TEXAS PARKS & WILDLIFE FISH KILL DATA SYNOPSIS / RECOMMENDATION
A recent fish kill on Lake Livingston was not made public information while another almost concurrent fish kill on Lake Bastrop was highly publicized. The Texas Parks & Wildlife Department (TPWD) claims that a press release informing the public on the Livingston kill "was not warranted". The much publicized Bastrop press release attributed the kill to the Large Mouth Bass Virus (LMBV) and was used to deliver the standard Public Relations message as follows. TPWD is right on top of fish kill events and the kills attributed to LMBV do not have a significant effect upon fishery productivity. Rayburn and Fork residents know that estimates of fish kill severity are grossly understated in TPWD press releases. Fish kill statistics within the state of Texas are discussed herein. It is apparent that TPWD is very reluctant to identify specific causes of fish kills that that could be used to identify sources of pollutants that have a negative effect upon our fisheries. A recommendation for a mandatory procedure is made that would put more focus on pollution issues and provide impetus for remedy.
TPWD posts fish kill data (Prism data base) on their web site that depicts the location of all known kill events as symbols overlayed upon a state map. The page is formatted to allow the user to select the calendar period of interest through the year 2000 and to also allow the user to select display of fish kills attributed to a various causes. There are some 16 causes that can be selected from their data base individually or collectively, to enable display of the locations of fish kill events that TPWD has attributed to the cause/s.
The available menu picks for fish kill causes consist of; "Disease, Inorganic Compounds, Low Dissolved Oxygen, Organic Compounds, Trauma or Physical Damage, Color/ Scum/Foam, Solid Wastes, Temperature, Other, None, Not Applicable, Unknown, Not Recorded, Bio Toxin, Pollutant, and finally, All".
Comparison of the displays of the "Prism" data depicting fish kill events as symbols on a map of the state in the years 1990 through 2000 leads to some interesting conclusions.
There were hundreds of fish kills in Texas in the 1990 to 2000 period when "All" causes are considered. (Actual numbers of kill events are not directly available from the on-line data presentation but is estimated by considering another source as well over 2000.)
The greatest kill event densities (number of kill events depicted per unit of map area) occur along the Gulf Coast and in the more heavily populated industrial / municipal centers and in East Texas forested / agricultural areas.
The TPWD data indicates inadequate dissolved oxygen is the most common cause of fish kills. The specific cause of inadequate dissolved oxygen is rarely identified or made public information by TPWD.
Organic and Inorganic compounds appear to be ranked 2nd & 3rd as causes of the displayed kill events.
The numbers of kill events TPWD attributes to Disease is very sparse in comparison to Organic Compounds, Inorganic Compounds, and Low Dissolved Oxygen causes.
In the period from 1990 to 2000 only 5 fish kills were attributed to "Pollutants" by TPWD. This is about onefourth of one percent of all fish kills.
In the period from 1990 to 1995 only one fish kill event of approximately 1600 was attributed to "Pollutants" by TPWD. That one must have been an irrefutable, no doubt about it event to earn a pollutant label from TPWD as a cause. .
Apparently the TPWDs data base managers definition of pollution is unique and is not the same as that defined in most dictionaries.
Another source of fish and wildlife kills data is in a paper presented to the American Lakes Management Society annual meeting in Houston in December 1997. The paper title is Thirty years of investigating Fish and Wildlife Kills and Pollution in Texas. This paper also provides TPWD conclusions pertaining to fish kills. Portions are excerpted from the TPWD web page as below.
Sixty percent of all fish & wildlife mortality in water was caused by low dissolved oxygen. The low dissolved oxygen was attributed to natural or unknown causes in only 19% of these events. Toxic spills, toxic algae, and other unknowns were identified as the causes of the remaining (49%) kill episodes. Apparently a miniscule number of these toxic spills causing fish mortality were considered to be Pollutants
According to this document; "About half of the incidents were Pollution Incidents and half were Fish Kills, along with fewer incidents involving Wildlife". Specifically, the document indicates 49.3 of the "incidences" were Pollution Complaints, 43.2 % were Fish Kills, 2.6% were "Fish and Wildlife Kills", and 4.4% were Wildlife Kills. These data were said to represent 4637 incidents in the period between 1958 and 1997. It is interesting to note that the numerical sum of fish and wild life kills percentages (50.2%) almost exactly matches the number of pollution complaint incidences (49.3%) identified in this document. The remaining 0.9% was classified "other". The document does not explicitly define incidence.
In stark contrast, the TPWD "Prism data" presented in the map displays discussed previously herein indicates that only five of approximately 2000 fish kill locations depicted were attributed to pollutants in the 1990 to 2000 calendar period and only one kill in over 1600 kills in the 1990 to 1995 period. The paucity of kills attributed to pollutants depicted in the map displays is incongruous to say the least. It is very likely a consequence of a desire to avert; focus, assignation of blame, legal contests, and the political influence of lobbyist interests.
Pollution "incidents" and fish kill episodes will not decline until a change in TPWD and other agency policy puts some focus on these events. The actions outlined below would be beneficial if they were made mandatory. The most significant difference in the recommendations listed below and TPWDs official Investigative Procedure is that the actions outlined below would be made mandatory. TPWD leaves most action decisions to the discretion of the investigative personnel (or their managers). The recommendations are:
Make public announcements via press releases of all fish kill episodes taking place within the state of Texas.
Inform all state agencies and federal agencies having interests in water quality within the state when a fish kill occurs.
Provide all TPWD fish kill investigative reports to the agencies having an interest in water quality within the state.
Make a formal request of state agencies to examine effluent discharge records and similar data in a water body which experiences a fish kill and to report conditions detrimental to aquatic life existing prior to the event to TPWD.
I challenge the reader to get a real definitive answer to this question. Is there a centralized location or office within the Texas Natural Resources Conservation Commission (TNRCC) with responsibility for maintaining a log or record of events such as inadvertent releases of contaminants to surface waters, wildlife kills, and fish kills that are reported to TNRCC by other state or federal agencies? TNRCC should recognize the value of fish kill records as evidence of integrated effects of water contamination.
It appears that TPWD does just enough investigation to find a plausible cause for a kill event and little more. The typical investigation results in attributing a kill to inadequate dissolved oxygen but rarely identifies the cause/s of inadequate oxygen. Correction of the causes of fish kills will be rare indeed as long as TPWD continues to conduct passive, non- aggressive investigations and fails to inform regulatory agencies and the public of the facts pertaining to significant fish kills. The TPWD fish kill data collection and records are of little value if they are not used to put focus on and remedy the problems affecting fish, wildlife, and recreational values within our state water bodies.
Walter West, P.E. / firstname.lastname@example.org
click below for new information from Walt West (8-22-02)
TEXAS FISHERIES ASSESSMENT HISTORY - Documented declines in population survey results contradict some agency claims.