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Why Manatees Need Protection
Reading Writing Selection

Although scientists counted a record number of manatees during the 2001 Statewide Synoptic Survey in Florida, there is no question that this endangered species still needs protection for many reasons.

1) Has There Really Been a Significant Increase in Manatee Population?

Save the Manatee Club scientists believe that the 2001 record high count of 3,276 manatees (637 more than the previous high count of 2,639 in 1996) was an irregularity. They state the record high count was simply the result of having ideal counting conditions, and is not a sign of a rising population.

Dr. Bruce Ackerman noted that "Counts can be highly variable due to weather conditions, and this year's [2001 record high] count isn't entirely unexpected", because of the perfect counting weather. Importantly, he added that even with the high count in 2001, scientists remain cautious about the overall manatee population.

While boating groups may say the 2001 record count shows a significant population increase, manatee scientists have strongly disagreed. In a March 1, 2002 Palm Beach Post article, Save the Manatee Club Biologist Patti Thompson indicated that "It is utterly irresponsible for them (boating groups) to say that manatees are thriving. The data are not complete enough yet to even say whether they're stable, much less climbing."

2) Do Endangered Species Need More Protection? Why?

The manatee is an endangered species, and the record high count in 2001 doesn't lessen the need to protect them. Dr. Ackerman pointed out that:

"Even 3,000 manatees is not that many individuals of an endangered species. It might seem like a lot more than 2,600, but it's not that much more.
[Because this is an endangered species]
It's like having your life savings being $3,000."

FFWCC024
Credit: FWC



When the entire population of a species is so small, it is placed at serious risk if a widespread disease comes along. Just a few years ago the manatees faced such a risk when they were exposed to red tide. In 1996 alone, red tide alone killed 151 manatees, and that didn't even count all the manatees that died from other causes that year!

Already this year too, scientists from the Florida Marine Research Institute suspect that 27 manatee carcasses brought in from four southwest counties between March 15 and April 16 died as a result of exposure to red tide. Samples collected during necropsy were sent for a toxicological analysis that shows whether the red tide toxin is present in an animalís urine, stomach, and liver.

A federally appointed advisory panel, The Working Group for Unusual Marine Mammal Mortality Events (WGUMMME), has declared this an unusual mortality event.

3) How fast is the rate of reproduction in this species?

Manatees have a very slow reproduction rate. According to Nancy Sadusky from Save The Manatee Club, scientists believe females do not become sexually mature until five years of age. Males are mature at approximately nine years of age. Once they are mature, manatees usually bear one calf -- twins are rare. Intervals between births range from two to five years, and the gestation period is approximately 13 months.

The very slow reproduction rate emphasizes that the death of any mature manatee can have a significant impact on the population.

It underscores how important it is to prevent deaths and injuries to the manatees.

FFWCC034
Credit: FWC


4) Will the death rate likely increase or decrease? From what causes?

The number of manatees that die each year in Florida has generally increased over the years. When scientists started counting in 1975, they recorded 29 manatee deaths that year, 6 of which were from boating causes. Last year, the 2001 count was 325 manatee deaths, with 81 coming from boating causes.


Boat Registration Graph
click to enlarge

manatee_USGS0001
Credit: USGS-Sirenia


Boating related deaths have followed right along with the increasing number of boats in Florida.

5) Do non-fatal injuries affect Manatee reproduction?

In addition to the growing number a manatees killed by boats each year, many more are hit by boats and survive, but often with horrific injuries. Scientists are just beginning to study what effect these injuries may have on the overall health of the Manatee population? One of the topics they will study is the question of whether injured manatees may not be reproducing successfully?

6) Are other species protected more than Manatees? Why?

Several manatee scientists have noted that manatees do not receive the same level of protections as other species, especially when the data shows that so many deaths are being caused by a single cause-- boating.

In a March 1, 2002 article in the Palm Beach Post, Greg Bossart, director of marine mammal research and conservation at Harbor Branch Oceanographic Institution, said that this level of human-caused death would not be tolerated for other species. "'If we were doing these same things to any dolphin species, I guarantee you there would be a public and government outcry from here to Washington,' Bossart said. 'Animals that have more appeal to our emotional needs or spiritual needs or whatever get more attention. They (manatees) didn't get a TV series.'"

FFWCC034
Credit: FWC

 


What if Manatees had gotten their own TV show, like Flipper?

One Out of Every Four!
In the same article, Save the Manatee Club biologist Patti Thompson said that people should be shocked. Approximately 25% of manatee deaths, that's one out of every four, are killed by boating, which she described as "something that was preventable just by being more careful." She commented that if there was a single thing causing 25% of human deaths, "don't you think we'd be pretty worried about that?"

 
Try This! Journaling Questions
Discuss the questions below, which all play a role in understanding how fragile the manatee population really is:
1) What is the size of the manatee population?
2) Should an "endangered" species deserve more protection?
3) What is the rate of reproduction in manatees?
4) Do you think the death rate will likely increase or decrease? From
what causes? Can deaths be reduced?
5) Can non-fatal injuries affect manatee reproduction?
6) Are other species protected more than manatees? Why?

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