IN THIS edition, let’s talk about the humble pilchard. It’s the mainstay for many a bait fisher in our region that can be used to target a range of species including tailor and snapper.
Pilchards belong to the family Clupeidae and there are about 200 species worldwide. The common name of pilchard and sardine are used interchangeably for several species. The Australian species is referred to by the scientific name of Sardinops sagax.
The species can be found from about Bundaberg southwards around the Australian mainland and northern Tasmania to about Shark Bay in Western Australia. There are four different subpopulations with fish in NSW and southern Queensland forming a separate single subpopulation.
Pilchards can occur from the near surf zone to depths of well over 100m. Despite being a relatively small fish, pilchards can reach up to nine years of age. By comparison, there are very few tailor caught in Queensland that are that old.
Large schools of pilchards migrate into Queensland for spawning, with the spawning period centred on June and October. They are mature at about two years of age.
Depending on body size, female fish produce between 10,000 to 45,000 eggs per spawning event. Larvae that are produced are thought to float southwards on the East Australian Current – just like Nemo did in Finding Nemo. In more southern latitudes, spawning occurs at different times. Schools of pilchards can travel up to 30km per day.
Most pilchards that are caught commercially for bait are captured by purse seine netting in NSW and the waters of southern and Western Australia. This is a targeted method of fishing that typically relies on detecting schools of fish by sonar prior to deployment of the net.
In 1995 and 1998/99, Australian pilchard populations were decimated by a virus (a type of herpes virus) that was introduced into Australia. This led to a mass die-off with hundreds of millions of dead pilchards washing up on beaches and creating a sad and smelly environmental problem. Mortality rates were as high as 75 per cent of the population in some areas.
The significant and rapid reduction in pilchard populations resulted in impacts on their predators including penguins in cooler waters that had higher mortality rates and failed to breed due to food shortages. The virus is now endemic in Australian pilchard populations, but mass mortality no longer occurs.