Cardinal Sin: The Plight of the Banggai Cardinalfish Pterapogon kauderni KOUMANS 1933

Author: Kieron Dodds

Although the Banggai cardinalfish is beautiful and easy to keep, wild-caught specimens are no longer a responsible choice, as their collection endangers not only the fish, but perhaps also the aquarium hobby itself. This month TFH looks at the peril facing Pterapogon kauderni in the wild, and what aquarists can do to help save the species by refusing to buy wild-caught stock.

Cardinalfish in Danger

Unlike your typical species discussion, the purpose of this article is not to elaborate on the caretaking and breeding of the Banggai cardinalfish, but rather on the peril this fish faces, and how there is really only one thing we aquarists can do about it.

In 1994, Dr. Gerald Allen rediscovered this species, which was originally described in 1933. It was an immediate hit with marine aquarists worldwide—with Americans being the primary consumers—and the species has been collected and exported in massive numbers for the aquarium hobby trade since. Pterapogon kauderni is of no interest for any other trade purposes, and this is important for us to know for two reasons: First, we hobbyists are solely responsible for the harvest of this species. If their collection is causing the population to decline, then we are the only ones responsible. Second, this fish has merely been collected for slightly more than a decade. The massive decline in its numbers during that time should give pause to even the most skeptical among us.

Breaking Down the Economics

Harvest of this species is not an important part of any local economy, and its trade is only supplemental at all levels (SSN, 2007). There are only about 230 fishers (Lunn and Moreau, 2004)throughout this species’ range that collect the fish, representing approximately 0.2 percent (CITES, 2007)of the total human population in the area. At the current payment rate of 1 to 2.5 cents per fish (US$0.01 to 0.025) (Vagelli and Erdmann, 2002), its economic value, even in a depressed region, is barely significant. It is obvious how little this species’ collection helps support needy people. Let’s do the math.

With roughly 900,000 individuals being exported yearly (CITES, 2007) and a 55-percent mortality rate between collection and export (extrapolated by myself using monthly collections data versus export data, with the assumption being that the fishers do not have hundreds of thousands of individuals in personal tanks), it is not unreasonable to assume a total of 1.8 million fish collected. That amounts to 7826 fish per collector per year, which represents a supplemental income for each collector of between US$78 and US$195 per year. Who is affecting this species? We, the aquarium hobbyists, are. Who would be affected by a cessation of its collection? Only a handful of people—to the tune of about a hundred bucks a year each.

What Is Happening?

The Banggai cardinal is a very unusual marine fish, which is a major factor in the current precarious situation. It is a paternal mouthbrooder featuring low fecundity and an extended fry development period. Unlike many marine organisms that can feature thousands of pelagic planktonic larvae, it has virtually no dispersal mechanism. The handful of fry from each spawning settle in the domain of their parents, leaving little to no possibility for populating new areas or repopulating older, extirpated areas.

As a result, the Banggai cardinalfish exists in isolated pocket colonies throughout half the islands in the Banggai archipelago, as well as one location in northern Sulawesi, where it was probably introduced by commercial fishers. The species is also strictly home sited, which means that even if moved far away, the fish would return to their home site. Thus, small colonies exist in isolated pockets dispersed throughout their range.

This species also features very specific habitat preferences. Most groups are found in very shallow water from 1.5 to 2.5 meters (5 to 8 feet) deep. They also prefer living substrates, such as the long-spined urchin Diadema setosum. When threatened, the fish retreat into the spines of the urchins (or tentacles of anemones and branches of coral colonies). This means that collection methods are fairly simple, easy, and very effective.

In most cases, the entire urchin is scooped up, fish and all. Urchin populations in heavily fished areas are declining along with cardinals, so perhaps they are being consumed or otherwise destroyed. This also means there are many fewer urchins to be recolonized by straggler cardinals within the area, possibly leaving the remaining fish with no survival mechanism against predation.

No Controversy

Despite some dispute, it simply is not a questionable assertion that cardinalfish populations are declining precipitously. We know that all habitats are currently declining in population, and those declining most rapidly are also the ones most heavily fished. Unfortunately, we do not have population data preceding their initial collection in 1995, and there are always those who turn a blind eye and simply claim we don’t know what the original population was. This ignores the facts, however.

Current population densities average 0.07 fish per square meter (fish/m2), giving us a total wild population of approximately 2.4 million fish. However, in areas where it is known that fishing has not occurred, population densities are 0.63 fish/m2—almost 10 times greater! This extrapolates to an overall population of over 20 million fish only a decade ago. This is corroborated by known collection data. If you take the current population estimate of 2.4 million and add in the collection and export data of about 18 million fish collected since 1995, you come to just over 20 million fish again.

Facts About Population Decline

If this isn’t enough to convince you, consider these (non-extrapolated) data:

• In absolutely all areas where fishing is occurring, populations are declining, with the largest decline in those areas that are most heavily fished.

• In two areas placed under the protection of local authorities, populations increased during the collection bans, but have not recovered to the densities found in the one area we know has never been fished.

• In another area within its natural range—a privately owned pearl farm—there has never been any fishing allowed. Here cardinal population densities are 900 percent higher than the average populations everywhere else.

• Very recently, this pearl farm has seen a decline in Banggai cardinals as well, in conjunction with the start of known poaching. In the few months since poaching began, populations have already fallen to roughly three-quarters of the original density.

Unfortunate Politics

A year ago there was at least one stable population within the Banggai cardinalfish’s range. But now population decline is seen everywhere in the home range of the species. If the current rates of collection continue, it is estimated this species will suffer extinction—mostly because of collection for aquariums—within, at most, 10 years. Despite this evidence, the proposal for CITES II listing of this species was withdrawn by the United States during the Convention of the Parties (CoP14) in the summer of 2007 due to opposition of a political and economic nature, despite the fact that the home party, Indonesia, supported it. The proposal was written prior to the current IUCN Red Listing of Pterapogon kauderni as “endangered.”

There are industry organizations that oppose any regulation of trade in this species. Without supporting data to uphold their arguments, they also oppose CITES II listing of this species, citing the non-availability of seahorses within the trade as one of the examples of what might happen with Banggai cardinals. However, all ornamentally traded live rock and scleractinian corals are currently listed as at least CITES II, yet there seems no paucity of available specimens. A CITES II listing does not limit or eliminate trade, but rather leaves regulation up to local governments.

Many of the seahorse species that are no longer available were in very real danger at the time they were listed as CITES II. I believe that the dozen or so now readily available seahorse species should satisfy the hobby’s desire to possess seahorses at all levels. Many of the species that have disappeared from the trade were once in captive breeding programs. That these breeding programs have largely been unsuccessful actually illustrates why CITES II listing was necessary.

Massive Mortality

Through interviews with collectors and buyers (and surveys of their captures that correlate and corroborate each other), it is clear that the figure of 1.8 million fish collected per year is conservatively correct. Of these 1.8 million fish, approximately 55 percent die or are destroyed before they are exported, mostly out of Bali (this is an extrapolation of data from various sources). Unfortunately, we don’t know how many actually reach retailers, but the most recent GMAD (Global Marine Aquarium Database) data registers only slightly over 10,000 sold (Lunn and Moreau, 2004). If correct, this shows that mortalities during shipping from the exporter to the wholesaler/distributor are phenomenally large—99 percent! Though this is unrealistic, we might consider that even with an additional 50 percent mortality, roughly 500,000 fish are reaching the aquarium market each year. This is something to be seriously considered.

Most of the nearly one million fish being exported each year are coming into the United States. Where are all of those individual fish going? Are there half a million new marine tank keepers each year in the U.S. seeking out and purchasing every last fish coming in? Aquarists do report extremely high mortality rates in imported Banggai cardinals. This is in addition to the massive die-offs in transit.

The Bottom Line

Collectors are paid only a penny or two for the fish they collect, exporters from 10 to 700 times that. The going retail price for wild-caught Banggai cardinalfish is anywhere from $15 to $25, 750 to 2500 times what the collectors get. Those engaged in captive-breeding efforts must price their fish competitively in order to sell them. As a result, they get $25 to $30 for a captive-bred fish. Some have suggested that the solution is raising the retail price, but that will not decrease wild collection. If anything, collectors are likely to be paid more as the price trickles down, increasing collection of the species.

Because wild-collected individuals are so inexpensive and, for the moment, readily available, captive-breeding efforts are proving to be unprofitable or barely profitable, thus driving down the supply of individuals from these sources, or preventing these supply sources from increasing in number or expanding their programs. Currently, there are no known commercial-scale captive-breeding programs.

Warped Thinking

Rough estimates indicate wild populations of Banggai cardinalfish can double in one to three years (CITES, 2007). I have seen repeated assertions that this fish should be safe as long as less than half of the current estimated 2.4 million individuals are collected per year (personal communication), but this is nonsense. In order for a population in a given area to be able to double, there must be a given population left in that area. In fact, it is typical for entire colonies of Banggai cardinals to be fished out.

Two times zero is and always will be zero. Therefore, with sustained harvest, population doubling cannot occur in the case of this species, especially with the improbability of dispersed individuals from other colonies resettling an extirpated area. In fact, it appears that a much larger population is required to get that yearly doubling (see below about the Allee effect).

The introduced population in northern Sulawesi has grown. Apparently it is not currently being fished. The population started as a small colony of fewer than 100 individuals released in 2000; the current population is greater than 600 (CITES, 2007; Erdmann and Vagelli, in press), but you’d expect a population of 25,600 by now with yearly doubling! Of course, such introductions are never wise and usually damage or destroy local ecologies, so establishing colonies outside of the fish’s home range, even for collection and/or reintroduction, is not a viable option, but this case illustrates how slowly the population grows, even without harvesting.

Further Peril

In addition, a virus seems to be threatening this species (IUCN, 2007). The exact cause and course of infection is currently unknown. I think that there is a possibility that reintroduced individuals or individuals moved from other areas to repopulate extirpated areas are infecting local colonies. There is little genetic diversity within individual colonies. What this means is that, in a single population, it is likely that all individuals will be susceptible to the same infections, but that other populations may not be susceptible, or as susceptible, and thus could be carriers of pathogens that could wipe out entire susceptible colonies (CITES, 2007).

There is another peril to consider, the Allee effect, which is the positive correlation between population density and the likelihood of an individual animal to survive and/or reproduce. As population density declines, the survival and reproduction rate of individuals within that population declines.

It is unknown how many Banggai cardinals are needed for the individuals to be able to survive, find mates, and be stimulated to breed, but a significant Allee effect has been suggested by the data we have so far. This leaves only two possibilities: Either continued collecting will reach (if it hasn’t already) a critical density below which the species will be unable to recover, or reproduction and survival rates will continue to drop and not be able to keep up with harvest rates. Either way, continued collection bodes exceedingly poorly for the wild survival of this species.

Responsibility and Accountability

Since this species is solely collected for sale in the aquarium trade, each and every aquarist who has purchased one or more Banggai cardinals is responsible for the continued collection. Ultimately, should the species be driven to extinction in the wild, captive-bred populations are likely to continue to feed the aquarium trade. So, rest assured, those who read this and do no more than shrug, you will still, in all likelihood, be able to obtain Banggai cardinalfish. Prices may increase, and availability may decrease, but it is unlikely to disappear from the trade entirely. Unfortunately, celebrating such a view is incredibly short-sighted.

We all, by now, have probably heard about cyanide and dynamite fishing and other practices that are harmful to entire areas of the reef. Most of us agree that such practices are abominable. The aquarium industry, as a whole and in conjunction with ecological interests, has been greatly successful at eliminating these practices in many areas during recent years. But can we all sit back and relax, secure in the knowledge that Banggai cardinalfish are not collected in this manner because they are so easy to catch with simple nets and cages?

You might initially think so, but the aquarium trade has its enemies. In a recent paper, Kolm and Berglund use the Banggai cardinalfish situation to claim that no method of collection for the aquarium trade is nondestructive. Such an argument, of course, ignores that this species is a special case because of its unusual biology. For anyone who is unaware of the thousand or so other species in the aquarium trade that are not in peril, or for those with ulterior agendas, this article and others are certain to be cited out of context to justify the position that all wild collection of all species, no matter the method, should be banned. In our society’s current atmosphere, those willing to jump on “green” bandwagons without thought are increasing. We, as marine fish keepers, are a decided minority within our society, and should a movement to ban all collected imports gain even a little steam, we will be mostly powerless to stop it.

What Happens If Banggai Cardinalfish Go Extinct?

Rejoice, if you will, that captive-bred Banggai cardinalfish will still be available. And the other species currently being captive bred will, in all likelihood, remain available to the aquarist. But if you’d like to see a tang or a wrasse or any of the other thousand or so species not being captive bred, you may, in the near future, have to content yourself with images in books. If the Banggai cardinalfish becomes extinct in the wild, there is likely to be a backlash that severely harms the hobby.

It boils down to this: Is the possibility of being directly responsible for the extinction of a species, and the complete ban on all imports that might follow, worth having that one species in your tank right now? I would put forth that the most responsible thing to do at the moment would be to not purchase Banggai cardinalfish at all unless your dealer can verify that it is a captive-bred individual. That is, if you must acquire this species in the current climate. I, myself, will forego purchase altogether, feeling the most responsible thing is to just say “no.”

I would like to thank Eric Borneman for his time, aid, and continued efforts on this subject.


Banggai Cardinalfish Pterapogon kauderni CoP14 Prop. 19 (United States) Inclusion in Appendix II. Species Survival Network:

Erdmann, M., and A. Vagelli. 2002. “Banggai cardinalfish invade Lembeh Strait.” Coral Reefs 20:252–253.

IUCN. 2007. Taxon Datasheet for the Banggai Cardinalfish. Assessors: Dr. Terry Donaldson and Gerald Allen, in collaboration with RLA and Coral Reef Fishes Specialist Group members. Feb. 2007. 33 pp.

Kolm, N, and A. Berglund. 2003. “Wild Populations of a Reef Fish Suffer from the ‘Nondestructive’ Aquarium Trade Fishery.” Conserv. Biol. 17:910–914.

Lunn, K., and M. Moreau. 2004. “Unmonitored Trade in Marine Ornamental Fishes: The Case of Indonesia’s Banggai Cardinalfish (Pterapogon kauderni).” Coral Reefs. 23:344–351.

Marini, F. C., and A. A. Vagelli. “The Banggai cardinalfish: A 10 Year Update. The Aquarium Hobby’s New Poster Child for an Endangered Species.” C: The Journal 2:41–54.

Scott, M. 1996. “The Banggai cardinalfish: A Newly Available Species That May Become Too Popular for its own Good.” Aquar. Fish Mag. 8:86–87.

Tullock, J. 1999. “Banggai cardinalfish alert.” Aquarium Frontiers:

Vagelli, A. A. 2002. “Notes on the biology, geographic distribution, and conservation status of the Banggai cardinalfish Pterapogon kauderni Koumans 1933, with comments on captive breeding techniques.” Tropical Fish Hobbyist, November 2002.

Vagelli, A. A., and M. V. Erdmann. 2002. “First comprehensive ecological survey of the Banggai cardinalfish, Pterapogon kauderni.” Env. Biol. Fish. 63:1–8.

Additional Reading and Web Links

“Bangaii Cardinalfish Not to be Listed on CITES II.” Ornamental Fish International:

Convention on International Trade in Endangered Species of Wild Fauna and Flora: Additional Information on Biological and Trade Criteria in Support of an Appendix-II Listing for the Bangaii Cardinalfish, Pterapogon kauderni:

Convention on International Trade in Endangered Species of Wild Fauna and Flora: Consideration of Proposals for Amendment of Appendices I and II:

The IUCN Red List of Endangered Species:

“The proposal to list Bangaii cardinals into CITES II.” Marine Ornamental Fish & Invert Breeders Association:

See the full article on TFH Digital