Globally, anthropogenic sounds have become louder and more persistent, however, little is known about how invertebrates detect and respond to human-made sound. Now, new research shown noise associated with boats causes causes temporal hearing loss in squids across different stages of their life cycle.
The hummingbird bobtail squid (Euprymna berryi) has a short lifespan of at least 6 months, which make them a convenient animal for lab studies. Hearing and behavioural observations were made by researchers before, during and after 15 minutes of vessel sound playback, to test how these squids react to noise pollution, and noted that these squids decrease their hearing sensitivity after exposure to noise, and particularly noise affected juveniles. Juvenile squids experienced an important hearing loss sensitivity after noise exposure between 400 and 800 Hz, while adult and mature squids decreased their sensibility after 200 to 600 Hz exposure, showing more resistence. All squids recovered auditory sensitivity within two hours.
Researchers aim the inclusion of cephalopods within management and policy, because anthropogenic activities and associated sound levels in the ocean are increasing, while the role sound plays in cephalopod life history is only just beginning to be understood.
Photo by Pascal Girard
Reference () Putland et al. 2023. Vessel sound causes hearing loss for hummingbird bobtail squid (Euprymna berryi). Frontiers in Marine Science
Comb jellies—also known as ctenophores—come in a wide range of shapes and sizes. Many are transparent, but some deep-sea species, like the abyssal comb jelly, Beroe abyssicola, are ruby red or deep purple in color. So far, scientists have described approximately 200 ctenophore species.
Comb jellies swim by flicking hair-like ctenes back and forth. When the lights of our submersibles illuminate an abyssal comb jelly, the ctene rows diffract the light into the colors of the rainbow, creating those dazzling disco lights.
Most animals in the midnight zone produce bioluminescence. The abyssal comb jelly has a scarlet stomach that absorbs the light produced by meals digesting in its gut. The red pigment absorbs blue-green bioluminescence, keeping Beroe hidden from predators. Many other deep-sea jellies employ a similar strategy. Learn more about these dazzling denizens of the deep on our website.
Koh Samui
St. John, US Virgin Islands
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Tomopterids are marine planktonic polychaetes—commonly known as Gossamer Worms — that swim in the water column, never touching the seafloor. Growing anywhere between 1 cm and 30 cm long. They are also one of the very few marine creatures that can produce yellow light, spewing their bioluminescence to scare off predators
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