2018 study: most wild and hatchery fish becoming smaller and younger

[feelin swell]

A good read for anyone interested in what's going on out there:

2018 study looks at 4 decades of data and discusses leading hypothesized causes of salmon age-size changes. Have a look at what it has to say about the possibility that the increased number killer whales may have something to do with it over the past 40 years.

Also read how the age-size reduction may also have a compounding effect on the overall health of runs. In other words having the largest fish return to rivers instead of smaller ones may be very important. It appears to be an overlooked and poorly understood factor that may be critical to run survival.

https://onlinelibrary.wiley.com/doi/full/10.1111/faf.12272

4.3 Potential causes of observed changes
The reported changes in the size and age distribution of Chinook salmon populations across the Northeast Pacific could be responses to a variety of factors. Commonly hypothesized causes of change in salmon age‐size structure include (i) size‐selective harvest, (ii) environmental change such as changes in temperature regimes or ocean productivity that affect growth and mortality rates, and (iii) impacts of hatchery practices and increased competition for food (including non‐Chinook hatchery populations). A previously overlooked hypothesis attributes the observed changes to (iv) predation by marine mammals, especially a growing number of resident killer whales and their size‐selective predation on Chinook salmon (Chasco, Kaplan, Thomas, Acevedo‐Gutiérrez, Noren, Ford, & Marshall, 2017; Chasco, Kaplan, Thomas, Acevedo‐Gutiérrez, Noren, Ford, & Shelton, 2017). In the following, we present these hypotheses in detail and discuss their qualitative consistency with the findings reported in this paper. A summary of data relevant for evaluating these hypotheses at a broad geographic scale is provided in Figure 8.

4.3.5 Natural mortality

"Resident killer whales, on the other hand, selectively prey upon Chinook salmon, particularly the oldest and largest individuals (Ford et al., 1998; Hanson et al., 2010; Herman et al., 2005). About 90% of Chinook salmon eaten by residents are 4–6 years old (Ford & Ellis, 2006), and the abundance of resident killer whales has continuously increased since the 1970s (Matkin, Ward Testa, Ellis, & Saulitis, 2014; Ward et al., 2016). Currently, the total number of resident killer whales in the Northeast Pacific Ocean is estimated to be at least 2300 individuals (Muto et al., 2017), with many populations increasing 2–3× over the last 40 years.......
Bioenergetics calculations suggest that the residents currently inhabiting the coastal waters between northern California and southern Alaska (not including those along the Aleutian Islands and in the Bering Sea) consumed roughly 104 metric tons of Chinook salmon in 2015, which is ~70% of the total marine mammal consumption by weight (Chasco, Kaplan, Thomas, Acevedo‐Gutiérrez, Noren, Ford, & Shelton, 2017). This is equivalent to an annual consumption of about 2.3 million adult‐sized Chinook salmon, and similar to the recent annual commercial catch in the North Pacific Ocean (~2 million Chinook salmon, Irvine et al., 2009). While the relative contributions of harvest and natural predation vary by population and region, total coast‐wide mortality of Chinook salmon has increased over time despite reductions in fishery harvest. Chinook salmon are exposed to predation by resident killer whales along the coast, and exposure to predation during ocean residence depends on population‐specific ocean distributions and migration patterns (Larson et al., 2013; Weitkamp, 2010). Predation intensity is likely highest for coastal populations from Washington, British Columbia and south‐eastern Alaska, somewhat uncertain for populations in western Alaska, and lowest for populations that do not exhibit the long coastal migrations such as those from California and southern Oregon, as well as some Puget Sound populations. This spatial pattern of exposure to predation is generally coherent with the observed patterns in the declining size of older Chinook salmon across the Pacific coast (Figures 7 and S4) and warrants more examination of the potential of increased predation for contributing to the changing demographic characteristics we have documented in this study.

 

[fish brain]

I am a farmer, For as long as humans have been breeding things - From cows to Broccoli. Only use the biggest / best tasting stock is kept for reproduction. The current / past hatchery technique of mixing everything together in big containers has been a huge mistake, and I don't know why it hasn't been called into question. Maybe it has been and I just haven't heard. What should happen is large salmon are mated with larger salmon. medium sized females, are bred to males of the smallest of the large salmon, and the small salmon are bear food. Mixing the stocks will only lead to medium size fish returning. I believe this is what we are seeing now. Too bad fish biologists aren't farmers.

 

[feelin swell]

I am a farmer, For as long as humans have been breeding things - From cows to Broccoli. Only use the biggest / best tasting stock is kept for reproduction. The current / past hatchery technique of mixing everything together in big containers has been a huge mistake, and I don't know why it hasn't been called into question. Maybe it has been and I just haven't heard. What should happen is large salmon are mated with larger salmon. medium sized females, are bred to males of the smallest of the large salmon, and the small salmon are bear food. Mixing the stocks will only lead to medium size fish returning. I believe this is what we are seeing now. Too bad fish biologists aren't farmers.

You gotta wonder about the thinking behind releasing fry and smolts that have lived in a tank for months without any environmental stimulus to prepare them for the gauntlet they are expected to survive. Better to invest in long term solutions like river and stream restoration and protection. Look at what's happened to the Oregon and California Chinook runs... basically huge reductions in numbers from the big river systems like the Sacramento River and its tributaries. If you look at those rivers on goggle earth you can see one reason why. Loss of natural habitat. Annihilation of riverside and streamside vegetation like trees, shrubs and the natural environment along the banks of these watersheds. Trees and vegetation hold insects which young fish eat and provide cover from predators. They hold in cool pools. Returning fish as well. A significant number are cultivated right to the stream banks. Some runs from certain rivers are now extinct. In BC we treat our rivers, streams and creeks like extensions of our storm drainage and sewer systems. We have been degrading one stream at a time over many years. We can reverse that trend one stream at a time. We need volunteer organizations to reverse that trend. We need responsible citizens who are willing to adopt a stream in their neighbourhoods. Governments are not going to do much on the ground where it counts. But they can step up and do something to protect these streams. Enact sensible laws and regulations that protect habitat on private and public land. Laws that allow reasonable restoration access. Some funding for volunteer work and tax incentives for landowners who grant access and participate. Adopt a BC stream program so to speak. It would be nice if the feds could get together with the BC government and do something beneficial on the ground where it counts before it's too late.

 

[bigbruce]

You gotta wonder about the thinking behind releasing fry and smolts that have lived in a tank for months without any environmental stimulus to prepare them for the gauntlet they are expected to survive. Better to invest in long term solutions like river and stream restoration and protection. Look at what's happened to the Oregon and California Chinook runs... basically huge reductions in numbers from the big river systems like the Sacramento River and its tributaries. If you look at those rivers on goggle earth you can see one reason why. Loss of natural habitat. Annihilation of riverside and streamside vegetation like trees, shrubs and the natural environment along the banks of these watersheds. Trees and vegetation hold insects which young fish eat and provide cover from predators. They hold in cool pools. Returning fish as well. A significant number are cultivated right to the stream banks. Some runs from certain rivers are now extinct. In BC we treat our rivers, streams and creeks like extensions of our storm drainage and sewer systems. We have been degrading one stream at a time over many years. We can reverse that trend one stream at a time. We need volunteer organizations to reverse that trend. We need responsible citizens who are willing to adopt a stream in their neighbourhoods. Governments are not going to do much on the ground where it counts. But they can step up and do something to protect these streams. Enact sensible laws and regulations that protect habitat on private and public land. Laws that allow reasonable restoration access. Some funding for volunteer work and tax incentives for landowners who grant access and participate. Adopt a BC stream program so to speak. It would be nice if the feds could get together with the BC government and do something beneficial on the ground where it counts before it's too late.

You make it sound as if nothing is being done in this regard. The volunteer group I belong to are looking after 9 streams between Union Bay and Fanny Bay on Vancouver Island. We also operate a volunteer hatchery that raises and releases a DFO regulated number of coho and chum as well as providing space for fry that we salvage from the creeks we look after before they dry up due to a lack of water in the late Spring. These fish are released back into the creeks in the Fall when the creeks start to flow again. Then there's the 5000 or so trees we pot each year for or own stream keeping use as well as for distribution to other Vancouver Island stream keeping organizations.
So which volunteer stream keeping organization are you involved with???

 

[california]

I am a farmer, For as long as humans have been breeding things - From cows to Broccoli. Only use the biggest / best tasting stock is kept for reproduction. The current / past hatchery technique of mixing everything together in big containers has been a huge mistake, and I don't know why it hasn't been called into question. Maybe it has been and I just haven't heard. What should happen is large salmon are mated with larger salmon. medium sized females, are bred to males of the smallest of the large salmon, and the small salmon are bear food. Mixing the stocks will only lead to medium size fish returning. I believe this is what we are seeing now. Too bad fish biologists aren't farmers.

Salmon are NOT domestic farm animals. Even hatchery ones spend most of their lives living in the wild, not in a field or barn with only one purpose, producing meat. They are subject to the natural selection pressures, and making them bigger is not as simple as picking the largest ones. Hatchery production completely bypasses the natural selection the young salmon experience in the river, and again cuts natural selection out in competing for the best spawning areas and mates. It also completely cuts out an important part of the gene pool in naturally spawning populations of Chinook and Coho. Jacks are not stunted salmon, in fact they are just the opposite, salmon species have alternate life history possibilities based on how fast they grow when young. Jacks actually do very well, and are large enough to deploy an alternative life history strategy of returning early, thus avoiding predation and disease for 2 years, and employing "satellite" male breeding strategies. It is quite possible our cutting out the genetic contribution of these small salmon could be contributing to the decreased overall size. The fact is we really have NO IDEA what long term deleterious effects we are propagating by eliminating important selection pressures at the beginning and end of the salmons life cycle. It is NOTHING like selecting characteristics for pampered farm animals, and domestic animal production techniques are not appropriate. .

 

[feelin swell]

Well you've got the bragging rights on me. My hat is off to those who are doing such work. Dispite such efforts the rate of human encroachment on fish habitat is increasing. We need better environmental protection laws and enforcement and much more rehabilitation funding. Yes I was involved with restoring a stream near Lake Cowichan many years ago. We removed large woody debris dams that had blocked that stream for many years. When the November rains came we witnessed many coho swim up that stream for the first time in 75 years. What a great feeling. When I retire and have less work obligations I will likely do such volunteer work again.

 

[GLG]

Advancing mate choice studies in salmonids

Abstract
Mate choice in most organisms is not random, but determined by a suite of interacting traits and environmental factors. While the selective pressures underlying differences in mate choice between species, populations, individuals and even within individuals has been gaining interest, there still remains unexplained variation in mate preferences especially in non-model systems. Despite being of social, environmental and economic importance there is comparatively little known about how salmonids and other tetraploids make mate choice decisions in the wild and the resultant reproductive success (i.e. the number of offspring which survive to sexual maturity). Resolving questions related to salmonid mate choice is of particular importance given that humans have been supplementing salmon populations through aquaculture for decades. Despite these efforts, hatchery produced fish have lower reproductive success relative to their wild counterparts and salmon populations are declining. Most studies on mate choice and reproductive success in salmonids focus on body size and major histocompatibility complex based choice. However, mate choice can also be affected by other factors including other genetic factors, predation risk and social environment. Here, we (a) synthesize what is presently known about mate choice and reproductive success in salmonids, (b) identify gaps in knowledge and areas where there is a lack of consensus in results, and (c) suggest interdisciplinary ways of advancing our understanding of mate choice in salmonids and other polyploids.

https://link.springer.com/article/10.1007/s11160-019-09551-5

 

[fish brain]

You gotta wonder about the thinking behind releasing fry and smolts that have lived in a tank for months without any environmental stimulus to prepare them for the gauntlet they are expected to survive. Better to invest in long term solutions like river and stream restoration and protection. Look at what's happened to the Oregon and California Chinook runs... basically huge reductions in numbers from the big river systems like the Sacramento River and its tributaries. If you look at those rivers on goggle earth you can see one reason why. Loss of natural habitat. Annihilation of riverside and streamside vegetation like trees, shrubs and the natural environment along the banks of these watersheds. Trees and vegetation hold insects which young fish eat and provide cover from predators. They hold in cool pools. Returning fish as well. A significant number are cultivated right to the stream banks. Some runs from certain rivers are now extinct. In BC we treat our rivers, streams and creeks like extensions of our storm drainage and sewer systems. We have been degrading one stream at a time over many years. We can reverse that trend one stream at a time. We need volunteer organizations to reverse that trend. We need responsible citizens who are willing to adopt a stream in their neighbourhoods. Governments are not going to do much on the ground where it counts. But they can step up and do something to protect these streams. Enact sensible laws and regulations that protect habitat on private and public land. Laws that allow reasonable restoration access. Some funding for volunteer work and tax incentives for landowners who grant access and participate. Adopt a BC stream program so to speak. It would be nice if the feds could get together with the BC government and do something beneficial on the ground where it counts before it's too late.

I totally agree that habitat restoration is the key to fixing declining salmon stocks. I am just trying to say that, since we have degraded theses systems so badly that we need hatcheries, why not try to do some selecting for size or other desirable traits instead of just mixing things higgly piggly. If we are going to intervene in the process, we should at least try to be strategic about it.

 

[feelin swell]

You make it sound as if nothing is being done in this regard. The volunteer group I belong to are looking after 9 streams between Union Bay and Fanny Bay on Vancouver Island. We also operate a volunteer hatchery that raises and releases a DFO regulated number of coho and chum as well as providing space for fry that we salvage from the creeks we look after before they dry up due to a lack of water in the late Spring. These fish are released back into the creeks in the Fall when the creeks start to flow again. Then there's the 5000 or so trees we pot each year for or own stream keeping use as well as for distribution to other Vancouver Island stream keeping organizations.
So which volunteer stream keeping organization are you involved with???

I apologize for not mentioning all the volunteer work that has and is taking place by volunteers like yourself. Personally I guess I'm at the point in time where I have to ask myself if I can find the time to do a bit of fishing, then I have to ask myself can I find some time to join a volunteer group to help make a difference. IMO the level of stream protection laws, surveys, restoration work, and funding needs to be stepped up big time and become a government, fishing sector, and individual priority if we are ever going reverse the current declines. It can't just be about fishing restrictions. For me I will be looking into what I can do to help make a difference now and not wait till I have more time.

 

[chris73]

You gotta wonder about the thinking behind releasing fry and smolts that have lived in a tank for months without any environmental stimulus to prepare them for the gauntlet they are expected to survive. Better to invest in long term solutions like river and stream restoration and protection. Look at what's happened to the Oregon and California Chinook runs... basically huge reductions in numbers from the big river systems like the Sacramento River and its tributaries. If you look at those rivers on goggle earth you can see one reason why. Loss of natural habitat. Annihilation of riverside and streamside vegetation like trees, shrubs and the natural environment along the banks of these watersheds. Trees and vegetation hold insects which young fish eat and provide cover from predators. They hold in cool pools. Returning fish as well. A significant number are cultivated right to the stream banks. Some runs from certain rivers are now extinct. In BC we treat our rivers, streams and creeks like extensions of our storm drainage and sewer systems. We have been degrading one stream at a time over many years. We can reverse that trend one stream at a time. We need volunteer organizations to reverse that trend. We need responsible citizens who are willing to adopt a stream in their neighbourhoods. Governments are not going to do much on the ground where it counts. But they can step up and do something to protect these streams. Enact sensible laws and regulations that protect habitat on private and public land. Laws that allow reasonable restoration access. Some funding for volunteer work and tax incentives for landowners who grant access and participate. Adopt a BC stream program so to speak. It would be nice if the feds could get together with the BC government and do something beneficial on the ground where it counts before it's too late.

As long as we have this almost out of control population growth along our coastal streams I can't see how we will even hold our ground for the environment and fish habitat. The important but slow and small scale improvements here and there are vastly outpaced by new developments sealing new surfaces, piping stormwater, increasing water demand and producing sewage effluent. You plant 100 trees while 1,000 are cut down. Water flows downhill so where do you propose wastewater generated by hundreds of new subdivisions will go? It will end up in streams, groundwater and eventually in the ocean. Every person you add will take away room and habitat for fish and other life. I would be surprised if you can, even with all-out funding, mitigate more than 25% of the actual impact of population growth. You can fudge somewhat with artificial help like hatcheries but you can't have both: people and wild.

 

[Fishmyster]

As long as we have this almost out of control population growth along our coastal streams I can't see how we will even hold our ground for the environment and fish habitat. The important but slow and small scale improvements here and there are vastly outpaced by new developments sealing new surfaces, piping stormwater, increasing water demand and producing sewage effluent. You plant 100 trees while 1,000 are cut down. Water flows downhill so where do you propose wastewater generated by hundreds of new subdivisions will go? It will end up in streams, groundwater and eventually in the ocean. Every person you add will take away room and habitat for fish and other life. I would be surprised if you can, even with all-out funding, mitigate more than 25% of the actual impact of population growth. You can fudge somewhat with artificial help like hatcheries but you can't have both: people and wild.

There are streams in Clayquot sound with absolutely none of the urban or logging impacts you mention and have far less fish productivity by magnitude then the streams in the CRD. How does your prospective fit in there?

 

[Fishmyster]

If I was to hazard a guess it would be a lack of ability to absorb calcium from the water has caused smaller fish. There is a lot more to know in how chemistry effects ecology but it doesn't get much attention here. Another factor influencing could be a natural mechanism triggering the fish to reproduce asap during low abundance eras. I don't believe for even a moment that this salmon depression hasn't happened many times long before modern fishing influences. Considering the world has gone thru mass extinctions in the past before humans had the chance to ruin it all to see a depressed productivity era like now isn't so alarming.

 

[feelin swell]

There are streams in Clayquot sound with absolutely none of the urban or logging impacts you mention and have far less fish productivity by magnitude then the streams in the CRD. How does your prospective fit in there?

I think most people would agree that our former pristine rivers and streams were more productive than they are today and that proximity to human activity has a negative impact on fish. However in the case of Clayquot vs CRD, that's a question for a fish biologist. There are likely many complex factors. What you point out is a good thing in that streams in proximity to urban areas can be productive and therefore worth the effort to protect/restore them.

 

[Fishmyster]

I think most people would agree that our former pristine rivers and streams were more productive than they are today and that proximity to human activity has a negative impact on fish. However in the case of Clayquot vs CRD, that's a question for a fish biologist. There are likely many complex factors. What you point out is a good thing in that streams in proximity to urban areas can be productive and therefore worth the effort to protect/restore them.

Yes there are likely many complex factors but if we compare waterways with or without all the human encroachment factors we can eliminate some of the complexity and likeliness out of it.

My question of Clayquot vs CRD is for a water quality technician. I believe Chris73 is one of those. He is directing the blame of depressed productivity at urbanization but when compared to streams without those effects it then makes chemistry the next probable factor worth looking at. The field facts do not match the conclusion of urbanization being the such a major factor.

 

[chris73]

It is tough to speculate on what might have occurred on some streams without having actual data, and at that long term data. I can only speak to streams that I have data for and there the trend is clear - pristine or less impacted streams are in much better shape than urban streams in terms of a healthy and stable ecosystem. It doesn't mean that a pristine stream is necessarily more productive but has a balanced productivity based on a natural input of nutrients.

 

[Fishmyster]

It is tough to speculate on what might have occurred on some streams without having actual data, and at that long term data. I can only speak to streams that I have data for and there the trend is clear - pristine or less impacted streams are in much better shape than urban streams in terms of a healthy and stable ecosystem. It doesn't mean that a pristine stream is necessarily more productive but has a balanced productivity based on a natural input of nutrients.

Thank you Chris. That make a lot of sense.

I know it is tough to speculate on other areas where you have no information. I have provided some video information for the Cous, China creeks and Campbell river area. If you get a chance can you look at the videos. I would like your thoughts on why the Campbell river would have so much less invertebrate diversity or biomass than the other streams. The island area habitat looks pristine across from the powerhouse yet had very little life. Both Harland and myself were surprised how few bugs there was. I caught my first steelhead there in 1979ish. Got in sh#t for it too when I brought it back to the gun range where my father was at a shooting event. Wild of course! Anyways back then the bottom was blanked in large gravel cased caddis. Any ideas why now it would be so dead of life. The stream structure is pretty much the same as it was in the late 70's so it's not instability of stream bed that has washed the ecology away. Last time I checked March 13 2016 during very high discharge the Campbell alkalinity was 25ppm pH6.9 Quinsam was alk 28ppm pH6.9. Since then I have been noticing a gradual rise in other streams alkalinity so most probably is the same slight increase there. There must be something different in the water? Alkalinity in both Couse and China is similar to the Campbell river streams. How does Campbell river invertes compare to CRD stream invertes?

So if you could apply your expertise in water quality to the limited but factual information I provided on video what would you speculate the reason for so few invertes in the Campbell river this winter then say the Couse or China creeks? Just take your wildest guess. Your opinion would be appreciated.

 

[Fishmyster]

I know my last post is a little off the original topic but maybe not really.

 

[agentaqua]

Genetic analysis reveals differences in mate choice between wild and hatchery coho salmon

NEWPORT, Ore. – A new study of the genetic profiles of wild and hatchery coho salmon demonstrates important distinctions in how the two types of fish form mating pairs. These findings by Oregon State University researchers provide new insight into subtle differences between wild and hatchery...

today.oregonstate.edu

Differences in Mate Pairings of Hatchery- and Natural-Origin Coho Salmon Inferred from Offspring Genotypes

Synopsis. Captive breeding can affect how sexual selection acts on subsequent generations. One context where this is important is in fish hatcheries. In ma

academic.oup.com

 

[Bryan Allen]

This is a necessary discussion... But lets not forget the basic question, What would you prefer in urbanized streams ? Hatchery fish ?? Or NO fish? Think about it.

 

[wildmanyeah]

This is a necessary discussion... But lets not forget the basic question, What would you prefer in urbanized streams ? Hatchery fish ?? Or NO fish? Think about it.

load it full of hatchery chum and bring back the life!