23 September 2026
IFOP’s Monitoring and Surveillance Program for Mytilid Larval Availability—currently in its Stage XIV since March 2026—has detected a sharp increase in mussel larvae, with counts exceeding 500,000 larvae per cubic meter in Pichicolo. Starting in mid-August and early September, researchers began detecting the presence of pre-competent mussel larvae, marking the first signs of new reproductive events for the species.
Since March of this year, the Fisheries Development Institute (IFOP)—through the Environment Department of its Aquaculture Research Division—has been conducting Stage XIV of the Monitoring and Surveillance Program for Mytilid Larval Availability, continuing a monitoring series that has been underway in the Los Lagos Region since 2013.
During the initial months of this stage, sampling across the various monitoring sites did not record significant abundances of mussel (*Mytilus chilensis*) larvae. This situation persisted until mid-August, when researchers began to observe changes in larval dynamics.
Consequently, from mid-August onwards—with increasingly clear evidence by early September—the presence of pre-competent mussel larvae has been recorded. This serves as a significant signal within the species’ reproductive cycle and indicates that new gamete releases have occurred in the natural populations being monitored. A signal marking a key moment in the reproductive cycle
The detection of pre-competent larvae is a particularly important indicator for tracking the season, as it signals that the reproductive process has reactivated following a period of low larval abundance. Analysis reveals isolated records of pre-competent larvae in June—99.03 larvae/m³ in Castro and 1,372.27 in Compu—followed by a marked shift in larval dynamics starting in August, and notably, an extraordinary surge in early September 2026. The jump from August to September 2026 is quantified by the rise from 2,382 larvae/m³ in Compu to 509,024 in Pichicolo and 209,966 in Hornopirén.
However, the presence of these larvae does not in itself imply the immediate onset of seed collection. It serves as an early signal that requires follow-up monitoring over the coming weeks to track changes in abundance and determine the larvae’s progression toward more advanced developmental stages—and eventually toward competence and settlement.
From spawning to settlement: a process requiring monitoring. Continuous monitoring allows us to observe how this process unfolds over time across different sectors of the Los Lagos Region, bearing in mind that reproductive and larval dynamics can vary significantly across locations and seasons. The data from Hornopirén underscore the scale of the phenomenon, while the other stations demonstrate that this is not merely an isolated occurrence.
Key information for mussel farming
For the mussel farming industry, timely knowledge of larval dynamics is crucial, given that a significant portion of mussel production relies on the natural availability of seed and its subsequent capture using collectors. In this context, the program’s results provide scientific information regarding when changes in larval abundance begin to appear, how these events are distributed across the region, and how the various stages of larval development progress.
This information is particularly significant at this time, as the first records of pre-competent larvae begin to signal a shift from what was observed in previous months. Monitoring will continue over the coming weeks to determine whether these initial signs translate into a sustained increase in larval abundance and the subsequent appearance of larvae competent for settlement.
Over a Decade of Tracking Larval Dynamics
IFOP’s Monitoring and Surveillance Program for Mytilid Larval Availability has been running continuously since 2013, serving as a long-term source of scientific data for understanding the reproductive and larval dynamics of mytilids in the Los Lagos Region.
The continuity of this monitoring allows for the comparison of behavior across different seasons and the identification of natural variability in reproductive processes, generating data that contribute to better planning for seed collection activities.
Results are made available to users via *Semilla Endémica*, a platform developed by IFOP that facilitates the visualization of data regarding larval abundance and other relevant information for tracking seed availability.
Thus, as the 2026–2027 season progresses, IFOP continues to monitor mytilid larval dynamics in the Los Lagos Region, paying close attention to how the initial signals observed during August and September evolve.
Upcoming sampling events will be crucial for determining how these abundance levels change and whether the early signals currently observed translate into greater availability of larvae in advanced developmental stages—information that is vital for the mussel farming sector and for understanding the natural cycles underpinning this industry.
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