Managing the Anchor River’s king salmon runs for the past few years has taken a little strategy.

The Anchor River, an anadromous stream system near Homer, is a location many fishermen seeking king salmon on the Kenai Peninsula head for the season opener. The king salmon run starts in May and peaks in early June, earlier than the runs in more fished-over rivers like the Kasilof and the Kenai. It’s also one of only three fresh water bodies besides the Kasilof and the Kenai rivers that are open to king salmon fishing.

However, the salmon runs there have pitched from the low to the high ends of the sustainable escapement goals in the river for the last few years. The Alaska Department of Fish and Game maintains a goal for king salmon of between 3,800 and 10,000 fish for the Anchor River. Last year, the total run for the season topped the escapement goal at 10,046, said Carol Kerkvliet, the area Fish and Game biologist based in Homer.

In years before, the count was significantly lower. In 2014, the total count by Aug. 3 was 2,496; in 2013, the total was 4,391. Those two years were the lowest, and the river hovered near 5,000 fish before that, Kerkvliet said. But the fishery had been taking a slow dive since 2009, she said.

“In 2009 and 2010, it was a period of poor production, frankly, and we restricted the fishery in-season,” Kerkvliet said. “We were a little more aggressive in 2010. We also wrapped (the) Deep Creek and Ninilchik (rivers) in with those restrictions, and also the marine fishery, because of the ballooning effect. But even in 2010, we didn’t make our goal.”

The Anchor River is relatively new to comprehensive escapement counts. Prior to 2003, all the counts were done by aerial survey in late July or August, after the fishing season was complete. The department began conducting a full count in 2003, which allowed them to establish an escapement goal.

Before that, the Board of Fisheries had listed the Anchor River chinook salmon as a “stock of management concern” and made the restrictions on the river more conservative, Kerkvliet said. When the department presented the numbers in 2004, the board rescinded the listing.

For a few years, the Anchor River kept a steady production. But in 2010, the production began to drop.

By 2014, the run was so small that even with the harvest, Fish and Game wouldn’t have met its escapement goal, Kerkvliet said.

But then in 2015, the number of fish more than tripled. In previous years, some of it was production issues or possibly hazards in the marine environment, but the data is still so recent that Fish and Game is working on analyzing future runs.

“Preseason forecasts, they are still difficult for the Anchor River,” Kerkvliet said. “We’re just getting full returns from 2010. That’s not a lot (of years). And during those years, production was very low. For each year, the return from the spawning event, that gives us more information.”

Some have cited rising water temperatures as a risk to the salmon. The temperatures in the river and streams regularly exceed the state’s regulations for salmon spawning waters of 15 degrees Celsius, or 59 degrees Fahrenheit.

The average temperature, even in the summer, remains below the standard, but from 2008–2012, the watershed temperature exceeded 15 degrees Celsius on 18 days per year, according to a water temperature analysis produced by Cook Inletkeeper.

Higher temperatures stress juvenile and spawning salmon, possibly reducing the number of young salmon that can be raised in the watershed. The precise effect of rising water temperature on salmon is not known, but Cook Inletkeeper has been monitoring the water temperature since 2002, said Sue Mauger, the science director for the organization.

The organization, which focuses on environmental conservation in the Cook Inlet area, runs a real-time data stream reporting the temperature in the Anchor River watershed. Workers take readings all year long and monitor them for any possible changes. The river’s temperature is beginning to flatline for the season, which is normal, she said.

The Anchor River is largely fed by snowpack, which made this year a warmer year because there was so little snow on the Kenai Peninsula last winter. Compared to rivers that are fed by groundwater, rivers that depend on snowpack are more likely to be influenced by heating from the sun because groundwater is consistently cold.

For example, Funny River is fed by groundwater and is not very influenced by UV radiation, but Quartz Creek, Resurrection Creek and Anchor River are, Mauger said.

“Some systems have more sensitivity than others, and the Anchor River is a sensitive system,” Mauger said. “This summer, we also had really low water levels. A little bit of water tends to warm up a lot faster than a lot of water.”

Mauger said Cook Inletkeeper is in the process of applying to conduct a retrospective study on the various chinook-bearing streams in the Cook Inlet area. Though it has not officially started yet, the organization aims to look at 30 years of data and examine how the salmon return to the stream systems and how fishery managers can better understand the salmon’s life patterns.

“Every river has sort of a different pattern or dominant life history of chinook,” Mauger said. “We do need to understand whether we are seeing an impact. The fisheries managers need to take that into consideration.”

Reach Elizabeth Earl at elizabeth.earl@peninsulaclarion.com.