Given global concerns over the depleting resources of our seas and oceans, and the increasing lack of sustainable seafood options, jellyfish are emerging as a potential future food. Jellyfish ...currently represent a sustainable food resource, one whose availability will likely increase with global warming. While jellyfish are a popular delicacy in many parts of Asia, it is currently an unfamiliar food to the majority of Western diners. In this paper, we show how multisensory experience design can be used to introduce diners to this highly-textured, if essentially flavourless, source of food. Created by chef Jozef Youssef, and served at Kitchen Theory's Gastrophysics Chefs Table, the jellyfish dish is placed on a table that is projection mapped with an underwater scene, accompanied by a bespoke, crossmodally-congruent soundscape delivered to diners wearing headphones. The response from diners to this unusual food has so far been uniformly positive.
To investigate whether dinoflagellates and diatoms interact with the polyp stage of
Aurelia
sp., feeding responses to dinoflagellates and diatoms and the survival of polyps fed on phytoplankton or
...Artemia
sp. were studied in laboratory experiments. Feeding responses to motionless diatoms, defined by the movement of the polyp tentacles, were seldom seen but responses to motile dinoflagellates were clearly observed. Meanwhile, the feeding response was significantly positively related to the equivalent spherical diameters of the dinoflagellates. Gastric cavity analysis indicated that micro-phytoplankton (
Alexandrium
catenella, Akashiwo sanguinea),
which were in high concentration, could be detected, but nano-phytoplankton (
Prorocentrum donghaiense
,
Karenia brevis
) were not detected, implying that nano-phytoplankton were not eaten by
Aurelia
sp. polyps. We also observed that dinoflagellates whether nano or micro lost their motility and became attached on
Aurelia
sp. polyps. Compared to feeding on
Artemia
sp. nauplii, survival of the polyps was significantly depressed after 91 days feeding on phytoplankton in all combinations of species and concentrations. High mortality of the polyps when feeding on a high concentration (80 mg C l
−1
) of dinoflagellates implied that the polyps may be harmed when they coexisted with dinoflagellate blooms, so that the mass occurrence of large numbers of
Aurelia
medusae in natural coastal waters was depressed.
This study evaluates the size-dependent predation of fish larvae by jellyfish, exemplified with flounder
Paralichthys olivaceus
and moon jellyfish
Aurelia aurita
under laboratory conditions. The ...effects of some environmental factors on the size-dependent predation were also investigated. The results indicate that the predation rate increased with larval development, until the larvae had developed the ability to actively avoid predation at approximately 11-day post-hatching and decreased thereafter. This suggests a size-dependent predation on the fish larvae. Water temperature and predator size significantly affected the predation rate of the medusae on the fish larvae, but the temperature and size effects were markedly reduced as the larvae reached post-larval stage. These findings suggest that water temperature and jellyfish size interacted with the ontogenetic development of the fish larvae to affect the predation rates. The presence of alternative prey
Artemia salina
, could alleviate the predation rate on the fish larvae, whereas light conditions showed no effects on the predation rate. Due to their overlaps in spatial and temporal distributions along the north Chinese coast, jellyfish are likely to prey upon flounder larvae and thus affect the recruitment of the wild fish populations.
Mansor, K.N.A.A.K.; Roseli, N.H.; Ali, F.S.M., and Akhir, M.F.M., 2023. Physical properties of seawater in Malacca Strait (Southeast Asia) during monsoon seasons. Journal of Coastal Research, 39(5), ...921–932. Charlotte (North Carolina), ISSN 0749-0208. Malacca Strait (MS) is a narrow passage in Southeast Asia mainly influenced by the Asian monsoon system. As a busy international maritime route, MS is highly exposed to seawater pollution, harmful algal blooms, and jellyfish blooms. To understand the physical properties of the water column in MS, scientific cruise data were used to examine mixed layer depth, stratification frequency, and water mass distribution during two monsoon seasons (March and August). Results showed that surface water in March is fresher and warmer than in August, whereas the bottom depth in March is more saline and cooler than in August. The mixed layer depth for both months did not exceed approximately 15 m for temperature and salinity, with thermocline and halocline layers observed below the mixed layer depth. The temperature and salinity diagram classified three water masses from the cruise dataset—surface warm water, mixed water, and subsurface water—with the potential density anomaly ranging between about 15.5 and 24 kg/m3. The highest density of water mass, subsurface water, was found only in March at a depth between 54 and 80 m. This cool, high-salinity water is the remaining NE monsoon water mass that settled near the bottom because March is the period of change from NE monsoon to SW monsoon. During this time, winds weaken and solar radiation increases, thus creating stable warm surface water. Strong stratification observed in March prevented mixing between warm surface water and cool bottom water. Meanwhile, August is characterized by a warm SW monsoon; thus, the whole MS is occupied by warmer water. This research presents the variation of physical properties in the water column and reveals the influences of monsoon season on shifts of stratification and water mass distribution.
We address the problem of jellyfish polyp counting in underwater images. Modern methods utilize convolutional neural networks for feature extraction and work in two stages. First, hypothetical ...regions are proposed at potential locations, the features of the regions are extracted and classified according to the contained object. Such methods typically require a dense grid for region proposals, explicitly test various scales and are prone to failure in densely populated regions. We propose a segmentation-based polyp counter — SegCo. A convolutional neural network is trained to produce locally-circular segmentation masks on the polyps, which are then detected by localizing circularly symmetric areas in the segmented image. Detection stage is efficient and avoids a greedy search over position and scales. SegCo outperforms the current state-of-the-art object detector RetinaNet (Lin et al., 2017) and the recent specialized polyp detection method PoCo (Vodopivec et al., 2018) by 2% and 24% in F-score, respectively, and sets a new state-of-the-art in polyp detection.
In the course of a survey of a specimen of the jellyfish Pelagia noctiluca (collected at Villefranche-sur-Mer, France) using scanning electron microscopy, the suctorian ciliate Trichophrya salparum ...was found on the jellyfish exumbrella. This ciliate species is reported for the first time on a scyphozoan jellyfish host. A redescription of this suctorian species is presented together with data on its distribution and host prevalence.
Control of vortex rings for manoeuvrability Gemmell, Brad J.; Troolin, Daniel R.; Costello, John H. ...
Journal of the Royal Society interface,
07/2015, Letnik:
12, Številka:
108
Journal Article
Recenzirano
Odprti dostop
Manoeuvrability is critical to the success of many species. Selective forces acting over millions of years have resulted in a range of capabilities currently unmatched by machines. Thus, ...understanding animal control of fluids for manoeuvring has both biological and engineering applications. Within inertial fluid regimes, propulsion involves the formation and interaction of vortices to generate thrust. We use both volumetric and planar imaging techniques to quantify how jellyfish (Aurelia aurita) modulate vortex rings during turning behaviour. Our results show that these animals distort individual vortex rings during turns to alter the force balance across the animal, primarily through kinematic modulation of the bell margin. We find that only a portion of the vortex ring separates from the body during turns, which may increase torque. Using a fluorescent actin staining method, we demonstrate the presence of radial muscle fibres lining the bell along the margin. The presence of radial muscles provides a mechanistic explanation for the ability of scyphomedusae to alter their bell kinematics to generate non-symmetric thrust for manoeuvring. These results illustrate the advantage of combining imaging methods and provide new insights into the modulation and control of vorticity for low-speed animal manoeuvring.
The inclusion of distributed generation (DG) units in the distribution network (DN) effectively cuts down the power losses (PL) and strengthens the voltage profile (VP). This paper examines the ...effect of allocating different distributed generation (DG) in radial distribution networks (RDN) through an implementation of an optimization technique using a recently introduced bio- inspired algorithm known as a jellyfish search optimizer (JSO). Unlike the other optimization algorithms, the JSO algorithm evades the local optimal trap and reaches the optimal solution in less time. The DG position(s) and size(s) are optimized for active power loss (APL) minimization with respect to several constraints. The effectiveness and robustness of the proposed optimization technique using JSO algorithm is investigated on a balanced IEEE RDNs with 33, 69 and 118-buses. The simulation outcomes are obtained for different types (type I, II and III) of DG placement. Additionally, a comprehensive comparative study has been performed for the JSO and other algorithms. The comparison exemplifies that the proposed JSO optimization approach produces a better optimal solution with steady convergence than other techniques reported in the literature. Also, the simulation findings show the potentiality of JSO optimization method for solving complex optimization problems.
Modifications to estuaries through the construction of barrages alter the natural dynamics of inhabitant species by controlling freshwater inputs into those systems. To understand the effects of ...modified freshwater flows on a native scyphozoan jellyfish, Catostylus mosaicus, and to identify the environmental drivers of medusa occurrence, we analysed a 20-year observational dataset composed of 11 environmental variables and medusa presence/absence from 15 sampling stations located below the Fitzroy Barrage, in the Fitzroy River, Queensland. Major decreases in salinity (minimum salinity 0) occurred approximately 16 times during the 20-year period and medusae disappeared from the estuary following every major freshwater flow event. Salinity was identified as the most influential variable contributing to variation in the number of upper estuary sites reporting jellyfish. We then ran two laboratory experiments to test the following hypotheses: (i) prolonged decreases in salinity impair survival, pulsation, and respiration rates of C. mosaicus medusae; and (ii) transient decreases temporarily impair pulsation and respiration but medusae recover when salinity returns to normal levels. Medusae were unable to survive extended periods at extreme low salinities, such that they would experience when a barrage opens fully, but had significantly higher survival and recovery rates following smaller, transient changes to salinity that might occur following a moderate rainfall event. This demonstrates for the first time that modification of freshwater flow by a barrage regulates the population dynamics of an estuarine jellyfish, and highlights the need for robust, long term datasets, and to firmly embed experimental approaches in realistic ecological contexts.
•Changes to freshwater flow by a barrage regulates the population dynamics of estuarine jellyfish.•Adult medusae cannot survive extended periods at extreme low salinities.•Adult medusae can survive and recover from short-term freshwater inputs.
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