Common name: whitetail damselfish
Synonyms and Other Names: whitetail major
available through www.itis.gov
Identification: The whitetail damselfish has an oval compressed body with a bluntly forked caudal fin and moderately large rough scales (Robertson and Allen 2015). Adults are dark brown with darker scale edges, a blue iris, and their pectoral fins have a yellow margin (Robertson and Allen 2015). They often have a whiteish band on the base of the tail fin (Robertson and Allen 2015). Juveniles are overall a purplish-brown grading to yellow from the forehead along the anterior portion of the back up to the end of the spinous dorsal fin (Allen and Woods 1980). They have a dark spot at the rear base of the soft dorsal fin with a white bar across the base of the tail fin (Robertson and Allen 2015).
Size: Up to 11.5 cm standard length (Allen 1991), total length to 17 cm (Allen and Robertson 1994)
Native Range: Whitetail damselfish are found in the tropical Eastern Pacific Ocean. They are common in the Revillagigedo and Guadalupe Islands and found from the southern Gulf of California to Mazatlán, Mexico (Allen 1991).
Individuals were observed at Santa Catalina Island, California in 2012, 2015 (Love et al. 2016), and 2019. Other 2015 sightings in California include San Clemente Island and La Jolla Shores (Love et al. 2016). Several young of the year were observed in 2015 at Coronado Islands, Mexico (Love et al. 2016). Whitetail damselfish were documented in Magdalena Bay, Mexico in 2014 (Hernández-Velasco et al. 2016).
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Stegastes leucorus are found here.
Table last updated 2/8/2023
† Populations may not be currently present.
Ecology: This species inhabits shallow rocky reefs (Allen 1991). They are omnivores and feed on benthic crustaceans, worms, and algae (Robertson and Allen 2015).
Reproduction: Breder and Coates (1933) observed a breeding pair in captivity carrying several mouthfuls of sand to potential egg laying sites. The fish blew the sand out and vigorously fanned the site effectively sand blasting the surface until cleaned. The female then laid concentric circles of eggs that were fertilized by the male and tended by both parents. They estimate 400-500 eggs were laid.
Means of Introduction: Probably a waif from the native range.
Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.
An adult as well as juveniles were observed defending reef territory against native Garibaldi damselfish, Hypsypops rubicundus (Love et al. 2016).
References: (click for full references)
Allen, G.R. 1991. Damselfishes of the World. Mergus Publishers, Germany.
Allen, G. R. and Robertson, D.R. 1994. Fishes of the tropical eastern Pacific. University of Hawaii Press, Honolulu.
Allen, G., Robertson, R., Zapata, F. 2010. Stegastes leucorus. The IUCN Red List of Threatened Species 2010: e.T183963A8207287. http://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T183963A8207287.en. Downloaded on 19 August 2019.
Breder, C.M. and Coates, C.W. 1933. Reproduction and eggs of Pomacentrus leucoris Gilbert. American Museum Novitates 612:1-6.
Hernández-Velasco, A., Fernández-Rivera-Melo, F.J., Melo-Merino, S.M., and Villaseñor-Derbez, J.C. 2016. Occurrence of Holacanthus clarionensis (Pomacanthidae), Stegastes leucorus, and Stegastes acapulcoensis (Pomacentridae) at Magdalena Bay, B.C.S., Mexico. Marine Biodiversity Records 9:49.
Love, M.S., Bushing, W.W., and Power, W. 2016. The whitetail damselfish (Family Pomacentridae), Stegastes leucorus (Gilbert, 1892), new to California marine waters with a key to the California species of Pomacentridae. Bulletin of the Southern California Academy of Sciences 115(2): 136-139.
Robertson, D.R. and Allen, G.R. 2015. Shorefishes of the tropical Eastern Pacific: online information system. Version 2.0 Smithsonian Tropical Research Institute, Balboa, Panama. https://biogeodb.stri.si.edu/sftep/en/pages.
Brown, M.E., and Schofield, P.J.
Revision Date: 9/30/2019
Peer Review Date: 9/30/2019
Brown, M.E., and Schofield, P.J., 2023, Stegastes leucorus (Gilbert 1892): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=3331, Revision Date: 9/30/2019, Peer Review Date: 9/30/2019, Access Date: 2/8/2023
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.