Getting the line on herring

If you can't drop a line and catch a herring, you must be a very unlucky angler, says Murdoch fish biologist Dr Margaret Platell.
      That's one thing we do know about one of WA's most popular fish, but there are lots of other details that are only just emerging from a Murdoch research project funded by the federal Fisheries Research and Development Corporation.
      Dr Platell, who is fish research coordinator at Murdoch, said although we know herring are found along the southern half of Australia, where they are heavily fished by both recreational and commercial fishers, the proper management of the fisheries for this popular species has been hampered by a lack of basic biological knowledge.
      Recently the fisheries authorities in both WA and South Australia have become concerned about herring fishing. Fisheries WA and its South Australian counterpart have commissioned research into this important species. At present, the authorities and researchers from Murdoch University are finalising their three-year study.

They are likely to spawn when they are two to three years old, and during the winter in waters between Perth and Albany.

      Murdoch's fish expert, Professor Ian Potter, is leading the research on the biology of the herring. His researchers are gathering base-line data about the fish -- the size and age structure of the population, size and age at maturity and the time, frequency and location of spawning.
      With this data, and other data collected by the fisheries authorities, a population model will be able to be built for herring. This model will be used to make decisions about the management of the herring stocks, such as imposing size limits or by reducing the current bag limit of 40 fish per day.
      Murdoch research assistant David Fairclough has been gathering the information by netting fish at various spots along the lower west coast of WA, and by getting fish from the commercial operators.
      Dr Platell said that additional information had been provided by recreational anglers who had been very helpful about giving the researchers their fish.
      "They fillet the fish they catch and give us the head and other important parts," she said.
      From those remains, the researchers have been able to determine the age, size and sex of the fish, whether or not it is spawning, and relate this information to the location where the fish was caught.
      So far it is known that herring may reach an age of more than 10 years.
      They are likely to spawn when they are two to three years old, and during the winter in waters between Perth and Albany. The young fish that result from these spawning events can end up either in WA or SA, depending on the strength of the tropical Leeuwin Current, which sweeps south along the WA coast and around to South Australia.

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