Crustaceans

DAN Encourages Safe Diving During Florida Lobster Mini Season

While it’s a fun, challenging and tasty experience for most, more than 20 divers have lost their lives during mini season in the last decade.

Through analysis of these tragic deaths, researchers at Divers Alert Network (DAN) have identified the most relevant contributing factors and most important safety practices for divers participating in the annual event.

These tips probably won’t surprise you, but sometimes the most basic precautions are the most likely to save a life.

The two hermit crab species (Coenobita rugosus on the top left and C. perlatus on the top right), with the four shell types used in the research

Why two hermit crab species on same beach don't fight over shells

Researchers from the University of Bayreuth, Germany discovered how two hermit crab species co-exist on the same beach without fighting over limited resources like food or shelter.

The maze that the crabs in the study had to get through.

Study reveals crabs' spatial learning skills

Many studies about spatial learning in animals have focused on land animals, and less so in marine animals, possibly due to the difficulty in following them around.

This new study, led by Swansea University marine biologist Ed Pope and master’s student Ross Davies, gives a glimpse into the European shore crab’s level of spatial learning ability.

First, the team constructed a special maze that measured 75cm by 50cm. A single crushed mussel was placed at the end of it.

Some rockpool prawns prefer to stick with the food they found while others tend to forage for more choices.

Shy prawns fare better than bolder ones

Scientists at the University of Exeter studying rockpool prawns (Palaemon elegant) have discovered that they exhibit different personalities, and those that are "shy" tend to fare better when competing for food.

The findings of their study was published in Volume 140 of the journal Animal Behaviour.

In the study, the prawns, all taken from the Gyllyngvase beach in Falmouth, were tagged and tested on their level of boldness by placing them in an unfamiliar tank and observing how much they explored and ventured to the centre.

Deep sea crabs are sensible to blue and ultraviolet light
Deep sea crabs are sensible to blue and ultraviolet light

Deep sea crabs see in colour

Investigating deep waters off Bahamas, US-based researchers recorded the glow of tiny bioluminescent species using a submersible vehicle.

Descending to sites between 600 and 1000m down, the scientists observed flashes of bioluminescence where plankton collided with boulders and corals.

The team also studied how crustaceans react to this light, and found previously unknown sensitivities to blue and ultra violet wavelengths.