Salmon smolt by-catches in Mackerel/herring trawlers?

Trooperboyo

Anyone have any thoughts on how this could be managed? I know that for every 4kg of fish caught 1 salmon smolt is caught.

I was thinking maybe they should introduce a fishing season, where certain parts of the year are off limits for fishing particulary when smolts are migrating out to sea. I was thinking they could designated this in certain areas known for smolt migration. Enforcement and policing is a totally seperate issue.

Anyone have any thoughts on this?

SafeSurfer

It's certainly worth looking at. The smolt run will be starting soon.

muracan

Where did you get that statistic?Pure rubbish!:mad:

The Irish mackerel quota is approx 70000 tonnes this means, by your calculations there should be 1700tonnes of smolts (100g av) landed too!!!!!
I work in pelagic factory on a grading machine and have NEVER seen 1 smolt or salmon landed by a mackerel trawler or by any other pelagic trawler for that matter.
I'm sorry but this is the sort of bull that is believed by many that is so in accurate that it can create huge problems for fishermen.:mad:

You need to educate yourself before posting such drivel........

Trooperboyo

The numbers of Atlantic salmon returning to spawn has halved in since the 1970’s. This has been put down to various factors such as Disease, over fishing, the rise in illegal fishing, water quality issues, mismanagement by fisheries, maritime fishing activities and climate change.

Not a lot is known as to why salmon are dying at sea but it has been put down to two factors: Climate change and Fishing activites. Climate change is responsible for changing ecosystems in the Atlantic and North Sea, limiting available food for salmon. Climate change is changing the temperature profiles in the Atlantic, some of which belive salmon use to navigate back to their natal stream. Climate change may be changing salinity valuse by increased rainfall or melting snow, which changes the saline concentrations before the post smolts left the area. Fishing activities in particular over fishing and bad practices are demolishing fish stocks in the atlantic and north sea, and is suspected and documented that makerel/herring fishing is landing post smolts as by-catches. There is an array of scientific literature and studies to back this up. The statistic I mentioned was one of the figures estimated in those studies.

With the ban of the mixed stock fisheries in Ireland in 2007 there has been no significant change in stocks in Ireland. I suspected there could be a move to protect smolts at sea to improve salmon stocks if they stay in the state that they are presently.

muracan wrote: »

Where did you get that statistic?Pure rubbish!:mad:

There is a lot of scientific literature to back this up. No links, just literaure and if you really want I could give reference.

The Irish mackerel quota is approx 70000 tonnes this means, by your calculations there should be 1700tonnes of smolts (100g av) landed too!!!!!

Maybe that's because salmon smolts are in no great concentration in the Irish box:)

I'm sorry but this is the sort of bull that is believed by many that is so in accurate that it can create huge problems for fishermen.:mad:

It is well documented that smolts are being caught in great numbers in the North Sea

You need to educate yourself before posting such drivel........

I really should say the same to you:rolleyes:
Firstly there is no need to make such petty and small-minded remarks at me, you have gotten the wrong end of this and have little or no understanding about salmon smolt activity. Secondly, I'm writting a thesis on salmon conservation and management so don't start lecturing me on how educated I am or not.
_______________________________

Anyone else have any thoughts on this subject?

fontanalis

I worked ina factory and the only salmon I saw were adults through scad, and this was very rare.

rushnaldo

Have to agree. Im in the industry also and a keen angler and never seen salmon or smolts through the mackerel or herring bags or demersal gear for that matter. This past fee years the tank boats are using electronic jigging machines to test shoal size by hook before they decide to tow on it instead of catching a big bag of underside fish. The north sea is frequented by the big Irish vessels and never seen salmon or smolts in the gear. Fish are like birds and the same species tend to shoal together. The banning on the drifting for salmon was heralded as a great thing and the government paid compo to all the ex salmon men but in my opinion this is destroying other species. Let me explain. In Donegal bay the ex salmon men all still have their boats, no jobs, and plenty of spare time and a big cheque. Beltronic jiggers are everywhere hammering out 20 boxes of mackerel in a few hours and now the 400 tonne inshore quota on them has the men heading out to the offshore wrecks with one small craft hitting 40 boxes of pollock with the jiggers last week. As for the weather and climate change explanations for salmon decline I think too much is being thought into it, its much simpler than that, how is it that the stocks are not rising even though the fishing has stopped? The seal population graph is rising rapidly and there lies your answer, my opinion just and im interested in everyone elses too.

Trooperboyo

The seal population graph is rising rapidly and there lies your answer, my opinion just and im interested in everyone elses too

And cormorants too, interestingly there is legislation in place that protects salmon and it's predators. However there is no way of culling/mitigating these animals from an area if they are considered a pest in that area under present legislation. It's estimated that over the last 25 years that the cormorant population has increased 20 fold and their population stands at 1.7-1.8 million in the EU.

It's debatable how much salmon are taken by seals, in fact seals were known to use fishermens nets to their advantage to catch salmon. A survey of dead seals carcases indicated 26% had consumed salmon, while a recent survey of faecal matter indicated a negligible amount feed on salmon. However these surveys are very subjective since the seal may or may not consume the head of the salmon (to see if the otoliths shows up).

I came across a study indicating esturies and bays with higher populations of Sand eel resulted in predation of smolts from marine fish.

muracan

Firstly, I have no intention of rowing with you Trooper, or being small minded...however your first post was very broad and vague as regards the North Sea etc. and got me riled as a result.
I too have studied salmon in my time and would suggest, as the other lads have said, that seals are the biggest threat to salmon stocks at present.
Being from Cork I have seen seals in the estuaries of most of the main rivers ie Lee, Blackwater,Bandon and Ilen......they don't have to depend on robbing netsmen no longer.If only a few Orcas could keep them at bay or better still distemper or 303 rifle!

pmurphy00

the banning of drift net fishing hasn't resulted in an increase in salmon stocks as the nets were not the major problem.

they were however by far the easiest targets.

the seal population on the west coast (which is where im familiar with)
is causing an incredible problem..

i also believe that cormorants are quite destructive.

i honestly believe in 30 years we will laugh at the lack of knowledge
we have in relation to salmon. we simply don't understand.
during years of huge numbers of salmon being netted nobody could predict
how the future years would project. even in the 70's there were years with
draft nets that had dismal returns. yet in the 80's there was huge numbers of fish caught*..

my opinion is that the scientific knowledge on this issue is not showing the full picture. i hope some day it will.

(*im refering to the area which i live on the west coast.)

coolwings

pmurphy00 wrote: »

the banning of drift net fishing hasn't resulted in an increase in salmon stocks as the nets were not the major problem.
....

That is a big assertion to make.
It appears you are repeating misinformation spread by a netting lobby, or trying to make some sort of case for netsmen.
Here is some information:
The other countries that protested the Irish drift net overharvest used scientific evidence to back up their claims. Irish drift nets were not just eradicating Irish salmon but scottish, welsh and other countries salmon too. Do you think these countries would have opposed Irish nets if Irish nets were not the problem?

Monofilament nets which took 98% of all returning salmon were the primary problem due to the numbers of fish they took being unsustainable.

There are of course other problems too.
It is silly to deny that, but it is misleading to assert that other causes were the main cause.
Of course seals, anglers, otters, and disease took too many of the remaining 2%.
But that's all they got a shot at seeing as there was an invisible miles long monofilament salmon killing net sticking out into the sea from every significant headland on the north west, west, south west and south east Irish coastline.

The dearth of salmon in the most easterly rivers is itself prima facie evidence of the cumulative effect of nets as the fish attempt to follow the coastline anti clockwise around Ireland. Returning Liffey and Slaney salmon for example had to pass more nets than eg Connemara or Donegal salmon.
http://www.oireachtas.ie/documents/committees29thdail/commmarnatressalmonnettingsubmissions/document26.doc

If the drift nets had settled for killing less than 98% of the species, they might still be legal.

You might look at river counter reports and catch reports before and after drift nets were banned.
The other factors are still there. This makes a strong case that improvements are due to drift net reduction. Net marked fish are still running the rivers, so we know what is being done where patrols are insufficient.

rushnaldo

River pollution and agricultural chemicals etc must be having drastic effects nowadays also that were unheard of back in the 80's when driftmen were reaping the big rewards. That and the over protection of other wildlife along the rivers like birds and otters etc upsetting the natural balance. Would most damage be done at sea or ib rivers? I'd have to say rivers and dont get me started on those stupid weirs and dams

Trooperboyo

muracan wrote: »

Firstly, I have no intention of rowing with you Trooper, or being small minded...however your first post was very broad and vague as regards the North Sea etc. and got me riled as a result.
I too have studied salmon in my time and would suggest, as the other lads have said, that seals are the biggest threat to salmon stocks at present.
Being from Cork I have seen seals in the estuaries of most of the main rivers ie Lee, Blackwater,Bandon and Ilen......they don't have to depend on robbing netsmen no longer.If only a few Orcas could keep them at bay or better still distemper or 303 rifle!

Sorry there old chap, I got the feeling you might have been trolling (or trawling:pac:). I should have been more specific, but I was hoping that someone might have had an idea about potential by-catches.

rushnaldo wrote: »

River pollution and agricultural chemicals etc must be having drastic effects nowadays also that were unheard of back in the 80's when driftmen were reaping the big rewards. That and the over protection of other wildlife along the rivers like birds and otters etc upsetting the natural balance. Would most damage be done at sea or ib rivers? I'd have to say rivers and dont get me started on those stupid weirs and dams

There is a lot of strict legislation and regulation regarding water quality and Agri practices. From reading recent epa water quality reports, Irish surface waters have been by and large good quality. The Water framework directive, if achieved, would be brilliant with regard to salmonid water quality.


On the issue of seals, I'm still not convinced that they are causing any great damage. Its only a small percentage that travel up the river to feed on salmon, analysis of their feaces indicate only a small number are feeding on salmon. However this analysis is dependant on how the seal eats the salmon; whether they eat the head of the salmon or just eat the flesh and then disgard the fish (the indicator is in the head section of the salmon). The behavior of seals in the presence of numerous salmon indicate that they mostly eat the whole salmon (i.e they were set lose in a cage full of salmon). I think there is a major problem with cormorants, they are more or less a pest and cannot be culled to reasonable population since the Wildlife act protects them.

With regards the Drift net ban, it would be mostly Southern Irish fisheries who should be seeing the huge benefits. I am looking at salmom population estimates in the west of Ireland and any increases in populations since the ban are neglibale. More time is needed to see if the ban was effective, especially when four years have passed since the ban.

There's also the issue of Salmon farms, in particular escapees mixing with wild stock. Farmed salmon have been shown to have lower survival/return rates compared to wild stock.

ironbluedun

pmurphy00 wrote: »

the banning of drift net fishing hasn't resulted in an increase in salmon stocks as the nets were not the major problem.

they were however by far the easiest targets.

Not correct.

ironbluedun

pmurphy00 wrote: »

i also believe that cormorants are quite destructive.

I also believe that humans are quite destructive, you know the ones who still have illegal drift nets at sea.

Zzippy

coolwings wrote: »

That is a big assertion to make.
It appears you are repeating misinformation spread by a netting lobby, or trying to make some sort of case for netsmen.
Here is some information:
The other countries that protested the Irish drift net overharvest used scientific evidence to back up their claims. Irish drift nets were not just eradicating Irish salmon but scottish, welsh and other countries salmon too. Do you think these countries would have opposed Irish nets if Irish nets were not the problem?

Monofilament nets which took 98% of all returning salmon were the primary problem due to the numbers of fish they took being unsustainable.

There are of course other problems too.
It is silly to deny that, but it is misleading to assert that other causes were the main cause.
Of course seals, anglers, otters, and disease took too many of the remaining 2%.
But that's all they got a shot at seeing as there was an invisible miles long monofilament salmon killing net sticking out into the sea from every significant headland on the north west, west, south west and south east Irish coastline.

The dearth of salmon in the most easterly rivers is itself prima facie evidence of the cumulative effect of nets as the fish attempt to follow the coastline anti clockwise around Ireland. Returning Liffey and Slaney salmon for example had to pass more nets than eg Connemara or Donegal salmon.
http://www.oireachtas.ie/documents/committees29thdail/commmarnatressalmonnettingsubmissions/document26.doc

If the drift nets had settled for killing less than 98% of the species, they might still be legal.

You might look at river counter reports and catch reports before and after drift nets were banned.
The other factors are still there. This makes a strong case that improvements are due to drift net reduction. Net marked fish are still running the rivers, so we know what is being done where patrols are insufficient.

He mightn't be the only one repaetnig misinformation! Drift nets only took in an average year 50-60% of returning grilse, in an exceptional year it was 70%. As the drift netting season didn't start until June, spring salmon were not intercepted by drift nets, so the percentage of the whole salmon stock intercepted would have been lower than that 50-60%. Its still a big figure though.

This reminded me of a conference on salmon I attended about 10 years ago, in Dublin, where there was a Q&A session at the end. Niall O'Maoileidigh of the Marine Institute was asked what percentage of salmon were taken by drift nets, and he replied with the above figures - 50 to 60%. Whereupon one outspoken angler in the audience, with an obvious talent for maths, proclaimed "You can double that!" :eek:

ironbluedun

Zzippy wrote: »

He mightn't be the only one repaetnig misinformation! Drift nets only took in an average year 50-60% of returning grilse, in an exceptional year it was 70%. As the drift netting season didn't start until June, spring salmon were not intercepted by drift nets, so the percentage of the whole salmon stock intercepted would have been lower than that 50-60%. Its still a big figure though.

This reminded me of a conference on salmon I attended about 10 years ago, in Dublin, where there was a Q&A session at the end. Niall O'Maoileidigh of the Marine Institute was asked what percentage of salmon were taken by drift nets, and he replied with the above figures - 50 to 60%. Whereupon one outspoken angler in the audience, with an obvious talent for maths, proclaimed "You can double that!" :eek:

i agree drift nets did and still do a lot of damage, no denying that, i dont think it was 98% or anything like that, but a high percentage....truth is that it was a lot of factors, that we all know, but yes drift nets were a primary factor. But there is no point in blaming them alone, anglers also have a lot to answer for.

fontanalis

ironbluedun wrote: »

i agree drift nets did and still do a lot of damage, no denying that, i dont think it was 98% or anything like that, but a high percentage....truth is that it was a lot of factors, that we all know, but yes drift nets were a primary factor. But there is no point in blaming them alone, anglers also have a lot to answer for.

Has there been any developments in catch & release in recent years? I'd say a lot of anglers wouldn't be too keen on it.

ironbluedun

fontanalis wrote: »

Has there been any developments in catch & release in recent years? I'd say a lot of anglers wouldn't be too keen on it.

yes.......and yes again.

coolwings

About that figure for net catch. I worked it out for myself a long time ago.
It is not an officially available figure.

It was the result of calculations I made for myself a couple of years after the government minister of the day made an order permitting the use of monofilament net. This was an identifiable tipping point leading to destruction of Irish rivers, because the existing nets could be avoided by the salmon in bright conditions, but monofilament nets had a greater degree of invisibility.
Mono nets were also cheaper and could be left out in bad weather when boats could not go out. So the effective netting days in a year rose substantially with that decision.
Also with more nets laid prior to storms and never recovered, lost nettage increased significantly. A lost mono net would continue to fish as a ghost net.

I had the official catch returns, official guesstimates of illegal catch, and the fish counter returns for several rivers.

My catch percentage was calculated by taking river fish counter returns after periods of calm weather (some fish avoid nets), normal weather (nets are more efficient and take more) and violent weather (boats under a certain length stay in harbour (net catch falls).
I worked on the hypothesis that if you measure what passes the nets in favourable netting weather, compare to what gets past when the nets are off, the increase in the salmon runs through fish counters represents what nets normally take.

A 90%+ seems high, but they virtually eliminated east coast Irish salmon. Consider the official catch of 60-70% and ask "how many more salmon were offloaded onto foreign vessels at sea, and never landed in Irish ports?" Subsequent investigations discovered these evasion practises of some commercial fishermen.

Zzippy

coolwings wrote: »

About that figure for net catch. I worked it out for myself a long time ago.
It is not an officially available figure.

It was the result of calculations I made for myself a couple of years after the government minister of the day made an order permitting the use of monofilament net. This was an identifiable tipping point leading to destruction of Irish rivers, because the existing nets could be avoided by the salmon in bright conditions, but monofilament nets had a greater degree of invisibility.
Mono nets were also cheaper and could be left out in bad weather when boats could not go out. So the effective netting days in a year rose substantially with that decision.
Also with more nets laid prior to storms and never recovered, lost nettage increased significantly. A lost mono net would continue to fish as a ghost net.

I had the official catch returns, official guesstimates of illegal catch, and the fish counter returns for several rivers.

My catch percentage was calculated by taking river fish counter returns after periods of calm weather (some fish avoid nets), normal weather (nets are more efficient and take more) and violent weather (boats under a certain length stay in harbour (net catch falls).
I worked on the hypothesis that if you measure what passes the nets in favourable netting weather, compare to what gets past when the nets are off, the increase in the salmon runs through fish counters represents what nets normally take.

A 90%+ seems high, but they virtually eliminated east coast Irish salmon. Consider the official catch of 60-70% and ask "how many more salmon were offloaded onto foreign vessels at sea, and never landed in Irish ports?" Subsequent investigations discovered these evasion practises of some commercial fishermen.

Way too many variables and guesstimates in that method to be in any way reliable. The 60-70% figures I quoted were based on research by the Marine Institute, with tagged smolts and tag recaptures from commercial netsmen, anglers and actual data from counters and traps. If driftnets took 90%+ of returning salmon we should have seen a huge increase in returning fish following the ban, however it was a smaller increase but thankfully has continued to increase since. This year is the first full lifecycle since the ban - the progeny of fish who spawned in 2007 will be returning this year - so I expect, and hope, to see a bigger increase in grilse this year.