Hemigrapsus sanguineus, the Asian shore crab, is recognised worldwide as an invasive marine pest (IMP) species. Recent evidence suggests that it has inhabited Port Phillip Bay, Victoria, since at least 2017, and has already been deemed non-eradicable by relevant government bodies and research agencies due to the invasion likely being several generations old.
This study provides a first glance at habitat utilisation and morphometrics of the population, as well as the reproductive status and fecundity of females after significant numbers were detected at Point Cooke Marine Sanctuary in Melbourne’s west. Thus far, more females than males have been detected, 60% of the females detected over the summer months were observed to be in berry, and fecundities have ranged from 7900 to 31,900 eggs per brood. Generally, males are considerably larger than females (average masses of 20.39g and 10.9g respectively), and they shelter under rocks high and low on the shore.
As research efforts continue, the unique opportunity to document an invasion of marine pests at the relatively very early stages will be seized. The current research emphasises the sheer importance of co-operation between various institutions and citizen science to such marine and coastal management issues.