ORCID Profile
0000-0003-4291-6239
Current Organisation
University of Tasmania
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Publisher: Informa UK Limited
Date: 25-02-2023
Publisher: Wiley
Date: 29-04-2016
DOI: 10.1111/OIK.02952
Publisher: Wiley
Date: 2014
DOI: 10.1111/JPC.12446
Publisher: Springer Science and Business Media LLC
Date: 12-08-2023
DOI: 10.1007/S10811-023-03061-5
Abstract: We found that an innovative nursery approach, where Lessonia corrugata seeded spools were cultivated by spinning to increase the water motion relative to non-spinning spools, had higher growth in both the nursery and at-sea stages. Using this method, we compared the at-sea growth of sporophytes cultivated on spinning spools at different depths (1 m, 3 m, 5 m) and seasons (timing of out-planting). Finally, we compared the at-sea growth of sporophytes cultivated on spinning spools vs. non-spinning sporophytes at 3-m depth. In the nursery, sporophytes on spinning spools developed significantly faster than those on non-spinning spools: blade length was 4.6 and 2.5 cm, and holdfast area was 0.10 and 0.03 cm 2 for spinning and non-spinning spools, respectively. At-sea L. corrugata in spring had significantly greater biomass production at 3 m and 5 m (3.0 kg m −1 and 2.4 kg m −1 , respectively) and up to 96% survival. In summer, 100% of deployed kelps died at all depths. Growth was faster at 5 m (0.3 ± 0.06 kg m −1 ) in autumn and at 3 and 5 m (1.1 ± 0.1 kg m −1 and 0.8 ± 0.1 kg m −1 , respectively) in winter. At sea, sporophytes from the spinning spools grew significantly 60% larger, and survival was ~ 3 times greater over 3 months than sporophytes from non-spinning. Overall, this study shows that spinning seeded spools in the nursery improves the growth at sea, spring is the best season for out-planting L. corrugata , and 3 or 5 m depth is best for production.
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.SCITOTENV.2022.156230
Abstract: Marine eutrophication is a pervasive and growing threat to global sustainability. Macroalgal cultivation is a promising circular economy solution to achieve nutrient reduction and food security. However, the location of production hotspots is not well known. In this paper the production potential of macroalgae of high commercial value was predicted across the Baltic Sea region. In addition, the nutrient limitation within and adjacent to macroalgal farms was investigated to suggest optimal site-specific configuration of farms. The production potential of Saccharina latissima was largely driven by salinity and the highest production yields are expected in the westernmost Baltic Sea areas where salinity is >23. The direct and interactive effects of light availability, temperature, salinity and nutrient concentrations regulated the predicted changes in the production of Ulva intestinalis and Fucus vesiculosus. The western and southern Baltic Sea exhibited the highest farming potential for these species, with promising areas also in the eastern Baltic Sea. Macroalgal farming did not induce significant nutrient limitation. The expected spatial propagation of nutrient limitation caused by macroalgal farming was less than 100-250 m. Higher propagation distances were found in areas of low nutrient and low water exchange (e.g. offshore areas in the Baltic Proper) and smaller distances in areas of high nutrient and high water exchange (e.g. western Baltic Sea and Gulf of Riga). The generated maps provide the most sought-after input to support blue growth initiatives that foster the sustainable development of macroalgal cultivation and reduction of in situ nutrient loads in the Baltic Sea.
Publisher: Elsevier BV
Date: 04-2012
DOI: 10.1016/J.HUMOV.2011.08.007
Abstract: The incidence of (a)symptomatic rotator cuff tears is high, but etiologic mechanisms are unclear and treatment outcomes vary. A practical tool providing objective outcome measures and insight into etiology and potential patient subgroups is desirable. Symptomatic cuff tears coincide with humerus cranialization. Adductor co-activation during active arm abduction has been reported to reduce subacromial narrowing and pain in cuff patients. We present an easy-to-use method to evaluate adductor co-activation. Twenty healthy controls and twenty full-thickness cuff tear patients exerted EMG-recorded isometric arm abduction and adduction tasks. Ab- and adductor EMG's were expressed using the "Activation Ratio (AR)" (-1 ≤ AR ≤ 1), where lower values express more co-activation. Mean control AR's ranged from .7 to .9 with moderate to good test-retest reliability (ICC: .60-.74). Patients showed significantly more adductor co-activation during abduction, with adductor AR's ranging between .3 (teres major) and .5 (latissimus dorsi). In conclusion, the introduced method discriminates symptomatic cuff tear patients from healthy controls, quantifies adductor co-activation in an interpretable measure, and provides the opportunity to study correlations between muscle activation and humerus cranialization in a straightforward manner. It has potential as an objective outcome measure, for distinguishing symptomatic from asymptomatic cuff tears and as a tool for surgical or therapeutic decision-making.
Publisher: Springer Science and Business Media LLC
Date: 09-2022
DOI: 10.1007/S10811-022-02822-Y
Abstract: The bio ersity benefits of kelp aquaculture and afforestation are increasingly acclaimed as the industry continues to grow and develop globally, however, whether farmed kelp can provide this ecosystem service remains unclear. Using peer-reviewed literature, we evaluated whether kelp farms provide bio ersity benefits, and identified only 23 studies that discussed the effects of kelp aquaculture on bio ersity, half of which were broad reviews that only assessed the concept of ‘bio ersity’ peripherally (e.g. did not focus on specific responses or taxa). There is also a general lack of experimental research on the topic. Based on the evidence, it seems that kelp farms can create habitat via changes to the local environment, particularly through the provision of structure and changed nutrient cycling. While this can lead to increased abundance and ersity among certain taxa (e.g. fouling organisms), it seems that kelp farms typically create novel habitats that support distinct communities not equivalent to natural kelp forests. Moreover, the potential for kelp farms to support bio ersity depends on a range of operational factors, many of which may be at odds with farming objectives that require the harvest and removal of the habitat that farms provide. While more work needs to be done to address the complexity of comparisons between kelp farms and forests, especially at appropriate experimental scales, it currently seems unlikely that kelp farms will act as kelp forests and deliver meaningful bio ersity outcomes. We should instead recognise farms for providing their own valuable services and support restoration and conservation practices of kelp forests to pursue bio ersity outcomes.
Publisher: Wiley
Date: 22-01-2023
DOI: 10.1111/RAQ.12788
Abstract: Global seaweed aquaculture production has more than tripled since 2002 and is dominated by Asian countries with farming operations that typically occur in relatively wave‐protected, nearshore areas. To meet future demand, production must move to “non‐traditional” regions and into less contested waters offshore. However, the technological complexities and uncertainties in the performance of seaweed cultivated in high‐energy offshore environments are substantial and must be overcome. Here, we identify knowledge gaps and suggest a research roadmap to inform the advancement of a commercial offshore seaweed aquaculture industry using southern Australian species as case studies: (1) Durvillaea spp. (order Fucales) (2) four kelps (order Laminariales) and (3) the rhodophyte Asparagopsis . These groups lie along a spectrum of commercial viability and readiness for offshore aquaculture, and key knowledge gaps are cultivation technology and the suitability to offshore conditions. Cultivation of Durvillaea is restricted by a low level of biological and technical understanding, but there is high market potential and readiness. For laminarian kelps, commercial production in nearshore conditions is already occurring elsewhere, which make them the most likely candidate for offshore cultivation in the medium term. Asparagopsis is least suited to offshore conditions, with substantial gaps in general cultivation knowledge, and its cultivation is likely to be restricted to land‐based systems or relatively sheltered nearshore waters. The knowledge gaps identified here will inform research and development programs to advance offshore seaweed aquaculture in southern Australia and globally.
Publisher: Springer Science and Business Media LLC
Date: 15-04-2023
DOI: 10.1007/S10811-023-02968-3
Abstract: Lessonia (order Laminariales) is a kelp genus restricted to the temperate southern hemisphere, where species form dense forests from the low intertidal to 25 m depth at wave exposed sites. Lessonia spp. are among the most harvested kelps globally due to their importance in providing raw materials for food, cosmetics, bioactive and biomedical industries. Over-harvesting of natural beds can negatively affect Lessonia populations and the many species that depend on these habitats, including commercially important fish and molluscs, but good harvest management plans reduce these impacts on natural Lessonia stocks. However, the increasing demand for raw materials will likely only be met by aquaculture for which Lessonia shows high potential in pilot scale studies undertaken in Chile, New Zealand, and Australia. In this concise review, we highlight the current knowledge of Lessonia spp. taxonomy and distribution, life history, ecology and ecosystem services, wild harvest, aquaculture, and commercial applications. We discuss future research directions.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Walter de Gruyter GmbH
Date: 25-01-2023
Abstract: Tasmania is an island state in south-eastern Australia that has a long and rich history of seaweed use, research, and development. It is a cool-temperate system with 750 macroalgal species currently described. Tasmanian Aboriginal peoples have lived on this land for at least 40,000 years utilising seaweed as food, shelter, water carriers and medicine, as well as for ceremonial reasons. Modern taxonomic investigations began with French naturalist Jacques-Julien Houtou de La Billardière in 1791, and there are 184 type specimens of seaweeds originating from Tasmania. Ecological and physiological studies of seaweed in Tasmania have focussed on the dominant large brown seaweeds (Laminariales and Fucales) and have contributed significantly to the global understanding of these systems, particularly related to community resilience, seaweed-urchin interactions, their habitat-forming role for other species, responses to global change, and restoration of lost habitat. Ocean warming and changing oceanography have caused a 95% decline in surface canopy cover of Macrocystis pyrifera in eastern Tasmania since the 1950s and led to a focus on restoring these lost forests. Tasmanian seaweed communities have a uniquely high proportion (up to ∼90%) of seaweeds that rely solely on CO 2 for photosynthesis, which has implications for responses to ocean acidification. Tasmania has industries that use brown seaweeds for fucoidan extraction and beach-cast harvest for alginates, fertilisers, and feeds for agriculture. New aquaculture initiatives include integrated multi-trophic aquaculture, offshore kelp mariculture and Asparagopsis cultivation for bioactive products to reduce methane emissions in ruminants, as and the development of unexploited species including Caulerpa spp. for food.
Publisher: Mary Ann Liebert Inc
Date: 10-2019
Publisher: Oxford University Press (OUP)
Date: 04-09-2023
DOI: 10.1093/AOB/MCAD132
Publisher: Springer Science and Business Media LLC
Date: 20-07-2020
DOI: 10.1007/S10811-020-02201-5
Abstract: Seaweed aquaculture is receiving increasing attention for food and non-food applications in Europe, where it is still an emerging industry. The cultivation of seaweeds in the sea is attractive as it does not compete with agricultural crops for land and freshwater, whilst generating high yearly biomass yield. The selection of suitable cultivation sites in coastal waters is essential for the sustainable establishment and further development of seaweed aquaculture in Europe. Here, we investigate the effects of wave exposure and geographic location on growth and biofouling of kelp ( Saccharina latissima ), using a transplantation experiment along the Swedish west coast. Biofouling of kelp decreased with increased wave exposure, from 10 and 6% coverage at sheltered and moderately exposed locations, respectively, to 3% at exposed locations. Growth, measured as blade surface area, generally increased with decreased wave exposure, with approximately 40% less growth at exposed locations compared to sheltered or moderately exposed location. We identified that there is large spatial variation in growth and fouling of the seaweed biomass at the selected farm sites, with significant differences from the km-scale to the m-scale. In addition, exposure level affected the tissue composition, with a high carbon, but low nitrogen and water content at exposed locations compared to moderate and sheltered sites. Isotope signatures (i.e. δ 13 C and δ 15 N) also differed between exposure levels. Together, these results indicate that wave exposure is an important factor to consider in site selection for both yield as well as quality of the seaweed biomass for future kelp farms.
Publisher: Walter de Gruyter GmbH
Date: 24-10-2022
Abstract: Kelp aquaculture is an emerging industry outside of Asia. To be successful, this industry requires a reliable production of seedstock, the optimisation of which greatly benefits from a detailed physiological understanding of the microscopic life-cycle stages of the cultured species. This study investigated the impact of six zoospore densities (10–278 mm −2 ) on the subsequent development of Ecklonia radiata gametophytes and sporophytes. The results showed that germination rates and sex ratio were unaffected by initial zoospore density, but there were significant effects on gametophyte size and sporophyte production. After two weeks, female gametophytes were largest at an initial zoospore density of 40 mm −2 while male gametophytes grew largest at densities below 40 mm −2 , but after four weeks gametophyte size showed a negative relationship with initial zoospore density. Significantly more sporophytes developed at initial zoospore densities below 40 in iduals mm −2 and no sporophytes were observed at the highest density (271 zoospores mm −2 ). These results clearly show the importance of initial zoospore density in optimising the nursery stage of kelp aquaculture.
Publisher: Springer Science and Business Media LLC
Date: 08-11-2022
DOI: 10.1007/S10811-022-02860-6
Abstract: The cultivation of kelp typically involves two stages, where an indoor hatchery phase preceedes the grow-out phase at-sea. The in situ adhesion of microscopic propagules onto specifically designed substrates using binders has been proposed as an alternative to conventional hatchery methods where juvenile seaweeds are cultured on seeded twine, aimed at saving resources while increasing productivity as it obviates the hatchery phase. Here we tested how well kelp ( Saccharina latissima ) gametophytes adhere to cultivation ropes using two binder types (agar and κ-carrageenan) and application treatment (separate or mixed application) under two ecologically relevant flow regimes (5 and 15 cm s −1 ), and a control condition (0 cm s −1 ) in a laboratory flume. Our findings indicate that the effectiveness of a binder to retain S. latissima gametophytes onto cultivation rope, measured by the sporophyte density, was comparable for all binder types in the high flow velocity (15 cm s −1 ) treatments, including the non-binder control treatment. Sporophyte densities were highest in the low flow velocities (0 and 5 cm s −1 ) in the absence of a binder compared to all other treatment combinations. In conclusion, our results highlight that the effectiveness of binder assisted seeding of kelp propagules did not differ between the binder and non-binder treatments and was unaffected by flow velocities for the binder treatments. These findings are important in the development of novel methods and further optimisation of existing binder-based methods aimed at retaining seaweed propagules onto cultivation rope.
Publisher: Elsevier BV
Date: 11-2023
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 28-10-2023
DOI: 10.1111/JPY.13406
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.MARPOLBUL.2018.05.005
Abstract: Seaweed cultivation attracts growing interest and sustainability assessments from various perspectives are needed. The paper presents a holistic qualitative assessment of ecosystem services affected by seaweed cultivation on the Swedish west coast. Results suggest that supporting, regulating and provisioning services are mainly positively or non-affected while some of the cultural services are likely negatively affected. The analysis opens for a discussion on the framing of seaweed cultivation - is it a way of supplying ecosystem services and/or a way of generating valuable biomass? Exploring these framings further in local contexts may be valuable for identifying trade-offs and designing appropriate policies and development strategies. Many of the found impacts are likely generalizable in their character across sites and scales of cultivation, but for some services, including most of the supporting services, the character of impacts is likely to be site-specific and not generalizable.
Publisher: Frontiers Media SA
Date: 29-07-2022
DOI: 10.3389/FMARS.2022.951538
Abstract: Seaweed cultivation is gaining interest world-wide for both food and non-food applications. Global seaweed aquaculture production currently exceeds 32 Mt WW per annum but is dominated (86% of total) by Asian countries. To meet future demand for seaweed products, regions beyond Asia with aquaculture production potential are being explored. The goal of this study was to assess the suitability of the native kelp Macrocystis pyrifera (Phaeophyceae, Laminariales), for aquaculture in Tasmania, south-eastern Australia. M. pyrifera was cultivated on seeded twine on loops (1 – 5 m depth) along 100-m longlines at two sites (Okeh ton Bay and Great Taylor Bay) from April-November 2020. Temporal and spatial variability in (1) yield (kg m -1 , WW), (2) biofouling (% coverage), and (3) biochemical composition (including proximate composition, fatty acids, dietary minerals, heavy metal profiling, C, N, H, S concentrations and C:N ratio, antioxidants (phenolic compounds), and pigments (Chl- a , Chl- c , fucoxanthin)) was compared amongst the two cultivation sites, at two depths (1 and 5 m) from harvests between July – November 2020. Yield (kg m -1 , WW) did not significantly change across harvest times, but was greater at a depth of 1 m compared to 5 m. Biofouling on the kelp blades increased significantly in early spring (September). The biochemical composition of the cultured biomass varied over time, between sites and with depth for most of the compounds analysed. Higher lipid, protein and ash content was reported for cultures cultivated at Okeh ton Bay compared to Great Taylor Bay and at 5 m compared to 1 m depth, and levels of these macronutrients decreased during the harvest period. The iodine content was slightly above the tolerable content for dried seaweed products in Australia and New Zealand. The combined results of yield, biofouling, and biochemical composition suggest that, for an April deployment at the sites investigated, M. pyrifera should be harvested in July-August (mid to late winter) to optimise yield and quality of the cultured kelp biomass. These findings provide a better understanding of the variation in growth and quality of cultivated M. pyrifera biomass in the region, and inform future management and development of kelp aquaculture in south-eastern Australia and in a global context.
Publisher: Elsevier BV
Date: 06-2021
No related grants have been discovered for Wouter Visch.