Friday, December 30, 2016

Fluvial Fishes Lab 2016

What mattered in 2016? Did we get published? Did it get read? Did it get cited? Did it make any difference? Can we make the next paper even better?   The research cycle continues as we celebrate the end of 2016.  

It never fails.  Whenever a submitted, revised, and revised and revised manuscript is finally acceptable for publication in a journal, I feel vindicated.  Sometimes I will spontaneously begin singing Queen's "We are the champions.  The process of research certainly feels like a "Hero's journey" to the authors.  There are no easy publications.  Each is a long struggle that ends in organizing a manuscript into the standard IMRAD template. This template has been used forever, but it  devalues the real process and excitement of discovery.   

In 2016, the Fluvial Fishes Lab completed papers and projects and we worked more on delivering and tailoring the message to other members of the public, hoping to make the science matter. All lab members are enthusiastic about explaining their work to members of the public.  Two noteworthy books I read this past year were Randy Olson's Houston, We Have a Narrative (Univ. Chicago Press, 2015) and Nancy Baron’s Escape from the Ivory Tower: A Guide to Making Your Science Matter  (Island Press, 2010).  Each provides many practical suggestions for making connections with the public.

In 2016,  Gary Grossman,   Jason Neuswanger, and I published  Innovative Approaches to Fisheries Education and Outreach in Fisheries.” It was an interesting collaboration, as we reflected on changes in college teaching over the past decades.   In 1995, I published an article in Fisheries entitled “Pogo Was Right, Let’s Change the Way We Teach Fisheries.”  Twenty years later we wrote,  "Despite the prescience of Orth’s (1995) article, many of the same problems remain in Fisheries education today."  This has to be the first time my name and “prescience” has been used in the same sentence.    If interested, you can read about the use of the use of music, ukulele, karaoke, ePortfolio, troutnut, and other contemporary approaches in education.  We remain hopeful that further pedagogical innovation will result in fisheries having a “signature pedagogy.”

In a paper on species distribution models (SDMs) of New River fishes, Jian Huang, Emmanual Frimpong and I examined the temporal transferability of these SDMs in terms of discrimination power and calibration with the temporarily independent datasets.   We used lasso-regularized logistic regression (LLR), boosted regression trees (BRT), MaxEnt, and ensemble models (ENS) to evaluate the habitat suitability of 16 fish species. 
Climate change is the most influential disturbance on fishes and these types of models will be more commonly employed to project future changes in species distributions.  However, biases, under-fitting, and overfitting were common issues to address in temporal transferability.  

Our analysis of catfish feeding before, during, and after the spring migration of Alosine fishes is in press in Marine and Coastal Fisheries.  The study depended on methods for identifying partially digested unidentifiable fish (PDUF) with DNA barcodes  The paper was the first to examine which species of Alosa occurred in guts of Flathead Catfish and Flathead Catfish. In this time frame, the Blue Catfish had broad, omnivorous diets, while Flathead Catfish fed solely on other fish. However, there were important spatial and temporal differences in diets.  Alosa species were consumed at higher frequency in the non-tidal, freshwater areas  than in oligohaline and mesohaline sites. Flathead Catfish are likely to have a greater per-fish impact on depleted Alosa species than the Blue Catfish. Further, dams and complex river structures appear to increase the vulnerability of alosines to predation by large catfishes.  We are now completely done with sampling catfish stomachs and busy with the analysis of data.    

Blue Catfish Ictalurus furcatus source
An opportunistic encounter with Clinch Dace during a spawning event eventually was accepted as a Note on spawning behavior  by Hunter Hatcher et al. (in press, The American Midland Naturalist) after many hours watching videos and interpreting behaviors, waiting for a brief release of gametes. 

Rock Bass recruitment in the New River has never been examined previously.  Pearce Cooper examined historic data sets and aged Rock Bass in the New River to examine major drivers of recruitment variation.   At two locations downstream from Claytor Lake Dam, high streamflow events after spawning reduced recruitment of Rock Bass at age-1.  The paper is available here

The relationship between average and maximum discharge (cm/s) in the previous year and the catch per unit effort (CPUE, # fish/h) of age-1 Rock Bass at the upstream and downstream sites during the months the relationship was found to be significant.
Michael Moore defended his Masters Thesis on the yeller finned minners in spring and began a PhD program at University of Missouri.  He'll move up from studying small, fragmented populations of a small minnow to studying small, fragmented populations of large sturgeon.  The final report to the Department of Game and Inland Fisheries,  Distribution and Population Characterizationof Clinch Dace (Chrosomus sp. cf. saylori) in the Upper Clinch River System, Virginia” provides a plan for conserving remaining populations.
Objectives of this project were to
(1) examine the historical changes in these watersheds to quantify features of historical Clinch dace streams; (2) confirm presence and relatedness of within-stream subpopulations separated by putative barriers; (3) identify and verify presence/absence of Clinch dace in the 125 km not previously sampled; (4) survey for spread in distribution of other Chrosomus in putative range of Clinch dace; (5) develop outreach plan landowners to protect extant populations. Clinch Dace occur at low densities in approximately 31.5 km of headwater streams. The mean estimate of global population size was 6,706 individuals. Most populations are likely influenced by low genetic diversity. Therefore, we examined 15 candidate conservation areas; ten of these areas have abandoned mine sites with $12.5M in unfunded restoration costs. The best candidate areas for conservation of Clinch Dace are: Pine Creek, Big Lick Creek, Mudlick Creek, and Hurricane Fork.
This is me after Bells Palsy paralyzed my facial nerves. Muscles on the right side of my face would not move.
In June I experienced sudden paralysis of the facial muscles on my right side. Paralysis of the facial nerve was caused by virus and inflammation and treated with antiviral and anti inflammatory medications.  The original prognosis that voluntary movement would gradually return in 3 to 6 months proved correct.  The facial nerve, or cranial nerve VII, is the nerve of facial expression. It is composed of approximately 10,000 neurons, 7,000 of which are myelinated and innervate the nerves of facial expression. That explains the slow regeneration time.

In September, I created and delivered my first Pecha Kucha presentation for Blacksburg Sustainability Week.  This concise format requires 20 slides of 20 seconds each, and makes it impossible to be spontaneous.   View it here.

Two new studies were funded in 2016.  One is a biological survey of the New River in the vicinity of the Fries Hydroelectic project; this is a collaboration with Verl Emrick and Caitlyn Carey, of the Conservation Management Institute
Google Earth photo of New River above Fries Dam. Note the mid-channel island built from the trapped river sediments.
The other new study, with Eric Hallerman, will examine genetic divergence in small populations of the Clinch Dace. This study will be led by Rebecca Bourquin, who left a position at Maryland Biological Stream Survey to begin her graduate studies last fall. 
The Virginia Tech Ichthyology blog had 54 posts for 2016.   The most viewed blogpost of the year was "Dammed If You Do:  Adopting Social Media in Teaching."   At the American Fisheries Society Annual Meeting in Kansas City, I was awarded the Excellence in Fisheries Education Award and named American Fisheries Society Fellow. 
Awarded the Excellence in Fisheries Education Award.  With Ron Essig and Jesse Trushenksi at the American Fisheries Society Meeting
Hunter Hatcher graduated in spring and sampled the New River near Fries Dam before beginning his Masters studies at Mississippi State University. 
Hunter Hatcher gets photographed at the Mudbass Classic 2016.
Hae Kim broke his own archery record with a record carp that was 45 lbs. and 7 oz.  It was taken in  Claytor Lake.
Hae Kim with his record carp.   Source.
Research on the non-native catfish is chronicled regularly in a blog, managed by PhD student, Joseph Schmitt.  You can read about our work at
Recognition at 2016 Service Dinner


Wednesday, December 21, 2016

Payara - What Big Teeth You've Got, by Don Orth

Many fish have teeth -- that is no surprise.  But one fish reminds me of the exchange between Little Red Riding Hood and the Big Bad Wolf.  Red Riding Hood says "Oh Granny, what big teeth you've got!" and the wolf replies "All the better to eat you with, my dear!"
The Payara, a fish from the Amazon, has amazing long and sharp fangs on the lower jaw.  These are also called vampire tetras or dogtooth characins and the fangs make them specialized predators.   The scientific name for one species is Hydrolycus scomberoides.  Hydrolycus’ is from the Greek 'hydro,' meaning ‘water’, and ‘lykos,’ meaning ‘wolf’. The species names ‘scomberoides’ is from the Greek skombros, meaning ‘tuna, mackerel’, and the suffix -oides, meaning ‘similar to.’   You can watch this video of this strange vampire fish in captivity and imagine what it might be like to encounter one in the wild. 
Upper jaw (ventral view) of the Payara (Toledo-Piza 2000)
These long fangs actually fit neatly into pockets in the skull; otherwise the fish could not close its mouth. Do people fish for them?  Yes.  Can you eat them?  Yes.  Can I keep them in your aquarium?  Yes, uh, well only the small ones.  There are several species and much more to learn about them.  Some species support subsistence fisheries, but the Payara has garnered international reputation among sport fishers.
Hydrolycus scomberoides (lower image) and Rhaphiodon vulpinus (upper image) Source
Consider the fishing possibilities.  Payaras can reach a length of 1.2 m (3.8 ft) and a weight of 18 kg (39 lb).   Watch  this video.    Imagine reeling it in, getting it close, and watching this head shake right before your eyes.
Head on view of the Payara.  Source
The Payara seem to be developing a strong following of adventurous anglers, including Zeb Hogan, Professor and National Geographic Explorer of Monster Fish fame.  He searched for them in Guyana.  "We found the Payara just below the Corona Falls on the Rewa River in Guyana," he said. "It's on the small side for megafish, at 40 pounds and 4 feet long.”    But the Payara has a monster gape and monster fangs to rival any other fish in the world. 

Large Payara Hydrolycus scomberoides caught by a recreational angler in the Orinoco River. Source
The Payara is a member of the family Cynodontidae (Order: Characiformes).  These dogtooth characins are very distinctive neotropical characiform fishes easily recognizable by the oblique mouth, well developed dentary canines, and relatively large expanded pectoral fins. The streamlined, muscular body is covered with small silver scales. They occur in parts of the Amazon and Orinoco basins and rivers that drain Atlantic slopes of the Guianas.  These fish have a long history with fossil specimens from Miocene deposits from western Columbia and Argentina. Three genera (Cynodon 3 species; Hydrolycus, 4 species; and Rhaphiodon, 1 species) comprise the family.  
Ichthyological explorations in the Amazon and Orinoco have observed these fishes in rivers, lakes and flooded forests.  They are mostly mid-water and surface-water dweller – specialized piscivores that use dentary canines to stab prey. The other characteristics, the large eye, laterally compressed body, and large oblique mouth suggests that they are visual hunters that can quickly move to capture live prey fish.    One study of dogtooth characins discovered that the numbers and biomass increased with water transparency, supporting the visual feeding specialization hypothesis. 
Hydrolyclus scomberoides was recently added to International Game Fish Association fly and rod classes.  Watch this video on fly fishing for the Payara in the Bolivian jungle.   Oliver White (2015) has promoted fly fishing for the Payara and claims that the little known area around Uraima Falls, Paragua River, is the best place in the world for large Payara.  This isn’t an easy fishing excursion, even for an experienced fly angler.  It is physically difficult to cast 12-weight with large flies and heavy lines, all the while perched on a rock amidst monster rapids.  
Illustration of the Payara by Duane Raver
Because of its trophic position, the Payara had some of the highest concentrations of methyl mercury among the fishes sampled in Bacajá River, Brazil (Souza-Araujo et al. (2016).  River conditions, lightly acidic pH, high temperature, and high concentrations of nutrients and dissolved minerals, all contribute to bacterial methylation in these waters.  Follow-up studies are needed in order to provide guidelines for fish intake and monitoring and managerial actions.

Other species include the Hydrolycus armatus Sabertooth Characin  and Hydrolycus tatauaia, ‘Cachorra’ or ‘Pirandirá  and Hydrolycus wallacei.    Some captive specimens have been observed in aquaria (see video). Rhaphiodon vulpinus, the Briara, is the only member of this genus.  Rhaphiodon is derived from the Greek rhaphis, meaning ‘needle’, and odous, meaning ‘tooth’.and vulpinus is from the Latin vulpinus, meaning ‘fox’.  The genus, Cynodon, includes other vampire fish (Cynodon gibbus, C. meionactis, and C. septenarius).    
Head detail of specimen of Raphiodon vulpinus, the Briara,  collected from the Paraná River, Argentina. © Claúdio Dias Timm
The Payara and its close relatives are among the thousands of little-studied fishes in South America. It is clear from work done to date that they are important predators, food fishes, and play an important role in these freshwater ecosystems.  However, there are 48 dams greater than 2 MW capacity in the Andean Amazon, and plans for an additional 151 such dams over the next 20 years (Finer and Jenkins 2012).  Given demand for harvest and modification of the river systems for hydroelectric power and development of watersheds for agriculture, these fishes deserve further attention and management. 

Zeb Hogan with specimen of the Payara
Finer, M. and C.N. Jenkins. 2012.  Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity. PLoS ONE, 7, e35126.
Melo, C.E., J.D. Lima, and E.F. Silva. 2009.  Relationships between water transparency and abundance of Cynodontidae species in the Bananal floodplain, Mato Grosso, Brazil.  Neotropical Ichthyology 7:215-256.
Reis, R.E., S. O. Kullander, and C.J. Ferraris.  2003.  Check list of the freshwater fishes of south and central America.  Pontifícia Universidade Católica do Rio Grande do Sul. Museu de Ciências e Tecnologia.
Souza-Araujo, J., T. Giarrizzo, M.O. Lima, and M.B.G. Souza.  2016.  Mercury and methyl mercury in fishes from the Bacajá River (Brazilian Amazon): evidence for bioaccumulation and biomagnification.  Journal of Fish Biology 89:249-263. doi:10.1111/jfb.13027
Toledo-Piza, M. 2000. The Neotropical Fish Subfamily Cynodontinae (Teleostei: Ostariophysi: Characiformes): A Phylogenetic Study and a Revision of Cynodon and Rhaphiodon. American Museum Novitates 3286: 1-88
Toledo-Piza, M., N. A. Menezes and G. M. dos Santos. 1999. Revision of the neotropical fish genus Hydrolycus (Ostariophysi: Cynodontinae) with the description of two new species. Ichthyological Exploration of Freshwaters 10(3): 255-280.
White, O.  2015.  Fangs on the fly: Hunting vampires in the Venezuala jungle.   Fly Fisherman Oct-Dec.  10-13.
Zacarkim, C.E., P.A. Piana, G. Baumgartner, and J.M. R. Aranha. 2015. The panorama of artisanal fisheries of the Araguaia River, Brazil. Fisheries Science 81(3): 409–416. DOI 10.1007/s12562-015-0853-z