- Learning to use the Egg killer
We recommend learning the methods and controls of this tool with simple experiments. Use the upload and input methods to do trivial tests using one or a few redds in simple temperatures or gradients. Compare modern years to historic years.
Also, consider only adjusting one control at a time in order to track how the model is responding to each change.
- Temperature and redd counts format
Both upload and input formats are multi-column, comma separated variables.
Day-of-year is first column. Blocks of days can be condensed with format: "first_day:final_day" Subsequent columns are
values at different river positions identified by River Kilometer. When this condensed format is used, temperature values can also be specified in this condensed method as "value1:value2" which will interpolate
between these two values for the range of days found in the first column.
Column name format MUST be: "RKMxxx" where xxx is numeric. E.g.Day,RKM483,RKM479,...
At @ site, 2 years worth of temperature values are required
due to the calendar-year-spanning life history of Winter Run Chinook Salmon. There is currently a limit of 5 sites.
If you Upload data, it will be placed in the text area as input values awaiting "Run".
"Plot days" and "RKM range" control plotting
of temperature heatmap and timeseries.
TCrit is the temperature below which there is no temperature induced mortality.
"Crit period" is the critical number of days prior to and including hatch day when temperature exposure is computed.
"Crit type" selects how the exposure is identified during the critical period.
- Temperature computation, use and display
If a single timeseries is uploaded, then the temperatures are used at all locations. If two or more timeseries are uploaded, the model uses the river kilometer of the known temperatures to
interpolate (linearly) the temperature at the unknown site. The temperature "landscape" varies spatially and temporally with specific temperatures for each redd location.
The timeseries of temperatures at the gauges, upload sites, and/or redd locations are shown on the graph. Superimposed on this graph is depiction of the redds within the gravel at three different stages: pre-hatching, hatching and the critical duration prior to hatch, post-hatching as alevin.
- Density by Reach vs. Density by RKM
Currently, the redds can be placed in one of three reaches OR at any River Kilometer (RKM) of interest.
To use "Density by Reach", you can simply query the database. An alternative is to input or upload redd data with specific headers:
Keswick to ACID dam (5.5 Km) use RKM483
ACID dam to Hwy44 (3.3 Km) use RKM479
Hwy44 to Airport Rd. (19.7 km) use RKM470
Airport Rd. to Balls Ferry (12.8 km) use RKM445
Balls Ferry to Battle Crk (7.7 km) use RKM440
Battle Crk to Jellys Ferry (8.0 km) use RKM430
Jelly Ferry to Bend Br. (14.5 km) use RKM415
Bend Br. to RBDD(23.5 km) use RKM395
IF you upload or (type-in) redd data in the textarea: you will need the headers to match exactly.
For reference, sites of interest and river kilometer are shown below:
|ACID dam ||480.5||298.6|
|SAC gauge ||478.3||297.2|
Use of lower reaches is rare in recent years. To use the model for locations below Airport Road, it is recommended to use the "Density by RKM" method. Redds in the database more than 94 kilometers downstream of KWK are ignored.
You may get different results when switching between these methods because ...
1) redds were deposited far downstream/outside of the designated reaches so counts are different.
2) density effects are allocated differently
3) temperatures are unique to each location and there are only three reach locations.
- Carrying capacity
The Beverton-Holt density-dependent component of mortality is based on local density on a per-kilometer or per-reach basis (Anderson 2018).
Density dependence is considered a localized phenomena. Dewatering in marginal habitat and/or super-positioning of redds is the proximal cause of egg and alevin mortality during the in-gravel
residence, so only the local density matters. (The alternative is that the density of post-gravel fry is important after they begin swimming freely).
Carrying capacity is computed as either: redds/kilometer or redds/reach. When the reach method is chosen, the sum of all the redds in the reach and the
length of the reach are used to find the average density. You will likely get different results when switching between these methods.
Martin et al. 2016b used 9107 for the entire river's carrying capacity but is blind to the spatial distribution of the redds
- Redds vs. carcasses
Currently, the method available to use these carcass data is to convert them to redds outside of the model, place in a properly formatted file, and upload or paste into the Redds' "Input or upload" area.
This may be best handled with the reach method, given the uncertainty of exact location. Although carcasses are used to enumerate redds in the field, there are two problems with application to this model:
neither the time of redd completion, nor the location of the redd are known.
- Colors in the tables
Red fonts in the results tables depict when a redd was exposed according to the user-selected criteria: the critical temperature,
the nature of exposure (all incubation vs. just-before hatching), the duration of the exposure (a few days near hatching or the entire incubation period), and exposure calculation.
- Exposure and temperature-related mortality calculation
IF "Eggs sensitive ALL incubation" is selected, then when the temperature rises above Critical Temperature (T-crit) on any day for each individual redd, mortality is computed.
IF "Eggs sensitive prior to hatching" is selected, then when the temperature rises above the T-crit point during the "Crit days" prior to hatching, mortality is computed. Mortality is always computed
on a daily basis. This should not be confused with "Exposure". Exposure can be based on a multi-day average or a maximum temperature. It is possible that a multi-day average temperature not exceed the
critical level, yet one or more days triggers mortality because individually they are above the critical value.
The functional forms of the mortality equations can be examined: Explore Egg/Fry survival models