Manatees Survive

2023 was the best year in two years for Manatees, but we can do better

Photo by Ray Aucott on Unsplash

Photo by The Tampa Bay Estuary Program on Unsplash

Manatees are under threat of extinction, and largely due to starvation from destruction of their habitat.

I wrote about the plight of the Manatees a little over a year ago, and I want to share that article from the closed archives with you.

There is a bit of good news after the manatees had a terrible year in Florida enduring Red Tide. Red Tide is an overgrowth of algae of which there are several that turn the water red. Karenia brevis, the red tide organism. produces a neurotoxin, brevetoxin, that causes neurological damage. It causes death to manatees when they ingest the neurotoxin that is present in the seagrass that they eat or inhale it.¹

The Florida Fish & Wildlife Conservation Commission provided these preliminary data on the mortality rates of manatees in this table, above.² The total for 2023 so far is 456 and looks like it will be an improvement over 2022 at 288 and the all time high number of deaths in 2021 at 941 deaths. However, the deaths from watercraft are still disturbingly increasing over 2022. Deaths by watercraft are the highest cause of death and rapidly increasing for the Antilles Manatee in Belize.³

Florida keeps data as far back as 1974 which you can review.⁴

The Manatee is protected by the Marine Mammal Protection Act of 1972, the Endangered Species Act of 1973, and state law, the Florida Manatee Sanctuary Act of 1978.⁵ Unfortunately, in 2017 the manatee was downgraded for protection on the Endangered Species List from “endangered” to “threatened”. This is inconceivable as a scientific matter when seagrass was destroyed which is their only food supply. (I was unaware that drunk-boat-driver-industry had such a strong lobby in Florida.)⁶ However, even threatened status requires a habitat recovery plan, and that is what is most needed as a matter that can be managed. (Red tide is an Act of God; and drunk boat drivers apparently have a good lobbyist but could be controlled with stricter enforcement of drunk driving laws on the water.)

The “sports” boating industry could improve its image by launching a campaign to watch and avoid manatees and maybe reward counties in Florida that have the lowest number of boat encounters that injure or kill Manatees. To avoid the unintended consequences of underreporting to gain rewards by counties, reporting would have to come from the state Fish & Wildlife Conservation Commission, rather than the counties self-reports.

Manatee in the water looking at speeding boats with seagrass in the water

So sensible regulation should be based on real constraints that are relevant to reducing manatee lethality. Florida reports about 100 manatees die each year from boat collisions.⁷ Fortunately, a Master’s degree student in oceanography (with a concentration in marine resource assessment) did a useful study that could be instrumental in meaningful regulation. First, looking at self-reported boat collisions and mortality, she found that there were a total of 149 encounters: 22 of those were known to be lethal; 8 were suspected; and the balance (119) were injuries with unknown outcome (some recover, some die). Then she correlated these collisions incidents with the speed the boat was going at the time of the collision. This analysis provides an excellent standard for speed that would reduce manatee deaths to near zero. ⁸

Note, the part of the graph depicting the increase in mortality which correlates positively with boat speed? That is, the faster the boat the more probable the death of the manatee. The second graph notes where the change in mortality is the greatest where the speed changes. So from 10 to 20 knots lethality increases rapidly; so the regulation should require boats to go not faster than 10 knots (or no more than 15 knots if it is not possible to set it at 10 knots) in any known manatee area. Ten knots would reduce mortality to almost zero, while 15 knots would reduce it by 50%. (A risk management or political choice.)

The Florida Miami-Dade County Manatee Management Plan in 2009 questioned what slow speed was actually best, and this Master's thesis has answered their question. The Miami-Dade County has the highest number of collision deaths of any other county in Florida.

State regulation

The state regulation to protect manatees mirrors that of the federal statute.

“it is unlawful for any person at any time, by any means, or in any manner intentionally or negligently to annoy, molest, harass, or disturb or attempt to molest, harass, or disturb any manatee; injure or harm or attempt to injure or harm any manatee; capture or collect or attempt to capture or collect any manatee; pursue, hunt, wound, or kill or attempt to pursue, hunt, wound, or kill any manatee; or possess, literally or constructively, any manatee or any part of any manatee.”⁹

There was at least one case filed in federal district court in Orlando, Florida against two men who were jumping on top of manatees including a nursing mother and her calf and posting the criminal act on Facebook, in 2012. This criminal case was filed under the Endangered Species Act and the Florida Manatee Protection Sanctuary Act. Taylor Blake Martin and Seth Andrew Stephenson were each sentenced to 175 hours of community service, and a $3000 and $2000 fine (respectively), 2 years probation and were ordered to post an apology on Facebook.¹⁰¹¹

The same statute also provides for the state commission to set boating speeds and to send that standard to the counties for review and adoption.¹²

The signage requirement is not a specific speed, but :

(b) “Slow Speed” and “Slow Speed Minimum Wake” . . . ¹³

So no specific speeds, but as we have learned by consulting studies on the correlation of speed with mortality —it should say speeds must be 10 knots or less.

But one improvement has been the required boat education course now includes information about manatees and other wildlife, in 2022.¹⁴

Further research is needed to see just how many boat drivers are penalized for collisions with manatees and whether repeated offenses make any difference, under local and state law.

Under federal law, in 2011, there was a rare prosecution of a boat operator who killed a nursing manatee with a baby going at a high speed, failed to report, but was reported by an eye witness. His penalty was to forfeit his $6,000 boat and contribute to a wildlife organization, but escaped what could have been up to one year in jail. He had been ticketed twice just prior to this fatal incident.¹⁵

Conclusion

Manatees have been around for 1.5 million years, and they have survived some incredible earth transitions. They deserve our respect and honor. However, for those who are unable to do that, there is the penal system, a necessary although poor substitute for respecting wildlife.

If humans could use their bigger brains and opposable thumbs to protect them or at least not kill them and their habitat, it would be a major win for the world. Using our scientific research to promulgate better regulations that are sufficiently narrow and optimally effective in reducing up to one half of all manatee deaths reportedly caused by boat collisions, that would be an admirable goal.

1. https://ocean.si.edu/ocean-life/plants-algae/what-exactly-red-tide

2. https://myfwc.com/media/30691/preliminary.pdf

3. https://news.ucsc.edu/2023/06/belize-manatees.html

4. https://myfwc.com/research/manatee/rescue-mortality-response/statistics/mortality/yearly/

5. https://myfwc.com/conservation/you-conserve/wildlife/manatee

6. https://news.miami.edu/stories/2022/02/no-longer-endangered,-manatees-now-face-another-crisis.html

7. https://wusfnews.wusf.usf.edu/environment/2022-12-01/floridas-boating-test-gets-an-update-with-questions-on-manatee-and-sea-turtle-safety

8. https://core.ac.uk/download/pdf/216960225.pdf

9. http://www.leg.state.fl.us/statutes/index.cfm?App_mode=Display_Statute&URL=0300-0399/0379/Sections/0379.2431.html.

10. https://www.justice.gov/usao-mdfl/pr/two-men-sentenced-harassing-manatees

11. https://www.news-press.com/story/news/crime/2014/06/18/two-men-sentenced-for-harassing-manatees/10799423/

12. Same statue, para. (f)

13. https://myfwc.com/media/13261/68d-23.pdf

14. https://myfwc.com/media/30424/6d-2-rl-68d-36.pdf

15. https://www.soundingsonline.com/news/plea-deal-costs-manatee-killer-his-boat