I have compiled my rudimentary observations in spreadsheet form to make searching for specific data and some minimal level of analysis possible. Both LibreOffice spreadsheets (.ods) and Excel versions of those spreadsheets are listed for download below. Although I have given them my best effort, the spreadsheets are unlikely to be free of errors.
Files that can be downloaded:
Names
Length Measurement Uncertainties
Variables
Cautions on Use of Data
Names
Few of the water bodies I have visited are named so most of the names I use here are made up. They generally refer to nearby named topographic features or, exceptionally, salient characteristics on the day of the first visit. Water body names that are shown on topographic maps are placed in quotations to identify them as real. I do this even for water body names that may be recognizable to the public.
Length Measurement Uncertainties
Pond sizes, pond depths, and fairy shrimp lengths are visual estimates in almost all cases and subject to large uncertainties. In a few cases, pond dimensions have been paced off, pond depths have been measured with a scale, or a scale has been held close to swimming fairy shrimp. Ponds have irregular bottom topography so not all depth measurements give the same result. Not all fairy shrimp of the same generation are the same length. Although imprecise, I think that reporting such measurements is nonetheless helpful.
Distances along roads are reported in miles to correspond to odometer units in almost all vehicles in the United States. Highway distances are taken from state highway maps and are reliable. Off-highway distances are estimated from 1:100,000-scale topographic maps with a scale or by counting 1-mile long PLSS sections but not all twists and turns are accounted for so the lengths could be up to about 20% too short.
Distances between geographic features, including ponds, are estimated from 1:100,000-scale, or rarely 1:500,000-scale, maps with a scale. Because they are straight-line distances, they have good precision and accuracy but differ appreciably from hiking distances.
Variables
These are the variables included as columns in the spreadsheet, from left to right.
Pond
My made-up name for the water body unless the body is named on a topographic or USFS recreation map, in which case that name is used and placed in quotations.
Locality
The physiographic or geographic region in which the pond is located, usually a mountain range or basin. Regions differ by climate, likely abundance of fairy shrimp habitats, and accessibility so these names will provide those familiar with the localities quick indications of the feasibility and timing of a visit.
Date
Date of the visit. Due to the seasonal nature of many ponds, the month and day of the visit are important. I didn’t really want to provide a timeline of my life but including the years of the observations will make it possible for interested individuals to determine whether it was a wet, dry, or normal year from meteorological records and adjust expectations for finding fairy shrimp accordingly. Year data could also be used to constrain times of extirpation or colonization, if any.
Status
Fairy shrimp status is recorded as “present” or “absent” if there is water in the pond or “dry” or “snow” otherwise. I use the entry “unknown” in the few cases where I wanted to establish the existence of the pond but couldn’t get to the water to look for fairy shrimp or couldn’t have seen them through the ice.
Origin
Natural and anthropogenic origins are distinguished. If I am uncertain of the origin, “uncertain” is the entry.
Section/Township/Range
Most paper topographic maps show public land survey boundaries as a square grid of 36 sections with nominal areas of 1 square mile (640 acres) within townships numbered consecutively north or south of a meridian (the township coordinate) and consecutively east or west of a meridian (the range coordinate). Consequently, this information offers a handy way to find the approximate location of a pond more easily than trying to scale off the rectilinear UTM coordinates (or worse – I have a 2006 BLM 30- x 60-min quadrangle that doesn’t even show the UTM and State Plane tick marks). The section is a good alternative for locating a pond on a map when the location is specified in degrees latitude and longitude. Degrees latitude and longitude are not the same lengths and longitude lengths change dramatically from the equator toward the poles, lines of latitude and longitude are not perpendicular on a flat map, and the degree-minute format is not base 10, all of which make determining the latitude or longitude of a point on a paper map difficult. Unlike UTM coordinates and degrees latitude and longitude, sections do not depend on a datum.
Survey errors (most of the surveys in the western United States were in the 19th century) can result in section lines that are not parallel or perfectly aligned north-south and east-west but the lines are fixed to physical locations by the placement of section corner markers (e.g., rocks, pipes) on the ground. Such errors do not affect which section a pond is in. Errors in determining which section a pond is in arise when the pond is close to a section boundary and the topography offers poor resolution, such as in relatively flat areas.
Some parts of the United States have not been surveyed. Unsurveyed areas are commonly mountainous areas where nobody lives, such as the Wind River Mountains. Nevertheless, Ranger District recreation maps prepared by the Forest Service and The National Map may show section boundaries which are simply extrapolated from nearby surveyed areas. If present, I use such boundaries to estimate which section a pond is in.
Species
Fairy shrimp species (or occasionally just genus) are entered if Denton Belk (DB) identified the species from specimens I sent him. In a very few cases, I have entered a name followed by a question mark if I am confident of my own identification. “Not identified” is used for dates where I did not collect specimens for DB even if a species was identified in the same pond on a different date. The entry is “none” if there are no fairy shrimp or the pond is dry or “indeterminate” if I couldn’t get to the water or the ice was too thick to see through. In the rare cases where 2 species were identified in the same pond at the same time, both are listed. It is of course possible that the specimens I collected were not representative and species other than the one identified were present. I generally did not collect more than 20 individuals and there are a few cases where I was only able to collect 5 or less.
Longest
Millimeters. This is the estimated median length of the longest group of fairy shrimp from the forward end of head to the rearward end of abdomen as estimated visually, rarely with scale in hand. Lengths are reported to the nearest millimeter. If my field notes only gave a range, the median of the range is used. If my field notes have only a maximum value, a value 1-2 mm less than that is reported.
Practically, the median is the most common length that I saw. I never calculated a median from individual measurements. For the Wyoming observations, if I measured lengths of the specimens I collected, I use that as the length estimate even though it may not be representative due to small sample sizes.
Presumed single generations generally have small ranges of lengths. For example, I considered a range of 5 mm for fairy that are mostly 15 mm long as normal for a single generation. Determining whether there were generations of more than one size was rather ad hoc. It depended largely on whether I saw numerous individuals of distinctly different lengths. An abnormally large, but not too large, range with many intermediate lengths was treated as a single generation. Ultimately, choosing between one and two generations was subjective. It is more likely I mistook multiple generations for one than that I mistook one generation with a narrow hatching interval for two or more generations. My interpretations of different generations should be considered very imprecise but they nonetheless may offer a useful approximation of the minimal population complexity.
In cases where males and females seemed to have distinctly different lengths but the same sex was mostly the same length, a length intermediate between that of the males and that of the females is reported.
The length given may differ from that of the description of the visit where additional context can be provided. “none” if the pond was dry or there were no fairy shrimp. “not estimated” if I didn’t record a length. “Indeterminate” if I couldn’t get to the water to look for fairy shrimp or the ice was too thick to see through.
Other Length
Same as “Longest” but applied to a smaller group of fairy shrimp.
In cases where I determined that one generation hatched over a short time period and was all about the same length or where I didn’t note more than one generation, the entry is “unimodal”.
In cases where I determined that two generations were present, “other length” is the median length of the shorter generation. Again, this is subjective.
If fairy shrimp lengths had an usually wide range or appeared to cluster into more than two groups, the entry is “various” rather than a length for one of the shorter generations. Further details may be given in the description of the visit.
“none” if the pond was dry or there were no fairy shrimp. “not estimated” if I didn’t record any lengths. “Indeterminate” if I couldn’t get to the water to look for fairy shrimp or the ice was too thick to see through.
Eggs
The presence of eggs is an easy indicator of whether a fairy shrimp population is mature. Visible presence of eggs is noted as “common”, “present”, or “absent”. “Common” means eggs were present in the majority of females. Any visible egg counts as an egg, whether in the ovisac or in the oviducts. In my notes, I used “common” sparingly so although “common” means common, “present” does not exclude common. In multimodal populations, one can assume that any eggs present are in the population with the larger size. Whether a smaller population has eggs may be clarified in the description of the visit.
“none” if the pond was dry or there were no fairy shrimp and “not noted” if I didn’t record whether there were eggs or not and don’t have photographs. “Indeterminate” if I couldn’t get to the water to look for fairy shrimp or the ice was too thick to see through.
Water Color
Generally noted as “opaque”, “cloudy”, “murky”, or “clear” as described below with color terms added for noticeably colored water. Practically, it is difficult to separate the color of the water from the color of the pond bottom so it is likely I have overemphasized water color.
- opaque – can’t see anything much below the water surface
- cloudy – can see 1-3 cm (0.4-1.2″) below water surface
- murky – can see a few cm below water surface
- clear – can see details on pond bottoms more than 15 cm (6″) deep but maybe not in the deepest part of the pond
“not noted” if I didn’t record a water color and don’t have photographs. “no water” if the pond was dry.
Water Temperature
Degrees Celsius. Measured to the nearest whole degree using a small aquarium thermometer after the temperature has stopped changing, usually at least 5 minutes. This is probably within 1 degree of the actual temperature but not necessarily representative of the pond due to placement bias (e.g., close to shore, near surface).
The presence of ice is also noted in this column. The occurrence of ice is usually described in more detail in the description of the visit.
“not estimated” if I didn’t record a temperature or the presence of ice. “not noted” if I recorded a temperature but not the time. “no water” if the pond was dry.
At Time
24-hour clock. This is the time at which I measured the temperature or saw ice. Because water temperatures can vary by 5 C and possibly more than 10 C in a day, a temperature without a time is not very helpful. The number is preceded by an apostrophe to convert it to text.
“no measurement” if I didn’t measure temperature. “no water” if the pond was dry. “all day” if the pond was so full of ice or snow that it was clear it would last all day.
Max Width
Meters. The maximum width of the pond was estimated visually or, rarely, by pacing. For the small West Northumberland Road Ponds, I even used a tape measure but those ponds are described in the description of the visit and there is only one pond described in the spreadsheet. For collective descriptions of groups of ponds (e.g., Austin Summit, Smith Creek Cold Springs) this width applies to the largest pond at the time unless otherwise noted in the text. Estimates are probably within 25% of the actual maximum width but intentionally underestimated for ponds with variable widths where only a small proportion of widths were close to the maximum.
In cases where the maximum width was measured on a topographic map, this is noted in the description of the visit. The actual width on the day of the visit could have been different but if the pond was obviously much smaller than the map size, the map width is not used.
500 is the maximum value used and means greater than or equal to 500 m. My ability to estimate lengths greater than 500 m is highly suspect, by me. This width may differ from the description of the visit where additional context can be provided.
“not estimated” if I didn’t record any pond dimensions or only estimated the length. “no water” if the pond was dry.
Max Length
Notes are the same as Max Width but applied to the maximum length.
“not estimated” if I didn’t record any pond dimensions. “no water” if the pond was dry.
Max Depth
Centimeters. The maximum depth of the pond was estimated visually or, rarely, by measuring if less than 30 cm. In some of the few cases where I measured, I measured up the side of my boot which may have sunk into the mud an indeterminate amount below the undisturbed pond bottom. For collective descriptions of groups of ponds (e.g., Austin Summit, Smith Creek Cold Springs), this depth applies to the deepest pond at the time unless otherwise noted in the description of the visit. The depth is probably within 25% of actual maximum depth but the coefficient of variation likely increases with increasing depth and decreasing water clarity. Where the clarity is not “clear”, max depth may have been estimated by the slope of the surrounding land surface and could be off by 50%. 200 is the maximum value used and means greater than or equal to 200 cm, as visual estimates of greater depths are presumptuous and equally indicative of year-round persistence. Where the maximum depth is estimated to be greater than a specific depth, that depth is appended with “>” (i.e., 50> means greater than or equal to 50 cm, the number is first to facilitate sorting).
This depth may differ from the description of the visit where additional context can be provided. In some cases, I gave a depth in the description of the visit but entered “not estimated” in the data spreadsheet due to large uncertainties.
I have been surprised at how flat ponds can be even when the banks have significant slopes. Consequently, I likely overestimated some pond depths, particularly in the early years. Depths reported for ponds with opaque or cloudy water are not reliable unless I waded into it.
“not estimated” if I didn’t record pond depth. “no water” if the pond was dry.
Other Species
Other animals that may be relevant to fairy shrimp living conditions.
This includes other aquatic macroinvertebrates that I know something about and that can be seen clearly enough to recognize. I can’t identify the species of such animals so I give more generic names, such as “cladocerans”, “copepods”, or “ostracods”. For insects, I give the order or family if I can.
I mention birds, which can play an important role in dispersal, and likely amphibian predators. For birds, I may give a common name for the species if I know it based on identification using “The Audubon Society Field Guide to North American Birds, Western Region”.
“not noted” if I didn’t mention other animals in my notes. “none observed” if I was confident that no other macroscopic animals were present. “no water” if the pond was dry.
UTM Zone
In the UTM coordinate system, Earth is divided into 60 zones which are 6 degrees of longitude wide (maximum width 674 km at equator) stretching from pole to pole. Nevada is in zone 11 and Wyoming is in zones 12 and 13. The zones are divided into latitude bands of 8 degrees. Latitude bands in the northern hemisphere are labeled alphabetically from N at the equator to X near the pole. Wyoming is entirely in band T but Nevada is in both T and S. Both the 2-digit zone and the band are entered, e.g., 11S. This is what is normally displayed by a GPS device.
Northing, Easting
The north-south, or east-west Universal Transverse Mercator (UTM) coordinate. NAD83 datum. If a GPS was not used (e.g., for all of Wyoming), these coordinates were obtained from The National Map by clicking on the pond location, as determined by examining the map and aerial imagery layers, and using the spot elevation tool to display the coordinates.
Wyoming pond coordinates that are particularly uncertain because the pond location is not well constrained by topography and the aerial imagery is ambiguous are colored red. Additional context may be provided in the description of the visit.
Coordinates obtained using GPS are necessarily at the edge of the pond so those obtained using the spot elevation tool are similarly situated.
Repeat measurements and good correspondence between GPS locations and ponds shown on the The National Map and USGS aerial imagery suggest the GPS coordinates are within 10 m of the actual location. Where GPS locations differ significantly from the pond location on The National Map (e.g., 140 m for Bass Flat Southwest Pond, 35 m for Virginia Creek Pale Green Pond, and 10 m for “Par Value” North Ridge Pond), the GPS locations are supported by USGS aerial imagery, which can be viewed at the same zoom level and browser coordinates as The National Map by changing the base map in the The National Map Viewer. If The National Map basemap layers are properly projected in the browser, location accuracy for the coordinates obtained from The National Map are limited by the resolution of the mouse and the shakiness of my hand on the mouse. The coordinates are certainly accurate to within 10 m (based on adjacent clicks) and probably to within 5 m.
Elevation
Meters. This is obtained from The National Map (TNM) by clicking on the pond location, as determined by examining the topography and aerial imagery layers, and using the spot elevation tool. Position precision is likely better than 10 m so elevation precision is probably quite good. Off the top of my head, I can’t think of any ponds in terrain so steep that elevation would differ by more than 5 m from a point 10 m away. I don’t know the accuracy of The National Map’s spot elevation tool.
Wyoming pond coordinates that are particularly uncertain because the pond location is not well constrained by topography and the aerial imagery is ambiguous are colored red. Additional context may be provided in the description of the visit.
I have not used elevations determined by GPS device because I have experienced repeat errors up to 10 m. In addition, the random errors introduced into GPS readings can give ponds that are close together and at very close to the same elevation different elevations and can reverse the elevation ranking of ponds that are close together and at slightly different elevations. For example:
- The GPS elevation of Rhodes Potholes is 4 m higher than Rhodes Grassy Pools and 5 m higher than Rhodes Big Lake although it is on the playa between the two and water flows from Rhodes Grassy Pools to Rhodes Potholes and thence to Rhodes Big Lake. The TNM elevation of Rhodes Potholes is the same as that of Rhodes Big Lake and 1 m lower than that of Rhodes Grassy Pools.
- The GPS elevation for Smith Creek Ranch Road Long Ditch Pond is 5 m lower than that of North Smith Creek Playa Channel Ponds although it is visibly higher. The TNM elevation is 2 m higher.
- The GPS elevation for Paymaster Canyon Road Stock Pond is 9 m higher than that of Cross Playa Rivulet Pond although both are on the same playa. The TNM elevations are the same.
- The GPS elevations for Win Wan Corral Pond and Win Wan Flat West Pond differ by 4 m although both are on the Win Wan Flat playa. The TNM elevations differ by a more reasonable 1 m.
For the Nevada and California ponds on this web site, GPS elevations differ from TNM elevations by up to 14 m higher or 14 m lower, except for 18.6 and 17.8 m differences in the steep topography of the “Par Value Lakes” area.
GPS/TNM
“GPS” indicates a recreational global positioning system device was used to obtain the UTM coordinates with the following settings: NAD83 datum, GRS 80 spheroid, WAAS enabled.
“TNM” indicates The National Map was used to obtain the coordinates.
County
This is the county in which the bulk of the pond is located. This may be a useful search term in some species databases.
Latitude, Longitude
Decimal degrees. NAD83 datum. These were obtained using the spot elevation tool of The National Map. If I had GPS data, I used trial-and-error clicking of the spot elevation tool until both Northing and Easting were within 10 m of the GPS coordinates. The spot elevation tool displays both UTM coordinates and latitude and longitude so I copied the latitude and longitude for that location. This was easier than using a coordinate conversion algorithm since I was using the spot elevation tool to verify the GPS coordinates and obtain elevations anyway. As a result of this method, latitude and longitude coordinates are not as accurate as UTM coordinates but are unlikely to be more than 20 m off. If I did not have GPS coordinates, I clicked on the pond using the spot elevation tool and recorded both the UTM and latitude-longitude coordinates for that point.
Wyoming pond coordinates that are particularly uncertain because the pond location is not well constrained by topography and the aerial imagery is ambiguous are colored red. Additional context may be provided in the description of the visit.
7.5-min Quadrangle
Name of the USGS 1:24,000-scale 7.5-minute topographic quadrangle on which the pond occurs. Where I used a 1:62,500-scale 15-minute quadrangle in Wyoming, 15′ is appended to the name.
30×60-min Quadrangle
Name of the USGS 1:100,000-scale 30- x 60-minute topographic quadrangle on which the pond occurs.
Cautions on Use of Data
I probably haven’t thought of all the problems but these are ones where caution is definitely advised.
Quality of Notes
The poor quality of the notes I took is a major weakness of the data reported here. Due to the long passage of time between my observations of fairy shrimp and when I prepared this web site, the notes and photographs are about all I have to rely on. The quality of the photographs is self-evident. Unfortunately, I didn’t take a lot of photographs before 2009 because of the high cost of slide film and developing. Even after I purchased a digital camera, it was a long time before I began photographing things that only might be interesting and tried multiple shots of the same scene.
With my notes, I did not set out to document the occurrences and habitats of fairy shrimp. I initially intended only to keep track of where I saw them so that I could go back and visit at other times. As I became more familiar with the literature and began working with Denton Belk, I began making more thorough observations but still without any objective in mind. Overall, my note taking was haphazard and inconsistent. I wrote substantial notes for some ponds but little for others, particularly those without fairy shrimp. Except in the Wind River Mountains, I used 1:100,000-scale BLM maps to estimate locations. In the absence of nearby landmarks or topographic features, these locations could be off by more than 100 m (330′). Thanks to the online National Map viewer with rectified USGS imagery, the pond locations reported here have been improved to within 20 m (66′).
My estimates of pond sizes and depths have not been similarly improved.
Fairy shrimp lengths are imprecise because they are typically given as a range or as a length greater than or less than a certain amount. These numbers are biased toward multiples of 5, such as “10-15 mm” or “greater than 20 mm”. Length differences of less than 2 mm are not likely to be visually discernible by me. I would not now be confident, for example, that a “10-15 mm” estimate was not actually “13-16 mm”.
Identifications of other animals at ponds is based on my use of various sources with photographs, drawings, or descriptions. These identifications have not been independently confirmed. If there are photographs, use your own judgment.
Presence or Absence of Fairy Shrimp
On a single visit, I may never have spent more than 30 minutes looking for fairy shrimp. When pressed for time, I may have spent less than 10 minutes. In any case, I did not time the amount of time I spent actively looking for fairy shrimp. In most cases, I looked only from shore and did not wade into the water to look for fairy shrimp. That said, I would guess that when I found fairy shrimp I did so looking from shore for 10 minutes or less in 80% of the cases. Fairy shrimp seem to favor prolific hatches. They make it easy for us.
Factors which may have prevented me from seeing fairy shrimp when they were present include:
- Low population density – the fewer there are, the less likely I am to see them.
- Heterogeneous distribution – if they are not in the areas where I happen to look, I won’t see them. A preference for deep water in deep ponds is one example of this.
- Small size – the smaller they are, the harder they are to see.
- Wind – waves on the surface of the water make it difficult or impossible to see below the surface. Strong wind can also interfere with netting by blowing the sides of the net together and making it difficult to see if anything is in the net.
- Debris – debris on the surface of the water makes it harder to see what’s below and collects in the net, making it hard to tell if small fairy shrimp are present (e.g., “Alkali Lake” on March 25, 2019, in Alkali Valley).
- Turbidity – moderate turbidity makes it harder to see fairy shrimp; high turbidity means I can only find them using my net and my net necessarily samples a smaller volume of water than my vision would.
The bottom line is: “present” means I saw fairy shrimp during my visit but “absent” only means I didn’t see any. They may have been present in some cases where I didn’t see them due to the factors above, and possibly others.
Cladocerans and Copepods
Due to their small sizes, I find it difficult to distinguish between copepods and cladocerans so my identifications may be inaccurate. Further insight into my abilities can be found in the section “Other Crustaceans You May Find with Fairy Shrimp” on the Biology of Anostraca page. Equally important, I don’t know what other small aquatic animals I could confuse with cladocerans or copepods so what I call cladoceran or copepod might be something else entirely.
Aquatic Beetles
I can’t distinguish the adults of different species of aquatic beetles so I refer to all of them as “beetles”. I may use adjectives such as “diving” or “black” but these are descriptive and not intended to indicate a particular order or family. However, I can identify larvae of predacious diving beetles of the family Dytiscidae and refer to them accordingly as “dytiscid larvae”.
Backswimmers and Water Boatmen
Under favorable conditions, I can easily distinguish between backswimmers (family Notonectidae of sub-order Heteroptera) and water boatmen (family Corixidae of sub-order Heteroptera) but I have likely made mistakes. Errors are more likely in murky to opaque water and when the animals swam away quickly. Even if I caught some in a net, I may have made a mistake as they can have different orientations and behaviors compared to when they are swimming unconstrained. Given that one is a predator and the other is not, I have finally decided to try and take a photograph whenever I see one so that I will have a record I can refer to later. I have, in fact, changed my identifications based on photographs and that is one of the reasons I am including this note.
Making matters worse, I first saw both backswimmers and water boatmen in 2021, in Virginia Creek Pale Green Pond (East-Central Sierra Nevada). I had previously assumed, for convenience I guess, that only one of the 2 families would occur in the same pond. Consequently, once I decided that the animal with oar-like legs was a backswimmer or a water boatman, I would not notice that the other family was also present. This also helps explain why I sometimes had considerable difficulty figuring out whether a pond had water boatmen or backswimmers.