Snapper Species Research Articles

Otolith growth chronologies reveal distinct environmental sensitivities between and within shallow- and deep-water snappers

AbstractFish growth underpins individual fitness and population-level metrics, with fluctuations linked to environmental variability. Growth chronologies derived from otolith increment analysis are a powerful proxy to understand population responses to environmental change and productivity. Yet, long-term patterns of growth and their environmental drivers are better understood for shallow-water species compared to deep-water inhabitants. Additionally, focus is largely on adults, disregarding the potential influence of juvenile growth which is critical to size- and age-at-maturity. Here, we investigate the long-term growth patterns of two commercially important snapper species separated by depth in northwestern Australia’s coastal shelf waters, the shallow-water Lutjanus sebae (70 year chronology, 1950–2020) and the deep-water Etelis boweni (41 year chronology, 1973–2013). Annually-resolved otolith growth chronologies revealed distinct environmental sensitivities within (juveniles vs adults) and among (shallow- vs deep-water habitats) species. Within species, juveniles and adults responded differently to shared environmental stimuli, highlighting the importance of understanding the impacts of environmental effects and sensitivities for different life-history stages. Across species, L. sebae exhibited highly variable growth tied to local climate signals such as sea surface temperature and rainfall, while E. boweni displayed more stable growth patterns that only responded to interannual and decadal shifts in the environment (e.g. Pacific Decadal Oscillation). Our results highlight potential vulnerabilities of shallow-water species to future environmental perturbations compared to species residing at depth, as they are likely to encounter more extreme climate variability under future oceanic conditions. This study contributes valuable insights into understanding and managing the impacts of future environmental variability on fisheries sustainability, emphasising the need for continued research across species and habitats.

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.

Length-Weight relationship and condition factor of Lutjanus peru and L. guttatus from the Gulf of California Mexico.

Fulton’s condition factor (k) and the length-weight relationship (LWR) are the most important biological tools with respect to basic aspects of fish population dynamics; they are applicable to strategic plans for the conservation and management of fisheries. A total of 478 snappers Lutjanus peru and L. guttatus were analyzed in Santa Rosalía, Baja California Sur, in the Gulf of California. The total length of Lutjanus peru ranged from 21 to 55 cm, and weight ranged from 215 to 1,920 g, whereas total length of L. guttatus ranged from 21 to 59 cm, and weight ranged from 290 to 1,675 g. The LWR and condition factor were estimated for the two species and intraspecific factors were analyzed (sex, season, maturity stage) using Bayesian hierarchical models with random effects. The parameters of the LWR equation were similar for the two snapper species (α≈0.026 and β ≈ 2.8); they both presented negative allometric growth (p(β<3)>85%). The L. peru growth rate was greater in the warm season (p(βwarm>βcold)≈97%), whereas this difference was not as evident in L. guttatus (p(βwarm<βcold)≈72%). The condition factor k was greater than 1 for all categories in the two species (p(μk)=100%), which suggests that they keep a good body condition. This indicates that L. peru and L. guttatus in Santa Rosalía experience environmental conditions that benefit their body condition, as a function of year-round food availability. This information is useful for future conservation studies and for monitoring snapper captures, as most L. peru individuals caught were sexually immature.

An empirical DNA-based identification of morphologically similar snappers (Lutjanus campechanus, Lutjanus purpureus) using a versatile bioinformatics workflow for the discovery and analysis of informative single-nucleotide polymorphisms

The commercially important species Lutjanus campechanus (Northern/Gulf red snapper) and Lutjanus purpureus (Southern/Caribbean red snapper) are the protagonists of a decade’s long taxonomic debate over their species delimitation, due in part to partial habitat overlap, extensive morphological similarity, and the lack of resolution when applying canonically reliable DNA barcoding approaches. In this study, we leveraged publicly available RAD-Seq data for L. campechanus and L. purpureus to identify species-informative single‐nucleotide polymorphisms (SNPs) at the genome scale that were successful in distinguishing the Northern and Southern red snappers, while also detecting individuals exhibiting introgression. This 4-step empirical approach demonstrates the value of applying novel bioinformatics pipelines to existing genome-scale data to maximize the distillation of informative subsets. Our results facilitate economically relevant species identification in addition to confirming or challenging species identifications for specimens with data in public databases. These findings and their applications will benefit future sustainability strategies and broader research questions surrounding these overfished and evolutionarily entangled snapper species.

Trophic position and prey preferences of snappers (Teleostei: Lutjanidae) in a connected bay-to-reef Caribbean system

The trophic position (TP) and proportional contribution of prey for six species of snappers were assessed at two interconnected coastal environments of the Mexican Caribbean: the mangroves of Río Huach Channel and Chetumal/Corozal Bay, and the seagrass beds of the adjacent Xcalak Reef Lagoon. This study provides a trophic scenario using stable isotopes, under the hypothesis that use of resources would vary by habitat. We evaluated the relative proportion of carbon and nitrogen of assimilated resources and TP. According to the stable isotope mixing models, snappers showed a higher consumption of secondary consumers at the expense of primary consumers. Snappers are piscivorous-invertivorous mesopredators and the most piscivorous species were Lutjanus griseus and L. jocu, which displayed a higher TP. Lutjanus griseus had a higher TP than the other snappers both in the bay and the reef lagoon, whereas Ocyurus chrysurus showed the lowest TP, with a major preference for crustaceans. Our findings revealed differences in resource use by snapper species rather than by habitat. Understanding TP and differential use of resources by snappers is key to understanding the dynamics and function of connected ecosystems to implement effective conservation and management strategies.

Daily age, growth rate, and pelagic larval duration of commercially important snapper species in Abrolhos National Marine Park.

The age and daily growth of fish are registered through the deposition of increments in their otoliths, which are concretions formed by the precipitation of substances present in the endolymphatic fluid, mainly calcium carbonate (CaCO3). Faced with the need to fill some of the gaps in the knowledge on the occurrence and duration of the initial stages of snapper species' life cycles in the Abrolhos Bank, this study aimed to describe the growth rates, age, and period of pelagic larval duration (PLD) of three snapper species during the larval pre-settlement phase, in the Abrolhos Bank region. The post-larvae were captured using light traps. Otoliths were removed from 117 samples of snapper species; however, only 69 were viable for age estimation, of which 15 were Lutjanus analis, 25 were Lutjanus jocu, and 29 were Lutjanus synagris. Together, the samples presented individuals with total lengths ranging from 16.14 to 24.76 mm and ages from 21 to 39 days. Settlement marks were found for all three species, and the average PLD was ~25 days. The somatic growth of the snapper species was positively correlated with otolith growth. L. jocu presented the greatest daily growth compared to the other species. The three species use the Abrolhos Bank as a larval settlement site, demonstrating plasticity by using different habitats throughout their lives.

Abudance of demersal fish by longline fishing gear in Sentang Waters, Serdang Bedagai Regency, Sumatera Utara

Demersal fish is the main catch for traditional fishermen using longline fishing gear in Sentang Beach waters located in Serdang Bedagai Regency, North Sumatra Province. The high economic value of demersal fish is the focus of traditional fishermen to make it the main catch. This study aims to determine the composition of the catch and the abundance index of demersal fish caught by longline in the waters of Sentang Beach. The method used in this research is to use a random sampling method with the mechanism of joining fishermen to go to sea for one month every time fishermen go to sea in November 2022. The data analysis technique uses abundance index value analysis and multiple linear regression analysis. The results showed that the composition of demersal fish caught using longline fishing gear consisted of 5 species of fish namely Snapper (Lates calcarife), Threadfins (Eleutheronema tetradactylum), Pomfret (Pampus argenteus), Sagor catfish (Hexanematichthys sagor) and Mullet (Valamugil saheli) with the highest abundance index obtained by the mullet species. Obtained the highest relative relative abudance of fish found in Senangin species which is 100% and the lowest relative relative abudance of fish in the species of Snapper which is 1.14%.

Recruitment of Juvenile Snapper (Lutjanidae) in the Middle Florida Keys: Temporal Trends and Fine-Scale Habitat Associations

Juvenile recruitment is a major factor in the establishment and maintenance of local population structures of coral reef fishes. An understanding of the factors that affect juvenile recruitment and survival help explain spatial and temporal patterns in adult abundance, especially of commercially and recreationally fished species. Here, we examined the distribution and juvenile recruitment of 5 snapper species: Mutton Snapper (Lutjanus analis), Lane Snapper (L. synagris), Schoolmaster (L. apodus), Gray Snapper (L. griseus), and Yellowtail Snapper (Ocyurus chrysurus) collected in 1,314 seine samples conducted between 2007 and 2019 in the Middle Florida Keys. We use a generalized linear modeling routine to assess juvenile recruitment of each species as a function of temporal, environmental, and benthic habitat variables. Interannual variability in juvenile recruitment ranged between 2 and 15—fold differences in mean predicted abundance between the highest and lowest producing years by species. Predicted recruitment varied dramatically by species in 2010 following a historic cold spell in south Florida. Three of the 5 species (Lane Snapper, Yellowtail Snapper, and Schoolmaster) exhibited the lowest observed yearly recruitment in that year, while Gray Snapper recruitment peaked. For all species, recruitment indices exhibited strong seasonal trends with peak abundances observed in the fall. Aquatic vegetation type, aquatic vegetation cover, distance from shore, and water temperature were the most important predictors of abundance. Results of this study highlight species—specific preferences for settlement habitat, demonstrate the importance of local—scale recruitment processes, and provide updated, management—relevant juvenile abundance indices for shallow water snapper in the Middle Florida Keys.

Rapid RNase H-dependent PCR lateral flow assay for the detection of red snapper

Red snapper (Lutjanus campechanus or Lutjanus purpureus) is one of the most commercially important and commonly mislabeled seafood species in the United States. Existing molecular methods for species identification are expensive and require being sent to an off-site laboratory, which takes multiple days to process. In this study, we have standardized a rapid rhPCR-coupled lateral flow assay for the identification of red snapper species. Our assay involved a simple heat-lysis DNA extraction procedure and a multiplex PCR reaction, consisting of a red snapper single nucleotide polymorphism (SNP)-specific rhPCR primer, thermotolerant RNase H2 enzyme, and an internal amplification control (IAC) for their onsite identification. Amplicons generated in the PCR reaction were detected using dual target lateral flow strips. The standardized assay was validated with 108 barcoded fish samples. Samples identified as Lutjanus campechanus or L. purpureus by DNA barcoding formed three distinct bands, while other fish species formed only two bands on the lateral flow strips. A minimum of 0.37 ng of crude DNA was detectable in the rhPCR reaction and generated a visible band on the lateral flow dipstick. The assay showed 100% specificity and took 90–120 min to complete. The assay generated results that can be used to authenticate red snapper at the wholesale and retail levels of seafood processing and commerce. Our results confirm the ability of rhPCR-lateral flow assays to be an alternative tool for onsite species authentication for the seafood industry.

Detection and identification of Red Snapper (Lutjanus gibbus and Lutjanus malabaricus) and grouper (Plectropomus leopardus and Plectropomus maculatus) with deep learning

The Indonesian fishing industry is a major global contributor, particularly in the production and export of snapper and grouper fish. These two groups of fish are known for their high diversity, but distinguishing between the different species can be challenging due to their morphological similarities. In order to overcome this challenge, this paper proposes the application of deep learning methods to identify the two major species of snapper and grouper accurately. The deep learning framework utilized in this study is Detectron2, a state-of-the-art object detection and segmentation model. The datasets used in the study consist of 500 images each for the snapper species Lutjanus gibbus and Lutjanus malabaricus, and the grouper species Plectropomus leopardus and Plectropomus maculatus, totaling 2000 images. The datasets were labeled using Coco Annotator software with a focus on species segmentation. The labeled datasets were then trained using Google Collaboratory, resulting in an accuracy value of 89.51%, a precision of 87.69%, a recall of 99.85%, and an F1-score of 93.38%. These results demonstrate that, even with a relatively limited number of datasets, it is possible to accurately identify the Red Snapper Lutjanus gibbus and Lutjanus malabaricus, as well as the grouper species Plectropomus leopardus and Plectropomus maculatus using deep learning methods. In conclusion, this paper demonstrates the potential of deep learning methods, specifically Detectron2, in accurately identifying snapper and grouper species. The results of this study suggest that this technology can be used to improve the accuracy and efficiency of fish species identification, which could have significant implications for the fishing industry and marine conservation efforts.

Spawning aggregations of checkered snapper (Lutjanus decussatus) and blackspot snapper (L. fulviflamma): seasonality, lunar-phase periodicity and spatial distribution within spawning ground.

Snappers (family Lutjanidae) are important fisheries target species and some species are known to form spawning aggregations at particular spawning grounds. The present study investigated the ecological characteristics of fish aggregations of two snapper species (checkered snapper Lutjanus decussatus and blackspot snapper L. fulviflamma) that form at a particular site. Specifically, the aims were to clarify (1) seasonality and lunar-phase periodicity of fish aggregation formation, (2) fine-scale spatial distribution of fish density (spatial variations of fish density at intervals of several-tens meters) within the aggregation site, (3) size and age frequency distributions of fishes in the aggregation site, (4) gonad development, (5) to compare fish abundance between inside and outside the aggregation site, and (6) to verify that fish aggregations of the two snapper species were spawning aggregation. Underwater observations using a 600m×5m transect revealed that greater fish abundance of Lutjanus decussatus was found monthly between May and October, and clear positive peaks in the fish abundance were found only around the last-quarter moon. This lunar-related periodicity in the increase of fish abundance was confirmed by a time-series analysis (correlogram). Within the aggregation site, L. decussatus showed a relatively uniform distribution. In contrast, greater fish abundance of L. fulviflamma was found monthly between April and October, and clear positive peaks in the fish abundance were found around the last-quarter moon (April, May, June and October) or new moon (July, August and September). This lunar-related periodicity was also confirmed by correlogram. Lutjanus fulviflamma showed a relatively clumped distribution within the aggregation site. Most females of the two species in the aggregation site had hydrated eggs, indicating that the two species form aggregations for reproduction. The two species, although occurring simultaneously, are considered to form aggregations of conspecifics only. For L. decussatus, average fork length and age of males and females were 229.2 mm and 243.9 mm and 9.4 years and 8.1 years, respectively. For L. fulviflamma, average fork length and age of males and females were 233.9 mm and 246.9 mm and 6.8 years and 8.1 years, respectively. Fish abundance inside the aggregation site was 266.8-fold and 141557.1-fold greater than those outside the aggregation site for L. decussatus and L. fulviflamma, respectively. These results showed that (1) fish aggregation formation of the two snapper species was predictably repeated in particular months and lunar-phase, (2) it was predictably found at the particular site, (3) the fish abundance in the aggregation site markedly exceeded the fish abundance outside the aggregation site, and (4) the two species form aggregations for reproduction. Therefore, it is suggested that the fish aggregations for the two species can be regarded as spawning aggregations.

Diet variability of snappers (Teleostei: Lutjanidae) in a bay-to-reef ecosystem of the Mexican Caribbean

Fishes use environmental resources differently. Snapper ontogenic movements among coastal habitats lead to diverse diets. We investigated the diets of seven snapper species (Lutjanus apodus, L. analis, L. griseus, L. jocu, L. mahogoni, L. synagris, and Ocyurus chrysurus) in three interconnected coastal environments in the western Caribbean: Río Huach channel, Chetumal/Corozal bay, and the adjacent Xcalak reef lagoon. These three encompass all habitats used by the seven species in the study area. Snapper diets were mostly composed of fish and crustaceans, but dominance of either group varied among the studied habitats; for example, fish were the main prey for L. apodus from the reef lagoon zone, but second in the bay. Snappers are piscivorous-invertivorous mesopredators; the species that relied the most on fishes were L. griseus and L. jocu, whereas O. chrysurus preferred crustaceans. Stomach content results revealed a high degree of dietary overlap among species. Our findings suggested a tradeoff in relative weight between fish and crustaceans as the main food source of snappers at these connected areas, supporting the hypothesis of niche segregation. Our results can be used as a baseline to further our understanding of the ecology and differences in resource use by snapper species in an area undergoing important anthropogenic changes.

A comparative analysis of osteocranium morphology in Lutjanus johnii (Bloch, 1792) and Lutjanus gibbus (Forsskal, 1775) inhabiting different habitats

The snapper species Lutjanus gibbus (L. gibbus) is commonly found in coastal areas characterized by coral reefs and clear water, while Lutjanus johnii (L. johnii) resides in mangrove waters with murky conditions and strong currents. The habitat plays a crucial role in influencing body shape and ossification patterns in fish. Therefore, this study aimed to examine the differences in the cranial bone morphology between the two Lutjanus fish species that resided in contrasting habitats. The fish samples were collected from local fishermen operating in the waters of Pulo Aceh, Aceh Besar, Indonesia. Following capture, the fish were transported and landed at Lampulo Fishing Port in Banda Aceh for further analysis. For each species, a total of 5 fish samples were randomly selected, and thorough cleaning of scales and muscles was performed before the drying of the bones. These dried cranial bones were then photographed, edited, and subjected to detailed analysis. The study showed that, of the 23 observed skull bone characters, 15 characters showed the differences in the cranial bones of the two snapper species, including the pre-ethmoidal, ethmoidal lateralis, prefrontal, supraorbital, nasal, ethmoidal, sphenoticum, crista occipital, lacrimal, inter-opercular, opercular, preopercular premaxilla, endopterygoideum, and hyomandibular. Significant differences were observed in the bones composing the eyes, nose, jaws, and ventral region of the head. In the mangrove snapper (L. johnii), the bones associated with the eyes (orbitospenoidal, supraorbital, and prefrontal) were less developed, while those related to the nose (nasal, ethmoidal, ethmoidal lateralis, pre-ethmoidal) showed well-developed characteristics. The coral snapper L. gibbus displayed a relatively small but thicker premaxilla bone in the jaw region, along with smaller bones in the ventral head area.Keywords:OsteologyMorphologyEcomorphologyOsteocraniumMaxillare

Handling Effects on Histological Identification of Female Reproductive Status: Examples from Tropical Deepwater Snappers

Post-mortem ovarian tissue degradation from handling effects, such as delays in preservation, can lead to inaccurate reproductive assessments. Therefore, it is important to understand the differences between handling effects and natural ovarian atresia. Seven treatments of various holding temperatures and times to preservation were applied to whole fish and extracted ovaries of three tropical deepwater snapper species. Ovarian post-mortem degradation was observed at 12 h at ambient temperature and after 48 h iced or refrigerated for both whole fish and extracted ovaries; however, degradation did not adversely affect correct reproductive phase classification in fishes stored in ice from 12 to 48 h post-capture. A clear histological indicator of post-mortem degradation was the breakdown of ooplasm organelles at the oocyte periphery observed in vitellogenic and cortical alveolar oocytes. However, the chorion typically remains intact during post-mortem degradation, in contrast to natural atresia. Effects on post-ovulatory follicles were most discernible after 96 h on ice or refrigeration. Freezing gonadal tissue resulted in drastic changes to oocyte shape and morphology, making reproductive phase classification challenging. We advise that (1) freezing ovaries should be avoided where possible, and (2) gonad tissue should ideally be preserved immediately but no later than 48 h post-capture.

Using multi-model inference to determine the growth rates of red snapper, Lutjanus campechanus, through ontogeny

Growth rates of a single cohort of F1, captive-reared red snapper, Lutjanus campechanus, were determined through ontogeny using a multi-model inference approach. Water temperature averaged 23.6 ± 0.13 °C based on the ambient conditions of the study location in Miami, Florida. Growth rates in length-at-age and weight-at-age were best expressed using the von Bertalanffy model with the equations Lt = 742.6 (1 – e0.001804(a-31.57)) and Wt = 84720 (1 – e-0.0005787(a+78.71))3.304, respectively. The length-weight relationship was expressed by the equation W = 0.000003158 (Lt3.304). Red snapper grew to market-based harvest sizes of 450 g and 750 g by 318 (SGR = 1.403%/day) and 393 (SGR = 1.2%/day) days post hatch, respectively. Size at age was markedly higher than those reported in age-class studies for captive-reared red snapper and in the available wild-capture data for the species. Feed conversion ratios (1.32, cumulatively) generated in this study were commensurate with or lower than other commercially cultured snapper species. After applying the data generated by this study, recently published species selection methodology rank the red snapper within the highest priority tier for aquaculture development in the Southeastern United States and the Caribbean region.

Building a Teleost Fish Traceability Program Based on Genetic Data from Pacific Panama Fish Markets.

Fish tissue samples from 203 adult individuals were collected in the main ports and markets of the Pacific coast of Panama. Molecular identification based on a cytochrome oxidase I gene segment of all species was verified by GENBANK reference sequences. A total of 34 species from 14 families (Ariidae, Caranjidae, Centropomidae, Gerreidae, Haemulidae, Lobotidae, Lutjanidae, Malacanthidae, Mugilidae, Scianidae, Scombridae, Serranidae, Sphyraenidae, Stromateidae) were identified at the species level from 164 sequences. Additionally, three Caribbean species were molecularly identified among the analyzed samples (Mycteroperca xenarcha, Paralonchurus brasilensis and Lobotes surinamensis). Species diversity was slightly higher in the Gulf of Panama than in the Gulf of Chiriquí. For species with five or more individual sequences, genetic diversity and genetic connectivity parameters such as total number of haplotypes (H), haplotype diversity (Hd), and nucleotide diversity (π) were calculated. Overall, pelagic-migratory species showed higher values of genetic diversity than coastal and estuarine species with some exceptions. Connectivity between Gulf areas was compared using values of genetic distances and genetic differentiation (Fst). The high level of connectivity observed between the Gulf of Chiriqui and the Gulf of Montijo indicates the existence of a single stock in that area for the following species: Scomberomorus sierra, Caranx caninus and Lutjanus guttatus. The demographic history of the most common species was examined using Tajima's D values, suggesting population expansion for two snapper species, L. peru and L. argentiventris, having significant and higher values. Another important contribution from this research was the production of primers and dual-labeled probes for environmental DNA detection using qPCR for the five most abundant species (spotted rose snapper, yellow snapper, green jack, Pacific crevalle jack and the Pacific sierra fish). These markers represent a new set of tools for environmental DNA (eDNA) detection and molecular traceability of three commercially important fish species along the supply chain including landing sites and markets of the main fishery areas.

Phylogenetic of red snapper (Lutjanidae) in Yapen Island Waters, Papua, Indonesia

Abstract. Sala R, Kusuma AB, Pranata B. 2022. Phylogenetic of red snapper (Lutjanidae) in Yapen Island Waters, Papua, Indonesia. Biodiversitas 23: 6428-6436. Red snappers are an economically valuable fishery resource. Most of these snapper species are inhabitants of coral reef ecosystems. A variety of red snapper species can be found in the northern waters of Papua, particularly in the Yapen Regency. However, information regarding the biological and ecological aspects of these fish is virtually unavailable. On the other hand, the utilization intensity of red snapper as a source of community income continues to increase. By using DNA barcode sequences, this study attempted to examine species diversity and relationships among Lutjanidae family species. The study was carried out from June to August 2022 in the waters of Yapen Regency by taking fish samples from the fish caught by local hand-lining fishers. Red snapper samples were identified morphologically and molecularly. According to molecular analyses, it was identified nine red snapper species from the genera of Lutjanus, Aphareus and Pristipomoides. The morphological characteristics of the species from the genus of Aphareus are similar to those from the genus of Pristipomoides yet different from those of the species from the genus of Lutjanus. The phylogenetic tree consisted of four clades with significant bootstrap values ranging from 98 to 99%. Clades 1, 2 and 3 comprise the species from the genus of Lutjanus, while clade 4 contains species from the genera of Aphareus and Pristipomoides. The greatest genetic distance was found between Lutjanus fulvus and Pristipomoides multidens, while the smallest genetic distance was found between Lutjanus vitta and Lutjanus ehrenbergii. Based on the study results, some management implications are discussed. For example, information on species biodiversity maps is needed to determine the target stock of a managed species so that management objectives are more focused on the species level and not on the genus or family level.

Morphometric and genetic variations of four dominant species of snappers (Lutjanidae) harvested from the Northern Coast of Aceh waters, Indonesia

Lutjanus commonly known as snappers are economical fishes in the world, including in Indonesia. They have high morphological similarities and are difficult to distinguish. Therefore, this study aimed to validate the taxonomic status and kinship of four dominant snappers harvested from the northern coastal waters of Aceh, Indonesia, namely Lutjanus bengalensis, Lutjanus kasmira, Lutjanus gibbus, and Lutjanus fulviflamma. The samples were collected from Pulo Aceh and Lampulo fish landings. A total of 60 samples of each species were used for morphometric analysis using the traditional morphometric approach, while five from each of them served as samples for the genetic analysis with the COI gene. Morphological analysis showed that the four fish species were categorized into 3 different groups, where L. bengalensis and L. kasmira were in the same group. The genetic analysis revealed that they were grouped into four different clades, but L. bengalensis and L. kasmira were located in the same sister clade, indicating genetic closeness. L. bengalensis, L. kasmira, L. gibbus, and L. fulviflamma had two, three, three, and four haplotypes, respectively. Based on the results, the COI gene successfully distinguished the four species of snapper, where L. bengalensis and L. kasmira had morphological and genetic similarities. Furthermore, L. fulviflamma had higher genetic diversity than the others.

Life-history traits variation of Lutjanus malabaricus (Bloch & Schneider, 1801) in the waters off Northern Vietnam

Abstract Lutjanus malabaricus represents a widely distributed and intensively exploited snapper species. The present article is the first attempt to describe the life-history traits of L. malabaricus in Vietnamese waters and estimate their variability. The fish were collected at the landing sites of Nghe An and Ha Tinh provinces from June 2020 to May 2021. The standard length of fish ranged from 10 to 74 cm, weight varied between 18.53 and 8972.89 g, age ranged from 1 to 17 years and all three parameters were subjected to a significant seasonal variation. A similar seasonal pattern was observed in the variation of maturity and gonadosomatic index. We assume that the observed variation of the stock structure is the result of spawning migrations when large fish migrate inshore from the foraging grounds. Growth and weight gain of fish were described via the von Bertalanffy function, constants of the equations were as follows: L∞ = 76.2, K = −0.077, t0 = −2.26 in males and L∞ = 56.9, K = −0.176, t0 = −0.48 in females; W∞ = 6498, K = −0.100, t0 = −1.96 in males and W∞ = 8317, K = −0.100, t0 = −1.31 in females. The growth constants of the North Vietnamese stock of L. malabaricus are similar to the ones of the North-eastern Australian stock. A general tendency for the reduction of the growth rate and asymptotic size from equatorial waters to higher latitudes was observed.

Molecular delimitation methods validate morphologically similar species of red snappers (Perciformes: Lutjanidae).

In this study, we tested the taxonomic validation of red snappers species (Southern red snapper Lutjanus purpureus; Silk snapper L. vivanus; Blackfin snapper L. buccanella; and Pacific red snapper L. peru) based on comparative analysis, using four methods for species delimitation. These methods were based on either genetic similarity or phylogenetic trees inferred from two mitochondrial (Cytochrome b and D-loop) and two nuclear (Myostatin and S7 introns) markers. On one hand, the genetic results corroborated the presence of four red snapper species, confirming their taxonomic validation despite their remarkable morphological similarity. On the other hand, few incongruencies in the species delimitation methods were observed according to the phylogenetic reconstruction method (maximum likelihood or Bayesian inference) when using. Based on the phylogenetic results, L. buccanella should represent a more ancient lineage in relation to the clade that encompasses L. purpureus, L. peru and L. vivanus. The single-locus phylogenetic analysis based on Cytb recovered each the red snapper species as a well-supported clade. Overall, this study provided a DNA-based validation of the traditional morphological taxonomy of red snappers.