Tens of tons of tilapia in the floating cages of the Tamiyang River, in Awang Bangkal Village, Karang Intan District, Banjar Regency, South Kalimantan (South Kalimantan) died suddenly. The death of tens of tons of tilapia has occurred since the last three days. Even though the fish will be harvested in a month. One of the tilapia fish farmers in Awang Bangkal Village, Mahmudah said, did not know the cause of the death of the tilapia in his pond.
Courtesy of regional.kompas.com
The sun beat down relentlessly on Bristol Bay this summer, heating up the rivers and lakes where millions of sockeye salmon returned to spawn. July was the region’s hottest month on record, and in some rivers, that heat was lethal.
Tim Sands, a biologist for the Alaska Department of Fish and Game, estimates tens of thousands of fish died.
“Based on the catch rates we normally see and the escapement we normally see, well over 100,000 fish died in the river,” Sands said.
He’s talking about the Igushik River on the west side of Bristol Bay. It’s a long, winding, muddy river in the Nushagak District.
By early July, biologists were expecting an average of 15,000 fish to swim upriver every day.
Instead, “We saw 714 fish go up the Igushik by the tower on July 8,” Sands said. “The lack of fish moving up the Igushik River definitely was abnormal.”
Salmon won’t swim through water once it reaches a certain temperature. Water loses oxygen as it gets warmer, and the warmer it gets, the more oxygen fish need. As fish crowd on the bottom of a river waiting for the water to cool, they have less and less oxygen to breath.
Sands said about half a million fish should have escaped upriver to spawn. They only counted half that.
“The difference could have been all dead fish. That’s why I’m saying at least 100,000, ’cause truthfully I believe it could well have been over 200,000 fish. Cause that’s what we’re missing from the escapement,” he said.
Bristol Bay did have a huge harvest this summer — the second-largest on record. So when the heat broke toward the end of July and the fish pushed upriver, Igushik fishermen were actually able to catch more fish than usual. But that didn’t translate to a great season for everyone.
Courtesy of ktoo.org