Image: FiskerForum

New stock assessment approach could lead to higher TACs

DENMARK
Thursday, December 01, 2022, 18:30 (GMT + 9)

The fish stocks in the North East Atlantic are rebuilding and our current method to assess them is not accurate, is the claim made during a recent scientific mini-symposium organised by the MSE-project group and held in Copenhagen.

According to speakers, there is a real need to revise the current approach and include fish interaction in assessments. The claim is that this would result in higher TACs.

Henrik Sparholt, a biologist and expert with a long background in assessment and monitoring of fish stocks, presented data and calculations from the MSE-project group, indicating that the North-East Atlantic actually is underfished – and that it would be beneficial if a larger amount of predatory fish such as cod, mackerel and blue whiting were caught.

The implication is that this would give remaining predatory fish opportunities to grow to a larger size because there would be sufficient prey for them when not having to compete with too many of their own species.

‘You can compare it to thinning the radishes in your garden to get the best crop,’ Henrik Sparholt said, claiming that the current method neglects to include an important part of how fish interact with each other – the density dependence.

He states that a different model is needed to calculate the so-called FMSY-reference points, which are used to determine the TACs.

Image: Researchgate/ICES TAC

‘With the available data from 53 different fish stocks we have calculated new FMSY-reference points, that are 50% higher than the current ones. That would lead to almost 50% higher TACs,’ he said.

Henrik Sparholt isn’t expecting the scientists of ICES to move quickly on recommending a switch to new methods.

‘It takes time to convince about 4000 scientists who come to this with a different perspective,’ he said.

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