Nelson Marlborough Institute of Technology

In the real-time energy management of offshore islanded microgrids, determining the optimal operating points of storage systems, particularly in hydrogen-based storage, poses significant challenges. These arise from the stochastic nature of offshore Renewable Energy Sources (RES), variable power demand, and the volatility of hydrogen systems. To address these, a novel objective function has been developed that integrates electrolyzer system efficiency into the Energy Management Strategy (EMS) of a DC microgrid. Unlike most existing literature, which considers electrolyzer efficiency as a constant, this work treats efficiency as a dynamic variable that depends on operating current, temperature, and pressure. The behavior of the electrolyzer efficiency with respect to these parameters is modeled, verified, and subsequently incorporated into the EMS. A MINLP based EMS is developed to implement the proposed formulation, and its effectiveness is validated by demonstrating optimal microgrid performance under the above scenario. Notably, the impact of optimal temperature and pressure control is evidenced by electrolyzer efficiency improvements of 1.7% and 3.1% in the efficiency-focused and multi-objective scenarios, respectively. The proposed EMS is evaluated against a rule-based and heuristic (PSO) methods. In the cost-based case, the developed method shows 36.5% and 0.04% cost reductions relative to the rule-based approaches, and a 0.39% reduction relative to PSO. In the efficiency-based scheme, it attains 0.10% efficiency gain over PSO for the optimal temperature-pressure method, and in the multi-objective case, it delivers 7.40% efficiency gain versus PSO. • Novel optimization with electrolyzer efficiency for offshore islanded DC microgrids. • Electrolyzer efficiency modeled dynamically via current, temperature, and pressure. • Multi-objective framework balances cost and efficiency in flexible microgrid EMS. • Sensitivity to electrolyzer operating conditions is analyzed. • EMS validated against rule-based and metaheuristic approaches.

Scientific publishing is widely perceived to be in a state of crisis. A contributing factor is reproducibility: the extent to which the results can be replicated is key to assessing the reliability of a study. Reproducibility rates have often been found to be low, a situation complicated by the fact that many studies provide insufficient details of their methods. For the last decade, we have been using a framework that allows us to fully reproduce the results of analyses of fisheries data. Key features are that the analyses are fully defined in code and run within a consistent computing environment. The approach has proven to be transferable, with the framework being adopted in a range of other disciplines. Incentivising the broader adoption of fully reproducible analyses would assist in re-establishing trust in scientific publications, addressing the "reproducibility crisis" while also providing a basis for strengthened peer review processes and increasing the likelihood that questionable research practices are identified. Implementing fully reproducible analyses has some overhead, especially where the software tools that support the approach are unfamiliar. We have found that the benefits of openness, transparency, and efficiency, together with increased collaboration, make this overhead worthwhile.

ABSTRACT Green‐lipped mussels ( Perna canaliculus ), like other reef building bivalves, are ecosystem engineers that hold considerable importance commercially and culturally. However, natural beds of this endemic species in Aotearoa New Zealand have been decimated through overharvesting and recovery has been almost non‐existent. For restoration purposes, mussels are typically sourced from subtidal aquaculture farms requiring time to allow for successful attachment. This is particularly challenging in exposed environments where dislodgement risk is high and limited research exists. The aim of this field experiment was to investigate the use of cages for different durations to protect and contain adult mussels translocated to a semi‐exposed intertidal site to assess attachment success and survival. Farm‐supplied mussels ( n = 20 per plot) were translocated to plots with no cages, partial cages or full cages for three different durations (i.e., 2, 15 or 29 days; n = 3 plots per treatment). All plots were assessed at 2‐ and 14‐days post cage removal (total experimental period of 46 days). Condition of mussels was also assessed at the start and end of the experiment. The duration of cage containment was shown to be a key factor in attachment success and survival. Results indicated that the longest protection period significantly improved mussel attachment, thereby improving settlement success. A protection period of only two days resulted in ∼98% loss of mussels after 14 days, whereas 29 days of cage protection reduced losses to ∼10%. The condition of mussels at the end of the experiment, however, was reduced compared to deployment. These findings highlight the promising value of using temporary protection during the initial attachment phase of translocated adult mussels and the importance of allowing for an adequate window of opportunity to establish strong byssal attachments to the available substrates. This study provides important insights for future restoration of mussels in semi‐exposed intertidal environments.

In many aquaculture farms, Unmanned Underwater Vehicles (UUVs) are being deployed to perform dangerous and time-consuming repetitive tasks (e.g., fish net-pen visual inspection) on behalf of or in collaboration with farm operators. Mostly, they are remotely operated, and one of the main barriers to deploying them autonomously is the UUV localisation. Specifically, the cost of the localisation sensor suite, sensor reliability in constrained operational workspace and return on investment (ROI) for the huge initial investment on the UUV and its localisation hinder the R&D work and adoption of the autonomous UUV deployment on an industrial scale. The proposed system, which leverages the AprilTag (a fiducial marker used as a frame of reference) detection, provides cost-effective UUV localisation for the initial trials of autonomous UUV deployment, requiring only minor modifications to the aquaculture infrastructure. With such a cost-effective approach, UUV R&D engineers can demonstrate and validate the advantages and challenges of autonomous UUV deployment to farm operators, policymakers, and governing authorities to make informed decision-making for the future large-scale adoption of autonomous UUVs in aquaculture. Initial validation of the proposed cost-effective localisation system indicates that centimetre-level accuracy can be achieved with a single monocular camera and only 10 AprilTags, without requiring physical measurements, in a 115.46 m3 laboratory workspace under various lighting conditions.

Māori, the Indigenous people of Aotearoa/New Zealand, experience enduring inequities across surgical pathways shaped by historical, social, and political factors. This integrative review examined how Māori cultural safety is embedded in surgical care to identify principles for improving Indigenous health outcomes. Peer-reviewed studies published since 2017 were sourced from three databases and appraised using the Critical Appraisal Skills Program (CASP). Eleven studies met inclusion criteria (New Zealand, n = 6; Australia, n = 5). Two overarching themes, institutional racism and models of care, revealed inequities in prehabilitation, primary care access, and referral processes. While culturally centered models improved experiences, limited uptake restricted impact. Findings emphasize the need for system-level transformation to embed cultural safety and equity across surgical pathways. Six guiding principles include grounding initiatives in Māori worldviews, institutional commitment, barrier reduction, cultural training, whānau engagement, and Indigenous-led hospital design to achieve equitable Māori surgical outcomes.

• The energy-optimal Model Predictive Control problem formulation that reflects the real power consumption is proposed. • From theoretical and practical aspects, solving the resulting non-convex optimization in real-time is demonstrated. • The effects of non-convex system-level power function on energy optimization is investigated. • The controllers are tested for real-time feasibility in high-fidelity simulation using ROS and Gazebo taking into account the fish farm and UUV specifications. • The proposed EO-MPC saves 3.1 % - 21.4 % more energy than CO-MPC while achieving better or equivalent trajectory tracking performance under different underwater current disturbance speeds ( 0.0 m / s , 0.5 m / s and 0.9 m / s ). Unmanned underwater vehicles are deployed to automate the production processes in offshore aquaculture, but the onboard power supply with limited energy capacity constrains the operational range and time. In this paper, a nonlinear energy-optimal Model Predictive Control (EO-MPC) is proposed to perform a 4-degree-of-freedom 3D fish net-pen visual inspection trajectory tracking while minimizing energy consumption. The EO-MPC problem with explicit energy-related terms in the performance index (PI) is transcribed into a nonlinear programming problem (NLP), solved via IPOPT, the open-sourced primal-dual interior point solver. Using the specifications of Blue Endeavour Project (the upcoming first-of-its-kind offshore salmon firm in New Zealand) of the New Zealand King Salmon Company and the work-class ROV called RexROV 2, theoretical fundamentals and practical implementation aspects are detailed, and four controllers are tested in high-fidelity simulation using Robot Operating System and Gazebo Physics Engine. In a general constrained operational working environment, the proposed EO-MPC controller saves 3.1 % - 21.4 % more energy than the conventional MPC (CO-MPC) while achieving better or equivalent trajectory tracking performance under different underwater current disturbance speeds ( 0.0 m / s , 0.5 m / s and 0.9 m / s ).

Context Historically, humpback whales migrating past Aotearoa New Zealand (NZ) were linked to western South Pacific wintering grounds and Antarctic feeding grounds. As populations have recovered, research has focused on contemporary connectivity patterns throughout the South Pacific. Aims To determine the contemporary connectivity of winter breeding grounds for humpback whales on their northern and southern migrations past NZ, and those at the Kermadec Islands (Rangitāhua) migratory stopover. Methods We generated DNA profiles (mitochondrial DNA (mtDNA) haplotypes, genetic sex and microsatellite genotypes) using skin samples collected from whales between 1998 and 2021. We used comparisons of DNA profiles and a mixed-stock analysis of mtDNA haplotypes to determine the most likely wintering grounds of genetically identified individuals. Key results DNA profiles of 350 individual whales from NZ were compared to profiles from Oceania (n > 2000), Central and South America (n = 452) and East Australia (n = 809). This comparison revealed 35 genotype matches, mainly to New Caledonia and East Australia. The mixed-stock analysis showed that northbound whales (n = 145) had approximately equal assignment proportions to East Australia and New Caledonia whereas southbound whales (n = 74) showed a two-fold higher assignment to East Australia. In contrast, whales passing Rangitāhua (n = 112) assigned to New Caledonia and other Pacific wintering grounds but not to East Australia. Conclusions Humpback whales passing mainland NZ on their north and southbound migrations are strongly associated with East Australia and New Caledonia wintering grounds. Those migrating south past Rangitāhua have a broader range of wintering ground destinations, including a connection to Central America.