In the wind farm, four oyster tables have been placed at the base of some wind turbines. Over time, these oyster tables have become overgrown with a variety of animals. Animals were sampled from the oyster tables during monitoring missions in July 2021 and August 2023 by scraping off some vegetation. These samples were examined by Eurofins AquaSense. The study revealed the presence of a specimen of the orange pistol shrimp (Alpheus macrocheles) in the sample from one of the oyster tables in 2023. This species has not previously been found in Dutch waters and is the first “true” pistol shrimp for our country.
Orange pistol shrimp (Alpheus macrocheles)
The species can reach 3.5 cm in length and, as the name suggests, is orange-colored, with no specific pattern. There are more than 600 species of pistol shrimp (Alpheidae) in the world, which are also called bang shrimp. They are named for the loud pops that the vast majority of these species can produce using their special claws. The poppers are said to reach up to a kilometer away and in several species have a function in prey capture, defense, drilling into rock or soft bottoms and sending signals. Another characteristic of pistol shrimp is that the eyes are partially or completely covered in front of the leading edge of the dorsal shield. This provides some protection from the bangs.
Climate change and offshore wind farms
Given the amount of hard substrate in the Borssele wind farm and the extremely small area from which samples were scraped, it is likely that a population of the orange pistol shrimp lives in the wind farm. Presumably they settled in the wind farm after the larvae moved with the sea currents. The recent expansion of the orange pistol shrimp to the northeast and North Sea fits the pattern of several crustaceans with larvae floating in the water column showing such a change in their distribution range. One possible explanation for this trend is that it is a result of climate change. The construction of offshore wind farms, and the associated foundations and stone dumping at the base of the turbines, is also contributing to an increase in suitable habitat for this particular species.
Only one previous sighting
The Orange pistol shrimp has only been sighted once before throughout the North Sea, in English territory, off the mouth of the Thames in 2007. There is also a sighting just west of the Strait of Dover in 2014. More common is the orange pistol shrimp in the western and central Channel.
A more detailed article on this find appeared in early June in The Seahorse, the periodical of the Strandwerk community.
Photography: Marco Faasse