What Are Umbrella Fish? by Don Orth

“What's an umbrella fish?” a young student asked me.  Stumped, I replied “Never heard of one.”  The question bugged me until a library search confirmed there was no “umbrella fish.”  However, in conservation biology the term ‘umbrella’ species is one of several buzzwords used for surrogate species. Surrogate species may indicate biological diversity or environmental change or simply connect in the public’s imagination regarding habitat protection. Surrogate buzzwords include focal species, indicator species, keystone species, umbrella species, target species, foundation species, flagship species, and ecological engineer species (Caro 2010).   Even if the terms are loosely used, the species-centered conservation approaches can promote public awareness and raise funds for conservation. If it works, use it. 

Flagship species are primarily intended to promote public awareness and to raise funds for conservation. While flagship species are selected for their marketing value, umbrella species are selected based on ecological criteria and are expected to benefit a wide range of co-occurring species (Caro 2010; Kalinkat et al. 2017). Is it possible to select flagship umbrellas to describe species that explicitly integrate both functions?  Perhaps. The classic giant panda (Ailuropoda melanoleuca) is a popular charismatic species used since the 1960s by World Wildlife Fund for Nature for fundraising as well as it benefits for co-occurring endemic species.  

Recently, Kalinkat et al. (2017) identified over 60 potential freshwater flagship umbrella species.  So, there could be an umbrella fish. The next phase must be to implement and evaluate conservation strategies based on the flagship umbrella species approach.  Do the flagship umbrella species attract public attention and funding for conservation?  Is the diversity of co-occurring communities protected? We don’t know.

Emmanuel Frimpong (2018) argues that our lack of knowledge perpetuates ineffectual conservation practices in tropical Afrotropical freshwater fishes. We need to understand which fishes are rare and which are common and how the species may interact in aquatic ecosystems. His experiences, studying Nocomis breeding and nest associates, confirmed that seven species of cyprinids may breed on Nocomis nests. Therefore, Nocomis may be an umbrella species, but conservation action may take time.  His story emphasizes to us all that understanding the ecology and natural history of individual species is essential to adopting the language of flagship umbrella species.  That is one thing holding us back in fish conservation efforts. Frimpong (2018) then asks “Can we protect these rare species without protecting the common species that function as their hosts?”  Probably not!

A Bluehead Chub Nocomis leptocephalus guards his breeding mound in Toms Creek, Virginia.  Photo by Emmanuel Frimpong. 

We have yet to see if the flagship umbrella species approach develops and spurs effective conservation programs.  However, the concept of an umbrella is an important one. However, the multiple individual values and motivations around fish conservation should be embraced within a large, inclusive umbrella community of conservationists.  Here I review a few of these potential umbrella fish. Remember, while umbrella species may not exist for all systems, they may be effective in some.  Therefore, the concept is important to consider further to promote conservation action.

The Humphead Wrasse Cheilinus undulatus (also known as the Napoleon Wrasse) shares habitat with a diverse community in coral reefs. The species has a broad geographic distribution in the Indo-Pacific Ocean, a region with tremendous coral reef biodiversity. Like most wrasses (Labridae), the Humphead Wrasse is a protogynous hermaphrodite, meaning they will start life as females and may transition to males. As a large, conspicuous coral reef fish that is severely overfished, it fits the criteria for a flagfish species.  Most tropical marine protected areas (MPA) are too small to effectively protect the Humphead Wrasse and a significant scaling up of MPA is required (Weng et al 2015).  Protecting the Humphead Wrasse would protect many co-occurring species with shared habitat requirements.  Therefore, it may be both a flagship and an umbrella species.

Humphead Wrasse.  Photo by Paolo Macorig.  

Asian Arowana Scleropages formosus (Müller & Schlegel, 1844) is also known as the Golden Dragonfish or Golden Arowana. These fish are so highly valued by the aquarium trade that they are seldom eaten. Yet, the native swamps and sluggish rivers in southeast Asia are highly altered and the entire aquatic ecosystem and its services are at risk.  This recognizable and charismatic fish may be an appropriate flagship umbrella species.

Asian Arowana. Photo by Marcel Bulkhead. 

The largest salmonid in the world is the highly migratory Taimen or Huchen Hucho hucho.  The Taiman, known to locals as the “river god’s daughter,” may reach up to six feet and weigh up to 200 pounds.  Overfishing and habitat change reduced populations that once thrived throughout Mongolia and Siberia (Geist et al. 2009).   Since sport anglers value the large, unique fish, the Taimen is the target species in creating a large catch-and-release fishing reserve.  Read more here.

The Arapaima is one of the largest freshwater fishes and can reach 8 feet in length.  However, throughout it range in Brazil and Guyana it seldom reaches that large size anymore due to overfishing. One of the most heavily exploited fishes in South America, even today, scientists are not certain how many species of Arapaima exist (Stewart 2013a, 2013b; Watson et al. 2016).  While it fits some requirements for a flagship species, whether it’s an umbrella species will require more studies. 

Arapaima sp.  Photo by J-subculture.com 

The Mekong river and delta regions support a highly diverse ecosystem, which is heavily dammed.  Biodiversity of the Mekong basin is second only to the Amazon basin.  New fish species are described from the Mekong regularly and no other river has so many species of very large fishes. These include giant freshwater stingray Himantura polylepis, several giant barbs (Catlocarpio saimensis and Probarbus spp), and giant catfishes.  Two catfishes, the Mekong Giant Catfish (Pangasianodon gigas) and the Striped Catfish (Pangasianodon hypophthalmus) are candidate flagship umbrella species (So et al. 2006). Fish make up ½ to 2/3^rd of the diet of rural people of the Mekong and 2/3^rd of the people are engaged in wild capture fisheries so conservation of these areas is critically important.    

Mekong Giant Catfish (left) and  striped catfish Planet Catfish (right) 

Mahseer (Tor spp; Cypriniformes: Cyprinidae) are large-bodied, migratory freshwater fishes that are endemic to the monsoonal rivers of Asia. They are flagship species because of their economic, recreational and conservation interests.  Six of eighteen species of Tor are endangered, while others are threatened or data deficient (Pinder et al. 2015). Mahseers are referred to as “kings of aquatic systems” and are the primary targets of recreational anglers.  Fishing guides and recreational anglers have a stake in the protection of the catchments that support populations of Mahseer (Bower et al. 2017), yet the value of Mahseers as umbrella species has not been assessed.

Dekkan Masheer Tor khudree  Photo by J. F. Helias 

In North America, sturgeons (Acipenseridae), American Eel, Pacific salmonids, and Brook Trout are potential flagship umbrella species.   Brook trout Salvelinus fontinalis are well studied and a variety of conservation planning tools have been developed.  Many tools designed to characterize the continuum of viability, habitat condition, and vulnerability of Brook Trout populations may also protect a wide variety of co-occurring species.   

Sturgeons and Paddlefish in North America are possible flagship umbrella species.  In 2012, the North American Sturgeon and Paddlefish Society formed to focus on “current declines in sturgeon and paddlefish populations across North America, NASPS is dedicated to promoting the conservation and restoration of these species by developing and advancing research pertaining to their biology, management, and utilization.”   There are many threats that are specific to individual species of sturgeon. While study methods are improving, conservation efforts are playing a game of catch up. Perhaps a flagship umbrella species approach can help protect essential riverine habitats for hackelbacks.    

Although the status of American Eel is unclear, but one thing is clear.  American Eels may be hindered from reaching up to 84% of upstream habitats, thereby fragmenting the single, panmictic population.  Efforts to restore connectivity may benefit a large number of co-occurring fishes.

Four species of cyprinids that are nest associates with Bluehead Chub nests.  Photo by Derek Wheaton. 

We have a difficult challenge in conserving the fishes and their habitats.  Pluralism is the rule in conservation in general and fish conservation in particular. Many approaches, many values, and many types of people must be engaged in the process (Cooke et al. 2013).  Green et al. (2015) advocated for creating a much larger community that is strengthened, rather than factionalized, by pluralistic viewpoints.  Local and large-scale activities are important to our conservation efforts.  If the concept of flagship umbrella species can assist in making conservation more effective, then we should pursue the idea vigorously.

References

Bower, S.D., A.J. Danylchuk, R. Raghavan, S. C. Danylchuk, A.C. Pinder, A.M. Alter, and S. J. Cooke. 2017.  Involving recreational fisheries stakeholders in development of research and conservation priorities for mahseer (Tor spp.) of India through collaborative workshops.  Fisheries Research 186:665-671.

Caro, T. 2010. Conservation by proxy: Indicator, umbrella, keystone, flagship, and other surrogate species.  Island Press. 

Cooke, S. J. et al. 2013. Failure to engage the public in issues related to inland fishes and fisheries: strategies for building public and political will to promote meaningful conservation. Journal of Fish Biology 83(4):997-1018.
Frimpong, E. A. 2018. A case for conserving common species. PLOS Biology 16(2): e2004261

Geist J, Kolahsa M, Gum B, Kuehn R. 2009. The importance of genetic cluster recognition for the conservation of migratory fish species: the example of the endangered European huchen Hucho hucho (L.). Journal of Fish Biology 75(5):1063-1078.

Green, S. J., J. Armstrong, M. Bogan, E. Darling, S. Kross, C.M. Rochman, A. Smyth, and D. Verissimo.    2015.  Conservation needs diverse values, approaches, and practitioners.  Conservation Letters doi: 10.1111/conl.12204

Hogan, Z.S. 2011. Ecology and conservation of large-bodied freshwater catfish: a global perspective. American Fisheries Society Symposium 77:39–53.

Kalinkat, G. and seventeen coauthors. 2017. Flagship umbrella species needed for the conservation of overlooked aquatic biodiversity.  Conservation Biology 31:481-485.

Kalinkat, G. and seventeen coauthors. 2017. Flagship umbrella species needed for the conservation of overlooked aquatic biodiversity.  Conservation Biology Supplemental file.  18 pp.

Pinder AC, Raghavan R, Britton JR. 2015. Efficacy of angler catch data as a population and conservation monitoring tool for the flagship Mahseer fishes (Tor spp.) of Southern India. Aquatic Conservation: Marine and Freshwater Ecosystems 25(6):829-838. 204

So, N., J.K. Van Houdt, and F.A. Volckaert. 2006. Genetic diversity and population history of the migratory catfishes Pangasianodon hypophthalmus and Pangasius bocourti in the Cambodian Mekong River. Fisheries Science 72(3):469-476. 237

Stewart, D. J. 2013a. Re-description of Arapaima agassizii (Valenciennes), a rare fish from Brazil (Osteoglossomorpha: Osteoglossidae). Copeia 2013:38–51.

Stewart, D. J. 2013b. A new species of Arapaima (Osteoglossomorpha, Osteoglossidae) from the Solimões River, Amazonas State, Brazil. Copeia 2013:470–476.

Watson, L.C., D.J. Stewart, and A.M. Kretzer. 2016.  Genetic diversity and population structure of the threatened giant Arapaima in southwestern Guyana: Implications for their conservation. Copeia 104:864-872.

Weng, K.C., M.W. Pedersen, G.A. Del Raye, J. E. Caselle, and A. E Gray.  Umbrella species in  marine systems: using the endangered humphead wrasse to conserve coral reefs.  Endangered Species Research 27:251-263.

Plight of the Paddlefish, by Don Orth

If we were able to travel back in time to the Cretaceous period, the world would appear very different to us.  We would not recognize any of the first flowering plants that appeared in the early Cretaceous period.  We would not recognize our continental boundaries -- the supercontinent of Pangea was breaking apart.  A broad shallow sea covered central North America at the time.   We might recognize some of the dinosaurs, pterosaurs, and ichthyosaurs of the period, but only from museums or the Jurassic Park movie.   However, we would recognize the Paddlefish.   Paddlefish fossils appeared in Cretaceous and Paleocene formations and are clearly Paddlefish.  The American Paddlefish Polyodon spathula is as distinctive as its fossilized ancestors. It can reach 2.1 m (7 feet) and weigh as much as 74 kg (163 pounds).  Only one species of Paddlefish exists in North America.  The only other paddlefish in the world, the Chinese Paddlefish Psephurus gladius, is most likely extinct; no Chinese Paddlefish has been captured since 2003 (Dudgeon 2011).  Therefore, the plight of this unique large freshwater fish must be dealt with effectively. 

 Historical drawing of the Paddlefish from the U.S. National Museum.

Johann Julius Walbaum, a German physician and naturalist, described the Paddlefish in 1792.  Because of the cartilaginous skeleton, the paddlefish was first classified as a shark.  Walbaum named it Squalus spathula, thinking it was closely related to dogfish sharks.  Later the French naturalist Bernard Germain de Lacépède would name the genus, Polyodon.  Polyodon, is derived from the Greek root words meaning “many teeth.”  The basic body form is common to ancestral acipenseriform fishes since the Jurrasic.    The body is fusiform and tapers in the tail region to an asymmetric heterocercal tail.  The skeleton is mostly cartilaginous with minimal calicification.  Only small modified scales appear on the caudal fin base.

The Paddlefish has a very large mouth and a long, paddle-shaped snout that is one-third of its body length.   The paddle, or rostrum, is filled with electrosensory receptors that can detect the weak electrical fields generated by a swarm of zooplankton. The small eyes, numerous slender gill rakers (="many teeth"), and long tapering operculum flap are adaptations for a filter-feeding life in large, often turbid, rivers and oxbow lakes. The electrosensory pores on the rostrum help the Paddlefish orient to abundant zooplankton.  The numerous fine gill rakers help it feed efficiently on numerous small zooplankton, such as cladocerans and copepods. 

Paddlefish rostrum and close-up of electrosensory pores (Helfman et al. 2007)

The Paddlefish swim with its mouth open to filter feed on abundant zooplankton. Their first five years are all about growing to a large body size and they mature late and can live a long life, if not interrupted by fishing.  After five years, Paddlefish increase in body weight rapidly.   Many populations of Paddlefish have been studied to examine individual growth patterns and breeding patterns.  The dentary bone (i.e., lower jaw) can be sectioned to expose annual rings.  The oldest Paddlefish specimen was aged at 56 years old!  

 

Gill rakers of Paddlefish (left), photo by John Lyons.

Transverse sections of dentary bones (right). Photo from Adams (1942).

The Paddlefish is a migratory species that occurs in all large rivers of the Mississippi River as well as large Gulf Coast tributaries.   These are working rivers that have been highly modified for navigation and flood control.  The dams are barriers to migration and modify flow levels that serve as migration cues.  Navigable river channels have been dredged, deepened, and straightened, modifying habitats for Paddlefish.  Pollutants, contaminants, and waterway development continue to constrain populations of Paddlefishes.  The dcline in Paddlefish began in the early 1900s due to unregulated harvest.  Consequently, many states have research and management efforts to regulate harvest of populations. . 

Catch of Paddlefish from Illinois River, circa 1900 ( Forbes and Richardson 1920)

Paddlefish display strong spawning site fidelity and larges shoals of adults gather over clean gravel-cobble stream substrates for spawning.  Females delay spawning until they are between seven and ten years old and do not breed each year. Small eggs (2-3 mm) are produced by a single female and the total fecundity ranges from 9,000 to 26,000 per kg of female body weight.  That is why large female are so important to sustaining productivity of a population. A 20-kg female can produce 520,000 eggs and a 40-kg female produces over one million eggs.   However, these big old fecund female fish (BOFFF) are very rare in exploited populations.   

Fertilized eggs can hatch in 6-10 days while drifting downstream in the river currents; therefore, flow levels determine where larval Paddlefish will end up when they are ready to begin feeding.      Larval Paddlefish hatch at about 8-9 mm and have no paddle.  For a inside look at a Paddlefish larva, view this micro-CT scan.  The paddle begins to appear after larval metamorphosis and juveniles begin to resemble adult Paddlefish at 2 to 3 inches in length.   Recruitment of Paddlefish is usually better during years of high spring flows and recruitment failure is common during drought years.  

Larval Paddlefish SEM (Top)  Photo by William Bemis.  Underside and side views of juvenile Paddlefish, blue stained for cartilage.  Photo by M.C. Davis.

Management of Paddlefish populations is complicated because it requires coordination of efforts from many states that are responsible for this mobile species that does not stay in one state for its entire life cycle. Paddlefish freely move between political jurisdictions subject to differing management strategies and harvest regulations (Prachiel et al. 2012).   The Mississippi Interstate Cooperative Resource Association was organized in 1991 to improve interjurisdictional management.  Paddlefish is a major priority and increased knowledge is needed to manage this highly migratory and valuable planktivore.

  

When Paddlefish caviar sells for $24 per ounce (caviarlover.com), the demand for harvest will remain high even has catches are historical lows. Poaching remains difficult to stop and fraudulent sales of Paddlefish caviar as more expensive black caviar (Sturgeon) will no doubt continue.  Several different management strategies are in play.  One is stocking of juvenile Paddlefish since much is known about raising Paddlefish in captivity (Mims and Shelton 2015).   Some believe that Sturgeon and Paddlefish aquaculture will almost certainly be the major source of caviar in the future. For now, however, regulating harvest to protect females is needed throughout the range.  Some commercial fisheries have been banned to protect small fragmented populations.  Recently Hupfeld et al. (2016) advocated adoption of a basin-wide minimum length limit of at least 810 mm (or 32 inches) on Paddlefish fisheries in the Mississippi River.  Other proposals include a harvest slot and maximum size limits. Many dams serve to concentrate Paddlefish during the spring migration; here they are highly vulnerable to popular recreational snag fisheries.  The Oklahoma Department of Wildlife Conservation (ODWC) piloted a recreational harvest permit for Paddlefish in 2006.  Permit holders can bring their catch for the ODWC staff to clean and fillet.  In exchange for fillets the ODWC retains eggs from the female paddlefish for caviar.    This program has earned approximately $14 million since its inception, while processing 30,000 Paddlefish caught by anglers. 

Commercial harvest of Paddlefish (Pikitch et al. 2005).

McIntire et al. (2016) used “triple jeopardy” to describe the precarious situation faced by migratory fishes, such as the Paddlefish.  Paddlefish need suitable habitats in the feeding and breeding habitats, as well as along the migratory corridors connecting these habitats. Lack of spring high flows means that Paddlefish do not have a strong cue for spawning and recruitment is reduced (Prachiel et al. 2012).   Alterations of large rivers for navigation change the migratory corridors increasing the energy demands for upstream migration.  Construction of dams without fish passage restricts movement to historical breeding grounds.   Loss of oxbows means fewer productive feeding habitats exist.  In addition to the “triple jeopardy,” the Paddlefish now co-occur with large Asian Carp populations.What influence will this abundant non-native planktivore have on the planktivorous Paddlefish?  Without wise management actions, we risk keeping fisheries for Paddlefish trivial compared to their historic potential and we risk the loss of the last Paddlefish species on the planet.  

References

Dudgeon, D. 2011.  Asian river fishes in the Anthropocene: threats and conservation challenges in an era of rapid environmental change.  Journal of Fish Biology 79:1487-1524.

Firehammer, J. A., and D. L. Scarnecchia. 2007. The influence of discharge on duration, ascent distance, and fidelity of the spawning migration for Paddlefish of the Yellowstone- Sakakawea stock, Montana and North Dakota, USA. Environmental Biology of Fishes 78:23–36.

Forbes, S.A., and R. E. Richardson. 1920. The fishes of Illinois.  Illinois Natural History Survey Division.  357 pp.  

Hupfeld, R.N., Q. E. Phelps, S.J. Tripp, and D.P. Herzog. 2016.  Mississippi River basin paddlefish population dynamics: implications for the management of a highly migratory species.  Fisheries 41(10): in press.

McIntyre P.B., C. Reidy Liermann, E. Childress, E.J. Hamann, J.D. Hogan, S.R. Januchowski-Hartley, A.A. Koning, T.M. Neeson, D.L. Oele, and B.M. Pracheil. 2016. Conservation of migratory fishes in freshwater ecosystems. In Closs G, Krkosek M, & Olden JD: Conservation of Freshwater Fishes.

Mims, S.D., and W. L. Shelton.  2015.  Paddlefish aquaculture.  Wiley Blackwell,  Hoboken, New Jersey.  298 pp.

Neely, B.C., B.M. Pracheil, and S.T. Lynott. 2014. Hydrologic variables predict harvest in a recreational paddlefish fishery. Fisheries Management and Ecology 32: 259-263.

Paukert, C. and G. Scholten editors. 2009.  Paddlefish management, propagation, and conservation in the 21st century: building from 20 years of research and management. American Fisheries Society, Symposium 66, Bethesda, Maryland.

Pikitch, E.K. P. Koukakis, L. Lauck, P. Chakrabarty, and D.L. Erickson. 2005.  Status, trends and management of sturgeon and paddlefish fisheries.  Fish and Fisheries 6:233-265.

Pracheil, B.M., L.A. Powell, M.A. Pegg, and G.E. Mestl. 2012. Swimways: protecting paddlefish through movement-centered management. Fisheries 37: 449-457.