Wild Stocks Research Articles

Predictors of outplanted marine bivalve survival in restoration: A review and synthesis

Abstract Global declines in marine shellfish have resulted in widespread efforts to restore populations. Previous research has predominantly focused on substrate‐limited rather than recruitment‐limited systems, yet given increased use of aquaculture‐produced stock to restore marine bivalves, there is a need to understand differences in the survival of hatchery‐produced and translocated wild stock. We conducted a systematic review and synthesis of studies that quantified the survival of outplanted marine bivalves. The systematic review identified 893 unique stocking events across 111 studies for 29 species across 10 families. Most research has occurred in temperate regions (73%), across four bivalve families (Ostreidae 37%, Pectinidae 20%, Veneridae 16% and Mytilidae 11%). More stockings have outplanted hatchery‐produced (66%) than translocated stock (34%). We conducted quantitative analyses for five species to determine how stock origin, size at outplant, outplant density, substrate co‐deployment, predator exclusion and time since outplant influences survival. Survival consistently decreased through time across all species. Substrate co‐deployment, stock origin and size at outplant did not influence survival, while predator exclusion and outplant density affected some species. Synthesis and applications. Our analyses broadly demonstrate variability in the survival of outplanted bivalves through time, however predicted survival was poor after 2 years (<3%). Generally low survival highlights difficulties associated with conducting scalable restoration in recruitment‐limited systems. Based on our findings, using hatchery‐produced stock, mitigating predation and outplanting epifaunal bivalves at high densities may increase survival probabilities when outplanting stock for restoration. Further exploration is needed to understand whether use of aquaculture‐produced stock results in similar ecosystem structure, function, and service provisioning to natural and restored shellfish reefs in recruitment‐limited systems.

Willingness to pay for farmed salmon: Balancing sustainability and safety perceptions

Given pressure on wild fish stocks, aquaculture has worked to develop farmed seafood markets. While farmed seafood should be more sustainable, consumers may lack confidence in its sustainability and may have food safety concerns. Using a sample of 266 seafood consumers in the US state of Maine, the study examined preferences for wild-caught and farmed salmon based on safety perceptions of the latter. Most preferred wild-caught, but this declined with lower food safety concerns. Additionally, willingness to pay for certified sustainably farmed versus non-certified farmed salmon was compared, revealing higher premiums with greater confidence in food safety. The industry should improve food safety perceptions and promote its benefits as a sustainable seafood source.

A review of the global use of fishmeal and fish oil and the Fish In:Fish Out metric.

Aquacultured carnivorous species consume most of the world's fishmeal and fish oil (FMFO), which itself is primarily derived from small pelagic fish. This has raised concerns about the practice's impact on wild fish stocks, ecosystems, and coastal communities that rely on these fish. The aquaculture industry claims a decreasing dependence on wild fish, relying on the Fish In:Fish Out (FIFO) metric as a ratio of the quantity of wild fish required for farmed fish production. This is misleading because it usually assumes constant FM or FO yields, inclusion rates and feed conversion ratios, which vary widely. Thus, a constant FIFO value for a given species cannot be assumed. Furthermore, low FIFO values resulting from averaging carnivores and herbivores conceal the high feed requirements of carnivore species. The increasing use of FMFO from by-products does not demonstrate a decreased use of wild fish but rather reflects a growing demand for FMFO, particularly for the fast growing and valuable salmon and shrimp farming industries.

Short-term tank culture of Gracilariopsis heteroclada at high salinities improves agar quality

Abstract Agar, a phycocolloid naturally extracted from Gracilariopsis heteroclada is strongly influenced by salinity. Wild stocks of G. heteroclada were exposed to varying salinities (20, 30, 40, 50, 60) for 6 days, and subsequently processed for agar extraction using 5 % NaOH. The extracted agar was evaluated regarding yield, gel rheology, colour composition, chemical properties, and infrared spectra. Results highlighted that hypersaline conditions (salinity 50) could produce high agar yield (4.77 %) and viscosity (10.67 mPa s), while agar samples at salinity 40 exhibited gels with high cohesiveness (6.35 mm), gel breaking strength (3.01 N), and gel strength (390.61 g cm−2) while having a rather high 3,6-anhydrogalactose content (7.49 %). All samples exhibited FTIR signature peaks at 930 cm−1, confirming the identity of extracted agar from G. heteroclada. Exposure at increasing hypersalinity increased the sulphate levels of agar from G. heteroclada, which implies synthesis of sulphated polysaccharides. Moreover, high 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities were obtained in acid hydrolysed agars at salinities of 40 (74.09 %) and 50 (75.57 %), suggesting that G. heteroclada agars from hypersaline conditions potentially offer antioxidative roles beyond its traditional food use.

Genetic Diversity Losses in Mantis Shrimp Oratosquilla oratoria Offspring Created for Supportive Releases Using an Ecological Breeding in Earthen Pond Method

ABSTRACTArtificial breeding of mantis shrimp Oratosquilla oratoria, using the ecological breeding in earthen pond (EBEP) method, has been carrying out from 2019, and the produced larvae have always been used for supportive breeding programs in Bohai Bay. To assess the degree of fidelity of enhancement programs used an EBEP method to native genetic pools, genetic diversity at 10 microsatellite loci was analyzed in three hatchery offspring populations, their wild parent stocks, and their wild contemporaneous offspring. Significant decrease in the almost genetic diversity parameters and highly significant differences in shannon's information index (decreasing by 22.54%–40.97%) and allelic richness (33.80%–46.87%) were observed between in hatchery populations. This further created relatively more genetic differentiation between the hatchery and wild population, as the pairwise Fst values and genetic distances showed. The mean pairwise relatedness coefficients showed higher values within hatchery populations and lower values within wild populations. Hatchery populations contained the fewest full‐sib families and offspring were extremely distributed in 10–11 full‐sib groups in each hatchery population. The relatively small number of actual spawning females and large variance in parental contribution to the next generation possibly causes allele reduction in the hatchery population, which in turn leads to a decrease in allelic diversity and an increase in genetic similarities among individuals. Promoting synchrony of ovarian development in females, providing good conditions for incubation and larvae culture and balancing the contributions of parents will be important in future breeding propagation.

Domesticating the wild through escapees of two iconic mediterranean farmed fish species

Extractive fisheries and marine aquaculture share space and target species. Several regional-scale examples exist of escapees entering wild fisheries landings, yet no study has assessed the influence of aquaculture on landings at an ecosystem scale. We examined the effects of farmed fish escapes on fisheries using FAO data and published escape rates for Gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax). Seabream landings were significantly correlated with the estimated biomass of escaped seabream entering the wild. There was a similar pattern for seabass until 2005, but the overall relationship between landings and escapes was not significant due to the dramatic drop in catches in recent years. We argue that seabass escapees’ relatively high mortality, lower capturability, and minor ‘leaking’ from farms may obscure their influence on landings. Significant positive fisheries regime shifts were detected for both species, matching the onset of aquaculture in the Mediterranean and the period when escapees from aquaculture surpassed landings. Our results suggest that fish escapes of these two iconic species may mask wild stock overexploitation, confound stock assessments, alter genetic diversity, increase the risk of spreading pathogens and parasites, and compete with wild conspecifics while boosting fisheries landings.

Stock status and spawning potential ratio of orange mud crab (Scylla olivacea, Herbst 1796) in the southwestern coastal waters of Bangladesh

Scylla olivacea (Orange mud crab) is a second commercial invertebrate species exported from Bangladesh. Though a significant portion of exports are supported by aquaculture, their farming ultimately depends on their wild stocks. Unfortunately, unregulated exploitation has led to a significant decline in the natural biomass of this species, raising concerns about the sustainability of crab production in Bangladesh. The study aimed to assess the stock status of S. olivacea (Orange mud crab) from the Southwestern coastal water of Bangladesh. One-year length frequency (width frequency-WF for crustacean fishery) data were collected and analyzed using the LBB (Length-based Bayesian Biomass) and LB-SPR (Length-based spawning potential ratio) methods. The assessed width parameter depicted the exploitation of small-size individuals (Wc=< Wc_opt) of S. olivacea. The estimated B/B0 (0.25) suggests that 75 % of the wild stock had already been harvested, and biomass cannot produce MSY. The mean estimates for SW50 % and SW95 % were 8.29 cm and 12.76 cm respectively, revealing the use of a small mesh-size net for crab harvesting. The assessed Spawning Potential Ratio (SPR) was 12 % which is below the SPR limit reference point (SRP) of 20 %. This research confirmed the overfished (F/M = 1.4) and overexploited (E = 0.58) status of S. olivacea in Bangladesh. To ensure the sustainability of coastal fisheries in Bangladesh, the authorities must take immediate management measures to control the overexploitation of this species.

Genetic analysis of village pear (Pyrus communis L.) cultivar populations in northeastern Türkiye

Abstract Pear (Pyrus communis L.) stands out as a prominent fruit species in temperate regions worldwide. The Çoruh River basin, nestled in the lower Caucasus in Türkiye, serves as a valuable repository of pear germplasm. To elucidate the genetic structure of pear populations in this region, 84 village pear cultivar genotypes (land races) from six villages, sample garden collections (SCC), and wild Panta root stock populations were analysed using eleven microsatellite markers. Genetic diversity and structure analyses indicated that village pear cultivar populations exhibit substantial genetic diversity and admixture. This diversity is attributed to local farming practices such as phenotypic selection and widespread dispersal of clonal materials. The genetic structure analysis, combined with the identification of private alleles, indicates that the pear genetic resources in the Çoruh river basin likely has originated from two gene pool sources, specifically the Meydancık and Camili village pear traditional cultivar populations. The Camili village pear cultivar population as a new in situ genetic reserve site has been proposed. Despite the existence an ex situ conservation site, the study suggests inadequateness of SCC as an ex situ site in capturing the full extent of genetic diversity of village pear cultivar genetic resources. Thus, enriching the genetic diversity in the SCC ex situ site is essential for effective pear genetic resource conservation in the Çoruh river basin. These findings contribute valuable insights for the development of targeted conservation strategies, ensuring the preservation of pear genetic resources in this region.

Swimming performance, but not metabolism, is related to a boldness-activity syndrome in schoolmaster snapper (Lutjanus apodus).

Commercial overexploitation and climate change can alter the physiology and behavior of marine organisms, although intraspecific phenotypic responses to such changes can vary greatly depending on the environment, species, and severity of the stressor. Under the pace-of-life syndrome (POLS) hypothesis, behavior, physiology, and life-history traits are linked, and thus, affected by selection targeting any aspect of organismal biology. However, these links are understudied in tropical marine fishes, and further work is needed to better understand the impacts of fisheries and climate change on wild stocks. Moreover, tropical regions have a greater reliance on fisheries; thus investigations should focus on species with substantial socioeconomic value to ensure benefits at the local level. This study aimed to address this need by measuring the behavior (boldness and activity), metabolism, and swimming performance (using a critical swim speed [Ucrit] test) of schoolmaster snapper Lutjanus apodus in Eleuthera, the Bahamas. We report a strong positive correlation between boldness and activity, high repeatability of these behavioral metrics, and two groupings that were consistent with "proactive" and "reactive" behavioral types. These behavioral types differed significantly in their swimming performance, with reactive individuals having a 13.1% higher mean Ucrit. In contrast, no significant differences were found in the measured metabolic parameters between behavioral types. This study is the first to investigate the intraspecific links between behavior and physiology in a snapper species, using the novel and ecologically relevant comparison of Ucrit with behavioral syndrome types. These data suggest that additional research is needed to better predict the success of proactive/reactive tropical fish if overexploited and as influenced by climate change.

WSETO: wild stock exchange trading optimization algorithm enabled routing for NB-IoT tracking system

WSETO: wild stock exchange trading optimization algorithm enabled routing for NB-IoT tracking system

Phylogenetic, growth performance and protein growth hormone of snakehead fish (Channa striata) from wild stock in Sumatra, Indonesia

Abstract Watershed isolation may influence morphological, genetic variations, and protein expression of snakehead fish (Channa striata). This research seeks to identify snakehead diversity from isolated Inland waters in Sumatra, i.e., Kampar River (SK), Merang River (SM), Cala Lake (DC), and Lampam Floodplain (RL). Channa striata samples were collected from inland waters and cultivated in Aquaculture laboratory. Cytochrome b gene was used for genetic characterization. Growth protein was analyzed using Enzyme-Linked Immunosorbent Assays (ELISA). We collected DNA from four samples at each site. The growth performance of cultivated snakehead fish was also observed. Five hundred post-juvenile snakehead fish from four populations were cultivated for 45-days with five repetitions. Each population had 12 snakehead fish tested for GH protein. Data were statistically tested using ANOVA, maximum likelihood phylogenetic tree analysis, linear regression, and Pearson correlation. The results showed four clusters of snakehead fish in the phylogenetic tree. The DC population had the highest significant value of the daily length growth rate (7.5±0.2 %). The GH protein-growth relationship was low (0.014-0.083). The SM snakehead fish population had the highest concentration of GH protein (1.77±0.11 pg μl−1) and had distinct cyt.b gene clusters from other populations, making it a potential candidate for future aquaculture strain development.

Spatial and Seasonal Variations in the Size-Weight Relationship and Condition Index of the Mangrove Oyster Crassostrea tulipa (Lamarck, 1819) in the Saloum Delta, Senegal

In the Saloum delta in Senegal, the mangrove oyster Crassostrea tulipa is under increasing human pressure, leading to a decline in wild stocks, a decrease in the quality of the marketed oysters and the degradation of mangrove tree roots. Previous studies have pinpointed some of these disturbances and yet, there is little information available on the structure of the population and the condition index of the species. The aim of this study was to document these aspects in order to support a sustainable management of the resource. From January 2021 to December 2022, monthly sampling was carried out at five stations to study the size-weight relationship and the condition index (CI) of oysters. A total of 26,790 individuals ranging in size from 0.23 to 93.19 mm with an average of 33.86±16.38 mm shell height were collected. The species was found to have a minority allometry (b = 2.54 &lt;3), with a strong correlation between individual weight and oyster shell height (r = 0.88). CI showed seasonal and inter-site variations over the two years, with an overall mean value of 11.17±2.72%. The highest CI values were observed during the hot season and the lowest during the hot-cold transition period.

Resource Availability and Use in Restored, Unmanaged, and Aquaculture Mangrove Ecosystems in Indonesia

Mangrove ecosystems are some of the most productive on our planet but have declined globally by 30–50%. Many species rely on mangrove habitats; thus, their conversion to aquaculture farms has led to noticeable losses in commodities such as wild fish stocks. This study aimed to assess the influence of aquaculture and restoration projects on the ecosystem’s ability to provide resources. We collected data on mangrove vegetation (i.e., biomass, richness, and abundance), soil nutrients (i.e., organic carbon, aluminium, and nitrogen), crab abundance, and fishing pressure at six sites. We set up 15 plots at each site and collected data between May and July 2023. Via generalised linear mixed models, we found that the abundance and richness of crabs was significantly higher in aquaculture plots than in non-aquaculture plots. Aquaculture plots had higher topsoil aluminium, higher topsoil and subsoil nitrogen, and lower topsoil carbon than non-aquaculture sites. Restored sites had less nitrogen in the topsoil than unmanaged sites. The biomass did not change between aquaculture, restored, and unmanaged plots. We found a negative correlation between crab abundance and richness and mangrove diameter at breast height (DBH), suggesting that the species of crabs present preferred areas with propagules for feeding (e.g., Grapsidae crabs). The content of nitrogen in the subsoil was positively correlated with mangrove richness, diversity, and height, suggesting the importance of nitrogen availability for mangrove growth. The content of aluminium in the subsoil was negatively correlated with the content of organic carbon in both the topsoil and subsoil, suggesting the detrimental effect of aluminium on the carbon cycle. Fishing practices were observed at all sites during the data collection period. Despite the lack of significant impact on most vegetation parameters and the limited differences between managed and unmanaged sites, key variables such as soil aluminium, carbon, and nitrogen contents and crab assemblages exhibited high variability, highlighting the complex interactions within mangrove ecosystems.

Genetic diversity of the Ruditapes decussatus and evidence of its hybridization with the alien R. philippinarum in the Western Mediterranean Sea

The introduction of alien species in marine ecosystems is often driven by the increasing demand of fishery resources. This is the case of the Manila clam (R. philippinarum), imported in Europe from Japan since the 1970s, to meet the growing demand for clams that the native species, the grooved carpet shell clam (Ruditapes decussatus), could not satisfy. Alien species introduction could threaten the genetic diversity and integrity of the native clam, also causing hybridization (i.e., gene flow from one species into the gene pool of another). Since R. philippinarum recently spread in a few important Mediterranean coastal areas, a combined approach based on morphological characteristics, length differences of two nuclear species-specific markers (ITS2, 5SrDNA) and the sequence of the mitochondrial gene cytochrome c oxidase subunit I (COI), was used to investigate the presence of hybrids in six Mediterranean wetlands (Sardinia, Italy). Eight individuals morphologically identified as R. decussatus were hybrids, having sequences specific to both R. decussatus and R. philippinarum in their nuclear DNA (ITS2 and 5SrDNA). Most of these individuals were found to be post-first generation (F1) hybrids indicating that F1-hybrids may be fertile. Secondly, to study the genetic diversity of R. decussatus in the Sardinian wetlands as well as in its whole distribution area, >380 new COI sequences from the eastern Atlantic Ocean and Mediterranean Sea were analysed along with those available from public databases. Mitochondrial COI data revealed variable haplotype and nucleotide diversities in different areas, which were not dependent on sample sizes. The aquaculture breeding activities and clam transplantation between different countries, along with the long pelagic larval dispersal and the commercial import of other bivalve species might have promoted gene exchange between different sites and thus higher diversity levels in a few wild populations. Our research, evaluating the genetic makeup of wild and hatchery stocks and clarifying the degree of hybridization, can contribute to develop further recommendations for conserving the genetic integrity of R. decussatus.

Thermal performance of native and invasive crab species: investigating the invasion potential of Hemigrapsus takanoi in southern European Carcinus maenas’ habitats

Invasive species’ plasticity and latitudinal spread have become an increasing matter of concern in rapidly changing climate. The brush-clawed shore crab (Hemigrapsus takanoi), native along northwestern Pacific shores, has established dense populations in northern European coasts. Detrimental effects in natura have been reported, such as displacement of native species and competition for shelter, rasing concerns regarding shellfish early life stages and food webs-posing a threat to wild stocks’ recruitment and aquaculture. The species has not yet been observed in southern European countries (e.g., Portugal), where niche habitats such as harbours, mudflats, and lagoons reach higher temperatures than the invaded northern range. The aims of this study were to determine H. takanoi potential to acclimate to a southern thermal range, assess thermal performance, and identify potential competitive advantages over the native shore crab Carcinus maenas. This was accomplished through individual exposure to one of three treatments, resembling a southern European thermal range (17 °C, 21 °C, or 25 °C), for 30 days. H. takanoi thrived in temperatures as high as 25 °C, a realistic thermal scenario in Óbidos Lagoon (the biggest Portuguese lagoon)—while the native shore crab C. maenas underperformed at that treatment, showing lower survival, growth, and feed intake than H. takanoi. These results suggest that H. takanoi may be able to colonise southern and warmer European locations and have higher plasticity than the native species already inhabiting areas close to its upper thermal limits. Under global warming scenarios, inferences of further latitudinal spread and increased invaded range may also be taken to the invaded northern European habitats.

The first phycopathological atlas in Latin America unveils the underdocumentation of algal pathogens

To date, the biodiversity of disease-causing agents in algae has been poorly investigated. This information however is particularly relevant, as outbreaks are repeatedly reported in mariculture facilities or commercial wild stocks, with no available baselines to compare with. Algal pathogens identified in Latin America are few; information is scattered and mostly unknown for regional aquacultural actors such as farmers, seaweed gatherers, conservation biologists and policymakers. In this work, we reviewed all the pathogens described for algae in Latin America, including their taxonomy, macro and microscopic symptoms, aetiology, habitat and reported distribution in this region. Furthermore, we included new records obtained in 2020–2022 in the Southeastern Pacific, and the results of a screen for viruses on kelp gametophytes from a regional germplasm including south Pacific and Atlantic strains. Only nine countries have described algal pathogens so far. The Southeast Pacific (Chilean coast) concentrates the largest number of records and correspond to endophytic algae of different taxa (34 %), viruses (21 %) and protistan pseudofungi (20 %). In our 2020–2022 sampling campaigns, 33 new records were reported for Latin America, which constitutes 15 % of the total records for the region. Overall, unbalanced track records were detected at geographical (e.g. country), temporal (year), diagnosis type and outbreak level, possibly due to scattered and unsystematic sampling efforts. Our results show that pathogens remain cryptic threats for seaweed-related human activities. We anticipate that as the sampling effort increases, algal pathogen records will also increase in number and importance, in proportions comparable to other ecologically and commercially relevant aquatic resources.

Navigating aquaculture losses: Tackling fish‐killing phytoflagellates in a changing global landscape

AbstractAquaculture has emerged as a pivotal alternative for seafood production, addressing the challenges posed by depleting wild fish stocks. However, the industry faces substantial challenges, notably the presence of harmful algal blooms (HABs), which can cause serious economic consequences. The proliferation of major species of phytoflagellates leading to massive fish mortality is on the rise, possibly attributed to increasing global temperatures and eutrophication. This underscores the critical need for robust detection, prevention, and mitigation strategies to safeguard the aquaculture industry. This contribution offers valuable insights into comprehending and addressing the challenges posed by HABs in the fish aquaculture sector in an era of global change.

Ovarian histology of the freshwater catfish Silonia silondia (Hamilton, 1822)

Histological characterization of gonadal tissues and their development can divulge vital clues to interpret the onset and progression of the spawning period in fish species and help in wild stock augmentation to conserve the natural fish stocks. In the present study, ovarian histology of female Silonia silonda was investigated from the Kangsha River, Bangladesh from March to November 2018. During this investigation, 54 females of Silonia silondia was analyzed to study the ovarian development. The histological evaluation revealed five distinct stages of gonadal development (Immature, Developing, Spawning capable, Regression or spent and Regeneration or Re-developing). Six phases of oocyte development were further characterized during the gonadal development stages as under-developed, primary growth, cortical alveolar, vitellogenic, pre-mature, and mature stage. In conclusion, the gonado-somatic index and histological analysis of ovaries indicated that the peak spawning of S. silondia occurs in July, and suggesting that the studied fish spawns once per breeding season. The present study recommends year round investigation of gonadal cycle and gonad developmental study of male individuals of S. silonida.

Negative association of sea lice from fish farms on recreational fishing catches of Atlantic salmon

Abstract The question of whether and to what extent sea‐louse (Lepeophtheirus salmonis) infestations from salmon farms influence wild Atlantic salmon survival has been subject to sustained scientific debate and political controversy. Documenting population‐level effects of sea lice on wild salmon remains inherently challenging. We employ comprehensive sea‐lice data and recreational catch data from Norway to assess the impact of farm sea‐louse infestations on wild salmon catches in different production areas (PAs). Our analysis finds a significant correlation between declines in wild Atlantic salmon catches and increasing amounts of adult female sea lice per km2. The effect is most pronounced in PA 4 on the west coast of Norway, an area within the government's” traffic light” management system where out‐migrating salmon smolts are deemed to face high risk of louse‐induced mortality. Our model predicts below‐average catches when the total sea‐louse load exceeds the limit of 0.1 average adult female sea louse per farmed fish within some production areas. Furthermore, our results indicate that the risk of below‐average catches increases by approximately 47% when salmon farms exceed this limit (estimated risk ratio of 1.47, 95% CI [1.10, 1.96]). Synthesis and applications: Our study expands the existing body of evidence demonstrating a negative association between fish farming and the ecosystem services provided by wild salmon stocks. This has important implications for aquaculture management. First, it shows that farm sea lice directly affect peoples, rights holders and interest groups, such as landowners and anglers, who rely on viable populations of wild salmon. Second, it suggests that a &gt;0.1 sea lice limit may be insufficient to prevent subpar catches in some areas. Furthermore, in the context of allowing further growth in farmed salmon biomass, setting absolute sea‐louse limits for entire production areas may be a more effective regulatory instrument than setting average lice limits per farmed fish. Our findings contribute to advancing a scientific basis for setting appropriate louse limits on farm and area scales.

Movement Behavior of the Dusky Grouper Epinephelus marginatus (Lowe, 1834) in Early Life Stages

The dusky grouper (Epinephelus marginatus) is a vulnerable predatory fish found in the Atlantic and Indian oceans, and in the Mediterranean Sea. This study investigates the movement patterns of grouper larvae (151 individuals) during their first feeding period (three to ten days post hatching) through laboratory experiments offering rotifers (Brachionus sp.) and copepod nauplii as food. High-speed cameras and imaging techniques including bright field microscopy, matched filters, and holography captured rapid displacements (up to 25 body lengths per second), peduncle caudal beats (up to 40 beats s−1), turns, and resting periods. Reynolds numbers ranged from &lt;45 for routine swimming to 222 for burst swimming. Specific behaviors, including changes in swimming velocity and body movements, were observed from three days post hatching, when feeding begins, suggestive of an array of responses to environmental forcing, predator avoidance, food search, and feeding success. These findings provide insights into the critical movement performances of E. marginatus larvae, which help to unravel their ecological interactions and survival strategies. Understanding grouper larval swimming behavior is pivotal for devising effective cultivation strategies aimed at replenishing wild stocks and enhancing production for human consumption.