June 14-15, 2017 Slides
Michelle Workman, Mark Gard, Cesar Blanco, Mike Urkov, Shelly Hatleberg, Steve Tsao, Jeff Abrams, Towns Burgess, Jonathan Nelson, Dan Kratville, Jason Hassrick, Steve Zeug, Felipe Carrillo, Mike Berry, Bob Null, Sarah Gallagher, Matt Johnson, Brett Harvey, Mike Wright, Jim Peterson, Adam Duarte
Jim began the meeting by reviewing the Chinook Salmon base model. He then provided an example he worked on for Bull Trout conservation.
Jim reviewed the O. mykiss objectives and management actions from the previous phone call with the group. Jim asked if the group wanted to change any of the objective attributes. Michelle asked about the number of outmigrating juveniles or repeat spawners. Matt wanted to add smolt survival or something about smolt abundance. Jim asked if the group wanted to change any of the management scenarios/actions. Mark G. asked about floodplain rearing. Jonathan said they use the tributaries. Steve T. said the timing of floodplain is incorrect for steelhead. Michelle said they use the upper tributary floodplain habitat and that the Chinook model separates those habitats, so they could do that here. Jonathan said that they do use the habitat above Chico, but in the lower system where it is more channelized they don’t seem to use it. Mike B. mentioned that the hatchery steelhead program influences wild fish because they have to go into the hatchery, be handled, and then go on out. Jonathan said they don’t release non steelhead hatchery fish into anadromous waters; however, the fish that they do release don’t always leave. Michelle said she could envision a change in release strategy. Jonathan said there are 4 hatchery streams. Sarah mentioned that the release of fish above that get washed out into the streams and can compete with steelhead. Michelle mentioned Delta or cross-channel operations are a problem for them on the Mokelume. Matt wanted winter, spring, and summer to be listed for manipulate flow regimes.
Jonathan said the timing of runs is August through October which are the early running fish (both wild and hatchery). In October, fish run to Feather River. December – Feb is mostly hatchery and are the winter run. They all overlap or can overlap in spawning. November/early December to April is spawning. Spawning can occur as late as June, but it peaks in February. They have a protracted spawning season. Jason said estuarine habitat is potentially important for rearing. Mike B. said upstream of Clear Creek there are seasonal tributaries that have a lot of juveniles. Resident fish get first shot at those habitats but we don’t know if steelhead have access to these 50 miles of habitat. Mike B. mentioned increasing summer rearing habitat and connectivity through ephemeral streams.
Jim asked about the spatial grain. Matt and Jonathan said they were comfortable lumping things above the Feather and then things below the Feather. Jonathan said he doesn’t know if we would try to route them through the Yolo Bypass because the timing is different (March – May is when they go through). Matt said all the rearing is upstream and smolts don’t stick around in this section. Jonathan said the habitat below the Yuba doesn’t hold fish as well, temperature isn’t great, and water quality isn’t good. They haven’t seen fish outside of the Feather in there. Sarah said that smaller fish could be using it and that it is an unknown. Folks said the breakup for the Delta is fine. Steve T. said that water quality is really poor in the San Joaquin mainstem, but would stick to the tributaries. Jonathan said the Delta doesn’t have the most favorable conditions for rearing either. Michelle said the anadromous fish are estuary fish too based on otolith data. Jonathan said they are seeing that in the American as well, so there may be a benefit to these areas in the Delta. Mark G. said we probably need to add “miscellaneous ephemeral tributaries” in Upper Sacramento based on previous discussions.
The group started to develop the conceptual life-cycle model. Jim asked at what size/stage/age class they go out. Sarah said they might leave the tributaries early on. Matt said they see smolts but there are a lot of other classes where we don’t know what is happening. Jonathan said they most commonly see the 2+ fish that is likely to go out. He said they don’t see age 1 going out, but they don’t have the data to say it doesn’t. He said older ages can go out or may never go out. Jonathan said they spawn at age 3 at the earliest. That is, they spend 2 years in the ocean and 1 year back in. Jonathan said a 1+ mature male fish will occur for residents. Sarah said she thinks females spawn at age 1, 2, 3, etc., but maybe they are older. Jonathan said it seems like the mature female resident fish are usually the age 2–3, and that is governed by temperature, habitat conditions, etc. Steve T. said there is limited data on this for the San Joaquin side. Bob said that there are alternative strategies within an individual and that there does need to be some interaction between those adults. Jonathan said if they make the estuary trip they will come back as a 2 year old…on a 2–3 year life history strategy. Jim asked if the group wants age or sizes. Sarah said age would be preferable instead of size. Jonathan said age is easier to track in the anadromous life history and that size can vary markedly across age classes. Jonathan said to reach the doubling goal in a perfect world you would have to lump the life histories and looking at otolith or scales…but that is not conducive to survival. Jonathan said if it went to the ocean and went back that is the steelhead/anadromous life history. Steve T. suggested we eliminate the different resident and migratory branches in the life-cycle model and then have transitions to the ocean, so we aren’t thinking about them separately. Brett suggested breaking the tributaries up by foothills or valley floor. Mainstem is spawning above a certain point and Mark G. will work on getting this information. Jonathan said that the only thing that is finite is length of time in ocean and estuary. Everything else can happen at every time step. Jim asked what time step would be good for this model to match the biology of steelhead. Sarah said monthly would work and others agreed. Steve T. said that in a perfect world the fish would rear in the San Joaquin but we don’t think they do it now. Steve T. said the valley floor does not occur in the lower system. Michelle said there isn’t any opportunity for mainstem in the Delta. No spawning in ephemeral tributaries in southern tributaries.
The group continued to develop conceptual models .
Laura Heironimus, Marty Gingras, Mark Gard, Russ Bellmer, Shelly Hatleberg, Brett Harvey, Dan Kratville, Mike Urkov, Cesar Blanco, Mike Thomas, Felipe Carrillo, Jim Peterson, Adam Duarte
Jim started off by providing an overview of the Chinook Salmon models and the structured decision making process. He reviewed a project he worked on for Klamath Suckers as an example of how we deal with uncertainty using decision-support models.
Jim presented the objectives and management scenarios identified by the group during a previous phone call. He also showed the Sturgeon conceptual life-cycle model developed by a Sturgeon group in 2014. He asked the group if there are any new objectives the group may have. Marty said the current list looks like what is in the Green Sturgeon recovery plan and he thinks those lists are in agreement more or less. Laura asked about the size of spawning aggregations. It was brought up in a previous phone call and she wanted to know why it was not chosen. It is a large unknown and could be influenced by the amount of spawning habitat. Right now there is an annual spawner abundance survey and those data have been collected over the last ~5 years. Mike says when he thinks about aggregation it is a group of individuals around a spawning site. Mike said there is a genetic component associated with it. Laura said it also influences your likelihood of success. Laura said a spawning aggregation is the number of fish within a habitat unit. Jim asked if there is a number criteria to be considered an aggregation. Mike said Ethan has a better idea on this. It is based on counts that are then extrapolated to the greater population. They use the aggregation location to drive where the expected fish are. Laura said it could be the number of females and the total parent contribution to those eggs.
Jim asked if there were any edits to the management actions. Marty wanted to eliminate “increase” and change to manage temperatures in spawning and rearing grounds. Marty said managing contaminants (selenium) usually makes these types of lists. Mark wanted to add the reduction of unscreened diversions. Mike agreed.
Jim then asked about the spatial grain of the model and if any changes needed to be made. Mike said they typically look at what constitutes a spawning ground, what is below that is the migratory route, and then the nursery and forage grounds. Marty thinks it’s not worth separating the Delta. Mike said we don’t know if they rear in any of the bypasses. We know fish end up in them, but we don’t know the route selection. They are important to think about when managing the adults. They did track some individuals on the spawning grounds and they all went straight down the river. Mike said they spawn just below Deer Creek. Highway 32 or 162 up is historically considered to be spawning ground. Russ said Highway 162 up to Keswick dam is closed for fishing. Russ said the surveys for spawning goes down to Hamilton City. They have targeted 174 spawning territories and he said it may be worthwhile to consider the number of spawning areas occupied as it might be a better metric because it is something quantifiable. Russ also doesn’t know if the number of rivers where spawning occurs is a good metric. Mike said he will send a draft manuscript he has that looks at the distribution of the spawning with and without the dam. He said they do go above the dam. There does seem to be a line they stop and it is uncertain if that has to do with temperatures or not. It is a big question how the winter run Chinook releases are influencing the distribution on Sturgeon spawning. Mike said about half fish outmigrate in summer and about half the fish oversummer and go out in the winter. During this time, they are putting on energy reserves and they are feeding. They have spawning habitat and they use it different pre- and post-spawning. Marty said they have a report that is coming out that is defining habitat around spawning locations over the last 2 years. Mike said they have documentation that will add to that as well.
Jim asked about timing. Mike said peak spawning is April to July with a peak in May-June. Bill has information on when they find juveniles. Joel has work on eggs to larvae.
Jim asked about the life-cycle model. Mike said they look at age class to track cohorts. DFW does that with the white Sturgeon to get cohort strength. Marty said they also track cohort strength and it is the best thing they have to track cohorts. Mike said an adult is based on a size range that could contribute. Laura said they don’t spawn every year. Mike said the spawning range is 2-5 years. Female repeat returns is 3-5 years. Mike said non mature fish move up the Klamath but they haven’t seen much of that. Generally speaking, if they are on the spawning ground they are sexually mature. Subadults are individuals that don’t make a migration typically but you see them popping in and out of San Francisco Bay. Mike said that when they oversummer they typically respond to peak flows to outmigrate in December. Mike said they are capable but they have not seen back-to-back spawners. Laura said they see back-to-back spawners for white Sturgeon. Mike said we don’t have a good understanding of how long juveniles hang around on the spawning grounds. They think it might be temperature related. All the individuals that were tagged this year moved out at roughly the same time. All the captures occurred around Red Bluff and based on size it suggests they reared Red Bluff on up. When there is a pulse flow they moved, but this is based on 1 year of data. There is probably some proportion that stick around for a year. Laura said that she got some otolith data from large fish from Bill and they looked like age 0 fish that had just gone through rapid growth. Marty said that we have enough information to say age 0 and age 1 are on spawning habitat, but that we probably won’t be able to monitor it effectively. Mike said that the age 1 are moving to the delta. Marty said they would like to see if there are survival differences, but they are a long way away from that. Russ said juvenile fish in the delta can move back up. They are moving much more than initially envisioned.
The group continued to develop the conceptual model. Russ said the size ranges they are getting in the Halibut trawls is in his data and he will provide those estimates. The smallest was FL of 68 and largest of 132 cm. 132 depending on sex is approaching maturation. 150 cm is the lowest Mike has seen on the spawning grounds. Russ said satellite data is from a bycatch study. These are individuals caught in the Halibut trawls. Subadults are larger juveniles and both move back and forth between the delta and ocean. Mike said the sDPS and nDPS spatial distribution are based on genetics. Size of adults that return are from 140 to 217 cm. Mike said that you would probably need to break up the sizes if you track fecundity. It is a function of age but age data are sparse. Based on 30 individuals, age at length for southern DPS was larger than northern DPS. Marty said for present purposes he doesn’t think we should break them up by size since there is no management action on that or any biological importance. Mike asked about fecundity potential. Marty agreed and said we need to refer to spawning periodicity. Laura suggested using the proportion or percentiles of the handled adult fish. Mike said a 2 m sturgeon is a relatively large sturgeon. Group decided to not track size in the conceptual model for now. The group agreed on the base conceptual model.
The group started to develop the submodels for the transitions. First transition is egg to fry. Joel Van Eenennaam animal sciences at UC Davis is a good person to talk to on the influence of factors on fertilization. You don’t want the substrate rolling post-spawning. Selenium is dumped on white sturgeon which could be a problem for egg production. White sturgeon selenium uptake is primary through their diet in the Bay (invasive clams). Green spend more time in the ocean so it may not be an issue but they do hang out in the bay. Mike said he doesn’t think they retain selenium uptake over their life. Marty said there is evidence that females can accumulate it really fast, but green is less influenced by it. Mike said the adhesiveness of the egg starts at fertilization, but to confirm this with Joel.
Next transition is larvae to age 0 natal area and delta. Optimal growth is around 16 C. When you get around 14 C growth begins to slow and this is around October. Mike said they are probably passively transported to the delta by drifting in the current. Laura said they passively move probably for a week or two after which they do have some control on where they go. Mike said movement was in response to a pulse flow all the way to the delta. Mike said he would hypothesize that once they are through the Sacramento channel they are benthically feeding in the delta. Mike said you see them moving back and forth and it is probably due to tidal wash, but they do maintain some site selection during rearing. Mike said he wonders if there is some habitat condition influence on movement of younger sturgeon. Marty said that sturgeon are not found in gut contents very often. Laura said that the larvae to age 0 are the most likely to be preyed upon. Mike said Joel said green sturgeon are somewhat resistant to iridovirus.
The group continued to develop conceptual models. Age 0 movement to the delta was first. Mike said it may be a time of year and flow response…and maybe a condition factor. A one day spike in flow is all that is needed to get a movement response. Next was age 0 movement to the ocean/bay. Mike suggested a temperature response for thermal refugia. Laura suggested a seasonal food attractant. Mike discussed it may be timed with herring reproduction. Russ said when they looked at this they did not find any Sturgeon in the herring balls. Marty clarified that Mike was talking about herring eggs, not fish. Next was age 0 from ocean/bay to delta. Russ said based on his data there didn’t seem to be any correlated factors, but they were looking at post-capture (bycatch) survival. He has seen age 0 fish a little past Rio Vista. Mike said it is unlikely they will venture back upstream to the freshwater environment once they are able to persist in the saltwater environment. The tidal pulse is probably what is getting them up to Rio Vista area. Russ agreed. Russ said it could be foraging behavior. Next was age 0 to age 1 freshwater survival. Laura and Mike talked about predation being an issue with sea lions when salmon aren’t present. Marty said they have seen them take Green Sturgeon but not White Sturgeon. Next was age 0 to age 1 in the delta. Mike said boat strikes. Jordon Gold was doing dredge operations and Mike said he hadn’t seen Sturgeon bycatch. Marty said that for larger fish in gill nets they do not see evidence of boating collisions.
Next was age 1 to juveniles. Entrainment occurs but with really low numbers. It is also plausible that a change in operations can change the magnitude of the number of entrained fish. Next was age 1 movement from delta to ocean/bay. Mike wanted salinity added. Antioch is furthest in San Joaquin straights. Many of the nodes were the same. Next were juvenile movement in the delta to ocean/bay. Russ wanted food to be replaced by delta inflows. Survival was left the same as before. Next was subadults. Group said it was the same but the magnitude of the effect was less.
Next was adult survival out of the basin. Russ wanted to drop temperature, disease, and contaminants. Alternative prey was removed. Mike thinks food availability is more related to movement. That is, if there is no food they will move to the next inlet. Next was adult movement to spawning areas. Mike wanted stream size and temperature, and said when they come in they are mature and ready to spawn. It was discussed how we might be able to attract adults with pulse flows. Mark G. mentioned passage barriers. Laura says they see the pulse flow movement/spawning relationship for White Sturgeon. Holding/spawning areas are generally 5-8 m deep. Adult pre-spawn survival was next. Predation, stranding and poaching were added. Laura added temperature. Marty wanted bycatch added. Next was adult post-spawn survival, in river. Mike said stranding isn’t so much of an issue here. Marty asked about emaciation when holding oversummer.
Jim asked about an appropriate time step for the model. Marty said one month should be fine but the pulse flows are of shorter duration. Jim discussed how we do that for the fall run model. Marty liked that approach. Mike used a month time step for another project with Green Sturgeon. Mike said the arrival is the beginning of April plus or minus 3 weeks. Joel has data for when they spawn to look at post-hatch timing. Bill has decades worth of screw trap data at Red Bluff and then some egg mat data but green and white data are not differentiated well. Some of these data are summarized and available in online reports. Felipe suggested we ask Bill about these data ahead of time, since it will likely take a while to organize.