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The distribution and relative abundance of the invasive Northern blue mussel, M. galloprovincialis, in New Zealand: management implications

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thesis
posted on 2023-09-26, 23:59 authored by Ian BlixtIan Blixt

Biological invasions are a growing problem on a global scale, are capable of causing moderate to severe damage, and are most often associated with human activity. This is particularly true in the marine environment, where there are many well documented cases of non-indigenous species (NIS) spreading via maritime traffic or undergoing a range expansion associated with ocean temperatures continuing to increase. The blue mussel Mytilus galloprovincialis, recognized a one of the most successful NIS globally, is one such species that is spreading in such ways. However, in the Southern hemisphere research over the past decade has shown that there are two lineages of M. galloprovincialis present, likely different species, one native to the Northern hemisphere and one native to the Southern hemisphere. In New Zealand, the Northern lineage of M. galloprovincialis (MgN) has successfully invaded and poses a unique threat to native biodiversity as there are higher rates of introgression with the native Southern lineage of M. galloprovincialis (MgS) than elsewhere in the Southern hemisphere. However, whether MgN is causing other ecological damage in New Zealand is still unknown. Therefore, the main objective of Chapter 2 is to provide a preliminary description of the distribution and relative abundance of MgN in New Zealand, and how abiotic factors may be influencing this invasion. Also, it was recently reported that M. galloprovincialis causes severe economic losses to the native greenshell mussel Perna canaliculus aquaculture industry. However, these reports did not differentiate between the native and invasive blue mussel lineages. The main objective of Chapter 3 then is to provide a description of the distribution and relative abundance of MgN in the Marlborough Sounds, the primary P. canaliculus aquaculture region in New Zealand. The results of Chapter 2 indicate that several abiotic factors significantly influence the relative abundance of MgN across New Zealand; and that intranational maritime traffic is a more important vector of spread than international maritime traffic. The results of Chapter 3 show that the relative abundance of MgN was approximately equal across aquaculture facility sites and adjacent shore sites, but that increased habitat space on the grow-lines of aquaculture facilities has resulted in significantly increased overall abundances of both MgN and MgS. This means that there is a much larger MgN population in this region than would be otherwise present due to the aquaculture facilities. Overall, these results indicate that human activity in New Zealand is significantly affecting the MgN invasion therein. These findings are important for both management purposes and for guiding future research.

History

Copyright Date

2020-01-01

Date of Award

2020-01-01

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

CC BY-NC-ND 4.0

Degree Discipline

Marine Biology

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Masters

Degree Name

Master of Science

ANZSRC Type Of Activity code

1 PURE BASIC RESEARCH

Victoria University of Wellington Item Type

Awarded Research Masters Thesis

Language

en_NZ

Victoria University of Wellington School

School of Biological Sciences

Advisors

Gardner, Jonathan