Bielli, A., Alfaro-Shigueto, J., Doherty, P. D., Godley, B. J., Ortiz, C., Pasara, A., et al. (2019). An illuminating idea to reduce bycatch in the Peruvian small-scale gillnet fishery. Biological Conservation, in press, 108277.
Abstract: Found in the coastal waters of all continents, gillnets are the largest component of small-scale fisheries for many countries. Numerous studies show that these fisheries often have high bycatch rates of threatened marine species such as sea turtles, small cetaceans and seabirds, resulting in possible population declines of these non-target groups. However, few solutions to reduce gillnet bycatch have been developed. Recent bycatch reduction technologies (BRTs) use sensory cues to alert non-target species to the presence of fishing gear. In this study we deployed light emitting diodes (LEDs) – a visual cue – on the floatlines of paired gillnets (control vs illuminated net) during 864 fishing sets on small-scale vessels departing from three Peruvian ports between 2015 and 2018. Bycatch probability per set for sea turtles, cetaceans and seabirds as well as catch per unit effort (CPUE) of target species were analysed for illuminated and control nets using a generalised linear mixed-effects model (GLMM). For illuminated nets, bycatch probability per set was reduced by up to 74.4 % for sea turtles and 70.8 % for small cetaceans in comparison to non-illuminated, control nets. For seabirds, nominal BPUEs decreased by 84.0 % in the presence of LEDs. Target species CPUE was not negatively affected by the presence of LEDs. This study highlights the efficacy of net illumination as a multi-taxa BRT for small-scale gillnet fisheries in Peru. These results are promising given the global ubiquity of small-scale net fisheries, the relatively low cost of LEDs and the current lack of alternate solutions to bycatch.
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Perkin, E. K., Hölker, F., Richardson, J. S., Sadler, J. P., Wolter, C., & Tockner, K. (2011). The influence of artificial light on stream and riparian ecosystems: questions, challenges, and perspectives. Ecosphere, 2(11), art122.
Abstract: Artificial light at night is gaining attention for its potential to alter ecosystems. Although terrestrial ecologists have observed that artificial light at night may disrupt migrations, feeding, and other important ecological functions, we know comparatively little about the role artificial light might play in disrupting freshwater and riparian ecosystems. We identify and discuss four future research domains that artificial light may influence in freshwater and associated terrestrial ecosystems, with an emphasis on running waters: (1) dispersal, (2) population genetics and evolution, (3) ecosystem functioning, and (4) potential interactions with other stressors. We suggest that future experimental and modeling studies should focus on the effects of different spectral emissions by different light sources on freshwater organisms, the spatial and temporal scale over which artificial light acts, and the magnitude of change in light at night across the landscape relative to the distribution of running and standing waters. Improved knowledge about the effects of artificial light on freshwater ecosystems will inform policy decisions about changes to artificial light spectral emissions and distributions.
Read More: http://www.esajournals.org/doi/abs/10.1890/ES11-00241.1
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Verovnik, R., Fiser, Z., & Zaksek, V. (2015). How to reduce the impact of artificial lighting on moths: a case study on cultural heritage sites in Slovenia. J. for Nature Conservation, 28, 105–111.
Abstract: In an ever more artificially illuminated world, common moth behaviour, flight-to-light, causes declines in their abundance and diversity that can have severe impacts on ecosystems. To test if it is possible to reduce the number of moths attracted to artificially illuminated objects, the original lighting of 15 cultural heritage buildings in Slovenia was substituted with blue or yellow lighting. These three illumination types differed in the amount of luminance, percentage of UV and short-wavelength light which are known to affect flight-to-light of moths. During our three-year field study approximately 20% of all known moth species in Slovenia were recorded. The blue and yellow illumination type attracted up to six times less specimens and up to four times less species compared to the original illumination type. This was true for all detected moths as well as within separate moth groups. This gives our study a high conservation value: usage of alternative, environmentally more acceptable illumination can greatly reduce the number of moths attracted to artificially illuminated objects.
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