1. Cooperation, Public Relations
  2. Press Release
  3. 2025

研究成果

Elucidating the Life History of Small Freshwater Shrimp Species Macrobrachium lanchesteri for Resource Management
–Paving the Way for Sustainable Use of Important Freshwater Shrimp Resources in the Indochina Peninsula–

press202528.pdf1.41 MB

2026-03-12
Japan International Research Center for Agricultural Sciences (JIRCAS)
Ubon Ratchathani University

Key Points

  • Aimed to elucidate the life history—including spawning, growth, and recruitment—of small freshwater shrimp, Macrobrachium lanchesteri, an important fisheries resource in the inland regions of the Indochina Peninsula, throughout an entire year.
  • Demonstrated for the first time that, while small freshwater shrimp spawn year-round, spawning peaks mid-rainy season (June–August) and stagnates in the dry season (November–December).
  • Confirmed the effectiveness of current rainy-season no-fishing period regulating commercial fisheries in conserving spawning adult shrimp, and proposed new resource management measures of avoiding capture of immature juveniles.

Overview

JIRCAS, in collaboration with Ubon Ratchathani University in Thailand, has clarified the life history characteristics of small freshwater shrimp, Lanchester’s Freshwater Prawn (Macrobrachium1 lanchesteri) species complex, in Northeast Thailand, an important fisheries resource in the inland Indochinese Peninsula. These shrimp are common freshwater species supporting local food culture and livelihoods, and their sustainable use requires scientific information on when they spawn and how long it takes until they become available to fisheries.

In this study, specimens were collected monthly over one year in Ubon Ratchathani Province, Northeast Thailand, and analyzed for individual size and maturity status. Results showed that while the small freshwater shrimp spawn year-round, peak spawning occurs during mid-rainy season from June to August, and spawning stagnates during the dry season from November to December. Hatched shrimp begin appearing in catches as small immature individuals from September to November (recruitment2), and it was revealed that they mature and spawn in less than a year after hatching, between March and May of the following year.

While previous studies had shown that small freshwater shrimp spawn year-round like many other tropical Macrobrachium species, the existence or timing of a spawning peak remained unclear. Consequently, the effectiveness of the rainy-season no-fishing period regulating commercial fisheries (artisanal fisheries excluded) across inland Thailand had not been verified for this species’ resources. This study demonstrated that the no-fishing period in the region coincides with the spawning peak of the shrimp, confirming the effectiveness of the current regulation in conserving adult shrimp. Furthermore, since small immature shrimp begin joining fisheries stocks around September and mature the following spring, avoiding their capture during this period was suggested as an additional effective resource management strategy. Such resource biology information is critically important for designing effective management measures that are in line with the species’ life history traits, and is expected to contribute to the sustainable use of small freshwater shrimp resources in the inland Indochinese Peninsula.

The results of this research have been published as an open-access article in the online edition of the international fisheries journal, Fisheries Research (October 29, 2025, JST).

Related Information

Funding
Operating Expenses Project:「Development and Dissemination of Sustainable Aquaculture Technologies in the Tropical Area Based on the Ecosystem Approach」

Publication Information

Authors
Minoru Saito, Chaiwut Grudpan, Jarungjit Grudpan, Achara Jutagate, Satoshi Honda, Tuantong Jutagate
Title
Life history aspects of the small freshwater shrimp, Macrobrachium lanchesteri species complex (Palaemonidae)
Journal
Fisheries Research
DOI: https://doi.org/10.1016/j.fishres.2025.107569

Contact

JIRCAS President: KOYAMA Osamu

Program Director: 
FUJITA Yasunari
Research Staff: 
SAITO Minoru (Researcher, Fisheries Division)
HONDA Satoshi (Project Leader and Director, Fisheries Division)
Press Coordinator: 
OMORI Keisuke (Head, Information and Public Relations Office)
Press e-mail : info-pr@jircas.go.jp

Terminology

1 Macrobrachium
A group (genus) of shrimp commonly exploited as fisheries resources in various parts of the world, including Japan. More than 200 species are distributed from shallow seas to the inland areas of continents, and a distinguishing feature is the long, well-developed claws (chelae) of the males. The Giant Freshwater Prawn (M. rosenbergii and M. dacqueti), widely cultured in Southeast Asia, is the largest species, reaching 1 m from claw tip to tail tip. Smaller species measure around 5 cm in total length.
2 Recruitment
From a fisheries science perspective, it refers to reaching the stage subject to capture following growth or migration; from a zoological viewpoint, newly joining a population (e.g., by birth, reaching a certain size/form, or immigration). In the case of the small freshwater shrimp, where larvae and adults inhabit the same environment, “recruitment” corresponds to the stage ≤2–3 months post-hatching when they grow to harvestable size.

Related Pages