Field Notes: Barrens topminnow survey and collection

It may still be February, but the temperature has warmed and we're headed outside!  Yesterday, we joined staff from the Tennessee Aquarium for a day of field work to survey and collect Barrens topminnows (Fundulus julisia)- we call them BTMs for short.  We are some of the partners in an ongoing restoration effort for this imperiled Tennessee endemic species, a project that is unique in the amount of cooperation we have with private landowners, government agencies, and other nonprofits.

An adult male BTM.  Image courtesy of CFI

We met up with biologists from the US Fish & Wildlife Service and Conservation Fisheries, Inc. (CFI) at a site in rural Tennessee north of Manchester.  The site is a small spring and spring run that runs under a highway and through an adjacent cattle field--all on private land that we can access because of our cooperative partnership.  We split up into two groups and sampled different sections of the spring run.  For most of the length of the run the water was only a few feet across and rarely more than knee deep.  Using seines--long nets, each group made 12 hauls through different parts of the site.  All BTMs were set aside in a bucket and measured before being released after all sampling was finished.

The first group, who worked the upstream portion of the spring captured over 60 BTMs from juveniles through adult age classes.  That's a good indication because it shows there was breeding activity going at this site; a sign of a healthy population.  That same group also captured green sunfish (Lepomis cyanellus) and tadpoles in the seine hauls. 

Luckily, no western mosquitofish (Gambusia affinis) were captured this far upstream, hopefully indicating that this invasive species is not present in the spring.  Mosquitofish are a threat to BTMs because they can be aggressive towards the adults and actually prey on the juveniles.  Mosquitofish are one of the biggest continuing threats to BTMs across their entire range. 

The second sampling group was even more successful, surveying over 80 BTMs.  The second group did, however, capture mosquitofish.  Hopefully, the mosquitofish will not invade further upstream in the spring run.

Biologists surveying BTM populations in the field

We and CFI kept some of the adult BTMs from this site to use as broodstock in our ongoing captive propagation programs.


After sampling at the first site was completed, we piled into our vehicles and drove to another site a few miles north.  There, we accessed a small tributary to the same creek system that runs through a newer housing subdivision.  Pat Rakes, from CFI, recalled spotting a few BTMs during a quick visual survey of the site over a decade ago, and he wanted to see if they were still there.  Using a seine, we quickly collected a few BTMs and other small-stream fishes native to the area.  The creek appeared healthy, but the area immediately adjacent to the spring was being heavily impacted by development and will need close monitoring in the future.  A small number of fish were taken from this site, and we will use fin clips from them to analyze their DNA to see if they are a distinct population from the BTMs at the earlier site.

For Valentine's Day: Red is the "color of the deep"

In honor of Valentine's Day, today's post is dedicated to the color Red.  For humans, we often associate vibrant hues of red and pink with love and romance.  For deep sea fish and invertebrates, this same vibrant color is actually camouflage.  As light penetrates the surface of the ocean, the higher energy, longer wavelength red light is absorbed first.  That means that as you descend more than a few meters past the surface, all the red light is quickly absorbed.  With no red light present at depth, objects that are red in color appear drab and grey. 



Visible spectrum attenuation as a function of depth.
Taken from http://marineodyssey.co.uk/abioticoceans.html





For animals that live at extreme depths, red becomes the perfect color for avoiding visual detection.  Furthermore, deep sea animals have lost the ability to see the color red making red colored prey (or predators) even more difficult to detect.  The Monterey Bay Research Institute (MBARI) posted a video on YouTube that shows lots of different deep sea animals which are Red in color.  Check it out!

http://www.youtube.com/watch?v=16wZSHPvVGI&feature=youtu.be

A Fishy Valentine's Day

Flowers? A box of chocolates? Maybe a fancy home cooked meal? How will you celebrate Valentine’s Day? While many of us humans spend the week leading up to Valentine’s Day fretting and fuming over how to best impress our loved ones, a look to some of our finned neighbors might provide some inspiration…

Breeding season for many North American minnows belonging to the family Cyprinidae is marked by drastic changes in the appearance of the males. As spring approaches and water temperature warms, males of many species begin to display vibrant colors to attract mates. Many of these fish live in clean, clear water where bright colors can be effective at communicating with potential mates. In addition to changes in color and behavior, in minnow species the males begin to grow temporary bumps over their heads (and bodies and fins of some species). The exact function of the bumps, sometimes called nuptial tubercles, is not fully understood, but it is believed they are used for nest defense and for stimulation of their mate.

Males of the minnow genus Nocomis, commonly referred to as chubs or horny heads, use nest building with stones to impress their mates. Minnows of this genus are nest builders- constructing nests made first by excavating a pit in the substrate. Once the pit is dug a male will coax a female to enter the pit where mating occurs. Once the eggs have been released and fertilized the male then fills the pit with larger river stones protecting the fertilized eggs from predators and from being smothered by silt. These larger stones provide more space so clean, oxygen rich water can flow over the nest. The male then aggressively guards the nest from other fish who may attempt to prey on the eggs.

Crayfish Diversity

The flora and fauna of North America is among the best-studied on Earth, yet scientists continue to make remarkable discoveries in our own backyard. Just this month, scientists announced the discovery of a giant crayfish—the Tennessee Bottlebrush Crayfish--from Shoal Creek on the Alabama-Tennessee border. However, this new species is remarkable only because of its size--up to 5 inches long! Since 2000, at least 33 species of crayfish have been described from North America, including at least five from Tennessee.

This represents most of the diversity of crayfish worldwide. The family Cambaridae, which most southeastern species belongs to, has around 430 species, of which seven occur in east Asia and the rest in eastern North America. Crayfish from west of the Continental Divide are in the family Astacidae (~16 spp.), which also occurs in Europe and the Mideast. A third family, the Parastacidae (~180 spp.), occurs in the Southern Hemisphere.

Our knowledge of many invertebrate groups is still in its infancy. The southeastern US has extremely diverse communities of aquatic snails, mussels, caddisflies, and many other insects. Even well-studied groups like freshwater fishes and amphibians still see new species described on a regular basis. Because these animals serve as an important component of aquatic food chains and affect ecosystem structure and function, it’s critical that we continue to study and conserve them.

-Dr. Dave Neely

What We’re Reading at TNACI: Four Fish by Paul Greenberg

Every other month, TNACI Director Anna George leads an informal book club discussion with interested aquarium staff and volunteers on books covering a range of environmental topics.  Below is her quick book review...

The Aquarium’s Environmental Book Club met this past Wednesday to talk about a great book, Four Fish. Paul Greenberg, a lifelong fisherman, examines the toll that human consumption is having on our “last wild food.” Though the oceans were once thought to be limitless, the growing human population and our increasingly advanced technology have pushed many species to commercial, if not actual, extinction. With in-depth studies of salmon, Mediterranean sea bass, cod, and tuna, Greenberg covers the many challenges that our fisheries face, both farmed and wild. His practical conclusion offers some well-thought recommendations to how we should approach fisheries and aquaculture in order to sustain the supply.

Here's a link to the author's website:  http://www.fourfish.org/

Future book club gatherings will discuss:

March:  Silent Spring by Rachel Carson. The book that started the environmental movement by addressing the ecological impact of pesticides.

May:  King of Fish by David Montgomery. The history of salmon in Europe and eastern North America and the future of salmon in western North America.

July:  The River Why by David James Duncan. A novel on fishing, living in harmony with nature, and seeking knowledge.

September:  Living Downstream by Sandra Steingraber. An analytical memoir about the rise of cancer and and chemicals in the environment.

November:  The View from Lazy Point by Carl Safina. A discussion of the impacts of global change on marine life around the world.

Annual Lake Sturgeon Reintroduction Working Group Meeting

We just wrapped up our annual Tennessee Lake Sturgeon Reintroduction Working Group meeting where all the working group partners convene to discuss strategies, ideas, solve problems, and report on their programs' successes as we work to reintroduce lake sturgeon into the Tennessee Rivers.  The Saving Our Sturgeon program is now in its second decade and we've released 108,785 fish into the Tennessee and Cumberland River systems.  In 2010 alone, Saving Our Sturgeon partner organizations released 16,806 lake sturgeon in the Cumberland and Tennessee Rivers- over 3,200 of which came from TNACI! 

A number of agencies were represented at today's meeting including US Fish & Wildlife, TWRA, TVA, USGS, TTU, and TNACI.  Georgia DNR has a similar program to restore the lake sturgeon population in the Coosa River system and they sent representatives to compare notes and share ideas.

During the meeting each agency gave a quick overview of the past year's activities.  We also discussed future stocking plans, some outreach and education events, and an increased focus on monitoring fish once they are released.   Future stocking efforts will likely include emphasis on releasing bigger fish.  To release bigger fish, hatcheries must invest more money, space, and labor, but we think the extra investment will pay off in the long run with higher survival rates.

Keep posted for more program updates on Saving Our Sturgeon.  We expect to be receiving our 2011 fish in the first week of June...less than six months away!

Chef Barton Seaver discusses sustainable seafood

Below is a link to a TED Talk video of Chef Barton Seaver who has some novel (and simple!) ideas on how to eat sustainable seafood. According to Barton, simply eating the “right” kinds of seafood isn’t enough. To truly eat both more healthily as well as more sustainably, we need to also look at our portions of protein that we get from seafood. Watch his talk at the link below to hear his ideas for yourself.


www.ted.com/talks/lang/eng/barton_seaver_sustainable_seafood_let_s_get_smart.html


www.bartonseaver.org/story.html