Detection of the tropical mussel species Perna viridis in temperate Western Australia: possible association between spawning and a marine heat pulse

Justin Mcdonald

doi:10.3391/ai.2012.7.4.005

Abstract

In April 2011 a single individual of the invasive mussel Perna viridis was detected on a naval vessel while berthed in the temperate waters of Garden Island, Western Australia (WA). Further examination of this and a nearby vessel revealed a small founder population that had recently established inside one of the vessel’s sea chests. Growth estimates indicated that average size mussels in the sea chest were between 37.1 and 71 days old. Back calculating an ‘establishment date’ from these ages placed an average sized animal’s origins in the summer months of January 2011 to March 2011. This time period corresponded with an unusual heat pulse that occurred along the WA coastline resulting in coastal waters >3 oC above normal. This evidence of a spawning event for a tropical species in temperate waters highlights the need to prepare for more incursions of this kind given predictions of climate change.

Highlights

Induced climate change and non-indigenous species introductions are regarded as two of the greatest threats to global biodiversity (Vitousek et al 1997; Halpern et al 2008) and have had a myriad of effects and impacts on the distribution and diversity of species (Vitousek et al 1997; Ruiz et al 2000)
While there is no direct proof of causality between the oceanic heat wave and the spawning of Perna viridis documented in this study there is a strong correlative relationship
The spawning of Perna viridis in more tropical locals such as India has been linked to changes in water temperature (Rajagopal et al 1988; Narisimham 1980)

Summary

Introduction

Induced climate change and non-indigenous species introductions are regarded as two of the greatest threats to global biodiversity (Vitousek et al 1997; Halpern et al 2008) and have had a myriad of effects and impacts on the distribution and diversity of species (Vitousek et al 1997; Ruiz et al 2000). From habitat modification (Wallentinus and Nyberg 2007), ecosystem engineering (Crooks 2002), species displacement (Erickson 1971), to competition for resources (Usio et al 2001; Vitousek et al 1997) each of these factors is a threat. It is perhaps the synergistic potential of both these threats that poses the greatest risk to marine biodiversity. Broadcast dispersal of planktonic larvae, the capacity to settle on a variety of hard surfaces and an ability to survive in a wide range of depths (from the intertidal to 42m) allows P. viridis to outcompete existing native assemblages, resulting in changes to community structure and trophic relationships (NIMPIS 2011)

Methods

Results

Conclusion