Saturday, March 5, 2016

Virginia trout: Brook, brown, rainbow - from the hatchery to the exhibit

We display all three Virginia trout species: brook, brown and rainbow. Although brook trout Salvelinus fontinalis are the only native Virginia trout species (and our state fish), both rainbow trout Oncorhynchus mykiss (introduced from the western US) and brown trout Salmo trutta (introduced from Europe) have been in Virginia long enough (since mid 1800's) that they are now well established Virginians. Though they are still actively stocked for sport in many rivers popular to anglers, rainbow and brown trout often out-compete native brook trout and may even prey upon them when they share the same habitat. In some cases, efforts are underway to remove non-native trout and restore habitat of the wild brook trout.

Brook trout male (center)

Brown trout

Adult (4 year old) male rainbow trout 

Juvenile (4 month old) rainbow trout on exhibit acquired Tuesday from the hatchery 

From a husbandry standpoint each species has its own behavioral characteristics. Brooks are the easiest to keep; they are disease resistant, readily spawn in captivity, and are the most peaceful with each other and the other trouts. Brook trout are also strikingly beautiful, making them an excellent display species. Rainbows are simply eating machines: given the opportunity rainbows will eat until they can barely swim. Rainbows also tend to have more health issues than any native species we rear; they have long been captive bred for distribution throughout the the US and the world - for sport and for food - a factor that has made captive strains considerably less hardy. Aside from the fact that they are susceptible to disease, they are generally easy to keep as well. Browns are the outlier of the three. They aren't as overtly colorful as brooks, as well known as rainbows and  may vary widely in color and patterning: some browns are vivid gold with a plethora of black spots all over their bodies, while others may be drab olive-brown with little spotting. Regardless of their physical appearance browns have charisma. Thought to be the hardest to catch in the wild of the three trout species, they are the most reclusive and seemingly least tame. Browns have a tendency to hide, lay motionless much more frequently than brooks or rainbows, and will eat surprisingly large tank mates. And they jump! - out of the exhibit and sometimes into another. Several times overnight a brown trout has leaped into the Mountain Stream exhibit where they are found in the morning among the smaller stream fishes. Thus they require barriers to keep them from leaping onto the floor overnight. Did I mention browns are most active at night?

Brook, brown and rainbow trout on exhibit

All three trout species generally spawn in the spring and have traditionally done so on exhibit as well, driven by their internal clocks and triggered by the lengthening daylight in our glassed-in exhibit. However, trout are notoriously glutinous and gobble up each others eggs almost as soon as they are released by a female. Even if the eggs manage to hatch and mature, they rarely survive even a few weeks unless we remove them and raise them elsewhere. Trout grow very quickly with an abundance of food and they may mature in only a year or two. The males can become aggressive towards tankmates and may even seriously injure one another, which is not a good look for fish on public display. So we occasionally downsize our trout population and get younger, smaller trout from a local state hatchery...
View from Spy Rock a peak on the Appalachian Trail, accessed on Hatchery Road.

A side tributary of the Tye River, many of which are wild brook trout streams.

Montebello Hatchery is located just a few miles past Crabtree Falls (Tye River) and is also the access point to a hiking trail spur leading to Spy Rock on the Appalachian Trail. It is a beautiful area and the facility is open to the public. This hatchery raises all three species of trout and generously gives us fingerling trout when we need them. This visit we only needed only rainbows, with plenty of brooks and browns currently on exhibit. Below is a video of the rainbow trout fingerlings at the hatchery; we brought back about 200 of these guys!

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Thursday, January 7, 2016

"Fred" the nurse shark makes his debut


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Fred learns to eat (squid) of tongs while in holding

Our relationship with "Fred" began with an email. Our aquarium professionals' list-serve occasionally includes postings for animals that need to be rehoused for a variety of reasons. Most of these fishes have outgrown their tanks at private residences and need more space; this is most often the case with large freshwater Amazonian species (e.g. pacu, redtail catfishes, etc) or shark species. Well-meaning fish hobbyists purchase these animals while they are young and still small, but they soon find out these types of animals are simply going to be too large to keep as mature animals. Such was the case with Fred. A couple in Long Island, NY appealed to the nearby public aquaria which posted their request to the list serve for a new home. Sadly, common animal species often do not get placed but more desirable species often find homes quickly. Many that do not, are often released into the wild to pose a problem for native wildlife (e.g. northern snakehead, lionfish). Whenever possible we try to accept animals that we can take for the sake of all involved.

Lionfish (above) are an invasive species thought to have been introduced from escaped/released pets

I contacted the owners and after assuring them that he would be in good hands and would greatly benefit the animal to move from a 350 gallon tank to a 30,000 gallon tank. Thankfully for all involved they gratefully agreed to give us Fred, a three foot nurse shark, and we gratefully agreed to take him. But of course, you can't simply mail a three foot shark - a live one anyway - so we needed to go to NY to pick him up. Immediately. Their house on the water was being raised (because of what happened during Hurricane Sandy) and the power would be off for months. I scheduled Fred's pick up for two days later just after Thanksgiving. Our life-support set-up was a 300 gallon Rubbermaid trough tank with 12V re-circulation pump running water through an in-line carbon filter back to a spray bar return to the trough and additional aeration provided by three battery-powered aerators.

Corey checks systems on our transport bin before the trip to NY

The whole unit is covered with a heavy lid sealed at the edges with insulating foam to keep the system water tight (pictured above). We have used this system to successfully transfer many animals from large muskie to cobia to other shark species. Transportation of large fishes is common practice for public aquaria, but it is always stressful on the parties (people and shark) involved, albeit for different reasons. Long story short, Fred just rode the trip out quietly with plenty of space and traffic on 95 sucks,

Nurse sharks are a warm-water species and very common in the tropics but occasionally venture into temperate waters. They are one of the more sedentary shark species and largely nocturnal, laying still in on or near structure throughout the day and feeding by night.

Fred laying next to his favorite bucket in our holding tank - he often sleeps with his head in it.

Nurse sharks have an excellent sense of smell aided by barbels at the sides of their mouths, and peruse the bottom to feed on benthic invertebrates and crustaceans by sucking them from the substrate or simply crushing their shells. Nurse sharks are shy and docile to humans choosing to hide given the chance but are eager for food, making them an easy shark species to keep in captivity. Unfortunately, get too large - up to 200 lbs. - and powerful for any home aquarium in spite of their popularity. Fred's new tank-mates are a variety of native Mid-Atlantic species including: cobia, bluefish, jacks, triple-tails, grouper, a sandbar shark, black drum, and a loggerhead sea turtle.

Fred's soon-to-be tank mate - "Kay" the sandbar shark - is a more active shark species

Saturday, December 12, 2015

"Winter jelly-fishing" Lion's mane and Mushroom cap jelly collecting with videos

Mushroom cap jelly Rhopilema verrilli on exhibit




video
Mushroom cap jelly on exhibit

We attempt to mimic the seasonality of the Chesapeake Bay species through our exhibits whenever possible. The assemblage of fish species varies greatly during the year, but so do many other groups of animals; each local jelly species is associated with a particular time of year, or more accurately, water temperature. The onset of cooler water temps in late Fall/early Winter - usually below 50 F - triggers the return of the "winter jellies" or Lion's mane jellies Cyanea capillata which we gladly display at the VLM. This is the largest jelly species in our area, and the most colorful. Their name describes the furry mane-like lower bell structure that can be vivid crimson, pink, and peach that makes them a striking species on display.

Lions mane 

Most of the year we house sea nettles, which are the most common and frankly disliked jelly in our area, due to their frequent contact with swimmers. Sea nettles thrive in warmer waters and are an attractive species, but nowhere near as interesting or impressive as large colorful lion's mane. So each Holiday season, we anticipate their appearance and look forward to some quality "jelly-fishing" ala' Sponge Bob and Patrick. We have an excellent spot at historic Yorktown, and this year have been fortunate to have nearly 70 degree weather. 

Scanning the water for jellies - someone has to do it.
One more for the exhibit

Along with the unseasonably warm weather this year (is there really "normal" weather?), there has been an unusually large number of mushroom cap jellies Rhopilema verrilli. We have never seen this species in significant numbers, but there have seen quite a few this year and several very large specimens nearly 20 inches across! Such large jellies are impractical to display and likely would not thrive on exhibit, but this year we took the opportunity to display some of the smaller mushroom caps we saw (approx 10 inch bells) along with the lion's manes. Their bells and lower bodies are much more rigid than lion's mane making their movement less fluid with a quicker pulse than the lion's manes. They also have lower mouth/arms that look like clusters with gastric pouches beneath in lieu of elaborate, flowing tentacles. So far both have fed well and make for an interesting contrast in shape, movement and structure. 

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Saturday, October 31, 2015

New Muskellunge (Esox masquinongy), walleye and flathead catfish

One of our two new muskie on exhibit

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A muskie (the one pictured above) eats a 11" trout

We recently accompanied a Virginia Department of Game and Inland Fisheries (VDGIF) survey crew led by Biologist George Palmer, in the hopes of obtaining a muskellunge or "muskie" for our Mountain Lake exhibit. Adult muskie are truly impressive animals and can grow to nearly 5 feet long, but are notoriously elusive creatures so many people have never even seen one. Many fisherman and fish enthusiasts - like myself - can spend a lifetime having never caught one because of their finicky eating habits and unpredictability. They are ambush predators and lie motionless until unsuspecting prey meanders by. Using a heavily muscled, elongated body and armed with a duck-bill mouth full of spiky teeth, muskie can take down some serious prey. Aside from other fishes, they have been known to eat muskrats, frogs, snakes and even ducklings.

The duck-like bill of muskie hide some serious teeth

Biologist George Palmer (far left) and his crew

We met on the Upper James River where Mr. Palmer and his crew were scheduled to survey the river to get an idea of the fish species and their relative numbers that inhabit the river. There were plenty of catfish, good numbers of smallmouth bass and walleye, and of course muskie.

Several species of fishes (walleye in hand) were all weighed and recorded, then released unharmed.

Along with the muskie, we took advantage of our opportunity to also take a pair of walleye and a flathead catfish. The walleye is a large member of the perch family and is a very popular food and game fish in the Midwest, but not too common in VA. The flathead catfish may be best known for the species that some people go "noodling" for; a practice best described as finding a log, hole or tube that a flathead catfish has taken up residence - usually by feeling around in muddy water in rivers - then when you locate a flathead, you jam your hands in its mouth and pull it out of its hiding place.

The flathead catfish being measured above, now resides in our Cypress Swamp exhibit (below).


We'd like to thank VDGIF for allowing us the opportunity to join them on the river and specifically for helping us acquire these unique fishes for the public - and us - to enjoy.



Saturday, May 9, 2015

Seahorse genetics project

        The VLM is part of the lined seahorse SSP (Species Survival Plan), as part of the goal to "cooperatively manage specific, and typically threatened or endangered, species populations" by breeding seahorses at our facility and sharing/exchanging surplus with other institutions involved in the SSP. A major part of any SSP is research and the sharing of information regarding the species as well. Researcher Nancy Ho of the Vero Beach Marine Lab at Florida Institute of Technology heads a project that investigates the population dynamics and genetic diversity of lined seahorses in the wild; a project the VLM supports financially and helps to provide DNA samples from wild seahorses native to our area. 
A male seahorse (notice the pouch) is measured just prior to a fin clipping

        Whenever we are in the field and capture a seahorse, we record our collection location (co-ordinates, body of water) and retain the animal to get a tissue sample when we get back to the VLM. These wild sea horses have their own holding system specifically for this project, so they do not mingle with our captive bred population to insure that we can identify them as wild caught and that they don't interbreed. 


video
Sea horses like to stick together; here 8 of them lock tails on one small plant


        Samples are taken in a painless and non-invasive manner; we simply clip a 2 mm portion off the dorsal fin and save the fin clipping in ethanol. The entire procedure takes less than 30 seconds, causes the animal no pain, no loss of blood, and will grow back in a matter of weeks. The fin clipping is then sent to FIT, where Nancy can extract the DNA and determine what population the sea horses are part of. The wild seahorse can then be released back into the wild. Thus far we have submitted 17 samples for analysis and will hopefully be able to provide many more samples for her research.


Note the long fleshy appendages on their heads and along the backs

        Meanwhile the teenagers from our captive bred population are getting larger each day. They have graduated from Cyclopeeze and artemia to chopped mysis as well. this particular batch is extremely "branchy"(see picture and below); lots of long fleshy appendages, especially around the head. When these teenage horses are large enough and are trained to eat whole mysis from a feeding station, we will put them on exhibit. 
                                                            
Some of these guys are very ornate











                                                                                
                                                                                                                                     

Friday, May 1, 2015

Ruby Throated Hummingbird

Yesterday morning, animal keeper/trainer Carrie Bridgman found a lethargic and seemingly dazed  ruby throated hummingbird inside the River Otter exhibit. She brought the beautiful little creature inside our husbandry building to allow the otters into the exhibit without them having contact with it.  

It was immediately sheltered in a bucket with a baby blanket inside and another covering the top to give it some peace to rest and to hopefully allow it to recover enough to be re-released as soon as possible. I have experience with hummingbirds and volunteered (who wouldn't?) to monitor it's health. The first step being warmth on a cool spring morning and re-hydration - if necessary. As I prepared some warm sugar water for it, I heard it stirring inside the bucket. Knowing the fragile nature of this species and following the first rule of animal care - first do no harm - I wanted to make sure it did not injure a wing, so I immediately took it to a protected outdoors area behind the museum  in case it began to flap around or hopefully fly away; avoiding an injured or broken wing is the immediate concern. The hummingbird was going no-where for the moment, and simply rested with eyes closed. I then wanted to offer some water/sugar mix from a 1 cc syringe in case it needed some fluids. Aquarist Patrycja Lawryniuk thankfully was able to capture the little fella on camera. 

Just out of the bucket; a little subdued but content

It began to take solution slowly at first, but then very greedily. Thankfully the late spring sun came out just at the right time.

The refreshments and warm sun called for a short nap 

After 15 minutes or so of intermittent rest/feeding, it become much quicker moving and more alert. Eventually it took no more solution, looked around rapidly and flew into some nearby columbine.

It seemed to gather strength and become more alert minute by minute...

It then fed in nearly every flower for several minutes...

 flitting around faster and faster, and then it was gone, after a brief but ultimately successful encounter that I wont soon forget. 






Friday, March 6, 2015

Our new "Oyster Reef Ecosystem" exhibit: striped burrfish, blennies, skilletfish, spider crabs, etc.

Oyster reefs are one of the most productive habitats in the Chesapeake Bay; hundreds of species of aquatic plants and animals grow on and among their shells. The oysters themselves improve water quality and clarity by filter-feeding sediment and plankton out of the water while the natural accumulations of oysters that have settled upon the shells of their previous generations - essentially what constitutes "oyster reefs"- also serve as natural breakwaters that protect shorelines from erosion.

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A live oyster reef 
Last April, we partnered with Professor Russell Burke of Christopher Newport University to help him construct one of many artificial reefs he has installed throughout the Bay to help promote settlement and growth of the American Oyster in the wild. Wild oyster populations in the Bay are at an all-time low due to decades of over-fishing. The most critical current obstacles to their recovery are excess nutrients and excessive siltation that smothers the reefs and spat - or young oysters. By placing specially designed concrete "castles" and "diamonds" in strategic positions, spat can settle above the mud, and can now build one-on-another in an ever expanding reef.

"Before" Oyster castle with no oyster growth

"After" Colonized oyster castle

Last month, we constructed an exhibit to represent the "before" and "after" of an artificial reef. The left of the exhibit displays an unsettled diamond while the right side displays a diamond from an artificial reef Dr. Burke placed in the Bay seasons ago; the results are striking. Every square inch of surface area on the "after" diamond is completely covered in massive adult oysters and mussels, as pictured above. All of these shells in turn host: sponges, bryozoans, algae, amphipods, isopods, worms, crustaceans, and a large variety of fishes. It is a complete ecosystem in miniature!

the fishes living inside the oyster reef, 

along with feather blennies Hypsoblennius hentz.

Naked gobies Gobiosoma bosci live in the nooks 
and crannies of the reef.

picking at invertebrates in the oyster reef. 
Grey snapper Lutjanus griseus are effective predators of 
smaller fishes and inverts.

Oyster toadfish Opsanus tau are a stealthy ambush predator 
that often bury in substrate beneath the reef. 

Like the oyster toadfish, mantis shrimp Squilla empusa will hide in tunnels 
  they've dug around the rock, and ambush any prey that come along. 
Hermit crabs (long clawed on top, striped below) are 
very common scavengers in oyster rocks. 

himself with pieces of a beard sponge to blend into its environment. 

By displaying the tangible results of the restoration work, and the richness of the species that rely on them - not to mention the commercial worth of the oysters to humans - we are displaying what is at stake besides the fate of the oysters themselves: the health of the Chesapeake Bay. Once known for its natural riches, it is increasingly known for being a system badly out of balance; a system in which the American oyster once lay at the very heart.