Bioprospecting for Jellyceuticals: Evaluating jellyfish as a sustainable biomedical resource
Ford, Dewi
Ford, Dewi
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2024-06
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Abstract
Interest in using the class Scyphozoa (‘jellyfish’) as bioresources is on the rise, though it remains unclear how the stability of jellyfish populations will be affected by increased fishery demands. While aquaculture is seldom considered as an option for obtaining jellyfish biomass, it may be necessary to relieve natural populations from fishing pressures and conserve ecosystem services supported by jellyfish. It is therefore important to assess whether aquaculture could provide sought-after jellyfish bioresources. Conversely, there is evidence to suggest that jellyfish abundances might be increasing globally, and it has been suggested that jellyfish fisheries may help regulate disaster events associated with jellyfish population ‘blooms’. Understanding how environmental variables regulate jellyfish physiology is essential to better predict how their population dynamics may change in the future. This type of assessment could help determine whether aquaculture or fisheries will represent a more sustainable method of jellyfish exploitation in the future.
This thesis investigated key environmental drivers of jellyfish development throughout multiple life stages to improve aquaculture techniques and infer how different natural environmental conditions might influence jellyfish physiology. Chapter 2 used a meta-analytical approach to examine the types of research that have been conducted on every scyphozoan genus between 2001-2021. This chapter identified understudied areas of jellyfish biology that could constrain our capacity to harvest jellyfish biomass sustainably. Notably, it was highlighted that relatively few studies have focused on the general biology of jellyfish early life stages or the ecophysiology of the medusa life stage. Chapter 3 assessed the influence of seawater media on Aurelia aurita (moon jellyfish) planula larva and polyp development. Cultivating A. aurita planulae and polyps in artificial seawater reduced the likelihood of successful metamorphosis compared to when natural seawater was used, but husbandry methods that can be used to overcome this issue and cultivate jellyfish with limited access to natural seawater were described. Chapter 4 considered how temperature and feeding regimes influence the growth and asexual reproduction of A. aurita polyps. Temperature and food availability had different effects on somatic growth and populations cultivated in warmer conditions produced more ephyrae (juvenile jellyfish) following a controlled winter simulation.
Chapter 5 tested the influence of similar temperature regimes on subsequent ephyra growth and development into adult medusae. The fastest somatic growth rates were observed at 15 °C and sexual reproduction was impaired at temperatures > 18 °C. Chapter 6 extracted and characterised collagenous solutions derived from medusa samples cultivated within a laboratory setting. The results suggested that the thermal stability of jellyfish collagen is regulated by specific environmental factors and could be optimised through different cultivation protocols. In Chapter 7, ephyrae from the tropical genus Cassiopea (upside-down jellyfish) were cultivated at different temperatures and a range of developmental, morphological, and behavioural metrics were investigated. Somatic growth and morphological development were impaired at temperatures > 25 °C, indicating the stability of Cassiopea sp. fisheries within tropical regions could decline as ocean temperatures rise. Morphometric results from this chapter also suggested that Cassiopea sp. display morphological plasticity in response to temperature. Collectively, these chapters provide insights into how certain environmental conditions can regulate jellyfish biomass production and growth, how jellyfish-derived collagen can be obtained ex situ, and where further research is needed to ensure a sustainable growth of jellyfish exploitation.
Citation
Ford, D. (2024). Bioprospecting for Jellyceuticals: Evaluating jellyfish as a sustainable biomedical resource [Unpublished doctoral thesis]. University of Chester.
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University of Chester
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Thesis or dissertation
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en