John Tullock Live

PBS Broadcast Spotlights Water Pollution Issues

Happy Earth Day!  Or maybe not so happy.

 

Yesterday (April 21) PBS aired the Frontline episode “Poisoned Waters.”  Details and clips have been posted, together with some of the press reaction.

 

The program provides additional evidence of the degree to which human development and other activities threaten our aquatic heritage.  Indeed, threaten our own survival.  Presenting scientific observations such as the discovery of frogs with multiple limbs and male fish producing eggs, the producers demonstrate once again the degree to which fish and other aquatic life become “first responders” to the pollution of waterways.

 

As one might expect, the industries responsible for the problems have their heads firmly buried beneath the sand.  In one of the highlights of the program, a poultry industry spokesman claimed, with a straight face, that nitrogen pollution finding its way into the Chesapeake Bay came not from the half million chickens housed in a factory farm on Virginia’s eastern shore, but rather from the wildlife in the surrounding woods.  This would be funny if it did not demonstrate such craven disregard for the common welfare in the name of profit.

 

The challenges faced by those who try to protect watersheds were made clear in another segment of the program.  In the region around Puget Sound, new land use regulations designed to protect the estuary have led to the formation of a committee of opposition.  Comprised of property owners disgruntled by the new restrictions, the group allowed Frontline reporter Hedrick Smith to tape one of their meetings.  During that taping one participant expressed surprised that residents have not resorted to violence in response to what he considered the unfairness of the new regulations.  This portion of “Poisoned Waters” made all too clear the intensity of perceived conflict between individual rights and public health.

 

All environmental issues are ultimately about land use.  In such matters, when water is involved, as it almost always is, activities far removed can create major impacts downstream.  Inevitably, property owners will try to assert their rights, and in many cases do so with little regard for the rights of their neighbors.  Such conflicts may well become the major focus of environmentalism in the 21st Century.  “Poisoned Waters” did not attempt to offer specific solutions to the problems it uncovered.  But it did make clear the urgent need to find answers to those problems, because our nation’s, indeed the world’s, waters cannot much longer bear the insults of unbridled development.

  

 

Bringing Back the Rare Logperches

Percina rex, the Roanoak Logperch

Among my favorite native fish species, the various logperches rank highly. A closely related group of large darters, the four species found closest to my home share an elongated snout and use it to flip over small stones in order to feed on the invertebrates found underneath. Conservation Fisheries has worked with all four of these logperch species and has enjoyed limited success in propagating them.

I mentioned Percina jenkinsi, the Conasauga Logperch, in an earlier post. Today's comments concern three additional species. Conservation Fisheries pioneered the idea of using “surrogate” species to develop captive propagation protocols. A relatively common and widespread species is selected for first attempts, so that the inevitable mistakes will not be made with another, much rarer species.

  In this case, the Common Logperch, Percina caprodes, has served as a surrogate for two of its far less common relatives. In learning how to rear common logperch, the biologists utilized techniques they developed for the culture of other darter species. Most of the difficulties stem from the problems encountered in working with the tiny, planktonic larvae.  Ultimately, over 1200 common logperch were produced.

Percina caprodes, Common Logperch.

An early beneficiary of the success with Common Logperch was the Blotchside Logperch, P. burtoni. Efforts to propagate this large darter began in 2004, with the collection of wild adults from Spring Creek, a tributary to the Hiwassee River. The intent was to restore populations to Little Tennessee River drainages. Eventually Conservation Fisheries succeeded in producing a few young. These are now on display at the Tennessee Aquarium in Chattanooga. Genetic analyses by Dr. Anna George of the Tennessee Aquarium Research Institute resulted in recommendations to utilize Little River as a source of parental stock for the effort. Little River fish were collected in 2007, but too late for any captive spawning. Hopefully, sufficient numbers will be produced for reintroductions this fall.

Blotchside Logperch, P. burtoni.

The large, impressively colored Roanoke Logperch, P. rex, is endangered. About a year ago, fourteen individuals were collected from the confluence of the North and South Fork Roanoke River near Roanoke, Virginia. They adapted quickly to captivity, swarming to the point where food was added to the tank whenever feeding was anticipated. With this species, too, it will be another season before Conservation Fisheries biologists are confident of their ability to rear them in large numbers.

   The logperches are but a few of the many fascinating fish that inhabit the streams of the Southeast. With continuing work by Conservation Fisheries and its partners, such as the Tennessee Aquarium, we can save these jewels of the mountains for future generations.

Native Fish Species Under Siege

Conasauga logperch, Percina jenkinsi

Here in the Southeast, we are sweltering through another year of drought. Some parts of the Cherokee and Pisgah National Forests, lying just east of where I live, are experiencing record low precipitation totals. To the west, the broad, flat Cumberland and Barrens Plateau regions are parched.

One can argue whether the dehydration of the normally rain-soaked Central South provides additional evidence of human-induced climate change, but among biologists studying the region’s aquatic wildlife there is no argument about its impact. Changes in weather patterns are affecting the breeding behavior of some native fish species, with spawnings occurring earlier than usual. Spawning behavior in many native freshwater fish species is regulated by temperature, daylength, or a combination. With the recent spate of hot summers, low water, and mild winters, the stream warms earlier, apparently signaling fish to start breeding.

Such behavioral changes could spell disaster. Although data are lacking about the early life history of many species, it is clear that fish larvae depend upon planktonic organisms for food. These tiny critters, such as copepods, rotifers, and protists, are themselves poorly understood ecologically. If the response of a key food species to warmer water does not match that of the fish predator, the latter may be in trouble. Sufficient research to understand fully the ecology of a single small stream could take decades, and we clearly do not have that much time.

Research is badly needed in order to better understand the ecology of the beautiful and unique freshwater fish fauna of the southeastern United States.  In particular, the Tennessee, Cumberland, and Mobile river basins harbor especially rich fish faunas, with many endemic species.

Consider the tiny Conasauga River watershed.  It is located where Tennessee, Georgia and North Carolina meet. It is roughly 100 times smaller than the combined watersheds of the mighty Colorado and Columbia rivers. Yet, between them the two western drainage systems have 58 species of native fish, while the little Conasauga has 79. One example is the endemic Conasauga Logperch, Percina jenkinsi.

A disproportionate number of native fish species range over a small geographic area. This is unsurprising, since the dissected nature of the watersheds contributes to speciation in the first place. Some fish may be endemic to a single creek. The smaller its range, the more susceptible a species is to extinction risks.

Barrens Topminnow, Fundulus julisia

In special danger from the current drought is a species confined to only 3 Tennessee counties. Fundulus julisia, the Barrens Topminnow, will instantly be recognized as a killifish by many aquarium enthusiasts. Like most killies, the males far outshine the females in coloration. Restricted to the Barrens Plateau, the fish inhabits clear, spring-fed streams and relies on aquatic vegetation for spawning.  Now found at but a few localities, it is constantly threatened by habitat destruction and drought.

Due to recurring droughts over the past decade, some habitat has almost completely dried up, leading biologists to establish captive “ark” populations. The fish is easy to breed and the larvae can take live brine shrimp nauplii as soon as they lose their yolk sac. As long as sufficient space is available for growout ponds, the Barrens topminnow can survive even the total loss of its habitat, at least temporarily. Populations are currently being maintained at multiple locations, against the possibility of a total wipeout at one facility. Questions remain about the sufficiency of captive propagation measures to maintain adequate genetic diversity, while at the same time preventing gene flow that would not occur in nature, i.e, between individuals from otherwise isolated populations.

Drought is not the only problem affecting the Barrens topminnow. It competes poorly with the mosquitofish, Gambusia affinis. Gambusia has been widely transplanted for mosquito control, but has become a pest in many areas, ousting native species. Ironically, one positive effect of drought has been to quell mosquitofish in isolated areas. After one Barrens Topminnow site completely dried up in 1998, killing all the mosquitofish, the native fish could be restored a few years later from a captive ark population.

It has been my pleasure for the past two decades to associate with J.R. Shute and Pat Rakes, co-directors of Conservation Fisheries. Their work with the Barrens Topminnow and Conasauga Logperch inspired this post. Credit for the accompanying photos goes to J.R. Shute. During 2007, Pat and J.R. reached a milestone: 50 species of native freshwater fish successfully spawned and reared. Much of its work is funded by state and federal wildlife agencies and private grants, but Conservation Fisheries survives on the support of individual donors. You can learn more about Conservation Fisheries at www.conservationfisheries.org

Green Aquariums - Why We Need Them

Redtailed Black Shark, extinct in the wild, but thriving in home aquariums.

Although I am no longer an aquarium retailer, I can imagine what most of my former colleagues are going through these days.

I won’t get into the debate as to whether we are now experiencing a recession or even something worse.  I’m no economist. By whatever name, however, in economic hard times one of the first segments to suffer is specialty retailing. Read that as Mom and Pop shops selling everything from model trains to scrapbooking supplies to dive gear and aquariums. The word I hear from friends in the aquatics industry is not encouraging.

Multiple factors surely lie at the root of the current industry slump, but one often cited is the lack of young people entering the ranks of hobbyists.  And one of the reasons given is the concern on the part of the younger generation for damage to natural ecosystems that sometimes results from the aquarium trade. 

Collection Guilt
In my experiences with aquatic wildlife conservation close to home, the youngsters seem to be coming along with as much enthusiasm as I had at their age. I continually meet recent high school and college grads who are well on their way to becoming the marine and freshwater biologists of the next generation. Virtually all enjoy aquariums, and view them as a valuable tool.

As an advocate for a greener aquarium industry for decades, I will not deny that the industry/hobby have done damage. The list of specific problems is serious:

* Overfishing, for example the Yellow Tang in Hawaii;
* Destructive fishing methods, such as collecting with cyanide;
* Targeting of non-adaptable species like Seahorses;
* and more. 

Both freshwater and saltwater players have contributed their share.  Nevertheless, the trend over the past two decades has definitely been toward a more sustainable industry.

Aquarium Rescues
In some cases, aquatic biodiversity has been preserved only because a particular species is popular with aquarists.  The freshwater cyprinid usually known as the Redtailed Black Shark, Epalzeorhynchos bicolor, is considered extinct in the wild, but thousands are shipped to the United States from Asian hatcheries every year.  Thus, this species survives only in aquariums.  Unfortunately, we have no way of knowing whether sufficient genetic diversity has been preserved to insure its long term survival. But at least it has not yet disappeared completely.

Captive propagation has also been responsible for eliminating wild harvest of many freshwater species, and will eventually reduce the demand for some wild marine species, as well. 

Marine enthusiasts will be the first to agree they have a long way to go.  Wild caught fish remain profitable to industry players at all levels, and consumer demand remains strong for many species that will probably never be produced in captivity. That said, the impact of all aquarium wild harvest is minuscule in comparison with the damage wrought by deforestation, pollution, storms, dredging and other causes.

Nevertheless, we should choose specimens wisely and avoid species that have little or no chance of adapting to captivity.  The obligately coral-feeding butterflyfishes, such as the Ornate Butterflyfish, Chaetodon ornatissimus, provide a perfect example. Catching, shipping, selling (and, for the hobbyist, buying) a fish that is going to die within weeks is wrong, and almost everyone involved knows it.

That said, home aquariums can do an enormous amount of good by bringing ordinary folks up close and personal with some of farflung tropical ecosystem’s most beautiful denizens.  A broader awareness of the fragile beauty sheltered within coral reefs and rainforest streams can only increase the desire to protect them for future generations.

This has certainly happened within the ranks of other hobbies involving nature. Tropical orchids and butterflies are produced largely in greenhouses or via special “wildcrafting” projects. 

Hope in Captive Propagation
In both cases, significant technical obstacles had to be overcome in order to succeed. Orchids, for example, do not produce stored food in their seeds, and must be germinated on laboratory media in flasks. Most terrestrial butterflies feed exclusively on one or a few closely related species of plants.  Like culturing algae to feed rotifers, you have to be able to grow the plant in order to culture the butterfly. Despite such challenges, the industries that support fanciers of orchids and butterflies are thriving. 

I was at my local farmer’s market recently and was stunned to find butterflies offered. We now have a butterfly farm in my town! I could, if I wanted, arrange to have native butterfly species released as part of a family celebration.

Only a few decades ago, collectors sometimes chopped down huge rainforest trees just to get the orchids.  Analogous to the poisoning of coral reefs with cyanide, such atrocious practices came to an end primarily because the ability to produce orchids from seed caused the cost of plants to plummet to levels affordable by ordinary people. When the saltwater captive propagation industry matures sufficiently, such will also be the case for it.

Successful Models

Saltwater breeders should look to the freshwater realm for a business model. 

At the moment, saltwater breeding is focused primarily on getting any species to the stage of development where it can be maintained on artificial foods. After that, growout becomes a matter of providing enough space to accommodate the thousands of offspring.  These are really two different operations. 

You might be able to spawn 20 different species with only 20,000 gallons of water, but you will need five times as much water for growout space, maybe more. In the freshwater realm, most of the labor-intensive spawning and larval culture occurs in Asia, where labor costs are lower. Maturing larvae are then shipped to the United States, often to Florida, where growout takes place in vast ponds. Florida, of course, has an abundance of level, sandy savannahs ideal for pond construction, and plenty of water (at least until recently). Something similar should work for saltwater, as well.

So, does aquarium keeping harm the environment? In localized instances, no question about it.

Overall, however, I am inclined to think the influence of aquarists and aquarium keeping on the preservation of aquatic environments is positive and becoming ever more important.

We have, over the past decades, quietly made the aquarium trade greener and greener, before "Green" was trendy. Concerned aquarists must make an effort to communicate this message to our younger generations.