Comparative study of lipids and fatty acids in the liver, muscle, and eggs of wild and captive common snook broodstock

In this study, the lipid composition of wild and captive common snook broodstock were investigated to identify potential nutritional deficiencies and formulate suitable diets for captive stocks. Results showed captive snook incorporated significantly more lipid than their wild counterparts. However, cholesterol and arachidonic acid (ARA) levels were significantly lower compared to wild fish, which may impact steroid and prostaglandin production, reproductive behavior and gametogenesis. In eggs obtained from captive broodstock, high docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) levels, associated with low ARA contents were found. As a result, ARA/EPA ratio in captive eggs was less than half of that in wild eggs with the potential for negative consequences on embryo and larval development. In conclusion, large differences were noticed between wild and captive broodstock that may contribute to the reproductive dysfunctions observed in captive snook broodstock (e.g. incomplete oocyte maturation, low milt production and highly variable egg and larval quality). The wild snook survey also identified the presence of hydrocarbons in the liver, which should be further studied to identify a potential impact on the reproductive performances of a vulnerable population like common snook

Severe glomerular disease in juvenile grey snapper Lutjanus griseus L. in the Gulf of Mexico caused by the myxozoan Sphaerospora motemarini n. sp.

AbstractIn the eastern Gulf of Mexico, off the coast of Florida, grey snapper, Lutjanus griseus was found to be infected with the myxozoan parasite Sphaerospora motemarini n. sp., with high prevalence (83%) and intensity of infection occuring in age-0 fish, and with parasite levels decreasing with age (age-1 snapper 40%; age-2 snapper 0%). The morphological, molecular and phylogenetic characterisation of the myxozoan showed that it is a member of the typically marine, polysporoplasmid Sphaerospora spp. which form a subclade within the Sphaerospora sensu stricto clade of myxozoans, which is characterised by large expansion segments in their SSU rDNA sequences. Presporogonic stages of S. motemarini n. sp. were detected in the blood, using PCR. Pseudoplasmodia and spores were found to develop in the renal corpuscles of the host, causing their massive expansion. Macroscopic and histopathological changes were observed in age-0 fish and show that S. motemarini n. sp. causes severe glomerulonephritis in L. griseus leading to a compromised host condition, which makes it more susceptible to stress (catch-and-release, predators, water quality) and can result in mortalities. These results are discussed in relation to the exploitation of grey snapper populations by commercial and recreational fisheries and with the observed increased mortalities with temperature along the coast of Florida. In the future, we would like to determine prevalence and intensity of infection with S. motemarini n. sp. in juvenile L. griseus in different areas of the Gulf of Mexico in order to be able to estimate the temperature dependence of S. motemarini n. sp. proliferation and to be able to predict its distribution and severity during climatic changes in the Gulf

Microalgae (Diatom) Production — The Aquaculture and Biofuel Nexus

As fishing has become more industrialized and wild fish stocks increasingly depleted, aquaculture production has grown rapidly to address the shortfalls in capture fisheries and limitations to long-term aquaculture success. One such shortfall is the need to produce a suitable, sustainable, substitute for the capture fishery derived fish meal and oil based fish feeds currently in use, while maintaining the human protein requirements and health benefits of Long Chain (LC) omega-3 oils in farmed fish products. Fish derive the LC omega-3 oils from the food they consume, which ultimately comes from lower trophic level primary producers like microalgae. Using Integrated Aquaculture System (IAS) principles and practices, microalgae (diatoms) can be raised and processed directly for their Algal/Single Cell Oils (SCO), protein, and nutrients. Besides the use as an aquaculture feedstock, microalgae have been investigated for biofuel production because of higher photosynthetic efficiency, higher biomass production, and faster growth compared to other terrestrial energy crops. SCO based carbon-neutral renewable liquid biofuel solutions are currently under investigation but suffer from high production costs. Liquid biofuels have been considered to displace non-renewable, petroleum-derived transport fuels of limited availability which contribute to climate change via greenhouse gas (GHG) emissions. The current high cost constraint of SCO production could be alleviated through explored water-energy-food nexus synergies between the aquaculture and biofuels sector with a concentration on innovations in microalgae/SCO production, harvesting, and processing technologies. Interdisciplinary collaborations between engineers, biologists and chemists are essential for their successful development

De Novo Assembly and Transcriptome Dataset of Liver, Testis and Head Kidney from Red Drum (\u3cem\u3eSciaenops ocellatus\u3c/em\u3e)

Red drum (Sciaenops ocellatus) is an estuarine Sciaenid with high commercial value and recreational demand. During the past 50 years, overfishing has caused declines in the population that resulted in the development of red drum commercial and stock enhancement aquaculture fisheries. Despite the potential high economic value in both wild and aquaculture commercial fisheries the availability of transcriptomic data for red drum in public databases is limited. The data here represents the transcriptome profiles of three tissues: liver, testis and head kidney from red drum. The data was generated using Illumina high-throughput RNA sequencing, Trinity for de novo assembly and Blast2GO for annotation. Six individual libraries were pooled for sequencing of the transcriptome and the raw fastq reads have been deposited in the NCBI-SRA database (accession number SRP11690)

De Novo Assembly and Transcriptome Dataset of Liver, Testis and Head Kidney from Red Drum (\u3cem\u3eSciaenops ocellatus\u3c/em\u3e)

Red drum (Sciaenops ocellatus) is an estuarine Sciaenid with high commercial value and recreational demand. During the past 50 years, overfishing has caused declines in the population that resulted in the development of red drum commercial and stock enhancement aquaculture fisheries. Despite the potential high economic value in both wild and aquaculture commercial fisheries the availability of transcriptomic data for red drum in public databases is limited. The data here represents the transcriptome profiles of three tissues: liver, testis and head kidney from red drum. The data was generated using Illumina high-throughput RNA sequencing, Trinity for de novo assembly and Blast2GO for annotation. Six individual libraries were pooled for sequencing of the transcriptome and the raw fastq reads have been deposited in the NCBI-SRA database (accession number SRP11690)

Parental contribution and spawning performance in captive common snook Centropomus undecimalis broodstock

Common snook are a species relatively new to aquaculture and to date, virtually no information is available on captive broodstock spawning characteristics. Understanding basic and fundamental data such as broodstock contribution of captive mass spawning snook is important, not only for the development of a successful selective breeding program for the species, but also for restocking wild fisheries and maintenance of local genetic variation. A scoping study was undertaken to explore the potential of DNA profiling for monitoring mating outcomes in captive snook. Spawning success was monitored among wild harvested broodstock that were undergoing hormonal treatment to induce spawning. The broodstock were maintained in three separate tanks (Tank A: 18 males and 15 females; Tank B: 22 males and 11 females; Tank C: 40 males and 16 females) and were subject to different handling stresses. Sixteen mass spawning events were studied across the three tanks over a 15month period. DNA profiling of eight microsatellite markers was employed to detect and quantify individual parental contributions for 2,154 larvae obtained from the three tanks. The panel of loci was generally robust and allowed unambiguous assignment of 89% of larvae to a single family. All spawns occurred within approximately 24 to 72hours post-implantation and only females implanted with gonadotropin releasing hormone analogue (GnRHa) were found to contribute. Overall, spawning performance among the three tanks was highly variable in terms of the total number of eggs produced (from 86,300 to 2,378,000 per spawn), fertilization success (from 17.0 to 87.3%) and hatch rate (from 47.8 to 98.1%). Three-day larval survival ranged from approximately 25.9 to 90.1% in tank A and 19.9 to 74.2% in tank C. During this study, new information regarding requirements for broodstock husbandry, mating patterns and spawning periodicity of captive common snook broodstock were obtained. Spawn contribution data 1) provided a confirmation of GnRHa treatment efficacy in female snook with a minimum stage of oogenesis (late secondary growth-SGl) required for successful spawning; 2) identified a potential impact of handling on maturation and spawning in male and female broodstock; 3) confirmed that, through photothermal conditioning, captive common snook broodstock can spawn over consecutive days and several times per year, including outside of their natural spawning season