Preventing the Costs of Invasive Alien Species (IAS) In Barbados and the OECS Countries – Marine Risk Assessment Report

Excerpt Report Summary:

Invasive species are one of the leading causes of biodiversity decline worldwide and can have severe, detrimental impacts on human health and the economy. We define invasive species here as any non-indigenous species that is brought by humans to a location where it has never occurred before and has substantial, negative impacts on native biodiversity and/or human systems. Prevention is by far the cheapest and most effective form of invasive species management. It is therefore not surprising that risk assessments are increasingly being used to identify high risk vectors and/or non-native species that should be prioritized for management.

Over 100 exotic marine species have been introduced to the wider Caribbean region. It is likely that many of these species will, at some point, enter Barbados and the Organization of Eastern Caribbean States (OECS) countries (i.e., the subregion) either by natural dispersal or via similar major transport vectors. Given the above, in this report we first conducted a retrospective relative risk assessment of vectors for the wider Caribbean.

The findings from this assessment were subsequently used to predict the relative importance of major transport vectors to the subregion in the short to medium term. We also used the retrospective assessment to identify potential non-native species that could become invasive in the subregion. In this latter instance, we paired stratified, random sampling with an internationally recognized, semi-quantitative species risk assessment approach.

Several major findings emerged from our analysis. We found that, similar to the regional retrospective assessment, the transport vectors that pose the most risk to the subregion in the future are the aquarium trade, shipping (i.e., ballast water and biofouling) and fisheries (inclusive of aquaculture). Moreover, we discovered that a large percentage of species introduced to the region (and that can therefore potentially enter the subregion) could not be ascribed to any particular vector. Thirty-two species were assessed for their potential to become invasive in the subregion and were placed on one of three invasive species watch lists: red (high likelihood of becoming invasive), orange (medium likelihood of becoming invasive) and green (low likelihood of becoming invasive). The majority of species posed a medium risk of becoming invasive. However, four species were highly likely to become invasive if they should enter the subregion. These included (in descending order of risk): (1) the Giant tiger prawn, Penaeus monodon, (2) the Ribbon sea lettuce, Ulva reticulata, (3) the Spotted scat, Scatophagus argus, and (4) the Atlantic sea nettle, Chrysaora quinquecirrha. This report is a preliminary assessment of the key threats to the subregion and should be used as a guideline for more in-depth analyses.

Authors: Nicola S. Smith (project lead), Amanda R. Gray, Jordan Hollarsmith and Isabelle M. Côté

Read the details of this risk assessment in the report: