First go the fish, then the people: the Zacate Creek fish kill

 

By Daniel Muñoa

 

During the last week of March, hundreds of dead fish were spotted along the banks of Zacate Creek in an area approximately five yards downstream of the Market Street Bridge . After hearing about the fish kill, I inspect the area myself, walking along a creek bed entirely of sandstone. The water flow has carved many channels as it makes its way to a sixteen-foot drop and gives rise to a sizable, cascading waterfall during periods of rain. I visited the area four times and encountered local residents more than willing to point me the way to the dead fish.

At a point approximately 100 feet downstream of the waterfall on Zacate Creek, I spotted a man fishing with a cast net. He was assisted by a teenager and three energetic young boys. The creek was still flowing from recent rains. I introduced myself as a biologist and asked the man if he had seen any dead fish in the area. He responded quickly in Spanish, "Aquí no hay pescados muertos." (There aren't any dead fish here). As he told me this, however, the three children indicated otherwise by pointing silently to a nearby area. I came across a bass more than a foot in length, dead and bloated floating on the surface of the water less than a hundred feet from where the man was fishing. In addition, there were a dozen four-inch carp that lay dead along the banks of Zacate creek. Upon seeing that I had spotted the dead fish, the fisherman called my attention to another area along the creek banks with more dead fish. At this point, there was little daylight left and I gave up the search and focused on the people around me.

I snapped a few pictures of the boys as they enthusiastically displayed the live carp the man had just fished out of Zacate Creek. I took the opportunity to inform them that they could be consuming fish containing toxic substances and that they shouldn't forget about the waste-water treatment plant that is nearby. Irritated, the man retorted, "Aqui no hay problemas," (There are no problems here), which his children also uttered in a drone-like chorus. Taking that into account, I said my good byes, grabbed my dog and made a hasty retreat to my truck, I crossed paths with a group of kids walking along the Zacate Creek Trail and asked if they had seen any dead fish. The children were quick to respond with information like, "Yesterday sir, I saw 200 dead fish." One girl told me to come back the following day during daytime to look around the banks of the creek immediately below the waterfall.

After several minutes of discussion, the children began to ask me what was going on, why the fish had died. I told them I didn't know, but at the same time, seized the moment to spread the good word of environmental stewardship. I discussed with them that the sudden deaths of so many fish could certainly be the result of toxic substances that were improperly disposed into storm drainages. Once released, these substances begin a long, poisonous and at times deadly passage through our creeks and eventually into the Rio Grande . The river in turn, spews its contents into the ocean, further spreading the contamination to a global level. I stressed to them that this is the kind of action that humans must stop, or else we will suffer from the negative consequences a degrading biosphere will have on living organisms. I also told the children that one possibility other than a toxic poisoning that could have caused the sudden death of these fish is a large sediment load from run-off. Sediment loads are known to occur in creeks during episodes of intense rain especially when there are many concreted culverts draining into a creek. Concrete drainages do an excellent job at conveying large amounts of soil and sediment from the drainages of our streets straight into to the Rio Grande because concrete is an impermeable material incapable of retaining any substance whether inert or toxic. The sediment chokes fish populations by keeping them from being able to extract oxygen from the water. This is one of the main reasons why it is better to leave creeks intact rather than destroying them with concrete liners that act as rapid conduits to the river. Natural riparian habitats are capable of filtering the water as it progresses towards the river by removing both sediment and toxic substances.

At this point, the kids seemed fairly distressed and asked how they could make a difference. I told them they should try talking to their parents about the situation and let them know how much it disturbs them to see dead fish in the creeks near their homes. In addition, they should ask their parents if the public officials they vote for care for the environment. I finished the conversation by saying that they can't simply think that local, state and/or federal agencies are working for our best interests in regards to safer, cleaner environment. More likely than not, and all too often we find that we elect public servants who don't have an environmental bone in their bodies. Nonetheless, since we live in a democracy, its our duty and right as private citizens and constituents of the Constitution to voice our opinion to try to ensure that elected officials follow the will of the people instead of the will of their own self interest.

I returned to Zacate Creek a day later to the spot that the girl had told me to look for the dead fish. Sure enough, there were hundreds of dead carp along with smaller numbers of catfish and bass. I took several photos, looked around and wondered what could have caused the kill. I became part of the process to determine what caused this tragic scene. It rained the day I planned to pick up water and soil samples, unfortunately flushing away any detectable amounts of toxins if present that could have been responsible for the dead fish. Dr. Tom Vaughan, a professor of biology at Texas A&M International University , visited the area and said that the entire bay area immediately below the waterfall was covered in suds of some kind, as if someone had dumped in large amounts of detergent.

I checked the creek twice more after that. The dead fish that were present the week before had been washed away by the torrents of March 29. I saw no signs of the suds Dr. Vaughan had observed earlier in the week and to my surprise, I observed hundreds of live fish and several turtles swimming in the bay area immediately below the waterfall. Small fish were jumping up against the falling water as some landed on the rocks nearby hastily flopping back and forth before making their way back into the water. There were several large groups of perch that swam round and round. It was a totally different sight from the one I had seen a week before and a very joyful one. At least not all hope is lost. in that life still thrives in these not so clean creeks of ours. It will be interesting to see in the coming days as the water level begins to drop if there will be any more dead fish present. If so, I plan to collect water samples, soil samples and specimens for analysis to try and shed some light on what may be killing the fish. According to the locals, this isn't the first time something like this has happened and from the looks of things it probably won't be the last. It is quite unfortunate that we are living in a world where more and more life is being sacrificed as a direct consequence of environmental degradation brought on by human activity.

 

How much more is it going to take to get the message out that we have to be mindful of how we treat the earth? Will it be another thousand or ten thousand living organisms that must perish before we change our ways? Or will it even take our very own existence to be threatened before people start to care more for the earth. By no means is the world going to end from one day to the next as a result of environmental degradation. However, there has been and continues to be a slow, worsening trend in the areas of global warming, the ozone hole over Antarctica and the Arctic region, the dramatic rise in carbon dioxide concentrations in the atmosphere, and more and more ozone alerts in large metropolitan areas to name a few problems. Left un-addressed, these problems could worsen over the next hundred years to the point that economies begin to fail resulting from dwindling natural resources. There is still time to curb the negative impact that we have had on this planet if we take the time out of our daily lives to become involved in environmental issues whether it be planting a tree in your front yard, or helping clean a creek. If you are interested on learning more about environmental issues, the internet is an excellent source of information so long as you check the credentials of the websites visited. Everyday I look into my one and a half year old niece's eyes and wonder what kind of world will she be living in twenty years from now? What kind of world will her children and her children's children live in if humanity continues to rape the earth?