Quantification has long been an important issue in larval dispersal research. The Japanese anchovy (Engraulis japonicus) is one of the most ecologically and economically important small pelagic fish in the China Seas. However, a comprehensive and quantitative understanding of its larval dispersal patterns and underlying drivers has been lacking. This manuscript applies both 1D and 2D dispersal kernels to give a high spatiotemporal resolution, multi-factor, quantitative analysis of larval dispersal in Japanese anchovy across the China Seas, providing some new insights into the quantification of larval dispersal patterns. It also reveals the critical connectivity role of the Changjiang Estuary spawning ground, which is quite interesting and beyond expectations. However, I still have some concerns on the manuscript, and addressing them would, in my view, improve its quality.

Main concerns:

1. What is the meaning of connectivity matrix?

Connectivity matrices have been used primarily for reef fish, where reef areas can function simultaneously as spawning grounds and nursery grounds. In this study, the y‑axis of connectivity matrices represents spawning locations, but the x‑axis represents settlement locations rather than nursery grounds. What, then, is the meaning of connectivity between a spawning location and a settlement location?

I suggest that the authors provide a more detailed explanation of the connectivity matrices, including their ecological interpretation and limitations.

1. Are Chinese stock and Japanese stocks connected through CJ ground?

I do not think that the connectivity (dispersal rate) of larvae from the CJ spawning ground to the TWC and PS spawning grounds is sufficient to prove that the Chinese stock and the Japanese stock are connected. Although some larvae originating from CJ may reach the TWC region, larvae spawned at TWC may already have been advected further eastward by that time, resulting in limited spatial or temporal overlap between the two groups. Under such circumstances, the mere arrival of CJ larvae at TWC does not necessarily imply effective stock connectivity. Stronger evidence would come from demonstrating that larvae originating from CJ and TWC are transported to the same or nearby nursery habitats and overlap in space and time, thereby increasing the likelihood of mixing and subsequent recruitment into a common population. Such convergence of dispersal trajectories would provide a more convincing mechanism linking the two stocks.

I suggest that the authors discuss this point and greater caution should be exercised in both the wording and the conclusions of the manuscript, particularly when inferring stock connectivity from modeled dispersal pathways alone.

Minor suggestions:

L21: pattern, instead of patten.

L21: ranges from 44.53 to 150.56, replace “-” with “to”.

L100: hydrodynamic model, instead of modal.

L128: you said “30 days” in L81, but why you used 30, 40, 50, 60 days here.

L130: 15 times, instead of 15 days.

L131: The position of a particle stopped at the end…

L255-260: I think you need a Table S2 to give the values of modal dispersal distance, median-dispersal distance, and long-distance dispersal. It’s hard to read these values from the figure.

L372: dispersal kernels, instead of dispersal kernel.

L365: need a figure S2 to show the correlation between individual dispersal distances and PLD.

L366: The suggestion that PLD is not a reliable predictor of dispersal distance at the individual level, yet can capture broad average trends in dispersal potential, is interesting. Alvarez-Noriega et al. (2020), in their study "Global biogeography of marine dispersal potential," used PLD multiplied by average flow velocity to estimate mean dispersal distance and quantified the overall latitudinal gradient in larval dispersal distance. You could discuss this study to further contextualize or support your findings.

L402: as stated above, you can change the descriptions here, for example, we suggest that they may be connected through Changjiang spawning ground.

This study employs a Lagrangian particle tracking model to simulate larval dispersal processes and uses a suite of statistical approaches to characterize dispersal patterns. Clarifying larval dispersal pathways in this manuscript is undoubtedly valuable for understanding recruitment dynamics and informing fisheries management. Nevertheless, several methodological limitations should be acknowledged. Moreover, the overall analyses and conclusions could be substantially strengthened through more rigorous treatment and deeper conceptual integration.

The hydrodynamic model used here has been validated against observed current velocity at selected stations in the previous publication. Given that this study relies heavily on particle transport pathways, it would be highly desirable to compare modeled trajectories with surface drifter observations. Such a validation would greatly enhance the credibility and robustness of the particle tracking simulations.

A point of ambiguity concerns the origin of the particle tracking data: were the larval trajectories directly adopted from Xing et al. (2020; 2021), or did the authors perform their own tracking using the hydrodynamic fields from those studies? This should be clarified in the Methods. Additionally, the hydrodynamic model in Xing et al. (2020) covers 1992–2018, whereas the manuscript states 1987–2018; this discrepancy needs to be addressed. The rationale for splitting the study period into 1987–2004 and 2016 also requires explanation.

The spawning grounds, named the initial positions in the model, partially determine dispersal pathways and settlement distributions. However, the spawning grounds are approximated as simple rectangles without considering bathymetric constraints, and their spatial extents are not fully consistent with those in Xing et al. (2020; 2021) or the cited references. A more thorough justification for the chosen spawning grounds geometries is required.

In field surveys, eggs are distributed heterogeneously, yet particles are released uniformly across the spawning areas. The results uncertainty introduced by this simplification should be assessed or at least discussed.

The manuscript states that larvae are released in the near-surface layer, but the exact release depth is not specified—whether at the uppermost sigma level of FVCOM model or at a fixed depth (e.g., 1 m). Given that horizontal velocity varies vertically, the tracking depth selection can substantially influence transport pathways. Therefore, a clear specification is required.

The key conclusions are largely predictable: spawning grounds dominating the dispersal pattern is unsurprising given the wide spatial separation of grounds and complex coastal circulation; larvae from the Changjiang Estuary can spread into the Japan Sea through the Tsushima Strait, which has been demonstrated by float drifters and tracking models (e.g., Moon et al., 2010, particle tracking for jellyfish). The finding that interannual variability contributes least should be interpreted carefully, as the model's ability to reproduce realistic interannual circulation variability has not been independently validated. Further, interannual variations of spawning grounds and egg numbers are ignored in this study. Analysis of seasonal and interannual variations of dispersal patterns should be accompanied by more specific discussions of the circulation dynamics (also plotting some current figures). Moreover, simulated settlement patterns should be discussed against observational data, to examine whether they are reasonable.

Some specific comments:

In Section 3.1 and Figure 2, it should be stated whether the settlement pattern is from a single model case or integration of all experiments.

In Section 2.6, the sentence "The factors included spawning ground, travel duration, spawning year and spawning month" is redundant and should be deleted.

Citations of Xing et al. (2020) and Xing et al. (2021) should be formatted as Xing et al. (2020; 2021).

In the reference list, Chinese author names such as Hao, W., Jian, S., Ruijing, W., Lei, W., and Yi'an, L. appear to have given and family names reversed.