Dr Jaffa analysed data of rod-caught fish going back to 1952 (data derived from catch returns self-reported by recreational anglers). He has broken down those catches into \u2018grilse\u2019 \u2013 salmon that have spent just one winter at sea before returning to their river of birth \u2013 and salmon that have spent more than one winter at sea before making their return to their river to breed.<\/p>\n
Dr Jaffa has then examined numbers separately for the east coast of Scotland, where the rivers tend to be slower and longer, and the west coast, where in the more mountainous terrain rivers are shorter and steeper before reaching the sea. It is on the west coast where most of the intensive salmon farming is located.<\/p>\n
While acknowledging that overall salmon numbers returning to Scottish rivers have fallen, Jaffa claims that reported catches of \u2018grilse\u2019 have not declined, even on the west coast leading him to declare that salmon farming cannot be responsible for falling numbers.<\/p>\n
Dr Jaffa concludes that fluctuations in wild salmon stocks are caused by \u2018cyclical patterns\u2019 resulting from changing sea temperatures and variations in marine growth rates \u2013 not the presence of farms.<\/p>\n
![\""underneath\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/22\/2022\/01\/salmon_farm_argyll-b678fcf.jpg?quality=90&resize=620%2C397"\" "\\"\"Fish\\"")
<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Dr Jaffa does acknowledge though that his view is based on limited data and does require further research. As he writes in his paper:<\/p>\n
\u2018In total there are 109 fishery districts in Scotland, of which 59 are located in the NW Highlands. The data presented herein has been selected for 4 fishery districts that most clearly illustrate the importance of disaggregation of the Scottish salmon landings data into morph types [grilse and salmon].\u2019<\/p>\n More related content:<\/p>\n <\/p><\/div> Andrew Graham-Stewart, Director of Salmon & Trout Conservation (Scotland) goes further regarding the data upon which Dr Jaffa has based his analysis.<\/p>\n \u201cDr Jaffa\u2019s latest output focusses on just four west Highland rivers \u2013 which are far from representative,\u201d says Graham-Stewart. \u201cThe reality on the ground is that the great majority of smaller rivers in the west Highlands and Islands have lost almost all of their wild salmon since the exponential growth of salmon farming occurred from the 1990s.<\/p>\n \u201cAcross the northern hemisphere the growth of intensive salmon farming has invariably coincided with the collapse of wild salmon runs.\u201d he continues. \u201cSalmon farms are efficient breeding reservoirs for parasitic sea lice and as such they are a major, indeed lethal, problem for wild salmon \u2013 and sea trout \u2013 as they migrate to sea. There is international consensus on this with numerous peer-reviewed papers clearly demonstrating an impact.\u201d<\/p>\n Andrew Graham-Stewart also cautions against the use of recreational anglers catch reports to distinguish between grilse which have spent one winter at sea, and salmon which have spent more. Salmon are complex animals and size alone is not reliable \u2013 a scale sample and microscopic examination is one reliable method.<\/p>\n \u201cMost anglers are unable to differentiate between large grilse and small salmon and accordingly official declared catches for grilse and salmon are based on nominal, often estimated, weights, which can vary from year to year and from river to river, rather than any reliable biological difference.\u201d says Graham-Stewart.<\/p> Wild salmon and sea trout numbers in Scottish rivers have fallen by 70% over the last two decades. Global populations of Wild Atlantic Salmon have fallen from between 8 and 10 million in the 1970s to 3 million today.<\/p>\n Most scientists agree that there are many, complex reasons for the fall in salmon numbers, of which intensive, open-net fish farming is one. Other factors include climate change, loss of habitat in rivers to support life cycles and instream barriers such as weirs preventing migration.<\/p>\n Sea lice (Lepeophtheirus salmonis<\/em>) are a copepod crustacean that have lived in our seas for millions of years. The larvae are parasitical, attaching themselves to a host salmon and feeding off its skin and blood. While not thought to be harmful when ingested by humans, sea lice can cause huge damage to the fish, leaving open wounds and legions on its body that make the fish unmarketable. In the wild, a louse \u2013 which is less than a millimetre long \u2013 can struggle to find a host. However, with the high concentrations of fish kept in open net pens \u2013 where the fish are separated from the open sea by just a net \u2018cage\u2019 \u2013 they have rich pickings to live on.<\/p>\n Most scientists agree that lice from farmed salmon in open net pens do pass to wild fish. Research has shown that an infestation of 10 to 12 lice is likely to have fatal consequences. A farm where the fish have 5 mature female lice can release as many as 3 billion sea lice larvae per month.<\/p>\n The Scottish Government summarised the available science: \u2018The body of scientific information indicates that there is a risk that sea lice from aquaculture facilities negatively affect populations of salmon and sea trout on the west coast of Scotland.\u2019<\/p>\n The salmon farming industry has been rocked in recent years by images of grotesquely deformed fish in crowded pens that have been half-eaten alive by sea lice appearing in the national media and posted regularly on social media by campaigners.<\/p>\n Salmon farming is big business in Scotland. A Marine Scotland-commissioned report reveals that it is worth at least \u00a3885-million and supports 11,700 jobs, many in rural, coastal communities where work opportunities can be scarce.\u00a0The report also found that Scottish salmon represents the UK\u2019s largest food export by value.<\/p>\n Salmon & Trout Conservation is campaigning for the end of open-net farming which it claims is unsustainable, and the further development of closed containment systems, which completely separates the farmed fish from the open water. Theoretically at least, this could be done inland.<\/p><\/body><\/html>\n By Andrew Griffiths Published: Wednesday, 05 January 2022 at 12:00 am New research claiming that intensive salmon farming off the west coast of Scotland has no harmful effects on wild salmon populations has been dismissed by a leading conservation organisation as \u201cmanipulating and cherry-picking statistics\u201d. Many fish biologists maintain that farmed salmon have a negative […]<\/p>\n","protected":false},"author":24,"featured_media":260,"template":"","categories":[1],"acf":{"readingTimeMinutes":"6"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/45\/2022\/01\/controversial-new-research-on-the-impact-of-salmon-farms-dismissed.jpg",1024,683,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/45\/2022\/01\/controversial-new-research-on-the-impact-of-salmon-farms-dismissed-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/45\/2022\/01\/controversial-new-research-on-the-impact-of-salmon-farms-dismissed-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/45\/2022\/01\/controversial-new-research-on-the-impact-of-salmon-farms-dismissed-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/45\/2022\/01\/controversial-new-research-on-the-impact-of-salmon-farms-dismissed.jpg",800,534,false],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/45\/2022\/01\/controversial-new-research-on-the-impact-of-salmon-farms-dismissed.jpg",1024,683,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/45\/2022\/01\/controversial-new-research-on-the-impact-of-salmon-farms-dismissed.jpg",1024,683,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbccountryfile\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"By Andrew Griffiths Published: Wednesday, 05 January 2022 at 12:00 am New research claiming that intensive salmon farming off the west coast of Scotland has no harmful effects on wild salmon populations has been dismissed by a leading conservation organisation as \u201cmanipulating and cherry-picking statistics\u201d. Many fish biologists maintain that farmed salmon have a negative…","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbccountryfile\/wp-json\/wp\/v2\/rss_feed\/259"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbccountryfile\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbccountryfile\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbccountryfile\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbccountryfile\/wp-json\/wp\/v2\/media\/260"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbccountryfile\/wp-json\/wp\/v2\/media?parent=259"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbccountryfile\/wp-json\/wp\/v2\/categories?post=259"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\""Haaf\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/22\/2020\/03\/Solway-salmon-52c06e5-scaled.jpg?quality=45&resize=556,556"\" "\\"\"Haaf\\"\/")
<\/div><\/div> <\/div> <\/section>Criticism of the new research<\/h3>\n
Scottish salmon: a tale of decline<\/h3>\n
The problems with sea lice and farmed salmon<\/h3>\n
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