Argulids- SRC vs salmon

[SaltyCutt]

Wondering if anyone knows why we don't see argulid infestation on our resident salmon? I have caught hundreds of resident coho and juvenile blackmouth and can't remember seeing very many if any argulids on them. The cutthroat on the other hand are carrying 12 to 30+ of the parasites each.

Although I tend to think of salmon as more open water fish and cutthroat more with shoreline, i catch many salmon feeding in the same tidal zones as cutthroat. Resident coho also spend a significant amount of time in Puget Sound after net pen release. Why no argulids?

SRC spend at least some time in streams spawning and in theory the freshwater should clean the parasites. I would think the amount of time between freshwater journeys and the time juvenile salmon are in the Sound would be similar in time frame. If both species are exposed to the same environment for the same amount of time, i would think we'd see similar parasitic infestation.

Is it as simple as cutthroat spending time in shallower, rockier, and possibly warmer zones? I've reached out to the Coastal Cutthroat Coalition as well and will post any insights they have.

-Steve

 

[Smalma]

At the coastal cutthroat symposium at Newport Oregon a couple years ago the species specific nature of argulids was a topic of discussion in one of the after hours beer sessions. Had to discuss this issue with WDFW and coastal cutthroat folks that have worked with the south sound cutthroat. The upshot was no one was exactly sure why the cutthroat attracted more parasites. That said most thought that the sedentary behavior at some tide stages; especially when holding in eel grass allowed the opportunity for the transfer of the parasite from the vegetation to the fish. The cutthroat seem to behave that way more often than say coho.

They did comment that the cutthroat in the late summer/fall make quick migrations into the small streams for a few days only to drop back to the salt - all well in advance to their spawning season. They were not sure whether the fish were seeking cooler water or ridding themselves of the parasites - maybe both?.

It was visiting with those folks and compare their observations with the south sound cutthroat and my own with the north sound fish was very interesting. Its that diversity in behaviors and biology that contribute to the mystic that drives us cutthroat advocates to spend the time we do chasing this critters.

Curt

 

[SaltyCutt]

You bring up a good point Curt, one that I hadn't observed until recently. Floating over eel grass beds in 10+ feet of water I was able to see cutthroat sitting stationary on the eel grass. It was fascinating and could definitely put them at a higher risk than the cruising coho.

 

[Smalma]

Some of the earliest radio tagging studies with sea-run cutthroat was with Hood Canal fish. They documented several fish that during the later part of a falling tide that retreated to the eel grass holding through the low slack and into the early flood without moving. Obviously this behavior likely varies depending the circumstances of the site.

Curt

 

[Jake]

One more reason to get rid of the damn fish farms.

 

[Smalma]

Jake -
The arguids infecting the cutthroat are not the sea lice that one reads about being associated with the net pens of the fish farms.

Curt

 

[Jake]

Jake -
The arguids infecting the cutthroat are not the sea lice that one reads about being associated with the net pens of the fish farms.

Curt

Smalma,

I’ve heard, anecdotal evidence being what it is, from a relative who worked at Cooke that the argulids are abundant. But I could be wrong.

 

[skyrise]

The Coastal Cutthroat group has posted several short paragraphs about this and other related topics with searuns. Look them up in Facebook. They post very interesting findings every now and again. Sadly almost all about south sound searuns but understandable considering the larger numbers down south and ease of working around small streams/ estuary compared to north sound & the size difference.

 

[Stonefish]

I think finding cooler water makes a lot of sense.
There are some saltwater areas that get extremely warm by mid summer.
I have a friend who lives near a cutthroat spawning creek in an area where the saltwater gets very warm. He describes the saltwater at this time of year as felling like bath water.....
He has observed cutts in the creek throughout the summer months, then they disappear as the weather cools and we get some rain.

In certain areas, some also may be following summer chum up creeks to munch on some eggs.
SF

 

[SaltyCutt]

Reply from Greg Shimek, Director of the Coastal Cutthroat Coalition:

As far as the Argulus is concerned it is Coastal Cutthroat Trout specific and only occurs on fish in the saltwater. No species of salmon, including pen raised Atlantic Salmon are affected . The infestations certainly seem to be increasing but at this time we have no answer why. With the data that anglers have submitted through our website we have an idea where and when the infestations are the worst and a paper is being published on this soon. It will be posted on the website when it is released. This certainly is something we are watching closely as the effects are unknown at this time but we believe large infestations can’t be healthy for the fish.

 

[Jake]

Reply from Greg Shimek, Director of the Coastal Cutthroat Coalition:

As far as the Argulus is concerned it is Coastal Cutthroat Trout specific and only occurs on fish in the saltwater. No species of salmon, including pen raised Atlantic Salmon are affected.

Well, I’ll be darned. Thanks for posting this, I love learning new things about this fishery!

 

[SaltyCutt]

Well, I’ll be darned. Thanks for posting this, I love learning new things about this fishery!

Same here, I did not expect that answer. Really interesting

 

[jaredoconnor]

Do they harm the fish in any way? I've seen people picking them off in YouTube videos, but I imagine removing them does some damage in itself.

 

[SaltyCutt]

Do they harm the fish in any way? I've seen people picking them off in YouTube videos, but I imagine removing them does some damage in itself.

I'm not sure, I've had two small ones attached to my hand after landing fish, and they detached with a little encouragement. They hadn't had time to really anchor though.