Water: The Science Beneath the Surface

This post written by Mike Fannin, Manager, Life Support Systems

Life Support Systems?! What the heck does that department do?  From filtration to chemistry, this blog series is a behind the scenes look into the Zoo’s most mysterious department.

Part I: Koi Stream in the John P. McGovern Children’s Zoo

As anyone with a pond knows, the battle to keep things looking good is a never-ending one. Water can turn green overnight, making it difficult to see fish, and a thick carpet of slime can appear, seemingly out of nowhere. Both of these situations arise from some sort of imbalance in the pond, but the culprit is the same – algae.

There are tens of thousands of types of algae in natural aquatic systems. Mother Nature keeps them in check (just like all other species on the planet) as other organisms compete for resources, food and living space. Man-made water features are not as diverse as they are in nature, so there is little to no competitive pressure; in an outdoor pond, algae are often free to run wild.

This was the case with the newly renovated Koi Stream feature in the Children’s Zoo. The filtration system was upgraded, which made quick work of the single-celled algae that is able to turn clear water into pea soup, but hair algae is not so easily controlled – it is not suspended in the water like the single-celled varieties. If left unchecked, it grows on everything, trapping detritus (such as leaves and leftover food), slowing water flow and clogging filter intakes. In short, it can be an aquatic nightmare.

Algae in the koi stream.

So… what to do? There are a lot of chemicals that can be added to the water to kill algae, but none will permanently solve the problem. In fact, most will end up spawning even more problems! Here at the Houston Zoo, we prefer to work smarter and do things naturally; we needed to create more biological diversity in our aquatic habitat, and we decided that a great start was the addition of a teeny tiny invertebrate, the amphipod.

Amphipods are micro-crustaceans found in aquatic environments all over the world and vary widely in their habits. Some eat plants, others are scavengers, some are fierce predators, and some are even parasites. We needed a plant-eating species to tackle our algae issues, so with a few ampiphods donated by a Zoo volunteer, we began with a 600mL beaker of water with a sprig of aquatic plant and dead oak leaves to hide in. We offered these amphipods different types of algae found in various aquatic systems throughout the Zoo, but they didn’t seem to like any of it… we would have to try another species of ampiphod. Next, we collected a different species of amphipod from the Zoo’s Reflection Pool and offered them the same array of algae that we gave the first group – they didn’t seem to care for anything until we gave them hair algae from the Koi Stream, which they ate immediately.  We continued to offer Koi Stream algae over the next couple of weeks to make sure the novelty didn’t wear off.  Not only were the amphipods devouring the algae, they were growing and reproducing – SUCCESS!

Now that we had found the type of amphipod to address our algae situation, we needed a lot more of them. Three, twenty gallon amphipod breeding aquariums were set up in a secret location (not many amphipods get to have gorillas for neighbors!) We added sponge filters, submersible heaters, and plants, plus leaf litter to make their new home complete. Then, we divided our small colony between the three tanks and added a few dozen individuals from the Reflection Pool to supplement the population.  Once a week, we harvested hair algae from the Koi Stream to feed our new friends and within a few months, the population exploded into the thousands! Now we had the numbers to keep the Koi Stream algae under control, but we didn’t have the habitat to support this large population of hungry crustaceans… We couldn’t put them to work until they had a place to call home.

Amphipods can easily swim around to search for food, but the adults and young need small, confined spaces to hide in. Their preferences are dense aquatic plants (especially the roots) and leaf litter. Leaf litter wasn’t a good choice for us because it could interfere with our ability to keep the filtration system running smoothly. The Koi Stream has some natural hiding spots, but not enough for the number of amphipods we need to effectively control algae. And plants? Sometimes it’s difficult to establish plants in a koi system because koi love to eat plants!

We needed something that would support aquatic plant life while somehow keeping the plants away from the fish, that would also conform to the long narrow shape of our koi exhibit. “Floating islands,” which are planters that float on the water’s surface, allowing plant roots easy access to stream water were our best choice. Not only was this the answer to all the needs listed above, but the dense mesh that makes up the islands also provides ample habitat for our amphipods!

As mentioned before, nature is all about balance. Waste products generated by fish supply nutrients for plant life, and the more fish you have in a body of water, the more nutrients are available. By adding more plants to our koi system, we limit the nutrients available to algae since they are in direct competition with the plants for food. The plants (and floating islands themselves) will also create shade, which will help decrease algal growth, since the algae typically prefers direct sun. Adding voracious algae-eaters, our army of amphipods, will ensure that any hair algae that does manage to grow in the stream will be kept under control. The expected result will be a healthy, well-balanced exhibit with crystal clear water, using nothing but simple filtration and biodiversity.

Be sure and visit often to monitor our improvements to the Zoo’s outdoor aquatic systems – and stay tuned for floating planter updates and photos in our next blog entry, Children’s Zoo Koi Stream: Part II!

The beautification of the Koi Stream in the John P. McGovern Children’s Zoo is an ongoing team project between the Houston Zoo Water Quality department, Horticulture department and Children’s Zoo husbandry staff.

Saving a Critically Endangered Toad Species 7,300 Eggs at a Time

Written by Colin Thompson

While the Houston toad hasn’t been seen in the wild in Houston since 1973, the Houston Zoo currently houses about 400 of them. Every year, we use this captive assurance population to bolster the wild population in Bastrop County. In 2015 we released about 600,000 eggs and in 2016 we released over 775,000 eggs. During the 2017 breeding season, we hope to release even more! Moving those eggs from Houston to Bastrop is no simple task though. This year, we’re taking a closer look at the impact our transport practices could be having on the viability of the eggs after they’re released.

Houston toad eggs are very fragile, as they lack a hard or leathery shell like bird or reptile eggs. Instead, the eggs are suspended in a jelly which forms a long strand. Each female toad lays one egg strand per year, and each strand contains an average of 7,300 eggs, with larger strands reaching over 14,000! To make sure we are using the best possible methods to transport these large masses of eggs, we’re setting aside about 100 eggs from each egg strand to monitor as a “control group”. The “control” eggs stay at the Houston Zoo, while the rest of the strands are driven two and a half hours away to Bastrop County. When we arrive, we remove another 100 eggs from each strand before releasing the majority of the eggs into the wild. We then drive those 100 eggs back to Houston to observe alongside the control group. By doing this, we can see if the development of our eggs is being hindered by the journey to Bastrop County, allowing us to alter our methods for better viability.

So far, we’re finding that the transported eggs are developing at the same rate as the control eggs, which means our transportation methods are not having a negative impact. This is great news for Houston toads! Keep checking back for updates on this year’s Houston toad breeding project, and be sure to visit the Swap Shop and Reptile House to see this awesome native species in person!

Birthday Shenanigans

Written by Kimberly Sharkey

Our twin goat boys just turned 1!

Seamus and Finnegan are West African Pygmy goats that came to the Zoo at just two days old. They soon joined the rest of the herd, where they are now a guest favorite. The Children’s Zoo team decided to give them proper Irish names since their birthday was so close to St. Patrick’s Day.  On Sunday March 7th, we threw them a birthday party didn’t let the rain dampen the festivities. 

Zoo guests joined in on the celebration and sang them Happy Birthday while the boys enjoyed their cake and presents. One lucky girl that shares a birthday with the goats got a chance for a memorable moment and posed for birthday photos with them! The boys loved the attention and we look forward to celebrating many more birthdays with them in the future.  Stop by the John P. McGovern Children’s Zoo on your next visit to wish the boys a happy birthday! 

We’re Accepting Volunteer Applications!

Written by Shina Bharadwaja

Adult volunteer applications are open through March 31, 2017!

We are so appreciative of our Zoo Volunteers, who play an important role in nearly every department at the Zoo. Whether you are interested in volunteering with events, animal teams, horticulture, or even administration, there is something for everyone. Our volunteers utilize service shifts to positively impact the Houston Zoo’s conservation efforts, locally, and around the world. With diversity in mind, we know that everyone has something unique and important to contribute to our Zoo. Therefore, we strive to provide opportunities where strengths can be applied while serving an important cause.

As a new volunteer, there are many opportunities to personalize your service by choosing from an array of shifts, such as guest service, events, and assisting in the goat contact yard. As our volunteers gain experience, they’re able to take advantage of specialized training opportunities like animal handling, interpretive storytelling, and much more! Volunteers can also join one of our many important (volunteer-run) committees which help the development of programs and shaping of Zoo culture.

If the Houston Zoo sounds like the place for you, join our conservation efforts and become part of our family by applying to be a volunteer! 

Mosquito Magnet

Mosquitos are naturally attracted to standing water, which is commonly found in items like old tires. When the tire is filled with water, they come in and lay their eggs. Houston Zoo Keepers drain the water twice each week, remove the larvae, and feed it to insects in the Bug House. The water is then re-used to attract other mosquitos. This is an easy and inexpensive way to control mosquitos! Learn how you can make your own.

March’s Featured Zoo Members: The Darbonne Family

We love our Members. Their incredible support allows us to make a difference to animals both locally and all over the world. This month, we’re spotlighting a family of Zoo Members that deserve recognition. We’re thrilled to introduce you to March’s Featured Members: The Darbonne Family

We asked the Darbonne’s to share a few words about what being a Zoo Member means to them. Here’s what they had to say.

“The Houston Zoo is a family story for us: So many of our favorite memories of good times together involve the zoo. We became members in 2014 when I visited a first time in more than a dozen years. So much had changed—so much so that I wondered briefly (and ridiculously) if the zoo had moved. But the long pond at the entrance was/is still there and clearly had been for decades; the loving attention to its detail is unmistakable.

At the zoo, my brother, Jude, and I discovered that his son, Jackson, 5, is quite the presentation-maker. Last year, he adopted Liberty, the bald eagle who resides at the Children’s Zoo. We know her as Betsy (Ross), since, when I gave him the adoption certificate, I didn’t recall her name and quickly thought of a name of a female American revolutionary.

Jackson reminds us all on each zoo visit that he will be visiting Betsy; therefore, we should remember to take him to see her. At the display, he will tell anyone/everyone, “This is my eagle. She is a bald eagle. Her name is Betsy. I adopted her.” Just as seriously, he will move to the sign, point to it and say, “She got an X-ray.”

On another visit, he and Jude simultaneously placed old cell phones of mine into the recycling bin. (Jackson’s fell in first, so he won “the race.”) We had been reading about this at the gorilla exhibit on previous visits and Jackson was extremely excited to participate in the campaign.

We’ve also heard the rhino-keeper’s talk, where he learned that the boys are brothers and what “the sticks” are for. (The rhinos rub their horns on them.) At the elephant-keeper’s talk, we learned that they are trained to offer their feet for cleaning and inspection. And we have hundreds more memories than space here to recount them all.

We are thankful for the Houston Zoo for making positive impressions on Jackson—and on us too—about what we can do to protect and nurture our fellow inhabitants of Earth. We are proud to get to participate in its important work by sharing our support of our Houston Zoo. Our world is a better place because of the Houston Zoo.”

From all of us here at the Houston Zoo, we want to say thank you to the Darbonne’s and all of our Zoo Members. As a Houston Zoo Member, your support truly makes an impact on the growth of our Zoo and conservation efforts. THANKS!

Crab Trap Clean-Up 2017

By Heidi Garbe,  Colleen Cavanaugh, and Houston Zoo Volunteer Penny O’Neal

The Houston Zoo teamed up with the Galveston Bay Foundation and Texas Parks and Wildlife on February 18th to help pull abandoned crab traps from Galveston Bay waters. We pitched in at two locations:  Bolivar Peninsula (at Stingaree Restaurant) and Fort Anahuac Park. The event was a success with teens, staff, and adult volunteers from the Houston Zoo coming together at these locations. In total, over 300 traps were pulled from the bay and are no longer a threat to other animals.

The group at Bolivar began the day by pulling up several crab traps that had been in the water near Stingaree Restaurant. The traps had become encased with pounds of mollusks and the group had to be creative in saving these creatures before removing the traps.

Teens participating in our new Adventure Programs spearheaded the on-land clean-up around the shore at Fort Anahuac Park. The collected five bags of trash, six bags of recycling, and removed two old tires from the marsh. When boats came in with traps, they helped to smash them and put them in the front loader to be thrown in the dumpsters.

Community members also volunteered their time and their boats to bring in crab traps to be smashed and thrown away. This work is crucial to support healthy Galveston area waters and to remove abandoned traps that catch more than the intended crabs. Additionally, it helps to protect blue crab populations. By removing these traps from the water, it is estimated that we helped save over 5,000 blue crabs that would otherwise perish in these old traps.  The removal of crab traps is only allowed for a short period of time every year, so it’s important to make a massive effort when we can.

The Houston Zoo informally presented on plastic pollution and sustainable seafood, too. Several people stopped at our table to get more information on these issues and what they can do to help clean up the beach and save marine life from damaging fishing practices. In addition to educating the public and helping to clean up the bay, the beautiful weather and good company made the entire effort fun! Want to get involved, too? You can learn more about the crab trap removal program here.

Special thanks to Stingaree Restaurant for their support and delicious food, and to the Galveston Bay Foundation for coordinating our efforts at these two sites! Amazing things happen when we come together as a community.

*Photos courtesy of Gene Fissler, GBF, and our volunteers!


Houston Toad Breeding Season Begins

Written by Amie Bialo

Over in the Houston toad facility we certainly do get excited about Texas-sized things. After counting our egg strands from the 2016 breeding season, we found we had something big to celebrate. During week 6 of breeding, we had a pair of toads produce over 15,000 eggs. Collected from previous years, our data shows us that on average our females lay around 7,000 eggs per strand. In 2016 we had 12 females produce strands that contained more than 10,000 eggs. There are many variables that impact egg production, though – even the weather.


While 15,000 eggs certainly sounds like a lot, it’s important to consider why toads produce that many. The Houston toad is an r-strategist species when it comes to reproduction. What this means, in general, is that they produce a large number of offspring, but don’t put very much effort into caring for them. The offspring of r-strategist species are often small, and quick to mature, with a low percentage chance of survival, and this is definitely true of the Houston toad. To contrast, a species that uses a K reproductive strategy will generally have offspring that is larger in size, slow to mature, and their parents will put in a lot of care to help them survive (think elephants).

As the 2017 breeding season begins, our hopes are high that we’ll see many large egg strands. Ideally, we hope we can combine the toads’ r-strategy with the extra care of our keepers and partners who help release the strands in the wild, and let the toads see some of the benefit of K-strategy leading toward higher offspring survival numbers than they would see alone in the wild.

What a Cute… Watermelon?

Written by Memory Mays

We’ve got a new cute addition to our Hoofed Stock Department at the Houston Zoo. This is Antonio, a baby Baird’s tapir.

After a 13 month gestation period, our female Baird’s tapir “Moli” experienced a short labor before birthing our newest baby male tapir. The calf was quickly on his feet and walking only about 20 minutes after being born! At birth he weighed 20 pounds and has been gaining weight over this past week at a normal growth rate.

You may notice the calf has a different coat color than his mother. Tapir calves are known for this coat pattern where the white stripes and spots covering their bodies resemble the stripes of a watermelon. This coloration helps the calves camouflage into the bushes and shrubs of the forests in Central America. These markings will slowly fade into the adult coloration after about a year.

With only about 5,500 Baird’s tapirs left in the wild, this birth is very important to help save this endangered species. On your next visit to the Houston Zoo, make sure to stop by our Tapir yard to see this amazing Baird’s tapir!

Pen Pals to Save Okapis: Conservation in the Ituri Forest

Written by Mary Fields

Last time we were in contact with our pen pal, Jean Paul, he told us all about what he does to help okapis in the wild. This time, he told us about the Okapi Wildlife Reserve and how it helps with conservation!

So what is the Okapi Wildlife Reserve? It is a world heritage site located in the Democratic Republic of the Congo that helps protect the Ituri Forest and its inhabitants. The Ituri Forest is one of the last reservoirs for biodiversity in Africa and a refuge for okapis, chimpanzees and forest elephants.

It is not just plants and animals that the OWR helps preserve; they help preserve the lifestyle of the indigenous people living in the forest. The Ituri Forest is home to the hunter-gatherer and deep forest-dwelling Mbuti and Efe pygmies.

The OWR focuses on working with the communities within and surrounding its boundaries. They provide zones for hunting, agriculture and full conservation. They also provide outreach programs for the public, schools and the government to help educate them on the importance of conservation and the reserve.

So how can you help okapis in the wild? By recycling your cell phones and electronics! You can recycle your cell phones at the Houston Zoo’s entrance and the African Forest. Make sure to follow our blog to continue learning about okapi conservation and hear more from Jean Paul!

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Don't miss this great event!Spring is coming, and so is Houston’s rainy season! This year you could save $$$ and protect the health our Bay by using a rain barrel! Go to galvbay.org/hzrbw and sign up to attend our Houston Zoo Rain Barrel Workshop (sponsored by LyondellBasell) on Saturday, April 8th! ... See MoreSee Less


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