The Indo-Pacific damselfish Neopomacentrus cyanomos at Trinidad, southeast Caribbean

The Indo-West Pacific (IWP) damselfish Neopomacentrus cyanomos was first found in the Atlantic Ocean in 2013, on reefs in Mexico in the southwest Gulf of Mexico (GoMx). By 2018 it was known throughout most of the GoMx, but nowhere else in the Atlantic. Evidence indicates it was introduced to the GoMx by offshore petroleum infrastructure moved in water from its native range, rather than by aquarium-release or commercial shipping. There are three tropical Atlantic areas with offshore petroleum fields in addition to the GoMx: (i) at Trinidad (southeast Caribbean), (ii) at central Brazil, and (iii) at west Africa. Offshore infrastructure moves between those oilfields, and between them and support facilities in the IWP. If N. cyanomos was brought to the Atlantic by such infrastructure relocation, then it could also be at other Atlantic oilfields. To assess that possibility, we surveyed suitable habitat at Trinidad (mid 2019), and nearby Tobago (early 2020). We found N. cyanomos at all sites surveyed at Trinidad, but none at Tobago. At Trinidad this species was common on shallow reefs fringing an aquatic “parking lot” for mobile petroleum infrastructure in the estuarine Gulf of Paria. These observations show that this species has well established, isolated populations at offshore oilfields with very different environments at both ends of the Greater Caribbean and provide strong support for the petro-platform relocation hypothesis relating to its introduction. They also show that N. cyanomos has considerable ecological plasticity, which may be important for its success. The location of the Trinidad population at the head of the Caribbean Current should aid its spread via larval dispersal throughout the region.