Or - "When is it time to wash off the leisure boat hull?"
Barnacles can be a problem for boat owners by decreasing the boat´s speed and increasing the fuel consumption. If the barnacles are washed off while they still are small, the problem is usually avoided. The barnacle project, monitoring the time of the attaching of barnacles in the Baltic Proper, also continues during the summer 2009.
The barnacle is a crustacean, and there are several species occurring all over the world. In the Baltic Proper only one species exists, the bay barnacle (Balanus improvisus). This species probably came to the Baltic in the 19th century attached to arriving boats. This species tolerates low salinities and can be found along the Swedish east coast up to the northern Quark in the Bothnian Bay. It lives attached to stones, bridges, larger algae, mussels and boat bottoms from the water surface down to six metres depth.
The adult barnacles are well protected by a thick shell of calcium. However, their first weeks of life they live as freely swimming larvae before they attach to hard surfaces, such as a boat bottom. In the Baltic Sea this attaching usually occurs once during the summer season. The time for the attaching varies and is, for example, affected by the water temperature. During the years when the investigations have been carried out (2001-2008), the settling of the barnacles have usually occurred from mid July to early August and it lasted for one week up to ten days. In the years 2004 and 2005 the situations were different since the barnacles continued to attach to surfaces during a period of four to six weeks. In the column to the right you can find a list of dates when we in earlier years have sent out the "Time to clean the boat hull" - report. In 2006 information was sent out more than once and in 2007 we first informed the area around Västervik (2007-07-26), and later information was sent out for the entire coast (2007-07-31).
When the barnacles have newly attached and are still small, pleasure boat owners can quite easily wash them off by hand with a brush with stiff bristles or with a high-pressure water machine. If this is done within a couple of weeks after the barnacle has attached, one probably gets rid of most of them for the rest of the season. If the barnacles not are washed off in time, they can be very difficult to remove manually. Their growth on boat bottoms can affect the speed of the boat as well as the fuel consumption. This manual washing method is an alternative to using toxic boat bottom paints. This presupposes that one knows when the barnacles have begun attaching to the boats.
The barnacle project is a co-operation between the Archipelago Foundation (Skärgårdsstiftelsen) and the Information Office for the Baltic Proper at the County Administrative Board of Stockholm, and the Keep Sweden Tidy foundation. The aim of this project is to follow and notify when the barnacles start attaching. The project is supported by boat clubs, supervisors of the Archipelago Foundation and people living in the Swedish archipelago areas. The observers continuously monitor barnacle attachment at a number of control stations. These are situated from the county of Gävleborg in the north, to Skåne (Scania) in the south. When our observers detect barnacles on their control surfaces, this information is reported to the Archipelago Foundation, which informs the Information Office and it in its in turn informs boat organisations, media, other county administrative boards etc. that washing of the boat bottoms can reduce the problems with barnacles.
The map above shows places where observations of barnacle settling are made. For the archipelagos of Stockholm and Uppsala see map below.
The map above shows places in the archipelagos of Stockholm and Uppsala where barnacles settling are studied during summer 2009.
New observers were wanted and have been found!
Earlier the project had few observers in the counties of Östergötland, Gotland, Kalmar and Skåne (Scania). In 2009 the project has received extra financing and from the beginning of May an active search for new observers was carried out primarily in the above mentioned counties. As shown in the maps above we now have a large number of voluntary observers. If there are more volunteers, they are asked to contact the Archipelago Foundation before next season. We hope there is an interest to contribute to an even more dense web of observers in order to cover the coasts much better than before.
This project has already been going on for eight years (since 2001), and the Information Office has been reporting about the barnacle attachment since the start.
When is it time to wash the boat bottom?
This year, on July 29, we sent a message that it was time to wash the boat bottoms in the area of Västervik and around Oxelösund and Stendörren in the archipelago of Södermanland. On August 11 we announced that it was time to wash boats in the archipelagos in the counties of Blekinge and Östergötland. On August 17 we reported that it was time to wash the boats in the counties of Stockholm and Scania. On August 24 we reported that it was time to consider boat bottom wash in the County of Uppsala and the area around the town of Gävle. On the same day we also reported that it was time to wash boats on Gotland, Öland and in the County of Kalmar, including the Västervik area. It is probaly soon time to wash the boat bottoms in the remaining areas but not for the moment. With help from the information from earlier years (see the right hand column) a good guess of suitable time can be obtained (some time in the end of July until the beginning of August). The Information Office sends information via E-mail to media and private people and others when the time is right. You can send us an e-mail informing us about your interest to receive a notification about suitable washing time by using one of the links in the right hand column.
Where can I wash the boat?
For those who want to wash their boat bottom in the area of Östra Svealand there is information about places with boat-washing facilities during the summer 2009 on one of the home pages of Keep Sweden Tidy (in Swedish only). As far as we know there are no boat-washing facilities south of Trosa. Further boat-washes may come. Within the frame of the Swedish government´s efforts to reach a better marine environment there are possibilities to apply for financial support for establishment of new boat-washing facilities through the so called "LOVA" grants.
The project is lead by
Karin Strandfager/Cecilia Wibjörn
The Archipelago Foundation in Stockholm County
