Genetic Effects
The farming of marine species can affect the genetic distinctiveness of local wild populations. Also, mixing farmed and wild populations may result in a loss of fitness, adaptability, and diversity or reduced survival of the wild population.
The level of effect will depend on the source of stock, the genetic profile of both farmed and wild species, and the level of interaction.
Research on the genetic profile of GreenshellTM mussels in New Zealand suggests that transferring wild green-lipped mussel spat from other areas in New Zealand to marine farms in the main mussel farming area in the country (the Marlborough Sounds) would not significantly alter the genetic profile of wild mussel populations.
There is no evidence of wild green-lipped mussel populations showing a decline in population fitness, even though mixing of farmed and wild mussel populations is likely to have already occurred in some areas. This is possibly partly due to the long-lived dispersive larval stage of GreenshellTM mussels, which suggests wide genetic mixing already occurs naturally.
Greenshell™ mussels are a species native to New Zealand. In the wild, green-lipped mussels are found on rocky coastlines all around the country, although they are most common in central and northern parts of New Zealand. They also grow in dense beds on the seafloor. Beyond our wild green-lipped mussel populations, today there are also New Zealand Greenshell™ mussel farms from Northland in the far north of the North Island to Stewart Island south of the South Island.
The majority of Greenshell™ mussels grown on marine farms in New Zealand are sourced from Ninety Mile Beach on the northwest coast of the North Island. The remainder come from Golden Bay and Tasman Bay in the northern part of the South Island.
