Heat and salinity kill off fish in Brac pond

| 16/07/2020 | 10 Comments
Cayman Brac
Dead fish at Westerly Ponds, Cayman Brac

(CNS): Hot, dry weather in Cayman Brac, which missed out on last weekend’s rain, and a rise in salinity at the Westerly Ponds seem to be behind the death of dozens of fish. Early investigations by the Department of Environment point to a significant fall in the water level at the ponds due to the lack of rain and an increase in salinity, compounded by a lack of discharge from the Brac Reef Resort’s wastewater treatment in the absence of visitors.

DoE Deputy Director Tim Austin said they believed the unfortunate fish were mullet (Mugil curema), which can tolerate fresh water as well as their natural environment of full strength sea water. But readings suggest the ponds were simply too salty and too hot.

“I think this is probably a natural cycle for the pond, but as the fish were trapped in there due to the low water levels, they couldn’t survive it,” Austin explained. “Ordinarily, these fish probably wouldn’t be in the pond but apparently they can enter through the drain culverts at the western end of the pond that connects to the sea.”

DoE Director Gina Ebanks-Petrie added that it was very likely that the fish reached the ponds through the sluice gates at the west end of the pond from the adjacent shallow lagoon. The gates were, it is believed, installed by public works some time ago to control water levels for the safety of the airport.

Having got into the ponds, the lower than normal water levels, hyper-saline water, high temperatures and low dissolved oxygen would all cause the fish to struggle, she added.

Residents told CNS about seeing dozens of dead fish, a phenomenon that many said they had never seen before at the ponds, though it is understood it has happened before. But it seems a combination of man-made changes to the landscape and rising heat, probably due to climate change, has compounded what were once far less deadly seasonal issues.


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Category: Marine Environment, Science & Nature

Comments (10)

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  1. Leigh says:

    If they had approved the opening of the pond to sea for a Marina, Hotel years ago this would be full of Live Fish. Unfortunately Politics stood in the way.

  2. Anonymous says:

    You should have see what happened to all of the snook, tilapia and lady fish in the spotts quarry when the East-west arterial was paved.

  3. Anonymous says:

    Not news, it’s happened many times through the years

  4. Anonymous says:

    It’s happened several times in years past. Not unusual

  5. Anonymous says:

    Got to love this hysterical pseudoscience… Yes, the fish are dead in scum pond “probably due to climate change”…. Seriously, this level of thinking is literally childish.

    Ponds dry up back and forth and this really really scary “phenomenon” has been occurring for millions of years in just about every part of the world. Anyone ever heard of the great salt lakes, for example in Salt Lake city Utah? Do you know there were once fish in there? And its evaporated all by itself long long before humans had cars, electricity and air conditioning.

    In fact there was water all through the mid areas and the great plains of the USA. That was all water and fish. Not anymore, and no aerosol cans where found in the fossil records.

    Critical thinking is dead.

  6. Anonymous says:

    Wait -Brac Reef was pumping its waste water into the western ponds?!? No wonder that whole area reeks.

    • Anonymous says:

      Treated waste water. The same as pumped into the ocean in GC by governors beach.

      • G says:

        Those pipes are relicts from when we used to abstract water from the ocean to perform RO and remove the salt for drinking water. The sand and grit wreaked havoc on our filters so we switched to ground water abstraction as the water gets naturally filtered by the limestone first.

        Unna need stop being CNS armchair experts and speaking on behalf of people who know a lot more than you on the subject. Treated waste water is discharged into very deep wells, far below where potable water is abstracted from. Fresh water floats above the brine layer sso there’s no mixing.

  7. Anonymous says:

    Always heard there is a waterway connected to the sea in the middle of the big tree in the pond there

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