Blue Phantom Plecos L128 Hemiancistrus sp in the wild

By Ivan Mikolji / 2019

We turn on our small flashlights and start walking upstream on the Orinoco river bank. It is 4:30 am and I know that I am going to document one of the most spectacular places on earth. Maria, Alipio and I are carrying the heavy photo gear, we are huffing and puffing as we walk over a sandy stretch. The dry, soft river sand sinks with our weight making it harder to walk. They follow behind me as I choose the perfect spot to video and photograph the sunrise. It is hard to describe the magnificence of this place, it irradiates a powerful sense of history, but not a learnt history, but one that comes from deep inside you. I guess the best description I can come up with is: the place where the universe was born, where everything was created, where life started, you feel in the cosmogony. This incredible place is called the Atures Rapids and it’s the home of a very special fish, the still scientifically undescribed Blue Phantom Pleco, Hemiancistrus sp.

There are two predominant types of terrain here, sand and rock. These plutonic granite rocks are approximately 1,550 million years old and are sometimes referred to as Paraguaza rapakivi granite the locals call them laja (la-ha). Probably I should not be calling them rocks, I should be calling them large boulders because their size ranges from the size of a small car to the size of a basketball court. The speed of the water mixed with suspended mineral particles have water blasted the rocks for eons, smoothing them out until they look like dark chromed metal. In some spots the top of the boulders are covered in desert varnish making them even shinier.

After a long walk I find the perfect spot. We all sit and start setting up the gear. The strong deep rumble that the water makes as it flows down the rapids is always present. The Orinoco picks up speed as the rocky landscape narrows and shallows its flow. So many people have lost their lives, drowning in these strong white waters, the stories are abundant and the few that venture in the areas of strong current with their boats are respected and thought as the best captains.

We finish setting our gear and finally get a chance to sit down and enjoy. As we wait for the sunrise Maria and Alipio tell me how they fish the Blue Phantoms for the aquarium trade. They start by tying a long rope around Alipio’s waist, the other end of the rope is held by two other people. Maria then hands Alipio one end of a long seine fishing net and holds on to the other end. At that moment, Alipio jumps as far as he can into the rapids, holding the net as he is dragged downriver by the water current. Once the net is totally stretched out the two men pull Alipio out of the water 20 meters down river using the rope tied around his waist. Maria pulls the net out of the water at the same time as Alipio. The net drags over the smooth boulders catching the Blue Phantoms that live on them. Although the chosen fishing spots are not where the water current is strongest, if the rope breaks, Alipio would be dragged down river which would be extremely dangerous. There are some spots that have calm, slow water but they catch many more where the water is running. I guess the Blue Phantoms prefer more oxygenated and faster flowing water.

As the sun starts to rise, the morning sky turns blue which creates a strange visual phenomenon as the polished rocks reflect the blue sky and turn blue. At the same moment the banks of the river start filling with the song of thousands of birds that are awakening. Now it seems that you have a surround sound with the Orinoco River rumble on one side and bird songs on the other. We stand up and head upstream to a new location.

It is late February, the driest time of the year, and the waters are at their lowest level. In some spots the boulders and sand have lines which show how the water levels have dropped this year. In some places the water rises and lowers five or more meters! It is important to know that there are two ways of viewing an aquatic habitats climate, the hydrological periods and the climate periods. In this end of the Guiana Shield we have a bimodal climate regime consisting of a dry period and a rainy period. Curiously the river has a similar hydrological period but it is not exact with the climate periods, they do not align perfectly. For example, the Orinoco River water level in this area rises way before it starts raining. The locals say… “It’s raining down under.” Which means that it is raining down south in the headwaters of the Orinoco hundreds of kilometers away. Fish migrations and breeding behavior tend to be influenced by the falling or rising water hydrological periods while we still think that they are influenced by climate periods. It is really cool how once a year nature lowers the water levels in the river and allows us to see, walk and explore the Blue Phantom Pleco’s biotopes.

As I walk on the river edge I notice that the dry sand way up on the bank is much whiter, thinner, almost like a powder and it starts to gradually turn browner, darker and courser down the slope to the low river water level. The sand looks totally different than the dark chrome colored boulders.

We find a new spot with a nice view of the rapids. Maria tests the water and takes notes: pH 6.3, Temperature 27.3 °C. The only aquatic plants that we found are of the Podostemaceae family. These greenish yellow plants attach themselves to the boulders, near the water surface. You can only find them alive approximately from June to November when the Orinoco River water level stays the same for a couple on months. When the water level lowers again, they dry up under the scorching sun. The Orinoco River water in this area is not very clear, it has a light brown tinge and you can see things that are less than 10 cm deep from the outside. Underwater photographs taken in silty rivers do not come out that nice so we usually capture the fish and place them in a specimen aquarium with clear water. Specimen aquariums are very handy in these situations where the water current is too strong or dangerous. We also place a ruler in the specimen aquarium for future scientific reference.

There are two incredible things that make the Blue Phantom Plecos habitat even more special. The first one is that in some areas the chrome rocks are filled with some of the world’s largest rock art, also referred to as pre-columbian petroglyphs. These ancient, around 2000 year old man made markings become the habitat of the Blue Phantom Plecos in the rainy period, they live, feed and reproduce on them. The other incredible thing I found was a tree of the Myrtaceae family most likely of the Psidium genus. This tree, thought to be only terrestrial until now, is the only species of plant that survives below the mid water level of the Blue Phantoms biotope. This plant survives for up to eight months in total darkness, deep underwater when the water levels are high. Their trunks are black and smooth showing the same water blasted surface that the rocks show. Their trunks are also shaped by the direction of the strong continuous water current making them look like plants from another planet. Their roots curl around the smooth rocks which is the only way to keep them anchored and not being swept away. In the dry season when the plant is not submerged it shoots small green leaves out of its black stems. Sometime later it gives a small fruit which resembles a miniature, very sour guava. Most of these trees are covered in old fishing lines and hooks. Once the water levels rise, the cycle starts again, submerged in darkness, it loses its leaves and becomes part of the Blue Phantom Pleco’s home.

I start imagining an aquarium filled with large dark chromed rocks covered in ancient petroglyphs, thin ivory sand bottom, and a live, slanted, millenary looking bonsai guava tree with Blue Phantoms cleaning the whole thing when all of a sudden I step out of the trans and realize that Maria and Alipio are staring at me, I was daydreaming in Mikoljiland.

The Blue Phantom Plecos are thought to be a new species of catfish. Its closest known relative would be Hemiancistrus subviridis which seems like a yellowish-green version of the Blue Phantom Pleco. In the present we are collecting voucher specimens of the Blue Phantom Pleco for scientific study. Hopefully we will be able to know if it is a new species or just a color variant of Hemiancistrus subviridis.

We stay to photograph the magnificent sunset and watch the fishermen catch large Payaras in the strong water current. This place is magical…

This article has been published at:
  • Practical Fishkeeping Magazine (Opera of the Phantoms) July 2019