Common HELCOM monitoring of relevance to the indicator is described in the HELCOM Monitoring Manual in the programme topic: Non-indigenous species.
Non-indigenous species are occasionally detected in regular biological monitoring programmes, previously described e.g. in the COMBINE manual. Some national differences in the sampling strategies exist, thus causing some discrepancy in the predicted detection rate of new NIS arrivals. Despite differences between the countries a homogenized strategy for NIS detection should be pursued including also port monitoring.
Guidelines for monitoring of non-indigenous species by extended Rapid Assessment Survey are adopted and published.
The monitoring activities relevant to the indicator that are currently carried out by HELCOM Contracting Parties are described in the HELCOM Monitoring Manual monitoring concepts table.
Prior to 2012 and the HELCOM ALIENS 2 (HELCOM 2013a) and BALSAM projects, only Estonia had monitoring of NIS in the vicinity of the port and there was no monitoring inside the actual port area. Since 2012 Estonia has carried out annual port surveys. Sampling was conducted in ports during the ALIENS projects, but there are no guarantees of the continuation at any interval due to lack of resources. Latvia and Poland have also conducted port surveys since 2013, although not regularly. In addition, some individual port surveys and long-term projects have been conducted in Poland (e.g. Norman-Saremba et al. 2017), Lithuania and Finland (Paavola et al. 2008). As part of these projects, data on the presence of NIS in ports in Estonia (Muuga), Finland (Turku, Naantali, Kotka, Hamina, Sköldvik and Kokkola), Poland (Gdynia) and Sweden (Gothenburg) are currently available on line. In 2009 Germany established an annual "Rapid Assessment Survey" (RAS) to improve monitoring on non-indigenous species in ports in 2009 and extended the sampling referring to the HELCOM/OSPAR protocol in 2016 (eRAS). This method still needs further development since important organism groups such as phytoplankton, jellyfish, and fish are not included in the eRAS method.
Shipping and boating are considered to be primary vectors for the introductions of new NIS into the Baltic Sea. Implementing port surveys regularly in the whole Baltic Sea would greatly increase the confidence of the indicator. One conceivable option for a regular and regionally harmonized monitoring of NIS may be the HELCOM/OSPAR protocol for the execution of port surveys (HELCOM, 2013b). The protocol has been tested in certain Contracting Parties and proposed for inclusion in several national monitoring programmes.
According to the protocol, sampling should be conducted at least twice annually (spring bloom and summer maximum) in minimum every five years to monitor the port areas and also for the purpose of granting ballast water management convention (BWMC) exemptions. During the intermediate period, reviews should take place (not more frequent than annually) based on any new information on the basis of the exemption granted including but not limited to: presence of non-indigenous species, introduction pathways for NIS, changes in physical conditions in the port.
To ensure a good detection rate of new NIS the shallow water habitats should be added to ongoing biological monitoring programmes. In these littoral areas a higher monitoring effort is needed for fish, crustaceans, mussels, snails, macroalgae and plants. Currently NIS data from monitoring is backed up with opportunistic studies and research.