Saturday, May 25, 2013

Candy darters (Etheostoma osburni) in Big Stony Creek

Below is a short video of the elusive candy darter, native to the New River drainage.

Virginia has an excellent variety of native fishes primarily due to the diversity of aquatic habitats. Several large Chesapeake bay tributaries begin on the eastern slope of the Appalachians as cold upland creeks, gaining volume and strength before emptying into the Bay. Headwaters may begin as a native brook trout stream but their ecology may change drastically, ultimately ending up (like the mighty James River) miles across and home to oyster reefs and a variety of saltwater species. But many Virginia rivers and streams do not end up in the Bay. In the western portion of the state, several large rivers - the North and South Forks of the Holston, the Clinch and the Powell - are part of the Tennessee drainage, while the ancient New River flows northward into West Virginia and becomes part of the Ohio drainage. The Roanoke River flows southward into North Carolina and ends up in Albemarle Sound. 

Roanoke logperch are native to just a few small sections of water in Virginia

Each of these rivers and drainages have a unique geological and cultural history, but also have fish species unique to them alone.Unfortunately, many of these species have evolved to rely upon their specific habitats within these rivers. Over time they may become isolated in an ever shrinking portion of habitat within their native rivers. An excellent example of this is the Roanoke logperch; this Threatened and Endangered species suffers primarily from habitat loss and degradation related to human activity along the banks of the Roanoke. The constriction of habitat often begins the slow doom of such creatures that literally have nowhere else to go. Not only are these fishes in jeopardy, but the cold, pristine streams they require is also getting harder and harder to find.
 The candy darter Etheostoma osburni is truly eye candy to native fish lovers

Recently Nick Little, Senior Aquarist for the National Aquarium in D.C. and I went in search of one of the rarest and arguably the most beautiful of all the darters, the candy darter Etheostoma osburni. This darter is native only to the New River drainage and is found in such limited areas and small numbers that it is listed as a Species of Special Concern, and is protected by law. We were driven by the desire to see these beautiful animals for ourselves, alive in their own habitat before they are gone. This may sound dramatic, but each year at least one spot I have previously enjoyed has been bought, bulldozed, or altered in the name of progress.

A pristine tributary of the New River

Although we are prohibited from collecting or displaying this species, as darter enthusiasts (nerds) the challenge was to find them, and then film them underwater.Unfortunately for us, they like gravelly beds in swift water, so our videos reflect the fact they are far more suited to such habitat than a couple of dudes in wet suits with one hand on a camera and 50 degree water flowing down your front.
Nick finds his soul mate; a female candy darter resting in the depression atop this rock
A male candy darter in the photo box

I put one of the photo boxes into action

Aside form the obviously beautiful candy darter there were many other excellent fishes, among them: the fantail darter, the Appalachia darter, mountain redbelly dace, an extraordinary population of crayfish, and the crescent shiner.
Appalachia darters are also native only to the New River system

Saturday, May 18, 2013

Seahorse breeding tank - babies meet parents!

Today we removed the partition that separated the lined seahorse parents from their young and they mingled together for the first time. The partition protected the young from being sucked against or into the filter system. As the video shows, the juveniles are two different ages; about three months apart. Seahorses love to cling to each other with their tails and often form chains of three or four seahorse all connected together, often attempting to move in different directions at the same time. In the above video they are feeding on live adult Artemia or brine shrimp, which they get many times a day, but also are fed Cyclopeeze and Mysis. Its easy to tell from the video why people like seahorses so much; they have a gentle and inquisitive nature - and are just a bit silly.

Saturday, May 11, 2013

White catfish (Ameiurus catus) spawning

This video shows a pair of our many white catfish spawning. These two have fanned out a shallow depression underneath some woody debris with their tails. They perform a ritual where they swim in circles side by side until they eventually are ready to mate. They press their sides together head to tail-tail to head and curl their tails around each other. They do this repeatedly for several hours: she deposits eggs and he fertilizes them.
A pair of white catfish

Catfish inhabit nearly every aquatic habitat across the world; a testament to their adaptability and biological success. As a group, they are one of the most important commercial food fishes and also extremely popular sport fishes, so it is no wonder catfish are so recognizable. Many tropical species are also quite popular in home aquaria (e.g. plecos, corydoras). Catfish are very recognizable because of their "whiskers" for which they are named. These are actually sensory organs - external taste buds - that help catfish detect food with amazing sensitivity..

The pale to white lower pairs of barbels help to distinguish the white catfish.
Brown bullheads have dark barbels.

In Virginia there are fifteen species of catfishes from two major Genera: the forked-tail catfishes Genus Ictalurus, and the bullheads Genus Ameiurus to which the white catfish (Ameiurus catus) belongs; within Ameiurus the subgenus Noturus contains six small stream species of catfishes called madtoms. White catfishes are the largest of the bullheads and, unlike the larger forked-tail catfishes, are native to Virginia. 

Brown bullhead Ameiurus nebulosus
Channel catfish (Ictalurus punctatus) were introduced in the late 1800’s, but the blue catfish (I. furcatus) and flathead catfish (I. puctatus) were introduced within the past fifty years, all as sport fish. Channels and blues especially have become so pervasive that they have out-competed the much smaller and less prolific white catfish in almost every body of water they share. 
This "white" catfish is actually an amelanistic channel catfish.

Saturday, May 4, 2013

Swamp Life - Merchant's Millpond - by Aquarist Patrycja Lawryniuk

In the upcoming weeks, fellow Aquarist Jillian Swinford and I will hopefully get out for our first big collecting trip of the year to Merchants Millpond State Park in NC - about an hour and 20 minutes from the VLM. Merchants Millpond is part of the Chowan River drainage, just south of the Great Dismal Swamp. It is an environment that melds swamp land and forestry together, housing many awesome critters like water snakes, numerous turtle species, mysterious insects, tons of birds, and of course fish. The VLM has only a few exhibits in which we can display these unique swamp denizens, such as the Pygmy Sunfish exhibit, and the Cypress Swamp, so its mainly for fun and the fishes are release unharmed. A few animals we may be looking for however, are the flier Centrarchus maropterus, the warmouth Lepomis gulosus and the swamp darter Etheostoma fusiforme.

Juvenile flier Centrarchus macropterus

Juvenile fliers have a very distinctive eye spot or ocellus (pictured above) that is quite unique. As adults, their fin configuration is very similar in shape to the crappies, but with very different coloration. Most people don't appreciate the simple beauty of these more "common" fishes, but each are interesting and attractive in their own way. A good example of this is the warmouth. Often lumped together as "sunfish" the members of the Lepomis family  may look very similar to each other, but the warmouth has "war paint" around the jaws, given them their name. Also, they usually have a slight purple sheen to them. Sunfishes make excellent display animals as they are hardy and get very accustomed to captivity due to their intelligence.

Warmouth Lepomis gulosus
Another interesting but seldom appreciated - or seen - fish is the pirate perch. Not a true perch, rather a species within its own Family Aphredoderidae. The family name is not a very attractive one, meaning "excrement throat" which describes the unique characteristic of this animal: their anus is positioned much farther forward than other fishes, all the way near its throat! These odd little fishes do NOT make good display animals as they are highly reclusive and nocturnal. But they are neat nonetheless.

Pirate perch Aphredoderus sayanus
The head of the longnose gar has many formidable teeth.
In addition to the small swamp species there are more recognizable large fishes like the longnose gar (above) and bowfin. Most fishermen discard these animals as trash fish, but they have earned their place in the toughest of environments, surviving for nearly 200 million years virtually unchanged. These "living fossils" can gulp surface air when necessary, allowing them to survive in the low oxygen waters of a southern swamp.

Cricket frog
There are even more creatures above the water. If you like snakes, this is the place for you. And of course if there are snakes, there are usually frogs - lots of them: green frogs, cricket frogs, tree frogs, bull frogs, leopard frogs. And many species of turtles, even an alligator!

Painted turtle Chrysemys picta