These two articles were flagged to me by the excellent COAST Newsletter – you can sign up here http://www.arrancoast.com/marine-news
Both papers reveal the role of continued Nephrops – prawn fisheries on white fish stocks
Fishery-induced changes to age and length dependent maturation schedules of three demersal fish species in the Clyde
The paper published in Fisheries Research reflects on the following points;
- ‘The lengths at which haddock, whiting and cod diminished significantly during the period 1986 – 2009 with rates that were particularly rapid in the Clyde
- These may have been partly due to fishing
- The importance and scale of the Clyde Nephrops fishery increased as demersal landings declines and the majority of demersal landings since 2005 have come from Nephrops bycatch since about 2005 when the demersal fishery ceased.
- Since it appears as though fishing may have caused increasingly early maturation and substantial Nephrops fishery continues to operate in the Clyde, reversal of these changes is likely to take a long time’
To read more click here
Closure of Clyde spawning ground ‘too little, too late’ to help floundering cod stocks
ICES Journal of Marine Science ‘Measures introduced over a decade ago to protect spawning cod in the Firth of Clyde were “too little, too late”, a new study finds. Data published in the ICES Journal of Marine Science, showed no evidence that a seasonal closure of part of the Firth had led to local recovery of cod numbers or a reduction in overall mortality. The researchers from the University of Glasgow and Marine Scotland Science say implementing spawning closures on nearly collapsed stocks may be why such measures often appear to have been ineffective. The annual closure of the spawning ground was introduced in March 2001 to allow cod to reproduce without being caught by trawlers, while still allowing the targeting of scampi and scallops, in the greater part of the area. (my italics) Before the closure there was a clear seasonal peak in fishing effort corresponding to the spawning time of cod in this area with high catch rates. Placing the Clyde off limits was also intended to avoid an increase in fishing activity as a consequence of a spawning closure introduced in the Irish Sea in 2000.
Joanne Clarke, a PhD student who led the study under the supervision of Dr Peter Wright of Marine Scotland Science and Dr David Bailey at the University of Glasgow, said: “Fish that congregate at predicable locations and times to spawn are often vulnerable to over-exploitation. “Seasonal closures of fishing grounds have been implemented around the world in an attempt to alleviate such impacts, but the effectiveness of these measures is rarely tested.” Previous studies using genetics, tagging and microchemistry found that cod inhabiting the Clyde are reproductively isolated from other resident groups of the West of Scotland.
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