Favorite Posts of 2017

Virginia Tech Ichthyology is devoted to teaching and learning about fishes.  We posted thirty nine blog posts in 2017.   Here I review the favorite blog posts from 2017.

Sea Lamprey and the Unexpected Costs of Shipping

Sea Lamprey accessed the upper Great Lakes when shipping access was improved.  They arrived at a time when Walleye, Lake Trout, Burbot, and Whitefishes were commercially over harvested.  The added mortality from Sea Lamprey was the tipping point that led to collapse of these valuable fisheries.  Expensive control efforts continue to the present time to deal with this invader.

Oral disc of the parasitic Sea Lamprey. Photo by Cory Genovese

Shades of Gray Snapper

Gray Snapper are common on Caribbean reefs that attract large spawning aggregations.  They go by a variety of names because they do not always appear to be "gray."  Gray Snapper are often overfished.  This story of the habitat and life history of Gray Snapper emphasizes the importance of conserving both inshore seagrass and mangrove habitats as well as offshore coral reefs.

Gray Snapper. Photo by Ned DeLoach  Source 

Puzzling over Large Aggregations of Sharks

This story explores how super abundant shark aggregations in a biosphere reserve persist because they rely on spawning aggregations of groupers for energy subsidies.  This discovery illustrates the futility of single species fisheries management.  Even if no sharks were harvested from this population, the population may decline depending on conditions for other fishes outside the biosphere reserve. Conservation of fish spawning aggregations, which are often targets of exploitation can help conserve shark populations, especially if combined with shark fishing bans.

Examples of shark foraging at night on the Camouflage Grouper Epinephelus polyphekadion (A, B, and C) and the Whitemargin Unicorn fish Naso annulatus (D).  Source

Pike Killifish: A Small, Specialized Ambush Predator

The Pike Killifish is an enigma. It is the only member of the Poeciliidae family that is a specialized piscivore.  Pike Killifish live in slow-moving streams and rivers, mangrove and weedy swamps, and inlets salty bays, where they associate with abundant submersed vegetation.  Their native distribution ranges from Costa Rico north into parts of Mexico.  From a single introduction in Miami-Dade County in 1957, the Pike Killifish became established in south Florida where their wide tolerance for temperature, salinity, and oxygen level allowed them to thrive in many habitats. 

Large adult Pike Killifish. Photo by Kenneth Tse Photography

Painful Stings of the Notorious Noturus

Madtoms are diminuitive catfishes that are bound to intrigue those who encounter them.  However, their pectoral and dorsal fin spines are sharp and deliver a painful venom.  Madtoms have a paradoxical combination of the strong anti predator adaptation while being a very popular bait fish.

How cute is this Margined Madtom Noturus insignis? Be careful, it packs a painful sting.  Photo by D.J. Orth.

Mad about Madtoms

These benthic nocturnal catfish arose in eastern North America sometime in the middle Miocene (that's 23.03 to 5.33 million years before the present).  Many of the twenty nine species have small, fragmented populations and are at-risk from a variety of human activities.  Although they are seldom the subject of thorough population studies, restoration activities are more commonplace today.   Madtom species are cryptic in more ways than one.   Click here to review some madtom photos.

Mountain Madtom Noturus eleutherus have a highly fragmented distribution.   photo by Tim Lane

Sharks without Fathers, by Rasha Aridi

In this essay, Rasha Aridi explains how shark offspring can be produced without a male contribution.   In 2002 a bonnethead shark gave birth in a zoo even though it had never been kept with a male.  This "virgin shark" mystery persisted and keen observers began to investigate cases of virgin birth in captivity.  Using DNA fingerprinting, these cases confirmed that all elements of the DNA in the offspring were from the mother.   Some species of sharks can produce offspring via sexual reproduction and parthenogenesis.

Parthenogenic zebra shark pup hatched and reared by the Burj Al Arab Aquarium Team. Source. 

Pelagic Thresher Sharks are Philippine Helpful, by Maddie Johnson

A major typhoon devasted an island resort leaving little or no infrastructure.  This essay examines the response of the locals in building a tourism-based economy based on the Thresher Shark.  Fisherman who used to make their money from catching as many thresher sharks as they could now make their money from this unique eco-tourism trade.

Thresher Shark.   Photo by Hugh Ross.  Source 

Siberian Taimen: Ensuring the Survival of the River Wolf, by Spencer Bell

Hucho taimen is known to the Chinese as the "river god's daughter." Mongolians protected their rivers for many centuries in keeping with their beliefs.  Consequently, some populations of the largest salmonid in the world still remain.  Today, recreational catch-and-release fishing has replaced poaching on the remaining Taimen populations.

Three Taimen, underwater photo from Eg River, northern Mongolia.  Source. 

Bow fishing for "Rough" Fish

Rough fish is an old term that once referred to less valued fish that had yet to be processed.  Today, more anglers are targeting rough fish for sport and bow fishing is among the fastest growing new fishing pursuits.  However, fishing regulations must change with the time and the term "rough" fish need to be replaced with more appropriate language.

Bow fishing at dusk.  Photo by Jason Emmel

Climate Change and the Fishes

Fear and doom stories about climate change have led to more research and development of strategies for adapting to eventual changes.  However, the scientific investigations have revealed a complex interactions of stressors related to climate change. Although there is still much to learn, it is apparent that we need to act now to protect cole and cool water refugia.

Documented responses of fishes in the southeastern USA to climate change. Green arrows indicate an increase or earlier seasonal response, and gray arrows indicate a decrease or later seasonal response  (Lynch et al. 2016).

Endemic Fishes of the New River

In my home watershed there are 8 species of endemic fishes.  They are all cool water specialists that found refuge in the upper New River during the last ice age.  These endemic fishes have limited distributions and will be disproportionately influenced by anthropogenic changes that may occur.  Read more about these 8 species in this post to learn why the New River is a special place for fishes.

New River near Rich Creek, Virginia.  Photo by Valerie F. Orth. 

Trends in Dam Removal: Reversing Irreversible Decisions

How many dams are there in the USA?  How many dams have been removed from streams? What happens to the stream after dam removal? What are the gaps in the science of dam removal?   Learn the answers to these and other questions.

Pigg River Power Dam before (photo by USFWS) and during demolition (photo by Roanoke Times)

Trends in Dam Removal: Reversing Irreversible Decisions, by Don Orth

The precautionary principle warns us not to make irreversible decisions. Yet building a dam proves to be an irreversible decision.  Someone else must deal with dam removal much later.    While dams provide services to our communities and economies, the average age of the 90,580 dams in the USA is 56 years.  Many billions of dollars are needed to repair aging and often high-hazard structures (Source).   

When I first began studying rivers in the 1970s, the idea of removing dams for purposes aside from safety would be heresy. Yet, more than 1,200 dams have been removed, especially in the Northeast, Midwest, and Pacific Northwest USA (Bellmore et al. 2017).  More than half of these were demolished in the past decade!   Understanding the effects of dam removal is limited due to the rarity of before-and-after studies of biophysical responses.  Therefore, the responses to dam removal cannot be easily generalized.  Surprisingly, in a few cases, a new river channel stabilizes relatively quickly and may even approach pre-dam morphology (see e.g., East et al. 2015).  If you wish to examine dam removals in your region, review the American Rivers dam removal database. 

 

U.S. distribution of (a) existing dams listed in the National Anthropogenic Barrier Dataset (n = 50,772); (b) removed dams from the Dam Removal Inventory Project (n = 874); (c) removed dams with before-after studies (n = 63). (Foley et al. 2017).

Dam removal science relies on the study of basic river geomorphology and ecology.  However, fewer than 10% of dam removals have been scientifically evaluated (Bellmore et al. 2017; Foley et al. 2017) and few studies examine important linkages between the physical and ecological consequences. Gordon Grant, Research Hydrologist with the US Forest Service, says “You can take a dam out all at once, or you can take it out slowly, and the consequences for the way sediment is released are profoundly different depending on how you do it.”  (Oliver and Grant 2017).  Major uncertainties exist as to the (1) degree and rate of reservoir sediment erosion, (2) excessive channel incision upstream of reservoirs, (3) downstream sediment aggradation, (4) elevated downstream turbidity, (5) drawdown impacts on local water infrastructure, (6) colonization of reservoir sediments by nonnative plants, and (7) expansion of invasive fish. These uncertainties hinder the full application of dam removal as a stream restoration strategy (Tullos et al. 2016).  Removals of the 64-m-high Glines Canyon Dam and the 32-m-high Elwha Dam were well-studied.  Here, investigators revealed that mainstem riffles were restored to cobble dominance after sediment was released and transported through the system (Peters et al. 2017).  

What’s happening in our local region? Unions and Simpkins Dam on the Patapsco River were removed in 2010 and removal of Bloede Dam, which is a complete barrier to upstream fish migration, is now underway (Harbold et al. 2015; Maryland DNR 2017).  These dam removals will provide an additional 65 miles of spawning habitat for blueback herring, alewife, American shad, hickory shad, and more than 183 miles for American eel in the Patapsco River watershed.

In Virginia, three dams were recently demolished after decades of planning and permitting.

Harvell dam was removed in 2014 from the Appomattox River, Virginia, permitting many migratory American Eel, American Shad, Alewife, Blueback Herring, and Hickory Shad to access spawning habitats over 100 miles upstream of the historic dam.   Watch the dam removal video.  

Monumental Mills Dam, built in 1816 on the Hazel River, was the 17^th dam removed in the Chesapeake Bay watershed of Virginia since 2004.  It is the most recent dam removal by the Department of Game and Inland Fisheries.  

The Pigg River power dam removal was in the works for 13 years before its removal in 2016.  This dam removal is outside the Chesapeake Bay watershed and benefits the Endangered Roanoke Logperch Percina rex as well as local paddlers. 

Roanoke Logperch.  Photo by Chris Crippen. 

The Roanoke Logperch exists in five isolated tributaries and the Pigg River population may now be able to expand with the removal of the dam.  The Roanoke Logperch does not occupy the slow, silty habitats that existed upstream from the dam. These fish feed on benthic insects that exist in clean, well-scoured habitats.   To find their prey, they often use their pointed snout to dislodge and turn over pebbles, thereby exposing their prey.   To witness this unique feeding behavior, watch this underwater video taken by Derek Wheaton.  

  

Pigg River Power Dam before (photo by USFWS) and during demolition (photo by Roanoke Times) 

Jordan’s Point Dam, an historic cotton mill dam on the Maury River near Lexington, Virginia, may be next on the removal list. Jordan’s Point Dam poses  a drowning hazard and is a barrier for fish passage. Jordan’s Point Dam is owned by the City of Lexington ,which is liable for lawsuits and must pay for repairs.  Maintenance and repair costs are more expensive than dam removal.  In June, 2017, City Council voted to remove the dam. 

Because dams change the landscape and waterscape in ways that may attract development, the removal of dams is often met with significant opposition.  This week the Millburnie Dam on the Neuse River, North Carolina, was removed.  Not all were in full agreement with the dam’s removal.   Dams create novel landscapes and waterscapes that in some cases is preferred by those growing up with the dam.  One planned Massachusett dam removal was halted as opposition grew.  One protester reflected that “You kill the dam, you are killing a part of me" (Fox et al. 2016). 

  

Migratory fish benefit from dam removals.  The American Shad and Blueback Herring now use over 28 additional miles of the Rappahannock River after the Embrey Dam was removed in 2004. Furthermore, Hickory Shad, Alewife, and Striped Bass have been documented above the Embrey Dam site, and American Eel increased in the upper watershed.  Bosher Dam on the James River, built in 1840, may still be a bottleneck for American Shad passage even though a fish passage was constructed. 

Dams removed from 1999 through 2016. Source: Caffin and Gosnell (2017). 

Dam removal trends are likely to continue as dams age and no longer serve original purposes.  Experience indicates that permitting requires work by numerous partners over a decade-long timeframe. The majority of US dam removals were privately owned, non-hydropower dams, which includes many investor-owned dams. Many of these were small and removal had minimal impacts, thereby allowing easier permitting under federal laws.  Other dams were authorized by legislative or executive actions, will prove more difficult to remove and removal will be subject to NEPA, ESA, and state water quality certification under the CWA.   

FERC relicensing is an opportunity to analyze choices as the FPA (Energy Policy Act of 2005, Public Law 109-58 § 241) recognizes that dams have a finite, useful lifespan and should be operated under the public interest (Chaffin and Gosnell 2017). Hydroelectric project owners should request an alternative licensing process (ALP) when substantial opposition to dam relicensing indicates a lengthy, mediated conflict resolution that may lead to decommissioning.  As public opposition to existing dams builds, it is important that we systematically study the effects of dam removal.  Each dam removal is a different large-scale experiment. We need to learn from each one in order to fill the gaps in our science (see below).   Restoring free-flowing rivers provides many new opportunities for connecting our youth with freshwater habitats.  

Gaps in the Science of Dam Removal (Bellmore et al. 2017)

·       Only 9% of dam removals have been described in published scientific literature.

·       No dam removal studies exist in the central U.S., and many states have few studies relative to the number of removed dams.

·       There are few studies of the smallest dam removals (those less than 2 m in height) relative to the prevalence of their removal.

·       Monitoring is generally short-term (1–2 years) and often includes little or no data prior to dam removal.

·       Fewer studies report biological and water-quality responses to dam removal relative to physical responses (e.g., sediment and flow).

·       Few holistic ecosystem-level studies exist that attempt to measure linkages among physical, water-quality, and biological responses.

Kids snorkeling in a river.  Photo: Jason Meador, Citizen Science Program Manager for Mainstream Conservation Trust. 

References

Bellmore, J.R., J.J. Duda, L.S. Craig, S.L. Green, C.E. Torgersen, M.J. Collins, and K. Vittum. 2017. Status and trends of dam removal in the United States. Wiley Interdisciplinary Reviews: Water 4:e1164.  doi: 10.1002/wat2.1164

Chaffin, B.C., and H. Gosnell.  2017. Beyond mandatory fishways: Federal hydropower relicensing as a window of opportunity for dam removal and adaptive governance of riverine landscapes in the United States.   Water Alternatives 10:819-839.     

East AE, Pess GR, Bountry JA, Magirl CS, Ritchie AC, Logan JB, et al. 2015. Large-scale dam removal on the Elwha River, Washington, USA: River channel and floodplain geomorphic change. Geomorphology 228:765–86. https://doi.org/10.1016/j.geomorph.2014.08.028

Foley, M.M. and ten coauthors. 2017. Landscape context and the biophysical response of rivers to dam removal in the United States.  PLOS ONE https://doi.org/10.1371/journal.pone.0180107  

Fox, C.A., F.J. Magilligan, and C.S. Sneddon. 2016. “You kill the dam, you are killing a part of me”: Dam removal and the environmental politics of river restoration.  Geoforum 70:93-104.  

Harbold, W., J. Kilian, and P. Graves.  2015.  Patpsco River dam removal study: Assessing changes in American Eel distribution and aquatic communities, 2013-2014.  Maryland Department of Natural Resources, Annapolis.   

Magilligan F, Graber B, Nislow K, Chipman J, Sneddon C, Fox C. River restoration by dam removal: Enhancing connectivity at watershed scales. Elementa 2016:4.

Oliver, M., and G. Grant. 2017. Liberated rivers: lessons from 40 years of dam removal. Science Findings 193. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.

Peters, R.J., M. Liermann, M.L. McHenry, P. Bakke, and G.R. Pess. 2017.  Changes in streambed composition in salmonid spawning habitat of the Elwha River during dam removal. Journal of the American Water Resources Association 53:871-885. DOI: 10.1111/1752-1688.12536

Tullos, D.D., M.J. Collins, J.R. Bellmore, J.A. Bountry, P.J. Connolly, P.B. Shafroth, and A.C. Wilcox. 2016. Synthesis of common management concerns associated with dam removal. Journal of the American Water Resources Association 52:1179-1206. DOI: 10.1111/1752-1688.12450