Ultrasounds for endangered abalone mollusks
Ultrasounds proven an effective, hands-off way to help spawn endangered abalone

Date:
February 25, 2022
Source:
University of California - Davis
Summary:
The world's abalone are threatened, endangered or otherwise
vulnerable in nearly every corner of the planet. If only we could
wave a magic wand to know when abalone are ready to reproduce,
without even touching them.

Scientists have now found that wand -- although it isn't magic,
and it only looks like a wand. It's an ultrasound transducer, and
it can be used to quickly and noninvasively detect when abalone
are ready to spawn, they report in a study this week.



FULL STORY ==========================================================================
The world's abalone are threatened, endangered or otherwise vulnerable
in nearly every corner of the planet. While captive breeding efforts
are underway for some species, these giant sea snails are notoriously
difficult to spawn. If only we could wave a magic wand to know when
abalone are ready to reproduce, without even touching them.


========================================================================== Scientists from the University of California, Davis, found that wand
- - although it isn't magic, and it only looks like a wand. It's an
ultrasound transducer, and it can be used to quickly and noninvasively
detect when abalone are ready to spawn, according to a study published
in the journalFrontiers in Marine Science.

The technique is expected to help abalone farmers and captive breeding
managers produce more abalone, with minimal stress to the animal.

Increasing abalone welfare Abalone suction onto surfaces and typically
have to be pried off for gonad inspection before spawning. For these
animals -- particularly endangered abalone -- the less they are handled,
the less opportunity for stress or physical harm.

"There are not a lot of animal welfare methods applied to invertebrate
animals, let alone for aquatic species," said corresponding author Jackson Gross, an assistant professor of Cooperative Extension in Aquaculture with
the UC Davis Department of Animal Science. "Here's a way to increase
the welfare of an abalone without bringing added stress to them."
The United States Navy's Pacific Fleet funded the research as part of its efforts to conserve federally endangered black abalone and find better
ways to assess their reproductive health. Because of black abalones'
low numbers and high vulnerability, the authors used closely related
farmed red abalone to test the effectiveness of ultrasounds on abalone.



========================================================================== Gross had used the technique for gonad assessments on sturgeon
and catfish, but it had never been tested for sea snails until this
study. When Gross saw a video of a veterinarian in Scotland conducting
an ultrasound on a large land snail, he felt certain it would work
for abalone.

Testing the tech With Gross' background, the extensive knowledge of the
white abalone captive breeding program at the UC Davis Bodega Marine Laboratory, and first author Sara Boles' experience studying red abalone,
the authors tested the method on 12 farm-raised red abalone and about 100
red abalone raised at Bodega Marine Lab. They monitored the lab-raised
abalone for seven weeks to detect seasonal changes in their gonad size.

They found that ultrasounds could differentiate reproductive tissues
from digestive tissues. They were then able to create a gonad index
score ranging from 1 to 5 that indicates the abalones' readiness
to reproduce. Abalone measuring in the 3 to 5 range could be ideal
candidates for spawning. They also found the technology was sensitive
enough to detect changes both before and after spawning.

"This is very helpful for broodstock managers when trying to select
individuals for a spawning season, whether for production aquaculture or conservation," said Boles, a postdoctoral researcher with the UC Davis
Coastal and Marine Sciences Institute at the Bodega Marine Laboratory.



==========================================================================
How to give abalone an ultrasound So how do you ultrasound an
abalone? It's fairly straightforward.

You submerge the abalone underwater in its tank and place the ultrasound transducer on the outside of the tank by the abalone's foot. The sound
passes through the tank and transmits the image.

Routine assessments using ultrasounds can be conducted without touching
the animal at all. Abalone do still have to be handled for spawning
events, but ultrasounds can minimize the handling involved.

Abalone are an ecologically and culturally important keystone species for California's coastal ecosystem. They face multiple, often intertwining
threats -- from warming ocean temperatures and disease to crashing kelp
forests and habitat degradation.

"We're excited to see how much faster we can use this technology to
assess the health of these animals, especially in a world where climate
change is making an impact," Gross said.

The study's co-authors include Isabelle Neylan and Laura Rogers-Bennett
of UC Davis.

========================================================================== Story Source: Materials provided by
University_of_California_-_Davis. Original written by Kat Kerlin. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Sara E. Boles, Isabelle P. Neylan, Laura Rogers-Bennett, Jackson A.

Gross. Evaluation of Gonad Reproductive Condition Using Non-invasive
Ultrasonography in Red Abalone (Haliotis rufescens). Frontiers in
Marine Science, 2022; 9 DOI: 10.3389/fmars.2022.784481 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220225142118.htm

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