16S amplicon-based microbiome biomapping of a commercial broiler hatchery.

Hatcheries, where eggs from multiple breeder farms are incubated and hatched before being sent to different broiler farms, represent a nexus point in the commercial production of broilers in the United States. Considering all downstream microbial quality and safety aspects of broiler production (live production, processing, consumer use) can be potentially affected by the hatchery, a better understanding of microbial ecology within commercial hatcheries is essential. Therefore, a commercial broiler hatchery was biomapped using 16S rRNA amplicon-based microbiome analyses of four sample type categories (Air, Egg, Water, Facility) across five different places in the pre-hatch, hatch, and post-hatch areas. While distinct microbiota were found for each sample type category and hatchery area, microbial community analyses revealed that Egg microbiota trended towards clustering with the facility-related samples when moving from the prehatch to post-hatch areas, highlighting the potential effect of the hatchery environment in shaping the pre-harvest broiler-related microbiota. Prevalence analyses revealed 20 ASVs (Core20) present in the core microbiota of all sample types and areas, with each ASV possessing a unique distribution throughout the hatchery. Interestingly, three Enterobacteriaceae ASVs were in the Core20, including Salmonella. Subsequent analyses showed that Salmonella, while a minor prehatch and hatch Core20ASV, dominated the Enterobacteriaceae niche and total microbiota in the chick pad feces in the post-hatch area of the hatchery, and the presence of this Salmonella ASV in the post-hatch feces was associated with swabs of breakroom tables. These findings highlight the complexity of commercial hatchery microbiota, including identifying chick pad feces and breakroom tables as potentially important sampling or disinfection targets for hatchery managers to focus their Salmonella mitigation efforts to reduce loads entering live production farms.

Salmonella Biomapping of a Commercial Broiler Hatchery.

Poultry-associated salmonellosis results in significant costs to poultry producers and consumers. Given the vertically integrated nature of the United States poultry industry, a better understanding of Salmonella ecology throughout all levels of poultry production is essential. One nexus point is the hatchery, where eggs from multiple broiler breeder farms are incubated and hatched, with the chicks being sent to numerous farms; therefore, the hatchery represents an ideal area to understand preharvest Salmonella ecology and flow. To achieve this, a commercial broiler hatchery was biomapped, focusing on Salmonella prevalence and serotype diversity among four major sample type categories (Air, Egg, Water, Facility) across five different places in the prehatch, hatch, and posthatch areas. Following two sets of eggs from broiler breeder farms over two production days, the overall Salmonella prevalence was 26% (48/184). Of the positive samples, the highest prevalence was observed in swabs taken from the floor drains in the facility and transport truck (56%), as well as in the hatch and posthatch hatchery areas (50%). Kentucky (n = 17), Gaminara (n = 12), and Alachua (n = 11) were the dominant Salmonella serotypes, with serotypes of greatest outbreak concern from chickens (Enteritidis) representing only 6.25% (3/48) of all recovered Salmonella isolates. The posthatch transport area, including the underfloor reservoirs of the transport trucks, not only harbored Enteritidis but also the enrichment broths from these Salmonella-positive samples also possessed sequences matching the commercial live-attenuated vaccine Typhimurium strain according to CRISPR SeroSeq analyses. These findings highlight the complex diversity of commercial hatchery Salmonella populations, including identifying facility floor drains and transport trucks as potentially important critical control points for hatchery managers to focus their Salmonella mitigation efforts to reduce loads and serotypes entering live production farms.

Salmon hatchery strays can demographically boost wild populations at the cost of diversity: quantitative genetic modelling of Alaska pink salmon.

Hatcheries are vital to many salmon fisheries, with inherent risks and rewards. While hatcheries can increase the returns of adult fish, the demographic and evolutionary consequences for natural populations interacting with hatchery fish on spawning grounds remain unclear. This study examined the impacts of stray hatchery-origin pink salmon on natural population productivity and resilience. We explored temporal assortative mating dynamics using a quantitative genetic model that assumed the only difference between hatchery- and natural-origin adults was their return timing to natural spawning grounds. This model was parameterized with empirical data from an intensive multi-generational study of hatchery-wild interactions in the world's largest pink salmon fisheries enhancement program located in Prince William Sound, Alaska. Across scenarios of increasing hatchery fish presence on spawning grounds, our findings underscore a trade-off between demographic enhancement and preservation of natural population diversity. While enhancement bolstered natural population sizes towards local carrying capacities, hatchery introgression reduced variation in adult return timing by up to 20%. Results indicated that hatchery-origin alleles can rapidly assimilate into natural populations, despite the reduced fitness of hatchery fish attributable to phenotypic mismatches. These findings elucidate the potential for long-term demographic and evolutionary consequences arising from specific hatchery-wild interactions, emphasizing the need for management strategies that balance demographic enhancement with the conservation of natural diversity.

Revolutionizing poultry hygiene: advanced electrostatic and cold fog disinfection strategies combat Mycoplasma gallisepticum in hatching eggs.

The incidence of chronic respiratory disease (CRD) due to Mycoplasma gallisepticum (MG) contamination in hatching eggs poses a serious threat to poultry health and hatchability. Implementing effective sanitization methods while safeguarding the hatching potential of embryos is crucial. This study aimed to explore novel techniques for sanitizing hatching-fertile eggs to prevent and manage MG-associated CRD. The primary objective was to assess the efficacy of acidic electrochemically stimulated water (ECS), focusing on MG disinfection. Additionally, the study investigated 2 application methods, 1) electrostatic disinfection (ED) and 2) cold fog (CF) disinfection, to evaluate their bactericidal effects against MG-contaminated eggs. Deliberately infected MG strains were used for the experimental design, which compared the disinfection efficacy of ECS with its acidic properties. The comparison involved ED, which applies an electrostatic charge to water particles, and CF disinfection, a cold mist technique. Both methods aimed to target MG without compromising egg-hatching potential. The results indicated a significant (p < 0.05) reduction in colony-forming units per milliliter (CFU/mL). However, both application methods demonstrated distinct bactericidal effects. Eggs treated with electrostatic disinfection showed a significant (p < 0.001) reduction in embryonic mortality during incubation (10%) compared to control untreated eggs (18%). Similarly, the CF method exhibited a significant (p < 0.001) decrease in embryonic mortality (13%). The ECS potential in reducing embryonic mortality within the pH range of 2.5 to 6.5 was noted. Both the ED and CF methods show promise for preventing MG-induced hatchery infection while maintaining egg-hatching potential. This study presents innovative techniques to control MG in hatching eggs, contributing to improved poultry health and reduced CRD incidence.

Detection and genetic characterization of chicken astrovirus and avian nephritis virus from hatchery to farm.

RESEARCH HIGHLIGHTS: Identified the role of the hatchery in astrovirus transmission.Sequenced the avian nephritis virus complete genome.Investigated tissue distribution of astrovirus from egg to chicks.Demonstrated co-infection of ANV/CAstV.

Recent insights into egg quality and larval vitality of the European eel Anguilla anguilla.

To date, the eel industry still depends on wild-caught juveniles that are grown to marketable size. There is an urgent need to close the eel life cycle in captivity to make aquaculture independent of the natural population. With this artificial reproduction protocol, yolk-sac larvae can be produced but egg quality may be impaired. Low survival rates and high deformity rates are frequently observed during the first week after hatching. Over the past four years, we have conducted studies with the aim to optimize the artificial reproduction protocol, thereby focussing on increasing egg and larval quality. Weekly carp or salmon pituitary extract (PE) treatment was successfully replaced with recombinant gonadotropins (rGTHs) to mature female eels and produce larvae. 17α,20ß-dihydroxy-4-pregnen-3-one (DHP) was replaced with upstream precursor progesterone (P) to induce the endogenous production of DHP by the female eel. DHP and P were found equally potent in inducing oocyte maturation and ovulation. The effects of antibiotics on larval survival and the occurrence of deformities were investigated. Antibiotic treatment increased survival and decreased the occurrence of deformities indicating bacterial infection as an important cause. A deformity determination key for young eel larvae has been developed that provides a framework of reference for larval deformities which will be instrumental with gaining insights on the reasons behind each larval deformity. These improvements of the artificial reproduction protocol and hatchery practices will contribute to the production of robust eel larvae that survive, grow and metamorphose into juveniles that will later be able to reproduce in captivity.

Hatchery Losses in Flocks of Layer and Broiler Breeders Due to Feed Contamination with Nicarbazin and Narasin: A Case Report.

In the current study, we investigated decreased hatchability and increased embryonic mortality in two farms of layer breeders (flocks A1 and B1) and a farm of broiler breeders (flocks C1 and C2) from Austria, which also presented discoloration of eggshells in 2% of the eggs. After conducting clinical evaluations and the approval that the feed operator was common for flocks A1 and B1, and C1 and C2, it was decided to investigate the feed. Our findings revealed that the feed contained levels of nicarbazin and narasin up to five and 14 times, respectively, above the maximum limits allowed by the European Union for nontarget species. On the other hand, there were no significant abnormalities in vitamin levels, which were also described as the etiology of the noticed abnormalities. Switching to a noncontaminated feed resulted in the clinical signs and production parameters returning to expected ranges. This report emphasizes the significance of considering feed contamination by nicarbazin and narasin as a potential cause of hatchery losses in nontarget species, even in the absence of other clinical signs.

Reporte de caso- Pérdidas en la eclosión de parvadas de reproductoras ponedoras y pollos de engorde debido a la contaminación del alimento con nicarbazina y narasina: Reporte de un caso. En el presente estudio, se investigó la disminución de la incubabilidad y el aumento de la mortalidad embrionaria en dos granjas de reproductoras ponedoras (parvadas A1 y B1) y una granja de reproductoras de pollos de engorde (parvadas C1 y C2) de Austria, que también presentaron decoloración del cascarón en el 2% de los huevos. Luego de realizar evaluaciones clínicas y la aprobación de que el operador de alimento era común para las parvadas A1 y B1, y C1 y C2, se decidió investigar el alimento. Nuestros hallazgos revelaron que el alimento contenía niveles de nicarbazina y narasina de hasta cinco y 14 veces, respectivamente, por encima de los límites máximos permitidos por la Unión Europea para especies no objetivo. Por otro lado, no se observaron anomalías significativas en los niveles de vitaminas, lo que también se describió como la etiología de las anomalías observadas. El cambio a un alimento no contaminado provocó que los signos clínicos y los parámetros de producción regresaran a los rangos esperados. Este informe enfatiza la importancia de considerar la contaminación del alimento por nicarbazina y narasina como una causa potencial de pérdidas en la eclosión de especies no objetivo, incluso en ausencia de otros signos clínicos.

Selection among critically endangered landlocked salmon (Salmo salar m. sebago) families in survival and growth traits across early life stages and in different environments.

Endangered wild fish populations are commonly supported by hatchery propagation. However, hatchery-reared fish experience very different selective pressures compared to their wild counterparts, potentially causing genotype-by-environment interactions (G × E) in essential fitness traits. We experimentally studied early selection in a critically endangered landlocked Atlantic salmon population, first from fertilization to the swim-up stage in a common hatchery setting, and thereafter until the age of 5 months in two contrasting rearing environments. Swim-up progeny were moved either to standard indoor hatchery tanks involving conventional husbandry or to seminatural outdoor channels providing only natural food. After the first summer, sampled survivors were assigned to their families by genotyping. Early survival until the swim-up stage was mostly determined by maternal effects, but also involved significant variation due to sires and full-sib families (potential genetic effects). High on-growing survival in hatchery tanks (88.7%) maintained a more even distribution among families (relative share 1.5%-4.2%) than the seminatural environment (0.0%-5.4%). This heterogeneity was mostly maternal, whereas no independent paternal effect occurred. Heritability estimates were high for body size traits in both environments (0.62-0.69). Genetic correlations between the environments were significantly positive for body size traits (0.67-0.69), and high body condition in hatchery was also genetically linked to rapid growth in the seminatural environment (0.54). Additive and phenotypic growth variation increased in the seminatural environment, but scaling effects probably played a less significant role for G × E, compared to re-ranking of genotypes. Our results suggest that not only maternal effects, but also genetic effects, direct selection according to the environmental conditions experienced. Consistently high genetic variation in growth implies that, despite its low overall genetic diversity and long history in captive rearing (>50 years), this landlocked Atlantic salmon population still possesses adaptive potential for response to change from hatchery rearing back to more natural conditions.

Comparing the migration behavior and survival of Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) smolts.

Many organisms rely on migrations between habitats to maximize lifetime fitness, but these migrations can be risky due to a suite of factors. In anadromous salmonids, the smolt migration from fresh water to sea is a critical life stage, during which smolts can experience high mortality from multiple sources. This study investigated the migratory behavior and survival of Atlantic salmon (Salmo salar) and anadromous brown trout (Salmo trutta) smolts during their seaward migration using acoustic telemetry between March and May 2021. Due to the extinction of wild salmon in the River Gudenaa after the construction of the Tange hydropower plant, this study used hatchery-reared salmon originating from a nearby Danish river. A total of 75 hatchery-reared salmon smolts, 75 hatchery-reared trout smolts, and 75 wild trout smolts were tagged with acoustic transmitters and released into River Gudenaa, Denmark. The downstream movements of tagged fish were monitored using acoustic receivers deployed in the river and fjord. Hatchery-reared trout initiated migration first, followed by hatchery-reared salmon, with wild trout being the last to migrate. There was no difference in riverine progression rates among the three smolt groups, but noticeable differences emerged once in the fjord: trout (wild and hatchery) slowed down, whereas hatchery-reared salmon maintained their speed. Riverine migration was predominantly nocturnal for all smolts; however, daytime migration increased at the fjord arrays. Day-of-year significantly influenced diurnal patterns in the river and fjord, where daytime migration increased later in the year. Hatchery-reared salmon and wild trout had reasonably good overall survival from river to sea entry (≥66%), whereas hatchery-reared trout had poor survival (c.26%). The fjord was the major bottleneck for survival of hatchery-reared trout. We found no strong evidence for differences in progression rate or diurnal patterns between wild and hatchery-reared trout to explain the lower survival. This study demonstrates that salmon and trout differ in their life-history strategy already in the post-smolt phase, and that stocking is a sub-optimal strategy to aid wild populations.

Effects of in ovo vaccination time on broiler performance parameters under field conditions.

Hatchery performance is often evaluated based on descriptors such as hatchability, 7-d mortality, and cost. In addition to these descriptors, it is useful to include in this analysis aspects of chick quality through post-hatch performance. Realizing the bird's complete genetic potential necessitates meeting various criteria, with effective support for the chick's immune system being among the pivotal factors. To be effective, in ovo vaccination systems must deliver the vaccines to specific sites in the egg, a circumstance that directly depends on when the injection is made. We examined production data to evaluate the impact of in ovo vaccination time on performance parameters of male Ross308AP chicks. A comprehensive survey was conducted examining records from 3,722 broiler flocks produced and raised by the same company under standard nutrition and management conditions. The selected data specifically pertained to flocks that underwent slaughter between 41 and 45 d. In our analysis, 4 different linear models were built, one for each response variable: mean weight (MW), body weight gain (BWG), corrected feeding conversion rate (cFCR), and total mortality (TM). The linear models used in the analyses included as main predictor the timing of in ovo vaccination (440, 444, 448, 452, 456, 458, and 460 h of incubation), and as additional predictors: age of the breeding flock (26-35, 36-55 and 56-66 wks old), slaughter age, identity of the hatchery, and the season at which the data was collected. Our results showed that the timing of in ovo vaccination significantly affected BWG and cFCR, with procedures performed at 460 h of incubation showing the best outcomes. Breeding flock age affected all response variables, with older breeding flocks delivering increased MW, BWG and TM, and middle-aged flocks increased cFCR. Increasing slaughter age reduced BWG while MW, cFCR and TM were all increased. These data emphasize the benefits of performing in ovo vaccination as close as possible to 460 h of incubation to extract the best BWG and cFCR from Ross308AP male broiler.

Draft genome sequence of Bacillus velezensis strain 3TSA-3, a potential probiotic for Pacific white shrimp Penaeus vannamei postlarvae isolated from commercial hatchery tanks.

We report the draft genome of Bacillus velezensis strain 3TSA-3, isolated from Pacific white shrimp Penaeus vannamei postlarvae collected from a hatchery tank with high survival despite the presence of pathogenic Vibrio. The strain possesses genes encoding bacteriocins and lacks virulence factor genes, characteristics for a potential aquaculture probiotic.

Hatchery and Dietary Application of Synbiotics in Broilers: Performance and mRNA Abundance of Ileum Tight Junction Proteins, Nutrient Transporters, and Immune Response Markers.

This study investigated the effects of a synbiotic consisting of inulin, Enterococcus faecium, Pediococcus acidilactici, Bifidobacterium animalis, and Lactobacillus reuteri given orally to day (d)-of-hatch (DOH) broiler chicks at the hatchery and in the feed for a 21 d period. A total of 480 Cobb male broilers were randomly divided into one of four treatments using a 2 × 2 factorial design as follows: (1) control (CTRL) group receiving a gel-only oral application on DOH at the hatchery prior to transport and a non-medicated basal corn/soybean meal starter diet; (2) hatchery synbiotic (HS) receiving an oral gel containing the synbiotic (0.5 mL/bird) at the hatchery and the basal diet; (3) CTRL + dietary synbiotic at 0.5 kg/MT (DS); and (4) HS + dietary synbiotic at 0.5 kg/MT (HSDS). On d 7 and d 21, one bird per pen (eight replicate pens/group) was euthanized, and the ileum was immediately removed for qPCR analysis. Data were subjected to a 2-way ANOVA using GLM procedure (JMP Pro17). A significant diet × hatchery interaction was observed in feed conversion ratio (FCR) from d 14 to d 21 (p = 0.013) where the HS, DS, and HSDS treatments had a significantly lower FCR compared to the CTRL. However, no significant interaction effect was observed for body weight gain (BWG) or FCR during the overall experimental period. No significant interaction was observed in mRNA abundance of the evaluated genes in the ileum on d 7 and d 21. Gel application with the synbiotic significantly reduced sodium-dependent glucose cotransporter 1 (SGLT1) mRNA abundance on d 7 (p = 0.035) in comparison to birds receiving gel alone. Regardless of hatchery application, dietary synbiotic supplementation significantly reduced Toll-like receptor (TLR)2, TLR4, and interleukin (IL)-10 mRNA abundance on d 7 (p = 0.013). In conclusion, these findings showed that hatchery and dietary synbiotic application could have a potential beneficial impact on broiler intestinal immunity by regulating the TLR response, a key element of innate immunity. FCR was improved from d 14 to d 21 after synbiotic application. Future research involving extended grow-out studies with a disease challenge would expand on the implications of an early application of synbiotics.

The impact of dissolved oxygen concentration on the swimming performance and welfare of ballan wrasse (Labrus bergylta Ascanius, 1767).

Sea lice (Lepeophtheirus salmonis [Krøyer, 1838]) are a key issue for salmon aquaculture, contributing to increased mortality for both wild and farmed salmon if no action is taken. Using cleaner fish can be an effective, drug-free treatment method, and ballan wrasse (Labrus bergylta) is a hardy wrasse species that displays cleaning behavior. With concerns about the overharvest of wild ballan wrasse, many companies farm this species, but the optimal ranges of a wide variety of rearing parameters are still unknown. This study investigated the effect of 6-week exposure to four dissolved oxygen (DO) levels (125%, 100%, 85%, and 75% DO saturation as the percentage of air) on ballan wrasse. Survival; growth (specific growth rate, SGR); condition factor (CF); and primary (cortisol), secondary (glucose, lactate, magnesium), and tertiary stress indicators (swimming performance) were investigated. There were no differences in SGR, CF, survival, or cortisol level among the groups at the end of the 6 weeks. There was variation in the magnitude of the cortisol response to an acute stressor at the end of the 6-week period, with the 75% DO treatment exhibiting a 3.3-fold increase in cortisol compared to a 5.2-fold increase in the control group (100%), which could suggest chronic stress. Relative critical swimming speed (RUcrit) was measured to investigate swimming performance once all groups were returned to 100% DO saturation. The 75% RUcrit was lower than the 100% treatment (1.7 ± 0.18 body length [BL]/s compared to 2.5 ± 0.16 BL/s). Overall, these results suggest that DO levels of 75% trigger physiological changes and therefore may negatively affect welfare.

Invasion status of hatchery-origin pink salmon in an unstocked river at the Shiretoko World Natural Heritage Site in northern Japan.

Hatchery fish and their offspring (including hatchery-wild hybrids) have lower reproductive success than wild fish. Thus, the straying of hatchery fish may negatively impact wild populations, depending on the number of wild salmon returning and hatchery strays. We investigated the straying status of hatchery-origin pink salmon (Oncorhynchus gorbuscha), which have a higher straying rate than other salmonids, in an unstocked river at the Shiretoko World Natural Heritage Site, Japan. The hatchery strays accounted for 40.0% and 19.0% of the total samples in 2021 and 2022, respectively. These results indicate that hatchery pink salmon have invaded unstocked rivers and potentially genetically affect wild populations.

Utility of parentage-based tagging for monitoring Coho salmon (Oncorhynchus kisutch) in the interior Columbia River basin.

By the 1980s, after decades of declining numbers in the mid-1900s, Coho salmon (Oncorhynchus kisutch) were considered extirpated from the interior Columbia River. In the mid-1990s, the Confederated Tribes of the Umatilla Indian Reservation, the Confederated Tribes and Bands of the Yakama Nation, and the Nez Perce Tribe began successful reintroduction programs of Coho salmon upstream of Bonneville Dam, but which were initially sourced from lower Columbia River hatcheries. Here we present the first Coho salmon parentage-based tagging (PBT) baseline from seven hatchery programs located in the interior Columbia River basin, and two sites at or downstream of Bonneville Dam, composed of over 32,000 broodstock samples. Analyses of baseline collections revealed that genetic structure followed a temporal pattern based on 3-year broodlines rather than geographic location or stocking history. Across hatchery programs, similar levels of genetic diversity was present. The PBT baseline provided multiple direct applications such as identification of origin for Coho salmon collected in a mixed stock at Priest Rapids Dam and the detection of the proportion and distribution of hatchery-origin fish on the spawning grounds in the Methow River basin. The PBT baseline for Coho salmon is freely available for use and can be downloaded from FishGen.net.

Genomic evidence for domestication selection in three hatchery populations of Chinook salmon, Oncorhynchus tshawytscha.

Fish hatcheries are widely used to enhance fisheries and supplement declining wild populations. However, substantial evidence suggests that hatchery fish are subject to differential selection pressures compared to their wild counterparts. Domestication selection, or adaptation to the hatchery environment, poses a risk to wild populations if traits specific to success in the hatchery environment have a genetic component and there is subsequent introgression between hatchery and wild fish. Few studies have investigated domestication selection in hatcheries on a genomic level, and even fewer have done so in parallel across multiple hatchery-wild population pairs. In this study, we used low-coverage whole-genome sequencing to investigate signals of domestication selection in three separate hatchery populations of Chinook salmon, Oncorhynchus tshawytscha, after approximately seven generations of divergence from their corresponding wild progenitor populations. We sequenced 192 individuals from populations across Southeast Alaska and estimated genotype likelihoods at over six million loci. We discovered a total of 14 outlier peaks displaying high genetic differentiation (F ST) between hatchery-wild pairs, although no peaks were shared across the three comparisons. Peaks were small (53 kb on average) and often displayed elevated absolute genetic divergence (D xy) and linkage disequilibrium, suggesting some level of domestication selection has occurred. Our study provides evidence that domestication selection can lead to genetic differences between hatchery and wild populations in only a few generations. Additionally, our data suggest that population-specific adaptation to hatchery environments likely occurs through different genetic pathways, even for populations with similar standing genetic variation. These results highlight the need to collect paired genotype-phenotype data to understand how domestication may be affecting fitness and to identify potential management practices that may mitigate genetic risks despite multiple pathways of domestication.

Characterization of hatchery residues for on farm implementation of circular waste management practices.

The conventional management of hatchery residues is associated with greenhouse gas and unpleasant odor emissions, the presence of pathogens and high disposal costs for producers. To address these issues, on-farm alternatives like composting, fermentation, and insect valorization are promising approaches. This study aims to characterize hatchery residues and define critical quality thresholds to identify effective processes for their management. Hatchery residue samples were collected bi-monthly over a year (N = 24) and were analyzed for proximate composition (dry matter, ash, energy, crude protein, crude lipid, crude fiber, carbohydrates), pH, color (L*a*b*, Chroma) and microbiological loads (total aerobic mesophilic counts, coliforms, lactic acid bacteria). Volatile fatty acid composition was also measured (N = 8). Significant correlation coefficients were found between TAM and LAB loads and residue characterization (pH, chroma, crude fibers, carbohydrates, and temperature). On a dry matter basis, residues were high in energy (2498 to 5911 cal/g), proteins (21.3 to 49.4 %) and lipids (14.6 to 29.1 %), but low in carbohydrates (0 to 15.3 %) despite temporal fluctuations. Ash content varied widely (8.6 to 49.1 %, dry matter) and is influenced by eggshell content. Microbiological loads were high for total aerobic mesophilic bacteria (6.5 to 9.1 log cfu/g), coliforms (5.4 to 8.5 log cfu/g) and lactic acid bacteria (6.7 to 9.0 log cfu/g). Valorization of hatchery residues on the farm will depends on the optimization of effective upstream stabilization processes. The critical points are discussed according to the valorization potentials that could be implemented on the farm from composting to upcycling by insects.

Influence of Pediveliger Larvae Stocking Density on Settlement Efficiency and Seed Production in Captivity of Mytilus galloprovincialis in Amsa Bay, Tetouan.

In mussel hatchery systems, the settlement process is a crucial element influencing seed yield. The current study assayed the influence of five densities of competent pediveliger larvae on settlement success and post-larvae production. We showed an inverse relationship between density and settlement efficiency, e.g., an attachment success of 99.4% at the lowest density (35 larvae/cm2) but only 9% at the highest density (210 larvae/cm2). However, post-larvae production was higher at intermediate larvae densities (70 larvae/cm2). The reimplementation of treatments upon post-larvae density after 6 weeks post settlement showed that the lowest-density groups bore both the highest post-larvae growth rate (22.24 ± 4.60 µm/day) and the largest head batch (48% of the size distribution), as compared to the higher-post-larvae-density groups. These results highlight the importance of optimizing both pediveliger larvae density and post-larvae density, to maximize high-quality seed yield in local hatcheries. Current rearing technologies would assure a timely commercial seed production to protect natural sea rocky beds in Alboran Sea coasts.

Achieving conservation and restoration outcomes through ecologically beneficial aquaculture.

A range of conservation and restoration tools are needed to safeguard the structure and function of aquatic ecosystems. Aquaculture, the culturing of aquatic organisms, often contributes to the numerous stressors that aquatic ecosystems face, yet some aquaculture activities can also deliver ecological benefits. We reviewed the literature on aquaculture activities that may contribute to conservation and restoration outcomes, either by enhancing the persistence or recovery of one or more target species or by moving aquatic ecosystems toward a target state. We identified 12 ecologically beneficial outcomes achievable via aquaculture: species recovery, habitat restoration, habitat rehabilitation, habitat protection, bioremediation, assisted evolution, climate change mitigation, wild harvest replacement, coastal defense, removal of overabundant species, biological control, and ex situ conservation. This list may be expanded as new applications are discovered. Positive intentions do not guarantee positive ecological outcomes, so it is critical that potentially ecologically beneficial aquaculture activities be evaluated via clear and measurable indicators of success to reduce potential abuse by greenwashing. Unanimity on outcomes, indicators, and related terminology will bring the field of aquaculture-environment interactions into line with consensus standards in conservation and restoration ecology. Broad consensus will also aid the development of future certification schemes for ecologically beneficial aquaculture.

Se necesita una gama de herramientas de conservación y restauración para salvaguardar la estructura y función de los ecosistemas acuáticos. La acuacultura (el cultivo de organismos acuáticos) generalmente contribuye a los numerosos estresantes que soportan los ecosistemas acuáticos, aunque algunas actividades de la acuacultura también pueden proporcionar beneficios ecológicos. Revisamos la literatura sobre las actividades de acuacultura que pueden contribuir a los resultados de conservación y restauración, ya sea al incrementar la persistencia o recuperación de una o más especies objetivo o al llevar a los ecosistemas acuáticos hacia un estado objetivo. Identificamos doce resultados con beneficios ecológicos que pueden lograrse con la acuacultura: recuperación de la especie, recuperación del hábitat, restauración del hábitat, rehabilitación del hábitat, protección del hábitat, bioreparación, evolución asistida, mitigación del cambio climático, sustitución de la captura silvestre, defensa costera, eliminación de las especies sobreabundantes, control biológico y conservación ex situ. Esta lista puede expandirse conforme se descubren nuevas aplicaciones. Las intenciones positivas no garantizan resultados ecológicos positivos, así que es importante que se evalúen las actividades de acuacultura con un posible beneficio ecológico por medio de indicadores del éxito claros y medibles para reducir el abuso potencial por ecoblanqueo o greenwashing. La unanimidad en los resultados, indicadores y terminología relacionada armonizará las interacciones entre la acuacultura y el ambiente con los estándares de la conservación y la ecología de la restauración. Un consenso generalizado también ayudará con el desarrollo de futuros esquemas de certificación para la acuacultura con beneficios ecológicos. Obtención de resultados de conservación y restauración a través de la acuacultura con beneficios ecológicos.

Infection status of masu salmon Oncorhynchus masou by the parasite Salmonema cf. ephemeridarum (Nematoda, Cystidicolidae).

Nematodes that parasitize salmonids are found in both seawater and freshwater. Unlike seawater species such as those in family Anisakidae, freshwater species have not been well studied. In particular, the influences of these nematodes on the body condition of salmonids remain unclear. We studied the effects of Salmonema cf. ephemeridarum on the body condition of masu salmon Oncorhynchus masou. We found a positive relationship between the number of parasites and fish fork length. In contrast, we found a negative relationship between the body condition (condition factor) of fish and the number of parasites. These results suggest that nematode infection could affect host energy reserves for future growth.