'Trojan fish': Invasive rabbitfish spread invasive species

Date: May 17, 2017

Source: Helmholtz Centre for Ocean Research Kiel (GEOMAR)

The mystery of how some invasive species may rapidly invade and spread in the world's oceans without assistance by marine traffic may have been partly solved by a new Mediterranean Sea study. Red Sea rabbitfish invaded the Mediterranean through the Suez Canal in the 20th century. Soon after, more than 60 species of small Red Sea marine animals, known as foraminifera, also invaded the Mediterranean.

New research, lead by Tamar Guy-Haim of the Israel Oceanographic and Limnological Research (IOLR) / the GEOMAR Helmholtz Centre for Ocean Research Kiel released in Limnology and Oceanography Letters this week, reveals that the rabbitfish brought the other marine life with them. The research was done in collaboration with Orit Hyams-Kaphzan (Geological Survey of Israel, GSI), Erez Yeruham (IOLR), Ahuva Almogi-Labin (GSI), and James Carlton (Williams College -- Mystic Seaport, USA).

Although plant-eaters, the rabbitfish accidentally scoop up marine animals from the sea floor while feeding. After feeding and swimming long distances, the fish defecate the live animals that had survived the trip through the fish's digestive system. Fish moving plants and animals ? called "ichthyochory," or dispersal of species by fish ? has been known in lakes and rivers but hardly from the marine environment.

The new study is the first to document fish dispersal as a means of long-distance dispersal of alien species in the ocean. The researchers studied fresh waste from the fish. They found live forams as well as other live marine animals, such as snails, clams, and worms. Museum specimens confirmed that rabbitfish have been eating and moving species for decades.

Continued