Wednesday, December 11, 2019

Fluvial Fishes Lab Year in Review, by Don Orth

Before the calendar changes, let's look back on 2019.  Long ago I adopted Author D.S. Mixell's  New Year's resolution: “ never make New Year's resolutions. Hell, it's been the only resolution I've ever kept!”   I am required to create an electronic Faculty Activity Report (eFAR), not to make resolutions. Most colleges and universities have an electronic data base designed to make reporting as tedious and uninteresting as possible.  While it serves for annual merit review purposes, it's format and requirements are annual reminders of the creeping and creepy corporatization of the university. 
"The corporate university's language of new findings, technology transfer, knowledge economy, grant generation, frontier research, efficiency, and accountability dominates how academic scholarship is now framed both within the institution and outside it." Berg and Seeber (2017)
Calvin, from Calvin and  Hobbes, has plenty to say about resolutions.  Watterson (1988).
Two years ago while working on my eFAR, I took a break to visit Virginia Tech's Animal Hospital carrying a dead Freshwater Drum Aplodinotus grunniens. It was destined for the x-ray machine. My Ichthyology students had an easy time finding the lucky stones with the help of this radiograph (below), showing the large ear bone behind the eye socket and under the brain case. Large otoliths in the Freshwater Drum are called lucky stones, which are often found washed up on the river banks or lakeshores.  I have no lucky stones in my pocket, but do keep a lucky fish scale in my wallet.
Lateral view of Freshwater Drum radiograph. 
The Virginia, Virginia Tech, and West Virginia chapters of the American Fisheries Society met in Blacksburg for a joint annual meeting.  The first-day workshop focused on R3 Initiatives to Recruit, Reactivate, and Retain anglers.  John Arway, retired Executive Director of the Pennsylvania Fish and Boat Commission, was our keynote speaker. John shared his experiences and questioned whether the North American model of conservation is still relevant for the 21st century (hint: it's not).  Ever since this session, I've had the word "relevance" buzzing around in my head.  Can I find messages of relevancy for my eFARS?  Jane Lubchenco, Tyler Laureate and former NOAA administrator and distinguished University professor,  wrote that:  “Scientists need to make their research more relevant, more understandable, more connected to people's lives. I believe this is part of the way to address our ‘post truth’ world.”  Science and society are linked and making work relevant is not as easy as it sounds. Many debate how scientific findings should be shared and by whom.  
John Arway presents keynote address to AFS chapters meeting in Blacksburg, Virginia.
Hae Kim, BS 2017, won the coveted fertility fish hat at the annual chapter raffle. 
I hope my teaching and scholarship is relevant beyond the classroom.  Virginia Tech Ichthyology is a public Facebook group that has topped 1,020 group members this year.  Members greatly enrich novice student experiences in Ichthyology.  Students are reminded daily of how others are making a living and finding enrichment through fishes.  Students posted relevant assignments to Facebook, including the Ichthyologist of the WeekVirginia Tech Ichthyology class blog is viewed by people around the world each day and provides an outlet for relevant student writings.  Please share these outlets with others who may find them relevant.   
Ichthyology class, spring 2019, with Mahi Mahi Coryphaena hippurus.
Andrew Bartee (left) and Emma Hultin (right) are excited about capturing a colorful Luxilus!
Hanna Moreland (right) and Emma Hultin (left) examine live fish in a photo box.  We can never have enough field trips to learn more about the fishes.
Ichthyology class at the wet and sweaty end-of-semester field trip. 
Relevance in Virginia Tech’s strategic plan means commitment to a comprehensive global land grant mission and transdisciplinary learning and engagement.  Every day we connect with students in ways that transcend the classroom experience. It's called the Virginia Tech Difference, which relies on a globally relevant campus experience that has a life-long influence on students. At the annual meeting of the American Fisheries Society in Reno, Nevada, I was honored to receive the 2019 Excellence in Public Outreach Award.  Relevance depends on writing for many audiences, and not just for the few scientists in my own narrow field of interest. Even introverts can do public outreach and I hope my students will be inspired to explore innovative methods to reach a broader audience.

Executive Director of AFS, Doug Austen, congratulates me on 2019 Excellence in Public Outreach Award, in Reno, Nevada. Photo by Valerie Orth.
The long-awaited Field Guide to Freshwater Fishes of Virginia was released by Johns Hopkins University Press in September.  Many relevant lessons were learned while creating this new book. Ben Aaronovitch wrote, “There’s nothing quite like Latin for disguising the fact that you’re making it up as you go along.” Seriously, getting all the scientific and common names correct and up-to-date was harder than we expected.   New fish facts are discovered each day and we may not learn about them unless and until we attend fish conferences.  Get a copy and learn what's new in the world of Virginia's freshwater fishes.  Book reviews by Matthew L. Miller,  Bruce Ingram, and Scott Smith (2019) suggest that you shouldn't collect fish without it.
Field Guide to Freshwater Fishes of Virginia was published in September 2019.   Photo by Pat Cooney. 
Even the Hokie Bird needs a copy of the Field Guide. Photo by Valerie Orth.
I wrote a 38-page letter (March 15, 2019) to the Federal Energy Regulatory Commission (FERC) in response to their request for input on study plans for re-licensing the Byllesby-Buck Dam Hydroproject Pre-Application Document (FERC NO. 2514). There's no place to put this in the eFAR--it's "other professional activities." However, environmental effects of the hydroproject operations will be altered because the power company installed new gates that allow more control of water levels.  Consequently, new studies are needed during the re-licensing process so that FERC may balance environmental protection and power production.  These two dams block the upstream migrations of many fishes, including the Walleye, a unique strain and the target of restoration. Walleye eggs from this unique river-spawning population have 65% larger volume, an adaptive trait for living in less productive waters. Byllesby and Buck dams flood presumed historic spawning habitats and block their migrations.  For more relevant background on the New River ecosystem, read this conference paper from the 2019 New River symposium
Buck Dam and bypass reach. Photo taken March 20, 2019 by Don Orth.
Former and current lab members are moving on. Corbin and Lindsey Hilling were blessed with the birth of Penelope Hilling (photo below).  Rebecca Bourquin defended her Master's thesis, Genetic Diversity and Population Fragmentation of Chrosomus sp. cf. saylori (Clinch Dace). Ryan McManamay, PhD 2011, left his position at Oak Ridge National Laboratory, and moved to become an Assistant Professor at Baylor University in August.  Zach Moran, BS 2015, began a PhD program at Baylor University.  Hunter Hatcher, BS 2016, left Florida Fish and Wildlife Commission to take a Fisheries Biologist position with the Virginia Department of Game and Inland Fisheries in Farmville.   Skylar Wolf, BS 2017, completed his MS at Oklahoma State University and begins a new job as fisheries biologist at the Utah Division of Wildlife in Logan, Utah.
Penelope Hilling was born on October 30.  Congratulations to Corbin and Lindsey. 
The top viewed blog post of 2019 was How Old Do Flathead Catfish Get? This post was relevant to over 1,700 viewers.  In June, Timmy Dixon posted a photo (below) of a 62 pound Flathead Catfish caught on a trotline in the New River.  This photo generated much interest because Smallmouth Bass, not Flathead Catfish, are the top targeted sport fish in the upper New River.  Flathead Catfish are targeted by trotline fishers in a hidden fishery.  Corbin Hilling removed the otolith and counted 25 annual rings. The hidden population of Flathead Catfish is well known by trot liners and those who SCUBA dive in the New River.  Watch this short underwater video by SCUBA divers in the deep whirl hole in Eggleston, Virginia (video posted by Charles Horton).  Many other relevant writings for the general public were posted in
Flathead Catfish caught in July 2019 from New River near Fries, Virginia. For comparison, Timmy Dixon (pictured here) stands 6 feet, 4 inches
Finally, the Fluvial Fishes Lab was renovated in 2019.
Here is a photo during the renovation.
Fluvial Fishes Lab in September.

Relevant Publications in 2019 (I can pluck these right into my eFARS!)

Bugas, P.B., Jr., C.D. Hilling, V. Kells, M.J. Pinder, D.A. Wheaton, and D.J. Orth. 2019.  Field Guide to Freshwater Fishes of Virginia.  Johns Hopkins University Press, Baltimore, Maryland.  200 pp.  
Hilling, C.D., A.J. Bunch, J.A. Emmel, J.D. Schmitt, and D.J. Orth. 2019. Growth and mortality of invasive Flathead Catfish in the tidal James River, Virginia. Journal of Fish and Wildlife Management 10(2):641-652.
Orth, D.J. 2019. Socrates opens a Pandora’s Box of Northern Snakehead issues. Pages 203-221 in J.S. Odenkirk and D.C. Chapman, editors.  First International Snakehead Symposium. American Fisheries Society Symposium 89, Bethesda, Maryland. 
Orth, D.J. 2019. Fish, fishing, and ecosystem services and dysfunctions in the New River.  New River Symposium. Boone, North Carolina.  18 pp.
Schmitt, J.D., B.K. Peoples, L. Castello, and D.J. Orth. 2019. Feeding ecology of generalist consumers: a case study of invasive blue catfish Ictalurus furcatus in Chesapeake Bay, Virginia, USA. Environmental Biology of Fishes 102:443-465.  
Schmitt, J.D, J.A. Emmel, A.J. Bunch, C.D. Hilling, and D.J. Orth. 2019. Feeding ecology and distribution of an invasive apex predator: Flathead Catfish Pylodictis olivaris in subestuaries of the Chesapeake Bay, Virginia, USA. North American Journal of Fisheries Management 39:390-402.  
Schmitt, J.D., B.K. Peoples, A.J. Bunch, L. Castello, and D.J. Orth. 2019. Modeling the Predation Dynamics of Invasive Blue Catfish Ictalurus furcatus in Chesapeake Bay. Fishery Bulletin 117(4):277-290.  
Stang, S.A., C.D. Hilling, and D.J. Orth. 2019. Lessons learned from 35 years of students organizing the mudbass classic. Fisheries 44(3):115-117.
There are so many ways to disseminate research findings so that they are are relevant to broader segments of society (below).  The bewildering number of options may discourage one from the activities entirely. However, it is our personal responsibility to make choices about the audience and mode of communications to be used.   
Possible approaches to research dissemination arrayed by size of audience and mode of communication.  From Gould et al. (2019).
So it's time to celebrate the end of 2019 and the end of the decade of the 2010s. This 'Slow Professor' plans many more timeless times, detours, and delays in 2020.  Timeless times are needed for me to think critically and creatively. These slow times counteract the notions of efficiency, productivity, and speed that creep into the corporatized university.  Things may not go as hoped, but that's okay.
from Berkeley Breathed


Berg, M., and B.K. Seeber. 2017. The Slow Professor: Challenging the Culture of Speed in the Academy. University of Toronto Press. 136 pp.  
Gould, R.K., K.J. Coleman, D.H. Krymkowski, I. Zafira, T.Gibbs-Plessl, and A. Doty. 2019. Broader impacts in conservation research. Conservation Science and Practice DOI: 10.1111/csp2.108
Smith, S. 2019. Review of Field Guide to Freshwater Fishes of Virginia. American Currents 44(4):27. 
Watterson, B. 1988. The Essential Calvin and Hobbes: A Calvin and Hobbes Treasury.  Andrew McMeels Publishers, 256 pp.


Friday, December 6, 2019

The Future of Fishing, by Don Orth

A recent essay in the Wall Street Journal asked “Does fishing have a future?  It narrowly focused only on one type of fishing—sport fishing.  Participation in fishing continues to grow but not as fast as the costs to provide access to fishing opportunities.  Recent initiatives have marketing recreational fishing to newcomers because new participants to fishing are offset by similar loss of fishing participants (RBFF 2019).   There is no question that fishing has a future.   However, there are many futures to consider.

Fish and fishing support human livelihoods, food security, recreation, ecosystem functions, and human health and well-being in many ways. However, conservation is complicated because there are so many types of fishing and their distribution overlaps with so many types of human settlements and human activities.   None of these activities has as profound an effect on fish than fishing.  Humans have been capturing fish for tens of thousands of years. Stone Age burial heaps in Africa contained harpoons, spears, fish bones, and a wide range of terrestrial animals dated from 90,000 to 75,000 years BP, but it’s only in the last 1,000 years that humans have developed a pervasive culture around fishing for profit. Today, there are many types of fishing. To manage fishing, one must first understand the types of fishing, fishers, and communities, in order to consider from a diverse array of management actions.  By definition, fisheries are based on the capture of fish or shellfish, even if there is the possibility of their release after capture.  Even though we’ve been fishing for a long time, we still can improve how we manage fishing.
George's Bank Cod fishery.

Commercial fishing is the activity of catching fish or other seafood for commercial profit.  Fisheries employ 260 million people and fish are the primary protein source for ~ 40% of the world’s population (FAO 2016).  Over the past 50 years, annual global consumption of seafood products per capita has more than doubled, from almost 10 kg in 1960 to over 20 kg in 2014 (FAO 2016).  Many nations rely on imports to meet national demands for seafood products, which complicates the management of commercial fishing at national level.   Much of the fish harvested for fish meal or fish oil enters international trade markets rather than local markets. Paul Greenberg in Four Fish: The Future of the Last Wild Food (2011) describes commercial fishing as the last wild harvest of wild food, focusing on four fish (bass, tuna, cod, and salmon) that are most commercialized.

Global trends in capture fisheries and aquaculture FAO (2016).

Recreational fishing uses a variety of gear types including rod and line to catch fish for fun and or food.  Recreational fishing is defined as the fishing of aquatic animals (mainly fish) using one or more of several possible techniques in which aquatic animals do not constitute the individual’s primary resource to meet basic nutritional needs and are not sold or otherwise traded on export, domestic or black markets. The objective of recreational fishing is the overall recreational experience, and catch is only one important component. The propensity to harvest or to engage in voluntary catch-and-release varies among cultures, locations, species, and fisheries.  Outdoor recreation in general and sport fishing in particular are growing enterprises that contribute greatly to the overall economy.   Licenses and boat registration, taxes on boat motor fuel, and fishing equipment provide the funding for recreational fisheries management programs.  Recreational angler motivations change over time from catch any, to catch many, to catch big fish, and finally to catch no fish but pass on knowledge and passion for fishing. At some point many successful anglers wish to help others catch fish or to help researchers better assure that the fish and fishing experiences enjoyed in the past will still be around well into the future.
Recreational angler fishing a dusk.  Source Max Pixel
Traditional small-scale fisheries are prominent in many parts of the world. These artisanal and subsistence fisheries generate about one-third to one-half of the global catch that is used for direct human consumption (Pauly and Zeller 2016) and employ more than 99% of the worlds 51 million fishers (Jones et al. 2018).   Small-scale fisheries may also be described as (1) subsistence; (2) aboriginal, or (3) artisanal fisheries.  Subsistence fisheries are local, non-commercial fisheries, oriented not primarily for recreation but for the procurement of fish for consumption of the fishers, their families and community.” (Berkes 1988).  Subsistence fishers may forever be the ‘‘forgotten step-child’’ in fisheries management and are adversely affected by the attention lavished on the commercial and recreational sectors.  

Salmon and char are caught in gill nets by subsistence fishers in northwest Alaska Photo NPS  source
The diversity of fishing practices and take complicates conservation and management strategies.  We don’t often appreciate the diversity of fishing practices and behaviors.  While we know there is no such thing as the average angler or the average boat or typical fishing day, we often assume as much to simplify analyses.   Regulations on fishing must be compatible with the type of fishing.   Effective management and conservation require that we know our fishers well because the diversity of perceptions and fishing styles influence how they will comply with fishing regulations. 

Back to the question “does fishing have a future?”   The answer is yes, fishing has many futures.

First, marine commercial fisheries are frequently assessed  because catching capacity increases and new catch information is constructed (Branch 2011; Pauly and Zeller 2016). Big data, electronic monitoring, and artificial intelligence will influence future commercial fishing. Large valuable commercial fisheries are better managed via catch shares, and consumers are beginning to demand ecolabelled seafood (Lim et al. 2018).   The future of commercial fisheries will persist due to an ever rising demand for seafood, in particular tuna, but it will be harder for newcomers to enter into commercial fishing.

Second, the future of subsistence fishing is most uncertain because of a lack of monitoring. Consequently, food security for millions is at risk in the small-scale fisheries where the dominant protein sources is from locally caught seafood.  The long-term future of many subsistence fisheries will depend on our global efforts to address effects of global climate change on many islands. For example, consider the Atafu atoll in Tokelau (below) where all households participate in fishing and local reef fishes are a vital component of diet and tradition (White et al. 2018).  Effects of warming on reefs will have a substantial influence on subsistence fishing here and many similar islands.

An aerial view of Atafu atoll in Tokelau. It is the smallest of Tokelau’s three atolls with a land area of only 2.5 square kilometers. Photo:NASA
Finally, recreational fisheries on traditional species, such as trout, walleye, and bass, can be better evaluated. Avid anglers adapt and switch fishing locations depending on their perceived success. With a few exceptions, the general public is unaware of the status of fish that support recreational benefits, especially in urbanized regions where a minority of residents fish. And there’s the dilemma. Better monitoring and management will happen only if people show political will and desire to demand it. If the majority of the population does not fish then there’s insufficient support for fishing. The future of recreational fishing is expanding to non-traditional species.  For example, microfishing targeting many species as opposed to many fish are on the rise. In Mark Miller’s Fishing Through the Apocalypse, he provides a number of vignettes that illustrate how fishing in unusual places in our increasingly human-dominated world can provide new experiences.  


Berkes F. 1988.  Subsistence fishing in Canada: a note on terminology. Arctic 41(4):319–20.
Branch, T.A., O. P. Jensen, D. Ricard, Y. Ye and R. Hilborn, 2011 Contrasting global trends in marine fishery status obtained from catches and from stock assessments Conservation Biology 25:777– 786, DOI: 10.1111/j.1523‐1739.2011.01687.x.
Food and Agricultural Organization of the United Nations (FAO)  2016. The State of World Fisheries and Aquaculture
Jones, B.L., RK.F. Unsworth, S. Udagedara, and L. C. Cullen-Unswrorth. 2018.  Conservation concerns of small-scale fisheries: by-catch impacts of a shrimp and finfish fishery in a Sri Lankan lagoon.  Frontiers in Marine Science
Lim, K.H., W. Hu, and R.M. Nayga, Jr. 2018.  Is Marine Stewardship Council’s ecolabel a rising tide for all?  Consumers’ willingness to pay for origin-differentiated ecolabeled tuna. Marine Policy 96:18-26.
Pauly, D., and D. Zeller. 2016. Catch reconstructions reveal that global marine fisheries catches are higher than reported and declining.  Nature Communications 7, 10244.
Recreational Boating and Fishing Foundation (RBFF). 2019.  2019 Special Report on Fishing.  75 pp.  Available at
  White, R., A.R. Coghlan, A. Coulter, M.L.D. Palomares, D. Pauly, and D. Zeller. 2018. Future of fishing for a vulnerable atoll: Trends in catch and catch-per-unit-effort in Tokelau’s domestic marine fisheries 1950-2016.  Frontiers in Marine Science 5:476.  doi: 10.3389/fmars.2018.00476

Thursday, November 21, 2019

Aphrodisiacs are Bad for Sustainable Fisheries, by Don Orth

Why are some fish and some fish products more valuable than others?  While the news media focuses on trade bans in shark fins, and seahorses, the swim bladder (or fish maw) is also a prized fish part.  Selling fish maw may initially appear to be a win for the fishers.  However, when fish maw is believed to possess mystical qualities, the swim bladder becomes the target of a global trade network. 

Swim bladder of the Rudd Scardinius erythrophthalmus. Photo by Uwe Gille.  CC-BY-SA-3.0. Source. 

Swim bladders (also called a gas bladder) are flexible-walled, gas-filled sacs that control fish buoyancy and may aid in hearing.  Swim bladders are only present in bony fishes and are rarely saved in most fisheries. Fish swim bladders are high in collagen and can be turned into glues. Nutritionists maintain that collagen can reduce joint pain and treat skin ailments. Sturgeon swim bladders were turned isinglass for clarification of beer before other alternatives emerged.  In some Asian cultures the swim bladder, or maw, of fishes is considered a delicacy, and dried fish maw may sell from between $20,000 and $80,000 per kilogram.  Why is the price so high?  Does it have special medicinal or aphrodisiac qualities?   Fish maw is eaten to strengthen one’s qi, or internal energy.  However, there is no evidence that fish maw is an aphrodisiac. 

Display of fish maw at Singapore festival. Photo by Too Yut Shing,  Flickr

It’s difficult to study trade in fish swim bladders because of the global nature of trade and lack of reporting. The fish species harvested for the maw product is also challenging to identify. Since 2015, the fish trading in Hong Kong introduced a new commodity code, called “maw.”   Between 2015 and 2018, 3,144–3,882 tonnes of dried fish maw was imported annually to Hong Kong (Sadovy de Mitcheson et al. 2019).  These dried imports had a declared value of $264–394 million US dollars.  

Largest fresh specimen of Chinese Bahaba, caught on 30 December 1993, outside Castle Peak Bay, western Hong Kong, as incidental trawler by‐catch (Sadovy and Cheung 2003). 
Fish maw is used more for its unique texture and ability to soak up other flavors. It is almost tasteless in itself.  Consequently, fish maw is used in many soup recipes and often substitutes for shark fins. As a delicacy, demand for fish maw means that many fish stocks around the world may be at risk to overfishing in order to meet this demand. Depending on the fish, it may take 25-35 pounds of fish to yield a pound of swim bladder.  Therefore, the most prized fish maw often comes from large fish, many of which are croakers (Sciaenidae). The Chinese Bahaba Bahaba taipingensis is a critically endangered species due to unregulated fishing and harvest of immature individuals (Sadovy and Cheung 2003).  

A porpoise, vaquita (bottom) captured as bycatch along with a totoaba in Sonora, Mexico. Image by NOAA.

Among the imports to Hong Kong, most fish maw were large croakers (Sciaenidae), Nile Perch Lates niloticus, pufferfish (Tetraodontidae), catfishes (Siluriformes), and pike conger (Muraenesocidae). In many of these fisheries, the harvest of fish maw is unregulated Nile Perch Lates niloticus in Lake Victoria were harvested since first introduced in the 1950s (Ogutu-Ohwayo 1990) and locals ate fried maw until the lucrative Chinese market emerged.  In 2017, Uganda, Kenya, and Tanzania earned $86 million from trade in fish maw from Nile Perch.  Declines of fish harvested for their swimbladders have occurred in French Guyana and the Gulf of Mexico.  Without regulations, foreign fleets off Guyana throw back the fish and take only the profitable bladders. The Totoaba (Totoaba macdonaldi), a large marine fish that lives only in the Gulf of California, Mexico, is one of the most highly prized fish maws on the market. Like the Chinese Bahaba, the Totoaba can attain 2 meters and exceed 100 kg.  Consequently, Totoaba is critically endangered because of the high prices. Fishing for Totoaba has been banned since 1975 but illegal fishing continues.  The Totoaba fishery threatens a small porpoise, the vaquita Phocoena sinus, with extinction as it is captured as bycatch in gillnets (Bessesen 2018; Martinez and Martinez 2018).  

Bowl of fish maw soup.  from

High-valued fish may provide a lucrative revenue stream.  Unfortunately, the rarity of certain fish such as the Chinese Bahaba, makes its swim bladder even more valuable. The solution may lie in raising awareness of the status of rare fishes, and the illegal and unregulated fishing to produce fish maw.  Should there be a ban on trade in fish maw? That's likely overkill because of lower valued fish maw products.  The maw of the most highly valued species is valued at over $1,000 (US) per kg, and often much higher (Sadovy de Mitcheson et al. 2019). Bans do not eliminate fishing when the price for the produce is so high to produce a “gold rush” mentality.  The fisheries for the Chinese Bahaba and the Totoaba are easily overfished because the combination of high value of individual fish, restricted range, and spawning aggregations make fishing more of a gold rush than a sustainable enterprise.   


Bessesen, B. 2018.  Vaquita: Science, politics, and crime in the Sea of Cortez.  Island Press, Washington, D.C.  320 pp.
Martinez, I.A., and E.R. Martinez. 2018. Trafficking in Totoaba maw.  Pages 149-170 in I. Arroyo-Quiroz, and T. Wyatt, editors. Green Crime in Mexico. Palgrave Studies in Green Criminology. Palgrave Macmillan, Cham
Ogutu-Ohwayo, R. 1990. The decline of the native fishes of lakes Victoria and Kyoga (East Africa) and the impact of introduced species, especially the Nile perch, Lates niloticus, and the Nile tilapia, Oreochromis niloticus. Environmental Biology of Fishes 27:81-96.
Sadovy, Y., and W. L. Cheung. 2003.  Near extinction of a highly fecund fish: the one that nearly got away.   Fish and Fisheries 4:86-99.
Sadovy de Mitcheson, Y., A.W. To, N.W Wong, H.Y. Kwan, and W. S. Bud. 2019. Emerging from the murk: threats, challenges and opportunities for the global swim bladder trade. Reviews in Fish Biology and Fisheries   29: 809-835.