Saturday, January 10, 2015

Lion's Mane Jellies - Cyanea capillata

The VLM displays a variety of jelly species: moon jellies, sea nettles and lion's mane. Fortunately for us, we are surrounded by the Chesapeake Bay and its tributaries. Several species of jellies are native here and tend to follow salinity and temperature conditions that best suit them. because of the large seasonal fluctuations and the different preferences of different jelly species, each season is dominated by one main species. Winter in the bay is prime time for lion's mane jellies. When the water temperature dips below 50 degrees F - usually by mid-December - they appear seemingly out of nowhere.
Lion's mane jellies have many long hair-like tentacles

Ice coats the jetty below the Coleman Bridge, Yorktown, VA

But actually their ephyrae, or juvenile form had already arrived and has been feeding and growing, morphing into the full blown medusa or adult jelly stage that most people recognize. The adult species of lion's mane jellies that frequent our area rarely get larger than a foot or so across and several feet long (still a big jelly), but in other parts of the world, lion's mane jellies can grow a bell over 6 feet across with tentacles stretching over 100 feet - the largest jelly species in the world! 


This lion's mane jelly on exhibit has a 5 inch bell and tentacles ~ 16 inches long

Each winter we anticipate arrival of the lion's manes and carefully monitor water temperatures in the nearby York River. We also have a network of members, staff, and volunteers of the VLM that report when they begin to see them. Perhaps the only jelly collector most people have ever heard of is SpongeBob SquarePants, but our staff is also out there with specialized "jelly" nets ready to collect wild jellies to augment our live collection throughout the year. Because of their size and beautiful colors, lion's mane are particularly desirable for exhibition. Unfortunately, January can be pretty cold on the water and this week was especially brutal. With air temps in the teens and wind chill near zero, it had better be worth it - and it was. We caught enough wild jellies to switch our exhibit from primarily sea nettles to lion's manes and will continue to display them and collect them throughout the winter.

 Sea nettles are more recognizable because they are here in the summer and are known for stinging swimmers. They even have a NOAA website dedicated to predicting their presence inshore.

Moon jellies do have tentacles, though they are much shorter than either nettles or lion's mane

Ctenophores or comb jellies are harmless and often luminesce at night

Like most jellies, lion's manes use their stinging tentacles to ensnare and subdue prey. In this area, they feed on virtually anything that becomes entangled in their tentacles as they flow behind the travelling jelly; it could be anything from zooplankton to small fishes. Here at the VLM we hand feed them daily a mix of Artemia nauplii and diced seafood such as shrimp, squid, or scallops. They will be on display throughout the winter and spring, when we will start gearing up for sea nettle season.






Saturday, December 6, 2014

Baby pipefish - video

video

Seahorses are instantly recognizable, but few people have ever seen or even heard of a pipefish. In fact there are three species of pipefishes in the Bay, and they are quite abundant. Northern, dusky and chain pipefishes all are found in the same general habitats in the Bay and coastal ocean: shallow, low-energy grass beds, or near-shore vegetation. Their unique coloration and elongate "pipe" shape - essentially a straitened out and stretched seahorse - gives them an uncanny ability to disappear among vegetation. Coloration can vary widely from dark brown to vibrant green, and they may be solidly colored or distinctly banded, which is more often the case with chain pipefish.

A pipefish tries to blend in 

Through camouflage and patience, pipefishes remain motionless and (hopefully) undetected waiting for unsuspecting prey to wander by. They also actively stalk prey by slowly and stealthily gliding through dense vegetation, propelling themselves with rapid undulations of their small dorsal fin and pectoral fins. This minimal motion is difficult to detect and does not betray their stick-like or grass-blade disguise. Just like seahorses, pipefishes use a long protrusable tube-like snout to slurp up small crustaceans such as amphipods and isopods; in fact seahorses and pipefishes are often found in the same areas.

A seahorse and a pipefish hang out together on exhibit. 

Both pipefishes and seahorses share many physical characteristics. Their bodies are very similar, though their swimming and resting orientation is different; seahorses are upright while pipefishes are horizontal. Both have a trumpet-like tubular toothless mouths, small pectoral fins, elongate bodies made up of bony rings much more evident in pipefishes (see above), very small dorsal fins, and a leathery brood pouch on the males which is distinctive only to the Family Sygnathidae (both pipefishes and seahorse spp.). Pipefishes have a rayed - fin tail, while seahorses have a prehensile tail to hold fast to structure and vegetation. Both Sygnathids can be a difficult to keep healthy in captivity mainly due to their specific diet, nutritional requirements and need for an almost constant availability of food. Juveniles and wild-caught specimens often don't transition to prepared foods well - if at all -, as they are naturally ambush predators and stationary foods don't trigger any innate hunting or feeding behavior. They can eventually be trained to take a variety of foods and can even be trained to a "feeding station", a specified area where food can be placed in a concentrated amount. Adult pipefish usually feed very eagerly on non live enriched foods, such as Cyclopeeze and Mysis, and breed often when healthy.

A two day old pipefish hunts Artemia nauplii...

Compared to seahorses of similar age (born Dec 11, 2014)




Friday, November 14, 2014

Deep Sea Fishes and Inverts: A Look Into "Beyond the Edge of the Sea" Exhibit

There are no places on Earth more foreign to humans than the depths of our oceans. The extreme pressure alone prohibits any normal vehicle from exploring their depths; but add to that the sheer enormity of space - almost 80% of the Earth's livable environments by volume are below 1000m deep - coupled with complete darkness and we have only a small glimpse so far of what lies beneath.

A few years ago I was fortunate enough to assist on a project led by Dr. Tracey Sutton who studied deep sea environments post-BP Deep Sea Horizon Spill, that also included a former employee Sarah Peake (now at GA Aquarium) and colleague Wendy Mooring. As a parting gesture Dr. Sutton donated some deep sea specimens to the collection here at the Virginia Living Museum. We temporarily use them during educational programs and seminars but to this point have not displayed them to the general public. Until now!

Close up of a small deep sea anglerfish

In another fortunate happenstance, Director of the Duke Marine Lab, deep sea explorer, former College of William and Mary professor, and long-time Alvin pilot Dr. Cindy Van Dover will be here at the VLM on November 15th to share some of her experiences and showcase her exhibit "Beyond the Edge of the Sea". This traveling exhibit features deep sea life and scenes witnessed in person aboard the Alvin that are beautifully rendered in scientifically accurate water color by artist Karen Jacobsen. Portions of her artwork are shown below:


                                           

We took this opportunity to publicly display several of our deep sea specimens for the first time. Below are a few of the preserved animals that you can see here alongside the beautiful artwork.

A display case of strange deep sea fishes and invertebrates

Threadfin Dragonfish Ethiostoma barbatum

Sloan's Viperfish Chauliodus sloani

Chimera

Porcupine Crab

Saturday, August 30, 2014

Striped bass and striper hybrids in our James River exhibit

September is the month we do our major exhibit work, including fish moves. Our first priority is to release any animals that will be too large to keep until next spring and replace them with smaller animals that can be kept comfortably at least until next collecting season. The first exhibits to down-size were the James River and James River Shallow exhibits. Earlier this year we added yellow perch that had grown too large for the Yellow Perch exhibit, and walleye that were transferred from the National Aquarium in DC when it (sadly) closed.

Two year old yellow perch
A walleye in James River exhibit

But we also acquired some captive bred striped bass (~30) and hybrids (~ 12 white bass x striped bass) from a hatchery to replace the adult striped bass which are the signature species in this exhibit. These hybrid and striper juveniles were initially about 4 inches when we got them but have been growing rapidly in our James River Shallow exhibit. They are now large enough to replace the striped bass adults in the main exhibit which have grown too large for the exhibit and were released last week. Below is a video of the very active school of stripers and hybrids just put in the main portion of the exhibit.
video
Stripers and hybrids school in their new exhibit

It is difficult to discern the hybrids from the pure bred striped bass, especially in the video. Generally, the hybrids demonstrate physical traits of the white bass that differ from pure bred striped bass: a higher shoulder profile, more irregular stripes, and a darker back in adults. All three species, white, striped, and hybrid are very aggressive predators and grow rapidly. Next spring we will have to remove a portion of this school to make room as they grow and by next fall we may have to start the process all over again.

The iconic striped bass


A hybrid striper 
Striper above, hybrid below

The shallow portion of the exhibit has been thoroughly scrubbed, cleaned, re-decorated and re-populated with a variety of smaller fishes and plants from our collection including a new female wood turtle taking the place of the irreplaceable "Woody" who recently passed away of old age.

"Woody" was the mischeivious, charasmatic long-time resident male wood turtle in James River

Thursday, June 19, 2014

Video of a massive mountain redbelly dace congregation

video
Occasionally when we are out in the field, we are fortunate enough to run across unusual or unexpected animals, or even better if you're far enough out there and get really lucky, you can witness unusually large groups of animals displaying natural behaviors and paying you no heed. In this case, a large shoal or "school" of nuptial mountain redbelly dace - with some rosyside dace, crescent shiners, and even a crayfish in there - have gathered on a chub nest to mate and are on full display. The beauty of these fish is hard to rival and create a living mosaic of red, gold, yellow, olive, black, white and silver.

Thursday, June 12, 2014

Mating season! Male redline darters fight it out, gilt darters mate, greensides mate

A large dominant male gilt darter in breeding colors

Late spring is breeding season for the majority of Virginia freshwater fishes; depending upon water temperatures, most darter species breed somewhere between early April to late May. Prior to (potential) spawning, male darters develop more intense coloration and exaggerated patterning than their normal appearance to outdo their male rivals in the hopes of attracting a female.
Male redline darter on display

Mature males will often spar with one another over territory or a single female, nipping at each others's fins and tails (see video below) often violently. Theoretically the dominant male wins out, but often the female pays either off them little notice and casually swims away as the males are still fighting. 
video
Two male redline darters fight over a female

Once a couple has paired off, they typically engage is some sort of courtship behavior that signals the beginning of actual mating. Many darter species show similar courtship and mating behaviors; for example the males of Genus Percina and many Etheostoma species as well swim alongside the female often weaving along her body from side to side, then when she settles into a good spot (presumably for laying eggs) he hovers over her and quivers his entire body so fast its a blur. Both videos below show this behavior from two species of each respective Genus. 
  video
Two gilt darters mate while a stoneroller watches and then rudely interupts

video
Two greenside darters mate and then also get rudely interrupted by a stoneroller

As seen in both video, these behaviors - at least in our stream exhibit - also trigger a feeding response in the other fishes looking for an easy meal of freshly lain eggs...or they are just excited by the activity. In either our exhibit or in the wild, successfully fertilized eggs face very long odds to reach maturity, but that's the reason these spawning events are so critical. They must find the right mate with good genes, create enough fertilized eggs to account for all the natural mortality, and spawn at a time when their young will have maximum food available as they grow. Because after their little spawning dance, mom and dad have done all they are ever going to do for their offspring. 






                                          




Friday, May 30, 2014

Barrel fish or drift fish - rare and unusual fish captured in shallow Virginia waters


Members of our husbandry staff were collecting on the Eastern Shore of Virginia last week and captured an unusual species rarely found in Virginia, especially near shore. This small saltwater fish at first appeared to be gold to orange-ish colored (see below), but overall color is a dubious trait to use for identification. Often fish under stress appear paler than their normal coloration, or may simply be an unusual color morph. It could not be identified in the field by its body shape either: disproportionately large eyes, an unusual fin configuration - stumpy dorsal spines with a larger soft dorsal element - down-turned mouth, and a blunt rounded snout. Thankfully, it was captured undamaged and brought back to the museum alive where we currently have it in one of our quarantine systems.
 The fish immediately upon capture

Just in the tank...

And most recently in its "natural" coloration.

This is obviously a small fish and one that presumably will not be of too much interest in a world of such recognizable and iconic fishes such as sailfish, white sharks and clownfish but that is precisely what is interesting about this little fish. To even verify what I suspected this to be - even the all knowing internet was of no help! - I consulted Dr. Kent Carpenter, a fish systematics expert and author of A Field Guide to Coastal Fishes: from Maine to Texas (my favorite Mid-Atlantic saltwater ID book) and he confirmed it belongs to the Genus Hyperoglyphe and is either a barrelfish or black driftfish, which are very similar species at this life-stage. There is very little information on either species and even less ecological information available (e.g. diet, temperature tolerances, etc); the basis for good husbandry practices. What is known is that they are largely deep water offshore schooling fish as adults, frequent flotsam as juveniles - this one probably came near shore riding along with vegetation - and there is a small market for them as a food fish overseas. Not a whole lot to go on. But so far it has adapted well, eats a large variety of foods, does like to hang out near structure, and is very active, as seen in the video.

video

So this small, dark, somewhat skittish but ever-wiggly fish is a mini-mystery. Just one of nearly 30,000 fish species from around the world; it has its place in the world but goes almost wholly unnoticed. I am professionally and personally interested in witnessing its growth and behavior and then releasing it back into the ocean where it belongs, to drift off once again into obscurity.