Study on the population status of the yacaré (Caiman yacare) and the black caiman (Melanosuchus niger) in their natural distribution areas in Bolivia

Aug 31, 2021Bioamazon Project, News

Authors: Fundación para el Desarrollo de la Ecología FUND-ECO

Contact: jehaninon.rios@gmail.com

The National Program for the Conservation and Sustainable Use of the Yacaré (Caiman yacare) – PNCASL (for its acronym in Spanish) was originated in Bolivia, from the Supreme Decree No. 24774 promulgation, in 1997. This Decree approved the first Regulation for the Conservation and Exploitation of the yacaré, in the face of a series of failed protecting measures of Bolivian biodiversity, which was exposed to the intense exploitation (S.D.  21312), and from an Indefinite General Ban imposed at the national level in 1990 (D.S.  22641) for the chase, capture, storage, and conditioning of wild animals, as well as the collection of wild plants, and their derived products.

The main objective of the yacaré harvesting process is to guarantee the biological, economic, and social sustainability of the Caiman yacare in Bolivia, ensuring a fair and equitable distribution of benefits.  For this purpose, the main biological criteria provided, which were taken from the Venezuelan model for commercial exploitation of (Caiman crocodilus), are:

  1. The yacaré harvest model is based on hunting adult male individuals with a total length (snout – tail) greater than 180 cm (Class IV), coming from wild populations in the natural range.
  2. The harvest is based on the population abundance and structure, authorizing a maximum of 25% of Class IV individuals, provided that they exceed 15% of the total population, without considering the animals from the first year (Class I).
  3. Annually, the populations of the Caiman yacare must be evaluated by night counts within the whole range.

The consultancy aimed at preparing the study of the population status of the yacaré (Caiman yacare) and the black caiman (Melanosuchus niger) in their natural range, in Bolivia, within the framework of the Bioamazon Project – Conservation of species threatened by unsustainable trade, started in March 2020. Due to the pandemic caused by SARS-COV-2, the study was paused, and therefore, it had to be extended until October 2021.

The main objective of the consultancy is to conduct populational studies about the yacaré (Caiman yacare) and the black caiman (Melanosuchus niger) in their natural range in Bolivia, and to plan models and criteria to estimate their populations susceptible to harvesting This study is a very important yacaré resource management tool, with which the Competent Environmental Authority can guarantee its sustainable use, considering that the latest estimated quota calculation model for the potential harvesting of this species, in the provisions PNCASL authorized, is from 2010.

Photo: Jehan Ninon Rios-Rios

To date, the activities that have been developed within the framework of the execution of the consultancy are the following:

  • Review of the state of the art on the knowledge regarding the biology and natural history of the black caiman in the country, in order to serve as a basis for identifying populations prone for exploitation and to determine basic biological criteria for the management of their populations. Most of the published and unpublished information on these species corresponds to the survey of population parameters (abundance and structure), however, there is a lack of studies on reproductive biology, habitat use, genetic structure of populations and ecology, which is a very important data for the management of their populations.
  • A single Database has been consolidated with information from different sources generated in the last ten years related to population parameters of yacaré under management and populations of black caiman. This information was scattered, and the need to establish information standardization criteria within the Competent Environmental Authority was observed, both for data collection and for its analysis and the adoption of methods for defining harvest quotas.
  • Population evaluations have been carried out in two indigenous territories in the department of Beni: the Indigenous Territory and Isiboro Sécure National Park (TIPNIS) and the Chimán Indigenous Territory (TICH), characterizing the populations of yacare and black caiman and conducting interviews on the perception of the hunters and beneficiary families about their degree of empathy for these species and the benefits of harvesting these species at the family and community level
  • Finally, a yacaré distribution model has been developed to estimate the exploitation potential and determine quotas at the basin and micro-basin level in the yacaré distribution departments. This model is currently under review.From the completion of this study, it will be possible to define and regulate the catch quotas by the Ministry of the Environment and Water of Bolivia (MMAyA for its acronym in Spanish)

Photo: Mariana Escobar W-W

 

Published in the Bioamazon Newsletter, edition n. 10, July-August 2021.

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