Terrestrial aquaculture and agriculture in Rondônia: an economic analysis

Last registered on July 23, 2026
View Trial History

Pre-Trial

Trial Information

General Information

Title
Terrestrial aquaculture and agriculture in Rondônia: an economic analysis
RCT ID
AEARCTR-0019218
Initial registration date
July 22, 2026

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
July 23, 2026, 8:28 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Locations

Country
Brazil
Region
State of Rondônia

Primary Investigator

Name
Thiago Morello
Affiliation
Federal University of ABC
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Ethan Addicott
PI Affiliation
University of Exeter
Contact Investigator
PI Name
Paula Pereda
PI Affiliation
Department of Economics, University of São Paulo
Contact Investigator

Additional Trial Information

Status
In development
Start date
2026-07-27
End date
2026-11-30
Keywords
Agriculture, Environment & Energy
Additional Keywords
JEL code(s)
Q22, Q01, C25
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Fish-farming is growing worldwide, especially in developing countries, where it is becoming an alternative source of protein comparable to cattle rearing. Fish farming is also expanding in the Brazilian Amazon, where cattle rearing remains the main usage of already deforested land. Nevertheless, in such region, many barriers prevent fish-farming from becoming comparable to cattle in terms of farm profit and protein supply. The main barriers being the high market risk, due to a still incipient regional/national market, the lack of skilled labour, and the scale economy implied together with lacking credit access. Upon this background, we ask two research questions, having as our target subject the average Rondônia farmer with minimal fish-farming knowledge. First, what is the willingness to accept compensation (WTA) for up-taking a contract offered by a hypothetical new processing plant, as means to increase the share of farmland occupied with sustainable fish farming? Second, which are the marginal utilities for the five key attributes capturing the trade-off between (i) non-monetary costs of adopting good and sustainable fish-farming practices and (ii) better conditions for selling fish and purchasing inputs? These key attributes are: (i) required pond area to be built in the farm, (ii) good and sustainable fish-farming practices, (iii) practice non-compliance penalty, (iv) environmental sustainability label and (v) supplementary payment for fish delivered.
We test ten main hypotheses, namely: (1) the average WTA is statistically significant and larger than the maximum level of profit yielded by fish-farming in the study region, (2) the propensity for up-taking a contract is statistically equal among classes of fish-farmers, (3) marginal utility for required pond area is null, (4) marginal utility for good practices is null, (5) marginal utility for non-compliance-penalty is null, (6) marginal utility for the environmental sustainability label is null, (7) marginal utility for the supplementary payment is null, (8) marginal utility for a contract-based alternative (i.e., the reverse of the status-quo) is null, (9) smallholders not having fish-selling experience are not more likely to opt-out of contracts, and (10) cattle ranching and fish-farming are substitutes when taking all farmers as a whole, but become complements at large farm sizes. A sample of farms with satellite-detected ponds is randomly selected for interviews. All respondents are interviewed in-person and on-field by the research team and hired enumerators. By the time of this registration, only the pretest (pilot) survey was conducted (the full-fledged survey was planned to take place after this registration).
External Link(s)

Registration Citation

Citation
Addicott, Ethan, Thiago Morello and Paula Pereda. 2026. "Terrestrial aquaculture and agriculture in Rondônia: an economic analysis." AEA RCT Registry. July 23. https://doi.org/10.1257/rct.19218-1.0
Sponsors & Partners

Sponsors

Partner

Name
Bussola.Farm
Type
private_company
URL
https://bussola.farm/
Experimental Details

Interventions

Intervention(s)
Our intervention is a discrete choice experiment (DCE) conducted with a sample of farmers having a satellite-detected pond in their farm. The DCE is conducted as an in-person interview on-field in rural areas of Rondônia state, western Brazilian Amazon. The good valued is a contract requiring that sustainable fish farming be expanded in the farm and offering better sales and input access conditions. The background scenario is the arrival of a new fish processing plant in the region.
At baseline and endline, respondents are exposed to the DCE, which contains five attributes, presented as characteristics of a fish sales contract: (i) size of new earthen ponds required to be built in farm, (ii) good fish-farming practices required; (iii) (monetary) penalty for non-compliance with the practices, (iv) environmental sustainability label, (v) supplementary payment for fish delivered. These attributes are presented in five choice sets, each with three alternatives. Two of the alternatives are two contracts (different combinations of attributes' levels) and the third is the option for not signing a contract (status quo or "opt-out" option). There are also four attributes that do not vary across contract-based alternatives: (i) contracts' five-year term, (ii) fish to be sold coming exclusively from the new ponds, (iii) need to request an environmental license for the new pond, (iv) full coverage of the production cost. Besides choosing the most preferred alternative in the choice sets, the questionnaire requires data about (1) experience with fish farming, (2) attitude regarding contracts, (3) socioeconomic and land usage profile, (4) self-evaluation of the interview by the enumerator.

Intervention Start Date
2026-07-27
Intervention End Date
2026-11-30

Primary Outcomes

Primary Outcomes (end points)
(1) Willingness to accept monetary compensation to uptake a contract, (2) marginal values of the contract's attributes (pond area required, good practices required, non-compliance penalty, environmental sustainability label, supplementary payment; and as well as a binary variable identifying contract-based alternatives) and (3) contract uptake proportion.
Primary Outcomes (explanation)
Willingness to accept a contract will be constructed by estimating a willingness-to-pay-space mixed logit, and by multiplying the estimated coefficients for the levels of the attributes of all contracts offered (in that case, all respondent-specific coefficients will be used). We will also employ alternative, non-mixed logit, coefficient estimates, such as those coming from latent class logit, conditional logit, generalised multinomial logit and other estimators that achieve an acceptable degree of fitness to our data.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Regarding sampling, respondents were selected from a third-party (private company, Bussola.Farm) georeferrenced dataset containing spatial points (geographical coordinates) where water ponds were detected with high-resolution satellite imagery. The data was confidentially shared with the principal investigator (PI). The PI eliminated water ponds classified as inactive fishing ponds in the original data, and kept only the points within 15 km of the boundaries of the Ariquemes municipality (this municipality is a top producer of farmed fish of Rondônia state). From these points, the farms visited in the pretest and full-fledged survey were selected.
A D-efficient design was employed to select the levels of the five attributes for each contract-based alternative of the choice set (Stata's user-written dcreate package was used). The data will be analysed with mixed-logit (allowing for random marginal utility coefficients), latent class logit, conditional logit and (generalised) multinomial logit estimators (other estimators may be also used). Hypotheses will be tested based on point estimates and standard errors generated by the estimators.
In particular, we test ten main hypotheses, namely: (1) the average WTA is statistically significant and larger than the maximum level of profit yielded by fish-farming in the study region, (2) the propensity for up-taking a contract is statistically equal among classes of fish-farmers, (3) marginal utility for required pond area is null, (4) marginal utility for good practices is null, (5) marginal utility for non-compliance-penalty is null, (6) marginal utility for the environmental sustainability label is null, (7) marginal utility for the supplementary payment is null, (8) marginal utility for a contract-based alternative (i.e., the reverse of the status-quo) is null, (9) smallholders not having fish-selling experience are not more likely to opt-out of contracts, and (10) cattle ranching and fish-farming are substitutes when taking all farmers as a whole, but become complements at large farm sizes.
Experimental Design Details
Not available
Randomization Method
Randomization of sample done in office by a computer with the R software random numbers generator. DCE design based on Stata's dcreate user-written package, also done in the office.
Randomization Unit
Satellite-detected pond.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
Discrete choice experiment: NA
Sample size: planned number of observations
Discrete choice experiment: 225
Sample size (or number of clusters) by treatment arms
Discrete choice experiment: 225 (only one arm); this is the planned sample size; a smaller sample (of, for instance, N = 135), may be imposed by budgetary limitations and difficulties faced during on-field data collection (especially long distances).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Committee of Ethics in Research with Human Beings of the Federal University of ABC (UFABC), at São Paulo state, Brazil, in behalf of the Brazilian National Commission on Ethics in Research (CONEP).
IRB Approval Date
2026-06-24
IRB Approval Number
97772026.1.0000.5594
Analysis Plan