Monterey Bay Salmon & Trout Project

Where Did All the Salmon Go?
(And What About Steelhead?)

As most of you know by now- the Pacific Fisheries Management Council will recommend to the Secretary of Commerce that salmon fishing season be closed this year. Less than half of the minimum number of Chinook needed for successful spawning is expected to return to the Sacramento River this year. Needless to say this was a stunning blow for many, and most people are still wondering why. The simplest answer appears to be that when juvenile Chinook and Coho salmon went to sea during the springs of 2005 and 2006, there simply was not enough food. Due to unusual oceanographic conditions, there was a breakdown in the food web that juvenile salmon depend on when they first enter the sea, resulting in two things: a lot of hungry juvenile salmon swimming around in clear water and a lot of hungrier predators.

Below is a technical report that our research team produced at the NOAA Southwest Fisheries Center in case you are interested in the specific details. Several questions probably occur to many of you: Will this happen again? Can salmon stocks recover if the ocean goes back to normal? And, what about Steelhead? Taking these in order, the answer to the question of will this happen again is unclear. The reasons ocean conditions were poor in 2005 and 2006 were slightly different between the two years but the net result was the same, poor food supply. Obviously if this can happen two years in a row, it can happen again.

The collection of the necessary oceanographic data take some time and we are not yet able to determine if 2007 had similar issues or not. In the report below, we describe what physically changed in the ocean to cause this food supply shortage, however it will probably be some time (10+years) before oceanographers have a sense of WHY the changes occurred. This could be an early sign of potential climate change, or it could be a “blip” that might not repeat itself for decades. Can salmon stocks recover?

As most of the returning Coho salmon in Scott Creek were actually “jack” males (2-year olds) that would normally have returned as adults in January 2009, it was a good sign that things might be better for Coho next year. As Coho spend less time at sea, at least one of the three year classes may not have encountered these poor oceanographic conditions. Thankfully, working with MBSTP a captive broodstock program was started for Coho salmon in 2002 and there were captive fish for spawning at the hatchery to help prevent the total loss of this year class.

Chinook spend a longer time at sea however and many of the year classes (fish that went to sea in 2004, 2005 and 2006) may have been impacted by this shortfall in food. It is too early to tell how long recovery will take, but one can be optimistic that between the hatchery production available in California and the potential for a few good years of ocean conditions, stocks could recover, hopefully quickly. "It is too early to tell how long recovery will take, but…stocks could recover, hopefully quickly."

Following El Niño events, which can reduce returning adult numbers because of poor ocean conditions, the Central Valley Chinook stocks rebounded in 2-3 years. And, what about Steelhead? Stories are flowing back and forth- “fishing was bad this year in Santa Cruz…”, “the Trinity had record returns…”, “big fish in the San Lorenzo…” The general sense from talking to fisheries biologists up and down the coast was that Steelhead had an okay, possibly better than average year this year.

Locally, we run the fish trap in Scott Creek. While the final counts are not in yet, it looks like we had our strongest return in 3 years. However, aside from a big storm in early January, which was a little early for most Steelhead, there was little rain and we saw very few fish until that big storm in early February. It looks like fish had probably been arriving, but were stalled from getting into the river until that storm.

In Scott Creek, when that storm happened, about 75% of the whole run came in during the 2 days of high flows, swimming right through the fishing area up into the spawning habitat. We don’t have a lot of data, but it’s possible a similar thing happened on the San Lorenzo River. So why were there good Steelhead returns, while salmon runs were poor? The answer probably lies with two major differences.

When juvenile Chinook and Coho go to sea, they are typically 3” and 4-5” in length respectively. They rely on being able to eat as soon as they go to sea and growing fast enough to avoid predators. Obviously the bigger a fish is, the fewer number of mouths it can fit in and the faster it can escape. Steelhead typically go to sea between 6-8” in length, giving them a real advantage in avoiding predation. So even if Steelhead went to sea larger, why didn’t they starve if there was no food in the ocean? There is a reason for Steelhead going to sea at larger sizes. Those of you who fish for salmon in Monterey Bay and along the coast may know that you catch Chinook and in good years Coho.

But most never catch Steelhead. We know that local Chinook and Coho stocks spend most of their marine lives on the coastal shelf of California and Oregon, using an oceanographic feature known as the California Current. However the best (but limited) data we have is that most Steelhead do not do this. Instead these “trout” probably have a very long migration when they enter the ocean, where they head much farther north and potentially farther out to sea. Most Steelhead that have been caught in the ocean are found in an area roughly between Southeast Alaska and Northern Japan. We have data suggesting that even our local Santa Cruz fish go there. This is obviously pretty far from California and we suspect that the ocean conditions that had such a negative local effect on salmon were just that – local, and that Steelhead forage in a different part of the ocean that was not affected.

Hopefully that provides some information for people. Obviously we still have much to learn and we are working as fast as we can. For those of you who are interested in more technical details, I have included the following report.

"…we suspect that the ocean conditions that had such a negative local effect on salmon were just that – local, and that Steelhead forage in a different part of the ocean that was not affected."

Coho and Chinook salmon Decline in California during the spawning seasons of 2007/08 Prepared by R.B. MacFarlane, S. Hayes, B. Wells 2 February 2008 The short version Near final data from across the range of Coho salmon on the coast of California reveal there was a 73% decline in returning adults in 2007/08 compared to the same cohort in 2004/05. The problem extends beyond California: preliminary data from the Oregon coast show a 70% decline.

The low Coho salmon numbers come on the heels of the Pacific Management Council’s report of exceptionally low Chinook salmon returns to California’s Central Valley (and other streams in California, Oregon, Washington, and British Columbia) in the fall of 2007. Because of the broad spatial extent of the decline and the similar ocean ecology of the two species, ocean conditions are suspected as a main causative agent. The Wells Ocean Productivity Index (WOPI), an accurate measure of central California ocean productivity, reveals poor conditions during the spring and summer of 2006, when juvenile Coho from the 2004/05 spawn entered the ocean. The WOPI also showed low productivity potential for the spring and summer of 2005, which may explain low returning Chinook salmon numbers in 2007.

Further, if the WOPI has predictive power, adult Chinook salmon returns in 2008 should be low. The long version The Pacific Fisheries Management Council (PFMC) reported on 29 January 2008 unexpectedly low Chinook salmon returns to California in 2007, in particular to the Central Valley. Adult returns to the Sacramento River, the largest of Central Valley Chinook salmon runs, failed to meet resource management goals (122,000-180,000 spawners) for the first time in 15 years. Now preliminary reports near the end of the 2007/08 spawning run indicate Coho salmon are experiencing poor returns as well. As Coho spawning season is nearing an end in California, state and federal biologists, using a variety of techniques, including visual, video, spawner/carcass, and redd surveys have found Coho salmon returns to be far below what was expected, based on returns three years earlier, which are the same populations or yearclass lineages.

Coho salmon are listed as endangered and threatened in the Central California Coast and Southern Oregon-Northern California Evolutionarily Significant Units (ESU), respectively, under the U. S. Endangered Species Act (ESA). Coho have essentially a fixed three- year life cycle in California, in contrast to Chinook salmon, which may return as mature adults as three (primarily), four, and some five year olds. For Coho, each yearclass can be considered essentially a separate population because there is little mixing among yearclass lineages, with the exception of “jacks” that return as 2-year old males in limited numbers. In California, mature Coho salmon return to natal streams between late November and late January into February in coastal streams between irrigation, and water exports from streams, the spatial extent of the problem points toward a broader agent: ocean conditions. It is known that the first few months in the ocean are a critical period for growth and survival in salmonids.

Recent work in the Fisheries Ecology Division shows that the greatest rates of growth and energy accumulation for Chinook salmon occurs in the first one to three months after ocean entry. Chinook salmon in California enter the ocean as subyearling and at a smaller size than Coho, which enter the sea as yearlings after about 1.5 years in freshwater. Thus, Chinook and Coho hatched in the same year, enter the ocean one year apart. Both enter in late spring to early summer, theoretically driven by evolutionary adaptation to seasonally beneficial feeding and growth conditions from a suite of climate and oceanographic factors that result annually in high biological productivity on the California coast between spring and late fall. Ocean conditions were poor for salmon growth the Oregon border and Scott Creek in Santa Cruz County. They return earlier in the northern part of the state grading to mid-December to mid- February in Scott Creek.

In recent years, returns to Scott Creek were essentially complete by the end of January. Typically, spawning occurs within a month or so after stream entry, whereas at the southern end of the range, it occurs almost immediately. Juvenile salmon emerge from redds in late winter – early spring and spend one year in the stream before migrating to the ocean in the following spring. They spend about 1.5 years in the ocean and return to spawn in the late fall-early winter three years hence. Coho salmon returns in 2007/08 Of 13 streams between the Smith River and Scott Creek where surveys are conducted, there has been a 73% decline in returning Coho salmon, compared to the same yearclass lineage returns in 2004/05 (Fig. 1). No stream had an increase or level returns. One stream, Redwood Creek in Marin County had a complete failure, with no returns for the first time on record. Scott Creek had only nine fish return, compared to 329 adults in 2004/05. There is a slight trend of greater declines toward the south, but for the most part, the data show large reductions in returning adults throughout the California coast.

It appears that this phenomenon extends beyond California; preliminary and incomplete surveys of 22 streams through January in the Oregon Coast ESU found a mean decline in Coho returns of 70% relative to returns in 2004/05. Their estimate of 51,000 returning adults to the Oregon Coast ESU in 2007/08 is the lowest since 1999. Further, their data show the decline has been continuing for the past three years. Causation Although there are no shortage of potential contributors to the decline, including such wide ranging factors as poor fecundity of the 2004/05 yearclass; hydrologic flushing of fry prematurely to sea by high stream flows in 2005; increased predation by avian, pinniped, and/or other marine predators; and anthropogenic factors such as oil spills, fishing bycatch mortality, and survival during the spring–summer of both 2005 and 2006.

The Wells Ocean Productivity Index (WOPI), a composite index of 13 oceanographic variables and indices, weighted heavily by sea level height, sea surface temperature, upwelling index, and surface wind stress, has been used to accurately predict zooplankton, juvenile shortbelly rockfish, and common murre production along the California coast, and is thus a valid indicator of ocean productivity. Index values for the spring-summer of 2005 and 2006 were low, indicating poor conditions for growth and survival (Fig. 2). In fact, only the El Niño years (1982-83, 1992-93, 1999) had lower WOPI values. The WOPI assesses conditions on a local scale for California, but has tracked another index, the Northern Oscillation Index (NOI), which is based on the strength of the North Pacific high pressure cell and describes a broader region of the North Pacific Ocean. In 2005 and 2006, the WOPI decoupled from the NOI, suggesting local conditions on the California coast were worse than for the larger North Pacific region.

These results indicate that ocean conditions in the spring and summer, when juvenile Coho and Chinook salmon enter the ocean, were unfavorable to growth and survival. This may explain the poor returns of both Coho in 2007/08 and Chinook salmon in 2007. And, if the WOPI has predictive power, adult Chinook returns in 2008 should be low, supporting independent findings by the PFMC’s Salmon Technical Team, which reported a record low in the number of jacks returning to the Central Valley this past fall. Jack returns have been a useful predictor of run size in the next year, in this case, 2008. In 2007, only 2,000 jacks returned compared to the previous low of 10,000 and the long-term average of 40,000. Further Considerations Given the imperiled nature of Coho (2 of 2 ESUs listed by ESA) and Chinook salmon (10 of 13 ESUs listed) in California it is critical that coastwide instream monitoring programs be implemented and maintained to allow warning of impending problems to these valuable resources. Without the existing minimal monitoring effort, since Coho are not commercially fished or regulated, there would be little notice of their decline.

Further, the need for ocean monitoring on a consistent basis to understand the changing conditions, responses of salmon and other marine organisms, and to provide data to improve our ability to forecast impacts on marine resources, including California’s salmon, cannot be overemphasized. Implementation of ocean observing systems, as recommended by two independent federal reviews of ocean policy and California’s Proposition 40, would greatly improve our understanding of the ocean, which would benefit the sustainability of our valuable marine resources, as well as society in general. The dire situation evident this year also emphasizes the importance of genetically-diverse captive broodstocks, such as those at Warm Springs Dam on the Russian River and at the Fisheries Ecology Division laboratory (Southwest Fisheries Science Center, National Marine Fisheries Service) in Santa Cruz, which supplies mature fish and their gametes to Kingfisher Flat Hatchery, operated by the Monterey Bay Salmon & Trout Project, in the Scott Creek watershed. With fluctuating, and sometime adverse, ocean conditions that impact salmon over broad areas, maintaining a pool of broodstock derived from extant populations, may be the last best effort at preserving these stocks until more favorable conditions are reestablished.

A husband and wife came for counseling after 20 years of marriage. When asked what the problem was, the wife went into a passionate, painful tirade listing every problem they had ever had in the 20 years they had been married. She went on and on and on: neglect, lack of intimacy, emptiness, loneliness, feeling unloved and unlovable, an entire laundry list of unmet needs she had endured over the course of their marriage. Finally, after allowing this to go on for a sufficient length of time, the therapist got up, walked around the desk and, after asking the wife to stand, embraced and kissed her passionately as her husband watched with a raised eyebrow. The woman shut up and quietly sat down as though in a daze. The therapist turned to the husband and said, "This is what your wife needs at least three times a week. Can you do this?" The husband thought for a moment and replied, "Well, I can drop her off here on Mondays and Wednesdays, but on Fridays, I fish."

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