FWS Focus

Overview

Characteristics
Overview

The Conservancy fairy shrimp is a small, freshwater crustacean named for The Nature Conservancy, an organization that has protected several vernal pool ecosystems in California that support the species. Conservancy fairy shrimp are restricted to vernal pools found in Californiaโ€™s Central Valley from Tehama County in the north to Merced County in the south. However, there is one outlying population in Ventura Countyโ€™s Interior Coast Ranges. The Conservancy fairy shrimp was listed as endangered September 19, 1994.

Threats facing the species include:

  • Habitat loss, fragmentation and degradation from development and agriculture
  • Poor grazing practices
  • Non-native plants and grasses
  • Climate change and drought
  • Pesticides

Scientific Name

Branchinecta conservatio
Common Name
conservancy fairy shrimp
FWS Category
Crustaceans
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Similar Species

Characteristics
Similar Species
Characteristic category

Habitat

Characteristics
Habitat

Conservancy fairy shrimp are extremely rare and only found in Californiaโ€™s Central Valley. They mostly live in relatively large, turbid freshwater vernal pools called playa pools. Currently, the U.S. Fish and Wildlife Service is aware of 10 populations of Conservancy fairy shrimp:

  • Vina Plains, Butte and Tehama counties
  • Sacramento National Wildlife Refuge, Glenn County
  • Mariner Ranch, Placer County
  • Yolo Bypass Wildlife Area, Yolo County
  • Jepson Prairie, Solano County
  • Mapes Ranch, Stanislaus County
  • University of California, Merced, Merced County
  • Grasslands Ecological Area, Merced County
  • Sandy Mush Road, Merced County
  • Los Padres National Forest, Ventura County

Conservancy fairy shrimp have been found at elevations ranging from 16 to 5,577 feet (5 to 1,700 meters) above sea level. The species has been found at sites that are low in alkalinity that range from 16 to 47 parts per million.

Grassland

Land on which the natural dominant plant forms are grasses and forbs.

Rural

Environments influenced by humans in a less substantial way than cities. This can include agriculture, silviculture, aquaculture, etc.

Wetland

Areas such as marshes or swamps that are covered often intermittently with shallow water or have soil saturated with moisture.

Characteristic category

Food

Characteristics
Food

Conservancy fairy shrimp are opportunistic filter feeders. They eat algae, bacteria, protozoa, rotifers and bits of waste from other plants and animals present in their environments. They face competition from other fairy shrimp species and Western spadefoot toad tadpoles.

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

They have slender bodies; large, stalked compound eyes and 11 pairs of swimming legs. They glide gracefully through the water upside down, swimming by beating their legs in a complex, wavelike movement that passes from front to back. The Conservancy fairy shrimp can be differentiated from other fairy shrimp by the flattened portions of its antennae. Unlike other types of shrimp, the Conservancy fairy shrimp does not have a hard outer shell.

Measurements
Length: 0.6 to 1.1 in (14 to 27 mm)

Characteristic category

Life Cycle

Characteristics
Life Span

The life span of the Conservancy fairy shrimp is about 114 days. Conservancy fairy shrimp can be found in vernal pools starting in November most years and complete their entire life cycle by April. On average, Conservancy fairy shrimp take 37 days to mature after hatching and 46 days to reproduce. Multiple cohorts of eggs may hatch in a single vernal pool throughout the wet season given the right conditions. Conservancy fairy shrimp disappear before the vernal pools dry.

Conservancy fairy shrimp are non-migratory and have little ability to disperse on their own. Aquatic birds are the most likely agents of dispersal of Conservancy fairy shrimp. Large mammals are also known to act as distributors by wallowing in dirt, getting cysts caught in their fur and transporting the cysts to another wallow. Additionally, cysts can be ingested, passed through the digestive tract and then deposited in new habitats when the animal urinates.

Reproduction

Female fairy shrimp carry fertilized eggs in a sac on the underside of their body. The eggs are either dropped to the pool bottom or remain in the brood sac until the mother dies and sinks to the bottom of the pool.

When the pool dries out, so do the eggs. Resting fairy shrimp eggs are known as cysts. Cysts may remain viable for multiple years due to their protective coverings that help them withstand extreme environmental conditions and even digestion by predators. The cysts remain in the dry pool bed until hatching begins in response to rains and the return of water in the vernal pools.

Geography

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Timeline

Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.

18 Items

Listing

Listing

Listing

Listing

Critical Habitat

Notice

NEPA - EIS

Notice

Notice

Critical Habitat

Recovery Plan

Critical Habitat

Critical Habitat

Five Year Review

Five Year Review

Five Year Review

Five Year Review

Five Year Review

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Listing

Aug 30, 1991

Aug 30, 1991 Listing (Substantial)
ETWP; 90-Day Findings and Commencement of Status Reviews for Three Petitions to List Seven Species aโ€ฆ
  • Publication type: 90 day petition finding
Item 1

Listing

May 8, 1992

May 8, 1992 Listing (Endangered)
ETWP; Proposal to Determine Endangered Status for four Fairy Shrimp and The Vernal Pool Tadpole Shriโ€ฆ
  • Publication type: Proposed
Item 2

Listing

May 8, 1992

May 8, 1992 Listing (Warranted)
ETWP; Proposal to Determine Endangered Status for four Fairy Shrimp and The Vernal Pool Tadpole Shriโ€ฆ
  • Publication type: 12m petition finding
Item 3

Listing

Sep 19, 1994

Sep 19, 1994 Listing (Endangered)
ETWP; Determination of Endangered Status for the Conservancy Fairy Shrimp, Longhorn Fairy Shrimp, anโ€ฆ
  • Publication type: Final
Item 4

Critical Habitat

Sep 24, 2002

Sep 24, 2002 Critical Habitat
Endangered and Threatened Wildlife and Plants; Critical Habitat Designation for Four Vernal Pool Cruโ€ฆ
  • Publication type: Proposed
Item 5

Notice

Oct 10, 2002

Oct 10, 2002 Notice
Endangered and Threatened Wildlife and Plants; Critical Habitat Designation for Four Vernal Pool Cruโ€ฆ
  • Publication type: Public Hearing
Item 6

NEPA - EIS

Nov 4, 2002

Nov 4, 2002 NEPA - EIS
Fish and Wildlife Service, Interior:Draft Environmental Impact Report/Environmental Impact Statementโ€ฆ
  • Publication type: Draft
Item 7

Notice

Nov 21, 2002

Nov 21, 2002 Notice
Critical Habitat Designation for Four Vernal Pool Crustaceans and Eleven Vernal Pool Plants in Califโ€ฆ
  • Publication type: Comment Period Reopening
Item 8

Notice

Mar 14, 2003

Mar 14, 2003 Notice
Endangered and Threatened Wildlife and Plants; Critical Habitat Designation for Four Vernal Pool Cruโ€ฆ
  • Publication type: Comment Period Reopening
Item 9

Critical Habitat

Aug 6, 2003

Aug 6, 2003 Critical Habitat
Endangered and Threatened Wildlife and Plants; Final Designation of Critical Habitat for Four Vernalโ€ฆ
  • Publication type: Final
Item 10

Recovery Plan

Nov 18, 2004

Nov 18, 2004 Recovery Plan (Document Availability (non-FR))
Draft Recovery Plan for Vernal Pool Ecosystems of California and Southern Oregon
  • Publication type: Draft
Item 11

Critical Habitat

Aug 11, 2005

Aug 11, 2005 Critical Habitat
Endangered and Threatened Wildlife and Plants; Final Designation of Critical Habitat for Four Vernalโ€ฆ
  • Publication type: Final
Item 12

Critical Habitat

Feb 10, 2006

Feb 10, 2006 Critical Habitat
Final rule; administrative revisions - Designation of Critical Habitat for Four Vernal Pool Crustaceโ€ฆ
  • Publication type: Final
Item 13

Five Year Review

Mar 22, 2006

Mar 22, 2006 Five Year Review (Information Solicitation)
Initiation of 5-Year Reviews of 56 Species in California and Nevada: Notice of review.
  • Publication type: Notice
Item 14

Five Year Review

Mar 5, 2008

Mar 5, 2008 Five Year Review (Completion)
Initiation of 5-Year Reviews of 58 Species in California and Nevada; Availability of Completed 5-Yeaโ€ฆ
  • Publication type: Notice
Item 15

Five Year Review

May 25, 2011

May 25, 2011 Five Year Review (Information Solicitation)
Initiation of 5-Year Reviews of Species in California, Nevada, and the Klamath Basin of Oregon
  • Publication type: Notice
Item 16

Five Year Review

Apr 1, 2013

Apr 1, 2013 Five Year Review (Completion)
Initiation of 5-Year Reviews of 56 Species in California and Nevada; request for information
  • Publication type: Notice
Item 17

Five Year Review

May 20, 2021

May 20, 2021 Five Year Review (Information Solicitation)
Initiation of 5-Year Status Reviews of 76 Species in California and Nevada; request for information
  • Publication type: Notice
Item 18