Carp + Wind
Carp and their destruction of Malheur Lake and Blitzen River vegetation continues and with that, the work to manage their population is ongoing.
Trapping Carp. Just up from Malheur Lake, on the refuge, is a fish trap along the Blitzen River. This trap is checked daily for carp and all carp captured are prevented from entering the Blitzen and mixing with the redband trout and other native fish. The fish collected in this trap are measured and weighed to determine an accurate length to weight ratio for carp that is site specific to Malheur Lake. Some additional testing is done as well to help in determining which management actions may be most effective in reducing carp numbers.
Malheur Lake Restoration. Twice a week on Malheur Lake, from the seat of an airboat, 8-12 locations are tested for water quality and light profile readings (how far light can penetrate into the lake). The data collected from these tests helps with understanding how light varies with turbidity (unclear water conditions caused by stirred up sediment), what types of suspended material contribute to turbidity, and what factors control the concentration of suspended material. This collected data will guide decisions about how to best restore Malheur Lake.
The abundance of carp over the years in Malheur Lake has devastated the lake's vegetation and caused sediment to remain suspended in the water. But there has been a reduction in the carp thanks to the use of commercial fishing. Commercial fisherman catch the carp which are processed into an organic fertilizer to be used in organic farming.
Despite what appears to be a reduction in the carp population, when you're out on the lake rather than seeing vegetation and the bottom of the lake, you see brown, murky water and pelicans, lots of pelicans, that feed on the carp. Due to a lack of vegetation many other bird species do not visit the lake in favor of other locations that have the food sources they need. Add to this wind. When wind moves across 7 mile wide Malheur Lake, waves rise which translates into swirls of water underneath the surface that stir up the sediment not grounded in place by vegetation, creating the brown, murky water. These turbid water conditions prevent light from reaching the lake bottom and allowing vegetation that provide bird habitat to regrow.
With this information and more, the Malheur Lake Working Group is meeting regularly to decide how to best move forward with Malheur Lake restoration.
How you can help . . . come fishing! The annual Carp Derby at Malheur Refuge is Saturday, August 18. Learn more.