2.1 Study design

A generic qualitative design (a design not guided by an established set of philosophic assumptions¹⁹), grounded in the pragmatic paradigm was used to guide the study and subsequent methods.²⁰ This study adhered to the Standards for Reporting Qualitative Research (Table S1). A qualitative approach was deemed the most appropriate method because it enabled the interpretation and discovery of experiences^{19, 21} from the perspective of parents to: (a) better understand the facilitators and barriers to accessing and using natural blue spaces, (b) how the quality of these spaces' affects use, and (c) the perceived benefits and risks of spending time in these spaces. Ethical approval was obtained from the Human Research Ethics Committee of the University of Western Australia Human Research Ethics Committee reference number: 2021/ET000722.

2.2 Participants

Purposive and snowball sampling was used to recruit participants who satisfied the study criteria: Participants had to live in one of four coastal community in the Perth Peel (Western Australia) region and have a child between 2 and 10 years of age. It was not a requirement of participation in the study that families needed to visit or use the coast or any blue spaces. The four coastal communities were chosen based on socio-economic status (two residential pockets) of high socio-economic status (SES) and two low SES, derived from the Index of Relative Socio-economic Disadvantage (IRSD).²² The IRSD summarises a range of information on disadvantage (eg, numbers of low income households, unemployment, poor English spoken) at an area level(such as suburb or slightly larger community). The two low SES coastal communities had IRSD scores in deciles ≤3 at a national level indicating relatively high levels of disadvantage. The two high SES coastal communities had IRSD scores in deciles ≥8 at a national level indicating relatively low levels of disadvantage. Geographical location was also considered (two communities north and two south of the Swan River) to ensure a range of blue spaces. Interviews rather than focus groups were conducted to reduce large gatherings in response to the COVID-19 pandemic.

Participants were recruited primarily via social media (Facebook) with geolocation used to specifically target the postcodes across the four coastal pockets. Existing stakeholder networks (Consumer and Community Reference groups and Playgroups) and flyers in local shops were also used.

Participants received participant information, a consent form and a pre-interview demographic and blue space use survey via email. An interview was scheduled at a time and place that was convenient to the participant and researcher and informed consent was obtained, including permission to record the conversation. Of the 32 parents who expressed interest in the study, 25 participated in an interview. Considering the diverse nature of participants' socio-demographic background, the rich and complex stories that emerged, balanced with practical constraints around time, feasibility, and funding²³ this sample size was deemed sufficient.

2.3 Interviews

Research looking at families interactions with blue space⁷ informed the development of an interview guide (Appendix S2) and blue space use survey, which was reviewed by all authors for content validity. A copy of the blue space survey is available from the first author on request. The interviews were semi-structured, allowing discussion and exploration of experiences. Interviews were conducted one-on-one, face to face (n = 7) or via phone (n = 15) or online via Microsoft Teams™ (n = 3) in October and November (Spring) 2021. Where permission was granted interviews were audio-recorded -and transcribed (n = 21), with the remaining four interviews recorded via note taking. Upon completion of the interview, participants were offered $10 (AUD) as a token of appreciation for their time.

At the start of the interviews, the process was explained, that there were no right or wrong answers to questions—just ideas, experiences and opinions and that participants could stop at any time. Participants were asked if they had any questions and if they gave permission to record the interview. At completion of the interview, participants were thanked and invited to ask any questions. Field notes were taken after all interviews for reflexivity. The field notes included how the interviewer felt the interview went, initial thoughts on key themes which arose, any new or contrary themes and any other issues which arose. These notes contributed to the characteristics and reflexivity statement (Appendix S2) and were reviewed during analysis to ensure personal bias did not drive the thematic analysis.

2.4 Data analysis

Descriptive statistics were used to analyse parent-reported socio-demographic factors collected as part of the pre-interview survey. Transcripts were checked to ensure they were coherent before they were imported to NVivo™ where the data was overseen, interrogated, and stored for analysis. Data were analysed using Braun and Clarke's guideline to thematic analysis.²⁴ Data were coded through inductive codes generated from the data as well as informed by concepts represented in the research field.^{20, 24} Initial codes were collated into potential themes that were subject to an ongoing process of review and refinement to best reflect the data and organised into a comprehensive and coherent framework of themes.²⁴ Initially the first author identified potential key themes and subthemes. The second author reviewed the coding and then the thematic summary was agreed upon by both authors. All authors reviewed the framework of themes and provided input around defining and naming themes. When reporting the results, participant quotes were presented to represent the major themes.

3.1 Sample demographics

Most (84%) participants were female, had an undergraduate degree or higher (60%), a third had a trade or TAFE qualification (32%) and 16% had graduated from secondary school or less. Most parents were in a heterosexual relationship (92%), and 8% were not currently in a relationship of any orientation. There were similar numbers of parents residing in high SES (56%) and low SES communities (44%) and 44% of families had a family dog. There were 18 boys aged 10 and under with a mean age of 5.4 years and 27 girls with a mean age of 4.8 years old. There were 13 siblings (9 boys and 4 girls) that were aged 11 years and over.

3.2 Frequency of use and distance to most used blue space

The beach was the most frequently used blue space by families (Table 1), with average use highest in summer (one or more times per week) compared with winter (around once a month). Families lived on average (4.4 km) from their most used beach, with those residing in higher SES coastal communities living closer (3.1 km) than those in lower SES coastal communities (5.6 km). Most families exclusively drove to the beach, and several used a mixture of active transport (ie, walking, riding a bicycle or scooting to the beach) and driving. Rivers were the next most frequently used space by families, followed by the lake, swamp and creek.

3.3 Key themes

Beaches were the most used blue space which participants almost always referred to in the interviews. Four main themes were identified, with several sub-themes (see Figure 1) providing an in-depth understanding of the ways families used blue spaces, particularly the beach and how parents perceived children's health, development and environmental awareness could be impacted by spending time in these places. The themes were “Factors affecting use,” “Environmental awareness,” “Child health,” “Child development.”

4.1 Factors effecting blue space use

The beach was the most used blue space, which is to be expected considering participants were recruited from coastal areas. However, the most proximal beach did not necessarily equate to it being the most used. This was mostly due to the features of different beaches being more or less attractive to families. Parents discussed many modifiable built and natural environment features that effected their beach use. Parking, bike access, showers/toilets, adjacent greenspace, shade, surf-life saving and lifeguard patrols, ramps to the beach, access to cafés and whether the beach permitted dogs all factored into decision making around which beach families chose to their time at. In addition, grassed areas adjacent to the beach, with family-friendly amenities made family beach visits more enjoyable. Given most features within or near blue spaces are modifiable there is a need for local governments to consider family-friendly amenities when planning for community use of blue spaces.

Some parents reported being able to take the family dog with them to the beach influenced which beach they could visit and thus how they got there (drive or active transport). A large proportion of families in the study had at least one dog (44%). U.S. parents report being able to bring the pet to the beach as the third highest priority when visiting the beach.²⁵ An Australian study suggests beaches could offer a safer dog walking experience than suburban parks due to the open space and also that combining personal exercise with the needs of the dogs was a motivating factor for beach use.²⁶ Both of these studies called for access to more dog friendly beaches. In other Australian states such as Victoria²⁶ and South Australia²⁷ dog walking before 9 am and after 7 pm (**excluding those which are national park) is permitted at most beaches (excluding those which are national park). While dog regulations, wildlife protection and conservation of blue spaces should be considered, this option provides a balance between dog-owners (up to 40% of the Australian and U.S. population²⁸) and non-dog owners, allowing both to use the space and benefit.

Overall, more research is needed on the quality (features) of blue spaces especially in relation how this varies by SES and geographical locations. The BlueHealth Environmental Assessment Tool (BEAT)²⁹ was developed to assess the physical, social and aesthetic attributes of blue spaces for the general community. It measures modifiable blue space features including parking, ramps, toilets, shops, lighting, proximal greenspace, presence of lifeguards as well as attractiveness. Future research could test the BEAT for use in capturing blue space access and quality as it relates to child health and development. The findings from the current research suggest items such as parking, measuring proximal greenspace and whether it's a dog friendly beach would be particularly important.

The features of blue spaces also impacted on families' choice to drive or to actively commute (walk or cycle) to the beach. Active transport has many health, wellbeing, and social benefits.³⁰ Furthermore, active transport can have a positive effect on the natural environment, reducing air and noise pollution as well as car emissions.³⁰ Despite living in coastal communities most families drove to the beach. Poor access to public transport and parking fees were barriers to visiting blue spaces. Access to blue spaces could be more equitable for families by ensuring walkable streets and free parking around these areas as well as public transport options.

4.2 Environmental awareness and perceived effects on child health and development

Blue spaces were perceived by parents as opportunities for children to take in the biodiversity of these spaces, potentially prompting environmental awareness and pro-environmental behaviours. Some parents reported how their young children spoke about pollution in relation to the litter they saw at the beach. Eco-anxiety in children is increasing.³¹ Providing children with “constructive hope”, and everyday opportunities to show they can make a difference and may be a way to combat children's eco-anxiety as well as provide planetary health benefits.^{13, 30, 32} Blue spaces could be settings for this through the perceived appreciation, and sense of agency that comes with pro-environmental behaviours when interacting with blue spaces. And while time in natural outdoor spaces broadly is associated with pro-environmentally friendly behaviours,³ our findings suggest more research is needed to investigate components of pro-environmentally friendly behaviours (eg, biodiversity, climate change) attributed to interactions with blue spaces and the mechanisms involved in supporting and developing these behaviours. Future research could investigate whether interaction with blue spaces, is a means of mediating eco-anxiety.

Parents also spoke about the risks that native animals, particularly sharks could pose to their children. It is likely this sub-theme emerged because during data collection, a fatal shark attack occurred in the study region.³³ It is possible this may have influenced parents' perceptions of risk as it received significant media attention. Alarmist shark media coverage has been suggested to influence parental concerns, yet any threat from native animals in natural blue spaces is minimal compared to the risk of drowning at the beach.^{25, 34, 35} During the COVID-19 pandemic drownings in young Australian children increased by 9% compared to the 10-year average and 108% compared to 2019.³⁵ Greater awareness around the actual risks of native animals in blue spaces is needed to balance parents perceived concerns.

Parents perceived benefits and risks to their child's health and development from spending time in blue spaces. While sun exposure was seen as a benefit because of its role in vitamin D production; most parents perceived major risks associated with sun exposure from spending long periods of time outside. Overall, parents awareness of the risks associated sun exposure was high and they were well versed in the prevention of sunburn and other adverse effects of excess sun exposure, which is consistent with the Australian literature.³⁶

Engaging in physical activity and play as a family was overwhelmingly the most dominant perceived health and development benefit discussed. Daily physical activity is crucial for a child's health and development³⁷ with national and international guidelines recommending school-aged children accumulate at least 60 minutes per day of moderate to vigorous intensity physical activity.³⁸ Blue spaces provide a variety of different forms of physical activity and play options for children,⁷ such as surfing, swimming, walking and building sandcastles. The social benefits of interacting with others, particularly as a family, encouraged parents to visit the beach more frequently. Parents also spoke of how blue spaces were not conducive to device (eg, mobile phone) use and without the distraction families enjoyed spending time together, supporting family connection and child development. In support of our findings a survey of U.S. adult beach users found that taking children to the beach was the second highest reason to visit.²⁵ A qualitative study in the UK found the beach to be place where families spent time together.⁷ Combined these findings highlight that the beach can facilitate children's pro-social behaviours.²⁵

Parents shared their perception that blue spaces positively impacted mental health through restoration, via the calming effects of water. Similar findings have been observed in adults whereby blue spaces were reported as calming and positive places for wellbeing.³⁹ In the current study, parents also perceived blue space exposure improved children's sleep and overall behaviour. To date there is little evidence around sleep and blue space exposure, however findings from a recent systematic review on greenspace and sleep showed a positive association between green space use and sleep quality and quantity.⁴⁰ More research is needed to establish objectively whether blue space is associated with sleep in children and the pathways through which this occurs. While parents had varying swimming abilities, they all deemed that it was important children develop a sense of awareness and safety in and around blue spaces. Water safety and awareness is an important component of being able to interact safely with blue spaces. Parents spoke about how natural blue spaces can be a dangerous place for people who cannot swim. This is not surprising as drowning is the second highest cause of death amongst young Australian.¹⁰ Effective evidence-based policy, supervision, education, swimming lessons and water safety are all effective strategies used to reduce the risk of drowning amongst young children.¹⁰

Blue spaces were seen by some parents as places in which children could explore risk taking and develop confidence and resilience. Prior research has shown that nature play in green spaces enhances autonomy, resilience, the development of sense of identity in young children.^37-39 It is generally accepted that the risks and challenges provided by play in natural environments can nurture emotional understanding, a sense of agency and mastery and accomplishment.^{41, 42} Further research is needed to confirm these findings in children and blue spaces.

Development of identity, as community members, and connection to Country and the natural environment was perceived by parents to be supported by spending time in blue spaces. In support of our findings, recent research has explored how children access, interact, and manage in urban blue spaces and highlighted the importance of natural blue spaces for children understand their identity,⁴¹ wellbeing⁷ and how they relate to their environment.⁴¹ Similarly, studies in adults suggest living in proximity to blue spaces promotes shared place making, belonging, attachment to these spaces, as well as social interactions around it, all interrelated and contributing to identity.⁴²

4.3 Limitations

The findings of this study should be interpreted considering several limitations. The nature of thematic analysis means the data interpretation may have been influenced by the researchers' prior experiences and knowledge, however potential bias was avoided through a reflexivity diary. Member checking of the transcripts would have enhanced the validity and trustworthiness of this study. The findings were based on parents' perceptions and recollections. Future research should consider using parents perceptions alongside objective measures of blue spaces (geospatial data). While using blue spaces as a family was not a requirement in participation in the study, the value parents place on blue spaces may have affected whether they participated in the research and thus the views of parents who dislike or fear blue spaces may not have been fully represented. The majority of the respondents were female which may impact the transferability of the findings to other population groups. The collection of other socio-demographic measures (such as work status and ethnicity) could strengthen future studies. Lastly, parents were recruited because they lived in a coastal community. The relationship between blue space and child health and development should also be explored in families who have less access to blue space. Importantly, future research should include the voices of young children.