Mattole Salmon Chronicle - 1996-97 Season
| A Report by the Mattole Salmon Group - Report written by David Simpson, with assistance from Gary D. Peterson, Maureen Roche, and Michael Evenson.
In so far as many of the forces, such as history and the weather, that will help determine the salmon's future are beyond our control, it is not inaccurate to say that this past fall and winter, as in others, the Gods gave and they took. Relative to short-term survival of Mattole chinook and coho salmon runs, they gave more than they took. The outlook for the more distant future is, dare we say, still muddy. Upstream Woody Debris Structures Put to Bed In October, eight of the largest, most complex structures were placed in the upper mainstem with the aid of an excavator on Redwoods Monastery property and on the Sinkyone Wilderness State Park. The crew accomplishing the considerable labor was composed largely of commercial fishers hired through the federal Northwest Emergency Assistance Program (NEAP) and administered by the Humboldt and Mendocino Resource Conservation Districts. The last structure was actually being tied down on November 18th when rains began to swell the river. Though these structures were intended to provide cover and complexity of habitat for juvenile salmon, especially oversummering coho, they serve a subsidiary purpose of providing hiding places for wary adults moving upstream to spawn. A case in point: when Curtis Ihle, the NEAP coordinator, came in early December for an official evaluation of the structures we'd built, an 18 to 20 pound adult chinook male paid a more informal visit. While Curtis and MSG's Gary Peterson looked on, the chinook, in broad daylight, splashed up a riffle below them and immediately darted into the shadow of one of the digger log structures we'd placed earlier in the fall. A moment later, the fish darted upstream to hide beneath another, and then, after a brief rest, he flashed through open water to yet a third log structure. Though we cannot give the fish all the credit for the glowing evaluation our project ultimately received, we would gladly present him, posthumously of course, with the equivalent of a Mattole Salmon Academy Award for his impeccable and timely performance. Rumors that we had trained and indoctrinated the fish before releasing him above our trap at Ettersburg have no basis in reality. The Mouth Opening - Fall, l996 Meanwhile, downriver, there were actually two mouth openings, the first on October 26th after only 1.2" of rain in three days. Extreme high-low tidal variations may have played a role in the premature opening. It reclosed on the 8th of November and opened again, this time for the season, on the 17th of November. It was the third day of a 7-day series of storms that produced 10.1" of rain downstream (which could translate into 20 or more inches in some places upriver). This was the first and the mildest of three series of back-to-back storms that were to lash the Northcoast during the next six weeks. The Mattole Salmon Patrol - Today and Yesterday Some adult chinook entered the river after the premature opening and were subjected to the dangers of low freshwater flows. (Remember, salmon stop eating once they enter fresh water, and the ripening process relative to spawning accelerates. Their days, by then, are closely numbered.) The fish were stuck, in or just above the estuary/lagoon, for up to 12 days. Several instances of large fish (25+ pounds) trapped in relatively low-water pools or beached on riffles were brought to our attention. In at least two instances, successful rescues by concerned residents were accomplished. In another, a female chinook, with several thousand eggs, died on the beach where she had thrown herself in the early morning before help could come. It was heartening to know, though, that there were a number of people in the lower Mattole who cared enough to actually patrol the river bar looking for fish that might need help. How different from the mid-1970s when, for three years running, a drought cycle set in that created a fatal pattern for salmon. lnitial storms forced open the Mattole's mouth, and the salmon came into the lower river. Then the rains shut off - for as long as three weeks at a stretch. The fish were trapped, often over a hundred in a pool, in the lower river which had become almost as low and clear again as in summer. That time, the attention that the trapped fish got from humans was less, dare we say, sensitive to their situation. Hundreds, maybe even thousands, of the biggest chinook were speared, snagged, shot, netted, blown up. Some fish hunters in the Mattole and elsewhere on Northcoast streams were merciless. In those days, many folks still thought that the salmon were so numerous that they couldn't make a dent. Others just couldn't resist. Few of them had ever seen the increasingly empty spawning riffles upstream. One poacher bragged about killing, alone, 88 big chinook. All in all, a fair part of our long-range salmon abundance was taken away from us in those three years. Now we patrol the riverbar to help the salmon, every single fish being important to the future of the species. Times change. It can only be hoped that such abundance of salmon return to the river some day that we can again take a share. By then, we may have earned it. Continued forbearance by those who love to catch salmon for food or sport is an essential part of the effort and is to be congratulated.
When the big rains finally came last November, new fish entered the river and those that had been holding in such pools as existed in the lower river moved up toward the spawning grounds as rapidly as they could, reaching Ettersburg in 6 days. Colum Coyne supervised the first placement of our trap on the French's family property at Ettersburg on the 24th of November, and captured three coho salmon that night. The first chinook salmon came at 1:00 in the morning of the 26th. On the night of the 28th, we took five healthy chinook females, most of them close to ripe. We fished intermittently until early in the morning of the 4th of December when the onset of the next series of storms and a rapidly rising river forced us to remove the trap. The fish were generally healthy. The females were in the 16 to 20 pound range. Males averaged larger in size though not as large as we had seen earlier in the decade. It is safest to assume that most of the fish we saw at the trap were in the three-year-old age class, progeny of parents that spawned in the l993-94 season. Though there is no clear rule that equates age-class of fish to their size, the larger chinook are usually four and five years old. Chinook can live up to seven years and perhaps longer. (A race of salmon known as the 'June Hogs' from the upper Columbia River basin consistently reached an age of seven years old and average weights approaching 75 pounds. They were wiped out within a few years of the completion of the Grand Coulee dam.) The second series of late fall storms endured for several days. It was not until the 14th of December that we could put the trap back in and even then it was a precarious enterprise. Three people worked in the river that afternoon under higher water conditions than we'd ever attempted. Given that fish seem to move most when high waters recede, we fully expected that our foolhardiness would be rewarded during the night that followed by the appearance of many salmon eager to get upriver. All that we saw, though, was our first steelhead of 14-pound male, and an 8-pound chinook chub, the second two-year-old precocious male we had taken. Both were immediately released above the trap.
The appearance of chubs at the fish trap was an important and happy omen. Four of the two-year-old chinook males were trapped and released this fall. Though hardly a large number, they had the distinction of being progeny of the l994-95 spawning run. We had been concerned that a large storm in January of l995 had destroyed many or most of that year's eggs. The storm had followed on a dry November and December that forced most salmon to spawn lower in the river than was safe for their eggs - mostly below Ettersburg. Gravels there are generally more unstable and the larger flows that occur downstream are more apt to wash out spawning nests, also called redds. In addition, because of an administrative requirement of the California Department of Fish & Game (DFG), we were not allowed to trap fish and take eggs that year, so the contribution of juveniles our program usually makes did not occur. Our downstream migrant trapping near Petrolia during the late spring of l995 had turned up no chinook juveniles, an ominous sign. Clearly, though, a few fish from that year's run had survived, likely making it downriver to the mouth before we began our juvenile trapping. The presence of chubs means that there will probably be at least some three-year-old chinook returning to spawn in the late fall and early winter of 1997-98. The three-year age class of chinook in recent years has provided the largest numerical returns here and throughout most of the state. (A decline in the average age of salmon caught at sea or returning to spawn is considered by biologists to be a rough indication of overharvest at sea. Fewer fish live to be four or five years old.) Based on what we know, even including the presence of a few chubs, it would be unduly optimistic to predict a good run for the l997-98 season. It may depend largely on the presence of four-year-old fish. The prediction of the onset of another El Niño also does not portend a great fish year. El Niño years make for poor feed conditions in the ocean and diminished survival.
We continued to operate the trap on and off until the night of December 20th when the third and largest of the series of storms struck. This was the series that was to produce the New Year's Day high water of l997. We removed the trap by the skin of our teeth by 3:00 in the morning of the Winter Solstice. We did not trap again that season, and we did not have a compelling need to. In a relatively short trapping period during which we only removed the trap twice, we managed to take sufficient male and female chinook to provide the eggs and milt we needed for our hatchboxes. (We were unable to incubate and rear salmon at our Squaw Creek site this year due to problems with the water system. We hope to have the problems solved for this coming season.) All in all, we took 20 adult chinook, 8 females and 12 males. We also trapped and released 4 coho females and 4 males. We took 28,000 eggs from eight female chinook and reared 17,000 for spring release. The remaining fish are being reared for fall release by Tim and Laura Day at our facility at Solitude near the headwaters of the South Fork of Bear Creek. One other item worthy of mention is that we saw several adult chinook at the trap and one on the spawning grounds that had a distinctive mark, a clipped maxillary, indicating they were returns from some of our past releases. For the past four years, we have been clipping the end of the maxillary of all fish we incubate and rear before their release. It allows us to make rough determinations of the contribution our program is making to the salmon population. We look for the maxillary clips at two points in the life cycle of the fish: when they migrate downstream and when they return to spawn. At least as important, the mark enables us to distinguish and release returning spawners that we originally incubated. This care assures us that we will not inbreed any characteristics that might result from more than one generation of artificial propagation. (The maxillary is not a fin but the ridge of bony tissue that runs along the top lip of salmon and many other species of fish. We traditionally clip off the tip of the maxillary on the right side of the fish's mouth.)
We have been trapping adult salmon now for 17 years and have learned that, within the basic patterns, each season is entirely different. There are seasons when, for whatever reasons, we manage to trap the adults we need for egg-taking though there seem to be few fish in the river. This was not one of those. The relative ease with which we managed to take spawners for our hatchbox program was reflected in numbers of fish our surveyors saw upriver. Those of you who read our report in the fall 1996 MRC Newsletter (issue #11, page 10) will recall that we had just entered into a cooperative project with the Bureau of Land Management (BLM), represented by fisheries biologist Dave Fuller, to gather salmon-related information about Bear Creek. Part of that plan called for spawner surveys and carcass counts specifically on Bear Creek and on our primary index reach in the upper Mattole, the top 4.7 miles of the mainstem likely to be used by salmon. (Through comprehensive surveys in the early l980s we determined that, during a fall and early winter of at least average rainfall, about 10% of all the salmon which spawned in the river or tributaries, were likely to use that reach.) Several other reaches of the mainstem and tributaries where salmon have been seen in the past were also surveyed, though less intensively. Gary Peterson, after a brief rest from his summertime instream habitat work, organized these surveys. The results were very exciting for us. During too many recent years, the upper mainstem index reach had looked like a salmon neutron bomb had gone off, leaving a perfectly habitable place - clean spawning gravel and relatively high water quality - but no fish to use it. During the 1996-97 spawning season, the upriver ghost town came back to life. There were fish! Not necessarily just like the old days, but quite a few spawning salmon. Nothing spectral about them. You could see them splashing on riffles, or better, you could walk quietly along the banks and actually watch the females digging redds or the males jousting for position. In the index reach, 70 distinct redds were identified by surveyors. Only one coho salmon carcass was observed while 29 chinook carcasses or skeletons were identified. Thirty-three live chinook and eight live coho were seen. Another concentration of chinook spawning was seen downstream of the index reach, near Thorn junction. A dozen chinook redds were clearly identified, half before the New Year's storm and half after. On South Fork Bear Creek, upstream from the Shelter Cove Road, 29 coho redds and 3 chinook redds were identified. Ten other redds, probably made by salmon as opposed to steelhead, were spotted. Ten live coho and six carcasses were seen. Most of the redds were in the upper 1.5 miles of the creek. This represents the largest concentration of coho spawning we have seen in one stretch of the Mattole since we first began to survey in l981. In l995-96, Bear Creek was almost entirely without sign of coho. Annual electroshock surveys by the local DFG biologist, Larry Preston, turned up sufficiently few juvenile fish to warrant the release into Bear Creek of coho fingerlings from parents that we had trapped at Ettersburg in the fall. (We have an ongoing informal agreement with DFG that our coho releases will be tuned to their electrofishing surveys. This allows us to release coho where they will have the least competition for food and cover. More on this subject in the discussion of our downstream migrant trapping at Ettersburg.) Thompson Creek was another hotspot - eight coho redds in a tributary, Danny's Creek (named after the man who once complained that those big chinook spawning in the creek right below his cabin were so noisy that he couldn't sleep). Three chinook redds down-stream near the mouth of Thompson were also spotted. On Bridge Creek, surveyors saw five live chinook, all large, and at least three redds and one carcass. A coho female was spotted in Baker Creek below the county road after the first of the year. No surveys were done in the other four major tributaries, the Upper and Lower North Forks, Honeydew Creek and Squaw Creek. Also, we were not able to look carefully downstream in the mainstem below Nooning Creek where we have seen concentrations of spawners in the past. All in all, it seems that this past season's was our best salmon spawning run since l986-87. We have estimated that 1,000 or more chinook returned to the Mattole to spawn and at least 300 coho. This lends continued credence to our sense that the numbers of salmon returning to spawn in the Mattole have been increasing slowly every year since l990. While the sight of several fish on one spawning riffle does not mean that salmon salvation is assured, it does allow the hopeful observer to imagine a time when there are so many fish on the riffles that they are digging up each other's redds. This, of course, would be the clearest signal that there are surpluses for harvest. (Spawning gravel carrying capacity is actually the basis for determining many commercial fishing 'openings' in Alaska.) To complete the survey report, we saw few steelhead in the trap or on the spawning grounds during the peak salmon run from early December through mid-January. Reports reached us of concentrations of fish holding in upriver pools in late January and in February. Steelhead anglers had considerable success in the lower Mattole after the river had cleared several weeks after the New Year's high water. (Note: the Upper North Fork produced so much sediment in early 1997 that visibility downstream for fishing was limited for weeks after each storm.) Information from steelhead anglers, together with that gained at the downstream trap, to be discussed later, indicate that Mattole winter-run steelhead, unlike the salmon, are some distance from a serious threat of extinction.
The late December rains produced the third highest streamflows measured in the lower Mattole this century. The 1955 flood saw flows in excess of 90,000 cubic feet per second (cfs) while 1964 produced 78,000 cfs. On January 1st, 1997, according to the U.S. Geological Survey gauge at the Petrolia Bridge, flows exceeded 73,000 cfs. In Petrolia, rainfall for December reached almost 40 inches, while residents on Wilder Ridge measured more than 70. It is impossible to be accurate in detail about the effects of all this rainfall and of the high streamflows. In the lower valley, at least, new wounds, like pock marks, opened up in recovering hillslope vegetation. These were largely, but not exclusively, the telltale signs of more abandoned roads resuming, through fill failures or upslope slides or slumping, the original angles of their host hillslopes. In the long run, this seems part of a shakedown process that is inevitable. It is probably healthier to look at it not so much as our history haunting us as the impact of that history being slowly, necessarily, undone. Let us pray for wisdom in the future as we put in other roads or struggle to maintain those we still use. Upriver, less damage was visible. The mainstem was remarkably stable, given the amount of water that moved in the last week of December. Certainly, the habitat enhancement structures that our crews built were minimally disturbed. All but one of 57 remained entirely in place, and the one that moved was the only structure that had not been completely secured before November 18th's rising flows. But it was in the lower river channel that the impacts of the New Year's Day flood could be most readily seen. The river channel, especially below the Lower North Fork, whip-lashed back and forth across its floodplain causing the loss of considerable new acreage of relatively stable riparian forest and the sloughing off of considerable stretches of previously stable bank. One of the most glaring manifestations of the power of the flood was at the Rathbun home where a 30-foot-high bank adjacent to the house began to calve off in substantial chunks as the high waters receded. A row of well-established pines, several old bay laurel clusters and a dense stand of 20-year-old willow and alder were eaten by the river. The Rathbuns had built a rock wing-dam just upriver of their house after the March l975 high water that effectively protected their home in the years since. The new storm, though, produced a major channel shift, one of many such shifts in the lower river, that circumvented the protections for their home that the wing-dam provided. Major sources of the sediment that played a potent role in this channel instability were produced by the lower and upper North Forks. Always sediment producers, the North Forks struggled under the burden of vast amounts of new sediment coming from upstream. One landowner near the confluence of the lower North Fork with the mainstem had to struggle for over a week, using his Cat to try to keep the stream from leaping its banks and taking his business establishment and the county road bridge. Several other homes in the lower North Fork floodplain were in danger. New buildup of sediment in the channels and floodplains of both North Forks and in the mainstem, especially below the lower North Fork, further limit the capacity of the streams to contain high flows and to effectively dissipate overflows. Storms that will come in future winters could easily create a disaster for residents both in the lower North Fork drainage and in the 4.5 miles of the mainstem floodplain between the North Fork mouth and the ocean. The potential impact of these silt-related channel shifts and bank losses to the fish are substantial. From the Rathbuns on down, an already exposed and barren summertime channel was deprived of much of what little shade, cover and complexity of habitat had not been lost to earlier storms. Smolting salmon and steelhead (seaward-migrating juveniles) have to navigate through this stretch to reach the estuary and ocean. Waters entering this stretch in late June, July and August are already superheated, often up to 80 degrees Fahrenheit. This heat, combined with the almost total lack of pools or protective cover, make this stretch a menacing challenge for salmon and a great fishing reach for herons and other fishing species. Juvenile salmon and steelhead cannot easily escape predation unless they have deeper water or cover, both of which are largely lacking in the two miles of river just above the estuary. With the exception of a few backwater pools where cool water has become trapped or where springs or colder creeks enter the channel, the lower Mattole is a broad and largely barren heat sink, a gauntlet that juvenile salmon and steelhead must run just before reaching the ocean. Given these obvious threats related to the amount of sediment coming down the lower North Fork and into the mainstem Mattole, one must look with a certain concern, if not outright dread, at Pacific Lumber Company's plans to clearcut, during the next 15 years, most of the previously undisturbed old fir timber on 3,000 of the nearly 12,000 acres it owns in the drainages of the North Forks, most in the lower North Fork. This concern should not be dismissed as overheated environmentalism. Given the newly elevated channels of the lower North Fork and the Mattole mainstem, we would be fools not to take heed. And given the need our chinook have of a healthy deep-water habitat in the lower river and estuarine system in order for the population to make a full recovery, Mattole salmon and the downriver human community are clearly locked into a shared fate. Each year, in mid to late spring, depending on water conditions, the Salmon Group deploys a trap in the lower river to examine a representative sample of juvenile salmon and steelhead moving downstream toward the ocean. This usually amounts to anywhere from 5% to 30% of the migrating fish which are counted, identified to species, in some cases weighed and measured, and then released back into the river. An every other night scenario is sometimes employed, but more often, we trap several nights running during certain periods, usually around the new moons. That is when scientists have found salmonids are most likely to experience an intensification of characteristics called smolting. These are the physical and physiological changes the juveniles undergo preparatory to entering salt water. What usually show up in our trap are young-of-the-year, year-old and two-year-old steelhead, young-of-the-year chinook, and a few year-old coho. Most of the coho smolts are already downriver and out to sea before streamflows are reduced enough to allow us to set our trap. Our ambition in all this is to help determine population size and health, and spawning and incubating success. Two elements were different this year. One was the trap itself. In past years we used, for the purposes of sampling downstream migrants, a fyke net. The wide-mouthed, long net tapers down and connects to two live boxes in which the trapped fish sit until morning when they are identified to species, counted and released. Putting the trap in and operating it effectively are mildly graceless and lengthy chores and can only be accomplished when streamflows decline considerably. This year, we had the use of a 'rotary screw' trap, borrowed from the U.S. Fish & Wildlife Service, that earns its name by a large rotating screw within a drum that guides the fish into its own live box. It looks for all the world like a shiny, floating cement mixer, but it is tremendously effective, given the right placement in the flow. Also, since it is designed to pass debris out of the live box, it is easier on the fish that are trapped. (Fish occasionally suffer bruising and loss of scales when too many leaves, sticks and other debris become entrained in the fyke system.) The second element that was different this year was the fact that we had adequate funding. BLM had been instrumental in arranging funding for the downstream trapping from the California Coastal Conservancy. It enabled us to operate with consistency.
The other major difference this year in the downstream migrant trapping is that, instead of starting in late May when flows are low enough downriver for a fyke trap, we started in late March and not in the lower river but in Bear Creek near its confluence with the mainstem on land belonging to the French family in the Ettersburg area. The agreement with BLM through which we gained the use of the screw trap allowed us this rare opportunity to uncover some of the salmon mysteries of Bear Creek. The exceptionally regular early-morning volunteerism at the trap by Colum Coyne was the other factor that allowed us gain new insight into this, the longest tributary of the Mattole. Spawner surveys on Bear Creek for the past 10 years had been inconclusive, not turning up many chinook, but they were not being systematic enough to allow us to draw conclusions. Even this year, when our surveys had been relatively extensive, there were large stretches of the creek that, because of difficulty of access and just plain lack of time, went unsurveyed. Where we did manage to survey, only three distinct chinook redds and one pair of live chinook adults were observed. On March 20th, the first day of downstream migrant trapping, only one chinook fry made an appearance. During the next five nights of trapping, only an occasional chinook downmigrant showed up and one or two year-old coho. Suddenly, on the night of the 26th, 100 chinook fry entered the trap followed by 200 the next night. Since the trap covered no more than a third of the entire creek's flow, these numbers represent only a part of each night's migration. The numbers of juvenile chinook for the next 17 days averaged about 140 fish per night with a high of 343 on April 7th. One could deduce that up to 400 chinook a night were moving downstream past the trap site. After the 18th of April, numbers declined dramatically until the morning of May 16th when another surprise greeted us. There were 336 chinook fingerlings with our mark (right maxillary clip) in the trap, compared to 58 unmarked fish. What is most remarkable about this is that we had released the marked fish at Solitude in the upper South Fork of Bear Creek less than three days earlier. They had traveled the 16 miles in no more than 66 hours. That translates to a migration rate of nearly 6 miles per day. These young chinook were determined to get downriver in a hurry. We trapped at the Ettersburg-Bear Creek site only a few more days, until the 20th of May. Chinook numbers, marked or unmarked, were declining rapidly again, and Colum, our most dedicated volunteer, was beginning to show signs of growing fins, an eventuality his wife and children would most likely wish to avoid. By that time, we had taken and released a total of 3,970 young chinook, 595 of which were marked, 6,096 young-of-the-year steelhead, 668 year-old and two-year-old steelhead and 205 year-old coho, 104 coho young-of-the-year, and an assortment of adult lampreys, ammocoetes (lamprey larvae), sticklebacks and yellow-legged frogs. Fascinating and potentially important information about coho emerged. The naturally spawned coho young-of-the-year were, surprisingly, outnumbered two-to-one by fish that we had spawned out and released into Bear Creek, as fingerlings, in June 1996, about a year earlier. The release had been authorized after our spawner survey and a subsequent DFG survey for juveniles determined that there were very few young coho in Bear Creek that spring. It turned out that our stocking was appropriate, even critical, in maintaining continuity of coho use of Bear Creek. It also showed that releasing coho in their first spring of life into good habitat can be effective. (We owe a special vote of thanks to Richard and Sally French, and to Garrett and Melinda French, for allowing us to operate the downstream migrant trap on their property along Bear Creek. By so doing, they chose to put concerns for the future of the salmon above fears that information generated by our surveys could be used to limit the uses to which they put their land. Such simple openness and good citizenship has been a benchmark of their family's relationship to the Ettersburg area for several generations.)
On May 23rd, we put the screw trap in upriver of Rex Rathbun's wing-dam, not far upstream of Mill Creek and approximately 3 miles from the mouth of the Mattole. We operated the trap there for 31 of the next 42 nights. During that time, we sampled a total of 5,643 chinook smolts and an estimated 25,000 juvenile steelhead. Of the chinook, 910, or 16%, had our maxillary clip. This was an important statistic though difficult to interpret because there was no way of knowing whether this ratio was consistent throughout the season. Most likely, a good part of the annual chinook down-migration was already in progress before our ponded fish were even released, meaning that a lot of fish had passed us by before we moved the screw trap downriver and before the marked chinook we released had mixed with the whole population. Still, the 16% addition to the segment of the population we were able to monitor has to be considered significant, given that they came from a release of an approximate total of only 17,000 fish. We have been making the assumption that the 75% to 95% egg-to-fry survival rate of eggs we take for our program (from a very small percentage of the total adult return) is 3 or 4 times the rate for naturally spawning fish. Thus the overall odds for survival of juvenile chinook are shifted slightly in favor of the salmon. The 16% figure (the percent of the entire down-migration that fish from our program composed) seems to reinforce the assumption about our contribution. At the same time, it may indicate that the natural survival rate this year was lower than we had hoped. The overall egg-to-fry survival rate in the wild may actually go as low as 10% or even lower, especially in years where massive post-spawning storms wipe out redds, as we suspect happened in January l995. Without being able to determine what percentage of the run we actually sampled at the mainstem trap near Mill Creek this year, no really accurate estimates can be made. The huge storm that culminated in January l997 might have destroyed some eggs in redds, though certainly not to the extent that the January l995 storm did. Again, when salmon reach the headwaters reaches to spawn the likelihood of eggs surviving is much greater. Rescue Rearing The mouth of the river closed on the morning of June 21st, coincident with the official arrival of summer. From 1984 to the present, the date of initial mouth closure has varied widely, ranging from late May (1987) to early September (1990). Since 1984, the approximate average date of closure has been early July. It is important to note as briefly as possible here that most Mattole chinook migrate downstream as juveniles in their first few months of life, starting soon after they emerge from the gravel. Much of the migration takes place in April, May and June when the water begins to heat up in the increasing sunlight, a situation rendered abnormal only because there is less shade all along the mainstem channel. More solar exposure means higher temperatures. By the time the mouth closed this year, we were experiencing daytime high water temperatures of 78, 79 and even 80 degrees. This level of heat is not healthy for juvenile chinook, which have less tolerance for high temperatures than do steelhead with whom they share the late spring downstream migration. All things being equal, many chinook juveniles would actually choose to stay in fresh water for their first summer. Many biologists suggest that this is the optimum scenario, that chinook that spend their first summer in fresh water are three or four times more likely to survive to adulthood than juvenile fish that enter the ocean in the late spring. Mattole chinook rarely gain that advantage now. Increasing stream temperatures more or less force them toward the only cold water available - the sea. Even that less-than-perfect avenue for potential survival is denied them when the mouth closes. They are stuck, until fall rains come, in a lagoon that is hot, shallow and relatively devoid of cover or complexity of habitat. This narrative leads us right back to l986-87, the season we have cited as a benchmark. There were good rains in the fall of l986. There were plenty of salmon, relatively speaking, and they were able to reach the best headwaters spawning reaches. Productivity was high. Our hatchbox program released over 50,000 chinook juveniles into the river to join the abundant early spring down-migration. In retrospect, it would have been better had we held onto some of our young fish until the end of the summer as we do now. Because the rains, earlier so perfect, now failed and a dry, hot spring ensued. On May 26th, the mouth closed for the rest of the warm months. It was and still is the earliest closure since we started watching the mouth. It's hard to say exactly how many young chinook were trapped in the river. We were working with BLM and Humboldt State University (HSU) graduate students at that time in research about the use chinook make of the Mattole estuary/lagoon system. Part of our work was making population estimates, seining and counting and subjecting sample numbers to a formula that gave us a ballpark figure. The population estimate in late June 1987 was about 110,000 juvenile chinook. By late August, about a month and a half before the mouth reopened, that number had been reduced to near zero. Thus did we lose nearly an entire year class of chinook in the best spawning year the Mattole has had in over a decade. Three years later, in l990, the fewest adult chinook returned to our river to spawn since salmon first came here. It was that disaster, taking place so quietly and so far beneath the notice of most of us, that forced us to reorder our thinking about the salmon and the watershed. It was clear that problems of warm water and silted-in pools in the lower river would not be quickly remedied. We, and the salmon, would have to wait for decades, maybe centuries, for the whole watershed to recover. All of this has been thoroughly discussed and documented in many Mattole publications, especially Dynamics of Recovery, published in early l995 by the Mattole Restoration Council. A key element in our response to the perceived ongoing crises in the estuary/lagoon system was what we now call 'rescue rearing.' This requires taking a number of chinook juveniles from the later stage of the downstream migration and placing them in our rearing pond at the Rathbuns for the rest of the summer. The water source there, from a tributary of Mill Creek, almost never exceeds 62 degrees. We reasoned that the fish were more likely to survive as juveniles, once the mouth closed, than if left in the river. We also reasoned that the young chinook had already gone through the imprinting process while migrating down-stream and had achieved some level of natural adaptation. We felt that what we were doing was emulating the optimum scenario for the salmon - staying in fresh, cool water in the lower river for their first summer. DFG was at first cold to our arguments. It presented a somewhat radical departure from known population enhancement techniques. In l994, they gave us permission for a small experimental program of rescue rearing. We trapped and reared 500 chinook smolts with great success. But after that, despite the success, DFG withdrew permission - until this year. When the mouth closed on the summer solstice, we conferred with Larry Preston, DFG Region 1 biologist based in Eureka. Larry figured, like us, that there was a very good chance that most of the juvenile chinook remaining in the lower river would not survive the heat of summer. He also knew that our earlier experiment had worked and that smolts diverted from their down-migration could make a quick adaptation to a rearing pond and survive through the summer nicely. On June 22nd, DFG gave us permission to divert as many chinook as possible into our rearing tank. Over the next 15 days, we managed to divert 1,100 healthy chinook into the pond at the Rathbuns. Mortalities, immediate or delayed, were very low and substantiated our sense that the new screw trap is gentle on the young fish. The only problem, if it could be called a problem, was the huge numbers of juvenile steelhead we had to handle to identify and divert the chinook. Once the diversion strategy went into action we essentially stopped counting and weighing steelhead, but on the one day we did count, there were 2,400 steelhead. It is likely that, for most of those 15 days, we were dealing with 2,000 to 3,000 steelhead of three age classes. There were so many fish in the trap when we opened it on some mornings that it was difficult to see the shiny bottom of the live box. The box was literally black with fish. Again, though, mortality rates were very low. At this writing, we are recovering from a near-tragic occurrence at the Rathbun pond. Early in August, we began to notice signs that our diverted chinook were not fully healthy. The avidity with which they fed began to fall off and they showed signs of discomfort. The first mortalities were among the weakest fish, those that had taken least well to a new artificial feeding regime. Soon after, some of our marked fish began to go belly up. These were the biggest and best fed since they had been pond-reared in March and early April before being released to join with the naturally-spawned fish in their down-migration. By the time we diagnosed the presence of a skin parasite called 'ich' and began treatment (prescribed by the DFG pathologist, and with the assistance of DFG rearing coordinator Linda Radford), we had lost half of the fish in our pond. It was our first experience with a problem that has plagued rearing programs throughout the region. Taking fish from the river, rather than from eggs we had incubated, was at the heart of the problem. The parasite can live among fish while in the river but does not achieve fatal or epidemic proportions until those fish are concentrated in a relatively small volume of water. The losses were extremely painful because the fish had adapted so well and, of course, were so important. We have settled on a simple prophylactic technique for treating diverted fish in the future, as a matter of course. This problem should not arise again. Others, no doubt, will. By early October, water temperatures had declined and a rain or two had roiled and raised the river. On October 10th, we released 500 large, healthy rescue-reared chinook into the mainstem Mattole at the confluence of Mill Creek. A little later in the fall, when flows upriver have increased, we will mark and release the 6,000 juvenile chinook we incubated and reared over the summer at Solitude on Bear Creek. (A note, it is our hope to bring the Squaw Creek rearing facility back on line again by the spring of 1998. This facility was dormant this year due to the need of extensive equipment repair.)
If there is an endangered salmonid subspecies on the Mattole, it is the summer-run steelhead, a fish that provides a transcendent example of patience. Summer steelhead appear to be a distinct population of smaller adult fish that enter the river in April and May. They swim upstream a certain distance and then hole up through the entire summer. There, they achieve a torpor-like state that resembles hibernation though they are responding to warmer rather than colder environmental conditions. This 'estivation,' as it is called, allows them to reduce their metabolism. They spend most of their time sitting and waiting until the first fall storms bring water levels up. Then the summer steelhead moves up quickly to spawn. Once it completes its spawning, the fish rapidly head downstream toward the ocean, not unlikely passing the first winter-run steelhead heading upriver. No research yet exists to prove that summer steelhead are a genetically distinct stock. For that matter, it cannot be proven genetically that Mattole steelhead are in any way distinct from our resident rainbow trout. The species as a whole presents us with a series of unanswered questions. This year, for the second running, our woman underwater, Maureen Roche, organized a dive in search of the mysterious summer steelhead. She enlisted the help of ten Mattole residents and Tom Weseloh of CalTrout, one of Humboldt's great fish-heads. An AmeriCorps volunteer also came along, rounding out the crew that dove during three days in mid-July. They covered 39.2 miles of the river from above Arcanum Ranch, near the headwaters, to the estuary, including the lower portions of three key tributaries. It was the second consecutive year Maureen had arranged a summer steelhead dive on the Mattole. In l996, the group that dove was composed largely of people from outside the valley, including two biologists from the U.S. Fish and Wildlife Service, two AmeriCorps volunteers and Tom Weseloh. The parameters for distinguishing a summer steelhead have to do with size. Generally speaking, any fish in the river after the mouth closes that is over 16" long is thought to be a summer steelhead. They usually get no bigger than about 24", although 28" and 30" fish have been observed in the Mattole. Fish smaller than the 16" threshold but over 12" long are thought to be too large to be two-year-old steelhead smolts or resident rainbow trout. We identify them as 'half-pounders,' immature steelhead that return from the ocean after only one year and often end up trapped in fresh water for the summer. During this year's dive, 18 summer steelhead were identified, almost all of them in the mainstem Mattole between the ocean and the Nooning falls, 50 river-miles upstream. Last year, only 13 were observed in the same stretch. None were seen above Nooning in either year. Interestingly, the fish did not seem to seek out deep pools or cold-water sources. Most were immediately downstream of substantial riffles in well-oxygenated water. Maureen spotted a 30" fish and a 32-incher was spotted last year. (The first organized diving survey for summer steelhead on the Mattole took place in l982 and was organized by the Department of Fish and Game. In l991, HSU's Cooperative Fishery Research Unit organized a second dive. Neither of these dives succeeded in spotting or identifying a single summer steelhead.) An historical note about summer steelhead: in a l943 memoir about fish in the Mattole, famous orchardist Albert Etter wrote about seeing 200 to 300 'rainbows' between 14" and 24" in a pool near Ettersburg in October l942, probably early enough in the season to indicate that they were not fish that had just entered the river. According to him, the Harrow boys had reported seeing a similar school 3 or 4 miles downriver several years before. These fish may indeed have been summer steelhead. We learned other important things from this summer's dive. The presence of significant numbers of oversummering coho juveniles close to the headwaters was confirmed which was an expectable presence, given the data from spawner surveys the previous fall. What was less expectable was the presence of chinook young-of-the-year. Chinook generally begin the smolting process soon after emerging from their natal gravels. That is, they begin the physical transformation preparatory to entering the ocean, and at the same time they begin to migrate downstream. We have heard reports from other watersheds that some juvenile chinook take residence near the headwaters during their first summer, but last year and this were the first times we actually witnessed this phenomenon in the Mattole. Though Maureen did not observe large numbers of young chinook, there were enough scattered observations this year and last to lead us to believe it is likely a reoccurring event. As a last note from underwater: Maureen, diving in the lagoon on September 21st, observed a number of chinook smolts that she estimated to be in excess of 6,700. Since high daytime water temperatures, potentially of mortal danger to chinook, had peaked and begun to decline by then, it is reasonable to assume that most of those fish survived to enter the ocean when the mouth opened up a few days later, on September 25th. The survival of some juvenile chinook in the lagoon is very heartening since, as stated earlier, fish that stay in the river, and survive, for their first summer are much more likely to reach adulthood and return to spawn than those that enter the ocean in their first spring. It does, though, suggest some reexamination of our long-range plans for rescue rearing of downstream migrant chinook. What may be involved here is a carrying capacity issue; that is, the great die-off of l987 may have had to do with the excessive numbers of chinook that were trapped in the lagoon by the early mouth closure. It is common in nature, when populations exceed carrying capacity, that the numbers that die off are far in excess of simply the surplus individuals. The 6,700 or so chinook that seemed to have survived this summer in the lagoon, despite high daily water temperatures that several times reached 80 degrees F, might have been a more or less optimum number relative to the reduced carrying capacity of the estuary/lagoon system. The premature opening on September 25th, it should be mentioned, related less to the small rains (1.8" total, in September) prior to that date than to 15' high waves precipitated by substantial storms in the Gulf of Alaska. On September 28th, the mouth closed again only to open early on October 2nd after almost 3 inches of rain on October 1st. The mouth closed again on October 16th. There have been very scattered sightings of adult salmon in the river since the October 2nd opening. The best part of the run is likely still waiting offshore. Stream Temperature Monitoring Summertime stream temperatures affect coho salmon perhaps even more than chinook. Coho rarely go out to sea before the early spring of their second year. Most stay in or near the stream reaches where they were incubated. Biologists, including those with the National Marine Fisheries Service (NMFS) who administer the Endangered Species Act for coho, believe that summertime stream temperatures are the single most critical factor in determining utility of habitat for coho. Within the historic geographic range of coho, streams where daily high water temperatures do not exceed a threshold of 68 degrees Fahrenheit are considered potential coho habitat by NMFS. We began temperature monitoring, in cooperation with the California Cooperative Fisheries Research Unit at HSU, in the Mattole estuary/lagoon during the summer of l985 and maintained two thermograph monitors each summer until l992. In l993, MSG assumed the annual monitoring of the two stations in the estuary/lagoon. In l994, Redwood Sciences Laboratory added six temperature monitors in areas where they were carrying out research on intermittent streams in managed and unmanaged forests in the Mattole. Since then, under the heightened pressure of the threat and then the reality of the coho listing, stream temperature monitors have proliferated like rabbits. Between l995 and l997, the Salmon Group purchased and deployed 37 computerized temperature monitors. (Other monitors now potentially in summertime use in the Mattole: Redwood Sciences Laboratory - 17; DFG - 5; BLM - 5; Pacific Lumber Company - 6; Barnum Timber Company - 5 - a grand total of 75 monitors for the Mattole). A few of these monitors are reserved for measuring air temperatures at various points in the watershed. The remainder are leashed in place underwater in the spring, usually by a diver (MSG's are placed by Maureen), and retrieved in the early fall, hopefully before the river experiences a considerable rise. Results from the summer of l996 can be found in a map in the most recent MRC Newsletter (issue #12, summer 1997, page 4). To sum it up, 30 of the 50 instream sites being monitored that summer were cool (high temperatures less than 68 degrees F), correlated with an overstory of conifers. All the 20 others were too warm for salmon - mostly those from Eubanks Creek on down. Needless to say, there were no coho or chinook juveniles observed in the mainstem Mattole below Eubanks Creek during the summer of 1996. In an interesting side note, it seems that steelhead may be highly dependent on cold pools and cold seeps or springs that upwell underwater for their summertime survival. An excellent case in point is the mouth of Mill Creek, southwest of Petrolia. There, each summer afternoon when water temperatures stoke up toward the high seventies, several hundred young steelhead of many sizes can be seen sitting absolutely peaceful and still in the pool below the Mill Creek mouth. Fish that might otherwise be hunting each other seem to make a temporary truce, not unlike at an African watering hole, and wait out the heat of day together. The fish quickly disperse, almost as if at signal, to take up the hunt along nearby glides and riffles, as soon as the water temperature begins to decline. This phenomenon may hold true wherever there is an intrusion of cold water or a layer of cold water trapped near the bottom of deep pools.
Another Salmon Group monitoring project that bears mention is our survey, in cooperation with BLM, of insects that live in the stream. Called aquatic macroinvertebrates by the biologists, these underwater bugs may offer us a new way to determine the relative quality of the water and instream habitat. The underlying assumption here is that clean water and clean gravels should have a full complement of those insects that we know to thrive in good-quality streams and fewer, if any, of those insects that we know are more tolerant of pollution (e.g., thermal loading, chemical pollution, sedimented streambottoms, etc.). It is a reasonable assumption, but our knowledge of which insects do what and when is still somewhat limited. The project was actually initiated as a way of tracking changes in water quality in the upper reaches of the South Fork of Bear Creek. The paving of almost three miles of the Chemise Mountain Road, upstream of the junction with the Shelter Cove Road, was a compelling factor. It is generally thought that this paving, and that of the Briceland-Thorn Road along the prime spawning reaches in the upper mainstem of the Mattole, were going to have positive impacts on stream quality and thus on salmon. The sampling project seemed a reasonable way to monitor some of the potential impacts. The sampling is simple. All the rocks from three subsets, areas one foot by two feet and six inches deep, on a riffle along a randomly selected transect of the stream, are scrubbed so that all the insects and larvae flow into a kick net. The catch of eggs, instars (eggs at more advanced stages), larvae and emerging insects just short of the flight stage are then preserved in alcohol and sent off to BLM's laboratory in Utah for species identification. Sampling is done during both of the two annual hatch periods, in May and in October. On South Fork Bear Creek, this sampling was done in l996 and again this year. Five other samplings were conducted at tributary sites having good spawning gravels and where temperature monitors were already in place. For those unclear as to what creatures are actually being sampled, some of the most common species are known as mayflies and caddisflies. One species is known as the salmonfly or alderfly which achieves a length of 2 inches or more. Damselflies and dragonflies are often even larger. The results in l996 and, it seems, l997 were good though inconclusive, largely because of the lack of sufficient understanding of the sensitivity of various insects to pollutants, especially to silt. By all available standards, the areas monitored showed no evidence of toxicity to the aquatic insects we sampled. In general, there seems to be considerable abundance and diversity at all sites sampled. Biologists are wary of drawing more conclusions than that from the two years of monitoring because of the fuzziness still inherent in the whole process. Also, all of the l997 samples have not yet been analyzed in the lab so we don't yet know what, if any, responses there have been in the insect communities to the paving. But to emphasize, so far, the insect communities of South Fork Bear Creek and, likely, the upper Mattole seem to be in good health. Riparian Recovery Work A last Salmon Group effort that must be briefly discussed is an experiment in riparian recovery. It is well known that streamside riparian habitat has endured perhaps more damage than any other habitat type in the Mattole. It is also well known that the riparian zone is critical for stream health in several respects. Primarily, it provides layers of shade canopy that moderate summertime water temperatures, contributes woody debris to the stream channel for fish habitat, produces an enormous amount of finer organic matter to the stream, much of which provides food for the fish,and filters upslope sediments and other potential pollutants before they reach the stream zone. Loss of riparian habitat in the Mattole to silt-related flooding and direct harvest has had devastating impacts on the fish. For almost two decades, we and others have been working to restore riparian vegetation and to stabilize eroding banks. We have been especially involved in planting the two most visible and widespread riparian tree species, alders and willows. Since l980, literally millions of alder seedlings and willow stakes have been planted on North Coast streams by the California Conservation Corps and others, including the Mattole Salmon Group. Many of these plantings have been extremely successful, forming the basis for whole new young riparian forests or bringing stream temperatures down by as much as 18 degrees F. Other plantings have been swept away all over again by floods. Even the most successful of these plantings has, at best, restored only one component of a diverse riparian system. Other riparian species have been largely ignored for variety of reasons including expense of propagation and planting. Alders and willows are easy and cheap to reproduce. They do not, though, allow for the fullest functioning of riparian forest. They do not contribute, for instance, woody debris as potentially large and durable as streamside Douglas-fir. With this in mind, Salmon Group crews planted several hundred each of Douglas-fir, Oregon Ash, Pepper wood and Big-Leaf Maple last summer on a selected site in the lower river, across from the mouth of Mill Creek. Michael Evenson developed and coordinated the project. A deep toe trench was dug by a backhoe and partly filled with compressed strawboard and woody debris. Silt and riparian soils were added to the back-fill and only then were individual trees planted. All trees were afforded browse protection through the use of vexar tubes. Trees were irrigated several times through the summer which allowed for some survival. Trees that are lost to browsing or other factors will be replaced.
This season we learned, as much as anything, that we are coming close to doing the right thing, or better, the right things. The pity is, of course, that we have to do it at all. Which means that our aspirations, prosaic as it might sound, should resemble those of a good dentist. His or her greatest success would mean no more patients that need them. Good preventative practices would put an end to their business. Nothing would please us more than to be done with the need for salmon enhancement. The work is exhilarating, but it is also hard, cold and complex and rarely produces quick returns or clear and unmitigated successes. It is also a hell of a responsibility, this effort to save another species. Our many-faceted program must be responsive to a number of factors that increases with the increase of our knowledge of the system. This program seems to have developed to the point where it entails the capacity to maintain salmon stocks for a while. A healthy natural system would do it ever so much better. No combination of human effort and intervention can begin to equal the bounty that a healthy natural system produces - to wit, the hatcheries which for decades have been pumping vast numbers of artificially propagated baby salmon into our rivers and the ocean while overall salmon numbers continued to decline. Another factor is that we, the people that make up our work force, are no more nor less fallible than anyone else. Several of us are getting older. The age class of the average restorationist, dare I imply, approaches that which might be higher than is optimum for competence. (The younger amongst us will take issue with this inference, no doubt.) Humans, at any age, err. The survival of a species should not, ideally, be dependent upon the intervention of another species, one that is no less prone to mistakes than bears, let's say, or raccoons, and much more subject to foolish pride. Nor should it have to depend, as it seems to, upon such convoluted, complicated and essentially unsubtle techniques as those we have at our disposal. We may be able to say one thing for sure about our work without sounding foolish or vain. While the jumble of projects and surveys and applications of enhancement technologies that we undertake may, in the long run, be only one factor in what keeps the salmon alive, it has at least kept alive the link between people and salmon. And in the process of stumbling around trying to help, occasionally with good effect, we will have added considerably to the body of knowledge about our watershed and our fish that will be needed to preserve both the salmon, when they recover, and ourselves through ages to come. All this being said, our work has, combined with many other factors, created the potential for salmon recovery. We have made a serious effort to deal positively with as many of the factors limiting salmon productivity as we have been able to discern and been able to influence. The continued limits to commercial and sport fishing and the decline of traditional Mattole nighttime fishing has been a critical factor. We owe all the fishers our gratitude for their sacrifice. Mattole landowners, too, should be largely congratulated in so far as the growing concern for the health of our watershed has led to considerable forbearance and a new level of concern for our impacts on the system. While there are still many problems related to timber harvest, road building, subdivision and water diversions, we have come a long way in 20 years. It is revealed in the increase in vegetation throughout the valley and especially near the headwaters. The fact that we have managed to hold onto some of our old forests, especially where they protect prime salmon spawning and rearing habitat, is of inestimable importance. There is much farther to go, of course, but the will to get there is still strong. What stands in our way now, more than any other factor, are the Gods, if one can be so bold as to give shape, even so amorphous, to the huge forces afoot in the natural world. The vast El Niño approaching the Pacific Coast could unleash powers far beyond our ability to predict, let alone influence. If the weather was ever in the least way predictable, or perhaps it is better to say, dependable, it seems less so now. Rain at the right times in the right amounts is a great blessing for the salmon and for the world at large - at the wrong time and in the wrong amounts, we can all be left clinging desperately to creation by our fins or fingertips. Lack of rain can have the same effect. For survival, then, of the people and the salmon, let us all walk lightly and pray, brothers and sisters, pray. |
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