Catch Advice 2018 Ireland: Scientific Report

seeking

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Looking good again, from a salmon population point of view - bigger counters within range on average (Fig 3, Fig 4 [though grilse> MSW] Fig 5 RHS, c.f. Fig 5 Middle where some of the smaller rivers [i.e. more susceptible to anthropogenic impacts etc.] are clearly struggling [despite CCR/C&R etc]), rod catch within range and no sign of collapse ??????).

One of the most glaringly obvious shortcomings is the paucity of reliable science:

a. ER estimates vary by up to 200% and therefore there is the potential for any estimate to be dependent on a guess.

b. No catch analyses or presentations, hence one can't tell if there's a problem with catches.

c. No account of rod effort taken into account, so ditto.

d. Seeming overdependence on electrofishing of parr, which do not seem to reliably reflect either smolt output or adult abundance.


The political nature of Chapter 9 is a little chilling IMHO. Instead of relying on empirical scientific evidence, the overreliance on "black box statistical gobbledygook" CLs the output of which often appears to rely on guesstimates (GIGO) can't be great.

Still, very interesting in a management transparency context IMHO. Thanks for posting.
 

KerrySalmon

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Looking good again, from a salmon population point of view - bigger counters within range on average (Fig 3, Fig 4 [though grilse> MSW] Fig 5 RHS, c.f. Fig 5 Middle where some of the smaller rivers [i.e. more susceptible to anthropogenic impacts etc.] are clearly struggling [despite CCR/C&R etc]), rod catch within range and no sign of collapse ??????).

One of the most glaringly obvious shortcomings is the paucity of reliable science:

a. ER estimates vary by up to 200% and therefore there is the potential for any estimate to be dependent on a guess.

b. No catch analyses or presentations, hence one can't tell if there's a problem with catches.

c. No account of rod effort taken into account, so ditto.

d. Seeming overdependence on electrofishing of parr, which do not seem to reliably reflect either smolt output or adult abundance.


The political nature of Chapter 9 is a little chilling IMHO. Instead of relying on empirical scientific evidence, the overreliance on "black box statistical gobbledygook" CLs the output of which often appears to rely on guesstimates (GIGO) can't be great.

Still, very interesting in a management transparency context IMHO. Thanks for posting.
Don't really agree with all you say. The graphs of the fish counters are relatively accurate and the graph comparing MSW and 1SW are a good indicator of general trend. Have a proper look at same. Exploitation rates are made from reference rivers with counters but I agree that rod effort might be a problem.There is a decline as some of these rivers have no commercial fisheries near them post 2006 but more importantly regarding 2SW fish which by and large were largely unaffected by any commercial fishery pre 2006 and post this date and there is a distinct decline. Interesting over the time series it really illustrates that grilse survival is indicative of MSW fish following year. Electro fishing demonstrates really the stocks of fry and parr but is only indicative of spawning stocks the previous year or a limited time period longer than this. The data generated in regard to conservation limits is always being improved with habitat surveys conducted annually. Smolt numbers certainly have dropped in some catchments due to habitat and water quality compromise but where smolts can be counted (Wild) the survival of these is around 5% with some years lower. Last year was in the order of 7.5%(1SW) and the spring run is far better this year in the majority of rivers thus indicating a positive link with MSW fish.
 
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