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Port Aransas fish kill caused by waterway cut off by low water levels

The drought and low tide are to blame for the fish kill
Port A fish kill.jpg
Posted at 6:07 PM, Jul 21, 2022
and last updated 2022-07-21 19:07:14-04

PORT ARANSAS, Texas — Earlier this week, officials in Port Aransas reported a fish kill to the Texas Parks & Wildlife Department. The fish kill was located in a canal that runs parallel to Seventh Street, between Avenue G and Avenue E.

Low tide and lack of rain combined to dry up the portion of the canal where it drains into the wetlands, cutting the rest of the water source off.

“The water is warming up, and when the water warms up, the oxygen starts to go down, the higher temperatures also mean the fish need more oxygen,” said Andrew Esbaugh, an associate professor of marine science at the UT Marine Science Institute. “So, they start sucking more oxygen out of the water, so it creates this hypoxic environment, and the fish essentially are on a clock.”

Alex Nuñez, the regional response coordinator for TPWS Kills and Spills, said it’s not uncommon to see fish kills like this in the area during the summer.

“In general, we get more fish kills in the summer time because it is a stressful time for the fish; water temperatures get high,” he said. “As water temperatures get high, they cannot maintain as much oxygen in the water, so we’ll have these small pocket areas where we’ll have these low dissolved oxygen fish kills.”

Nuñez said the drought played a role in this kill, but it could’ve happened in a year without a drought. Even if the area still went a long time without a drought.

“It really depends on the period between rain events,” he said.

However, there has been an increase in the number of fish kills reported this year.

“We are starting to get more calls of fish kills, the same species tend to be impacted. It begins with the smaller — people call them “Chads” or menhadens, in the one to two inch class,” Nuñez said. “This year, we seem to be getting a little bit more.”

This particular fish kill was not as severe as the one in the Nueces River earlier this month, but there have been more kills in areas where freshwater and saltwater sources meet.

“These areas, they tend to be naturally stressed environments, and that’s also the area where the menhaden tend to come in and feed,” Nuñez said. “So, a lot of our reports right now are in those tidal sections, and we’re getting a lot of those up and down the coast right now.”

It is possible the area will continue to see more fish kills, if we don’t get any rain in the forecast.

“Whenever you have these heat waves, warm temperatures, that’s going to cause the oxygen to get low, and that’s going to put more pressure on fish,” Esbaugh said.

However, Nuñez said it’s tough to predict how many more fish kills will happen, or how severe they will be, as there are several factors that contribute to a kill.