This report contains the results of the craft census carried out on Loch Lomond during the summer of 1995. The results of this study will be presented in a more complete report scheduled for 1996 which will include a more detailed analysis of indirect measures of craft activity. Consequently only limited analysis and interpretation of the results will be carried out here.
This study had three objectives. The first of these was to continue to monitor the long term changes in craft activity on the loch. The second objective was to assess the potential of indirect methods of craft census for estimating craft activity on the loch. The third objective (to determine the effects of new bye-laws on boating behaviour) has yet to be addressed as the implementation of these bye-laws has been delayed until February 1996.
Executive Summary
This report summarises a series of studies into recreational boating use on Loch Lomond carried out between 1989 and 1994.
1 over the study period, craft density was on average 1.6 times higher in the south than in the north of the loch
2 on a smaller scale, consistent clusters of boat activity were identified in two areas (which includes the 'narrows' & Milarrochy Bay)
3 different classes of craft showed preferential use of different areas of the loch
4 annual peak activity was in July/August, winter activity was very low
5 weekend activity was on average 2.5 times higher than weekday activity but there was no evidence of changes in this pattern over this 6 year study
6 launching activity peaked in late morning and again in early afternoon
7 boating activity was at its highest between 11 am and 4 pm
8 weather had a pronounced effect on boat density
9 weather could be used to quantitatively predict activity but a low r sq. indicates that other factors are also influencing activity patterns.
10 counts of launches at Milarrochy Bay suggest that up to 23% of all craft counted during censuses may be launched at this site
11 of the mobile craft launched on a daily basis, windsurfers, jetskis and speedboats are the most common
12 counts over 6 years show a small but statistically significant increase in total craft use over this time
13 in 1994 counts of craft seen in one day exceeded 500 for the first time
14 the number of summer occupied swing and pontoon moorings rose substantially between 1989 and 1994 (by 26%) this increase was higher in the north of the loch than in the south
15 the use of both speedboats and particularly jetskis rose rapidly between 1989 and 1992 (by 500% in the case of jetskis) but seem to have stabilised at the higher level since then
16 mean sizes and operating speeds of craft using Loch Lomond vary depending on boat type but average lengths of classes of craft varied from 2 to 16 m and mean speeds from 3.6 and 54.4 km/hr
17 a model (the LCI model) that weights different craft types of their environmental impact is presented
18 applying the LCI model to Loch Lomond shows that: I the potential for environmental impact is higher at weekends than during the week ii two local areas of the loch are under considerably more intense pressure than others
19 published and unpublished data are used to estimate the potential effect of boat engine pollution, best current estimates suggest that around 36 T of hydrocarbons (the main group of chemical compounds found in boat engine fuel) entered the waters of Loch Lomond in 1994
20 work carried out under controlled laboratory conditions suggest that 95% of these hydrocarbons evaporate into the atmosphere very quickly but that the constituents that remain are very toxic to aquatic animals
21 these persistent chemicals have been detected in water tested from one of areas previously identified as at risk, at a concentration only 17 times lower than that which results in acute mortality in an aquatic test organism
22 the potential for boat engine pollution of Loch Lomond requires a rapid and thorough investigation