• Jellyfish size might influence their nut

    From ScienceDaily@1:317/3 to All on Mon Mar 20 22:30:24 2023
    Jellyfish size might influence their nutritional value
    If jellyfish are 95% water, what makes them such nutritious snacks for so
    many marine organisms?

    Date:
    March 20, 2023
    Source:
    University of British Columbia
    Summary:
    Researchers confirmed what was already known: jellyfish eat
    bigger prey as they grow, which means they also occupy a higher
    position in the food web as they grow. They also found that some
    of the concentrations of 'healthy fats,' increase as jellyfish
    grow. These changes might be influenced by their diet, and as
    they feed on bigger prey with higher levels of fatty acids, the
    jellyfish accumulate more of these fatty acids.


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    FULL STORY ========================================================================== Drifting along in ocean currents, jellyfish can be both predator and
    prey. They eat almost anything they can capture, and follow the typical
    oceanic pattern of large eats small. Now a recent University of British Columbia study on these gelatinous globs suggests jellyfish may get more nutritious as they get bigger.


    ==========================================================================
    As jellyfish grow, their size changes largely due to the chances of
    prey encounter, the length and number of tentacles, and their bells
    (the umbrella- like part of them). As a result, smaller jellyfish eat phytoplankton, microzooplankton, and eggs, while larger jellyfish can
    eat all of that plus shrimp and even fish. However, jellyfish are also
    largely preyed upon by animals in and out of the water. Jellyfish are
    important prey because they are easy to digest due to their high water
    content, and they are easy to catch.

    "Our study looked more closely to see if there was any information
    we could draw about nutrition in jellyfish," said Jessica Schaub,
    lead author and a UBC PhD student at the Institute for the Oceans and
    Fisheries and the Department of Earth, Oceans and Atmospheric Sciences.

    "This information helps us understand the true value of jellyfish
    as food. We looked at how the energy that moves through a food web
    might look as it moves through jellyfish. What they eat, what they are
    composed of, and how this might affect what eats them." In Heriot Bay,
    B.C., for example, the moon jelly may often find themselves being eaten
    by other jellyfish, fish and other invertebrates.

    Schaub, and her team, which includes associate professor Dr. Brian Hunt,
    who heads the Pelagic Ecosystem Lab at the Institute for the Oceans
    and Fisheries, took a look at how jellyfish size, diet and nutritional
    quality all mesh together. Nutritional quality can reflect an organism's
    life history -- the composition of a jellyfish can change in response
    to individual changes in diet and physiological changes.

    The team, over two one-day periods in July and September 2019, collected
    150 moon jellyfish and measured their size. After drying them, they
    measured the jellyfish for specific compositional elements.

    Schaub described what they discovered.

    "First, we confirmed what was already known: jellyfish eat bigger
    prey as they grow, which means they also occupy a higher position in
    the food web as they grow," she said. "We also found that some of the concentrations of 'healthy fats,' increase as jellyfish grow. We found
    some evidence that these changes might be influenced by their diet,
    and as they feed on bigger prey with higher levels of fatty acids, the jellyfish accumulate more of these fatty acids." "This means bigger
    jellyfish might be considered more nutritious," said Schaub.

    The study found size-trends which emphasize just how important it
    is to consider jellyfish size when we are talking about marine food
    webs. Including these creatures will not only help their representation
    in food web models, but can also inform other studies.

    Looking towards the future, Schaub described what may come next.

    "Our recommendation for future studies on jellyfish predators is to
    consider size more thoroughly. Feeding on a young, small jellyfish is
    different than feeding on a larger and older jellyfish."
    * RELATED_TOPICS
    o Plants_&_Animals
    # Sea_Life # Marine_Biology # Fisheries #
    Pests_and_Parasites
    o Earth_&_Climate
    # Ecology # Water # Environmental_Awareness # Ecosystems
    * RELATED_TERMS
    o Jellyfish o Omega-3_fatty_acid o Pitcher_plant o Snake o
    Essential_nutrient o Algal_bloom o Amino_acid o Trophic_level

    ========================================================================== Story Source: Materials provided by University_of_British_Columbia. Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Jessica Schaub, Anna K. McLaskey, Ian Forster, Brian P. V. Hunt.

    Size‐based changes in trophic ecology and nutritional quality
    of moon jellyfish ( Aurelia labiata ). Ecosphere, 2023; 14 (3)
    DOI: 10.1002/ ecs2.4430 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2023/03/230320143818.htm

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