Striped Bass Regulatory Proposal: The Staff Report

[matt johnson]

Interesting observations.... If I recall my reading on Salmon from, admittedly non-scientific literature, that male Salmon return in larger numbers and at a wider variance in ages than females. Smaller males are called jacks and return earlier (in their second/third years) and in large numbers in order to supplement those of the older males. Thus, assuring enough males to guarantee mates for successful spawning. If my understanding is correct, wouldn't the 3 - 4 year return cited for typical Salmon be an overstatement of age or does typical mean an average (or some other measure)

Two year-olds, mostly jacks (males) and a few jills (females), typically make up only a small proportion of the spawning run for all four races of Chinook in the Valley. I have heard that two year-olds are commonly found in higher proportions in the Klamath Basin, but I don't have much experience with the Klamath....

Most of the Chinook age reconstruction in the Central Valley comes from coded wire tag recoveries. Coded wire tags are essentially a hatchery salmon's birth certificate. They age a salmon with certainty. Most of the coded wire tagged hatchery Chinook in the Central Valley come back at three to four years of age....

However, (there are few holes for round pegs in fisheries science!) the last two years there have been unusually high numbers of two year old salmon returning to the hatcheries. Go figure? This has been verified through coded wire tag analysis.

Age analysis of naturally produced Chinook in the Central Valley is currently in active data collection and analysis mode and is based on scale reading. I am unaware of any results so far....

[matt johnson]

I note in the Staff Report that no mention of predation on other listed species or canabalism by Salmon/Steelhead is included in the report. Yet, it does occur.

Predation is a constant in the life of a baby salmon. Ever wonder why a female salmon lays a few thousand eggs? If they stuck around to gaurd their young instead of dying, predation might be a lesser variable. The heat is on as soon as those fry emerge from the gravel!

Addressing Darian's point: Consider winter-run Chinook fry for a moment.... The entire fry population emerges smack in the middle of crazy numbers of big resident rainbows, rainbows that would likely have smolted and got the hell out to the ocean if livin' weren't so easy in a temperature controlled environment.... But who knows if the Sac rainbows even eat winter-run fry?? No one is looking at that. (So far swinging fry patterns on the Sac has not been as fruitful as it was for me on the Yuba, but I don't get out much these days...)

The cool thing about predation is it makes survivors. What really galls me about some predation studies out there is the fact that they are using (out of necessity) hatchery smolts to conduct their studies. It may be that hatchery and wild smolts behave completely differently when faced with predators in the delta environment???

Here is a likely scenario of what is being done in some studies: A group of flabby "meat missles" that have been living on pellets in a concrete ditch with zero exposure to predation are driven to some location in the delta. The fish are then put to sleep and surgically implanted with a plastic coated tag about the size of a seedless green grape. After coming out of the dope and resting in a tub for awhile, the fish are released and their progress through the delta is monitored. Do such studies offer an accurate representation of the behavior of wild juvenile salmonids when dealing with predation ??? Maybe they do maybe they don't???

Predation is a fact of life as soon as a fry emerges from the gravel. We have engineered the hydrology and physical structure of the delta so that predators have an advantage. That is the problem with predation . Matt

[bart]

They have done some radio tagging latl;y.I don't know the extent of it,but will be asking questions.

[Darian]

Matt,.... Thanks for the additional info. Your description of the situation with hatchery reared fish confirmed the way I thought it might actually be. I had no idea that the implant would be so large....

BTW, I've had some luck on the Feather on alevin patterns during January (if that's any help)....

[Darian]

Matt,.... If I understand correctly, The radio tags are implanted into hatchery reared fish which are then released in Old River. Stripers eat/digest the hatchery smolts, including the radio tag.

when Stripers pass their waste, what happens to the radio tag Is it expelled by the Bass to lay on the bottom Or, does it remain in the Striper

Thinking out loud here, it's not likely the latter as there would be such an accumulation of tags that it would eventually block the digestive system.... So, it has to be that there's a bunch of tags remaining on the bottom of the Delta. Otherwise, there'd be a bunch of stripers dying from Constipation.... Do the radio tags continue to transmit while down there If they still transmit, DFG must recognize this situation as the position of the transmitter would be static. Is DFG able to use the information generated or is it useless I'm really curious about this....

[Marty Gingras]

I've done a bunch of telemetry (adult Chinook; splittail; striped bass), my staff have done some recently (pikeminnow; striped bass; steelhead), and we understand what others are doing.

If I understand correctly, The radio tags are implanted into hatchery reared fish which are then released in Old River. Stripers eat/digest the hatchery smolts, including the radio tag.

Tagged fish are being released at a number of locations. No doubt striped bass sometimes eat tagged fish, but finding tagged fish in the stomach of striped bass (or any predator) is very uncommon. All told, critters that are reasonably big, act like predatory fish, are fast-moving, and sometimes quickly travel a long distance eat a varying and sometimes large fraction of tagged smolt-like salmonids.

As a related aside: Young salmonids implanted with coded-wire-tags --- or just the CWTs from such fish --- are relatively commonly found in the guts of pikeminnow harvested as part of the bounty program on the Columbia. The program has access to a lot of harvested pikeminnow. Application of CWTs is benign compared to application of acoustic or radio tags.

when Stripers pass their waste, what happens to the radio tag Is it expelled by the Bass to lay on the bottom Or, does it remain in the Striper

Whatever eats the tagged fish generally expels the tag after a period of time.

Do the radio tags continue to transmit while down there

They are usually acoustic tags. They transmit until their battery dies, which is generally relatively quickly (e.g., weeks to a month or so) for tags in little fish. Tags applied to the big fish around here (e.g., sturgeon) are often designed to transmit for years.

If they still transmit, DFG must recognize this situation as the position of the transmitter would be static. Is DFG able to use the information generated or is it useless

The researchers in all the studies I've been a part of and in local studies I've read about take this into account. Vogel does it really well.

[cyama]

From the report
"Although studies of striped bass predation show each of the listed species to constitute a relatively small part of the striped bass diet, and although the actual level of striped bass predation on these species is unknown and likely unknowable, the enormous volume of fish (up to 110 million pounds annually) consumed by striped bass and the widespread distribution of striped bass within the geographic range of the listed species indicate the impact of striped bass predation on the listed species could be substantial;"


Marty,

The report is admitting that predation of listed species is a small part of the diet of Striped bass and is basically unknown and unknowable. How can the DFG justify such a huge jump in the catchable limit of bass? You are going from 2 fish over 18" to up to 6 fish at 12". Twenty fish in some areas. Can these numbers be challenged? Is the DFG set on the regulation as written? In comparison this would be like raising the trout limit to 15 fish in some areas...

I must admit i am not an expert in the whole striped bass predation situation, but last year I remember that the situation in the Delta was that water could not be pumped down South due to conservation of the Delta Smelt. Over the past year huge amounts of water have been pumped down south, tons of smelt have been ground up and now the stripers are at fault? What happened is all I can say...


One other question

"the enormous volume of fish (up to 110 million pounds annually) consumed by striped bass and the widespread distribution of striped bass within the geographic range of the listed species indicate the impact of striped bass predation on the listed species could be substantial;"


Is the estimated 110 million pounds consumed by striped bass to include their diet while in the ocean? If so that number should be reduced substantially when discussing the predation in the Delta...

[Marty Gingras]

How can the DFG justify such a huge jump in the catchable limit of bass?

The Staff Report, including the references, describes the justification. The sort of paraphrase I could provide here wouldn't do it justice.

You are going from 2 fish over 18" to up to 6 fish at 12". Twenty fish in some areas. Can these numbers be challenged? Is the DFG set on the regulation as written?

The proposal we submitted to the Commission is just that. The Commission can accept, reject, or amend it. The Commission receives a lot of input from those who oppose proposed regulations, and --- by sending a FAX or email, in person at a meeting, or by making a phone call --- anyone can given input to the Commission challenging our proposal.

Over the past year huge amounts of water have been pumped down south, tons of smelt have been ground up and now the stripers are at fault?

Water operations cause indirect and direct adverse impacts on listed fish. The indirect impacts are notoriously hard to quantify and are no doubt important. The direct impacts (e.g., loss of entrained fish) are easier to quantify up to a point --- because of the massive amount of data developed at the salvage facilities --- and are no doubt important.

I am not a 'water apologist', but have to say this because it's true and will help the discussion: Water operations have changed a lot over the years and many people don't realize that relatively few (but important numbers to be sure) delta smelt and longfin smelt have been lost in recent years due to entrainment. For example: I believe less than 60 delta smelt were salvaged (that is, rescued rather than allowed to get to the pumps) this year, such that --- even loosely accounting for delta smelt too small to be salvaged and such --- probably more like less than 20 pounds of them have been lost into the CVP and SWP south-delta diversions this year.

The salvage information is here:

http://www.dfg.ca.gov/delta/apps/salvage/Default.aspx

Reports on salvage (and to an extent, 'loss') are here:

ftp://ftp.delta.dfg.ca.gov/salvage/A...age%20Reports/

Is the estimated 110 million pounds consumed by striped bass to include their diet while in the ocean? If so that number should be reduced substantially when discussing the predation in the Delta...

All the bioenergetics-based estimates of prior prey consumption we cite in the Staff Report are system-wide and w/o regard to prey species. That is, the estimates include prey taken in the ocean. It's that way because it was impossible to discern otherwise.

We recognize that only a fraction of what striped bass consume gets consumed in any particular region during any particular period.

The collective 'we' are working to develop methods to make region- and prey-species-specific estimates of what striped bass consume.

[Darian]

Marty,.... Could the low numbers of Smelt lost to entrainment at the pumps in recent years be due, at least in part, to their low population numbers overall (I'm assuming at my peril that nothing has been done to upgrade the salvage process at the pumps that would account for this)

[Jgoding]

Another thing thing on smelt.... aren't they pretty fragile and would probably disitengrate pretty easily anyway passing through the pumps? It would seem you would never know they were there as they pretty much melt like butter for the most part and you would be lucky to salvage any.

This whole situation kind of pisses me off but I will give Marty kudos for actively participating. My personal opinion is stripers are getting the short end of the stick on this proposal and we really need to look at habitat, water quality issues, and maybe even hatchery practices if we really want to save our beloved fisheries.

I know water interests are important as well, but goddamn, we're not the well-spring for SoCal or agribusiness that wants to grow water intense crops or crops solely for export in arid regions.... it's not sustainable and they need to realize that and get over it really quick or invest money in other resources/technologies to get freshwater elsewhere. I gather from what is spent on hiring lawyers etc... and court costs it couldv'e been done already. And the peripheral canal..... really..... the whole idea and how it's being pushed into a possible reality is just disgusting.