Sayonara ASPIC and Welcome JABBA to SEAFDEC

Abstract

Sayonara ASPIC and welcome JABBA A Stock Production Model Incorporating Covariates (ASPIC) is one of the surplus production models (SPMs). It has been used in SEAFDEC over the past decade primarily for neritic and oceanic tuna but has recently become outdated theoretically and practically. In contrast, Just Another Bayesian Biomass Assessment (JABBA) is a more recent SPM that can offer more reliable, robust and plausible results. For this reason, the authors strongly recommend that fish stock practitioners switch from ASPIC to JABBA.

Routine assessments using the JABBA-HCR approach Based on past experience, it has been observed that participants, during and especially after stock assessment training sessions organized by SEAFDEC, require the assistance of resource persons to carry out proper, reliable and plausible stock assessments. This situation will continue even if JABBA is introduced. In addition, in previous SEAFDEC meetings, recommendations were made to conduct routine stock assessments for important species (neritic tuna), which are still pending. To address these issues, the introduction of routine stock assessments using the JABBA-Harvest Control Rule (HCR) approach needs to be considered. A simple HCR can derive catch limits or Total Allowable Catch (TAC) using only catch or CPUE without conducting full stock assessments. Hence, this approach can be implemented by stock assessment practitioners in the SEAFDEC Member Countries without the assistance of resource persons.

Implementing the JABBA-HCR approach The initial stage of implementing the JABBA-HCR approach should prioritize the unhealthy stocks in the most important species. As an example, it can be carried out as follows: (1) JABBA will be conducted with the assistance of resource persons every three years; and (2) during the two years between these assessments, SEAFDEC can independently implement annual HCRs to derive the TAC without the assistance by resource persons (refer to the text for the healthy stock case). This will enable routine assessments in a timely and cost-effective manner while complying with pending recommendations. This effort is vital for SEAFDEC to fulfil its mission of securing sustainable food sources and livelihoods for its Member Countries.

Sustainable capacity building framework This framework is designed to supervise trainees’ stock assessment work continuously, especially after the training, to ensure that they achieve satisfactory proficiency. In this regard, Thailand, Indonesia, Sri Lanka and the Republic of Korea have shown strong interest in this approach and have requested to carry it out. Between 2024 and 2026, eight face-to-face training sessions were conducted with 49 participants. The initial sessions mainly comprised lectures and practices for the newly developed menu driven JABBA software. This software makes it possible to implement proper, transparent and reliable assessments smoothly. During the initial training sessions, a few important species were selected in each country and preliminary assessments were carried out. Afterwards, online training and discussion sessions have been implemented for 1–3 years to complete the full assessment work. In addition, to demonstrate their proficiency, they were asked to write scientific papers to submit to international peer-reviewed journals. Unlike the normal snapshot-type training, this approach enables continuous collaboration between stock assessment practitioners and resource persons, ensuring its sustainability. Some of their achievements are introduced and referenced in this article. Implementing this approach in SEAFDEC will be quite challenging or impossible under its current structure.

Two main issues with JABBA In summary, the authors address two important issues to initiate JABBA-related activities: (1) routine assessments by the JABBA-HCR approach under the current SEAFDEC structure; and (2) sustainable capacity building framework with JABBA and other models through long-term supervision. It includes follow-up online training and discussion sessions as well as publication support to ensure assessments conducted are proper, reliable and plausible.