-
Hi Nicolas, this is an important topics for us UW photographers who are also concerned about the possible impacts of our passion on our subjects.
I think it’s also important that we look at this question as a hierarchy of possible impacts i.e. the impacts of flash photography, the more general impacts of UW photographers on the UW environment, and the impacts of scuba diving on marine life and the marine environment. As UW photographers we might be having an impact (or not) at each of these levels as we go about our dive taking photos.There’s been quite a lot of research interest in testing for the existence of these impacts. There are, however, fewer studies that test for the impacts of flash photography on marine animals. I’ve selected a few studies of each of the levels of impact, and have copied and pasted the conclusions from the paper’s abstract/summary. I’ve got PDF copies of most of these studies if anybody is interested in reading the full paper.
IMPACTS OF UNDERWATER PHOTOGRAPHERS ON SEAHORSES
De Brauwer, M., Gordon, L.M., Shalders, T.C., Saunders, B.J., Archer, M., Harvey, E.S., Collin, S.P., Partridge, J.C. and McIlwain, J.L., 2019. Behavioural and pathomorphological impacts of flash photography on benthic fishes. Scientific Reports, 9(1), p.748.
Our study showed that effects of photographic flashes are negligible and do not have stronger impacts than those caused solely by human presence. Photographic flashes did not cause changes in gross ocular and retinal anatomy of seahorses and did not alter feeding success. Physical manipulation of animals by photographing scuba divers, however, elicited strong stress responses.
Spoto, M., Atzori, A., Dionisio, G., Giannattasio, L., Lazic, T., Louisy, P., Monteiro, N., Pierri, C., Ravisato, M., Rinaldi, A. and Gristina, M., 2026. The impact of diver-induced stress on the ventilation patterns of Mediterranean seahorses: A field-based approach. Marine Environmental Research.
Seahorses (Hippocampus spp.) are among the most popular marine species for wildlife tourism, being highly sought by divers and underwater photographers. Due to their unique morphology and behaviour, seahorses are particularly vulnerable to the visual and acoustic disturbances caused by underwater photographers, who often use flash photography to compensate for the seahorses’ cryptic appearance. The present study utilises Opercular Beat Rate (OBR) as a non-invasive method to evaluate the stress induced by underwater tourism activities on Mediterranean seahorses, specifically the long-snouted Hippocampus guttulatus and the short-snouted H. hippocampus. In-situ experiments were conducted on both species, which are commonly found at dive sites throughout the Mar Piccolo of Taranto (MPT) in Apulia, Italy. The OBR was assessed across all four seasons and in both sexes, under both natural and stress-inducing conditions. The results indicate that stress from underwater photography affects both Mediterranean seahorse species, as evidenced by acute alterations in their ventilation rates. Unlike the behaviour exhibited by other seahorse species, the opercular beat rate of Mediterranean seahorses decreases during periods of stress. In H. guttulatus, this decrease may serve as a defensive mechanism, leading to instances where ventilation rates cease completely, resembling thanatosis.
Giglio, V.J., Ternes, M.L., Kassuga, A.D. and Ferreira, C.E., 2019. Scuba diving and sedentary fish watching: effects of photographer approach on seahorse behavior. Journal of Ecotourism, 18(2), pp.142-151.
We investigated if scuba divers are causing behavioral disruptions on seahorses. Divers using and not using cameras were observed while watching seahorses. We recorded the minimum distance that divers approached, the duration of interaction and physical contacts with seahorses, and the behavioral response of seahorses. Divers using action cameras attached to an extension pole approached the seahorses more closely, causing significantly more behavioral disruptions (escape) and physical contact with them. These repeated behavioral disruptions may negatively impact seahorse habits, such as feeding, reproduction, and resting. To mitigate the potential impacts on seahorses, we recommend the establishment of a minimum approach distance of 36 centimeters, the use of a pre-dive briefing to reinforce low-impact diving techniques, and close supervision by dive leaders to ensure appropriated in-water diver behavior.
OTHER IMPACTS OF UNDERWATER PHOTOGRAPHERS
Ma, A.T., Cheung, L.T., Lui, C.Y., Chow, A.S., Zhang, K., Lam, T.W. and Fok, L., 2024. Beneath the lens: Exploring the impacts of underwater photographers in marine-based tourism. Journal of Outdoor Recreation and Tourism, 47, p.100796.
Findings showed that underwater photographers caused more negative impacts than ordinary scuba divers. Among underwater photographers, individuals more interested in conspicuous and actively moving species have more frequent contact with marine organisms. In contrast, those more interested in cryptic and sedentary species were more likely to cause intentional contact. Underwater photographers with greater commitment also showed more frequent and more intentional connections. Implications were drawn regarding underwater photographers’ behaviors, and relevant suggestions were recommended to address the potential concerns.
Toso, Y., Lucrezi, S. and Cerrano, C., 2022. Conservation or degradation? Assessing the behavior of underwater photographers in Italian Marine Protected Areas. Tourism in Marine Environments, 17(3), pp.127-143.
This study aimed to assess and compare underwater photographers’ and nonphotographers’ knowledge of codes of conduct in MPAs, as well as self-reported and observed compliance with these codes of conduct, and perceptions of the health of the marine environment including dive sites. Through direct observations and questionnaires, 84 divers were studied in three Italian MPAs in the summer of 2021. The difference between underwater photographers and nonphotographers was stark, with the former being more likely to violate MPA rules compared to the latter. There was no difference in knowledge of the effects of their behavior on the marine environment between underwater photographers and nonphotographers. Our results can help provide management considerations to reduce the impacts of underwater photography. Awareness campaigns, predive briefings and the promotion of low-impact underwater photography courses can help to limit unsustainable underwater behaviors among underwater photographers. Effective regulation of underwater photography can increase the carrying capacity of dive sites and have positive environmental and economic effects on MPAs and diving destinations.
GENERAL DIVING-RELATED IMPACTS
Giglio, V.J., Blumstein, D.T., Motta, F.S. and Pereira-Filho, G.H., 2022. Diver presence increases egg predation on a nesting damselfish. Journal of Experimental Marine Biology and Ecology, 549, p.151694.
Scuba diving is a form of ecotourism that has demonstrably negative impacts on benthic sessile organisms through diver-induced mechanical damage, but we know relatively less about the direct and indirect impacts of divers on fishes and the communities they live in. Damselfishes (Pomacentridae) are an ideal model to study to understand the effects of human presence on fish behavior because they are common, often territorial and exclusively demersal egg spawners. We experimentally studied the short-term effect of diver presence on eggguarding behavior of a damselfish, the sergeant major, Abudefduf saxatilis. We found that the mere presence of a scuba diver changed the short-term behavior of sergeant majors during their reproductive phase, which resulted in a 92% increase in the frequency of opportunistic predation on their eggs. Identifying the consequences of this human-driven trophic interaction will allow us to evaluate its ecological importance and, if important, guide management efforts to mitigate human impacts.
Sueiro, M.C., Svagelj, W.S., Novacovsky, G.N., D’Amico, V. and Palacios, M.G., 2025. Assessment of Physiological Responses of Patagonian Reef Fishes to Scuba‐Diving Tourism. Aquatic Conservation: Marine and Freshwater Ecosystems, 35(11), p.e70262.
We assessed immunological and general health indices in two marine reef fish species—the rockfish Sebastes oculatus and the Patagonian grouper Acanthistius patachonicus—exposed to long-term scuba-diving tourism. We compared fish from moderately—and heavily visited reefs to those from control (unvisited) reefs. The idiosyncratic patterns observed provided no evidence consistent with impaired immune function or general health in response to diver presence. These outcomes could indicate that fishes have become habituated to diver presence, that more sensitive individuals have been selectively displaced to undisturbed areas and/or the intensity and nature of scuba-diving practices in our study system are below thresholds that would trigger physiological changes. Beyond the ecological significance, our findings provide valuable insights for the sustainable management of marine wildlife tourism. The absence of a clear physiological response in Patagonian grouper and rockfish suggests that properly managed scuba-diving tourism can be compatible with marine conservation goals.
Sumanapala, D., Dimmock, K. and Wolf, I.D., 2023. A review of ecological impacts from recreational SCUBA diving: Current evidence and future practice. Tourism and Hospitality Research, 23(4), pp.564-577.
The research found that SCUBA diving impacted through diver contact with coral reefs caused breakage, fragmentation and led to disease. 10 coral varieties were identified as impacted including some listed as (critically) endangered or vulnerable by the IUCN. Impacts can be minimized using non-regulatory and regulatory management strategies. We present a novel framework that connects diver characteristics with coral reef impacts and discuss how to apply this framework and guide future studies in this area of SCUBA diving research.