The following is an ODFW memorandum from Mark Chilcote to various people though out ODFW. It shows with incredible candor the degree of introspect many of the biologists at ODFW have when assessing a programs success. This document does contain some graphs that do not display on this forum. Anyone wishing a full copy may send me an e-mail expressing his or her desire to obtain the original and I will comply. POS Clerk

This document last saved by “Peter Dratch” / ODFW / Peter.Dratch@state.or.us

MEMORANDUM
Oregon Department of Fish and Wildlife


Date: February 1, 2002
To: Bob Hooton, Ray Temple, Steve Williams, Ed Bowles

From: Mark Chilcote

Subject: Revised Survival Estimates for Clackamas Coho Wild Broodstock Program

Last month I circulated a draft of a memo concerning the smolt to adult survival of fish from the Clackamas wild broodstock rescue program. I was working with preliminary numbers at the time and there was concern that these numbers were not representative. The return of coho to the Clackamas is now 90%+ complete. Therefore, I have updated this memo with the new numbers and make some preliminary conclusions about the results. The details follow, however main points are:
1. The smolt to adult survival of "wild-type" hatchery fish was nearly 1/10 of the survival rate for wild smolts (97 and 98 brood year production).
2. Averaging the results of 5 brood years, the total return to the basin was not increased by using wild fish for hatchery broodstock. Just as many total fish would have been produced if there had been no hatchery program at all.
3. All the hard effort involved in collecting and raising these fish didn't pay off. These results have very serious implications for the use of hatchery programs to help restore lower Columbia River coho.
4. We need to find out why this occurred (if we can). If there is no corrective solution, then our tools to help restore LCR coho have been significantly reduced. We need to respond accordingly.

Assessment Details
As you are aware the returns of both wild and regular production hatchery coho to the Clackamas and Sandy basins this year have been very encouraging. However, lost in the good news is a very disappointing return for hatchery smolts derived from wild broodstock that were released into the Clackamas basin as part of the "rescue/recovery" program implemented in 1996.

This rescue program was instated in response to the extremely depressed returns observed during the late 1990s. Wild coho were obtained for hatchery broodstock in significant numbers for the 1997 to 1998 brood years. Smolts were raised and released into the Clackamas basin upstream of the smolt counting facilities in 1999 and 2000. Subsequently, the number of both hatchery and wild coho smolts that emigrated past NF Dam were estimated. Dividing the number of returning adult coho counted at NF Dam in 2000 and by these smolt estimates (1999 and 2000, respectively), it was possible to calculate and compare smolt to adult survivals for hatchery "rescue" fish and wild fish.

To my surprise, there was a very large difference between the two groups of fish. The survival rates for the hatchery "rescue" smolts were low; 0.7% for 1999 smolts and 2.2% for 2000 smolts. In contrast, survival rates for wild smolts in the same years were 6.6% and 15.3% (Table 1). Although, hatchery smolts normally do not survive quite as well as do wild smolts, the difference is generally much less. Indeed, for the "regular" hatchery coho smolts released into the Clackamas basin during these same years (from Eagle Creek Hatchery) the survival rates appear to have been in the range of 7% (very rough estimate).

In addition to these most recent years, during the 1980s, 3 brood years of hatchery coho smolts were released into the Clackamas basin that were also 100% offspring of wild parents. When I looked at the survival rate for these fish and compared them to the wild smolt survival during the same period, the survival for wild smolts was again much higher than for these hatchery smolts originating from wild parents. The survival rate for wild smolts during these 3 years ranged from 1.8% to 0.7%, whereas for these "wild-type" hatchery fish it ranged from 0.40 to 0.10 (Table 1).

Table 1.

Because fish from the most recent wild broodstock program (97 and 98 brood years) were intended to assist the rebuilding of the wild population, the fact that their survival rates were nearly 1/10 of the level observed for wild smolts is troubling. In particular, these differences are so great that they may cancel out any gains that accrue due to the egg to smolt survival rates in the hatchery environment which are normally 10 to 20 times greater than they are in the wild environment.

To evaluate this question further, I compared the average number of adult progeny produced per parent under the two production systems (hatchery and wild). Among the 5 brood years evaluated, the number of wild fish used as parents for the hatchery program ranged from 46 to 140 fish (Table 2). For wild fish the parental population ranged from 235 to 4,277. Across all brood years the hatchery program yielded an average of 3.85 progeny per parent whereas the wild program averaged 3.93 progeny per parent. On the face of these numbers, it appears that the wild system performed about the same as the hatchery. In other words, removing wild fish and running them through the hatchery system yielded no more adult offspring than if they had been left in the river.

However, a closer look at these data demonstrate that this generalization has its weakness. The average progeny to parent ratios are strongly effected by the results for the last brood year (1998). When annual progeny:parent ratios are compared, wild production is superior to hatchery production in only 2 of the 5 years. Moreover, in these two years there appear to have been

Table 2.

specific problems that effected egg to migrant smolt survival of hatchery coho. For the 1989 brood year, I understand there was an outbreak of IHN at the hatchery and this greatly reduced egg to smolt survival. For the 1998 brood year, although over 123,000 smolts were released, only 53,661 emigrated past NF Dam (Table 1). The fate of these missing smolts is unknown, but we know that they did not contribute to the adult return.

Examining this question further, I computed the number of smolts produced per spawner for the hatchery and wild environments. As expected, the hatchery environment was much more efficient in converting spawners to migrant smolts (although the poor results for the 1989 and 1998 brood years are evident in these data) (Table 2). But what I want to draw your attention to are the smolts per spawner estimates for the wild environment. Note that the highest value (107 smolts per spawner) occurred for the brood year that had the fewest spawners (235). This demonstrates that at lower spawner densities the egg to smolt survival was quite high - exactly what classic spawner-recruit models would predict. In fact, if one plots smolts per spawner in the wild environment versus total wild spawners (Figure 1), a logarithmic equation describes the relationship pretty well (R2 of 0.67). Obviously, no one should get overly excited about a

Figure 1.

recruitment relationship based upon 5 data points - but I believe it illustrates a very important point. When the spawner density begins to fall into the range that we might be concerned about the persistence of the population, we should expect egg to smolt survival to be at its highest (i.e., not many mouths to feed and essentially an unlimited habitat). Under such conditions, there will be little benefit to bringing some of the wild fish into the hatchery environment if the resulting hatchery smolts will have ocean survival rates that are 1/10 of those for wild smolts.

At the other extreme, the highest progeny:parent ratios hatchery fish relative to those for wild fish were obtained for the 1988 brood year, which was one of the highest wild escapements (4,277 fish) in recent times. Therefore, it would appear that the hatchery "rescue" concept works in the years you don't need it and fails in years that you potentially do.

As if this was not enough reason to be pretty skeptical about these type of hatchery programs, all indications are that hatchery fish, even from wild broodstocks, are not as successful as wild fish in producing viable offspring under natural conditions - at least based upon the recent analyses I have completed on steelhead populations as well as other sources.

In light of the information presented here, I have drafted some possible lines of questioning to determine if these results are reliable and have been correctly inferred from the available data. I also suggest some possible explanations for these results. In both instances I need help from people more familiar with these basins and hatchery programs. Therefore, it is my hope that the main function of this memo is to generate comment and discussion about the issue. These results have a significant bearing on the use of wild fish in hatchery programs for conservation purposes. I suggest a proactive response to search for solutions now, rather waiting until the next crisis occurs. In addition, these results may influence how we implement the hatchery supplementation portion of the LCR recovery plan.

Data Quality/Problems

Some of the sources of potential error that need scrutiny include: reliability of detecting wire in returning adult fish with present technique (wanding of un-anesthetized fish), errors in estimating smolt migrants because of temporal variations in spill at NF dam and the associated reduction in gear efficiency, and wild adult recruitment from smolt production in areas other than above NF dam. I am sure there are other estimating problem areas; hopefully with the help of others we can complete and critique a full list of them.

Cause of Reduced Survival

Assuming this problem is real and not an artifact of poor data or analyses, what can be the possible explanations and how might we correct them? Again, I provide some possible ideas with the hope that a longer list can be generated. What do we know about the timing of the smolt release? The Clackamas wild fish go in May and June - I assume the hatchery fish went earlier. Also what about other smolt quality questions such as size, disease exposure, and condition factors - are there any patterns? Is there some feature of predation that would effect these fish differently than regular production releases from Eagle Creek Hatchery or the wild fish? Is there anything about the size, sex ratio, or other measurable trait that suggests that the rescue fish have developed differently than the wild fish?

CC
King
Kostow
McPherson
Stickell
Otto
Bourne
Muck
Frazier
Doug Cramer (PGE)
Doug Olson (USFWS)
Doug Dysart (USFWS)
Page 5

Fish Division
PO Box 59, 2501 SW First Avenue
Portland, OR 97207
Phone (503) 872-5252 Fax (503) 872-5632

PC, What do you think of what they said??

Fishhead5

Interesting read, POS, and one that raises some serious questions about the broodstock program on the Clackamas river. I'd be most curious to see if similar studies on free-flowing rivers have the same results.

Pretty easy to see what went wrong. Once the eggs were taken and the fish were reared in a hatchery, they ceased to be wild. All fish with "wild" characteristics, (shy, territorial, afraid of fish feeders, not tolerant of handling or disease, etc.) died in the hatchery environment, and all of the fish with domestic characteristics (tolerant of crowded conditions and disease, not afraid of handlers or feeders, etc.) survived. These survivors were not as fit as hatchery broodstock smolts, however, as they likely had some residual wild tendencies that caused them to be more susceptible to the diseases and stresses in the hatchery environment and caused them not to grow as fast or as large. All else being equal, small hatchery fish do not survive as well as large hatchery fish. Larger fish are faster, so they can get away from predators easier. Larger fish can also handle more starvation time until they figure out how to eat without being fed. Usually that means they have to wash out into the ocean during a year of high productivity, where feed can be had just by opening their mouths. That's really why we got those fantastic returns this year - a combination of high spring flows and excellent ocean conditions.

This whole idea of wild fish rescue using hatcheries is flawed, what needs to be done to rescue the wild fish is provide them wild habitat, and provide enough escapement of spawners to fill that habitat. If the habitat is gone and we are never going to get it back, then what exactly is the point of saving "museum piece" wild fish who will never have a place to spawn anyway? Now if we are going to take a dam out then great, let's try to save the genetics of the indigenous populations. But if not, forget it and convert it into a hatchery river and start requiring wild fish release - and banning fishing techniques that cannot accomplish this - on rivers that still have some habitat.

What I read was a bunch of bureucratic (sp) gobelty gook. There were so many if's, and's or but's. None of it could be taken for fact. Get the "facts" and then work on a soultion.

Fishhead5

I've talked to several fisheries biologists about the wild broodstock programs and they've been very skeptical that these fish can reproduce better in a hatchery than in the river. It makes sense to me that they'd reproduce better in the river, after all they've had 10's of thousands of years to develope their reproductive stratagies. Are we humans so arrogant as to think we can do better in a few hundred? After all, we've done nothing but screw it up so far. The benefit of the wild broodstock, to me, seems to be that you don't have to worry about the hatchery fish damaging the wild fish gene pool through interbreeding. It allows a less dangerous hatchery fish program for anglers to be able to keep their catch than having broodstock from other basins. However, if the returns are low, maybe it's not worth the expense. Personally, I prefer to fish for wild steelhead over any other fish. For sport, the wild broodstock fish don't stack up. I'd prefer the fish be left in the river and money be diverted from the hatcheries to habitat restoration. Let the fish have sex au naturale!

does anyone know survival rates for snider creek steelhead or for the quinault's wild broodstock program? they seem to be kinda successful....

Thank you all for your replies both here and privately.

POS Clerk