Fairy shrimp occur in ponds in a wide variety of habitats on all continents, including Antarctica (Belk, 1982). Fairy shrimp are not confined to natural water bodies. They also occur in anthropogenic water bodies such as the salt works in San Francisco Bay and roadside ditches (Eng, Belk, and Eriksen, 1990). In Poland, they occur in “temporary pools, ditches, large puddles, flooded meadows, etc.” (Goldyn and Bernard, 2008). In Belgium, they occur in “wheel tracks” (Vanschoenwinkel and others, 2013). In the western United States, they occur in stock ponds (e.g., Win Wan Corral Pond, Gabbs Valley Range).
Fairy shrimp do not occur in most of the larger ponds and lakes in the regions they inhabit because they cannot coexist with fish. Consequently, they are typically found in ponds not connected to streams and that are too small or too shallow to support fish (i.e., freeze solid in winter), dry up in most years, or have TDS too high for freshwater fish. In the past, fairy shrimp also occurred in alpine lakes and ponds that fish could not reach because of the steep topography and waterfalls. Now, most alpine lakes have been stocked for recreational fishing, at least in North America and Europe. Even in Patagonia (Reissig and others, 2006).
Fairy shrimp typically do not occupy all the fish-free ponds in an area where they are present. For example, of 200 lakes and ponds near the Colville River in Alaska, about 12% had Polyartemiella hazeni and about 4% had Branchinecta paludosa (Reed, 1962, the categories may or may not be mutually exclusive). The lakes and ponds were not connected to streams and probably lacked fish but Reed (1962) did not so state. The Sierra Nevada mountains have fairy shrimp (Eng, Belk, and Eriksen, 1990) but I haven’t found any in over 2 dozen ponds in the East-Central Sierra Nevada that I have visited.
The presence of an ecologically similar barren pond in close proximity to a pond with fairy shrimp has puzzled some. The erratic distribution of fairy shrimp within similar habitats is most likely due to erratic dispersal. Fairy shrimp rely on wind and pond-visiting animals to carry their eggs from pond to pond and the probability of that happening may be low, depending on the wind and the abundances and life habits of possible biological dispersal agents. As a result, finding fairy shrimp is rather unpredictable. For a few tips on searching, see “How to Find Fairy Shrimp” on the About page.
On the other hand, in some limited areas, fairy shrimp occupy all the ponds. Examples I have been lucky enough to find are the “Burnt Lake” area of Middle Washoe County (11 of 11 ponds on the first visit) and the Pine Grove Hills area (5 of 5 ponds but it took more than 1 visit to find fairy shrimp in all of them).
The following references give an idea of how widely distributed fairy shrimp are beyond North America and Europe. This list is neither comprehensive nor representative and has no implication for publication quality. Some of the articles are about experiments and most don’t mention distribution or more than 1 species.
- Arctic, including Greenland and Arctic islands of Russia and Canada – Lindholm and others, 2016.
- Siberia – Litvinenko and others, 2007.
- Mongolia – Marrone and others, 2015.
- China – Yang and Sun, 2024.
- Southeast Asia – Rogers and others, 2013b.
- Australia – Timms, 2012.
- India – Padhye and others, 2017.
- Uzbekistan – Marden and others, 2012.
- Iran – Atashbar and others, 2012.
- Tunisia – Naceur and others, 2012.
- Kenya – Hildrew, 1985.
- Senegal – Lahr and others, 1999.
- South Africa – Vanschoenwinkel and others, 2010.
- Antarctica – Hawes and others, 2008.
- Chile – De los Rios-Escalante and Salgado, 2012.
Fairy shrimp have colonized large islands, like Tasmania (Timms, 2012), Taiwan (Wang and others, 2014), Japan, Java, Bali (Rogers and others, 2013b), and Sicily and Sardinia (Mura, 1999), and some smaller islands of the South Shetland Islands in the southern Atlantic (Jurasz and others, 1983), Pribilof Islands in the Bering Sea (Johansen, 1921, p. 26), Canary Islands (Munoz and others, 2010) in the middle Atlantic, Balearic Islands in the Mediterranean (Petrus, 1990), and Corfu (Kerkira) in the Ionian Sea off Greece (Ketmaier and others, 2012). Artemia franciscana has been reported in Haiti on the island of Hispaniola, on Puerto Rico, on the Netherlands Antilles, and on the Galapagos, and undetermined species of Artemia have been found on Hawaii, the Bahamas, the British Virgin Islands, Antigua, St. Kitts, St. Martin, and South Caicos (Triantaphyllidis and others, 1998). These Artemia populations may not be the results of natural dispersal patterns as they could have been recently introduced by humans as sources of food for fish and shellfish.
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Fairy shrimp may be lacking from Iceland. Inspection of 34 “shallow lakes, temporary ponds, pools, and spring mosses” scattered around the island yielded 1 tadpole shrimp (Notostraca) species and several species each of cladocerans (Crustacea: class Branchiopoda, orders Anomopoda, Ctenopoda, Onychopoda, Haplopoda) and copepods (Crustacea: class Maxillopoda, subclass Copepoda) but no fairy shrimp (Scher and others, 2000). I have not found any articles that mention fairy shrimp in Iceland. This may reflect a lack of interest rather than a lack of fairy shrimp though. When a few people got interested in ostracods in Iceland, they found 7 new species out of 16 total in samples from 44 lakes, 14 springs, and 10 cave pools (Alkalaj and others, 2019).
The near absence of fairy shrimp in the Alps is even more puzzling. The potential habitats are abundant. There are 6,473 natural lakes larger than 0.005 square kilometer (1.2 acres) (Schirpke and Ebner, 2022). Excluding artificial reservoirs and unnamed lakes (have the Europeans really named most of their lakes?), the Alps have more than 2,400 lakes with areas of 0.5-50 hectares (1.2-124 acres) above the elevation of 800 m (2,620′) (Schirpke and Ebner, 2022).
I could find only 2 reports of fairy shrimp in the Alps. In the first, Branchipus blanchardi was identified in 2 small, permanent, alpine lakes and nearby temporary ponds at an elevation of 1,800 m (5,910′) in the Maritime Alps near the western border of Italy (Mura, 1999). In the same report, a map shows an occurrence of Chirocephalus diaphanus south of the B. blanchardi site, closer to the Mediterranean but probably still in the Alps. Branchipus blanchardi also lives in 2 temporary ponds within 300 m (980′) of “Cristol Lake” in the Hautes-Alpes of France (Alonso, 1989). Alonso (1989) collected 140 specimens in August 1987. His paragraph on geographical distribution implies there are other occurrences in the Alps above 1,800 m (5,910′) but doesn’t say where or how many.
A few French hiking web sites describe a hike to Lac de Cristol. One (lacsdemontagne.fr/pages%20web/05/Brianconnais/lac_de_Cristol/lac_de_Cristol.htm) gives the elevation as 2,244 m (7,360′). Photographs on that web site indicate the lake is above tree line. One photograph shows a white patch near the outlet that could be a dry pond less than 30 m (100′) across. Another web site (www.hautesvallees.com/en/la-claree/que-faire/en-ete/balades-et-randonnees-en-claree/top-10-des-lacs-de-la-claree/; in English) said the lake has fish.
The exclusion of fairy shrimp from regional studies of the Alps suggests they are very rare. A study which aimed “to describe the crustacean zooplankton communities of lakes in the montane zone of the northern fringe of the Alps and identify the main environmental drivers of species richness and community composition” failed to mention fairy shrimp (Horvath and others, 2017). 54 lakes at elevations of 400-1,200 m (1,310-3,940′) in Switzerland, Austria, and Germany were sampled. Another study which aimed “(i) to analyse the patterns of community assemblage in several groups of phylogenetically related species; (ii) to identify the main environmental variables explaining the species assemblages and (iii) to investigate the commonalities among taxonomic groups from which ecological thresholds could be defined” in alpine lakes of the Alps, Pyrenees, Tatras, Retezat, and Rila mountains also failed to mention fairy shrimp even though “planktonic crustaceans” was one of the taxonomic groups of interest (Catalan and others, 2009). 72 lakes above treeline in the central Swiss Alps, Tyrol (Austria), and Piedmont-Ticino (Italy) were sampled. For the 235 sampled lakes of all the regions, elevations were 1,311-2,990 m (4,300-9,810′), depths 0.7-23 m (2.3-75′), and areas 0.05-53 hectares (0.12-131 acres). The habitat is there.
In Austria, there are several species of fairy shrimp in many ponds in the eastern lowlands but none in the Alps (Eder and others, 1997).
There are a few fairy shrimp species that could do well in the Alps. B. blanchardi is obviously one. C. diaphanus occurs in many habitats, including mountains. In addition to the Italian occurrence in the Maritime Alps, it has been found in 4 small lakes at elevations of about 2,400 m (7,870′) in the French Pyrenees (Beladjal and others, 2007a). Branchinecta orientalis inhabits steppe and mountain environments in Mongolia, Tibet, Central Asia, Austria (Pannonian lowlands), Yugoslavia, and Spain (Horn and Paul, 2004). It has even been reported from a shallow pond 70 m (230′) long in the Khumbu Valley of Nepal at an elevation of 4,830 m (15,850′) (Manca and Mura, 1997). B. orientalis is clearly capable of surviving in the Alps.
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Another possibility is Branchinecta paludosa. Ferguson (1935) related that B. paludosa had been found in “Dwoisty Lake” in the Tatra Mountains of Poland. “Dwoisty Wschodni” is an intermittent pond less than 100 m (330′) across and up to 9.2 m (30′) deep with a boulder bottom (Kownacki and others, 2000). It is at an elevation of 1,657 m (5,440′). It has low TDS (9.4-45.5 micro-Siemens per centimeter) and a weakly acidic pH of 4.2-6.5 (Kownacki and others, 2000). Its chironomid fauna (Insecta: order Diptera, family Chironomidae) are similar to those in the Alps at similar elevations (Kownacki and others, 2000). Although B. paludosa disappeared from the “Dwoisty Staw” lakes before the 1990s, its previous presence indicates that similar ponds in the Alps should be good habitat. B. paludosa is still present in “Wyzny Furkotny” lake in the Slovakia part of the Tatra Mountains (Kownacki and others, 2000).
The problem could be fish stocking.
- “European alpine lakes have been repeatedly stocked for several centuries, in some cases as early as the late 15th century (Monti, 1903; Pechlaner, 1984; Kalchev et al., 2004; Catalan et al., 2006). In many areas, the only lakes without fish are those where fish cannot survive because of particularly extreme conditions . . .” (Catalan and others, 2009).
Alpine charr were documented in mountain lakes of Italy as early as the 1500s (Tiberti and Splendiani, 2019). The nearest definitively native population is in Austria on the north side of the Alps. The Italian mountain lakes with alpine charr were covered by glaciers from 26,500 to 19,000 years ago (Tiberti and Splendiani, 2019). Because glaciers were responsible for the current topography and major river divides of the Alps, it is not clear how fish could have gotten from Austria to Italy after the glaciers began melting.
Although fish-stocking in the Alps started early, the pace accelerated dramatically in the 1900s, particularly after 1960 in the Italian Alps (Ventura and others, 2017). Brown trout and exotic brook trout and rainbow trout are the most common but alpine charr and exotic lake trout have also been stocked. Bait fish, such as minnows, have established populations in alpine lakes, whether intentionally introduced or not. Where surveys have been conducted, almost half of lakes now have fish. In the eastern Alps, 41% of lakes higher than 1,300 m (4,270′) and larger than 0.5 hectare (1.2 acres) have fish. 43% of lakes in the Valle d’Aosta region of Italy which are larger than 0.5 hectare and higher than 1,000 m (3,280′) have fish. Gran Paradiso National Park in western Italy has had 35% of lakes larger than 0.5 hectare contaminated with fish (Ventura and others, 2017). These percentages do not account for the fact that fish can’t survive in many of the highest lakes. The percentages of lakes that could have fish that do have fish are even higher.
The introduction of fish into lakes of the Alps has had a major impact on zooplankton communities. Repeated sampling of 6 lakes with fish and 9 without in Gran Paradiso National Park showed that fish reduced the zooplankton size range from 0.10-3.43 mm in fishless lakes to 0.01-2.08 mm in fishy lakes and eliminated some non-burrowing species, such as water boatmen (Insecta: order Hemiptera, sub-order Heteroptera, family Corixidae) and predaceous diving beetles (Insecta, order Coleoptera, family Dytiscidae) (Tiberti and others, 2014). Some large-bodied cladoceran species (Crustacea: class Branchiopoda, order Anomopoda) persisted but in much lower abundances and only as populations of uncharacteristically small individuals (Tiberti and others, 2014). These results indicate that any fairy shrimp populations would have been eliminated from stocked lakes, as has happened in western North America.
Fairy shrimp may have been largely eliminated from the Pyrenees in a similar fashion. There are documents regarding fishing rights in the Pyrenees that date back to the 1300s and 1400s. 26.5% of lakes on the southern slope of the Pyrenees had fish by 1900 (Ventura and others, 2017). Now, up to 85% of lakes in some valleys have been stocked (Miro and Ventura, 2020). Brown trout alone has been found in 50% of the lakes (Miro and Ventura, 2020). Effects on invertebrate and amphibian communities have been dramatic. Species richness of “conspicuous macroinvertebrates” (i.e., those with large bodies) has been halved in lakes with trout. The percentages of lakes that have amphibians has been reduced from almost 80% for fishless lakes to less than 20% for lakes with fish (Miro and Ventura, 2020). The better documentation of stocking in the Pyrenees suggests the estimates above of lakes with fish in parts of the Alps by Ventura and others (2017) may be best case scenarios. Perhaps well over 50% of the lakes and larger ponds in the Alps of France, Switzerland, Austria, and Germany have been stocked with fish.
There is apparently no information on how many of the stocked lakes in the Alps had fairy shrimp before fish were introduced. Maybe thousands, maybe only a few. In any case, the stocked lakes and any others connected to them by streams have greatly reduced the current potential fairy shrimp habitat. As in the mountains of western North America, the best chance of finding fairy shrimp in the Alps is in small, shallow ponds that are not connected to streams that might have fish.
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One thing that could account for a natural lack of fairy shrimp in the Alps is unfavorable timing of water bird migrations. Water birds found along the European flyway, such as tufted ducks, generally winter in central Europe or, alternatively, around the North Sea (Liu and others, 2012). Almost half a million water birds winter in Switzerland according to the Swiss Ornithological Institute. Most frequent the large lakes north of the Alps, such as Lac Léman (Lake Geneva) (372 m, 1,220′), Lac de Neuchâtel (429 m, 1,410′), and Bodensee (Lake Constance) (395 m, 1,300′), which never freeze over (www.vogelwarte.ch/modx/en/atlas/focus/waterbirds-where-wintering-and-breeding-grounds-overlap). There are plenty of birds in the winter but that’s when the ponds and lakes in the mountains are covered by ice. Because some species, such as tufted ducks, returning from breeding areas in northwestern Russia arrive on the wintering grounds as early as August (Hofer and others, 2005, abstract and captions in English), they could in theory arrive with fairy shrimp eggs before the mountain lakes freeze. However, if they land on the large lakes first, any eggs in their feces will wind up in lowland lakes with fish rather than in the mountains.
In contrast, birds utilizing the eastern Siberian flyway winter in India and breed in central Siberia (Liu and others, 2012). As they fly between their wintering and breeding grounds, they could well drop fairy shrimp eggs off in Tibet, Mongolia, and the Himalaya Mountains, where fairy shrimp are still present.
If unfavorable water bird migration patterns explain the lack of fairy shrimp in the Alps, how did cladocerans (e.g., Catalan and others, 2009) colonize many of the high mountain lakes? Cladocerans also rely on resting eggs for dispersal.
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