Wildlife

Crab Congress

Untold numbers of giant spider crabs have amassed in the waters near Australia’s second-largest city of Melbourne in a gathering some experts believe is associated with moulting.

The hundreds of thousands of crustaceans that have congregated in Port Phillip Bay could be there for “safety in numbers” as they shed their hard outer shells in order to grow. They are more vulnerable to such predators as cormorants and stingrays during moult.

While the gathering probably happens each year, it was virtually unknown to local communities until underwater photographer Sheree Marris released a video that documented the phenomenon.

Polluting the Deep

High levels of man-made persistent organic pollutants have been found in tiny creatures collected in the world’s deepest ocean trenches.

Shrimplike crustaceans, called amphipods, captured in the Marianas Trench and the Kermadec Trench were found contaminated with PCBs, once used in plastics manufacturing, and PBDEs, which are the main ingredients in flame retardants.

The levels of PCBs in the Marianas Trench amphipods were higher than in the estuaries of China’s most polluted rivers, researcher Alan Jamieson told Nature.