By explicitly coupling propulsion-choice experiments with a latent-variable model of acceptance and guide professionalism, the study reframes lagoon boating impacts as a socio-ecological systems problem in which technology adoption, operator practice, and visitor perceptions co-determine environmental outcomes. This integration extends prior boat-noise research—largely biophysical or perception-only—toward governance-relevant design.
3.1. Descriptive Statistics and Demographics
The sample consisted of 801 participants with a female majority. The majority of the was female (60.4%) and married (72.3%). The majority held university degrees (66.5%), with income levels predominantly in the lower-middle range. Only 23.3% of participants had previously attended environmental education courses (
Table 1). All constructs demonstrated adequate reliability with Cronbach’s α values exceeding 0.80 (
Table 2). Composite reliability (CR) values ranged from 0.803 to 0.965, and average variance extracted (AVE) values exceeded 0.50, supporting convergent validity (
Table 3). Diagonal elements are square roots of AVE values (
Table 4). The structural model demonstrated excellent fit indices, supporting the validity of the proposed theoretical framework (
Table 5). This study investigated the hierarchical experience process in sustainable tourism education within guided tours of aquaculture-based lagoons for recreational fishing boats, focusing on the ecological impacts of two types of pontoon boats: those equipped with environmentally friendly electric motors and those using traditional internal combustion engines. Structural equation modeling revealed that experiential service quality, associated with electric motor pontoon boats, exerted a stronger positive effect on the experience hierarchy (β = 0.287,
p < 0.001) compared to functional service quality linked to traditional engine pontoon boats (β = 0.156,
p < 0.001), underscoring the superior role of low-impact propulsion in fostering environmental knowledge, attitudes, P-PLG, flow experiences, and conservation behaviors (
Table 5) (
Figure 2).
The sequential mediation model demonstrated robust pathways from environmental education participation—delivered through interpretive guided tours—to pro-environmental outcomes. Participation directly enhanced environmental knowledge about lagoon ecosystems and motor impacts (β = 0.234,
p < 0.001), which in turn shaped attitudes toward sustainable boating practices (β = 0.456,
p < 0.001) (
Table 5). These attitudes strengthened perceived professional level of tour guide to aquaculture lagoons (β = 0.523,
p < 0.001), promoting immersive flow experiences during tours (β = 0.387,
p < 0.001) and ultimately driving intentions for conservation behaviors, such as adopting electric motors (β = 0.534,
p < 0.001). Mediation analysis confirmed partial mediation for the full hierarchy (indirect effect = 0.145, 95% CI [0.089, 0.201]), indicating that tours using electric motors amplified ecological awareness by minimizing noise and emissions, thereby facilitating deeper cognitive and affective engagement (
Table 6). This aligns with the dual service quality framework, where electric pontoon boats enabled interactive, personalized experiences (e.g., silent observation of aquatic species), contrasting with the efficiency-focused but pollutant-emitting traditional engines, which disrupted ecosystem immersion (
Table 7). The significant moderation effects indicate that adequate safety perception and facility quality are necessary conditions for service quality to effectively influence flow experiences (
Table 8).
These findings elucidate mechanisms underlying the differential ecological impacts of pontoon boat propulsion types. Electric motors reduced direct disturbances to lagoon biodiversity, as evidenced by lower noise pollution and zero hydrocarbon emissions, fostering greater participant flow and conservation intentions. Traditional engines contributed to water contamination and acoustic interference, weakening attitudinal shifts (as per the lower β for functional quality). This disparity supports theoretical models of experiential learning in ecotourism, where low-impact technologies enhance emotional connections to fragile aquaculture environments, potentially mitigating overfishing and habitat degradation in recreational settings. The new data align with previous observations [
70,
71].
Comparisons with existing literature reveal consistencies and novel contributions. Prior studies on boating impacts in coastal ecosystems, such as those by [
72,
73], document how internal combustion engines exacerbate pollution in lagoons, aligning with the observation of diminished experiential outcomes in traditional pontoon boat tours. Similarly, Ref. [
74] emphasized cumulative stressors from recreational boating, where emissions from gasoline motors degrade water quality, corroborating the data on weaker mediation effects for functional service quality. However, the results diverge from earlier work like [
75], which found no significant behavioral changes from eco-friendly interventions in marine tourism, possibly due to their focus on open-ocean contexts lacking the enclosed dynamics of aquaculture lagoons. In contrast, studies on electric propulsion in small vessels, including [
76,
77], report reduced ecological footprints, consistent with the stronger β for experiential quality, but the hierarchical model extends this by quantifying sequential cognitive-behavioral pathways, filling a gap in integrating education with propulsion technology.
Further alignment emerges with research on sustainable aquaculture tourism. For instance, Ref. [
78] highlighted how guided tours in shellfish farms promote awareness of ecosystem services, mirroring the knowledge-to-attitude pathway, yet this study innovates by contrasting motor types, revealing that electric pontoon boats amplify perceived professional level of tour guide more effectively than traditional ones, as supported by lower disturbance to fish stocks noted in [
79]. Differences appear in comparisons with recreational fishing impacts; Refs. [
80,
81] identified angling pressures in lagoons but overlooked propulsion effects, whereas the SEM approach demonstrates how electric motors mitigate these through enhanced flow experiences, addressing a methodological limitation in their survey-based designs (
Figure 2). High-impact analyses, such as those by [
82] on global fishing footprints, underscore vessel emissions as key stressors, reinforcing the findings, though the localized lagoon focus provides granular insights absent in broad-scale models. Overall, this research bridges gaps in 15 recent studies (e.g., [
83,
84]), innovating through duality theory application to pontoon boat technologies and SEM validation in aquaculture contexts.
The bootstrapped mediation analysis [
50] enhances generalizability across contexts, addressing methodological scalability via standardized protocols.
3.2. Anthropogenic Impacts, Ecosystem Resilience, and Underwater Monitoring
A total of 68 fish species were identified across the three sampling sites (Eco: eco-friendly motor; ICE: traditional internal combustion engine motor; Control: no motor). Site Eco exhibited the highest species richness (n = 62 species with non-zero abundance), followed by Site Control (n = 58) and Site ICE (n = 28), indicating a potential reduction in detectable species diversity at the site exposed to traditional motor noise (Table 10). Total fish abundance followed a different pattern, with Site Control highest, followed by Eco, and ICE lowest, with Site Eco recording 1182 individuals, Site Control with 1678, and Site ICE with only 253, suggesting that traditional motor use may suppress overall fish abundance compared to the eco-friendly motor or control (
Figure 3 and
Figure 4).
To assess community structure differences, non-metric multidimensional scaling (NMDS) was applied to species abundance data using Bray–Curtis dissimilarity (stress = 0.12, indicating a reliable ordination) [
51]. The NMDS plot revealed clear separation between Site ICE and the other sites, with Sites Eco and Control clustering closely. Due to the three replicates per site, permutation-based multivariate analysis of variance (PERMANOVA) was feasible; however, pairwise Bray–Curtis distances showed greater dissimilarity between ICE and Control (0.68) than between Eco and Control (0.32), supporting qualitative evidence of impact from traditional motors. Shannon diversity indices (H’) were calculated as follows: Site Eco (H’ = 3.45), Site ICE (H’ = 2.78), Site Control (H’ = 3.62). Wilcoxon rank-sum tests (non-parametric, due to non-normal data distribution confirmed by Shapiro–Wilk tests,
p < 0.05) on abundance per species indicated significantly lower median abundance at Site ICE compared to Site Control (Z = −2.87,
p = 0.004), but no significant difference between Site Eco and Site Control (Z = −0.92,
p = 0.36). Kruskal–Wallis tests across all sites confirmed overall differences in abundance (χ
2 = 12.4, df = 2,
p = 0.002), with post hoc Dunn’s tests highlighting ICE vs. Control (
p = 0.001) and ICE vs. Eco (
p = 0.003) as significant.
Body length data were available for five dominant species:
C. macrolepis,
N. come,
G. erythrourus,
Oreochromis sp., and
M. cephalus (n = 182, 189, 251, 191, and 125 measurements at Site Eco, respectively) (
Figure 4). Mean body lengths (±SD) varied across sites (Table 11). For instance,
C. macrolepis showed reduced mean lengths at Site ICE (24.5 ± 8.2 cm) compared to Site Eco (33.1 ± 7.9 cm) and Site Control (34.2 ± 8.5 cm).
Non-parametric Kruskal–Wallis tests revealed significant differences in body lengths across sites for all species (p < 0.001; Table 11). Post hoc pairwise Mann–Whitney U tests (Bonferroni-corrected) indicated that traditional motor exposure (Site ICE) significantly reduced body lengths compared to the control (Site Control) in C. macrolepis (U = 1245, p < 0.001), N. come (U = 1112, p = 0.002), G. erythrourus (U = 987, p < 0.001), O. sp. (U = 1456, p = 0.004), and M. cephalus (U = 1023, p = 0.001). In contrast, eco-friendly motor exposure (Site Eco) showed no significant differences from Site Control for any species (p > 0.05), suggesting minimal impact.
Multivariate analysis via principal component analysis (PCA) on standardized body lengths across species explained 68% of variance in the first two axes, with PC1 (45%) loading positively on larger sizes in Sites Eco and Control, and negatively on-Site ICE (
Figure 4). PERMANOVA on Euclidean distances confirmed significant effects of motor type (F = 8.76, df = 2,
p = 0.001, 999 permutations), with pairwise contrasts showing ICE vs. Control (
p = 0.002) and ICE vs. Eco (
p = 0.003) as drivers (
Figure 5). The figure shows species composition of the top 12 taxa + other (remaining taxa aggregated), with unique colors for each taxon and species names in legend.
Figure 6 shows non-metric multidimensional scaling (NMDS) ordination based on Bray–Curtis dissimilarity of species abundance data (stress = 0.12, indicating good representation in two dimensions). Each point represents a monthly sampling event (n = 5 months × 3 sites = 15 total). Dashed ellipses show 95% confidence intervals around site centroids. Vector arrows indicate species contributing >10% to between-site differences based on SIMPER analysis [
52], with arrow length proportional to correlation strength. Clear spatial segregation demonstrates significant differences in community structure among sites (PERMANOVA: pseudo-F
2,
12 = 8.47,
p < 0.001, R
2 = 0.53). The ordination reveals that Site ICE assemblages are consistently distinct from Sites Eco and Control, while the latter two show partial overlap, suggesting intermediate similarity in community composition. NMDS2 = second axis; Stress = 0.12 indicates goodness-of-fit.
In this study, underwater imagery was analyzed to assess fish abundance and body length (
Figure 7). The results are visualized through box plots that show the total length distributions for four species with adequate sample sizes. Box plots showing total length distributions across sampling sites for four species with adequate sample sizes. Boxes represent interquartile ranges (25th–75th percentiles), horizontal lines indicate medians, whiskers extend to 1.5 × IQR, and outliers are shown as individual points. Different letters above boxes indicate significant differences (
p < 0.05, Kruskal–Wallis test with Bonferroni-corrected Dunn’s post hoc test for multi-site comparisons, Mann–Whitney U test for two-site comparisons). Sample sizes shown in parentheses below site labels. Site ICE data are absent for
G. throwers and
O. sp. due to insufficient captures (n < 5). The consistent pattern of reduced body sizes at Site ICE across multiple species provides convergent evidence for growth-limiting environmental conditions. Box plots showing total length distributions for four target species across sampling sites. Boxes show interquartile ranges, horizontal lines indicate medians, whiskers extend to 1.5 × IQR, and circles show outliers. Different letters above boxes indicate significant differences (
p < 0.05, Kruskal–Wallis with Bonferroni-corrected Dunn’s test). Sample sizes shown in parentheses. Site ICE data absent for Greenery throwers and Oreochromis sp. due to insufficient captures. Anthropogenic impacts and ecosystem resilience.
The rationale for using two methods to monitor body length is: net sampling for community-level abundance and diversity, underwater video for species-specific behavioral responses. Important differences: nets provide quantitative catch data, video captures in situ behavior without extraction. Segregation was for clarity, but integration here invites comparisons.
The spatial scale of variation observed in this study (<5 km) emphasizes the localized nature of anthropogenic impacts in coastal lagoon systems and highlights the importance of fine-scale habitat heterogeneity for maintaining regional biodiversity [
85]. The contrasting patterns between Sites Eco and Control suggest that well-managed eco-tourism activities may be compatible with biodiversity conservation, providing a potential model for sustainable coastal zone management [
9,
86].
Site Eco’s intermediate diversity patterns may reflect the dual influences of tourism-related nutrient inputs and active management through eco-friendly motor restrictions. While boat traffic can alter sediment dynamics and introduce contaminants, the observed maintenance of high species richness (60 species) suggests that current management practices are effectively mitigating negative impacts [
87]. The dominance structure at this site, characterized by high abundances of both native (
N. come,
C. macrolepis) and non-native (
O. sp.) species, indicates a transitional state that warrants continued monitoring (
Table 9,
Table 10 and
Table 11). Field observations revealed that docks utilizing low-frequency, environmentally friendly motors harbored significantly richer fish assemblages, with fish abundance 61% higher and mean body length 38% greater compared to docks using conventional motors (
Figure 8).
Non-metric multidimensional scaling (NMDS) ordination based on Bray–Curtis dissimilarity of species abundance data (stress = 0.12, indicating good representation in two dimensions). Each point represents a monthly sampling event (n = 5 months × 3 sites = 15 total). Dashed ellipses show 95% confidence intervals around site centroids. Vector arrows indicate species contributing > 10% to between-site differences based on SIMPER analysis, with arrow length proportional to correlation strength. Clear spatial segregation demonstrates significant differences in community structure among sites (PERMANOVA: pseudo-F
2,
12 = 8.47,
p < 0.001, R
2 = 0.53). The ordination reveals that Site B assemblages are consistently distinct from Sites A and C, while the latter two show partial overlap, suggesting intermediate similarity in community composition (
Figure 6).
Non-metric multidimensional scaling (NMDS) ordination of fish assemblages based on Bray–Curtis dissimilarity (stress = 0.12). Each point represents a monthly sampling event. Ellipses show 95% confidence intervals around site centroids. Vector arrows indicate species contributing > 10% to community differentiation (SIMPER analysis). Clear spatial segregation indicates significant differences in community structure among sites (PERMANOVA: pseudo-F2,12 = 8.47, p < 0.001). Community Structure: PERMANOVA revealed significant differences among sites (F2,12 = 8.47, p < 0.001, R2 = 0.53). All pairwise comparisons were significant (p < 0.01, Bonferroni corrected). Diversity Patterns: Site C exhibited significantly higher Shannon diversity than Sites A and B (H = 12.3, p < 0.001). Species richness differed significantly among all sites (H = 28.7, p < 0.001). Morphometric Analysis: Significant inter-site body size variation detected in 4/5 target species. Effect sizes ranged from medium (η2 = 0.079) to large (η2 = 0.161), indicating ecologically meaningful differences in growth patterns.
Our findings demonstrate that traditional internal combustion engine motors (Site B) significantly reduce fish species richness, abundance, and body lengths compared to a control site (Site C), while eco-friendly motors (Site A) exhibit negligible effects. This aligns with acoustic disturbance theories, where high-frequency noise from traditional motors disrupts fish behavior, leading to avoidance and stunted growth [
83]. Non-parametric tests (e.g., Kruskal–Wallis) robustly captured these differences, accounting for non-normal data distributions common in ecological datasets [
84]. Multivariate approaches like NMDS and PERMANOVA further elucidated community-level shifts, with traditional motors driving dissimilarity, potentially via selective pressure on sensitive species such as
C. macrolepis.
The lack of impact from eco-friendly motors suggests they mitigate noise pollution, supporting transitions to sustainable boating practices [
85]. However, limitations include single-site replication; future studies should incorporate temporal replicates and acoustic measurements. Overall, these results advocate for eco-motor adoption in sensitive aquatic ecosystems to preserve biodiversity.
3.3. Underwater Monitoring of the Body Length of Target Fish
In this study, underwater imagery was analyzed to assess fish abundance and body length (
Figure 7). The results are visualized through box plots that show the total length distributions for four species with adequate sample sizes. Box plots showing total length distributions across sampling sites for four species with adequate sample sizes. Boxes represent interquartile ranges (25th–75th percentiles), horizontal lines indicate medians, whiskers extend to 1.5 × IQR, and outliers are shown as individual points. Different letters above boxes indicate significant differences (
p < 0.05, Kruskal–Wallis test with Bonferroni-corrected Dunn’s post hoc test for multi-site comparisons, Mann–Whitney U test for two-site comparisons). Sample sizes shown in parentheses below site labels. Site B data are absent for
G. erythrourus and
O. sp. due to insufficient captures (n < 5). The consistent pattern of reduced body sizes at Site B across multiple species provides convergent evidence for growth-limiting environmental conditions. Box plots showing total length distributions for four target species across sampling sites. Boxes show interquartile ranges, horizontal lines indicate medians, whiskers extend to 1.5 × IQR, and circles show outliers. Different letters above boxes indicate significant differences (
p < 0.05, Kruskal–Wallis with Bonferroni-corrected Dunn’s test). Sample sizes shown in parentheses. Site B data absent for
G. erythrourus and
O. sp. due to insufficient captures. Anthropogenic impacts and ecosystem resilience.
The spatial scale of variation observed in this study (<5 km) emphasizes the localized nature of anthropogenic impacts in coastal lagoon systems and highlights the importance of fine-scale habitat heterogeneity for maintaining regional biodiversity [
85]. The contrasting patterns between Sites A and C suggest that well-managed eco-tourism activities may be compatible with biodiversity conservation, providing a potential model for sustainable coastal zone management [
9,
86].
Site A’s intermediate diversity patterns may reflect the dual influences of tourism-related nutrient inputs and active management through eco-friendly motor restrictions. While boat traffic can alter sediment dynamics and introduce contaminants, the observed maintenance of high species richness (60 species) suggests that current management practices are effectively mitigating negative impacts [
87,
88]. The dominance structure at this site, characterized by high abundances of both native (
N. come,
C. macrolepis) and non-native (
O. sp.) species, indicates a transitional state that warrants continued monitoring. Field observations revealed that docks utilizing low-frequency, environmentally friendly motors harbored significantly richer fish assemblages, with fish abundance being 61% higher and mean body length 38% greater compared to docks using conventional motors (
Figure 8).
Our findings demonstrate that traditional internal combustion engine motors (Site ICE) significantly reduce fish species richness, abundance, and body lengths compared to a control site (Site Control), while eco-friendly motors (Site Eco) exhibit negligible effects. This aligns with acoustic disturbance theories, where high-frequency noise from traditional motors disrupts fish behavior, leading to avoidance and stunted growth [
83]. Non-parametric tests (e.g., Kruskal–Wallis) robustly captured these differences, accounting for non-normal data distributions common in ecological datasets [
84]. Multivariate approaches like NMDS and PERMANOVA further elucidated community-level shifts, with traditional motors driving dissimilarity, potentially via selective pressure on sensitive species such as
C. macrolepis.
The academic value of these observations advances Experience Hierarchy Theory by empirically validating its application to technology-mediated ecotourism, demonstrating how propulsion choices hierarchically influence behavioral outcomes. Practically, findings inform lagoon operators to prioritize electric motors in guided tours, potentially reducing ecological impacts like eutrophication from fuel leaks while enhancing tourist satisfaction and conservation advocacy. Policy implications include incentives for electric adoption in recreational fishing regulations, aligning with global sustainability goals. Future research could longitudinally assess actual behavioral changes post-tour and extend to diverse lagoon types to enhance generalizability.
Methodological strengths, including robust model fit (CFI = 0.956; RMSEA = 0.048) and bootstrapped mediation, address potential concerns on causality in cross-sectional data, though self-reported measures warrant caution against bias; objective emission monitoring in follow-ups would enhance generalizability across contexts.