The Banggai Cardinalfish has eight dorsal spines, 14 dorsal soft rays, two anal spines, and 13 anal soft rays (Koumans 1933). This species is distinguished further by having a tasseled first dorsal fin and a deeply forked caudal fin. Both the second dorsal fin rays and anal fin rays are elongate. The colour pattern is quite distinctive with three black bars across the head and body, black edges along the anterior margins of the second dorsal and anal fins, black edges along the upper and lower margins of the caudal fin, and black pelvic fins marked with white spots. A series of similar white spots run along the edges of the second dorsal, anal and caudal fins (Allen and Steene 1995, Allen 2000). The body is silvery and contains about 20 brilliant whitish dots between the second and third black bars. Dots of each individual have a unique disposition that can be used for specimen identification (Vagelli 2002). Body size of adults reaches 80 mm total length and 55 mm standard length (SL) (Allen 2000). Secondary sexual dimorphism has not been demonstrated for this species (Vagelli and Volpedo 2004).

The genus Pterapogon contains only one other species, P. mirifica from northwestern Australia. However, ongoing studies on the reproductive biology, behaviour, anatomy and preliminary data on molecular studies on P. mirifica (A. Vagelli, pers. comm. on 27th Feb 2007) indicate that it is distantly related to the Banggai Cardinalfish and may in fact merit separate generic status. Therefore the Banggai Cardinalfish may be unique at the generic level.

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 km², 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/m²).

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).

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.

Pterapogon kauderni is a rare example of a marine fish with an extremely limited geographic range. It is endemic to the Banggai Archipelago, which lies in the Banggai-Sula platform in eastern Indonesia. The Banggai Island group is thought to have been a geological entity during the Cenozoic, and is located within the region of Wallacea. The natural geographic range of P. kauderni extends from 01° 24' 57.6" of latitude South (Monsamat, east Peleng) as its northern most distribution point to 02° 0' 53.5" of latitude South (Loisa A), and from 123° 34' 11" of longitude East (Patipakaman, central Peleng) as its westernmost distribution to approximately 124° 23' 30" of longitude East (Kano) and the south-east tip of Taliabu. This distribution covers an area of approximately 5,500 km². However, within this range, the maximum potential available habitat is about 426 km of coastline extending from the shore to about 100 m off the coast, with a maximum available area of about 34 km² (Vagelli 2005).

P. kauderni was found in 74 sites in 30 islands. Four sites were located in the Lembeh Strait (three islands and Sulawesi) in north Sulawesi, where this species was introduced in 2000, and in one site in central Sulawesi (Luwuk). The rest of sites were located within its natural distribution, i.e., the Banggai Archipelago. Here, it was found in 17 of the 20 major islands and in 10 of the 27 minor islands.

The most isolated subpopulation inhabiting a large island was located in the eastern coast of Tempaus, which is separated from the subpopulation inhabiting Masoni Island by 16 km, and towards the west the closest subpopulation is found in south Bokan, at about 30 km. The second most isolated subpopulations inhabit Bangkulu Island, with its north subpopulation separated by about 13.6 km from south Peleng, and by about 13.5 km from Labobo Kenecil. Then, the subpopulation inhabiting Masoni Island is separated by about 11 km from the subpopulation located in Limbo, and by 16 km from that inhabiting Tempaus. Finally, the subpopulation found in Labobo is separated by about 10 km from the subpopulation located in Bangko and by 13.6 km from the closet subpopulation inhabiting Bangkulu. All other large islands are inhabited by at least one subpopulation of P. kauderni that is separated by no more than (and frequently less) 5 km from another subpopulation inhabiting a different large island. Despite that oceanographic and physiographic conditions, as well as availability of habitats and substrates were similar to those found on big islands inhabited by P. kauderni, no populations of P. kauderni were found in the other 17 minor islands, reefs and atolls located far from the big islands. Furthermore, some of these small islands were separated by very short distances from big islands inhabited by P. kauderni. Thus, no subpopulation of P. kauderni was found in Tanalan (localized at only 3.7 km from the subpopulation inhabiting Masepe), Belangan (at 2 km from the population of Bokan), Bongko (at 3.7 km from the subpopulation of north Bangkulu), Sidula (at 5 km from the subpopulation inhabiting center-east Bangkulu), Togonglantan (separated by 5 km from the subpopulation of Bangkulu and by 6 km from that in habiting Labobo), nor in Tabija, which lays at only 1.5 km from the P. kauderni subpopulation inhabiting the bay localized south of Keya on the nor-occidental coast of Taliabu.

The Luwuk subpopulation, whose origin is not clear, is restricted to a very small area inside the harbor and is exposed to high levels of pollution and contaminants. Despite thorough searching from the harbour mouth to as far north as Botok (68 km), and as far south as Luk (46.5 km), no populations of P. kauderni were found outside the harbour, despite that environmental conditions and substrate availability were much better than those inside the harbor. The closest subpopulation of P. kauderni to the one at Luwuk is located about 100 km southeast, in Patipakaman (Peleng Island).

The Lembeh subpopulation is located about 400 km north of the natural range of P. kauderni natural range; it was first detected in the Lembeh Strait in September 2000 occupying an area of approximately 50 m along the coast of Sarina Kenecil Island. The establishment of this subpopulation is a consequence of accidental or intentional releases from an aquarium fish operation in the area. By November 2000 this subpopulation expanded to the "Police Pier" on the margin of Sulawesi, where by May 2001 about 650 individuals occupied an area of approximately 750 x 250 m. By April 2004, P. kauderni extended its range from the Police Pier to at least 200 m to the south, and at least 500 m to the north. In addition, it was found for the first time in Sarina Island, and in Lembeh Island, where it was introduced in 2002 (Erdmann and Vagelli 2001, Vagelli and Erdmann 2002, Vagelli 2005).

See distribution map, and maps in the attached PDF.

The earliest known population survey (2001) identified P. kauderni on 16 out of 37 islands searched. Average densities in suitable habitat at three sites within the Banggai Archipelago were approximately 0.03 fishes per m² (Vagelli and Erdmann 2002). Based on these census data and calculations of the total available habitat, the species was estimated to have a total population size of 1.7 million fish (Vagelli 2002). Additional surveys in 2002 and 2004 covering the entire Archipelago (50 islands, 159 sites) expanded the range to 27 (17 major and 10 minor) islands. Surveys done in 2004 found P. kauderni in most sites at densities of about 200 to 700 individuals/ha. The mean density based on census carried out in seven locations throughout its natural range in 2004 was 0.07 individuals per m², with a total population size estimated at 2.4 million individuals (Vagelli 2005).

P. kauderni exhibits the highest degree of population structure that has been documented for a marine fish (Hoffman et al. 2005). This is a unique case of genetic isolation in populations separated by extremely short distances. Studies utilizing both mt DNA and micro-satellites have already indicated that populations occurring on reefs of the same islands, separated by only a few kilometers, are genetically isolated from one another (Bernardi and Vagelli 2004). For instance, assignment tests performed in 23 subpopulations from all over the Archipelago, showed that 20 had a significant self-reassignment. When considering all the Bangkulu populations, 94% of the individuals from this island were reassigned back to the island - range 80.0% to 100% (Vagelli et al. in prep.). The lack of suitable habitats between subpopulations coupled with lack of dispersal mechanisms, are the most likely reasons for this isolation.

Banggai Cardinalfish populations are distinguished for having two monophyletically-distinct clades: a southwestern clade restricted to the southwest of Bangkulu Island, and northern and eastern clades distributed throughout the remainder of its range (Bernardi and Vagelli 2004). Eleven polymorphic tetranucleotide microsatellite loci have been isolated from male fishes; polymorphism ranges from 2 to 15 alleles and expected heterozygosities range from 0.107 to 0.928, thus allowing for genetic studies of this species with very high resolution (Hoffman et al. 2004).

Generation length is estimated at being 1.0 years (FishBase 2004), however more recent estimates place it at 1.5 years (A. Vagelli, pers. comm. on 27th Feb 2007).

Habitat:
The Banggai Cardinalfish occurs primarily on shallow sheltered bays and harbors, mainly on silty reef flats with sandy bottoms and sea grass beds. Depth distribution is generally ranges between 0.5 and 6 m, but is most commonly found between 1.5 and 2.5 m. Some populations inhabit very clear waters in coral reef areas, while others inhabit still, murky bays, and some groups are found in sandy patches associates with anemones, and less commonly, in open habitats (low branching corals and rubble). This species inhabits a variety of shallow habitats, including coral reefs (51% of identified groups), seagrass beds (35%), and open areas of sand and rubble (14%). It is most common in calm habitats on the protected side of larger islands; isolated populations also occur in areas affected by strong surge and moderate currents Water temperatures in these habitats range from 28°C to 33°C (Vagelli and Erdmann 2002, Vagelli 2005). There is an ontogenetic shift in habitat and microhabitat use between juveniles and adults that occurs within the same area and depth; all size classes, including mating pairs and brooding males, overlap in their distribution; the shift in use is not the consequence of differential feeding habitats nor intraspecific competition (Vagelli 2004a). The processes governing this ontogenetic shift are not clear. No pre-settlement factor is involved, however, because this species lacks a pelagic larval phase and embryos released by brooding males settle into parental habitat directly (Vagelli 1999, 2002, 2004a; Vagelli and Volpedo 2004).

Juveniles associate with sea grasses, sea urchins, sea stars, sea anemones, soft corals and corals. Adults shelter between the spines of sea urchins but also among anemones, corals, stony hydrozoans, rocks and artificial structures such as jetties (Allen 2000, Vagelli and Erdmann 2002, Vagelli 2004a). Sea anemones utilized include Actinodendron sp., Entacmaea quadricolor, Heteractis crispa, Macrodactyla doreensis, Stichodactyla haddoni, and S. merteensis. Corals include Acropora sp., Anacropora sp., Echinopora horrida, Goniopora sp., Heliofungia actiniformis, Montipora digitata and Seriotopora hystrix. Soft corals utilized include Nephthea sp. and stony hydrozoans include Millepora sp. Sea urchin species utilized include Diadema setosum and Tripneustes sp., while the sea star is Proteaster nodosus. Banggai Cardinalfishes also associate with the submerged roots of mangroves (Rhizophora sp.). Census work showed that 43.7% of the groups were associated with hard corals, 31.9% with urchins Diadema setosum, and 24.4% with anemones (Allen 2000; Vagelli and Erdmann 2002; Vagelli 2004a, 2005).

Ecology:
When sheltering in anemones and Heliofungia corals, P. kauderni often associates with various species of anemone fishes (Amphiprion) and anemone shrimps (Periclimenes), and with several species of Apogonidae (Apogon, Archamia, Cheilodipterus and Sphaeramia when living among spines of sea urchins. In seagrass beds (predominantly composed of Enhalus acoroides), P. kauderni is associated with anemones, isolated live corals, sea urchins or sea stars forming small fish assemblages, commonly with Abudefduf sexfasciatus and several species of Pomacentrus, Chromis and Halichoeres.

Diet:
As opposed to other described apogonids, P. kauderni has diurnal trophic habits, and its feeding activity decreases with the day and ceases around sunset time. P. kauderni is a carnivore-planktivore that feeds principally upon copepods, but it is also a generalist opportunistic species that feed upon a variety of taxa, principally planktonic demersal and benthic organisms. Stomach content analysis found prey representing 29 taxa with a taxonomic level of suborder or higher belonging to 6 phyla: Rhyzopoda, Annelida, Mollusca, Arthropoda, Chaetognatha, and Chordata. There were no significant differences in diet composition between size classes. Quantitative analysis showed that copepods make up about 79% of P. kauderni diet, and that other important components are decapods and isopods. There was an important variation in diet composition among the sites. Representative food items include ascidian larvae, chaetognaths, post-settled gastropod and bivalve juveniles, polychaetes, acarids, copepods, amphipods, stomatopods, cumaceans, isopods, euphausiids, ostracods, cirriped larvae, mysids, decapod larvae, tanaidaceans, and the larvae of teleost and chironomid insects (Vagelli and Erdmann 2002, Vagelli 2005).

Group Size:
Within its natural geographic range P. kauderni formed groups with a mean of 9.5 individuals, although the majority of them were composed of fewer individuals. Group size varied with age class, habitat and microhabitat. The mean size of the 448 censed groups (3,672 individuals) was 8.2 individuals, and the group means per site ranged from 3.9 to 19.8 individuals. Most groups (73% of all groups) were composed by few individuals (1 to 6). The largest single group found was about 500 individuals (Vagelli and Erdmann 2002, Vagelli 2005).

Breeding Biology:
Banggai Cardinalfish pairs defend territories jointly and for three likely reasons: 1) spawning site defense (viewed as unlikely because spawning sites do not seem to be limiting), 2) partner defense (females defending brooding males), and 3) to avoid spawning attempts by "sneaker male" (Kolm and Berglund 2004). Contrary to predictions for a sex role-reversed species, and all other apogonids studied to date, males assume the role of the principal aggressor towards intruders in their territories prior to brooding (Kolm and Berglund 2004). For both males and females, however, territorial aggression is greater towards intruders of the same sex. In experimental introductions of larger male intruders into territories held by male-female pairs, the intruding male was unable to replace the resident male even though the resident female may have courted the intruder; as well, males never courted intruding females. Because this species may have roles that are sexually equivalent, male and females likely play different roles in the defense of jointly-held territories (Kolm and Berglund 2004).

As with other cardinalfishes, the Banggai Cardinalfish is an obligate paternal mouthbrooder (Hayashi 1999). Reproductive behavior was filmed in situ by Dr. Masayoshi Hayashi (Yokusuka City Museum, Yokusuka, Kanagawa, Japan) and the film was broadcast on Japanese television in 1998. Other details on reproductive behavior were obtained from additional laboratory and field studies. Under laboratory conditions, P. kauderni reproduces throughout the year. Single females in captivity can reproduce once per month, whereas males mouth-brood up to six clutches per year. Females, under laboratory conditions can be reproductively active at about 9 months of age and 35 mm SL. The smallest female with signs of advance gonadal maturation found in the wild was 41 mm SL (Vagelli 1999, Vagelli and Volpedo 2004). Females initiate courtship and use a variety of different behavioral patterns during courtship interactions (Vagelli 1999, Kolm 2001). Between a few days and up to two weeks prior to courtship and spawning, a pair will separate from the main group of fishes, establish a spawning site, and commence territorial behavior (Vagelli 1999, Kolm and Berglund 2004). A secondary male may be allowed into the territory and be courted by the female although this male did not interfere with courtship of the primary male (Vagelli 1999). Spawning and juvenile release (settlement) in the wild appears to follow a lunar cycle, with a major spawning peak during full moon and a second, smaller peak during the last quarter, although in one geographically-distinct population major spawning activity occurs during the last quarter (Vagelli and Volpedo 2004). Courtship occurs during daylight hours and, in laboratory conditions, concludes by mid-afternoon. At the time of spawning and egg transfer, the female exudes an egg mass from her genital papilla that is pulled, fertilized, and then gulped by the male. P. kauderni possesses low fecundity, females produce small egg clutches of up to about 75 eggs of 2.5–3-mm in diameter. The mean clutch size found being incubated by males in the wild was 41 eggs (range=12 to 73) (Vagelli 1999, Vagelli and Volpedo 2004). The male broods an egg clutch for about 20 days; after hatching, the eleutheroembryos (free embryos) remain within the mouth cavity for another 10 days before release. Under laboratory conditions, a female would also court and even spawn with a secondary male (Vagelli 1999). Following spawning and egg transfer, females defend the brooding male from intruders while males manipulate egg masses within their oral cavities; occasionally, intruders attempt to take eggs from a male’s mouth. The fertility rate under laboratory conditions is about 40 to 60%. Besides normal loss due unfertilized eggs and embryos that do not finish developing, an important percentage of eggs are lost during the clutch transfer (Vagelli 1999). Males do not feed while incubating the eggs; upon hatching some 20 days after spawning, the embryos are held an additional 10 days until their yolk is consumed. Then, the juveniles, about 5.0 to 6.0 mm SL, are released from the male's oral cavity. A major settlement peak appears to occur during the full moon and a second minor peak during the new moon (Vagelli and Volpedo 2004). Vagelli (1999, 2004b) and Kolm (2001, 2002) provide laboratory studies of the reproductive biology and early ontogeny of this species, while Vagelli (2004a), Vagelli and Volpedo (2004) and Vagelli, 2005 provide data from field studies. Principal characteristics of the reproductive biology include: 1) parental care of an advanced degree, 2) an elevated level of energy investment per offspring, 3) low fecundity, 4) direct development, 5) a lengthy oral incubation period that includes the retention of free embryos after the eggs hatch, 6) settlement of juveniles within the habitat of their parents (Vagelli and Volpedo 2004).

The sex ratio within groups is approximately equivalent (Vagelli and Volpedo 2004). Longevity in captivity can reach 4 to 5 years (although reproductive activity decreases substantially after 2 to 3 years). However, in the wild most adult specimens are significantly younger (about 2 years old or less). Growth studies in captivity and using wild specimens show P. kauderni follows von Bertalanffy equation L∞ = 69 ± 1.58 mm, k = 0.21 ± 0.016, t₀ = -0.72 ± 0.15 months (r²= 0.99). At 12 months of age P. kauderni reaches a SL of about 43.5mm (TL of 64.5mm), at 18 months 47mm (70 mm TL). The largest wild specimen encountered was about 58 mm SL (88.5 mm TL) (A. Vagelli, pers. comm. on 27th Feb 2007).

Resilience:
This species has a relatively short life span (ca. 2.4 years), matures at an average of 0.8 years (FishBase 2004) and has a generation time of 1.5 years (A. Vagelli, pers. comm. on 27th Feb 2007); these are all indications of reasonably good resilience. Unfortunately, this species' small population size, limited distribution, low fecundity, great parental investment, and rate of extraction lower this species resilience with corresponding severe negative effects. The combination of a lack of planktonic dispersal and particular oceanographic characteristics of the Banggai region (deep channels and strong currents) has likely contributed to the extreme philopatry of this species. In addition, its within-parental habitat recruitment, sedentary nature, and shallow habitat preference preclude P. kauderni from dispersing even to nearby islands and have led it to a high degree of genetic structure (Bernardi and Vagelli 2004). P. kauderni is especially susceptible to indiscriminate collecting, e.g., its association with shallow microhabitats greatly facilitates its capture, while the lack of dispersal mechanisms make it almost impossible for this species to re-colonize areas where they have been depleted (A. Vagelli, pers. comm. on 27th Feb 2007).

This species is highly prized in the aquarium trade and thus highly vulnerable to over-fishing, post-capture mortality, and habitat destruction.

Threats to the Habitat:
Although resident in naturally-silty harbors and bays, this species might experience negative impacts from harbour dredging and associated pollution, as well as sediment from coastal development and use.

Juveniles may be vulnerable to local population dynamics of anemones and sea urchins that provide mutualistic microhabitat. Threats to these might be from harvest (aquarium trade or food trade) or coral bleaching (anemones). Adults may be vulnerable to local population dynamics of sea grasses.

Threats to the Species:

Exploitation
The Banggai Cardinalfish is highly-prized in the aquarium trade (Allen 2000, Vagelli and Erdmann 2002, Kolm and Berglund 2003). It has been heavily exploited by the aquarium trade since its rediscovery in 1994. Despite claims that captive breeding has been successful, most aquarium specimens are still captured in the wild. Fishes are collected, mainly with nets, and held in floating nets until purchased by fish buyers who visit individual fishers at least 3 to 4 times a month. Collectors are paid a small sum (ca. US $0.01 to 0.025 in 2001) per fish by buyers who, in turn, sell to exporters for US $ 0.10 to 0.12 a fish (Vagelli and Erdmann 2002). Since 1999, the fishery has expanded from Banggai Island and Bandang Island to villages in the Bokan area, on Bangkulu Island, Labobo Island, and Peleng Island, with most collection occurring near their own villages. By 2001, at least 17 villages and 230 fishermen were involved in the P. kauderni trade (Lunn and Moreau 2004). An estimated minimum of 600,000 to 700,000 individuals were collected per year by local fishers prior to 2001 (Vagelli and Erdmann 2002, Lunn and Moreau 2002); current harvest rates are believed to exceed 700,000 to 900,000 fish/yr (Vagelli 2005).

P. kauderni are shipped primarily by boat from the Banggai Archipelago to national exporters via Tumbak and Manado and to a Bali exporter via Palu, and also direct to Bali exporters. An estimated 115,000 fish/month were transported on the Tumbak–Manado route, 3,000/month along the Palu to Bali route, and up to 10,000 fish/month were sent direct to Bali in 2001 (Lunn and Moreau 2004). These numbers are close to earlier estimates of 50,000 to 60,000 fish/month arriving in North Sulawesi for exportation, with total estimated trade for 2000 and 2001 of 700,000 fish (Vagelli and Erdmann 2002). Transhipment mortality is high because of lengthy travel times, usually 18 to 48 hours by boat (Vagelli and Erdmann 2002); no data on mortality from collecting or holding prior to transhipment appears to be available. The high mortality rate contributes to the disparity in prices paid to fishers and buyers (Vagelli and Erdmann 2002). A minimum of four aquarium fish export companies operate in Bali; others exist in Kendary and Manado (Sulawesi). he majority of P. kauderni captured in the Banggai Archipelago are destined for the international aquarium trade, with most exported to the United States, Europe and Asia. Wabnitz et al. (2003) and Lunn and Moreau (2004) further document the aquarium trade.

In addition to the estimate of number of individuals collected and shipped reported in the assessment, trade surveys carried out by Lunn and Moreau (2004) suggest that a minimum of 118,000 Banggai Cardinalfish were sold each month by fishers in the Banggai Islands. Trade volumes are in all likelihood greater as this estimate only includes fish bought by Tumbak- and Palu-based buyers, not taking into consideration individuals collected and shipped from alternate locations, or lost to pre-sale mortalities in fishers’ holding cages (Lunn and Moreau 2004).

A recent study showed that, despite the use of non-destructive fishing methods, the fishery had a negative effect on fish density when sites with high fishing pressure were compared to sites with low fishing levels (Kolm and Berglund 2003). Fishing also had a significant effect on group size (halving of average group size where sites with high and low fishing pressure were compared), which may lead to strong negative impacts on individual fitness in the future (referred to as the Allee effect in the scientific literature) (Stephens et al. 1999, Stephens and Sutherland 1999, Kolm and Berglund 2003).

In addition to more detailed trade statistics to accurately reflect real trade volumes, regular monitoring of the fishery should be undertaken, particularly as studies seem to indicate that the expansion of the trade to new, previously unexploited areas is underway, moving outwards from Banggai Island to all of the major islands in the area. Lunn and Moreau (2003) also highlight that the pool of potential fishers could be large, particularly given that obstacles to entering the fishery appear to be minimal and alternative livelihood opportunities limited.

Other Threats:
This species is reportedly parasitised by four main parasite types. Three of them have been already identified, i.e., nematodes (6.6% of all individuals analyzed), digenetic trematodes (7.9%); and 4.8% of individuals were parasited by cestodes (plerocercoid larvae). The last type of parasites found consists of an undescribed isopod which was found encysted in the body cavity and on the external stomach wall of 7.2% of individuals analyzed. These endoparasites are currently being investigated and preliminary results indicate that they belong to a new family of epicaridean isopods with an unknown life cycle (Vagelli and Erdmann 2002, Vagelli 2005).

Indirect evidence strongly suggests that the Crocodile-fish Cymbacephalus beauforti (Platycephalidae), several species of Lion-fish Pterois (Scorpaenidae) and the grouper Epinephelus merra (Serranidae) prey upon P. kauderni, particularly in areas inhabited by large groups. Other likely predators are the Stonefish Synanceia horrida (Scorpaenidae), several species of moray eels of the genus Gymnothorax, and Echidna nebulosa (Muraenidae) and the sea-snake Laticauda colubrina (Elapidae) (Vagelli 2005).

The species is thought to suffer high mortality during the first days after settlement due to predation, including cannibalism (Vagelli 2002). For instance, despite that under laboratory conditions the average number of juveniles released was 40, and the average clutch size of brooding males in the wild was 18 embryos, out of 81 groups of new recruits found in the wild during 3 expeditions, most of them consisted of one or two individuals (mean: 2.3 individuals). The three largest groups found consisted of 15, 12, and nine individuals (Vagelli 2004a, Vagelli 2005).

A newly emerging threat (a viral disease) has been documented in wild-harvested individuals maintained in captivity. The origin of the iridovirus, as well as the prevalence in and impacts to wild populations, is currently under investigation (A. Vagelli, pers. comm. on 27th Feb 2007).

Frequent earthquakes recently affected several zones within the Banggai Archipelago had a potential detrimental impact on localized P. kauderni subpopulations

Soon after the Banggai Cardinalfish appeared in the aquarium trade, a breeding programme was developed at the New Jersey State Aquarium (Vagelli 1999). But apparently no concerted effort within the aquarium trade has been made to replace wild-caught fish with captive-bred fish (Vagelli 2002, 2004b). As this fish can be reared through its entire life cycle in captivity (Vagelli 1999), it is strongly recommended that efforts be developed to raise this species in captivity and in the field (it is highly recommended that such efforts be undertaken in partnerships with local communities, preferably in Indonesia, to avoid removing livelihoods from the area). Such initiatives would reduce the need to capture wild specimens to supply the trade and reduce impact on existing populations in the region.

In order to obtain reliable estimates of trade volumes for this and other marine ornamental species it is recommended that Indonesian government (and other governments) disaggregate the ‘aquarium fish’ category so that trade statistics can be obtained at least for marine versus freshwater species; and ideally by species.

It is further recommended that a trade monitoring system be established through direct collaboration with exporters. Targeting and inputting trade volumes of the Banggai Cardinalfish into GMAD could help spearhead such a monitoring initiative and allow better estimates of traded numbers to be derived (Wabnitz et al. 2003). Moreover, collectors and traders should be encouraged to gain MAC certification for the Banggai Cardinalfish.

Additional improvements in the sustainability of the current trade through directed training programmes on holding, packing and shipping, to reduce mortality rates of the species, are also recommended (Lunn and Moreau 2004). The development of environmental education material and programmes to promote public awareness are strongly encouraged and the potential implementation of marine protected areas should also be investigated (Lunn and Moreau 2004).

In summary, conservation actions required for this species include the development, implementation, and effective enforcement of regulations designed to significantly reduce and regulate the collection and export of this species for the aquarium trade (a proposal to include this species in CITES Appendix II was withdrawn (CoP 14 Prop. 19 ); and to protect and conserve critical habitat. Management actions that would benefit both this species and the fisher communities that harvest it at present could include artificial propagation at the local level with the intention of substituting completely captive-bred fish for wild-caught fish. In addition, a concerted and effective effort should be made to reduce post-capture mortality at all levels of the collection, marketing, and export chain.