Name: Audie K. Kilfoyle
The objective of this study was to determine if electromagnetic field (EMF) emissions from undersea power cables impacted local marine life, with an emphasis on coral reef fish. The work was done at the South Florida Ocean Measurement Facility of Naval Surface Warfare Center in Broward County, Florida, which has a range of active undersea detection and data transmission cables. EMF emissions from a selected cable were created during non-destructive visual fish surveys on SCUBA. During surveys, the transmission of either alternating current (AC), direct current (DC), or none (OFF) was randomly initiated by the facility at a specified time. Visual surveys were conducted using standardized transect and point-count methods to acquire reef fish abundances and species richness prior to and immediately after a change in transmission frequency. The divers were also tasked to note the reaction of the reef fish to the immediate change in EMF during a power transition. In general, analysis of the data did not find statistical differences among power states and any variables. However, this may be a Type II error as there are strong indications of a potential difference of a higher abundance of reef fish at the sites when the power was off, and further study is warranted.
US Department of Energy; grant number: DE-EE0006386
South Florida Ocean Measurement Facility (SFOMF) of Naval Surface Warfare Center, offshore Broward County, Florida
- Examine if specific EMF emissions from an offshore cable have any influence (attraction or repulsion) on an in-situ assemblage of routinely monitored coral reef fish;
- Determine if further study is warranted.
In conclusion, much of the literature dealing with EMF effects on marine vertebrates can be summed up as contradictory or inconclusive. This study is in some measures likewise. There are some caveats to consider. We did not see adequate numbers of some species, especially elasmobranchs, known to reside in or transit the area. Thus, some local species might be impacted but our results would not clearly show it. Also, we cannot discount the possibility that the time intervals between power states utilized here (approximately 30 min) to assess changes in reef fish populations was too short to capture slow changes that may be occurring as a result of altering the power state, and the low sample sizes and high count variability may be obscuring some statistical analyses. These caveats notwithstanding, we did not find that the EMF provided at the SFOMF had dramatic impact on the fish assemblage we examined. Nonetheless, although no behavioral effects were noted, the distribution data do provide evidence that the EMF may be eliciting some short-term impact on fish leading to their avoidance of both the AC- and DC-generated EMF. We are reluctant to say this impact is benign. Subtle changes in place preference may result from EMF-induced changes in orientation, anxiety, temperature, etc. The potential long-term effect of such impact, if any, on the distributions of fish populations and community structure is not known, and further research is needed. Additional studies involving larger sample sizes, longer time intervals with the power remaining constant for each particular current type (OFF vs. AC vs. DC), different power strengths, and sites are required. Because the potential sensitivity of most non-elasmobranch fish to EMFs appears low, combining such field studies in conjunction with laboratory behavioral studies would likely produce more conclusive results.
Kilfoyle AK, Jermain RF, Dhanak MR, Huston JP, Spieler RE (2018). Effects of EMF emissions from undersea electric cables on coral reef fish. Bioelectromagnetics. 39:35–52, DOI: 10.1002/bem.22092.