INNS identification information
How to ID INNS?
This page contains information on Japanese Knotweed, North American Signal Crayfish, and Pink Salmon.
The GB Non-Native Species Secretariat (NNSS) website provides identification guides and ID sheets for many INNS, as well as information about their impacts and how to manage them.
Japanese Knotweed
If you have Japanese knotweed on your land, you should ensure it does not spread off your land.
If it spreads into the wild, this is an offence under the Wildlife and Countryside Act (see The law on non-native species section).
You could also be affecting adjacent landowners. Where a non-native species spreads onto a neighbour’s land and causes a nuisance, if it’s not possible to come to an amicable agreement with the neighbouring landowner, then advice from a solicitor on the potential use of civil proceedings would be the next course of action.
The Royal Horticultural Society provides advice for gardeners.
If you carry out any control of this species or undertake any work on areas containing Japanese knotweed, check that you have the correct permissions before starting work (See our Spraying INNS using herbicide and INNS in regulated activities sections).
North American Signal Crayfish
Signal crayfish (Pacifastacus leniusculus) are not widespread in Scotland, so efforts concentrate on preventing them from spreading to protect our uninvaded waters. Once they have been introduced it is very unlikely that Signal crayfish can be eradicated. There have been several trial eradications in small, enclosed waterbodies such as quarry ponds using chemical treatments, but this approach is not possible in larger standing waters or running waters where dilution would be too great and the damage the chemicals would cause to other wildlife would be unacceptable.
Trapping
Although trapping may sound like a useful aid to getting rid of crayfish it can instead make the problem far worse. Traps tend to favour larger male individuals, removing natural predation within the population (the big ones cannibalize the small ones and can help keep the population in check) so leaving a younger, more readily reproducing population that spreads more quickly. Trapping will not control or eradicate a population, and commercial trapping or trapping for personal use is not permitted in Scotland.
The NatureScot licensing team only issue licences for crayfish trapping, or capture by any other method, under exceptional circumstances because the risk of encouraging their spread is so great. They do not issue licenses for the purpose of catching crayfish to eat because in addition to the problems above this also creates incentives for people to move them to new areas.
It is illegal to possess a live crayfish in Scotland. If you witness an illegal activity happening (i.e. the trapping or moving of crayfish), please do not approach the people doing it, but we would encourage you to contact the police by email or by using the non-emergency 101 phone number.
If you catch a signal crayfish accidentally, do not take it away alive. Kill it humanely by placing it on a hard surface, then hit it with a single lethal blow with a heavy or hard object or crush it with a single action.
Preventing spread
You can help prevent the spread of non-native crayfish by following the advice in INNS and biosecurity in water and by reporting any you find (see our How to report an INNS sighting page)
If you need to carry out any work on areas containing North American Signal crayfish, check that you are aware of your responsibilities (see our INNS in regulated activities section).
Pink Salmon
Pacific Pink Salmon (Onchorhynchus gorbuscha) are not native to European waters. They were introduced to some Russian rivers in the 1960’s but slowly spread to colonise some Norwegian rivers.
Occasional sightings of individual vagrant fish have historically been made in Scotland, but in recent years numbers have increased significantly. Increasing numbers are also seen across southern Norway, Ireland and England.
They have a distinct two-year lifecycle, with invading fish being derived from ‘odd’ year stocks, so are currently only recorded in any numbers in odd years, but the increasing quantity of fish arriving threatens our aquatic biodiversity, including native Atlantic Salmon and other fish.
If you see or accidentally catch a Pink Salmon, please report it to Fisheries Management Scotland, where you can also find advice on what action to take.
There is more information on this species on the Scottish Government website.