E C O L O G Y , T O U R I S M A N D M A N A G E M E N T O F H A R B O U R S E A L S ( P H O C A V I T U L I N A )
Sandra M. Granquist
Ecology, tourism and management of harbour seals (Phoca vitulina)
Sandra M. Granquist
©Sandra M. Granquist, Stockholm University 2016 ISBN print 978-91-7649-565-0
Cover photo by: Pétur Jónsson
Printed in Sweden by Holmbergs, Malmö 2016
Distributor: Department of Zoology, Stockholm University
The thesis is based on the following papers, which are referred to in the text by their Roman numerals:
I. Granquist, S.M. & Hauksson, E. (2016). Seasonal, meteorological, tidal and diurnal effects on haul-out patterns of harbour seals (Phoca vitulina) in Iceland. Polar Biology 1-13.
II. Granquist, S.M. & Hauksson, E. (2016). Diet of harbour seals in a salmon estuary in North-West Iceland. Icelandic Agricultural Sciences 29, 7-19.
III. Granquist, S.M., Esparza-Salas, R., Hauksson, E., Karlsson, O. Ingibjörg G. Jónsdóttir&
Angerbjörn, A. Prey consumption of Harbour seals (Phoca vitulina) in north western Iceland: Comparing DNA metabarcoding and morphological analyses. Manuscript.
IV. Granquist, S.M. & Sigurjónsdóttir, H. (2014). The effect of land based seal watching tourism on the haul-out behaviour of harbour seals (Phoca vitulina) in Iceland. Applied Animal Behaviour Science 156, 85-93.
V. Granquist, S.M., & Nilsson, P.Å. (2016). Who's watching whom?–an interdisciplinary approach to the study of seal-watching tourism in Iceland. Journal of Cleaner Production 111, 471-478.
VI. Marschall, S., Granquist, S.M. & Burns, G.L. Interpretation in Wildlife Tourism: Assessing the effectiveness of signage on visitor behaviour at a seal watching site in Iceland.
Accepted for publication in Journal of Outdoor Recreation and Tourism (2016).
Candidate contributions to thesis papers*
I II III IV V VI
Conceived the study Substantial Substantial Substantial Substantial Substantial Substantial Designed the study Substantial Substantial Substantial Substantial Substantial Substantial Collected the data Substantial Substantial Substantial Significant Substantial Minor Analysed the data Minor Significant Substantial Substantial Substantial Minor Manuscript preparation Substantial Substantial Substantial Substantial Substantial Significant
*Contribution Explanation
Minor - contributed in some way, but contribution was limited Significant - provided a significant contribution to the work
Substantial - took the lead role and performed the majority of the work
Reprints were made with permission of the publisher
Contents
Introduction ... 1
Anthropogenic interactions with wildlife populations ... 1
Pinnipeds and the fishing industry ... 1
Pinnipeds and the tourism industry ... 1
Harbour seals in Iceland ... 2
The triangle relationship ... 4
Aims ... 5
Methods ... 5
Study area ... 5
Haul-out behaviour (Paper I) ... 6
Diet (Paper II & III) ... 7
Tourist interactions with seals (Paper IV - VI) ... 7
Results and discussion ... 9
Haul-out behaviour (Paper I) ... 9
Diet (Paper II & III) ... 10
Tourist interactions with seals (Paper IV-VI) ... 11
General conclusion ... 14
References ... 16
Sammanfattning ... 20
Acknowledgement ... 21
Abstract
In cases where human and wildlife are co-using the same geographical areas and resources, management issues often get complex and stakeholder conflicts are common. The Icelandic harbour seal (Phoca vitulina) population is rapidly decreasing, but direct culling of seals still occurs. At the same time seals are becoming an important resource due to increased interest in wildlife watching. Despite the complicated management situation, the Icelandic harbour seal population is one of the least studied pinniped populations in the world. Mapping the typical haul-out pattern is an important foundation for further studies. In paper I haul-out behaviour of harbour seals was investigated and a seasonal haul-out pattern was detected with the maximum number of seals hauling out during summer. A bimodal distribution curve was found during the summer time, suggesting that pupping period occurs in late May to early June, while moulting occurs in late July to early August. Tidal state, air-temperature and wind-speed affected the haul- out boots. Today, the main reason for culling harbour seals in Iceland is to reduce harbour seal predation on salmonids, despite limited knowledge on the effect of seal predation on salmonid populations and salmon angling. The diet of harbour seals that haul out in the estuary area of Bjargós and Ósar in NW-Iceland was therefore investigated using hard-part (paper II) and DNA metabarcoding analysis (paper III). Both methods showed that the main prey species were sand eels, flatfishes, gadoids, herring and capelin, while salmonids were not an important prey in this area. Based on these results, culling of harbour seals in the area is not likely to have a positive effect on salmonid angling. These results have crucial management implications, especially in the light of the severe decline in the Icelandic harbour seal population. Potential effects of seal watching tourism on the harbour seal population must also be considered in management plans.
In paper IV, we investigated the effects of land based seal watching on seal behaviour and found that spatial distribution and vigilance was affected by tourists. Calm tourists behaviour had less effect, meaning that disturbance could be reduced if tourist behaviour is modified. In paper V, this line of investigation was followed by analysing knowledge transfer from academia to the tourist industry and a model was presented where a synergy effect of working interdisciplinary is hypothesised. Finally, in paper VI, the effect of signage on tourist behaviour was studied.
Empirical testing showed that teleological information is more effective than ontological in terms of modifying general tourist behaviour. In this thesis, I present new knowledge on behaviour and diet of harbour seals, as well as new empirical findings on tourist behaviour in wildlife tourism settings. Further I explore interdisciplinary management approaches for seal watching tourism. The findings presented in this thesis have an important value within academic research in environmental-, life- and social sciences and the knowledge can be applied in several areas of harbour seal management in Iceland and elsewhere.
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Introduction
Anthropogenic interactions with wildlife populations
Ecological interactions between human and wildlife populations are complex. A good understanding of such interactions is a prerequisite to facilitate sustainable management of marine mammal population. Human activity, such as hunting or disturbance of animals in their natural habitat has caused common concern of the status of populations of many marine mammal species.
Pinnipeds and the fishing industry
Discussions about the potential effect of marine mammals on human fish harvest have been going on for centuries. The nature of predator and prey relationships in large ecosystems is complicated and it is hard to pinpoint the exact effects of seal predation on commercial fish stocks. Previous research show that in some cases, seal predation can have considerable effect on fish mortality and stock recovery (Bundy 2001, Bjørge et al. 2002a, Trzcinski et al. 2006, Cook et al. 2015), although predation of the stocks is often of smaller magnitude than commercial fisheries harvest (Carter et al. 2001, Hansen & Harding 2006, Houle et al. 2016). Direct interactions between fisheries and seal populations occur when seals become entangled in fishing gear, which may cause them to drown (e.g. Bjørge et al. 2002b, Ólafsdóttir 2010).
Damaged fishing gear due to seal entanglements leads to additional work and costs for fishing companies. Pinnipeds may also consume fish directly from fishing gear, causing harvest losses for the fisheries (Kauppinen et al. 2005, Westerberg et al. 2008). Culling of seals often occur in the vicinity of commercial fishing areas too reduce the effect seal predation is believed to have on harvest or to allow stock recovery. However, the effects of removing seals on the ecosystem and subsequently the fish populations are poorly known (Thompson et al. 2007, Graham 2015, Paper II-III).
Pinnipeds and the tourism industry
The interest for wildlife watching is growing globally, especially within some sectors such as whale and bird watching (Cordell & Herbert 2002, Hoyt & Hvenegard 2002, Higginbottom 2004a, O´Connor et al. 2009, Newsome & Rodger 2013). Wildlife tourism is often considered an important industry that can enhance the economy, in particular in rural areas (Burns 2004).
Tourism can also have positive effects on wildlife conservation through financial support for wildlife protection, increased research of wildlife species and education of visitors regarding wildlife (Reynolds & Braithwaite 2001, Higginbottom & Tribe 2004).
However, anthropogenic disturbance, for example due to tourism may negatively impact wildlife (Paper IV). Animals can be affected physiologically and for example increase in heart rate (Giese 1998, Carney & Sydeman 1999) and hormonal effects have been observed (Creel et al. 2002, Barja et al. 2007). Disturbance may also lead to behavioural changes in the sense that animals spend more time engaged in behaviour that increases their energy expenditure or less time in essential behaviour such as resting and nursing offspring’s. Another known effect is that animals may be forced to alter their spatial distribution which in many cases also affects the tourism industry negatively (Higham 1998, Christiansen et al. 2010). Several previous studies on how tourism affect pinnipeds show that seals may become more vigilant (e.g. Henry & Hamill 2001), flush into the water or abandon haul-out and/or breeding sites (Newsome & Rodger 2007).
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Further, disturbance during the nursing period may lead to separation between female and pup or cause disrupted suckling, which could ultimately decrease the weaning weight and potentially reduce the survival chances of the pup (Renouf et al. 1983, Kovacs & Innes 1990; Osinga et al.
2012). Research on how land based seal watching affects harbour seals is however lacking in the scientific literature.
Numerous strategies can be employed to reduce visitor disturbance of wildlife. These include restricting visitor numbers, implementing protected areas, providing economic incentives, and interpretation (Higginbottom 2004b). As defined by Moscardo et al., 2004: “Interpretation broadly refers to educational activities used in places like zoos, museums, heritage sites and national parks, to tell visitors about the significance or meaning of what they are experiencing”
(Moscardo et al. 2004, p.231). It is used as a tool to both enhance visitor experience and manage their behaviour (Bramwell & Lane 1993) and thereby reduce their disturbance on wildlife (Ham
& Weiler 2002, Higginbottom 2004b). Interpretation is often conveyed via guides, books, shows, brochures and signs and can lead to visitor engagement with conservation issues (Moscardo et al. 2004).
To develop strategies for sustainable tourism management it is crucial to monitor the behaviour of visitors during wildlife encounters. Commonly, in tourism research the methodology to investigate visitor behaviour is based on self-reported behaviour or intentions obtained by interviews or questionnaires (Orams 1997, Hueneke & Baker 2009, Hughes 2013, Jacobs &
Harms 2014), although intentions of behavioural change do not necessarily result in a change of behaviour (Hughes 2013). Empirical studies on actual behaviour is however scarce. As an example, empirical studies thoroughly investigating how providing interpretative information changes visitor behaviour in non-captive wildlife tourism settings are lacking (paper VI).
Harbour seals in Iceland
The Icelandic harbour seal (Phoca vitulina) population has been monitored regularly since 1980 with aerial censuses. The first survey revealed a population estimate of 33.000 harbour seals (Granquist & Hauksson 2016). Since then, there has been a steady decrease in the population size. In 2011, the population size was estimated to be 11.500 seals (Figure 1). A partial census carried out in 2014 indicated a severe decrease (Granquist et al. 2015) and preliminary results from the latest census carried out in 2016 confirms that the population has declined around 40% between 2011 and 2016 (Thorbjörnsson et al. in prep 2016). The reason for the decline is largely unknown, but by-catch of harbour seals in lumpsucker and cod gillnets, along with sealing, are factors that are likely to have affected the decline. According to Icelandic legislation, seals caught as by-catch in fishing gear should be reported to the authorities. However due to insufficient reporting (Ólafsdóttir 2010) it is hard to estimate the total number of by-caught animals, but in 2013, the number of by-caught harbour seals was estimated to 705 individuals (Pálsson et al. 2015). Pálsson et al. (2015) found that harbour seals were the most common by- caught marine mammal species in lumpsucker (Cyclopterus lumpus) fisheries (40.6% of by- caught marine mammals) and the second most common marine mammal (21.0%) to be by- caught in cod (Gadus morhua) gill net fishery.
Contradictory to by-catch, there is no mandatory reporting system regarding sealing and data on sealing in Iceland is unreliable (Granquist & Hauksson 2016). In previous days, seal hunting was an important resource for Icelandic farmers for centuries. Between 1962 and 1975 the annual
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catch was still between 4.500 and 6.000 animals. In the seventies, the utilization of seal products decreased and fewer seals were hunted. Seal meat became less important for human consumption and due to global anti-sealing campaigns, prizes of seal skin collapsed. However, between 1982 and 1989 a bounty system for harbour seals was funded and sealing increased temporary. For the last 20 years harbour seal catches have been relatively small and the main purpose for sealing is no longer the traditional utilization of meat and other product. Today the main reason for hunting is to cull seals around estuaries with the purpose to reduce seal predation on migrating salmonids. In 2015, 159 harbour seals were hunted in total in Iceland and 82% of them were killed around river mouths where salmon rod fishing is conducted (Granquist & Hauksson 2016). Notably, the importance of salmonids in the diet of harbour seals in Iceland and the effect of seal predation on human salmonid harvest has not been investigated (Paper II-III). Previous findings in the scientific literature from other areas of the world suggests that in some areas salmonids are important in the diet of harbour seals that haul out in salmon river estuary areas, while other studies suggest that there are other reasons for seal aggregations in such areas (Wright et al. 2007, Matejusová 2008). Hence, the potential effects of harbour seal removals in estuary areas are largely unknown and might differ between localities.
In Iceland, tourism is currently exploding and the number of visitors travelling to Iceland has increased from a little less than half a million in 2010 to 1.3 million in 2015 (Figure 2). Nature based tourism is the most common reason for foreign visitors to travel to Iceland and around one third of the visitors engage in whale watching (Icelandic tourist board 2016). The increase in the interest for seal watching has led to the development of sites where seals can be watched from land along with activities such as boat based seal watching (Paper IV). Seal related tourism has resulted in economic importance for tour operators and for the general economy in rural areas. Hence, harbour seals are considered as a resource by many anew. However, the seal watching industry depends on seal availability and despite the known effects that tourism related disturbance may have on pinniped populations, regulatory frameworks based on research are often lacking (Curtin et al. 2009, Kirkwood et al. 2003). This is also the case in Iceland, although a code of conduct created for operators and individual tourists has recently been published, with the aim to reduce negative impact on wildlife (The Icelandic Seal Center 2014).
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Figure 1: Estimated population sizes from aerial surveys of Icelandic harbour seals.
Solid lines with blue dots show the mean and dotted lines show the upper (95%) and lower (5%) limit of the confidence limit the lower CI (Granquist & Hauksson 2016).
Figure 2: Total number of visitors travelling to Iceland every year (Icelandic tourist board 2016).
The triangle relationship
To facilitate evidence based management of harbour seals in Iceland, it is of great importance to study interactions between factors that co-dependently affect the harbour seal population. The current situation in Iceland with a severe decline in the harbour seal population, along with booming wildlife tourism interest and limited hunting management (Granquist & Hauksson 2016), underlines that sustainable management is important. The management of harbour seal populations, fisheries and tourism industry interrelate to each other in various ways and can be viewed as a triangle relationship (Figure 3). All these factors have to be considered when aiming for a sustainable management.
Although interactions between the marine fishing industry and harbour seals in Iceland are frequent, the main focus of the fisheries aspect in the triangle will be salmon angling (Paper II- III). It is of immediate importance to investigate predator-prey relationships between harbour seals and salmonid species, and ultimately gain knowledge on interactions between the seal population and the angling industry.
Since potential effects due to tourism on pinnipeds is previously documented in scientific literature (Kovacs & Innes 1990, Henry & Hamill 2001, Newsome & Rodger 2007, Osinga et al.
2012), the booming tourism and the concurring decrease in the harbour seal population facilitates an interesting scenario and underlines that parallel research on different factors is crucial and substrate for management implications (Paper IV-VI). It is important to pinpoint potential effects on harbour seal colonies (Paper IV) and to study possibilities of reducing negative effects due to tourism theoretically and empirically and suggest feasible methods for managing seal watching tourism in a sustainable way (Paper V-VI).
0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000
1980 1985 1989 1990 1992 1995 1998 2003 2006 2011
Mean 95% limit 5% limit
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2010 2011 2012 2013 2014 2015
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Figure 3: The triangle relationship regarding harbour seal management in Iceland. The three stakeholders (the fishing industry, the tourism industry and the seal population) are all aligned.
Aims
The general aim of this thesis was to add to the present knowledge on the ecology and behaviour of harbour seals, as well as gaining knowledge on human interactions with seals, which could facilitate sustainable management of harbour seal populations.
In paper I, factors that affect harbour seal haul-out behaviour was investigated as well as annual haul-out patterns, which is an important foundation for the following studies. In paper II and paper III, hard-part and prey DNA metabarcoding analysis was used to investigate the diet of harbour seals hauling out in an estuary area, in particular regarding the importance of salmonids in the diet. Paper IV investigated effects of land based seal watching on behaviour and spatial haul-out patterns of harbour seals. In addition, tourist behaviour during seal watching was investigated. In paper V, we investigated management strategies for tourist-pinniped interactions theoretically and put forward a model on how to implement knowledge transfer between different academic disciplines and the society. In paper VI the aim was to test if educational signage can change the behaviour of tourists on a seal watching site. We also tested a hypothesis that is put forward in paper V stating that the type of information that is presented to tourists (ontological or teleological information) affects the degree to which tourist behaviour is modified.
Methods
Study area
All papers include research on harbour seals on Vatnsnes peninsula in NW Iceland. Vatnsnes peninsula is one of the areas in Iceland with the highest density of harbour seals (Hauksson 2010). Tourism has increased severely in the area recently and land based seal watching is being developed at several locations on the peninsula (Granquist & Nilsson 2013) and it is also possible to watch seals by boat in the area. The estuary Bjargaós is the inlet for three major salmon rivers; Viðidalsá, Fitjá and Gljúfurá where Atlantic salmon (Salmo salar), Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) are abundant. The Ósar estuary, which is Sigriðarstaðavatn lagoon’s outlet to the sea, is located approximately 1.5 km west of Bjargaós.
Tourism Fisheries
Seal populations
Management
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Close to the estuary area harbour seal pups have been hunted in nets or shot for several years previous to the study to protect salmon fishing interests, although not between 2008 and 2010 due to the studies presented in this thesis. In 2011, however, several pups were shot in the estuary (Figure 4).
Figure 4: Location of Vatnsnes peninsula, North western Iceland. The different study sites in the papers presented in this thesis are indicated with numbers (1= Svalbard, 2= Naggur, 3= Illugastaðir, 4= Hindisvík, 5= Krossanes, 6= Ósar, 7= Bjargaós).
Haul-out behaviour (Paper I)
In paper I, harbour seal abundance was monitored in seven breeding- and haul-out sites on Vatnsnes penninsula; Svalbard, Naggur, Illugastaðir, Hindisvik, Krossanes, Ósar and Bjargaós (Figure 4). To investigate effects of season, tidal states and meteorological factors on haul-out behaviour, harbour seals were counted in the seven haul-out sites during low tide (± 2.5 hours) of every spring tide between January and November throughout the years 2008-2011. During the summer months, more frequent observations were made, or three times a week, at various tidal states for comparison. Diurnal patterns in harbour seal haul-out behaviour was investigated further at Illugastaðir, where seals were counted with 15 minute intervals for 2 h observation sessions twice every observation day between June and August in 2008-2011 (113 days in total).
The relationship between the number of hauling out seals and possible explanatory variables was analysed with generalised linear models (GLMs), generalised additive modelling (GAM) and generalised linear mixed modelling (GLMM) and generalised additive mixed modelling (GAMM)
Arctic circle
ICELAND GREENLAND
VATNSNES PENINSULA
Bjargaós Ósar Hindisvík
Krossanes
Svalbarð Naggur Illugastaðir
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in cases where correlations between the observations were found (Zuur et al. 2009). At Illugastaðir, where several daily data points were available, diurnal effects on haul-out behaviour were investigated by plotting haul-out data in relation to hours from low tide (TLW) using a locally weighted regression procedure for fitting a regression curve by smoothing the dependent variable (TLW) as a function of harbour seal counts.
Diet (Paper II & III)
The diet of harbour seals hauling out in the Bjargaós and Ósar estuary areas was investigated using hardpart analysis (morphological analysis of otoliths and bones), and prey-DNA metabarcoding analysis from faeces samples (Figure 4). Faeces samples were collected during low tide at every spring tide. A total of 253 seal faeces samples were collected (n2009=42, n2010=86 and n2011=125).
Prior to analysis, samples were dissolved in warm water and a subsample was taken for the prey-DNA analysis. The remaining sample was then washed through a sieve with 250 µm mesh size and otoliths, fish bones and invertebrate rests were collected for the hard-part analyses.
In paper II, otoliths formed the basis for the diet analyses, but fish bones and invertebrates were used for secondary information in 2010 and 2011. Hard-parts were analysed by four aspects:
1)Frequency of occurrence of each prey species expressed as the proportion of analysed samples that contained the prey species, 2) Numerical occurrence of individuals of each prey species for all faeces samples in total, 3) Reconstructed weight values of prey species expressed as proportions of weight, and 4) Proportional energy content of the different prey species calculated from reconstructed weight and the appropriate energy density factor (Windell 1971, Ólafsdóttir & Hauksson 2005). Degradation of otoliths was defined on a scale between 1 and 4 depending on morphological features and grade-specific digestion coefficients (de) were used to correct for digestion (Grellier & Hammond 2006). Otolith size was then back-calculated into fish length and fish weight (Härkönen 1986, Hauksson & Bogason 1997). Frequency of occurrence and numerical occurrence of prey species were tested in relation to sampling months and years, using Pearson’s χ2 test of independence with Yate’s correction.
In paper III, prey-DNA barcoding analysis was used to investigate harbour seal diet (n=116).
Further, we compare results from the metabarcoding analysis to results from morphological analysis (n=72). Fish species availability in the study area in 2010 and 2011 was investigated using data collected on a standardized shrimp survey in Húnaflói. The importance of different fish species was investigated in two ways; 1) the frequency of occurrence (see above) and 2) the relative contribution of each species in the harbour seal diet based on the proportion of sequences of each species in the samples. Differences in frequency of occurrence between the two sampling years and between methods were investigated by Fishers exact test.
Tourist interactions with seals (Paper IV - VI)
In paper IV, the effect of land-based tourism on haul-out behaviour of harbour seals was investigated and in paper V and VI, the findings from paper IV were used to investigate potential management implications of seal tourism theoretically and empirically. The study site for papers IV-VI was Illugastaðir seal watching site. Visitors have access to the site throughout the year,
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except during the eider duck (Somateria mollissima) nesting period in the middle of May to the middle of June. The harbour seal haul-out site is located on two skerries, approximately 100 and 200 metres from land. Visitor numbers to the site peak from late June to the middle of August, matching the peak of visitor numbers to Iceland in general (Icelandic Tourist Board 2016).
In paper IV, observations were made with 15 minutes intervals in 2 h observation sessions between June and August of 2008–2010 (466 h in total). In 2008-2010 the spatial distribution of seal was recorded and in 2009-2010 the haul-out behaviour of the seals was in addition recorded (vigilance, flush response, resting, locomotion, nursing and interactions between individuals). The summer was divided into three periods: Pupping/suckling period (1st–20th of June), Weaning period (21st–30th of June) and Post-weaning period (1st of July–31st of August).
Tourists did not have access to the area during the pupping/suckling period, since it coincided with the eider duck nesting, providing us with the possibility to compare different periods with regards of tourist impact on the seals. The number of tourists at the seal watching site was recorded for every observation throughout the study. Additionally, in 2010 group combinations of tourists (single tourist, couple, family and other tourist groups) and tourist behaviour (movement speed, voice level and hand movements) was recorded (122 h in total). A multiple logistic regression was used to investigate the relationship between the proportion of vigilant seals and possible prediction variables (period, number of tourists, seal group size, precipitation and wind chill). A linear regression was used to test if the proportion of seals hauling out on the skerry closest to land decreased with increasing number of tourists. Interactions between tourist behaviour, zone (approaching zone vs. seal watching zone) and tourist group type was tested with a log-linear likelihood test.
In paper V, we investigated what the different academic disciplines; biology and tourism research, may add to an interdisciplinary management approach and explained how a synergetic gain of integrating knowledge from these disciplines may occur. We exemplified how this can be achieved by reviewing and combining results from Paper IV with results from a published report on perceptions and attitudes regarding wildlife watching among tourists visiting Illugastaðir seal watching site (Nilsson 2012). Hence, the first study had its origin in wildlife ecology and the second in tourism research. Further, we investigated theoretically how improved transferal of interdisciplinary research findings from academia to industry increases knowledge of tourists and tourism operators, which in turn has the potential to modify their behaviour and hence reduce the disturbance of wild animals. A model for managing sustainable interactions between tourists and wild animals was elaborated.
In paper VI, we tested the effect of behavioural guidelines presented to visitors on signage at Illugastaðir seal watching site 20 July to 3 September 2014. Visitor behaviour was recorded during three different scenarios: 1) an ontological setup where visitors were provided with signs stating the desirable visitor behaviour without explaining the reason for the guidelines (n=882), 2) a teleological setup, where visitors were provided with signs stating the desired behaviours, and also an explanation of the reason for that guideline (n=793) and 3) a control, where visitors were not provided with any signs (n=765). The observed behaviour was divided into two categories: 1) general behaviour was recorded according to a protocol including hand movement, movement speed and voice level; and 2) direct compliance to the guidelines presented on the signs was recorded.
Logistic regression was used to examine if the variables type of sign, gender, group type and age of the visitors affected visitor behaviour. Predictors influencing the general behaviour were
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tested using a cumulative logit model (CLM) and compliance with the signs was analysed with ordinary logistic regression.
Results and discussion
Haul-out behaviour (Paper I)
A seasonal haul-out pattern was detected among the harbour seals with the maximum number of seals hauling out during the summer time. A bimodal haul-out distribution was found during summer with the first peak occurring in late May to early June and the next peak in late July to early August (paper I). This was the case for all haul-out sites except for Bjargós. The first peak is likely to correspond to the pupping period, while the second is likely to correspond to the moulting period since harbour seals are known to spend more time on land during these processes (Hauksson 1993). The number of seals in Bjargaós peaks between the two haul-out peaks at Ósar. This indicate that the seals use Bjargaós as a foraging site between the pupping and moulting period, which both are periods that are costly in terms of energy (Figure 5).
Results from the GLMM and GAMM show that abundance at the haul-out sites increased with rising air temperature and decreased with increased wind speed and rising tides. When investigating diurnal effects at Illugastaðir, the GAM showed that temperature, time to low tide, day of the year and wind direction affected the haul-out behaviour (p<0.001).
The seasonal haul-out pattern and knowledge on factors affecting haul-out behaviour obtained in this study is crucial for planning future censuses and further, the information creates an important foundation for further studies on harbour seal ecology. The findings strengthen the already enforced method used in the aerial census of harbour seals in Iceland to count at ±3 h of low tide and to carry out the census during the moulting period. However notably, the variation in haul-out behaviour found between the sites, despite their close proximity, underlines the need for care when extrapolating results obtained from a few sites to investigate a larger area.
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Figure 5: Ln (abundance) of harbour seals (Phoca vitulina) hauling out each decimal day of the year on the seven sites; data from all years combined. Unbroken lines indicate the trend estimated with a loess smoother.
Diet (Paper II & III)
When investigating the diet of harbour seals in Bjargaós and Ósar area we found that based on frequency of occurrence, the diet consisted mainly of sand eels (Ammodytes), flatfishes (Pleuronectidae), gadoids, herring (Clupea harengus) and capelin (Mallotus villosus). This was the case for both the morphological (hard-part analysis, paper II) and the molecular (Prey DNA metabarcoding analysis, paper III) methods (Figure 6). The proportion of estimated weight contribution in the diet based on the morphological analysis (paper II) showed that flatfish and sand eel were the most important species. Relative diet contribution based on prey DNA analysis (paper III) implied that sand eel, flatfishes, cod and capelin were most important in the diet.
Interestingly, we found no evidence that salmon or trout were important prey species to harbour seal in this area.
Both in paper II and III we found some inter-annual differences in the diet of the seals, and in paper II, a seasonal difference was detected, where sand eel was the most important species in the first part of the summer (May-July) and flatfish in the end of the summer (August and September). In paper III, we compared the harbour seal diet to species availability and found that the diet corresponded relatively well to the fish species abundance in the area.
Although there was an agreement between the morphological and molecular analysis methods regarding important prey species, species detection was higher using molecular compared to morphological analysis. Several species (e.g. mackerel; Scomber scombrus and bullrout;
Myoxocephalus scorpius) found with the molecular analysis was not detected in the
Decimal day of the year
Ln (abundance)
Naggur Osar Svalbard
Bjargaós Hindisvík Illugastadir Krossanes
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morphological analysis of paper III. Furthermore, the molecular analysis indicated a higher frequency of occurrence of flatfishes, gadoids and herring, when compared to the morphological analysis. A high proportion of the samples in the morphological analysis included unidentifiable otoliths (37.5%), which partly could explain this difference. Another reason for the difference between methods can be that when processing large fishes, like adult gadoids, harbour seals may only eat the most nutritious parts of the fish (liver etc.) and leave the head and other less nutritious parts (Orr et al. 2004) in which cases otoliths and bones would not be found in the faeces (Figure 6). The differences between the two analysis methods that we have identified in this paper call for further investigations and development of analysis methods of pinniped diet.
The main reason for culling harbour seals in Iceland is currently to protect salmonid angling (Granquist & Hauksson 2016). The finding that salmonids are not important prey species of the harbour seal colony in the Bjargós and Ósar estuary area is therefore highly important in terms of management implications, especially in the light of the recent severe decline in the Icelandic harbour seal population (Granquist et al. 2011, Granquist et al. 2015, Thorbjörnsson et al. in prep. 2016).
Figure 6: Frequency of occurrence of species found in the faecal samples in total for all samples (2010 and 2011) using molecular analysis in comparison with data from morphological analysis of the same samples (n=72). Data combined for 2010 and 2011 for both methods
Tourist interactions with seals (Paper IV-VI)
In paper IV-VI different levels of interactions between the seal watching industry and harbour seals were studied as indicated by Figure 7.
In paper IV, we showed that land based seal watching affect harbour seals in the sense that seals changed their distribution when many tourists were in the area, and hauled out on a skerry farther away from land to a higher extent (r= -0.361, n=169, p<0.001). The vigilance of the seals
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Ammodytes Pleuronectidae Gadidae Mallotus villosus Clupea harengus Anarhichas lupus Cyclopterus lumpus Sander lucioperca Amblyraja radiata Other Unidentified
Molecular analysis Morphological analysis
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was affected by several variables (logistic regression, p<0.05); Vigilance was higher when tourists were present in the area, group size of seals affected the vigilance since the proportion of vigilant seals decreased as the number of seals on land increased and in 2009 seals were more likely to be vigilant during precipitation. However, we also showed that vigilance was lower during times when tourists behaved in a calm way (χ2-test: χ2= 9.22, p= 0.002), which is important in terms of management. If visitor behaviour can be affected in the direction of calmer behaviour, it is possible to decrease disturbance of seals.
It is important to note that the seals did not leave the site due to disturbance and flush response due to tourist disturbance was seldom observed, indicating that some level of habituation has occurred among the seals. This demonstrates that this specific area is well suited for wildlife watching. The water between the seal colony and the seal watching zone makes up a natural barrier between the seals and the tourists. Further, the topography allows the seals to alter their distribution between the two skerries and move to the outermost skerry during periods with high disturbance.
In paper V, we exemplify how an interdisciplinary approach can facilitate a synergetic effect in a management perspective by combining findings from paper IV and a report by Nilsson (2012), where tourism is investigated from a social science perspective. Nilsson (2012) showed that when tourists were asked to respond to statements regarding their attitude and perceptions about wildlife watching, their answers were sometimes appropriate in terms of ecological aspects, while in other cases no clear trend in the attitudes between different participants was found. The latter finding revealed that tourists did not always have a conscious idea of what type of behaviour was appropriate during wildlife watching. Interestingly, most conformity was found regarding the statement that said “education is the most appropriate way to manage the behaviour of people taking part in recreational activities in a wildlife area” (statement 1, Paper V). This underlines that focus should be on changing the behaviour/attitude of the tourist through education. We hypothesise that this could be obtained by teleological codes of conducts based on co-operation between tourist operators, authorities and results from interdisciplinary research.
By combining results from Nilsson (2012) and Paper IV, it is clear that the following aspects on constructing a code of conduct for the area should be kept in mind:
1. The presence of tourists in the area had an effect on the spatial distribution and the behaviour of the seals. In addition, more active tourist behaviour disturbed the seals more.
Hence, a code explaining why passive behaviour is recommended may keep the disturbance level at a minimum.
2. Since all different types of groups behaved in a more active way in the approaching zone, the code should explain that the seals are likely to notice the tourists before they will spot the seals and hence that their behaviour is likely to affect the seals not only in the seal watching zone, but also in the approaching zone.
3. Tourists are generally unsure about how to behave. The unintended disturbance for example when seeking the attention of the animals, is a problem and should be prevented by the provision of adequate information to the tourists.
4. Families and groups were likely to have the greatest impact on the animals, since a) they were shown to have the most active behaviour both in the approaching zone and in the seal watching zone and b) larger number of tourists increased the level of vigilance among the
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seals. Therefore, the code should preferably be tailored to suit families with children and other tourist groups.
In the model that was developed (Figure 7), we suggest how the use and protection of wildlife can be balanced, by combining knowledge from different academic disciplines. Further, we suggest that improved transfer of interdisciplinary research from academia to industry increases understanding of the wildlife tourism industry and has the potential to change tourist behaviour and hence minimise disturbance of wild animals.
In paper VI, we used the knowledge gained in paper IV and V to design an empirical study on tourist behaviour during wildlife watching. Since the results from paper IV indicated that seal disturbance can be reduced if visitor behaviour is modified, we tested the effect of signage at Illugastaðir seal watching site. The hypothesis put forward in paper V, that teleological information might be more beneficial than ontological information in terms of modifying visitor behaviour was tested. Our findings show that signage can modify visitor behaviour and that the type of information put forward can have an effect. The cumulative logit model showed that the general visitor behaviour was predicted by type of sign and group type (p<0.001). Overall, visitors introduced to signs behaved more passively than the control group and teleological signs were more effective than ontological signs in terms of affecting the general visitor behaviour (Wald-test: χ2 = 20.2, p < 0.001). Although the compliance to signs was overall high, we showed that teleological signs were in some cases also more effective than ontological signs in terms direct compliance to the behavioural guidance that was presented on the signs. An explanation to the background of a behavioural recommendation is therefore suggested.
Both in paper IV and VI, we observed that the type of group to which visitors belong plays an important role in predicting their behaviour and hence, visitor group types should be payed attention to when designing interpretive information. Families with children behave in the most intrusive way and their compliance to the behavioural recommendations was lower than for other groups. Hence families might have a larger impact on the seal colony than other group type. This knowledge should be taken into consideration, for example when signs are designed.
Further research is recommended to gain deeper understanding of the effectiveness of signage, code of conducts and other interpretation tools in modifying visitor behaviour. Research on the background, knowledge and expectations of visitors is especially recommended because these factors are essential to create an effective management strategy to reduce disturbance on wildlife.
The combined results of paper IV-VI show that harbour seals are affected by the presence of tourist, although tourists commonly want to behave appropriately in order to cause the least damage possible. They must be informed not only of the ecological reason for why a behaviour is recommended, but also understand what lies behind such statements. Increased knowledge and understanding could reduce the potential negative impacts of tourism on wildlife and concomitantly improve the tourism experience.
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Figure 7: A schematic description of the model put forward in paper V. The model would optimally result in a better balance between use and protection of wild animals in the context of wildlife tourism.
General conclusion
This thesis provides important new information regarding harbour seal ecology in the coastal habitat of Iceland with focus on the triangle relationship between tourism, fishing industry and harbour seal conservation. The findings presented here have an important value within academic research in environmental-, life- and social sciences and the knowledge can be applied to facilitate sustainable management of harbour seals in Iceland and elsewhere.
In the thesis, the timing of important biological periods for pupping and moulting was revealed along with information on what factors affect haul-out behaviour of harbour seals in Icelandic conditions. This knowledge is crucial for planning of censuses and creates an important foundation for further studies of various kind (Paper I). Further, we showed that salmonids were not an important food source for harbour seals hauling out in an estuary of some of the most important salmon angling rivers in the country (Paper II-III). These findings are determinative in an evidence based management approach, since they suggest that culling of seals in this area is ineffective. In the light of the recent severe decline in the harbour seal population, these results are important in terms of hunting legislation and management.
Prior to this study, profound studies on how land based seal watching affects harbour seals was lacking in the scientific literature. The results presented in this thesis are therefore important additions to general knowledge on pinniped ecology (paper IV). The importance of how
USE OF WILDLIFE
KNOWLEDGE TRANSFERE (TELEOLOGICAL CODE OF CONDUCT) TOURISM
RESEARCH
PROTECTION OF WILDLIFE
ECOLOGY
WILDLIFE
TOURISTS TOUR
OPERATORS
REDUCED DISTURBANCE CONFLICT
SYNERGETIC EFFECT
INCREASED
KNOWLEDGE/EXPERIENCE INCREASED CARRYING CAPACITY
Paper IV
Paper V
Paper VI
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information is presented to visitors during interpretation has often been discussed in the literature. Differences between effects of ontological vs teleological messages has however not been tested empirically prior to the study presented in paper VI and hence our findings that teleological information is in some cases more effective than ontological information are useful for future wildlife watching management. The results obtained from papers IV-VI are valuable for academic research both within nature and social science disciplines and thus give way for continued interdisciplinary research.
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References
Barja, I., Silván, G., Rosellini, S., Pineiro, A., Gonzalez-Gil, A., Camacho, L. & Illera, J.C. (2007).
Stress physiological responses to tourist pressure ina wild population of European pine marten. Journal of steroid biochemistry and molecular biology 104, 136–142.
Bjørge, A., Bekkby, T., Bakkestuen, V. & Framstad, E. (2002a). Interactions between harbour seals, Phoca vitulina, and fisheries in complex coastal waters explored by combined Geographic Information System (GIS) and energetics modelling. ICES Journal of Marine Science: Journal du Conseil 59, 29-42.
Bjørge, A., ØIen, N., Hartvedt, S., Bøthun, G. & Bekkby, T. (2002b). Dispersal and bycatch mortality in gray, Halichoerus grypus, and harbor, Phoca vitulina, seals tagged at the Norwegian coast. Marine Mammal Science 18, 963-976.
Bramwell, B. & Lane, B. (1993). Interpretation and sustainable tourism: The potential and the pitfalls. Journal of Sustainable Tourism 1, 71-80.
Bundy, A. (2001). Fishing on ecosystems: the interplay of fishing and predation in Newfoundland Labrador. Canadian Journal of Fisheries and Aquatic Sciences 58, 1153-1167.
Burns, G.L. (2004). The Host Community and Wildlife Tourism. In Higginbottom, K. (Ed.), Wildlife Tourism: Impacts, management and Planning (pp. 125-144). Gold Coast: Common Ground Publishing, CRC for Sustainable Tourism.
Carney, K.M. & Sydeman, W.J. (1999). A review of human disturbance effects on nesting colonial waterbirds. Waterbirds 22, 68–79.
Carter, T.J., Pierre, G.J., Hislop, J.R.G., Houseman, J.A. & Boyle, P.R. (2001). Predation by seals on salmonids in two Scottish estuaries. Fisheries Management and Ecology 8, 207-225.
Christiansen, F., Lusseau, D., Stensland, E. & Berggren, P. (2010). Effects of tourist boats on the behaviour of Indo-Pacific bottlenose dolphins off the south coast of Zanzibar. Endangered Species Research 11, 91–99.
Cook, R.M., Holmes, S.J. & Fryer, R.J. (2015). Grey seal predation impairs recovery of an over- exploited fish stock. Journal of Applied Ecology 52, 969-979.
Cordell, H.K. & Herbert, N.G. (2002). The popularity of birding is still growing. Birding 34, 54-59.
Creel, S., Fox, J.E., Hardy, A., Sands, J., Garrott, B. & Peterson, R.O. (2002). Snow-mobile activity and glucocorticoid stress responses in wolves and elk. Conservation Biology 16, 809–814.
Curtin, S., Richards, S. & Westcott, S. (2009). Tourism and grey seals in south Devon:
management strategies, voluntary controls and tourists’ perceptions of disturbance.
Current Issues in Tourism 12, 59-81.
Giese, M. (1998). Guidelines for people approaching breeding groups of Adélie penguins (Pygoscelis adeliae). Polar Record 34, 287-292.
Graham, I.M. (2015). Seal conservations and salmon fisheries in North east Scotland. In: Redpath, S.M., Gutierrez, R. J., Wood, K.A. & Yong, J.C (Eds.), Conflicts in Conservation: Navigating Towards Solutions (pp. 61-63). Cambridge: University Press.
Granquist, S.M. & Hauksson, E. (2016). Management and status of harbour seal population in Iceland 2016: Catches, population assessments and current knowledge. (VMST/16024).
Reykjavík: Institute of Freshwater Fisheries.
Granquist, S. & Nilsson, P.Å. (2013). The Wild North: Network Cooperation for Sustainable Tourism in a fragile Marine Environment in the Arctic Region. In Müller, D., Lundmark, L.
& Lemelin, R. (Eds.), New Issues in Polar Tourism (pp. 123-132). Heidelberg: Springer.
17
Granquist, S., Hauksson, E., Árnadóttir, A.B. & Kasper, J. (2011). Landselstalning úr lofti árið 2011.
Framvinda og niðurstöður [Aerial survey of the Icelandic harbour seal population].
(VMST/11051 ). Reykjavík: Institute of Freshwater Fisheries [In Icelandic, English summery]
Granquist, S.M., Hauksson, E. & Stefánsson, T. (2015). Landselatalning árið 2014 -Notkun Cessna yfirþekju flugvélar, þyrilvængju og ómannaðs loftfars (flygildi) við talningu landsela úr lofti [Harbour seal population assessment 2014- An aerial survey using Cessna airplane,
helicopter and drone to count harbour seals]. (VMST/15002). Reykjavík: Institute of Freshwater Fisheries [In Icelandic, English summery].
Grellier, K. & Hammond, P. (2006). Robust digestion and passage rate estimates for hard parts of grey seal (Halichoerus grypus) prey. Canadian Journal of Fisheries and Aquatic Sciences 63, 1982-1998.
Ham, S.H. & Weiler, B. (2002). Interpretation as the centrepiece of sustainable wildlife tourism.
In Harris, R., Griffin, T. & Williams, P. (eds.). Sustainable Tourism: A Global Perspective (pp. 35-44). London: Butterworth-Heinneman.
Hansen, B.J.L. & Harding, K.C. (2006). On the potential impact of harbour seal predation on the cod population in the eastern North Sea. Journal of Sea Research 56, 329-337.
Hauksson, E. (1993) Seasonal pattern of hauling-out of common seals (Phoca vitulina L.) on Vatnsnes, NW-Iceland. Náttúrufræðingurinn 62, 37–41.
Hauksson, E. (2010) Monitoring trends in the abundance of harbour seals (Phoca vitulina) in Icelandic waters. NAMMCO Scientific Publications 8, 227-244.
Hauksson, E. & Bogason, V. (1997). Comparative Feeding of Grey (Halichoerus grypus) and Common Seals (Phoca vitulina) in Coastal Waters of Iceland, with a Note on the Diet of Hooded (Cystophora cristata) and Harp Seals (Phoca groenlandica). Journal of Northwest Atlantic Fishery Science 22, 125-135.
Henry, E. & Hammill, M.O. (2001). Impact of small boats on the hauloutactivity of harbour seals (Phoca vitulina) in Métis Bay, Saint LawrenceEstuary, Québec, Canada. Aquatic Mammals 27, 140–148.
Higginbottom, K. (2004a). Wildlife Tourism: An Introduction. In Higginbottom, K. (Ed.), Wildlife tourism: Impacts, management and planning (pp. 1 - 14). Gold Coast: Common Ground Publishing, CRC for Sustainable Tourism.
Higginbottom, K. (2004b). Managing Impacts of Wildlife Tourism on Wildlife. In Higginbottom, K.
(Ed.), Wildlife tourism: Impacts, management and planning (pp. 211 - 229). Gold Coast:
Common Ground Publishing, CRC for Sustainable Tourism.
Higginbottom, K. & Tribe, A. (2004). Contributions of Wildlife Tourism to Conservation. In Higginbottom, K. (Ed.), Wildlife tourism: Impacts, management and planning (pp. 99–
123). Gold Coast: Common Ground Publishing, CRC for Sustainable Tourism.
Higham, J.E.S. (1998). Tourists and albatrosses: the dynamics of tourism at the Northern Royal Albatross colony, Taiaroa Head, New Zealand. Tourism Management 19, 521-531.
Houle, J.E., Castro, F., Cronin, M.A., Farnsworth, K.D., Gosch, M. & Reid, D.G. (2016). Effects of seal predation on a modelled marine fish community and consequences for a commercial fishery. Journal of Applied Ecology 53, 54-63.
Hoyt, E. & Hvenegaard, G.T. (2002). A review of whale-watching and whaling with applications for the Caribbean. Coastal Management 30, 381-399.
Hueneke, H. & Baker, R. (2009). Tourist behaviour, local values, and interpretation at Uluru: ‘The sacred deed at Australia’s mighty heart’. GeoJournal 74, 477-490.
18
Hughes, K. (2013). Measuring the impact of viewing wildlife: do positive intentions equate to long-term changes in conservation behaviour? Journal of Sustainable Tourism 21, 42-59.
Härkönen, T. (1986). Guide to the otoliths of the bony fishes of the northeast Atlantic. Hellerup, Denmark: Danbiu ApS.
Icelandic Tourist Board (2016). Tourism in Iceland in figures. Retrieved from:
http://www.ferdamalastofa.is/static/files/ferdamalastofa/Frettamyndir/2016/juni/tou rism_-in_iceland_in_figures_may2016.pdf
Jacobs, M.H. & Harms, M. (2014). Influence of interpretation on conservation intentions of whale tourists. Tourism Management 42, 123-131.
Kauppinen, T., Siira, A. & Suuronen, P. (2005). Temporal and regional patterns in seal-induced catch and gear damage in the coastal trap-net fishery in the northern Baltic Sea: effect of netting material on damage. Fisheries Research 73, 99-109.
Kirkwood, R., Boren, L., Shaughnessy, P., Szteren, D., Mawson, P., Huckstadt, L. & Berris, M.
(2003). 13 Pinniped-focused tourism in the Southern Hemisphere: A review of the industry. Books Online 2006, 257-276.
Kovacs, K.M. & Innes, S. (1990). The impact of tourism on harp seals (Phoca groenlandica) in the Gulf of St. Lawrence, Canada. Applied Animal Behaviour Science 26, 15-26.
Matejusová, I., Doig, F., Middlemas, S.J., Mackay, S., Douglas, A., Armstrong, J.D., Cunningham, C.O.
& Snow, M. (2008). Using quantitative real-time PCR to detect salmonid prey in scats of grey Halichoerus grypus and harbour Phoca vitulina seals in Scotland – an experimental and field study. Journal of Applied Ecology 45, 632-640.
Moscardo, G., Woods, B. & Saltzer, R. (2004). The Role of Interpretation in Wildlife Tourism. In Higginbottom, K (Ed.), Wildlife tourism: Impacts, management and planning (pp. 231–
251). Gold Coast: Common Ground Publishing, CRC for Sustainable Tourism.
Newsome, D. & Rodger, K. (2013). Wildlife Tourism. In Holden, A. & Fennell, D., (Eds.), The Routledge Handbook of Tourism and the Environment (pp. 345-358). New York:
Routledge.
Nilsson, P.Å. (2012) Tourist background and local acceptance. A study of tourists in Northern Iceland. Akureyri: Icelandic Tourism Research Centre.
O’Connor, S., Campbell, R., Cortez, H., & Knowles, T. (2009). Whale Watching Worldwide: tourism numbers, expenditures and expanding economic benefits, a special report from the International Fund for Animal Welfare. Yarmouth MA, USA, prepared by Economists at Large, 228.
Ólafsdóttir, D. (2010). Report on monitoring of marine mammal by-catch in Icelandic fisheries, statistics for 2009 and review of previous information. (NAMMCO SC/17/16).
Ólafsdóttir, D. & Hauksson, E. (2005). Energy content of some fish and invertebrate species in Icelandic waters (Fjölrit 115). Reykjavík: Marine Research Institute.
Orams, M.B. (1997). The effectiveness of environmental education: can we turn tourists into"
greenies'? Progress in tourism and hospitality research 3, 295-306.
Orr, A.J., Banks, A.S., Mellman, S., Huber, H.R., DeLong, R.L. & Brown, R.F. (2004). Examination of the foraging habits of Pacific harbor seal (Phoca vitulina richardsi) to describe their use of the Umpqua River, Oregon, and their predation on salmonids. Fishery Bulletin 102, 108-117.
Osinga, N., Nussbaum, S.B., Brakefield, P.M. & de Haes, H.A.U. (2012). Response of common seals (Phoca vitulina) to human disturbances in the Dollard estuary of the Wadden Sea.
Mammalian Biology-Zeitschrift für Säugetierkunde 77, 281-287.
19
Pálsson, Ó.K., Gunnlaugsson, Þ. & Ólafsdóttir, D. (2015). Meðafli sjófugla og sjávarspendýra í fiskveiðum á Íslandsmiðum [By-catch of sea birds and marine mammals in Icelandic fisheries] (Fjölrit 178). Reykjavík: Marine Research Institute.
Renouf, D., Lawson, J. & Gaborko, L. (1983). Attachment between Harbour seal (Phoca vitulina) mothers and pups. Journal of Zoology 199, 179–187.
Reynolds, P.C. & Braithwaite, D. (2001). Towards a conceptual framework for wildlife tourism.
Tourism Management 22, 31-42.
The Icelandic Seal Center (2014). Sustainable Wildlife Tourism: Guidelines and advice for sustainable wildlife tourism in Iceland, Greenland, Faroe Islands and Norway.
Hvammstangi, Iceland: Wild North Project.
Thompson, P.M., Mackey, B., Barton, T.R., Duck, C. & Butler, J.R.A. (2007). Assessing the potential impact of salmon fisheries management on the conservation status of harbour seals (Phoca vitulina) in north-east Scotland. Animal Conservation 10, 48-56.
Thorbjörnsson, J.G., Hauksson, E. & Granquist, S.M. (2016). Aerial census of the Icelandic harbour seal population in 2016. Reykjavík: Marine and Freshwater Research Institute, in prep.
Trzcinski, M.K., Mohn, R. & Bowen, W.D. (2006). Continued decline of an Atlantic cod population:
how important is grey seal predation? Ecological Applications 16, 2276-2292.
Westerberg, H., Lunneryd, S., Fjalling, A. & Wahlberg, M. (2008). Reconciling fisheries activities with the conservation of seals throughout the development of new fishing gear: A case study from the Baltic fishery-grey seal conflict. American Fisheries Society Symposium 49, p. 1281.
Windell, J. (1971). Food analysis and rate of digestion. In Ricker, W. & Ricker, W. (Eds), Methods for assessment of fish production in fresh waters (Second ed.) (pp. 215-226). Oxford:
International Biological Programme by Blackwell Scientific Publ.
Wright, B.E., Riemer, S.D., Brown, R.F., Ougzin, A.M. & Bucklin, K.A. (2007). Assessment of harbor seal predation on adult salmonids in a Pacific Northwest estuary. Ecological Applications 17, 338-351.
Zuur, A., Ieno, E.N., Walker, N., Saveliev, A.A. & Smith, G.M. (2009) Mixed effects models and extensions in ecology with R. New York: Springer.
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Sammanfattning
Människor påverkar ekosystem på många olika sätt. I de fall där människor och djur nyttjar samma geografiska områden och resurser är förvaltning ofta komplex och konflikter mellan olika intressenter är vanligt förekommande. Då djurpopulationer anses som resurser av vissa parter men av andra är förknippade med förluster blir den generella bilden än mer komplicerad.
I avhandlingen har jag studerat olika typer av antropogena interaktioner med knubbsäl på Island. Knubbsälar är jagade för att minska eventuell påverkan på fiskpopulationer, men knubbsälar har parallellt blivit en viktig resurs i det rurala samhället på grund av ökat intresse för sälturism. Den isländska knubbsälspopulationen har minskat under de senaste årtiondena, och trots att anledningarna inte är fullt kända har jakt och bifångst av säl troligen haft en stor betydelse för minskningen. Dessutom kan turism störa vilda djur på populations eller individnivå, vilket kan leda till fysisk påverkan, beteendeförändringar samt påverkan på spatial utbredning. Islands knubbsälspopulation är trots den komplexa situationen en av de minst studerade sälpopulationerna i världen.
Kartläggning av sälars beteenden på viloplatser är en viktig grundpelare för vidare studier och i artikel I undersöktes haul-out beteende hos knubbsäl på 7 platser vid Vatnsnes på nordvästra Island. Vi identifierade två perioder då sälar ligger uppe på land i högre utsträckning än under resten av året, dvs. i slutet på maj till början på juni då kutarna föds, samt i slutet på juli till början på augusti då pälsbytet sker. Vi fann även att vattenstånd, lufttemperatur och vindhastighet påverkade viloperioderna.
Idag är den vanligaste anledningen till beskattning av knubbsäl på Island att minska den potentiella sälpredationen på lax och öring av sälar som ligger på viloplatser i älvmynningar till viktiga laxfiskeälvar. Detta trots att vetenskapliga belägg för hur och om sälpredation påverkar dessa fiskpopulationer saknas. I artikel II och III undersöktes dieten hos knubbsälar som väljer viloplats vid en viktig laxfiskeälvmynning i området vid Bjargaós och Ósar. I artikel II undersöktes dieten med hjälp av hårddelsanalys av fekalier och i artikel III analyserades bytes- DNA av samma prover med metabarcoding analys och resultaten från de två analysmetoderna jämfördes. Resultaten visar att laxfiskar inte var en viktig del i knubbsälarnas diet i området under studieperioden. De huvudsakliga bytesarterna var tobis, plattfiskar, torskfiskar, sill och lodda. Resultaten är viktiga ur ett förvaltningaperspektiv, exempelvis med anledning av beskattningen i området p.g.a den kraftiga minskningen av den isländska knubbsälspopulationen.
Samtidigt som Islands knubbsälspopulation har minskat kraftigt så ökar intresset för naturturism på Island. Antal turister som besöker Island har ökat ifrån en knapp halv miljon året 2010 till 1.3 miljoner året 2015. Sälskådning byggs nu upp på flertalet platser på Island och man erbjuder både sälskådning från båt och från land. Eftersom det saknas vetenskapliga studier på hur sälskådning från land påverkar knubbsäl, undersöktes detta i artikel IV. Resultaten visade att sälarna ändrade sin utbredning under perioder då många turister besökte sälskådarplatsen och flyttade sig längre ifrån land, samt att sälars vigilans ökade när det var många turister i området. Turisters beteende hade en betydelse, då sälarna var relativt mindre vigilanta när turister hade ett lugnare beteende. Det betyder att störningen som förknippas med turism kan minimeras om turisters beteende kan modifieras. Artikel V bestod därför av en teoretisk studie där möjligheter till kunskapsöverföring från olika akademiska discipliner till individuella turister samt entreprenörer diskuterades. En modell presenterades där ett interdisciplinärt samarbete föreslås ge en synergieffekt ur förvaltningssynpunkt och en hypotes om att
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teleologisk information bör prioriteras framför ontologisk information förklaras teoretiskt. I artikel VI studerades hur implementerandet av en code of conduct (uppförandekod) via skyltning påverkade turisters beteende. Vi visade att teleologisk information i större utsträckning leder till att turister ändrar sitt generella beteende jämfört med ontologisk information. Den interdisciplinära ansatsen i artikel V & VI har resulterat i slutsatser som är viktiga inom både natur- och samhällsvetenskap och lägger grunden till fortsatta interdisciplinära studier inom området.
Som sammanfattning har jag i avhandlingen behadlat ämnen som har en stor betydelse för förvaltning för knubbsäl på Island och i andra områden, och resultaten är viktiga byggstenar för vidare forskning i ekologi samt samhällsvetenskaplig forskning.
Acknowledgement
Thanks to my supervisor Anders Angerbjörn and my co-supervisors Per-Åke Nilsson and Hrefna Sigurjónsdóttir for valuble discussion, especially during the last part of the PhD studies. Thanks also to my follow-up group (Olle Karlsson, Johan Lind and Bodil Elmhagen) for constructive discussions.
Thanks to my former and present co-workers at the Icelandic Seal Center in Hvammstangi, at the Marine and Freshwater Research Institute in Reykjavík and at the Zoological institution at Stockholm University. Helgi Guðjónsson, Hrafnhildur Laufey Hafsteinsdóttir, Ester Sánchez Cacho, Laila Aranda-Romero, Eva Haunss, Elsa Freschet, Halldór Jón Pálsson, Guðmundur Jónsson and Haraldur Friðrik Arason assisted me in the lab and/or by collecting data in the field.
Without your help, this wouldn´t have been possible. Thanks to landowners for allowing us to conduct the research on your property.
Thanks to my friends for being there when I need you; Aldís for endless support in everything I do. Anna, for always believing in me. Helga and Julia thanks for being you. Stina and Lena thanks for making me laugh. Fina and Ásta, you inspire me a lot. Thanks to my family; mom, AnnCharlotte, dad and my siblings Sofia, Robert, Patrik, Josefine, Felicia, Elina and Milliemy.
Thanks to Erna and Bjarki for all the kind help during the most hectic periods, it meant a lot. A big thank you to Halli and to my children Friðrik and Dís (Þið eruð best!).
The projects were supported by NORA (Nordisk Atlantsamarbejde), NATA (North Atlantic Tourism Association), Regional Growth Agreement-North West Iceland, Agricultural Productivity Fund and The Icelandic Student Innovation Fund.
