Net pen coho

[Smalma]

Puget Sound resident coho much like their blackmouth cousins came from a mixture of delayed releases (net pens for coho), normal releases and wild fish. The contributions of those 3 groups vary a lot year to year. Bottom line the net pen/delayed fish tend to have a higher tendency to residualize than more normal timed smolts but are not the sole source of those resident fish. Even the south sound net pens are not necessarily the dominate producer of those resident coho.

Regarding typical coho return rates; one would assume that the net pens at Oak Harbor would have survival rates similar to the Skagit. Since 2005 the estimated return rates for the Skagit coho have been in the 10 to 12% 3 times in the last 16 years and below 10% 13 of those years. The other nearby system would be the Snohomish which until recently would often have return rates between 10 and 20% though those rates fell in 2013 and since have hovered around the 5% range.

curt

 

[Pink Nighty]

Puget Sound resident coho much like their blackmouth cousins came from a mixture of delayed releases (net pens for coho), normal releases and wild fish. The contributions of those 3 groups vary a lot year to year. Bottom line the net pen/delayed fish tend to have a higher tendency to residualize than more normal timed smolts but are not the sole source of those resident fish. Even the south sound net pens are not necessarily the dominate producer of those resident coho.

Regarding typical coho return rates; one would assume that the net pens at Oak Harbor would have survival rates similar to the Skagit. Since 2005 the estimated return rates for the Skagit coho have been in the 10 to 12% 3 times in the last 16 years and below 10% 13 of those years. The other nearby system would be the Snohomish which until recently would often have return rates between 10 and 20% though those rates fell in 2013 and since have hovered around the 5% range.

curt

Could the bumped up return rate be due to feeding them in the salt for 6 months? I would imagine a hefty chunk of the predation on skagit silvers happens within the first few months of saltwater rearing. Is it reasonable to assume wild fish return at 10-20% after 6 months of salt rearing?

 

[Smalma]

Pink Nighty-
Good question!

In the original posting on this thread, they were saying that fish were being transfer to the pens and are being held approximately 5 months prior to being released (late April/early May) which would be within the time frame that coho would be migrating to the salt. There is a potential that they could experience a higher return rate if while in the pen they had better growth than at the hatchery or river. That can be a bit of a mixed bag.

curt

 

[gpt]

ever go past a cattle feed lot?? that is what is under these net pen operations.

 

[Bagman]

ever go past a cattle feed lot?? that is what is under these net pen operations.

cow shit?

 

[gpt]

cow shit?

you got it half right. polluting every place they put them because they have to remain out of strong currents for their anchors to hold.

 

[Stonedfish]

One good thing about these types of coho net pens is they aren’t in continuous use. The fish are only in there for maybe five months or so before they are released. They are also native fish to the area and provide angling opportunities.
Commercial net pens operations are in continuous use and provide no angling opportunity unless they have an accidental release of a bunch of non native fish like what happened with Cooke.
SF

 

[East Coaster]

In addition to the other contributors to better returns mentioned above, is it logical that since the net pen-reared cohos are more likely to residualize, they will also benefit from lower mortality than ocean-going fish? Even the little reading I've done on the issues with the anadromous fish in your area points to ocean conditions as a common factor in poor returns (affecting salmon and steelhead). Seems that it would stand to reason that if a higher percentage of these pen-reared fish don't go to sea, the losses would be less, and thus the returns would be higher (%-wise). Just a thought......

 

[Wetswinger]

They say that 10% to 20% “return” in three years. Sounds like they go out to sea and then return.

This is from talking to the native fisherman over at Arcadia boat ramp. The Squaxin manage pens near Harstine Is. They say the Coho do show up there in the late summer, returning from all over the Sound. Squaxin Is., being at the terminus of all the deep So. Sounds fjords benefits all those areas for late Summer coho action. 75% of the Coho I've caught down in Budd Bay are clipped and assumed to be from the net pens at Squaxin. One tribal fisherman I talked to said he concentrates near where the pens are located, because it is the most productive site..

 

[Doublebluff]

I worked in the WDFW hatchery system in my youth. One of my weekend jobs was care of the net pens at Fox Island. I recall quite high mortality rates from disease in those pens. Hopefully they have that a little better figured out nowadays.

 

[BryanG]

This is from talking to the native fisherman over at Arcadia boat ramp. The Squaxin manage pens near Harstine Is. They say the Coho do show up there in the late summer, returning from all over the Sound. Squaxin Is., being at the terminus of all the deep So. Sounds fjords benefits all those areas for late Summer coho action. 75% of the Coho I've caught down in Budd Bay are clipped and assumed to be from the net pens at Squaxin. One tribal fisherman I talked to said he concentrates near where the pens are located, because it is the most productive site..

We just bought some land in Harstine. Looking to try to figure some things around there in the near future. Definitely somewhat of a steep learning curve! If anyone would like to chat further via PM, please reach out. Unfortunately, due to my very preliminary amount of knowledge, I don't have much intel to offer, other than to say that there are some nice fish in some of the lakes just off the island!

 

[gpt]

In addition to the other contributors to better returns mentioned above, is it logical that since the net pen-reared cohos are more likely to residualize, they will also benefit from lower mortality than ocean-going fish? Even the little reading I've done on the issues with the anadromous fish in your area points to ocean conditions as a common factor in poor returns (affecting salmon and steelhead). Seems that it would stand to reason that if a higher percentage of these pen-reared fish don't go to sea, the losses would be less, and thus the returns would be higher (%-wise). Just a thought......

'ocean conditions' is a polite way of saying 'we have little to no idea what is going on'.