What do Spring Salmon Eat?

[carpeweekend]

Those of us who have been providing samples received an e-mail with a detailed analysis of the UVIC study trying to answer this question.
A little tough slogging through all of the scientific jargon but a great overview of the UVIC study that many of us have been supporting through sending the stomachs along with species, sex, and size of salmon caught last year.

Some of the results are a little surprising. I really thought that most of the salmon in my area (Sidney) feed primarily on needlefish but herring were the predominant prey species in all areas although it clearly changes over the course of the year. Here are the key results:

• Key Results o Pacific Herring are by far the most important prey for both Chinook and Coho Salmon. Young of the year herring enter the diet in June. Juvenile herring (in their first two years of life) are important throughout the year; older, larger herring are important in spring and summer.
• o Northern Anchovy are important in Chinook diets in the Southern Strait of Georgia but not elsewhere.
• o Sand Lance are important in diets in the Southern Gulf Islands, Haro Strait, and Juan de Fuca (SGI/Haro/JDF). They are most important in spring and early summer.
• o Invertebrate prey are rare in Chinook diets but more common in SGI/Haro/JdF and West Coast VI than elsewhere.
• o Invertebrates (primarily crustacean plankton) are more important in Coho diets than Chinook diets.
• o Chinook Salmon specialize on Herring when they are present and eat other prey less often than expected by chance.
• o Chinook Salmon feeding on Lanternfish are more likely than expected by chance to also contain gadids (cod/pollock/hake) and squid, possibly due to deep feeding; Chinook feeding on Sand Lance are more likely to contain polychaete worms and bottom dwelling shrimp, possibly indicating benthic feeding.
• o There is a weak positive relationship between salmon size and prey length.

Thanks to Will Duguid and his team at UVIC.

 

[carpeweekend]

I also wanted to post this from his e-mail.

1. We are pleased to announce we have received funding through the Pacific Salmon Foundation Salish Sea Marine Survival Project to continue a full program in the coming year.
2. In order to make sure we reach our seasonal and regional sample collection targets we are looking to recruit volunteer regional coordinators who can communicate with other fishers and if necessary visit cleaning stations to complement sample numbers when needed. If you are interested or know someone who would be please respond to this email or juaneslabmanager@gmail.com.
   
3. We will be holding our 2018 draw for an Islander Reel this month. Thanks to the continued generosity of Islander Reels all stomachs with complete data submitted in 2019 will also count as entries in a draw for an MR2LA in February of 2020.
   
4. We struggle to get enough samples in winter.... If you are a cold weather angler we really hope you (and everyone else you can recruit) has fantastic fishing over the coming couple of months! Please submit all of the winter samples that you can!

 

[Whitebuck]

Great post!
Good to see how important herring are as a food source for our salmon.

 

[Slabbedout]

Is this similar to the head recovery program ? Where can we drop off samples ? Also could i freezes samples and drop off a bunch, since I normally just clean fish once I get home if I fish locally .

 

[Pineapple Express]

• o Chinook Salmon feeding on Lanternfish are more likely than expected by chance to also contain gadids (cod/pollock/hake) and squid, possibly due to deep feeding; Chinook feeding on Sand Lance are more likely to contain polychaete worms and bottom dwelling shrimp, possibly indicating benthic feeding.

Awesome post! I didn't know that this study was going on.

I wasn't familiar with the term "benthic feeding" so I looked it up. The benthic zone is the interface zone between the bottom of the water column and the top of the seafloor, so benthic feeding is feeding activity in this interface zone.

 

[california]

So the conclusions are herring are the most important feed, and early in the year young of the year herring are important. Seems reasonable to extrapolate that improving herring stocks, and particularly increasing the number of juvenile herring. might have a positive impact on salmon survival and growth? How could that be achieved? I wonder... How many millions of young herring are never produced and instead they are shipped to Japanese grocery stores for snacks? Just more evidence how F*%$ed up that fishery is.

 

[Bugs]

Thanks for this thread @carpeweekend. I actually first floated the idea for this project on this forum a couple of years ago

https://www.sportfishingbc.com/foru...on-diet-monitoring-program.64885/#post-812197

We are excited by how this program has worked out, and we are very hopeful that it can be continued indefinitely as a low cost way of monitoring the health of the ecosystem that supports our fish.

To answer @Slabbedout we do have depots where stomachs can be dropped off (listed below). Unfortunately they cannot be dropped in the head freezers... we looked into this but these samples get defrosted and this would cause problems.

If anyone is interested in this program further please PM me your email address or email us (juaneslabmanager@gmail.com). We will add you to the email list and send you the report which includes instructions and printable data cards. Thanks to everyone who is supporting this work!

Samples can be dropped off in freezers at Island Outfitters (Victoria), Home Hardware (Sidney), Harbour Chandler (Nanaimo), Tyee Marine (Campbell River), Pacific Net and Twine (Parksville), Bon Chovy Charters (Granville Island), Stillwater Sports (Ladner), Pacific Angler (Vancouver), Bamfield Mercantile and Marine (Bamfield), Ucluelet Aquarium (Ucluelet) and Eagle Eye Outfitters (Sooke). If these depots are not convenient, alternative arrangements can be made to pick up or drop off samples on a case by case basis. Please contact juaneslabmanger@gmail.com

When dropping off samples please ensure that you talk to staff to ensure your sample is put in the right place, not all staff may be familiar with the program.
Ziploc bags and waterproof data cards are available in the freezer totes at most locations, waterproof data cards can also be mailed on request and non-waterproof cards can be printed

 

[Bugs]

Another comment folks.. if you want to start freezing your stomachs right now (looks like a couple of calm, if cold, days coming) here is the key info to record for each fish:
Catch location
Species
Date
Fork Length
Clipped or Not
Freeze the whole gut (stomach and intestine)... And please send us samples whether they look full or not...

if you don't have our fancy data cards write the data in pencil on scrap paper.

You can follow us on facebook here: https://www.facebook.com/Southern-BC-Adult-Salmon-Diet-Program-493763831003993/?ref=bookmarks

 

[silversands]

I sometimes find herring sized Shiner Perch in Chinook in the Georgia Strait...not listed on that chart...just thought I would mention it.

 

[Bugs]

I sometimes find herring sized Shiner Perch in Chinook in the Georgia Strait...not listed on that chart...just thought I would mention it.

We do see shiner sea perch in stomachs... particularly in Georgia Strait in winter. The attached graph is summary by season and region. We group shiners as "surfperch" because we cannot always confirm species even when we can confirm family (Embiotocidae). In reality the vast majority (if not all) of these are Shiner sea perch.

 

[wildmanyeah]

Cool Graph!! and great work you guys are doing

 

[el.Pereh]

Very cool study. Interesting that hootchies are so effective southern sog at times when squid are not in the mix

 

[wildmanyeah]

Very cool study. Interesting that hootchies are so effective southern sog at times when squid are not in the mix

I had someone say this to me when I was fishing in North ECVI, We only use spoons there are no squid here, Meanwhile I tubed out on a green splatter back hoochie.

Some of my local vancouver gear out fished by far the local ECVI gear that everyone recommended to me. Chartreuse lemon lime flaser worked excellent

 

[paguy]

Very cool study. Interesting that hootchies are so effective southern sog at times when squid are not in the mix

A lot of the hootchies aren't designed to imitate squid.

 

[Bugs]

I should clarify.. this graph is actually for fish prey only..... but fish are overwhelmingly dominant in these regions. Here is fish v inverts

 

[paguy]

Some of the hootchies are to imitate sand lance, Herring and anchovies.

 

[Ian wagner]

A lot of the hootchies aren't designed to imitate squid.

As a commercial fisherman that. Has caught thousands of Springs from Alaska to Vancouver I have never seen a squid in a springs stomach and believe me I have been studying what they are eating not saying they don't eat squid just not were I have fished I know in Barkley sound in June they are in close eating squid but offshore there not also a huge amount of spring mid Westcoast of Vancouver Island are plugged full of krill in the spring time

 

[Bugs]

Out of about 900 Chinook examined we have 32 which contain squid. This was in area 26 in June.
I know in a couple of recent years there have been periods when there were reports that a crazy abundance of squid in area 23 was being targeted by Chinook. One of the goals of this project in the long term is to detect events like these... and trends over time. The idea here is that instead of going out with a boat and trying to work out what is present in the food chain and if it has changed... we use the fish to do our sampling for us. When an ecosystem component disappears or something new shows up we should detect it.

 

[RODNREEL]

Interesting thread.
Thank you

 

[wildmanyeah]

I’ve had a few years now where the chinook I’ve caught in March and April in area 29 just off the north arm of the Fraser ( QA). That has had sicklebacks in their stomach. Seems to also be times around the same time the brown sludge that gets stick to your lines shows up.