Banggai Cardinal Declared Endangered

From Microcosm Aquarium Explorer

Pterapogon kauderni 1 SS.jpg

Banggai Cardinalfish mixed-age shoal. Alf J. Nilsen/Bioquatic

Overzealous Collection for the Aquarium Trade is Blamed for Threat to Survival of the Wild Banggai Cardinalfish

Barely more than a decade after being introduced to the marine aquarium trade, the elegant Banggai Cardinalfish (Pterapogon kauderni) has been placed on the IUCN Red List as an Endangered Species.

Ironically, the assessment done for the World Conservation Union, publishers of the Red List, was carried out in part by Dr. Gerry Allen. Dr. Allen, with underwater photographer and well-respected marine naturalist Roger Steene, in 1992 presented their discovery of the species in a remote area of Indonesia, triggering intense interest in the aquarium hobby.

Unlike most marine fish species, the Banggai Cardinalfish is confined to a relatively small area in the wild and has been very vulnerable to overcollection.

Concerned aquarists are urging captive breeders to create local supplies of aquacultured Banggai Cardinals, mouthbrooders that have been referred to as the "guppies" of marine fishes for the ease with which they are bred. In turn, hobbyists are asked to seek out captive-bred Banggais, which have a much better survival record than imported wild stock.

An attempt by the United States to have trade in this species controlled by a CITES classification failed earlier in 2007. There is currently no restriction on trade of Pterapogon kauderni.

Text of the IUCN assessment:

Justification

Juvenile Banggai Cardinalfish.

The Banggai Cardinalfish, Pterapogon kauderni, is a small reef fish endemic to the Banggai Islands off Sulawesi, Indonesia. This species is distinguished by having a relatively small population size, limited distribution (EOO about 5,500 km, AOO about 34 km² and it has two distinct geographic clades and one small subpopulation introduced accidentally to Sulawesi), plasticity and ontogenetic differences in microhabitat utilization, a social system based upon group living, territorial behavior in both males and females, paired courtship and spawning that is initiated by females, low fecundity, considerable investment in energy resources for reproduction, paternal oral incubation of eggs and free-living embryos, a lack of a pelagic larval phase, limited dispersal capability and localized settlement and recruitment.

Decline Rates

Several subpopulations affected by the aquarium fishery exhibited dramatic declines between 2001 and 2004, among them: a complete extinction of a subpopulation was documented off Limbo Island in 2004. According to a 2001 census this subpopulation was composed of about 50,000 fish (densities = 0.02 fish/m²); and a small subpopulation off Bakakan Island that harbored 6,000 fish in 2001 was reduced to 17 individuals in 2004 (Vagelli 2005).

The rate of decline for this species is difficult to calculate, since the earliest quantitative surveys (2001) were carried out several years after the harvest began within its natural geographic range. However, one subpopulation localized inside a bay in Southwest Banggai Island has been off limits to all fishing since before the beginning of the trade (the bay is privately owned by a pearl farm business). The bay has the typical habitats, microhabitats, and oceanographic characteristics in which P. kauderni is found throughout the Archipelago, and therefore this subpopulation may be used to estimate what the historical baseline abundance for this species could have been. The density of this subpopulation was 0.63 individuals/m).

This density is significantly higher than the mean density (0.07 individuals/m²) of the eight censuses completed in 2004 in unprotected sites [S = 0.05; highest d= 0.21 (Bokan); lowest d= 0.028 (Bangkulu)]. In addition, a census was carried out about 300 m from the protected bay and the density was 0.071 ind./m² (Lunn and Moreau 2004, Vagelli 2005). If the 0.63 density value is considered as the historical normal density for this species within the Archipelago, then a reduction of approximately 89% took place since the start of the fishery (about 9 to 10 years before the 2004 censuses).

Local Bans Trigger Rebounding Effects

However, at one of these sites (Masoni) the density increased from 0.03 to 0.06 individuals/m² between 2001 and 2004. This increase is thought to have occurred in response to a collecting ban that the local people imposed in early 2003. In another site (Bokan) a more significant increase was found in 2004, i.e., 0.21 individuals/m². In this case too, collection in the census site (which has an area of occupancy of only about 1 km²) was banned in 2002 by the village chief because of disputes with outside collectors (Vagelli 2005).

The size class structure of populations found during the last survey (2004) within the natural range of P. kauderni, agree with those reported previously, where most fish encountered were large juveniles (6 to 9 months old), whereas newly released recruits (<15 mm TL) are rare (Vagelli and Erdmann 2002). Thus, in 2004 of a total of 3,672 individuals censused, within the Archipelago, 1,364 (37.1%) were adults, 2,140 (58.3%) were older juveniles and 168 (4.6%) new recruits and small juveniles up to about 2 months of age (Vagelli 2005).

Assessment

The decline information is not sufficient to apply Criterion A and likewise Criteria C and D cannot be used because the population is too large. However, based on the very small area of occupancy (AOO), the severe fragmentation (see the documentation below) and the ongoing continuing decline (local extirpations and marked decrease in population size in recent years) due to exploitation for the international aquarium trade, this species is assessed as Endangered under Criterion B.

From the IUCN Red List Assessment by Allen, G.R & Donaldson, T.J.

Full text: http://www.iucnredlist.org/search/details.php/63572/summ


Species Profile: Banggai Cardinalfish