Tuesday, December 29, 2015

Fluvial Fishes Laboratory Review of 2015, by Don Orth

Follow the wisdom of Calvin.
As New Year’s Eve approaches, I know it’s that time to consider New Year resolutions, but resolution making is no fun.   As soon as I write a resolution, I set myself up for failure!

Instead of making resolutions, here I review highlights of the research activities of the Fluvial Fishes Laboratory for 2015. 

It is a diverse collection of papers, including  a synthesis on the Smallmouth Bass, DNA barcoding of PDUF, first record of the pughead anomaly,  human dimension of trotlining, and the Clinch Dace in the coalfields of Virginia.

For the symposium on Black Bass Diversity, Brewer and Orth (2015) wrote a summary of the Smallmouth Bass.  The Smallmouth Bass has been widely introduced in North America and is the preferred target of millions of recreational anglers.  With future projections of climate change, the range of Smallmouth Bass will show expansions and contractions.   Competitive angling, catch and release, and emerging contaminants are prevailing challenges throughout much of its range.  A person could make a career of studying the Smallmouth Bass  -- I did!

Smallmouth Bass from New River.  Photo by Paul Bugas.
You can purchase the symposium from the American Fisheries Society  click here.  

In 2013, we started a pilot study to determine if we could identify what we had been labeling as partially digested unidentified fish (PDUF) in the diets of catfish.  Zach Moran did the first test series as an undergraduate research project and we have been using the protocol from Moran et al. (2015)  every since.    The DNA barcoding approach has allowed us to identify 27 species from PDUF, including small plain-looking minnows (Hybognathus regius) and migratory species of management concern  (Alosa sapidissima, Alosa pseudoharengus, and Alosa aestivalis).

Zach Moran, currently MS student at Arkansas Tech University.

Traditional morphological approaches to identification could never provide species level identifications once the key characteristics were digested.  The success of this investigation hinged on the prior efforts of Rob Aguilar of the Smithsonian Institution to collect and archive DNA sequences for fauna of the Chesapeake Bay.  

Since 2012, Jason Emmel and Joey Schmitt have been sampling Blue Catfish from James, Pamunkey, Mattaponi, and Rappahannock Rivers of Virginia in order to describe the spatiotemporal variation in diets.  
Jason Emmel (left) and Joey Schmitt (right) have sampled over 10,000 catfishes since 2012.

Among many unanticipated findings, we began to encounter pugheaded or bulldog specimens of Blue Catfish.    Pugheadedness  (which my autocorrect wants to call pigheadedness) is a deformation of the maxilla, premaxilla, or infraorbital bones that creates a pugheaded snout and a significant underbite.  All pugheaded specimens were captured within the tidal fresh zone (0–0.5 ppt) of the Rappahannock River; no pugheaded specimens were captured in oligohaline or mesohaline waters.  Prolonged summer hypoxia may be producing these deformities in the Rapphannock River, though more research is necessary to confirm this hypothesis.
Pugheaded specimen of the Blue Catfish
Trotlining for catfish is an old tradition, and was difficult to study because trotline fishers proved very difficult to track down.  Dickinson et al. (2015) indicate that trotline fishers fish often and harvest and eat large numbers of catfish (Channel Catfish and Flathead Catfish) from the New River.  This activity that was often driven by sustenance needs earlier in their lifetimes.  Trotlining is a declining activity at a time when other pursuits, such as kayak fishing, are increasing on the New River.  This hidden fishery and the participants are among the few river users aware of the occurrence of large catfish in the New River (photo).   
Ben Dickinson with Flathead Catfish captured with trotline on New River.
In “Isolating causal pathways between flow and fish in the regulated river hierarchy,” McManamay et al. (2015) examined how river regulation affects stream fishes through reach scale changes, not always through hydrology.    The type of dam and operation has a direct influence on sediment and temperature and was most important determinant of fish assemblage characteristics. This paper was only possible by leveraging collaborative sampling efforts conducted by the Tennessee Valley Authority. 
Ryan McManamay with buffalofish.
In a symposium paper, “Legacy of dams on the New River,” we described the localized effects of the dams of the New River drainage.  One of these dams, Fries Dam, is the oldest dam on the New River and is currently undergoing the FERC relicensing process.  
Map of New River near Fries.
Historic postcard photo of Fries and New River.
You may review photos describing the Fries Hydroelectric project by clicking here.   
Fries Hydroelectric project can produce 5,213 kW of energy with hydraulic capacity of 2,100 cfs.   Structures include a 41 foot high x 610 foot long rock masonry dam.  Water is diverted into a canal to the powerhouse; after flows exceed the 2,100 cfs capacity, flows are spilled over the 500 foot spillway crest.  Storage capacity is very limited due to sediment deposits above the dam.   I wrote a long, detailed letter to the FERC regarding the environmental consequences of continued operation of the Fries Hydroelectric project.
Google Earth photo of New River above Fries Dam. Note the mid-channel island built from the trapped river sediments.  Not present in the historic postcard photo.
Clinch Dace Chrosomus sp. cf. saylori.  Photo by Isaac Szabo

 This yet-to-be-named yellow-finned minnow maintains small, fragmented populations in this rugged landscape of the coalfields of Virginia.  In November of 2015, we flew over many of these sites with Southwings and gained a better understanding of the nature of the modifications of this landscape.   Runoff over the unweathered exposed rock elevates the ionic content of the stream water, usually far beyond the tolerance of macroinvertebrates and fish.   Here are a few photos from this flight.

So I resolve in 2016 to keep doing what I did last year.  Do research and move things along.  It seems to be working just fine. 


Brewer, S. K., and D. J. Orth.  2015.   Smallmouth bass Micropterus dolomieu, Lacepède, 1802.  Pages 9-26 in Tringali et al. Black Bass Diversity: Multidisciplinary Science for Conservation. Proceedings of the Symposium Black Bass Diversity: Multidisciplinary Science for Conservation, American Fisheries Society, Bethesda, Maryland.

Dickinson, B.D., D.J. Orth, and S.L. McMullin.  2015.  Characterizing the human dimensions of a hidden fishery: riverine trotline fishers.  Fisheries 40(8):386-394.

McManamay, R.A., B.K. Peoples, D.J. Orth, C.A. Dolloff, and D.C. Matthews.  2015.  
Isolating causal pathways between flow and fish in the regulated river hierarchy.  Canadian Journal of Fisheries and Aquatic Sciences 72(11):1731-1748.   DOI: 10.1139/cjfas-2015-0227

Moran, Z., D.J. Orth, J.D. Schmitt, E.M. Hallerman, and R. Aguilar.  2015.  Effectiveness of DNA barcoding for identifying piscine prey items in stomach contents of piscivorous catfishes.  Environmental Biology of Fishes  99:171-176.   DOI 10.1007/s10641-015-0448-7

Schmitt, J.D., and D. J. Orth.  2015. First record of pughead deformity in Blue Catfish.  Transactions of the American Fisheries Society 144:1111-1116.

Tuesday, December 22, 2015

Have Yourself a Merry Fishmas! Celebrate a Christmas Darter Too, by Don Orth

During this holiday season, there are many traditions that we follow without question.  They are like memorized lyrics “chestnuts roasting on an open fire."  We bake cookies, decorate a green tree, and leave cookies and milk out for the Christmas intruder/visitor.   However, there are also some holiday traditions that involve fish.  In the The Feast of the Seven Fishes, Italian-Americans celebrate the wait for the baby Jesus by eating seven types of seafood.  We eat pickled Herring at the stroke of midnight on New Year’s Eve to bring a year of good fortune.   Eating fish is thought to bring good luck, but in some cultures it is important to serve the fish with head and tail intact to ensure a good year from beginning to end. For religiously observant Jews, Gefilte fish has become a traditional food for Shabbat and Passover.  Gefilte fish resembles a large meatball made from ground fish and matzo ball mix and cooked in fish stock.   In one Czech Christmas custom, fish scales are placed under Christmas dinner plates to bring wealth to the house and carrying a fish scale in your wallet all year ensures that money will not run out.   

Scandinavian-Americans favor Lutefisk for their holiday traditionLutefisk, the food of poor Scandinavians, came to the United States with its immigrants and the tradition lives on in holiday Lutefisk dinners  Lutefisk is a well-disguised Atlantic cod. It is not surprising that cod was a common food of Scandinavia, eaten for centuries; the northeast Atlantic has the world's largest population of cod. The traditional preserving method first air dries the cod in a cool, dry climate until it appears as hard and dark as an old shoe. This extends the shelf life by several years. Later it is reconstituted by soaking it in lye.  Yes, lye. To make the fish edible again, the lye-reconstituted fish is soaked repeatedly in cold water.  This tradition lives on despite the fact that most dislike the taste and texture of Lutefisk.   But it is a tradition, just like Lou T. Fisk, the fishy ambassador for Madison, Minnesota, the self-proclaimed Lutefisk capital of the USA.  

Given the many holiday traditions involving fish, it is surprising to me that there are so few fish named for the Christmas holiday.  The International Commission on Zoological Nomenclature is the adviser and arbiter of scientific names of animals.  However, common names are not standardized by this international code.  Why are so few fish named for Christmas?  There is a Christmas Wrasse from the western Pacific Ocean, and a Christmas Darter Etheostoma hopkinsi and a Holiday Darter Etheostoma brevirostrum from the Southeast USA  If you know of other fish named for Christmas, please post a comment below. 
Two Christmas Darters. Top by Dustin Smith and Bottom by Michael Wolfe
The Christmas Darter is one of the 184 small, colorful bottom dwellers in the Family Percidae.  They are small, tube-shaped fish with stiff spines on the first dorsal fin.   The Christmas Darter was named for its bright red and green breeding coloration.  Its scientific name hopkinsi was for Milton N. Hopkins, Jr., who collected the type specimen.    The Christmas Darter has a small conical shaped head, broad frenum (frenum is fleshy bridge that connects the snout and the upper jaw), and 2 anal spines.  Breeding males have a bright red submarginal band on its spiny dorsal fin.  What makes it the perfect Christmas specimen are the 10-12 dark green bars on side, separated by red in the male.  The female has yellow blotches between the green bars.   The Christmas Darter is restricted to the Savannah, Altamaha, and Ogeechee River drainages in South Carolina and Georgia     These small fish are only 1.5-2.5 inches as adults and inhabit gravel-bottom riffles of creeks and small rivers (Rohde et al. 2009 p 358-360).
Distribution of the Christmas Darter.  Fishes of Georgia website.
So consider starting a new tradition this Christmas.  Print out this sketch of the Christmas Darter and color it in with bright red and green and add it to your Christmas decorations.  Or download an app to digitally "paint" the Christmas Darter.   Perhaps decorate a few Christmas Darter cookies or shape some Gefilte fish to resemble Christmas Darters.

Christmas Darter.  From SC DNR Fishes of Concern Coloring Book   
Espinsosa-Pérez, H., L.T. Findley, C.R. Gilbert, R.N. Lea, N.E. Mandrak, R. L. Mayden, J.S. Nelson, and L.M. Page. 2013.  Common and Scientific Names of Fishes from the United States, Canada, and Mexico, 7th edition.  American Fisheries Society, Bethesda, Maryland. 
Knepley, M. 2014.  Fish in Focus:   Christmas Darter, Etheostoma hopkinsi  American Currents  Winter issue.

Rohde, F.C., R.G. Arndt, J.W. Foltz, and J.M. Quattro.  2009.  Freshwater fishes of South Carolina.  University of South Carolina Press, Columbia, South Carolina. 430 pp.
South Carolina Department of Natural Resources.  N.d.  SC Fishes of Concern Coloring book.    
Straight, C.A., B. Albanese, and B.J. Freeman. [Internet]. [updated 2009 March 25]. Fishes of Georgia Website, Georgia Museum of Natural History; [cited December 21, 2015]. Available from: http://fishesofgeorgia.uga.edu

Friday, December 18, 2015

Atlantic Needlefish by Don Orth

Who am I?  I have a really long body with my upper and lower jaws studded with numerous sharp teeth.  I specialize in appearing invisible near the water surface.  I often leap and skitter across the water surface at high speeds when alarmed.  I impale humans even though I am not a swordfish or billfish.  I can attack fish prey by diving down from the air.  I have a single, not paired, gonad. I have green bones.   Who am I?    If you guessed “needlefish,” then you are correct!

Atlantic Needlefish Strongylura marina (Walbaum) Photo by Michael Clark © TNFISH.org
Needlefishes comprise a New World clade of fishes distributed along the Pacific and Atlantic coasts of the Americas and in freshwater basins of Central and South America. Of the ten genera, three are endemic to South American rivers.  The clade is most closely related to the flyingfishes (Excocoetidae) and Halfbeaks (Hemiramphidae).    Our most common North American species is the Atlantic Needlefish Strongylura marina (Walbaum).  Strongylura is from Greek strongylos, meaning round and oura meaning tail, which refers to the round cross section shape.  The species name marina is from the Latin marinus, meaning “of the sea.” Atlantic Needlefish is long, slender, and typically a silvery color with a dark blue stripe along the side of its body.  They grow to about 2 feet and the upper and lower jaws extend into long beaks filled with sharp teeth.  They are native to the western Atlantic from Massachusetts to Brazil, including coasts of the Gulf of Mexico and the western Caribbean Sea.  Atlantic Needlefish are most commonly found in estuarine and shallow coastal habitats but can sometimes move to freshwater areas such as coastal ponds or rivers.  Spawning occurs in freshwaters where the adults often migrate in search of juvenile fish prey.

The Atlantic Needlefish is a frequent invader of rivers up the Fall Line.  It maintains freshwater populations in some river systems.  It is physiologically well adapted to salinity fluctuations.  In fact, after the construction of the Tennessee-Tombigbee Waterway in 1985, the Atlantic Needlefish gained access to the Tennessee River drainage in Alabama and Tennessee where it maintains freshwater populations.

The long nose and hundreds of tiny, sharp teeth of the adults mean that this is a serious predator on other fishes.   Needlefish swim near the surface and feed on small fishes by charging the prey and clamping it between its jaws.  The jaws are then manipulated to orient the fish head first so it may be easily swallowed.   The juveniles have longer lower jaws than upper jaws and feed on amphipods, shrimp, and mysids.    The jaw morphology is reflective of the diet.    

Just look at those teeth!  Photo by James Green
Atlantic Needlefish are fast swimmers and have a unique form of locomotion, referred to as anguilliform.  Anguilliform refers to the large undulations of a long body that are also seen in eels.  However, other anguilliform fish tend to move through complex habitats, not open or near surface waters.   The needlefish is different in that the origin of the pectoral fin base is high on the body and the bases of their relatively large pectoral fins are oriented closer to vertical than to horizontal.  Pectoral fins of the needlefishes serve as stabilizers during fast swimming.
Anguilliform swimming of Atlantic Needlefish at 1 L/sec Photo: Liao 2002.
Adult needlefish also have another way to stalk and attack schools of prey fishes.   The adult needlefish actually leaps out of the water and makes an aerial attack on unsuspecting prey fish.  This strategy greatly increases their attack range.   And with their toothy gape, the success rate is very high.
Aerial attach in needlefish.  Day et al.  2015
Atlantic Needlefish is not immune to predators. Large fish and fish-eating birds, such as the Osprey and the Black Skimmer, prey heavily on Atlantic Needlefish.  One manner of hunting and escaping from larger predators is to leap and skip across the surface of the water when alarmed.  Its defense against predation involves rapid lunging at predators, sometimes penetrating them with the needle-like nose. Since the Atlantic Needlefish is so common it often the basis for designing lures and flies for sportfishing.
Needlefish lure from striperspace.com (left) and needlefish fly from discountflies.com (right)
The shallow, coastal waters attract numerous aerial and aquatic predators.  Fast swimming, jumping, and skittering across the surface are all effective anti-predator strategies.  Yet, the needlefish has one other adaptation to reduce predation.   Predators cannot strike if they cannot see their prey.  The needlefish specializes in appearing invisible in the clear, well-lit surface waters.   Other fishes can do this as well.  These “invisible” fish have platelets in their scales that reflect polarized light (i.e, light moving in a single plane) in such a way as to blend in.  Recently, investigators used a camera system that showed that these invisibility-specialist fishes hid well in polarized light.  Since polarized light is common underwater, the invisibility specialization is used by many fishes.  The needlefish is just one of many fish that take advantage of this.

Atlantic Needlefish blends in with its surroundings in this coral reef habitat.  Photo: D.J. Orth
Atlantic Needlefish represent a great example of the phenomenon called “heterochrony.”  Heterochrony is defined as developmental change in the timing or rate of events, leading to changes in size and shape.  In the Atlantic Needlefish, the jaw changes with maturity, as upper jaw grows more slowly than the lower jaw.   At hatching (~9-14 mm), larvae are “halfbeak” in appearance and both jaws are short and of equal length.  Small juveniles (35-50 mm) continue to resemble a halfbeak, where the upper jaw is much shorter than the lower jaw.   At full maturity, both jaws are approximately equal in length.    The jaw morphology reflects a diet of plankton during the “halfbeak” stage and a fish diet during the adult stage.
Atlantic Needlefish at halfbeak stage and needlefish stage (Boughton et al. 1991)

How did this heterochrony ever happen?   The ancestral member of this group was presumably similar to the halfbeak.  Then genetic mutation to permit equal growth of upper and lower jaws.
Hypothesized evolutionary tranistion from the halfbeak-type ancester to the needlefish (Lovejoy and Collette 2001)
Needlefish are fun to catch on light tackle (see video and video).  Since they are active feeders you can catch them with small fish or shrimp as bait.   Needlefish are attracted to light so you can also draw them in with a flashlight if fishing at night.   A hard strike is needed to hook the needlefish.  Expect it to jump in the air while you reel it in.  Be careful to keep your fingers away from those sharp teeth!  The International Game Fish Association’s hook-and-line record is 1.47 kg (=3 ¼ pounds).    Many anglers practice catch and release, but needlefish are edible. You are in for a big surprise when you clean a needlefish.  The bones appear green due to a heme degradation product, biliverdin, which has an affinity for the structural protein associated with the bone. Also, when you examine the entrails you will not find paired gonads that are characteristic of fish.  The needlefish has only one gonad, an adaptation seen in other long-bodied animals.
The bones of needlefish are green!  Photo by MiniSteve.com
One of the unfortunate human interactions with needlefish occurs due to their behavior of jumping and skittering across the water surface.  Human injuries are thought to be accidental when the needlefish is startled; although some reports sensationalize the encounter and report that “needlefish attack at 60 km per hr.”  Needlefish are attracted to bright lights and injuries are often reported among night fishermen who get between lights and lunging needlefish.  Injuries have also been reported in swimmers, canoe, divers, riders, surfers, and windsurfers.  In fact Richard Clinchy’s Dive First Responder (1996) includes a section on Needlefish Punctures.   Windsurfing creates a greater risk to speed of needlefish and windsurfers, which may achieve a relative velocity of perhaps 100 km/h or more.  Although injuries are rare, they can be life threatening depending on the organ injured.    Risk of impalement by a fish is greater for needlefish than for those truly weaponized fish, such as the swordfish and marlin.  
Radiograph of lower limb impaled by needfish.  photo by Link et al. 1999.
My advice is “Save the Needlefish” and avoid windsurfing. The needlefish dies and the windsurfer ends up in the local emergency room.  Also, avoid using gill nets in areas with schools of needlefish.   Needlefish have to be among the top fish you don’t wish to encounter in a gill net. 
Needlefish entanged in a gill net.
Boughton, D. A., B. B. Collette, and A. R. McCune. 1991. Heterochrony in jaw morphology of needlefishes (Teleostei: Belonidae). Systematic Biology40(3), 329
Brady, P.C., and sixteen coauthors.  2015.  Open-ocean fish reveal an omnidirectional solution to camouflage in polarized environments.  Science 350(6263):965-969.  DOI: 10.1126/science.aad5284      
Clark, J.J., H. C. Ho. 2012.  Two cases of penetrating abdominal injury from needlefish impalement.  Journal of Emergency Medicine 43(3):428-430. doi:10.1016/j.jemermed.2009.10.013
Day, R.D., F. Mueller, L. Carseldine, N. Meyers-Cherry, and I.R.Tibbetts.  2015.  Ballistic Beloniformes attacking through Snell’s window.  Journal of Fish Biology   DOI: 10.1111/jfb.12799
Jüttner, F., M. Stiesch, and W. Ternes. 2013.  Biliverdin: the blue-green pigment in the bones of the garfish (Belonebelone) and eelpout (Zoarcesviviparus).  European Food Research and Technology 236:943-953. 
Liao, J.C. 2002.  Swimming in needlefish (Belonidae): anguilliform locomotion with fins.  The Journal of Experimental Biology 205:2875-2884.  
Link KW, Counselman FL, Steele J, et al. 1999. A new hazard for windsurfers: needlefish impalement. Journal of Emergency Medicine 17:255–9.
Lovejoy, N.R., and B.B. Collette. 2001.  Phylogenetic relationships of New World Needlefishes (Teleostei: Belonidae) and the biogeography of transitions between marine and freshwater habitats.  Copeia 2001:324-338.
Rouvillain, J.L., A. Donica, C. Gane, C. Zekhnini, E. Garron, and A.P. Uzel.  2013.  Windsurfing hazard caused by needlefish.  European Journal of Orthopaedic Surgery & Traumatology  23(2):293-295.