Developing Biohybrid Robotic Jellyfish (Aurelia aurita) for Free-swimming Tests in the Laboratory and in the Field

BIO-PROTOCOL ◽  
2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Nicole Xu ◽  
James Townsend ◽  
John Costello ◽  
Sean Colin ◽  
Brad Gemmell ◽  
...  
Keyword(s):  
Aurelia Aurita ◽  
Free Swimming

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

Density-driven water exchange controls seasonal declines in jellyfish (Aurelia aurita) abundance in a shallow fjord system

2018 ◽  
Vol 597 ◽  
pp. 137-145 ◽  
Author(s):  
J Goldstein ◽  
C Jürgensen ◽  
UK Steiner ◽  
HU Riisgård
Keyword(s):  
Water Exchange ◽  
Aurelia Aurita ◽  
Fjord System

I3S Pattern as a mark-recapture tool to identify captured and free-swimming sea turtles: an assessment

2018 ◽  
Vol 589 ◽  
pp. 263-268 ◽  
Author(s):  
B Calmanovici ◽  
D Waayers ◽  
J Reisser ◽  
J Clifton ◽  
M Proietti
Keyword(s):  
Sea Turtles ◽  
Free Swimming ◽  
Mark Recapture

scholarly journals Morphological abnormality in thornback ray Raja clavata in the Irish Sea

2021 ◽  
Author(s):  
L. J. Clarke
Keyword(s):  
Irish Sea ◽  
Beam Trawl ◽  
Morphological Abnormality ◽  
Free Swimming ◽  
Pectoral Fins ◽  
North Wales ◽  
Head Section ◽  
Thornback Ray ◽  
Raja Clavata ◽  
The Irish Sea

AbstractA free-swimming thornback ray Raja clavata specimen demonstrating significant morphological abnormality is reported, captured by beam trawl in the Irish Sea off north Wales, UK. The anterior sections of both pectoral fins were separated from the head section for a length of approximately 140 mm extending from the rostrum tip to a point posterior of the spiracles, along with abnormal morphology of the gill slits. This phenomenon has been observed elsewhere but is the first documented example of this abnormality in the eastern Irish Sea, despite widespread targeting of the species across the region by commercial and recreational fishers. Possible causes and consequences of the observed abnormality are discussed.

scholarly journals Shorter, warmer winters may inhibit production of ephyrae in a population of the moon jellyfish Aurelia aurita

Hydrobiologia ◽  
2020 ◽  
Author(s):  
Alexandra Loveridge ◽  
Cathy H. Lucas ◽  
Kylie A. Pitt
Keyword(s):  
Incubation Time ◽  
Life Stage ◽  
Aurelia Aurita ◽  
The Moon ◽  
Minimum Period ◽  
Moon Jellyfish ◽  
Winter Conditions ◽  
Scyphozoan Jellyfish ◽  
Significant Production ◽  
Planula Larvae

AbstractScyphozoan jellyfish blooms display high interannual variability in terms of timing of appearance and size of the bloom. To understand the causes of this variability, the conditions experienced by the polyps prior to the production of ephyrae in the spring were examined. Polyps reared from planula larvae of Aurelia aurita medusae collected from southern England (50°49′58.8; − 1°05′36.9) were incubated under orthogonal combinations of temperature (4, 7, 10 °C) and duration (2, 4, 6, 8 weeks), representing the range of winter conditions in that region, before experiencing an increase to 13 °C. Timing and success of strobilation were recorded. No significant production of ephyrae was observed in any of the 2- and 4-week incubations, or in any 10 °C incubation. Time to first ephyra release decreased with longer winter incubations, and more ephyrae were produced following longer and colder winter simulations. This experiment indicates that A. aurita requires a minimum period of cooler temperatures to strobilate, and contradicts claims that jellyfish populations will be more prevalent in warming oceans, specifically in the context of warmer winter conditions. Such investigations on population-specific ontogeny highlights the need to examine each life stage separately as well as in the context of its environment.

scholarly journals Wireless logging of extracellular neuronal activity in the telencephalon of free-swimming salmonids

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Susumu Takahashi ◽  
Takumi Hombe ◽  
Riku Takahashi ◽  
Kaoru Ide ◽  
Shinichiro Okamoto ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Environmental Cues ◽  
Fish Movement ◽  
Water Tank ◽  
Head Direction ◽  
Free Swimming ◽  
Rodent Brain ◽  
River Migration ◽  
Spike Waveforms ◽  
The Brain

Abstract Background Salmonids return to the river where they were born in a phenomenon known as mother-river migration. The underpinning of migration has been extensively examined, particularly regarding the behavioral correlations of external environmental cues such as the scent of the mother-river and geomagnetic compass. However, neuronal underpinning remains elusive, as there have been no biologging techniques suited to monitor neuronal activity in the brain of large free-swimming fish. In this study, we developed a wireless biologging system to record extracellular neuronal activity in the brains of free-swimming salmonids. Results Using this system, we recorded multiple neuronal activities from the telencephalon of trout swimming in a rectangular water tank. As proof of principle, we examined the activity statistics for extracellular spike waveforms and timing. We found cells firing maximally in response to a specific head direction, similar to the head direction cells found in the rodent brain. The results of our study suggest that the recorded signals originate from neurons. Conclusions We anticipate that our biologging system will facilitate a more detailed investigation into the neural underpinning of fish movement using internally generated information, including responses to external cues.

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