Shrimp Populations Research Articles

Dynamics of metal/metalloid bioaccumulation and sensitivity in post-larvae shrimp (Macrobrachium rosenbergii) exposed to settleable atmospheric particulate matter from an industrial source

The metallurgy industry is a potent global source of particulate matter (PM) atmospheric emissions. A portion of this PM may settle in aquatic (SePM) carrying metal/metalloid particles and metallic nanoparticles. Surprisingly, this form of contamination has not received due attention from most environmental monitoring agencies. We analyzed the effect of exposure to SePM on shrimp post-larvae, a critical stage for the viability of shrimp populations and for the trophic chain. After acclimation, shrimp were exposed to contaminants using a randomized experimental design—a 4 × 4 factorial arrangement with 2 factors: exposure time (24, 48, 72, and 96 h) and SePM concentration (0.00, 0.01, 0.10, and 1.00 g L−1). The bioaccumulation of metals, contamination rates, mortality, and ROS-related biomarkers (lipid peroxidation – LPO; DNA strand breakage DNA SB and metallothionein content – MTs;) were evaluated. After contamination, the water contained 27 different metals/metalloids. Post-larvae accumulated metals, such as Cd, Pb, Al, As, Se, Sr, Zr, Ba, La, Ce, W, and Hg. However, the rise in SePM did not result in a proportional bioaccumulation rise, indicating that effective biological barriers may work for some metals. Although the different levels of SePM changed mortality dynamics, they resulted in a similar final lethality (60–80 %). SePM caused significant damage to lipids (increased LPO), genetic material (DNA SB), and increased Mts. Such effects may reflect a particularly deleterious ecological problem as it is present at such an early stage of life. These results identified a clear environmental risk since the lower level of exposure used was 102 times lower than that measured in the habitats affected by local industry. Consequently, our results emphasize the need for clear protocols for monitoring the effects of SePM in aquatic environments.

The influence of temperature and β-1,3-glucans on the occurrence of white spot syndrome virus and white spot disease in post-larvae of Penaeus vannamei shrimp

Penaeus vannamei is the main species of shrimp farmed worldwide, and for Ecuador it is the first non-oil economic sector. However, various pathogens, including white spot syndrome virus (WSSV), threaten the sustainability of shrimp farming. P. vannamei larvae are susceptible to WSSV infection via vertical or horizontal transmission. To decrease the incidence of WSSV in PLs, a bioassay was performed by exposing P. vannamei shrimp (PL25), which were negative for WSSV and white spot disease (WSD), to two protective factors, water temperature (T = 24 °C and T = 31 °C), and immunestimulation using β-1,3-glucans (BG) (with and without BG added to the food), using a crossed two-factor design, for 20 days. The incidence of WSSV and WSD was modeled using generalized linear model (GLM). The strength of the association between the response and explanatory variables was estimated using the odds ratio [Exp (Beta)] and interpreted as the level of risk for the incidence of WSSV or WSD in one of the categories compared to the baseline category in the GLM. Odds ratios were considered significant if their 95 % confidence interval did not include the value 1. The results showed that BG had a significant negative effect on the number of WSSV-positive animals. In addition, a lower probability of WSSV infection was determined by combining 31 °C and BG. In this treatment, the WSD injuries were almost undetectable. Most larvae shrimps affected by WSD exhibited injuries to the antennal gland and connective tissue. In situ hybridization analysis revealed that 29 % of shrimp, initially negative by histology, were positive for WSSV. The virus was detected mainly in the nervous tissue of the head, epithelium, connective tissue of the head appendages, and the oral region surrounding the integumental glands. Apoptosis analysis showed a weak signal in nerve tissue but was more intense in epithelial cells of the head appendages, in association with cuticular damage. According to the findings, WSSV could disseminate among shrimp populations by infecting them through the TG and epithelium of the head appendage, followed by connective tissue and nervous tissue. However, applying BG at 31 °C may serve as a protective measure to reduce WSD injuries and restrict WSSV dissemination.

Enhancing Sustainability and Conservation of White Shrimp Penaeus schmitti in Northeast Brazil: Insights Into Life History, Reference Points, and Management Strategies for Beach Seining

ABSTRACTArtisanal fishing significantly not only contributes to socioeconomic development of numerous countries but also exerts pressure on natural populations. The white shrimp (Penaeus schmitti) is a key species in Brazilian artisanal fisheries, yet it is currently classified as data‐deficient. Conducting comprehensive studies on its population dynamics is essential to establish reference points that guarantee sustainable fishing. Therefore, we estimated population parameters to assess status of the white shrimp stock captured by beach seining in Northeast Brazil. Monthly samples of white shrimp were collected using a beach trawl. Based on population parameters, the white shrimp population in the study area, the sex ratio was 1 male to 1.29 females, with females larger and heavier than males. Weight–length relationships revealed positive allometric growth for males, females, and grouped sexes, with no significant difference between sexes. Asymptotic length, t_achor, and growth performance index also did not differ between sexes; however, the growth coefficient was higher for females. Beach trawling in northeastern Brazil predominantly targeted adult white shrimp, with carapace length at first capture (Lc50) averaging 2.12 cm for females and 2.19 cm for males. Mortality and exploitation rates were below maximum sustainable levels, so the stock was classified as underexploited. Overall, beach‐seine fishing was less harmful to this stock (F = 1.42) than motorized fishing and can be considered a sustainable fishing activity for the white shrimp population.

The genetic basis of resistance to Enterocytozoon hepatopenaei (EHP) and White feces syndrome (WFS) in the whiteleg shrimp (Litopenaeus vannamei)

The microsporidian Enterocytozoon hepatopenaei (EHP) is a yeast-like intracellular fungus, that in the last decade has significantly contributed to major economic losses in the whiteleg shrimp (Litopenaeus vannamei) industry worldwide. In commercial ponds, EHP affected shrimp frequently also shows symptoms of White Feces Syndrome (WFS), characterized by floating white fecal strings, reduced feed consumption, and growth retardation. To elucidate the genetic basis of resistance to EHP + WFS, a challenge test was conducted using a pedigreed shrimp population from the Benchmark Genetics breeding program in Colombia. Out of the total genotyped animals, 1436 individuals from 47 families successfully passed quality control, underwent parentage analysis, had phenotypic records and were available for further analysis. Moderate heritabilities were estimated for binary survival to EHP + WFS using pedigree based (0.31 ± 0.04) and genomic analysis (0.41 ± 0.06). Furthermore, a low genetic correlation between body weight and EHP + WFS challenge test survival traits was observed, implying that genetic improvement of resistance to EHP + WFS can be achieved without compromising growth performance. The genome-wide association analysis showed little evidence for any major QTL, indicating that multiple genes with small effects collectively contribute to EHP + WFS resistance. Furthermore, cross validation analysis showed 0.54 ± 0.01 accuracy of prediction for genomic analysis and 0.49 ± 0.001 for the pedigree analysis, indicating the relevance of a genomic selection strategy for achieving genetic improvement for EHP + WFS resistance in L. vannamei.

Screening for White Spot Syndrome Virus (WSSV) in pink shrimp (Penaeus paulensis) from Rocha Lagoon, Uruguay

Penaeus paulensis (pink shrimp) is an important resource for small-scale fisheries in the brackish coastal lagoons of Uruguay. No viral diseases have been detected in shrimp populations in the Uruguayan territory. The presence of viral pathogens, such as White Spot Syndrome Virus (WSSV) and Infectious Hypodermal Haematopoietic Necrosis Virus (IHHNV) in wild shrimp populations has been previously reported in Brazil and Argentina.We investigated the presence of WSSV in wild populations of penaeid shrimp from Rocha Lagoon, Uruguay. We sampled 70 specimens of juvenile P. paulensis and assessed the presence of these viral pathogens using nested PCR and histology. Gill tissue from the 70 samples was divided into 14 pools of 5 individuals for DNA extraction and PCR analysis. We also retested each pooled sample individually. The nested PCR procedure described in the WOAH aquatic animal manual was used. A subset of 20 individual specimens were also processed using standard histological techniques.The results showed that WSSV was not detected in the pooled or individually tested samples. We found no evidence of the presence of the viral genome or gill lesions in the samples analysed. This indicates that the fishery is still likely to be free of WSSV infection. The procedures and information generated can be used as a baseline study for future implementation of surveillance programmes in the country.

Spatiotemporal modelling of northern shrimp Pandalus borealis distribution patterns throughout Canada’s subarctic and arctic regions

Northern shrimp Pandalus borealis occur throughout Canada’s Atlantic Ocean, where they are thought to form a single population spanning from Baffin Bay to the tail of the Grand Bank. Here, they play an important role in the ecosystem as prey for many taxa and have been targeted by a lucrative large-scale fishery since the 1970s. Yet, we still understand little about which (and how) ecosystem and environmental factors influence their distribution and abundance. We used survey data collected over 29 yr throughout 23 degrees of latitude to develop a spatiotemporal model predicting northern shrimp density. We confirmed that both top-down drivers (e.g. predation pressure), as well as bottom-up drivers (e.g. bottom temperature) play important roles in determining both the presence and abundance of northern shrimp. The model was used to predict the density of northern shrimp throughout the entire study area from 2005 to 2022. Our results highlight the importance of understanding ecosystem and environmental dynamics in relation to northern shrimp population patterns and trends within resource assessments.

Transcriptomic Insights and the Development of Microsatellite Markers to Assess Genetic Diversity in the Broodstock Management of Litopenaeus stylirostris.

The Pacific blue shrimp (Litopenaeus stylirostris) is a premium product in the international seafood market. However, intensified farming has increased disease incidence and reduced genetic diversity. In this study, we developed a transcriptome database for L. stylirostris and mined microsatellite markers to analyze their genetic diversity. Using the Illumina HiSeq 4000 platform, we identified 53,263 unigenes from muscle, hepatopancreas, the intestine, and lymphoid tissues. Microsatellite analysis identified 36,415 markers from 18,657 unigenes, predominantly dinucleotide repeats. Functional annotation highlighted key disease resistance pathways and enriched categories. The screening and PCR testing of 42 transcriptome-based and 58 literature-based markers identified 40 with successful amplification. The genotyping of 200 broodstock samples revealed that Na, Ho, He, PIC, and FIS values were 3, 0.54 ± 0.05, 0.43 ± 0.09, 0.41 ± 0.22, and 0.17 ± 0.27, respectively, indicating moderate genetic variability and significant inbreeding. Four universal microsatellite markers (CL1472.Contig13, CL517.Contig2, Unigene5692, and Unigene7147) were identified for precise diversity analysis in Pacific blue, Pacific white (Litopenaeus vannamei), and black tiger shrimps (Penaeus monodon). The transcriptome database supports the development of markers and functional gene analysis for selective breeding programs. Our findings underscore the need for an appropriate genetic management system to mitigate inbreeding depression, reduce disease susceptibility, and preserve genetic diversity in farmed shrimp populations.

Selective Acoustic Trapping, Translating, Rotating, and Orienting of Organism From Heterogeneous Mixture.

Selective contactless manipulation of organisms with intrinsic mobility from heterogeneous mixture is essential for biomedical engineering and microbiology. Acoustic manipulation, compared to its optical, magnetic, and electrostatic counterparts, provides superior bio-compatibility and additive-free properties. In this study, we present an acoustic manipulation system capable of selectively trapping, translating, rotating, and orienting individual organisms from in-Petri dish organism mixture using a phased transducer array and microscope, by dynamically steering the acoustic field. Specifically, using brine shrimp and zebrafish populations as example, the to-be-manipulated organisms with different sizes or morphologies can be manually designated by the user in microscopic image and interactively localized. Thereafter, the selected organisms can be automatically trapped from the heterogeneous mixture using a multiple focal point-based acoustic field steering method. Finally, the trapped organisms can be translated, rotated, and oriented in regard to the user's distinct manipulation objectives in instant response. In different tasks, closed-loop positioning and real-time motion planning control are performed, highlighting the innovation in terms of automation and accuracy of our manipulation technique. The results demonstrate that our acoustic manipulation system and acoustic field steering method enable selective, stable, precision, real-time, and in-Petri dish manipulation of organisms from heterogeneous mixture.

Transcriptome and metabolome for identifying key metabolites impacting the Vibrio parahaemolyticus in Litopenaeus vannamei

IntroductionShrimp is an important aquaculture species worldwide. Vibrio parahaemolyticus (VP) is an opportunistic pathogen of Litopenaeus vannamei that can cause diseases such as acute hepatopancreatic necrotic disease (AHPND), resulting in significant losses to the shrimp farming industry.MethodsIn this study, We analyzed two shrimp populations by transcriptomics and non-targeted metabolomics, which exhibited significant differences in resistance to VP. Through integrated analysis, we identified genes and metabolites linked to the development of shrimp's resistance to VP.Results and discussionThe analysis revealed that the differential metabolism of flavonoid compounds, especially quercetin, significantly influences the expression of shrimp's resistance to VP. Supplementing feed with an appropriate quantity of quercetin has the potential to increase the expression of crucial genes in the NF-κB pathway, including TLR and AP1, along with the expression of the antibacterial peptide crustin, resulting in a decreased mortality rate. Together, these results indicate that an appropriate amount of quercetin can strengthen the immune response of shrimp to VP, thereby reducing the incidence of AHPND.

Analysis of Elimination Effects of Inbreeding on Genotype Frequency in Larval Stages of Chinese Shrimp.

Marine animals possess genomes of considerable complexity and heterozygosity. Their unique reproductive system, characterized by high fecundity and substantial early mortality rates, increases the risk of inbreeding, potentially leading to severe inbreeding depression during various larval developmental stages. In this study, we established a set of inbred families of Fenneropenaeus chinensis, with an inbreeding coefficient of 0.25, and investigated elimination patterns and the manifestations of inbreeding depression during major larval developmental stages. Reduced-representation genome sequencing was utilized to explore the genotype frequency characteristics across two typical elimination stages. The results revealed notable mortality in hatching and metamorphosis into mysis and post-larvae stages. Inbreeding depression was also evident during these developmental stages, with depression rates of 24.36%, 29.23%, and 45.28%. Segregation analysis of SNPs indicated an important role of gametic selection before hatching, accounting for 45.95% of deviation in the zoea stage. During the zygotic selection phase of larval development, homozygote deficiency and heterozygote excess were the main selection types. Summation of the two types explained 82.31% and 89.91% of zygotic selection in the mysis and post-larvae stage, respectively. The overall distortion ratio decreased from 22.37% to 12.86% in the late developmental stage. A total of 783 loci were identified through selective sweep analysis. We also found the types of distortion at the same locus could change after the post-larvae stage. The predominant shifts included a transition of gametic selection toward normal segregation and other forms of distortion to heterozygous excess. This may be attributed to high-intensity selection on deleterious alleles and genetic hitchhiking effects. Following larval elimination, a greater proportion of heterozygous individuals were preserved. We detected an increase in genetic diversity parameters such as expected heterozygosity, observed heterozygosity, and polymorphic information content in the post-larvae stage. These findings suggest the presence of numerous recessive deleterious alleles and their linkage and suggest a major role of the partial dominance hypothesis. The results provide valuable insights into the mechanisms of inbreeding depression in marine animals and offer guidance for formulating breeding strategies in shrimp populations.

Growth and reproduction of the shrimp population in a lagoon system in southern Benin (West Africa)

Abstract The aim of this work was to characterize the growth and reproduction dynamics of shrimp in the Lac Nokoué-Chenal de Cotonou complex. The results of one year’s sampling from five stations (North, South, East, Central and West) of the lagoon complex revealed that linear growth in size in Lake Nokoué is decreasing over time in Macrobrachium macrobrachion (the most representative species of the genus Macrobrachium), but positive in Penaeus notialis (the most representative species of the genus Penaeus). Size-weight relationships indicate that the lowest growth coefficient () is obtained in immature males of Macrobrachium felicinum, while the highest growth coefficient () is obtained in mature females of Macrobrachium vollenhovenii, with an average of 2.84 for all shrimp species over both sexes considered. The test indicated that only the species Macrobrachium vollenhovenii has a significant sexual imbalance in favour of females in Lake Nokoué. Fisher’s Least Significant Difference test indicated that the estimated first sexual maturity sizes in Macrobrachium vollenhovenii and M. macrobrachion are significantly different from those estimated in M. felicinum at the threshold. However, the same test indicates that there is not enough evidence to differentiate the sizes of first sexual maturation in M. vollenhovenii and M. macrobrachion. This work revealed that Penaeus monodon was the only species to show better positive growth within all its groups in Lake Nokoué while exposed to anthropogenic effects. A gradual average increase in the size of Penaeus notialis in Lake Nokoué is found between the beginning and end of the saline intrusion (which confirms the life cycle of the species presented). Species of the genus Macrobrachium showed good reproductive capacity, with the absence of sexually mature Penaeus in this lagoon.

Whole genome sequencing of nine Vibrio parahaemolyticus strains encoding (Pir) toxin-like genes from shrimp cultures in northern Peru using Oxford Nanopore technology.

Nine Peruvian isolates of Vibrio parahaemolyticus were characterized through sequencing, revealing the presence of simple sequence repeat, Pir toxin-like genes, and genes associated with antibiotic resistance, toxic components, and transposable elements. These findings expand our understanding of the genetic diversity, disease resistance, and virulence in cultivated shrimp populations in Peru.

Opposing life history strategies allow grass shrimp parasites to avoid a conflict of interest.

A conflict of interest occurs when parasites manipulate the behavior of their host in contradictory ways to achieve different goals. In grass shrimp (Palaemonetes pugio), trematode parasites that use shrimp as an intermediate host cause the shrimp to be more active than usual around predators, whereas bopyrid isopod parasites that use shrimp as a final host elicit the opposite response. Since these parasites are altering the host's behavior in opposing directions, a conflict of interest would occur in co-infected shrimp. Natural selection should favor attempts to resolve this conflict through avoidance, killing, or sabotage. In a field survey of shrimp populations in four tidal creeks in the Cape Fear River, we found a significant negative association between the two parasites. Parasite abundance was negatively correlated in differently sized hosts, suggesting avoidance as a mechanism. Subsequent mortality experiments showed no evidence of early death of co-infected hosts. In behavior trials, co-infected shrimp did not show significantly different behavior from singly infected or uninfected shrimp, suggesting that neither parasite sabotages the manipulation of the other. Taken together, our results suggest that rather than sabotaging or killing one another, bopyrid and trematode parasites tend to infect differently sized hosts, thus avoiding a conflict and confirming the importance of testing assumptions in natural contexts.

Vertical transmission and prevalence of white spot syndrome virus (WSSV) in the wild spawning population of the Indian white shrimp, Penaeus indicus

White spot disease, caused by white spot syndrome virus (WSSV), has historically been the most devastating disease in shrimp aquaculture industry across the world. The mode of virus transmission is the most crucial stage in the dynamics and management of virus infection. This study explored the mechanism of vertical transmission of WSSV in Indian white shrimp, Penaeus indicus, potential native species for domestication and genetic improvement, using quantitative real time PCR (q RT PCR), light and electron microscopy, and in situ hybridization. Wild brooders of P. indicus (n = 2576) were sampled along the South east coast of India, during 2016 to 2021. Of these ∼ 58 % of the brooders were positive for WSSV, and almost 50 % of infected wild brooders were at the various stages of reproductive maturation. WSSV-PCR positive brooders (n = 200) were analysed for vertical WSSV transmission. The q RT PCR studies of reproductive tissues revealed that 61 % (n = 13) of spermatophore, 54 % (n = 28) of immature ovaries and 48 % (n = 27) of ripe ovaries were infected with WSSV. The lowest level of infection was recorded in females with ripe ovaries (6.84 × 101 ± 9.79 × 100 ng genomic DNA) followed by fertilized eggs (1.59 × 102 ± 3.69 × 101 ng genomic DNA), and larvae (nauplius and zoea). The histology of gravid females with high WSSV copies showed pyknotic and karyorrhectic germinal vesicle with degenerated cortical rods. Conversely, the gravid females with low WSSV copies showed fully developed ovary without characteristic signs of WSSV infection. Transmission electron microscopic studies clearly established the presence of WSSV particles in both ovaries and spermatophores. When subjected to in situ hybridization, WSSV-specific signals were observed in connective tissues of spermatophore, although gravid ovary and fertilized eggs were failed to produce WSSV specific signals. The present study provides the first molecular and histological evidence for trans-ovarian vertical transmission of WSSV. Development of disease-free base population being the cornerstone and first step in establishing the breeding program, the present findings could be a basis for development of such programs.

INVASI UDANG AIR TAWAR Macrobrachium lanchesteri DI DANAU BOLANO TOGA, TOLI-TOLI, SULAWESI TENGAH

Sulawesi Island has long been known as one of the regions in Indonesia that holds a wealth of freshwater shrimp species in both lentic and lotic waters. One of the lentic waters in Sulawesi is Lake Bolano Tago which is located in Toli-Toli Regency, Central Sulawesi. This research aims to reveal the population and abundance of freshwater shrimp in the lake. Sampling was carried out in April 2022 along the lake's littoral zone which was divided into 7 stations using purposive sampling and sweep methods. Sampling effort at each station was carried out for 4 hours. Environmental physicochemical factors measured include water temperature, brightness, dissolved oxygen levels, and water acidity levels. Specimen identification was carried out at the Animal Biosystematics and Evolution Laboratory, Biology Department, FMIPA, Tadulako University. Identification was carried out based on morphological characters by following the identification key of Wowor et al (2004). The results of this research revealed that of the freshwater shrimp collected as many as 1,165 individuals in the lake, all consisted of one species, namely Macrobrachium lanchesteri. This species belonging to the Palaemonidae family is not native to Indonesia but comes from the Oriental region. Macrobrachium lanchesteri was first described based on a type specimen originating from Thailand. Its presence in Lake Bolano Toga is quite worrying because of its invasive nature. With the abundant presence of the M. lanchesteri species at all stations, it can be confirmed that the Macrobrachium lanchesteri species has invaded Lake Bolano Toga

Smart nano generation of transgenic algae expressing white spot syndrome virus in shrimps for inner ear-oral infection treatments using the spotted hyena optimizer (SHO)-Long short-term memory algorithm

Nanotechnology offers a promising avenue to amplify the effectiveness and precision of using transgenic algae in managing WSSV in shrimp by possibly crafting nano-carriers for targeted therapeutic agent delivery or modifying algae cells at a molecular level. Leveraging the capabilities of nano-scale interventions, this study could explore innovative means to manipulate cellular processes, control biological interactions, and enhance treatment efficacy while minimizing undesirable impacts in aquatic environments. The White Spot Syndrome Virus (WSSV) is a double-stranded DNA virus with a tail and rod form that belongs to theNimaviridaefamily. There is no workable way to manage this illness at the moment. This research proposes a new model based on the Long Short-Term Memory (LSTM) and Spotted Hyena Optimizer (SHO) method to control the inner ear-oral infection, utilizing transgenic algae (Chlamydomonas reinhardtii). It is pretty tricky to modify the weight matrix in LSTM. The output will be more accurate if the weight of the neurons is exact. Histological examinations and nested polymerase chain reaction (PCR) testing were performed on the challenged shrimp every 4 h to assess the degree of white spot disease. The SHO-LSTM has shown the highest accuracy and Roc value (98.12% and 0.93, respectively) and the lowest error values (MSE = 0.182 and MAE = 0.48). The hybrid optimized model improves the overall inner ear-oral linked neurological diseases detection ratio. Additionally, with the slightest technical complexity, it effectively controls the forecast factors required to anticipate the ENT. Algal cells were found to be particularly well-suited for inner ear-oral infections, and shrimps fed a transgenic line had the best survival ratio in WSSV infection studies, with 87% of the shrimp surviving. This shows that using this line would effectively stop the spread of WSSV in shrimp populations.

Gut microbiome variation based on 16S rRNA gene amplicon sequencing of the wild and domesticated broodstock populations of black tiger shrimp (Penaeus monodon) in the Indo-Pacific region

Gut microbiome variation has functional importance on host fitness, ecology, and evolution, but the scope and basis of microbial diversity for marine shrimp are still not fully understood. The aim of present study is to characterize the gut microbiomes of five Penaeus monodon broodstocks populations of wild and aquaculture environments within the Indo-Pacific region. We conducted data analysis of 16S rRNA gene amplicons using Qiime2 and Microbiomeanalyst and functional prediction by FAPROTAX (Functional Annotation of Prokaryotic Taxa). Our results identified considerable variation in the gut microbiomes of wild and cultured shrimps, presumably reflecting differences in diet, host genetic divergence, and host-bacteria co-evolution. While wild shrimp broodstocks had higher gut microbial diversity, a pronounced divergence of core microbiota was detected in PCOA analysis for both wild and cultured shrimp populations with altered community structure and predicted metabolic functions. Proteobacteria was observed to be dominated in the gut microbiome in all P. monodon populations, whereas Gracilibacteria and Fusobacteriia were only found in domesticated populations. Interestingly, probiotic bacteria such as genus Enterococcus and Lactobacillus were observed to be the core genus for both wild populations with range from 1.08% to 17.67%. LEfSe analysis detected significant enrichment of beneficial/opportunistic pathogens from the gut microbiome of each host population, suggesting possible biomarkers for host health monitoring. Our results provide insights into the deterministic factors contributing to the interpopulation variation in the P. monodon microbiome, highlighting potential future research directions in areas such as host-bacteria co-evolution and holobiome, which may enable the assessment of host-species genomic divergence across environmental gradients.

Parasitism (Flamingolepis liguloides Gervais, 1847) with High Prevalence in Brine Shrimp Population from Çamaltı Saltworks

The species of Artemia (Brine shrimp) populations in saltworks have been gaining an increasing popularity for aquaculture and for its significance for aquatic ecosystem as being an important sustainance for water birds in hypersaline food webs. Besides, species in the genus Artemia sp. are the intermediate host of severe cestode species which are associated with flamingos. In this study, the prevalence of Flamingolepis liguloides parasitism in Artemia parthenogenetica in Turkie was reported. Infected A. parthenogenetica (nature strain) was sampled in saltpans from April to September 2022, where flamingo birds and salt production were available for parasitological diagnosis. The parasites were determined in the abdomen, thorax and near the gut tract of A. parthenogenetica. The highest prevalence of parasite was found in juvenile individuals as 86.67±1.45% and 76.06±1.16% in adults in May. The main intensity was varied from 1.18±0.01 to 1.92±0.06 parasites per infected host depending on the sampling months and age of brine shrimp. The most abundant parasite infestation was recorded as 1.44±0.02 parasites per investigated host in juvenile brine shrimp in June since seasonal conditions are favorable for such infestation.

Distribution pattern and habitat use of the protandrous shrimp Pandalus latirostris in relation to environmental characteristics in Akkeshi waters on the pacific coast of eastern Hokkaido, Japan

A sampling of the protandric shrimp, Pandalus latirostris, was conducted at fixed sites from July 2015 to March 2020 in Akkeshi Bay and the connecting Lake Akkeshi on the Pacific coast of eastern Hokkaido. Based on the occurrence pattern of P. latirostris, most individuals begin mating as males at Age-1, followed by a sex change to females, spawn eggs as females at Age-2, and hatch their eggs in the spring of Age-3. Pre-hatching ovigerous females were mainly found in eelgrass beds near and in Lake Akkeshi, where the water temperature was relatively high. The females probably migrate there to hatch their eggs, making sure of the high survival and growth of the hatched larvae. Juveniles and small males were also abundant in near and in Lake Akkeshi, indicating that many larvae remained in the eelgrass beds where they hatched. These eelgrass beds play an important role in the maintenance of the shrimp population as a major egg-hatching site and nursery habitat in Akkeshi waters. With ontogenetic development, the occurrence rate of P. latirostris gradually increased on the offshore side of Akkeshi Bay, with its body size being larger. As P. latirostris grow, they will probably disperse to the offshore side of Akkeshi Bay. However, the density of P. latirostris in the eelgrass bed in the bay near the lake was extremely high, with its strong preference at all ontogenetic stages. This eelgrass bed would help maintain the shrimp population as a “key habitat” for the shrimp. The site-specific environmental characteristics of vegetation beds influence the distribution and abundance of individuals within a population of P. latirostris through their growth and the associated change in habitat preference. In this study, the importance of maintaining the diverse habitats of P. latirostris will be discussed as part of the shrimp stock management measures.

Exploring Genetic and Morphological Integrity across Ocean Basins: A Case Study of the Mesopelagic Shrimp Systellaspis debilis (Decapoda: Oplophoridae)

Plankton communities often consist of cosmopolitan species with an extensive gene flow between populations. Nevertheless, populations of some plankton species are genetically structured, owing to various barriers such as ocean currents, hydrological fronts, and continents. Drivers that could explain the genetic structures of most mesopelagic species remain unknown on an ocean-basin scale, and our study aims to analyze the genetic and morphological differences between populations of a cosmopolitan mesopelagic shrimp, Systellaspis debilis, from the Southern and Northern Atlantic Ocean, and the Southwest Indian Ocean. We analyzed the ITS-1 and COI markers of 75 specimens and assessed the genetic integrity and within-species variability of these genes. We also coded 32 morphological characteristics in 73 specimens, analyzed their variability, and assessed the correlation between morphological and genetic characteristics using a Redundancy analysis and Mantel test. Systellaspis debilis was genetically cohesive across the whole Atlantic and Southwest Indian Oceans, which is possibly a result of an intensive gene flow through ecological barriers, the resistance of species to hydrological gradients, a purifying selection of mitochondrial genes, etc. In contrast, we found significant morphological differences between populations from different regions, which mirrors morphological diversification and calls for further genomic approaches in order to understand the basis of these variations and uncover potential local adaptations.