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Manatee Conservation

Emily Drown, Marisa Brendel, Sierra Kopp & Autumn Ruleau

Principles of Ecology

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Introduction

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  • The manatee is a large marine mammal that has an egg shaped head, a wide, paddle-shaped tail and two flippers.
  • Officially considered an endangered species on March 11, 1967.
  • No natural predators
    • Alligators, sharks
    • Watercraft collisions
  • 2001 Florida Manatee Recovery Plan

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“Sea Cow”

Trichechus manatus

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Introduction

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  • This study was conducted in manatee protection zones (year-round and seasonally) in Florida, USA. (rivers, bays, canals, costal areas)�
  • Manatee samples were collected using satellite-linked radio-tags between the years of 1991 to 2018. �
  • All samples were collected during cool weather, following a prolonged period of cold weather, with low winds and bright sunshine.

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Methods

  • Satellite-linked radio-tags are used to study the movement and habitat use of manatees.�
  • The floating tag contains a GPS unit, a satellite transmitter, and a VHF transmitter. �
  • The GPS unit can be programmed to locate the manatee at any time interval that provide information on manatee movements and habitat use.

Florida Fish and Wildlife Commission

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Methods

Protected zone-

-Manatee Management Plan (2007)

-Various protection programs � �

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Slow speed zones

Restoration and �enhancement of habitat

Restricted Zones

Florida Fish and Wildlife Commission

FWC

FWC

FWC

Online Fisherman.com

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Hypotheses and Research Questions

  • H1: Manatee counts in protected zones have not changed with protection laws.
  • H2: No difference exists between the mean number of manatees in protected counties from before and after 2007.
  • H3: No difference exists between manatee counts in non-protected zones from 1991-present.
  • H4: No difference exists between seasonal and year round protection zones.

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Results: Hypothesis 1

H0: Manatee counts in protected zones have not changed with protection laws

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-Manatee protection laws put in place beginning in 1991

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-Regression Analysis: Shows highly significant

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-Evidence to reject the null

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-Mainly linear except for a few peaks

-(Brevard County) due to Florida Power & Light� Co. power plant

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d.f=16, F=2.09814E-05, p-value=<0.001

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Coastal News Today, 2016

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Results: Hypothesis 2

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H0: There is no difference between the mean number of manatees in protected counties from before and after 2007.

Two-tailed t-test

p-value= 0.2277

Standard error before 2007= 59.87002

Standard error after 2007= 118.1487

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Results: Hypothesis 3

  • Ho: No difference exists between manatee counts in non-protected zones from 1991-present

-Regression Analysis: shows highly significant

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-Evidence to reject the null

Regression Analysis, p-value <.001, d.f =13

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Results: Hypothesis 4

H0: No difference exists between seasonal and year round protection zones

Two sample t-test, d.f.= 389, p-value= <.001

-Does not necessarily mean year round protected areas are not more effective

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-Some seasonally protected zones simply have much larger manatee counts (Brevard County)

Palm Beach Post

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Discussion

  • Regression analysis
    • Manatee counts in protected areas show a statistically significant increase since protection laws were enacted
    • Manatee counts in non-protected areas show a statistically significant decrease since 1991 �
  • Two sample t-test
    • Seasonally protected zones have higher manatee count
      • Due to power plant in Brevard County

- Mean number of manatees before and after 2007 not statistically � significant, but meaningful for manatee population numbers

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Conclusion

  • Are the Florida protection zones helping manatee populations?
  • YES
  • Likely because of restrictions on watercraft
  • Reclassified as “threatened” in 2016

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Conclusion

-Estimated 1,267 manatees in FL in 1991

- 6300+ manatees in FL today

-Significant increase over the past 25 years.

-Removed from the endangered species list, now threatened

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References

http://myfwc.com/wildlifehabitats/managed/manatee/data-and-maps/

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  • Florida Fish and Wildlife Commission, Division of Habitat and Species Conservation Imperiled Species Management Section

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http://f50006a.eos-intl.net/ELIBSQL12_F50006A_Documents/Manatees.pdf

  • Sea Stats: Manatees, Florida’s Gentle Giants

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Questions?