University of Puerto Rico, Rio Piedras Campus. Environmental Science Department. Coastal Environment Course.

1. The Speckled Caiman in Puerto Rico:
Assessing abundances and densities
of an unstudied invasive species.
J. Aaron Hogan
Michael Marty
Xiucheng Zeng
Department of Environmental Science, University of Puerto - Rico
Río Piedras

2. Contents
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Introduction
Goals & Objects
Hypotheses
Methodologies
References

3. Introduction
The Speckled Caiman
(Caiman crocodilus)
was introduced to the
coastal ecosystems of
Puerto Rico in the
1960’s.
Figure 1. Distribution of Caiman crocodilus.
Populations in Florida (USA), Puerto Rico and
Cuba are introduced.—by Velasco, A. and
Ayarzagüena, J. (2010).

4. Are they far away from us?
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Caiman was sighted in at least 18 watershed localities of San Juan.
1) Laguna San José;
2) Quebrada Juan Méndez;
3) Canal Blasina;
4) Sector Bechara in Avenida Kennedy;
5) Caño Martín Peña;
6) Islote Juan Pérez in Piñones;
7) Piñones;
8) Canal Vista Mar;
9) Canal Flamboyanes;
10) Borinquen Towers;
11) Río Bayamón in Bayamón;
12) Vertedero in Carolina;
13) several other localities in Carolina;
14) Urb. Villamar in Isla Verde;
15) Ave. Roosevelt in Puerto Nuevo;
16) Ciudad Deportiva Roberto Clemente;
17) San Francisco in Río Piedras; and
18) Base Muñiz in Carolina
Figure 2. San Juan Bay Estuary.

5. Why should we care?
• Caimans have been reported to:
– Prey on numerous vertebrates and
invertebrates species.
– Be aggressive and dangerous to humans.
– Serve as vector of foreign pathogens and
diseases.

6. What do we already know about caiman?
• Let us build on J. Bauza R. Joglar
• WHY NOT
• What is more?
ET
L
S
U
FIND OUT!!!!

7. Goals & Hypotheses
• Objective 1: The primary objective of this study is to
document the extent of the introduced caiman population
on the main island of Puerto Rico. ( Such as size, age
and sex structure of the caiman population). This data
can be use for further research of caiman in Puerto Rico.
• Hypothesis 1: We hypothesize that areas with closer
proximity to the point of introduction (Laguna Tortugero,
Manati, Puerto Rico) will have higher overall abundance
and densities of specked caimans. In other words, areas
further west in the SJBE will have more caimans.

8. Goals & Hypotheses
• Objective 2: Find out the
relationship between
Caiman habitat with
urbanization, water
quality.
• Hypothesis 2: We predict
that the speckled caiman
will be more abundant in
disturbed areas. We also
hypothesize that sites
with poorer water quality
will support more
abundant caiman
populations.
Caiman
habitat
Urbanization
Water
quality
Urbanization
Water quality
Figure 3. Relationship illustration

9. Goals & Hypotheses
• Objective 3: Collect a
sub sample of caimans
found throughout the
estuary to investigate a
number of parameters.
Phylogenetic barcoding to verify
species, caiman health
and disease
prevalence, stomach
content analysis.
• Hypothesis 3: We will
find caimans.
Figure 4. Different species of Caiman
http://dinets.info/crocs7.htm

10. Methodologies
• Population quantity investigate
– Spotlight boat surveys
• Conduct a series of pre-planned nightly spotlight
observations.
• WE WANT TO SEE CAIMANS. WE WILL COUNT
THEM AND COLLECT DATA
– Body form observation
• We will approach caimans and estimate their total
length, tail length, header size, gender, etc,. The
size records will be divided into 4 categories and
use to speculate their age

11. Methodologies
• Species identification
– Census counts
• We will document caimans and identify them to the
best of our ability.
• Population Viability Analysis (PVA)
– Sample collection & Genetic analysis
• We propose to collect a subsample of 50 caimans.
• We will collection some tissue in order to identify
genetic diversity. PHYLOGENTIC
IDENTIFICATION.
• American crocodiles are speculated to be living in
PR.

12. Methodologies
• Water quality assessment
– We will link water quality data from
estuario.org (SJBE program)
• SJBE program has an extensive of water quality
dataset.
• Scientific obligation
– Link GIS land cover urbanization data
• Extent of urbanization data are available. We
would like integrate into ULTRA (if possible)
Otherwise community involvement is our focus!
• Many projects and offer an great opportunity for
citizens to integrate into the environment.

13. Methodologies
• Urbanization
– BIG TICKET IN PUERTO RICO
• High population densities
– WHAT IS URBAN ECOLOGY?
• ALONZO RAMIREZ
• Biotic homogenization
– URBAN CAIMAN ECOLOGY

14. INTEGRATION

15. Student Involvement
• THIS IS EVERYTHING! Por que no?
– Opportunities for research and resume
building
• We seek to employ anyone and everyone
who is willing to volunteer.
• Experience la naturaleza at night. Why
not count caimans…

16. THANK YOU!!

17. Refences
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Ayarzagüena, J. (1984). Ecología del caimán de anteojos (Caiman crocodilus L.) en los Llanos de Apure (Venezuela).
Doñana Acta Vert. 10(3): Seville, Spain
Bayliss, P., (1987 Survey methods and monitoring within crocodile management programmes. In: Webb, G.J.W., Manolis,
S.C., Whitehead, P.J. (Eds.), Wildlife management: Crocidiles and Alligators: Surrey Beatty and Sons, Sydney, Australia,
pp. 157 - 175.
Da Silveira, R., Magnusson, W. and Campos, Z. (1997). Monitoring and distribution, abundance and breeding areas of
Caiman crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil. J. Herpetol. 31(4):
514-520.
Da Silveira, R., Magnusson, W. and Thorbjarnarson, J. (2008). Factors affecting the number of caiman seen during
spotlight surveys in Mamirauá Reserve, Brazilian Amazonia. Copeia 2008(2): 425-430.
Joglar, R. RAPID ASSESMENT
Read, Mark A., et al. "The distribution and abundance of the estuarine crocodile, Crocodylus porosus, in
Queensland." Wildlife Research 31.5 (2005): 527-534.
Thorbjarnarson, J.B. (1993). Fishing behavior of spectacled caiman in the Venezuelan Llanos. Copeia 1993: 1166-1171.
Thorbjarnarson, J.B. (1994). Reproductive ecology of the spectacled caiman (Caiman crocodilus) in the Venezuelan llanos.
Copeia 1994(4): 907-919.
Tucker, Anton D., et al. (2007) "Growth dynamics of freshwater crocodiles (Crocodylus johnstoni) in the Lynd River,
Queensland." Australian journal of zoology 54.6: 409-415.
Tucker, A. D., et al. "Movements and home ranges of Crocodylus johnstoni in the Lynd River, Queensland." Wildlife
Research 24.4 (1997): 379-396.
Velasco, Alvaro, and José Ayarzagüena. (2010) "Spectacled caiman Caiman crocodilus." : 10-15.
Webb, G. J. W., S. C. Manolis, and R. Buckworth. (1983) "Crocodylus johnstoni in the McKinlay River Area N. T, III.*
Growth, Movement and the Population Age Structure." Wildlife Research 10.2: 383-401.