The ashfall caused by the eruption of Kamchatka’s Nameless volcano last month will not be able to seriously affect the beginning of the salmon dam. Only a slight delay in salmon entering the river is possible. That’s what Kamchatka scientists think.
The April eruption of the Nameless did not accidentally cause concern among the fishing community. Two years ago, the Shiveluch volcano erupted, and also a month before the outbreak of the storm. And when it was time to spawn, the fish arrived late. Hence today’s worries.
However, scientists are confident that the ashfall did not negatively affect Putin in 2023, and it will not affect him now.
Here is what the head of the Kamchatka branch of the All-Russian Research Institute of Fisheries and Oceanography (“KamchatNIRO”) says about the events two years ago Nina Shpigalskaya:
“The main ashfall as a result of the eruption of the Shiveluch volcano was observed in April 2023, when the Kamchatka River was still covered with ice. Therefore, the bulk of the ash was carried into the Kamchatka Bay during the ice drift in the river. According to the Kamchatka HYDRO specialists who monitor Pacific salmon in the Kamchatka River basin, the turbidity of the water in the river at the beginning of the spawning migration of sockeye and chinook corresponded to the normal state for this body of water, where the water is traditionally turbid due to the substrate forming the main channel of the watercourse.
Indeed, in 2023, there was a delay in the start of the spawning season for sockeye and chinook salmon by about 7 to 10 days. The most real factor in delaying approaches is the low temperature of the water in the river. In comparison with the adjacent years (2022 and 2024), in 2023, during the beginning of the spawning season of sockeye and chinook salmon (May 25 – June 10), the average temperature in the river was 7 degrees Celsius. In the same period of 2022 – 9.9 degrees, in 2024 – 11.6 degrees.
It is possible that the ashfall could have influenced the formation of the thermal regime of water in the Kamchatka River in the year under review. However, such deviations from the long-term average start dates for Pacific salmon entering a particular body of water are quite common. This is mainly due to the development of a flood situation in a particular reservoir.”
For reference. The total number of sockeye salmon from the Kamchatka River (the most widespread species of Pacific salmon in the river) in 2023 was projected at 5.2 million individuals. In fact, it amounted to 4.6 million fish. 599 thousand spawned. fish at an optimum in the range of 460 – 850 thousand fish. This was enough for the expanded reproduction of the species in the river, and the total number of the approach closely corresponded to forecasts. This once again confirms that the deposition of volcanic ash in the spring of 2023 did not negatively affect the number of salmon entering the Kamchatka River.
“We believe that, by analogy with 2023, the ashfall phenomenon will not be able to seriously affect the beginning of the 2025 harvest in certain areas, shift its timing or prevent salmon from spawning. The maximum possible effect is the effect of ashfall on the melting of snow cover in the lower reaches of the Kamchatka River. A change in the temperature regime of the water is possible, which may lead to a slight delay in the entry of Pacific salmon into the river. However, as a rule, this indicator is more dependent on climatic factors and the number of salmon producers who have returned to a particular spawning pond. As a rule, with a higher number of fish, they begin to enter the reservoir earlier,” Nina Shpigalskaya commented.
At the same time, ashfall can have a beneficial effect on fish stocks. With ash, biogenic elements enter the aquatic environment, which causes the increased development of phytoplankton, and then zooplankton, the main food of juvenile salmon. Improving the food supply increases the survival rate of juveniles and has a positive effect on the number of returns from producers. This effect is called natural fertility.
Did the ashfall of April 2023 affect the development of the salmon feeding base in Kamchatka?
“The fertilization effect (an increase in the level of nutrients) from volcanic ash, as a rule, appears in lake ecosystems. In river systems, it is practically not pronounced due to the flow of water. The plume of the main ash mass from the eruption of the Shiveluch volcano in April 2023 was directed east–northeast and fell on the catchment area of the Kamchatka River in its lower reaches and marine waters (Kamchatka Bay, Bering Sea, Pacific Ocean). At the same time, we would like to clarify that in the lower reaches of the Kamchatka River there is the largest sockeye salmon lake on the eastern coast. Azabachie. However, the lake is closed from the east by a mountain range, so there was practically no ashfall in its water area. During the spring and summer period, the resuspended ash could only periodically enter the lake with favorable wind currents.
As a result, in the fall of 2023, a cumulative effect arose from regular batch ash flows to Lake Azabachie, which led to an autumn outbreak of phytoplankton development, several orders of magnitude higher than the annual average. However, the food supply of juvenile sockeye salmon, namely planktonic crustaceans, was not affected in any way by the powerful autumn “flowering” of forage algae, since zooplankton completed development at that time. In turn, the phytoplankton cells completed their life cycle in late autumn and settled to the bottom in the form of detritus. During the winter, detritus was transformed by microorganisms into biogenic elements. But in 2024, there will be no impact of ash on the feeding base of juvenile sockeye salmon in the lake. Azabachie was not noted.”
How will the ashfall caused by the eruption of the Nameless volcano affect the food supply? Time will answer this question.
Sergey Kostrov (“The Fisherman of Kamchatka”)