PROTOCOL FOR CLOSING AND REOPENING
RIVERS AFFECTED BY PFIESTERIA OR
PFIESTERIA-LIKE EVENTS SUMMARY

A CLOSURE WILL BE RECOMMENDED WHEN: A significant fish kill in progress is confirmed and the affected fish are exhibiting Pfiesteria or Pfiesteria-like sores; OR

A significant number of fish are confirmed to be acting erratically (and no other explanation for the behavior is apparent - ex. low dissolved oxygen) or 20% or more of one species (from a minimum of 50 fish of the species collected) are exhibiting fresh Pfiesteria or Pfiesteria-like sores or there is evidence of increased Pfiesteria or Pfiesteria-like activity, as reflected by an increase in the number of fish with Pfiesteria or Pfiesteria-like lesions.

A REOPENING WILL BE RECOMMENDED WHEN: The conditions that initiated the closure have ceased for 14 days.

PROTOCOL FOR CLOSING AND REOPENING RIVERS
AFFECTED BY PFIESTERIA OR PFIESTERIA-LIKE EVENTS


Detailed Procedures:

A closure will be recommended when:

  • A significant fish kill in progress is confirmed and the affected fish are exhibiting Pfiesteria or Pfiesteria-like sores; OR

  • A significant number of fish are confirmed to be acting erratically (and no other explanation for the behavior is apparent - ex. low dissolved oxygen) or 20% or more of one species (from a minimum of 50 fish of the species collected) are exhibiting fresh Pfiesteria or Pfiesteria-like sores or there is evidence of increased Pfiesteria or Pfiesteria-like activity, as reflected by an increase in the number of fish with Pfiesteria or Pfiesteria-like lesions.

Procedures:

  • Based on one of the above conditions, the Department of Natural Resources (DNR) Secretary will recommend closure of the affected area to the Department of Health and Mental Hygiene (DHMH) Secretary who will consult with and coordinate closure implementation with local health officials.
  • Closure boundaries will be determined through visual observations and review of fish caught using cast nets and/or trawling the river. Closure areas will be actively monitored and assessed for fish health and Pfiesteria or Pfiesteria-like activity.
  • Notification of river closures will be posted to protect the public from possible health complications which may result from direct water contact while the toxin is active.

Reopening will be recommended when:

  • The conditions that initiated the closure have ceased for 14 days or tests for toxic Pfiesteria or Pfiesteria-like organisms are negative.

Procedure:

  • The DNR Secretary will recommend reopening to the DHMH Secretary, who will consult with and coordinate reopening with local health officials.

A temporary advisory will be issued when:

  • A significant fish kill in progress is confirmed, the fish do not exhibit Pfiesteria or Pfiesteria-like sores, and no other explanation for the kill is apparent (ex. low dissolved oxygen).

Procedure:

  • A preliminary water analysis for toxic Pfiesteria or Pfiesteria-like organisms will be done to rule out Pfiesteria or Pfiesteria-like organisms as a cause of the kill.
  • If the preliminary results demonstrate that the cause IS Pfiesteria or Pfiesteria-like organisms, the DNR Secretary will recommend to the DHMH Secretary that the advisory be changed to a closure.
  • If the preliminary results show that Pfiesteria or Pfiesteria-like organisms are NOT the cause, the DNR Secretary will recommend to the DHMH Secretary that the advisory be removed.

Comments:

  • Current scientific knowledge indicates that toxins emitted by Pfiesteria and Pfiesteria-like organisms break down in less than 48 hours. However, much work is ongoing to identify the nature and activity of the toxins. This protocol may be modified if warranted in light of improvements to our knowledge.
  • Current scientific knowledge also indicates that the behavior of Pfiesteria and Pfiesteria-like organisms is seasonal and episodic in nature. Therefore, closure and reopenings may be repeated as necessary.
  • This protocol is based on evolving scientific knowledge and experience with Pfiesteria and Pfiesteria-like organisms and is subject to continuous evaluation.
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