Overview

Comprehensive Description

Description

  Common names: chromis (English), damselfish (English), castañeta (Espanol), castañuela (Espanol)
 
Chromis atrilobata Gill, 1862


Scissortail chromis,     Scissortail damselfish


Body compressed, elongate, greatest body depth 2.3-3.7 in SL;  1 pair of nostrils; edge of bone under eye smooth; preopercle smooth or with occasional fine serrations; mouth small, protrusible, opens at front;  teeth in 2 rows, outer conical, larger; lower gill rakers 20-23; a single continuous dorsal fin, XII, 12-13; anal rays II, 10-12; pectoral rays 18-19; 2-3 short projecting spines at upper and lower base of tail fin; caudal fin forked, with sharp tips; scales large and rough; 20-21 lateral line scales; body scaled,  most of head scaled, basal parts of the median fins scaled; lateral line incomplete, ends under end of dorsal fin base.

Metallic grey with prominent white spot just below base of soft dorsal fin; each caudal fin lobe with intensely blackish streak, a blackish mark at base of pectoral fin.


Size: attains 13 cm.

A common species that forms large aggregations around rocky reefs.

Depth: 1-80 m.

Central Baja and the Gulf of California to northern Peru, and all the offshore islands except Clipperton.
   
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Biology

Adults inhabit coral or rocky reefs (Ref. 9334). They aggregate in large numbers in open water above reefs and feed on zooplankton. Not strongly territorial as other damselfishes in the area. They become almost invisible in the darkness of deep water except for its brilliant post-dorsal white spot which gives the illusion of glowing in the dark. Oviparous, distinct pairing during breeding (Ref. 205). Eggs are demersal and adhere to the substrate (Ref. 205). Males guard and aerate the eggs (Ref. 205).
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Distribution

Range Description

This species is endemic to the Eastern Pacific, and is found from central Baja California and the Gulf of California to northern Peru, including the Revillagigedo, Cocos, Malpelo and Galapagos Islands.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Zoogeography

See Map (including site records) of Distribution in the Tropical Eastern Pacific 
 
Global Endemism: All species, East Pacific endemic, Tropical Eastern Pacific (TEP) endemic

Regional Endemism: All species, TEP endemic, Continent + Island (s), Continent, Island (s)

Residency: Resident

Climate Zone: North Temperate (Californian Province &/or Northern Gulf of California), Northern Subtropical (Cortez Province + Sinaloan Gap), Northern Tropical (Mexican Province to Nicaragua + Revillagigedos), Equatorial (Costa Rica to Ecuador + Galapagos, Clipperton, Cocos, Malpelo), South Temperate (Peruvian Province )
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Eastern Pacific: northern Gulf of California to northern Peru, including the Galapagos and Cocos islands.
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Eastern Pacific.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© FishWise Professional

Source: FishWise Professional

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Depth

Depth Range (m): 1 (S) - 80 (S)
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Physical Description

Morphology

Dorsal spines (total): 12; Dorsal soft rays (total): 12 - 13; Analspines: 2; Analsoft rays: 10 - 12
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Size

Length max (cm): 13.0 (S)
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Size

Maximum size: 100 mm SL
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© FishWise Professional

Source: FishWise Professional

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Max. size

13.0 cm SL (male/unsexed; (Ref. 28023))
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Diagnostic Description

Brown with a prominent black spot on the base of the pectoral fin. Fins with thin light blue or white margin.
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Type Information

Type for Chromis atrilobata
Catalog Number: USNM 3675
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Fishes
Collector(s): J. Xantus
Locality: Lower California, Cape San Lucas., Baja California Sur, Mexico, Pacific
  • Type:
Creative Commons Attribution 3.0 (CC BY 3.0)

© Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Fishes

Source: National Museum of Natural History Collections

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
This species inhabits coral or rocky reefs (Allen, 1991) to depths of 80m. At Gulf of Chiriqui, Panamá, this fish could be found in all sites studied over different types of substrata (Dominici-Arosemena and Wolff, 2006). It aggregates in large numbers in open water above reefs and feeds on zooplankton.

Systems
  • Marine
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Environment

reef-associated; non-migratory; marine; depth range 6 - 80 m (Ref. 9334), usually 6 - 20 m (Ref. 6852)
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Depth range based on 26 specimens in 1 taxon.
Water temperature and chemistry ranges based on 2 samples.

Environmental ranges
  Depth range (m): 1.35 - 17
  Temperature range (°C): 22.443 - 24.488
  Nitrate (umol/L): 0.290 - 3.645
  Salinity (PPS): 35.023 - 35.261
  Oxygen (ml/l): 4.879 - 4.879
  Phosphate (umol/l): 0.543 - 0.897
  Silicate (umol/l): 4.062 - 7.763

Graphical representation

Depth range (m): 1.35 - 17

Temperature range (°C): 22.443 - 24.488

Nitrate (umol/L): 0.290 - 3.645

Salinity (PPS): 35.023 - 35.261

Phosphate (umol/l): 0.543 - 0.897

Silicate (umol/l): 4.062 - 7.763
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Depth: 6 - 80m.
From 6 to 80 meters.

Habitat: reef-associated.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© FishWise Professional

Source: FishWise Professional

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Salinity: Marine, Marine Only

Inshore/Offshore: Inshore, Inshore Only

Water Column Position: Bottom, Bottom only

Habitat: Reef (rock &/or coral), Reef only, Rocks, Corals, Reef associated (reef + edges-water column & soft bottom), Flotsam

FishBase Habitat: Reef Associated
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Trophic Strategy

Inhabits coral or rocky reefs (Ref. 9334). Aggregates in large numbers in open water above reefs and feeds on zooplankton. Not strongly territorial as other damselfishes in the area. This fish becomes almost invisible in the darkness of deep water except for its brilliant post-dorsal white spot which gives the illusion of glowing in the dark. Planktivore (Ref. 57615).
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Feeding

Feeding Group: Planktivore

Diet: zooplankton, pelagic fish eggs
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Life History and Behavior

Life Cycle

Oviparous, distinct pairing during breeding (Ref. 205). Eggs are demersal and adhere to the substrate (Ref. 205). Males guard and aerate the eggs (Ref. 205).
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Reproduction

Egg Type: Benthic, Pelagic larva
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage: Chromis atrilobata

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 21
Species With Barcodes: 1
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2010

Assessor/s
Allen, G., Robertson, R., Rivera, R.,Edgar, G., Merlen, G., Zapata, F. & Barraza, E.

Reviewer/s
Carpenter, K., Polidoro, B. & Livingstone, S. (Global Marine Species Assessment Team)

Contributor/s

Justification
This species is widespread in the Eastern Pacific, and is common in many parts of its range. There are no major threats for this species, and no current indication of population decline. It is listed as Least Concern.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

IUCN Red List: Not evaluated / Listed

CITES: Not listed
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Population

Population
This species is considered common or abundant in many parts of its range.

This species was studied in different sites at Galapagos archipelago, with an overall mean abundance of 5.19 ind./500 m2 (Edgar et al. 2004). This fish was studied in Gulf of Papagayo, Costa Rica (Dominici-Arosemena et al. 2005) with a density of 0.68±1.21 ind./ m2. At Gulf Dulce, still in Costa Rica, it had a density of 0.119±0.316 ind./ m2 and a relative abundance of 3.208% (Figueroa, 2001). Within a five-site-study survey, at Catalinas Islands, this fish could be observed in all sites, being the most abundant species; it had 1169 overall observations (Espinoza and Salas, 2005). According to Aburto-Oropeza and Balart (2001), C. atrilobata is a the most dominant species at Los Islotes, Gulf of California and accounted more than 1% of total abundance, with an occurrence frequency higher than 80%. In Cabo Pulmo, Mexico, this fish was considered abundant, more than 5% of the overall abundance registered - with a relative frequency between 25-50% (Villarreal-Cavazos et al. 2000). A survey at Gorgona Island coral reefs, Colombia (Rubio, 1986), showed that this fish seems to be abundant in coralline, sandy bottoms and tide-pools while occasional in rocky bottoms. Zapata and Morales (1997), also in the same place, recorded a density of 51.724±100.536 ind./10 m2, the most abundant species, with an observational frequency of 84.9%.

Population Trend
Unknown
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Threats

Major Threats
There are no major threats known for this species. Populations studied in the Galapagos declined by more than one order of magnitude during the one year period commencing at the start of the 1997/98 El Niño events, but populations had recovered by 2000. No equivalent population changes were observed at Gorgona during the same period (Fernando Zapata, pers obs).

According to Dominici-Arosemena et al. (2005), this is a important aquarium fish in Gulf of Papagayo, Costa Rica, however this probably has an insignificant effect on the population.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Least Concern (LC)
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© FishBase

Source: FishBase

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Management

Conservation Actions

Conservation Actions
There are no known conservation measures for this species. However, this species distribution falls partially into a number of Marine Protected Areas in the Eastern Pacific region (WDPA 2006).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!