Cryptic introduction #Biosecurity

Last week in our series of Topics, we discussed cryptic introduction. Here at Ocean Wolf, we think to consider two general different forms of cryptic introduction:
(1) the presence of a similar-looking taxa masks the introduction of a non-native species, or (2) the same species is introduced from different locations. But how is it possible that a species could be introduced from different (not neighbouring) locations? To explain this possibility, we need to look at "step-stone-introduction". Carlton introduced the concept of step-stone-introduction with his publications in 1996 and 2000.
For this concept, we need to differentiate between donor- and recipient-region. At a donor region, a species is established; in this area on a vessel, some individuals could foul or be taken up with ballast water. The individuals or gametes could be released into the water in the recipient region. Suppose the released species can form a stable population and successfully reproduce. In that case, the region becomes a donor region as well. This new population will initially have a limited gene pool as a subset of the original population. However, through genetic mutations and further introduction, the gene pool will increase and differ from the original population, which also continues to evolve. In some cases, this could even lead to speciation and the two populations drift that far apart that we could have two species.
However, back to the step-stone- and cryptic introduction, once the new location becomes a donor region, the species can again travel through haul fouling or ballast water to the next region. We have a new donor region once it arrives in the recipient region and forms a stable population. This form of step-stone-introduction can wander from coastline to coastline. This introduction concept explains how a species could be introduced to a region from multiple donor regions. A prime example could be the globally invasive Ficopomatus enigmaticus (Fauvel, 1923), which has also been causing problems in New Zealand since the 60's. This species is all over the world known as one of the top 100 most invasive species, but we still need to find out where this species originated. Hence, colleagues from the Australian Museum, Flinders University, Sequench and Ocean Wolf were and are looking into mapping F. enigmaticus and its tropical cousin F. uschakovi (Pillai, 1960) around the world to uncover subspecies and the introduction path.
If you want to know more about hashtag#Step-Stone-Introduction, hashtag#Cryptic-Introduction, hashtag#Biosecurity, hashtag#Speciation let us know!
www.ocean-wolf.com


Images
Ficopomatus enigmaticus in the Ahuriri estuary - Hawkes Bay Today 2nd of Nov. 2017