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Increasing seawater temperatures coupled with more intense and frequent heatwaves pose an increasing threat to marine species. In this study, the New Zealand green-lipped mussel, Perna canaliculus , was used to investigate the effect of genetics and ontogeny on thermal resilience. The culturally and economically significant mussel P. canaliculus (Gmelin, 1971) has been selectively-bred in New Zealand for two decades, making it a unique biological resource to investigate genetic interactions in a temperate bivalve species. Six selectively-bred full sibling families and four different ages, from early juveniles (6, 8, 10 weeks post-fertilisation) to sub-adults (52 weeks post-fertilisation), were used for experimentation. At each age, each family was exposed to a three-hour heat challenge, followed by recovery, and survival assessments. The shell lengths of live and dead juvenile mussels were also measured. Gill tissue samples from sub-adults were collected after the thermal challenge to quantify the 70 kDa heat shock protein gene ( hsp70 ). Results showed that genetics, ontogeny and size influence thermal resilience in P. canaliculus , with LT 50 values ranging between 31.3 and 34.4 °C for all studied families and ages. Juveniles showed greater thermotolerance compared to sub-adults, while the largest individuals within each family/age class tended to be more heat sensitive than their siblings. Sub-adults differentially upregulated hsp70 in a pattern that correlated with net family survival following heat challenge, reinforcing the perceived role of inducible HSP70 protein in molluscs. This study provides insights into the complex interactions of age and genotype in determining heat tolerance of a key mussel species. As marine temperatures increase, equally complex selection pressure responses may therefore occur. Future research should focus on transcriptomic and genomic approaches for key species such as P. canaliculus to further understand and predict the effect of genetic variation and ontogeny on their survival in the context of climate change.

Abstract The occurrence of pathogenic bacteria has emerged as a plausible key component of summer mortalities in mussels. In the current research, four bacterial isolates retrieved from moribund Greenshell࣪ mussels, Perna canaliculus, from a previous summer mortality event, were tentatively identified as Vibrio and Photobacterium species using morpho-biochemical characterization and MALDI-TOF MS and confirmed as V. celticus, P. swingsii, P. rosenbergii, and P. proteolyticum using whole genome sequencing. These isolates were utilized in a laboratory challenge where mussels were injected with cell concentrations ranging from 105 to 109 CFU/mussel. Of the investigated isolates, P. swingsii induced the highest mortality. Additionally, results from quantitative polymerase chain reaction analysis, focusing on known virulence genes were detected in all isolates grown under laboratory conditions. Photobacterium rosenbergii and P. swingsii showed the highest expression levels of these virulence determinants. These results indicate that Photobacterium spp. could be a significant pathogen of P. canaliculus, with possible importance during summer mortality events. By implementing screening methods to detect and monitor Photobacterium concentrations in farmed mussel populations, a better understanding of the host–pathogen relationship can be obtained, aiding the development of a resilient industry in a changing environment. Bacterial strains were isolated from summer mortality events in moribund Greenshell࣪ mussels, and one of these, Photobacterium swingsii was found for the first time to cause the highest mortality in mussels (P. canaliculus) in a controlled experiment.

Nursery culture can improve the efficiency of mussel aquaculture by reducing the high losses of spat and overcoming inconsistencies in wild‐spat supplies. The success of nursery systems depends on the availability of unattached single or singulated spat, which requires the separation of spat from their associated settlement substrates (i.e., singulation). This study investigated whether sub‐lethal environmental stressors could facilitate the singulation of Greenshell mussels (Perna canaliculus) spat from their attachment to collector ropes. Segments of spat‐collector ropes were exposed to stressors consisting of either high (45 ppt) or low (25 ppt) salinity for 2 h, periods of emersion (air exposure) for 2 or 4 h, or combinations of reduced aeration and limited food availability for 12 h. Spat singulated from the collector rope were returned to clean seawater and reared for 24 h, after which their survival rates were measured. The results indicated that up to 80% of spat could be singulated from the ropes after a 12 h exposure to seawater with no aeration and no food (i.e., NA‐NF). However, although survival rates following singulation ranged from 60% to 90% across treatments, overall recovery of viable, unattached spat was lower, reaching a maximum of 65% relative to the initial number of settled spat. Singulation efficacy was influenced by treatment and spat size, with smaller spat (< 3.5 mm) more easily singulated than larger ones (> 5 mm). Variations in the spat responses to the stressors indicate a need for further research to optimise singulation techniques and better understand the mechanisms driving the attachment and detachment responses in the mussel spat. Regardless, the study demonstrates that up to 65% of viable spat can be effectively removed from collector ropes using environmental stressors, making them readily available for rearing in nursery systems and reducing spat losses from production.

Pulmonary hypertension (PH) in dogs, characterized by abnormally high blood pressure in the pulmonary arteries, presents a management challenge, and adjunctive therapies for the standard treatment of sildenafil are needed. This study aimed to determine whether the nutraceutical Perna canaliculus oil (PCSO-524), a marine lipid extract with anti-inflammatory properties, provides additional clinical benefits to dogs with PH. In a prospective, randomized, placebo-controlled trial, seventeen client-owned dogs diagnosed with PH were assigned to receive either PCSO-524 or a placebo as an add-on to their sildenafil-based therapy for 70 days. Key outcomes were evaluated using owner-assessed clinical scores for exercise tolerance and coughing, alongside echocardiographic measurements. The PCSO-524 group demonstrated a statistically significant improvement in exercise tolerance scores by day 70 (P = 0.009). This group also showed a greater reduction in coughing scores compared to the placebo group between day 35 and day 70 (P = 0.03). While the tricuspid regurgitation pressure gradient (TRPG), an estimate of pulmonary pressure, decreased significantly over time in all dogs (P = 0.001), no significant difference was found between the groups for this specific measure. These results indicate that PCSO-524 can serve as a beneficial adjunctive therapy for improving important clinical signs, such as exercise tolerance and coughing, in dogs with PH. This suggests it may be a valuable addition to standard management for enhancing quality of life.

Poor health and mortality events of the commercially important and endemic New Zealand green-lipped mussel (Perna canaliculus) pose a threat to its industry. Despite the known importance of microbiomes to animal health and environmental resilience, the host-associated microbiome is unexplored in this species. We conducted the first baseline characterization of bacteria and fungi within key host tissues (gills, haemolymph, digestive gland, and stomach) using high-throughput amplicon sequencing of 16S rRNA gene and ITS1 region for bacteria and fungi, respectively. Tissue types displayed distinctive bacterial profiles, consistent among individuals, that were dominated by phyla which reflect (1) a fluid exchange between the circulatory system (gills and haemolymph) and surrounding aqueous environment and (2) a highly diverse digestive system (digestive gland and stomach) microbiota. Gammaproteobacteria and Campylobacterota were mostly identified in the gill tissue and haemolymph, and were also found in high abundance in seawater. Digestive gland and stomach tissues were dominated by common gut bacterial phyla, such as Firmicutes, Cyanobacteria, Proteobacteria, and Bacteroidota, which reflects the selectivity of the digestive system and food-based influences. Other major notable taxa included the family Spirochaetaceae, and genera Endozoicomonas, Psychrilyobacter, Moritella and Poseidonibacter, which were highly variable among tissue types and samples. More than 50% of fungal amplicon sequence variants (ASVs) were unclassified beyond the phylum level, which reflects the lack of studies with marine fungi. However, the majority of those identified were assigned to the phylum Ascomycota. The findings from this work provide the first insight into healthy tissue microbiomes of P. canaliculus and is of central importance to understanding the effect of environmental changes on farmed mussels at the microbial level.

The marine environment is ever-changing, with daily and seasonal variations in factors such as food availability and seawater temperature. These stressors can affect physiological processes in aquatic organisms, resulting in sub-lethal or lethal consequences. This study assessed the effects of food limitation (i.e. fasting) on heat-stress responses in juveniles (∼1.3 mm in shell length) of the green-lipped mussel Perna canaliculus. Fasting for up to 24 h did not have a significant effect on oxidative damage (protein carbonyls and lipid hydroperoxide accumulation) or the activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase) after exposure to heat stress. However, fasting for 54 h and subsequent heat stress resulted in increased oxidative damage and decreased activity of antioxidant enzymes in juvenile mussels. Gene expression of 70 kDa heat shock protein (hsp70) was only significantly affected by heat shock, not nutritional status. Tissue carbohydrate and protein levels were significantly depleted by 54 h of fasting; as these proximate components represent key energy substrates for bivalves, it is suggested that energy limitation contributes to compromised antioxidant activity and predisposition to oxidative damage.

Vibrio coralliilyticus is a bacterial pathogen which can affect a range of marine organisms, such as corals, fish and shellfish, with sometimes devastating consequences. However, little is known about the mechanisms involved in the host-pathogen interaction, especially within molluscan models. We applied gas chromatography-mass spectrometry (GC-MS)-based metabolomics to characterize the physiological responses in haemolymph of New Zealand Greenshell™ mussels (Perna canaliculus) injected with Vibrio sp. DO1 (V. coralliilyticus/neptunius-like isolate). Univariate data analyses of metabolite profiles in Vibrio-exposed mussels revealed significant changes in 22 metabolites at 6 h post-infection, compared to non-exposed mussels. Among them, 10 metabolites were up-regulated, while 12 metabolites were down-regulated in infected mussels. Multivariate analyses showed a clear distinction between infected and non-infected mussels. In addition, secondary pathway analyses indicated perturbations of the host innate immune system following infection, including oxidative stress, inflammation and disruption of the TCA cycle, change in amino acid metabolism and protein synthesis. These findings provide new insights into the pathogenic mechanisms of Vibrio infection of mussels and demonstrate our ability to detect detailed and rapid host responses from haemolymph samples using a metabolomics approach.

The onset of the Anthropocene has coincided with enormous global declines in natural ecosystems, leading to losses in the valuable goods and ecosystem services they provide. This global decline, in conjunction with growing recognition of the ecological importance of natural ecosystems, has generated a pressing need for restoration. Effective ecosystem restoration relies on accurate identification of the cause of decline and clear metrics of success, which are only possible with baseline data of both the pre‐degradation and pre‐restoration ecosystems. However, the establishment of these baselines can be difficult as different potential information sources each have benefits and drawbacks. Determining an efficient method to balance these diverse information sources and generate robust baselines is vital to achieving the United Nations' goal of massively scaled‐up ecosystem restoration. Here we expand on the concept of multidisciplinary baselines, or the combined use of sources and methods across a wide disciplinary spectrum to establish comprehensive and reliable ecosystem baselines, and use mussel reefs in the South Island of New Zealand as a test case. Using a combination of comprehensive historical review, extensive shoreline surveys, and local ecological knowledge, we demonstrate that local mussel abundances decreased by 97% since the mid‐1960s as a result of overharvesting, leaving the extant populations scattered, small, and without recovery. This study demonstrates that harnessing multidisciplinary baselines allows for the consolidation of qualitative and quantitative estimates of ecosystem change over hundreds of years, as well as confirmation of causes of ecosystem degradation, and clear documentation of current ecosystem state beyond what is possible from any individual source. This approach to establishing ecosystem baselines also provides valuable avenues for the advancement of restoration by quantifying the temporal and geographic scales of ecosystem decline, identifying areas for intervention, and establishing clear metrics of success.

Background: The prevalence rate of attention-deficit/hyperactivity disorder (ADHD) within Western cultures is between 5% and 12%, and is the most common psychiatric illness among school-aged children, with an estimated 50% of these children retaining ADHD symptoms for the rest of their lives. Children with ADHD have lower blood levels of long-chain Poly Unsaturated Fatty Acids (LC PUFAs) compared with children without ADHD, and following PUFA supplementation, have shown improvements in ADHD-related symptoms. One highly promising marine based LC PUFA preparation is the Omega-3-rich Lyprinol/Omega XL which is a natural formulation containing standardised lipid extract of the New Zealand green lipped mussel (Perna canaliculus) known as PCSO-524 registered which contains a unique combination of free fatty acids, sterol esters, polar lipids and carotenoids. It is this unique combination of marine lipids that may assist in correcting the decreased levels of LC PUFA levels in children with symptoms of ADHD. The compound is a mixture belonging to a lipid group called sterol esters (SE). The fatty acids in the SE fraction are mainly myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Lyprinol/Omega XL has previously been shown to contain a potent group of Omega-3 lipids that block the 5 - lipoxygenase metabolic pathway responsible for inflammation in the body. Methods: A randomized double blind placebo controlled trial will be utilized to assess the effects of 14 weeks administration of Lyprinol/Omega XL versus placebo in 150 children aged 6 to 14 years with high levels of hyperactivity and inattention. Additionally, a range of cognitive, mood and central electrophysiological measures will be undertaken during the 14 week supplementation trial. The primary outcome measure, the Conners' Parent Rating Scales will be completed initially at baseline, then in weeks 4, 8, 10, 14 and then again at 4 weeks post-administration (week 18). The results will contribute to our understanding of the efficacy of marine based Omega-3 s with high anti-inflammatory actions on inattention and hyperactivity in children aged 6 to 14 years.

The nursery culture of bivalves typically relies on the feeding of costly live microalgae, while the use of natural sources of phytoplankton for feed is uncertain due to their variable quality and abundance. Replacement diets have been applied in bivalve nursery culture to replace live microalgae with varying success. This study investigated the potential use of two concentrated microalgal diets at a range of levels of substitution with live microalgae. Shellfish Diet 1800® (called SD) and LPB™ Frozen Shellfish Diet® (called LPB) were fed to juvenile green-lipped mussels (Perna canaliculus) at five levels of substitution for live microalgae (i.e., 0, 25, 50, 75, and 100%) for 27 days. The mortality of mussels fed with 100% LPB replacement was significantly higher than the mortality of mussels fed at the lower levels of replacement, i.e., 0 and 25%. The overall final size of spat tended to decrease with the increasing level replacement of live microalgae. Proximate analysis (i.e., crude ash-free dry weight, crude protein, crude lipid, and carbohydrate) showed that only the proportion of carbohydrate content of spat was influenced by feeding treatments, with the mean total carbohydrate content of mussels tending to decrease with increasing levels of replacement of live microalgae. The results indicate that both concentrated microalgal feeds (SD and LPB) are effective at replacing live microalgae by up to 50% without compromising the survival and nutritional profile (AFDW, protein, lipid, and carbohydrate content) of juvenile green-lipped mussels and are therefore a useful resource for improving the efficiency of production.