Banggai cardinalfish

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Banggai cardinalfish
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Kurtiformes
Family: Apogonidae
Subfamily: Apogoninae
Genus: Pterapogon
Species:
P. kauderni
Binomial name
Pterapogon kauderni
Koumans, 1933

The Banggai cardinalfish (Pterapogon kauderni) is a small tropical cardinalfish in the family Apogonidae. It is the only member of its genus.[2] This attractive fish is popular in the aquarium trade. It is among the relatively few marine fish to have been bred regularly in captivity, but significant numbers are still captured in the wild and it is now an endangered species. The detrimental impact of humans on its environment and certain fatal diseases threaten this species' numbers significantly. Iridovirus diseases are known to be significant reason for fish mortality.

Distribution

In the wild, Lembeh Straits, North Sulawesi, Indonesia.

This species is restricted to the Banggai Islands of Indonesia.[3] This species has an extremely limited geographic range (5,500 km2) and small total population size (estimated at 2.4 million).[4] The Banggai cardinalfish is composed of isolated populations concentrated around the shallows of 17 large and 10 small islands within the Banggai Archipelago. A small population also occurs off Central Sulawesi, within Luwuk harbor. One additional population has become established in the Lembeh Strait (North Sulawesi), 400 km north of the natural area of the species distribution, following introduction by aquarium fish traders in 2000.[4] Small populations seen (May 2014) in Secret Bay, north west Bali (Banggai cardinal fish, Secret Bay, Bali)

Description

This species grows up to 8 

caudal fin, and color pattern consisting of three black bars across the head and body and prominent black anterior edges on the anal and second dorsal fin.[4] The male can be differentiated from the female by a conspicuous, enlarged oral cavity, which is apparent only when they are brooding.[4]

Ecology

The Banggai cardinalfish is the only member of its family that is diurnal.

anemone shrimp when sheltering in anemones and corals; when found among sea urchin spines, it associates with several other genera of cardinalfish. Following removal of the fish by aquarium collectors, the abundance of associated invertebrates has been shown to decline.[4]

This fish is an opportunistic feeder. Its diet includes planktonic, demersal, and benthic organisms.

yellow-lipped sea krait (Laticauda colubrina).[4]

The Banggai cardinalfish is a paternal mouthbrooder.[4] The female plays an active role in courtship and pair formation, which occurs a few hours to a few days before spawning. Mating pairs establish spawning territories several meters away from the main group and vigorously defend them.[4] The eggs are about 2.5 mm in diameter. The young remain in the male's mouth cavity for an undetermined period after hatching.[3] Unlike many other species of marine fish, the Banggai cardinalfish lacks a planktonic stage in its life history.[4] The species has a short lifespan, reaching around 4 years in optimal conditions in captivity, and perhaps 1 to 2 years in the wild.[4]

In captivity

Budapest Zoo
aquarium

The Banggai cardinalfish is a popular aquarium fish among fishkeepers.

The fish is collected by local fishers and sold into the aquarium trade. This species first appeared in the international trade around 1995 or 1996. By 2001, 600,000 to 700,000 fish were exported annually. Trade estimates for 2001 through 2004 are 700,000 to 900,000 fish per year with collection occurring throughout the archipelago. Surveys identified significant (>90%) declines in two populations that were fished from 2001 to 2004, including the extinction of a population off of Limbo Island.[4]

This fish has been successfully bred in captivity.[3] Captive breeding presents an alternative to wild-caught fish. Initially, the relatively high cost–benefit ratio of its production combined with the large number of less expensive wild-harvested fish prevented expansion of aquaculture efforts. In recent years, prices for captive bred or aquacultured specimens have plummeted as large numbers have entered the market. As of early 2018 aquacultured individuals are regularly available for as little as $14 U.S. per fish, and aquacultured specimens make up the vast majority of the market. In addition, a newly emerging threat in the form of a viral disease has been documented in wild-harvested individuals maintained in captivity.[4]

Collection for the aquarium trade has threatened this species with

IUCN based on its small range, the fragmentation of its distribution, and its continuing decline due to exploitation for the international aquarium trade.[1] In 2007, the species was proposed to be listed for protection under CITES Appendix II, which could limit export of wild-caught individuals, but Indonesia would not support this, and the proposal was withdrawn.[5]

Breeding

Life cycle

Banggai cardinalfish are sexually monomorphic.[6] The pairs form up to 2 weeks prior to spawning. The female courts the male from pair formation until spawning.[7] The female's size determines the fecundity and egg size, but the male's size determines the reproductive output, or the number of the eggs that the pair produces.[7] Therefore, pairing tends to occur among individuals of similar sizes, so the male is able to care for all the eggs that the female produces.[6]

Courtship

In Banggai cardinalfish, courtship behavior is usually initiated by the female. Upon choosing a mate, the female isolates her potential mate from other individuals in the colony by creating a spherical spawning site that is about 50–60 cm in diameter.

anal fins come into contact.[8] The female repeats this movement until the male responds with sporadic 'mouth opening,’ a sign of receptiveness. Such courtship behavior may last from several hours to 2–33 days.[8] When an intruder interrupts a female's courtship behavior, the female would rapidly and aggressively chase the intruder away if the intruder is of the same sex.[8] However, when the secondary male, or the intruder male approaches, he, instead of the female, exhibits trembling behavior, and also helps to defend the female and primary male's isolated territory.[8] If the primary male does not respond to female's trembling, the female leaves periodically to visit the secondary male and displays trembling behavior which often results in mating.[8]

Selection of mates

Although the females initiate

brood its eggs.[7]
Male Banggai cardinalfish also exhibit preference by size, as larger females tend to lay larger eggs, and egg size positively affects traits such as offspring size, survival, growth, time until maturation, and swimming performance.
spawning the female is.[10] By forming a pair with a female with more mature eggs, or closer to spawning, a male can increase his reproductive rate. Furthermore, he can match his readiness to spawn to females' by observing her 'twitch' behavior.[10]

Reproduction

Spawning

When the male accepts female courting, the female expels eggs from her urogenital papilla. Female Banggai cardinalfish produce a relatively small clutch, consisting of no more than 90 eggs that are 2–3 mm in diameter.[10] Once about three-fourths of the egg mass protrudes from the female, the male takes the eggs from her. This process is immediate, taking no more than 2 seconds.[8] Eggs may be lost in the process if the male drops them, as they are usually immediately consumed by other fish in the area.[8] Males also have the ability to detect dead eggs and expel them from their mouths.[8] The male broods the eggs in his mouth up to 30 days, during which he does not feed.[7] After spawning, the female stays with the brooding male for at least a few days.[9] Females aggressively defend their territory by immediately chasing any intruders that approach the brooding males. They also exhibit a relaxed form of 'side-by-side trembling', and confine the males to a small space.[8]

Juvenile behavior

Juvenile Banggai cardinalfish do not go through any

anemones, and swim around together while the father does not exhibit much caring behavior.[8][13]

Grouping

Banggai cardinalfish live in shallow lagoons in groups that include up to 500 individuals. They are often found near sea urchins, where the fish hide when threatened.

microhabitats around which the cardinalfish group.[12] These groups of fish are rather sedentary, and movements between groups are observed to be very limited, especially because they feed on plankton that pass through water currents.[12][14] Such limited dispersal of Banggai cardinalfish prevents them from spreading over large geographic ranges, thus serving as a major risk of extinction along with heavy exploitation by aquarium fish collectors, as well as low fecundity.[13][15]

Gallery

References

  1. ^
    doi:10.2305/IUCN.UK.2007.RLTS.T63572A12692964.en
    . Retrieved 19 November 2021.
  2. PMID 25112246
    .
  3. ^ a b c d e f Froese, Rainer; Pauly, Daniel (eds.) (2015). "Pterapogon kauderni" in FishBase. August 2015 version.
  4. ^ a b c d e f g h i j k l m n o p q Consideration of Proposals for Amendment of Appendices I and II. Convention on International Trade in Endangered Species of Wild Fauna and Flora. Fourteenth meeting of the Conference of the Parties. The Hague. 3–15 June 2007.
  5. ^ Vagelli, A. A. (2008). "The unfortunate journey of Pterapogon kauderni: A remarkable apogonid endangered by the international ornamental fish trade, and its case in CITES" (PDF). SPC Live Reef Fish Information Bulletin. 18: 17–28.
  6. ^
    S2CID 53194035
    .
  7. ^
    doi:10.1111/j.1095-8649.2003.00205.x
    .
  8. ^
    S2CID 6885266
    .
  9. ^
    S2CID 42705233
    .
  10. ^
    S2CID 19317028
    .
  11. ^
    S2CID 86018802
    .
  12. ^
    S2CID 39885519
    .
  13. ^
    S2CID 38435909
    .
  14. ^
    doi:10.1093/beheco/ari022
    .
  15. S2CID 38161941
    .

External links

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