Case study: Marine non-native species monitoring in the Orkney Islands

Systematic monitoring of marine non-native species in the Orkney Islands was started in 2013 (Figure 1). The monitoring programme is part of the updated Ballast Water Management Policy for Scapa Flow which was adopted by Orkney Islands Council in 2013 and is the responsibility of Orkney Islands Council Harbour Authority (OICHA, 2017). Comparable data from surveys of both artificial habitats and natural sites have been collected each year since 2013. Surveys of 34 sites have been repeated annually (2013-2019) and surveys of 26 sites have been conducted opportunistically over the same period, resulting in 264 individual surveys and in the collection and analysis of 687 samples. The survey methods have ranged from rapid assessment surveys, settlement panels, scrape samples from hard surfaces, benthic grab samples and phyto- and zooplankton tow samples. At each site seawater temperature and salinity measurements were also taken.

 

Figure 1: Annual and one-off NNS survey sites, 2013-2019. © Orkney Harbour Authority
Figure 1: Annual and one-off NNS survey sites, 2013-2019. © Orkney Harbour Authority.

 

The monitoring programme has recorded 19 marine non-native species (NNS) in Orkney (Table 1). The number recorded increased by seven species in 2014 when surveys at Kirkwall, Stromness and Westray marinas were included in the monitoring programme (Figures 2, 3, 4). Marinas are known ‘hot-spots’ for NNS worldwide and the high number of NNS in the three Orkney marinas reflects this (Figure 5).

 

Table 1: Non-native species recorded by monitoring programme in Orkney.
Phylum Species Origin Year of first record in the Orkney Islands
Phaeophyceae Colpomenia peregrina NW Pacific 1960-1987 (Nall et al 2014)
Rhodophyta Asparagopsis armata Australasia 1960-1987 (Nall et al 2014)
Rhodophyta Bonnemaisonia hamifera NW Pacific 1960-1987 (Nall et al 2014)
Rhodophyta Dasysiphonia japonica NW Pacific 2011 (Kakkonen et al 2019)
Rhodophyta Melanothamnus harveyi NW Pacific 2014 (Kakkonen et al 2019)
Chlorophyta Codium fragile subsp. fragile NW Pacific 1891 (Provan et al 2007)
Annelida Boccardia proboscidea NW Pacific 2014 (Kakkonen et al 2019)
Annelida Goniadella gracilis NW Atlantic 2018 (OICHA unpublished)
Arthropoda Caprella mutica NW Pacific 2006 (Ashton 2006)
Diptera Telmatogeton japonicus NW Pacific 2015 (Kakkonen et al 2019)
Mollusca Mya arenaria NW Atlantic 1938 (ICIT 2004)
Mollusca Potamopyrgus antipodarum Australasia 1938 (ICIT 2004)
Bryozoa Fenestrulina delicia Unknown 2018 (OICHA unpublished)
Bryozoa Tricellaria inopinata NW Pacific 2012 (Nall et al 2014)
Bryozoa Bugulina simplex NW Atlantic 2012 (Nall et al 2014)
Bryozoa Schizoporella japonica NW Pacific 2011 (Ryland et al 2014)
Bryozoa Watersipora subatra NW Pacific 2019 (Kakkonen et al 2020 submitted)
Chordata Asterocarpa humilis Southern Ocean 2014 (Kakkonen et al 2019)
Chordata Corella eumyota Southern Ocean 2012 (Nall et al 2014)

 

Number of NNS recorded each year of the monitoring programme with cumulative number of NNS year on year
Figure 2: Number of NNS recorded each year of the monitoring programme with cumulative number of NNS year on year.

 

Total number of non-native species recorded at each survey site (2012 – 2017)

Figure 3: Total number of non-native species recorded at each survey site (2012 – 2017). Modified from Kakkonen et al., 2019.

 

Total number of sites for which each non-native species has been recorded for each sampling method for 2016 and 2017.

Figure 4: Total number of sites for which each non-native species has been recorded for each sampling method for 2016 and 2017.

Abbreviations: Cm: Caprella mutica, Bh: Bonnemaisonia hamifera, Sj: Schizoporella japonica, Ce: Corella eumyota, Cp: Colpomenia peregrina, Cf: Codium fragile ssp. fragile, Ti: Tricellaria inopinata, Ah: Asterocarpa humilis, Mh: Melanothamnus harveyi, Dj: Dasysiphonia japonica, Cs: Ctenodrilus serratus, Tj: Telmatogeton japonicus, Pa: Potamopyrgus antipodarum. Modified from Kakkonen et al., 2019.

 

Schizoporella japonica Kirkwall marina
Codium fragile Stromness marina
Figure 5: Schizoporella japonica at Kirkwall marina (left); Codium fragile ssp. fragile at Stromness marina (right) © Orkney Harbour Authority.

 

In Orkney the most NNS have been recorded on artificial habitats: navigation buoys (sites 7 – 11, 48, 49) (Figure 6, top left), marinas (sites 21, 22, 23) (Figure 6, top right), pier and harbour walls (sites 24 – 30) (Figure 6, bottom left) and Visitor Yacht Mooring buoys and fenders (sites 31 – 47) (Figure 6, bottom right). This highlights that currently, in Orkney, marine NNS are most likely to establish and thrive on man-made artificial habitats rather than in the natural environment.

 

Inspection of a navigation buoy
Westray marina

 

Moaness Pier, Hoy NNS site
Biofouling on yacht fender
Figure 6: Inspection of a navigation buoy (top left); Westray marina (top right); Moaness Pier, Hoy NNS site (bottom left); Biofouling on yacht fender (bottom right) © Orkney Harbour Authority.

 

The programme has used several methods in surveying and collecting samples and this use of different methods has proven an important element of the programme. Data analysed for 2016 and 2017 showed that large conspicuous species, for example Japanese skeleton shrimp Caprella mutica, were recorded during rapid assessment surveys, in scrape samples and by the settlement panels (Figure 7). In comparison the small Jenkin’s spire snail was only recorded in scrape samples. The use of several methods at each site has ensured that as many NNS as was possible were recorded.

 

Settlement panel with temperature logger
Scrape sample for navigation buoy
Figure 7: Settlement panel with temperature logger (left); Scrape sample for navigation buoy (right) © Orkney Harbour Authority.

 

The NNS monitoring programme in Orkney is an on-going programme which continues to record new arrivals and the dispersal of already established NNS within the Orkney Islands. No invasive marine NNS have been recorded in Orkney yet but the on-going programme is ideally placed to detect them if any were to be introduced.

This Assessment page is part of: 

Non-native species (NNS) (sometimes referred to as non-indigenous species) are organisms that are found outwith their natural range as a result of human action. Many coexist with native species with little or no impact, but some can alter the local ecology by smothering and ultimately displacing native species and are referred to as invasive non-native species (INNS). The Non-native species assessment is not based on any established Scotland-wide monitoring programme but rather on incidental reports and some local monitoring programmes. It uses the methods agreed by the Water Framework Directive Technical Advice Group – Alien Species Group. The Case study: Marine non-native species monitoring in the Orkney Islands is an example of a well-established monitoring programme within a single SMR that provides evidence of any spread of NNS within the Region as well as an indication of new arrivals. The Case study: Carpet sea squirt reports on the occurrence and spread of this INNS and the efforts put in place to minimise its impact. It also serves as a good example of the importance to maintain high levels of vigilance and the need for the capacity to be able to respond quickly to such events.

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Image: 
Biofouling © Orkney Harbour Authority
Literature: 
The value of regular monitoring and diverse sampling techniques to assess aquatic non-native species: a case study from Orkney
Rapid assessment of marine non-native species in northern Scotland and a synthesis of existing Scottish records
First occurrence of the non-native bryozoan <i>Schizoporella japonica</i> Ortmann (1890) in Western Europe
Tracking biological invasions in space and time: elucidating the invasive history of the green alga <i>Codium fragile</i> using old DNA
Distribution and dispersal of the non-native caprellid amphipod, <i>Caprella mutica</i> Schurin 1935
Review of biological communities in the Lochs of Stenness and Harray, Orkney
Ballast water management policy for Scapa Flow
Orkney Wildlife Information and Records Centre Mapping Page
Orkney Biodiversity Records Centre

Links and resources