during annual dieoffs caused by oxygen depletion.
"They're not out there hiding someplace," said Crayon. "As a fishery biologist, after three years of surveys, I don't expect a return of the marina species until we begin restoration of the Salton Sea -- and at that point, we'll probably have to restock them."
Biologists have been predicting the death of the fishery at the Salton Sea since the early 1970s because of rising salinity levels, but each time the sea was seemingly on its last gasp, there would be a miracle of nature in the form of El Nino rains that brought a much-needed flush of fresh water to the salty lake. For more than three decades, the marine species dodged the salinity bullet.
Ironically, Crayon said the death knell for the corvina, croaker and sargo turned out not to be salinity. "We lost the marine species at a lower [salinity] level than we thought we would. We underestimated the impact of nutrient levels. It turns out water quality kind of trumped salinity as the grim reaper," said Crayon.
Unlike tilapia, all of the marine species are open-water spawners and feeders, and the high and growing nutrient load in the sea depletes oxygen levels over vast areas, making nearly the entire Salton Sea an anaerobic system at times during the hot summer months. This caused an almost total fish dieoff. Small numbers of tilapia survived near shore where constant wave action keeps the water oxygenated, but few if any of the other species survived.
Many long-time anglers want to believe that the current boom of tilapia numbers will be followed by corvina and croaker comebacks. It's happened this way before. An avid angler, Crayon doesn't want to be this messenger of gloom, but he says "don't hold your breath." While the DFG's sampling wasn't near as extensive in the past, previous dieoffs were never so dramatic. A few corvina and croaker were always present. Until now.
"You can't argue with a gill net," said Crayon. "We lost all marine sportfish."
But the good news is that the tilapia are recovering, booming even. Crayon said this is the strongest spring for tilapia numbers since the DFG began extensive quarterly surveys in 2002, and while the DFG estimates there's probably only about 10 percent of the tilapia biomass in the Salton Sea as there was in the 1990s, the areas with fish have lots of them.
A state park ranger reported this week that one group of anglers had filled up both of their 100-quart ice chests with tilapia in less than two hours of fishing.
The action has been restricted to the northeast side of the Salton Sea at the state recreation area. The south end and west shorelines have not had a significant number of tilapia, unlike past boom years when tilapia could be caught everywhere around the sea. Most anglers are fishing for the tilapia with a simple rig consisting of a bell sinker at the end of the line and two hooks on dropper loops above the sinker. The hooks are baited with pieces of nightcrawler, and the action is almost non-stop with anglers often able to land two fish at a time while watching hoards of spawning fish from shore.
A Salton Sea environmental recovery document is being drafted now. It will have at least 10 alternatives and should be available for public review later this summer. Crayon said the eight "action" alternatives all call for a reduction in the size of the Salton Sea.
"There's just not enough water out there to have your father's Salton Sea any more," said Crayon. The question that won't be answered for some time is whether or not the Salton Sea will ever resemble the incredible marine fishery it was for at least two generations of Southern California anglers.
Tilapia return at Salton Sea but outlook is dim for marine species
Outdoor News Service
Tilapia have made a remarkable comeback at the Salton Sea. Rangers at the state recreation area and Department of Fish and Game biologists say anglers are again filling ice chests full of tilapia. The popular gamefish weigh a half-pound up to 1 1/2-pounds, with most fish on the small end of that scale.
But the marine fish that made the Salton Sea famous -- corvina, croaker, and sargo -- are conspicuous by their continued absence.
"They are absent by any means of detection. It has been over two years without a single sighting of a single fish," said Jack Crayon, a DFG associate fishery biologist working on the Salton Sea Program from Bermuda Dunes.
Since the spring of 2002 when fish population crashed at the Salton Sea, the DFG has been doing quarterly gill net samples, with the most recent effort just two weeks ago, according to Crayon. The samplings represent over 6,400 net hours of effort (a net hour equals a six-foot high, 150-foot long net in the water for one hour), and not a single corvina, croaker, or sargo has been caught in these nets since 2003. There has also not been a single report of an angler-caught fish, and Crayon said they have not found one of these once-popular gamefish when combing through thousands of fish that have washed up on shore during annual dieoffs caused by oxygen depletion.
"They're not out there hiding someplace," said Crayon. "As a fishery biologist, after three years of surveys, I don't expect a return of the marina species until we begin restoration of the Salton Sea -- and at that point, we'll probably have to restock them."
Biologists have been predicting the death of the fishery at the Salton Sea since the early 1970s because of rising salinity levels, but each time the sea was seemingly on its last gasp, there would be a miracle of nature in the form of El Nino rains that brought a much-needed flush of fresh water to the salty lake. For more than three decades, the marine species dodged the salinity bullet.
Ironically, Crayon said the death knell for the corvina, croaker and sargo turned out not to be salinity. "We lost the marine species at a lower [salinity] level than we thought we would. We underestimated the impact of nutrient levels. It turns out water quality kind of trumped salinity as the grim reaper," said Crayon.
Unlike tilapia, all of the marine species are open-water spawners and feeders, and the high and growing nutrient load in the sea depletes oxygen levels over vast areas, making nearly the entire Salton Sea an anaerobic system at times during the hot summer months. This caused an almost total fish dieoff. Small numbers of tilapia survived near shore where constant wave action keeps the water oxygenated, but few if any of the other species survived.
Many long-time anglers want to believe that the current boom of tilapia numbers will be followed by corvina and croaker comebacks. It's happened this way before. An avid angler, Crayon doesn't want to be this messenger of gloom, but he says "don't hold your breath." While the DFG's sampling wasn't near as extensive in the past, previous dieoffs were never so dramatic. A few corvina and croaker were always present. Until now.
"You can't argue with a gill net," said Crayon. "We lost all marine sportfish."
But the good news is that the tilapia are recovering, booming even. Crayon said this is the strongest spring for tilapia numbers since the DFG began extensive quarterly surveys in 2002, and while the DFG estimates there's probably only about 10 percent of the tilapia biomass in the Salton Sea as there was in the 1990s, the areas with fish have lots of them.
A state park ranger reported this week that one group of anglers had filled up both of their 100-quart ice chests with tilapia in less than two hours of fishing.
The action has been restricted to the northeast side of the Salton Sea at the state recreation area. The south end and west shorelines have not had a significant number of tilapia, unlike past boom years when tilapia could be caught everywhere around the sea. Most anglers are fishing for the tilapia with a simple rig consisting of a bell sinker at the end of the line and two hooks on dropper loops above the sinker. The hooks are baited with pieces of nightcrawler, and the action is almost non-stop with anglers often able to land two fish at a time while watching hoards of spawning fish from shore.
A Salton Sea environmental recovery document is being drafted now. It will have at least 10 alternatives and should be available for public review later this summer. Crayon said the eight "action" alternatives all call for a reduction in the size of the Salton Sea.
"There's just not enough water out there to have your father's Salton Sea any more," said Crayon. The question that won't be answered for some time is whether or not the Salton Sea will ever resemble the incredible marine fishery it was for at least two generations of Southern California anglers.
