Posts Tagged ‘salmon’

by Eric Ettlinger

Another week without rain and very few salmon are spawning in Lagunitas Creek. MMWD biologists documented 24 coho salmon and seven new coho redds this past week. We also saw three Chinook salmon and identified what appeared to be five new Chinook redds. The total counts are similar to what we saw the week before, but far below average for the third week of December, which should be peak spawning time. In fact, excluding the population crash of 2008-09, the 22 coho redds seen so far this season are the fewest seen for this date in the last 17 years. Back in 2004-05, the great-grandparents of this year’s coho had constructed nearly 200 redds by this date (see chart).

Looking on the bright side, Lagunitas Creek is faring better than many coastal streams that continue to be closed by sand bars due to the record-breaking dry spell we’re experiencing. Water releases by MMWD have allowed some salmon to migrate as far upstream as Peters Dam, and more water will be released in January to facilitate additional spawning. In about a third of years, coho spawning peaks in January and this appears to be one of those years. All we can do is hope that rain returns soon.

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by Eric Ettlinger

Coho salmon are currently spawning throughout Lagunitas Creek, albeit in below-average numbers. We observed 21 coho salmon and 11 new redds this week (see table of MMWD salmonid observations so far this season). The most upstream of these fish were two coho on a redd upstream of the Leo T. Cronin Fish Viewing Area, about as far upstream as salmon can go in the creek. These fish likely migrated upstream following the small storm we received last week. We expect coho spawning activity to increase slowly but remain below average while the dry weather continues.

Chinook salmon observations have declined over the last few weeks, with only one Chinook and one Chinook redd observed this week. We may see another pulse of Chinook if/when the rain returns. The extended weather forecast is for dry conditions to continue for the next two weeks.

coho redd

Coho redd

I’ve included a photo of one of the coho redds we observed this week. The contrast between the light-colored redd and the dark, undisturbed streambed, plus the extraordinarily clear water, make this redd unusually easy to identify. Upwards of 2,000 salmon eggs are likely buried in the upper right portion of this redd.

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Photo 1 of work partyby Erin Tracy, Watershed Stewards Project Member

The Americorps California Conservation Corps Watershed Stewards Project in partnership with Marin Municipal Water District hosted a volunteer Lagunitas Creek habitat enhancement on Saturday, November 23,  and it was a huge success!  Following a large woody debris installation to improve coho salmon habitat in the creek, the disturbed bank was in need of some rehabilitation.  Thirty motivated volunteers spent their Saturday planting the creek bank with native trees, shrubs and ground covers.  Re-vegetating this bank will not only reduce erosion and excess sediment flow into the creek but will also provide shade and cooler water temperatures that salmon need to thrive.

The day started at the Leo T. Cronin Fish Viewing Area parking lot, where volunteers could read interpretive signs about spawning salmon and try to catch a glimpse of one in the creek while waiting for everyone to arrive.  Sipping hot chocolate and tea, we huddled together in the cold morning to talk about our goals for the event.

Photo 2 - planting shrubWith the volunteers, we made our way down to the site and went straight to work planting the potted plants and transplanting sword fern, redwood sorrel, blackberry, and thimbleberry.  At lunch we gathered around the newly installed large woody debris structures and listened to Eric Ettlinger, an aquatic ecologist for MMWD, talk about the role of woody debris as winter habitat for salmon.  Lastly, volunteers helped with trash clean up and brought in woody debris to block off footpaths down to the creek to ensure their planting efforts would remain undisturbed.

At the end of the day a total of 48 plants had transformed the formally barren creek side.  It was an incredibly successful day and we are so thankful our volunteers came out to help the watershed.  We look forward to watching the progress of the plants and seeing this bank returned to the healthy ecosystem it once was.

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by Rosa Albanese, Watershed Stewards Project Member

This is the last in a year-long series celebrating the 40th anniversary of the Endangered Species Act.

Photo of steelhead trout

Steelhead trout in Lagunitas Creek. Photo by MMWD Aquatic Ecologist Eric Ettlinger.

What better way to end this series than with the enigmatic Oncorhynchus mykiss of the salmonidae family. This species exhibits more survival strategies than any other Pacific salmonid species, including flexible habitat preferences, differences in reproductive biology and adaptability in their life cycle types between generations.  Step into any body of fresh water and the fish you would mostly likely encounter is O. mykiss. However, they are still faced with many of the same threats as other salmon and must be carefully managed to ensure their future success.

When referring to O. mykiss one may be talking about rainbow or steelhead trout. What’s the difference? If they never migrate, they are considered rainbow trout. But if they make the great migration to the ocean and back, they are known as steelhead. However, although rare, it has been reported that the offspring of a steelhead may grow up to be a resident rainbow trout and vice versa.  But, basically, steelhead are anadromous (migratory) rainbow trout.

Steelhead also vary in when they migrate. Steelhead have two principal life history patterns: summer and winter runs. Summer steelhead enter streams as immature fish during the receding spring flows and  spend the summer holding up in deep pools, typically near a stream’s headwaters, where they then mature to spawn in winter or spring. Lagunitas Creek, which originates on Mt. Tamalpais and flows west to Tomales Bay, is home to winter-run steelhead. These fish are similar to coho salmon in that they enter the streams from the ocean during winter rains as mature fish. However, steelhead generally spawn later than coho, between January and April. Also, unlike all other salmonid species, they may spawn more than once throughout their lives, which is referred to as iteoparity.

Regardless of life history path, for the first year or two of life steelhead/rainbow trout can be found in cool, clear and fast-moving streams with ample cover and diverse and abundant invertebrate life.  Although highly variable in color and size, adults can generally be identified as a silvery trout with black spots covering their back, dorsal fins and tail and a reddish band along their sides. They can grow to be 45 inches long and weigh close to 50 pounds, but in Lagunitas Creek adult steelhead are typically closer to 30 inches long. These fish have adapted a streamlined body shape that helps them hold their position and swim in fast-moving water, which may be why they are considered by many anglers to put up a good fight and are so highly sought for sport.

Within California, native populations of coastal steelhead have experienced declines similar to those of other local salmonid species. The reasons are complicated but are largely due to competition with humans for habitat, dams and other alterations of landscapes, overfishing and introduction of foreign species as predators and competitors. Due to their diverse life history, management of steelhead is somewhat complicated. Steelhead stocks are placed into groups based on broad geographic distributions, plus run-timing, and many local populations are granted different taxonomic classification. For example, here in Marin County steelhead are classified as part of a Central California population and are federally listed as threatened, while populations further south are listed as endangered. Regardless of the terminology, steelhead are at risk.

There are many important reasons to protect such a unique fish species. Not only are they indicators of stream health, but preserving their wonderfully complicated diversity will allow them to adapt to changing environmental conditions. Steps to the recovery of steelhead and other salmonids start with support for projects that restore watersheds, ensure sustainable stream flows, reduce migratory barriers and minimize competition from non-native species. Protecting California steelhead and other andromous fish ensures that our fresh water and ocean habitats remain intact for future generations and a remarkably diverse species continues to adapt and thrive.

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Photo of Chinook salmon in Lagunitas Creek

Chinook salmon in Lagunitas Creek. Photo by Madeline Cooper, a member of the Watershed Stewards project.

by Eric Ettlinger

Salmon spawning season has returned to Lagunitas Creek, and so has one of its more sporadic and uncommon visitors. Chinook salmon, commonly known as king salmon, have been seen spawning in the creek for the first time in five years! The first sign of Chinook this season was a redd discovered on October 24, which would be exceptionally early for our resident coho salmon to spawn (a redd is a gravel nest where salmon lay their eggs). Their presence was confirmed on November 13 when three Chinook spawners were seen on that very same redd. Since then MMWD biologists have documented a total of seven Chinook salmon in Lagunitas Creek, which is the most seen since 2006. These salmon probably weren’t born in Lagunitas Creek but may have gotten lost as they tried to migrate back to their natal streams in the Central Valley.

One of the most perplexing aspects of our Chinook observations this season has been the presence of very small salmon (less than a foot long) sharing redds with very large Chinook. These small fish behave like “jacks,” which are small but sexually mature salmon that return to spawn a year earlier than full-sized salmon. The adult male salmon chase the jacks like they were competitors, but we’ve never seen jacks this small. We’ve only seen two so far, but ruled out trout or other fish species as candidates. A little research turned up a Chinook life history variant called the “mini-jack,” which migrate as fry to estuaries for only a couple of months before swimming back upstream to spawn. If these little fish are indeed mini-jacks, then Chinook salmon must have spawned in Lagunitas Creek last year without being observed. We did find a few redds in October and November last year that looked like Chinook redds, but without seeing the fish we couldn’t assume that Chinook had returned. Now it looks like the King may have returned a year ago.

To date we haven’t seen any coho salmon in Lagunitas Creek, but that’s not unusual. The first coho tend to show up in late November after heavy rains increase stream flows. Last week’s rain hardly increased flows, so the coho may be waiting a little longer to migrate upstream. Rain or no rain, we’ll probably start seeing coho within the next couple of weeks. Once the rain really starts falling, we’re expecting more coho salmon to return to Lagunitas Creek than we’ve seen in at least seven years.

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by Eric Ettlinger

Long before sub-prime mortgages became a household term, coho salmon were suffering through their own housing crisis. For more than a century, dam construction has blocked salmon from returning to the birthplaces of their ancestors. In Marin County, dams and urbanization have eliminated most of the habitat for salmon, and much of the remaining habitat is highly degraded. Some of the best remaining habitat is in Lagunitas Creek, which runs through Water District, State Park, and federal land. But even here the creek bears the scars of logging, hydrologic manipulation, and land management practices that included removing logs from the channel. These logs, which once included massive old-growth redwoods that could remain stable for decades, provided deep water, protection from predators, refuge from floods, and even insects for food. Without these log houses, young salmon are essentially living on the streets, vulnerable to predators, the weather, and hunger.

woody debris structures Lagunitas Creek

Log structures constructed in Lagunitas Creek in 2013

Starting in 1999, the Marin Municipal Water District began collecting logs from Kent Lake and using them to build log structures for juvenile coho salmon. The first structures were fairly simple: one to three cut logs, held in place with boulders and cables, and often protruding a short distance into the creek. Over time we learned that structures that collect sticks and small logs also tend to create the deepest pools with the most fish. We now build larger, more elaborate structures and arrange them in groups to transform simple, straight channels into complex meanders. In September, using funding provided by the California Department of Fish and Wildlife, we completed four new structures in a straight, shallow section of Lagunitas Creek. By next summer the creek will hopefully be meandering between complex debris jams housing hundreds of juvenile coho salmon.

snorkeling salmon survey

MMWD’s AmeriCorps interns counting juvenile salmon

So how do we know that these log homes are actually benefitting salmon? We monitor them extensively, measuring water depths, observing them during winter storms, and snorkeling around them to count the juvenile salmon using them through the summer. The results have been encouraging. Coho numbers at enhancement sites quadrupled within two years of construction. In the last 15 years the summer survival rate of juvenile coho throughout Lagunitas Creek has increased by approximately six times. While we can’t prove that the log structures are responsible for the increase in coho survival, the evidence suggests that providing more homes has made Lagunitas Creek a safer neighborhood for coho salmon.

large woody debris vs salmon survival

Summer survival of juvenile coho has increased as more log structures have been built. The New Year’s Eve Flood of 2005 took a toll on both structures and salmon. (Click chart to view.)

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by Erin Tracy

This post is the tenth in a year-long series celebrating the 40th anniversary of the Endangered Species Act. Read the previous post here.

Coho salmon spawning season is almost upon us again, so if you want to see one of California’s most spectacular endangered fish in action, late November and December are the times to do it.

Starting in the late fall, coho begin their long journey from their two-year homes in the ocean back to the river of their birth. This is an incredibly strenuous and at times dangerous journey that every coho embarks on with the hopes of successfully reproducing, even though they meet an untimely end within a few weeks of spawning. Sense of smell is the key factor in the salmons’ travels from their distant ocean homes to their natal river. Salmon have a keener sense of smell than dogs, and in combination with ocean currents and the gravitational pull of the moon, they are able to make their way back to the river of their origin to start the whole process over again.

Spawning season is brought on by heavy rains that open up the waterways by breaching sand bars and providing the right amount of water depth and flow for the salmon to swim upstream. Once female salmon have made it upstream, they begin to build nests (called redds) near the heads of riffles where the water just begins to flow rapidly. This water flow allows for plenty of dissolved oxygen to reach the eggs and aids in growth.

Salmon redd

Salmon redds are relatively easy to identify in clear streams because the large pit and gravel mound are lighter in color than the surrounding streambed.

To create these impressive nests the female fish must flip her body up and down to dig out a gravel pit and lay her eggs inside. Female coho can lay up to 2,600 eggs and, depending on the size of the fish, these pits can stretch the width of the stream. Once the eggs are deposited into the redd, one or two males will fertilize them, and then the female will immediately cover the eggs with gravel. She will protect this redd for as long as she can until she dies.

Although Lagunitas Creek supports one of the largest and most stable coho populations south of Mendocino County’s Noyo River, coho are found in fewer than half of the streams they once inhabited. Since coho numbers are still low enough to land them on the endangered species list, it is vital that we do everything we can during spawning season to ensure the health of the species. Here are a few simple things you can do during spawning season to help:

  • Don’t go fishing! Fishing is prohibited in Lagunitas Creek. (You can, however, fish in MMWD’s reservoirs. Call 415-945-1194 for current information.)
  • Cross streams only at established crossings.
  • Keep pets out of the creek.
  • Don’t remove woody materials from stream channels.
  • When observing salmon, minimize noise and avoid sudden movements so that the fish may spawn undisturbed.

If you want to see these fish in action, go two to three days after a heavy rainstorm to MMWD’s Leo T. Cronin Fish Viewing Area in West Marin (find directions on our website).

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