Volunteer divers from the Eel River Recovery Project counted 1,854 fall-migrating chinook salmon at six dive spots in the Eel River between Fernbridge and the mouth of the Van Duzen River on Saturday, Oct. 12.
The team also counted 15 mature steelhead and 90 "half-pound" steelhead. "Half-pounders" are steelhead less than 18 inches in length that never go far into the ocean but wait just offshore for the chinook to start up the river, then follow the chinook and eat their eggs.
A big surprise was the number of large pikeminnow present in several of the larger pools, said ERRP volunteer coordinator Pat Higgins.
Pikeminnow are predatory fish that were accidentally introduced into the Eel River from the Sacramento River in 1980s. Their predation on young salmonids and their tolerance for warm water has made them a major contributor to the decline of chinook, coho, and steelhead in the Eel River watershed.
"These fish [the pikeminnow] very likely retreated to the lower river during very low flow conditions... and seem to be enjoying their stay since temperatures hit the mid-high 60's daily and downstream juvenile steelhead likely supply a forage base," ERRP's report on the Oct. 12 dive reads.
The Oct. 12 count was the first in a series that teams from ERRP volunteers and the Humboldt Redwood Company will undertake during October and November, weather permitting.
The first count of 2013 was originally scheduled to take place on Oct.
A week later, water levels had dropped from 500 cubic feet per second to less than 200 cfs, and dive conditions were good.
Twenty volunteers took part in the Oct. 12 count, including 12 divers. Other volunteers acted as scorekeepers and helpers. Participants included staff from the U.S. Fish and Wildlife Service and the National Marines Fisheries Service, as well as fisheries consultants, members of the Yurok Tribe, and community volunteers.
Many of the divers had also participated in last year's counts. "We had a high caliber of experience," Higgins said.
Divers worked as teams, lining up in "lanes" across the width of the pool, counting only the fish that swam past them so as to avoid re-counting fish that were circling or that turned back before passing the divers. Divers standing next to each other would compare their counts, agree on a number, and shout out their results to scorekeepers on the shore.
This method does not result in an exact number, but Higgins believes the error is on the low side and that the teams are undercounting the actual number of fish.
"The order of magnitude is as important as the actual count," Higgins said. "When there's only six we'll get an exact count."
Extrapolating from all the data collected in 2012, Higgins estimated that as many as 40,000 chinook came up the Eel River last year, comparable to the record years of 1955-59.
Based on the number of salmon seen offshore and the Oct. 12 count, Higgins thinks 2013 may bring as many fish as 2012.
Considering what an unusually dry year 2013 has been, river conditions are generally very good, Higgins said. Water temperatures dropped when nights cooled off at the beginning of the month and daytime water temperatures in the lower Eel are around 64-67 degrees Fahrenheit, which is "on the high side for their enjoyment," Higgins said, but not dangerous.
ERRP is concurrently sponsoring a study of blue-green algae led by Keith Bouma-Gregson, a Ph.D. candidate in freshwater ecology from UC Berkeley, and results are expected soon. In the meantime, Higgins and the teams noticed beneficial algae, which provides a food base for fish, along the river bottom.
Teams from Humboldt Redwoods Company scheduled a dive at various places on the river between Scotia and the confluence with the South Fork at Dyerville for yesterday, Oct. 21.
Last year HRC teams counted over 2,500 adult chinook in four hours in a deep pool near Holmes.
ERRP's next dive will be held this coming Saturday, Oct. 26, beginning at 8:30 a.m. at Riverwalk in Fortuna. There will be plenty of opportunity for non-divers as well as divers to help with the fish count.
Additionally, ERRP welcomes donations. This year they are asking community supporters to pledge a penny for each salmon counted. If this year's count equals the 5,000 chinook counted by ERRP teams in 2012, the donation would total $50.
Persons feeling especially generous could pledge a nickel, dime, or quarter per fish.
PHOTOS COURTESY OF EEL RIVER RECOVERY PROJECT
1. ERRP volunteer divers gather at Fernbridge following a day of counting migrating salmon in the lower main stem Eel River. Two SoHum residents participated in this dive. Sage Halvorson of Alderpoint is standing at the far left, and Charlie Luckhart of China Creek is the tall man in the center of the group.
2. A team of volunteer divers for the Eel River Recovery Project count chinook salmon heading upstream in the main stem Eel River between Fernbridge and the mouth of the Van Duzen River on Saturday, Oct. 12.
3. ERRP volunteer diver Sage Halvorson of Alderpoint was part of the team that counted incoming chinook salmon in the lower main stem Eel River.