LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT 5.0 POTENTIAL ENVIRONMENTAL EFFECTS AND PLANNING IMPLICATIONS FROM EXPLORATION AND PRODUCTION ACTIVITIES The SEA has focused on potential effects that are associated with exploration and production activities, specifically sounds, drill cuttings, miscellaneous discharges, vessel, traffic, animal attraction and accidental events. Mitigation for potential effects is considered, as are potential cumulative effects. In addition, any planning implications that were noted because of environment descriptions, data constraints and/or environmental effects are also discussed in these sections. 5.1 Sound and Noise Effects Anthropogenic sound sources have been grouped into six categories: shipping; seismic surveying; sonars; explosions; industrial activity; and miscellaneous (NRC 2003a). Effects of underwater sound are based on the Source - Path - Receiver concept. The acoustic energy or sound originates with a source. Sound radiates outward from the source and travels through the water as pressure waves. The sound level decreases with increasing distance from the source. The ability of a marine animal to receive sounds is dependent upon the degree of propagation loss between the source and the receiver the hearing abilities of the animal and the amount of natural ambient or background sound in the surrounding sea (LGL Limited 2005b). Figure 5.1 Source - Path - Receiver Model Wind, thermal sound, precipitation, vessel traffic and biological sources all contribute to ambient sound. Ambient sound is highly variable on oceanic continental shelves and this may result in considerable variability in the range at which marine animals can detect anthropogenic sounds. Sikumiut Environmental Management Ltd. © 2008 August 2008 365 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT Communication can also be affected by sound waves produced during seismic surveys. These sound waves also create forces that may cause physiological damage to organisms’ internal organs. Organisms with compressible structures such as air bladders are particularly at risk (Parry and Gason 2006). There are various potential effects of exposure to sound from seismic and other sources that can be characterized as pathological, physiological or behavioural. One data gap is the lack of noise measurement and modelling in the Labrador Shelf SEA Area. Noise measurements and modeling may be useful in impact assessment and in identifying potential mitigations. The following section will provide an overview of the scientific information on the effects of sound to marine organisms. 5.1.1 Species at Risk The marine mammal species at risk that could occur in the Labrador Shelf SEA Area are listed in Table 4.1. COSEWIC species that are not SARA-listed that could occur in the Labrador Shelf SEA Area are noted in Table 4.2. 5.1.1.1 Marine Fish The effects of anthropogenic sound on fish are described in detail in Section 5.1.2. These effects are considered the same for SARA-listed fish, and include changes in behaviour and physical damage. The differences when dealing with SARA-listed fish are the potential consequences of these effects at population levels. For vulnerable populations, the loss of an individual or behavioural changes resulting in decreased fitness or reproductive success, may be detrimental to the population. Therefore, detailed knowledge of the effects of anthropogenic sound on SARA-listed fish is critical for their management and protection. The studies indicate that behavioural effects of seismic activity on SARA-listed fish may include avoidance behaviour, increased swimming speeds, disruption of reproductive behaviour and alteration of migration routes (McCauley et al. 2000a, 2000b). Noise generated by seismic activity may also cause some species to avoid the zone of influence around the seismic vessel. The direct physical effect of seismic activity on adult and eggs of wolffish will likely be minimal or nonexistent as these life stages are found near the bottom at 100 to 900 m from the surface. The greatest potential for harm is when activity is synchronized with larval hatching periods (Kulka et al. 2007). A recent allowable harm assessment (DFO 2004c) concluded that oil exploration activities were determined to have negligible effects on the ability of both northern and spotted wolffish to survive and recover. Sound from seismic activities would unlikely affect the northern and spotted wolffish. 5.1.1.2 Marine Mammals The effects of anthropogenic sound on marine mammals are described in detail in Section 5.1.3. These effects are considered the same for SARA-listed marine mammals, and include changes in behaviour, hearing loss and physiological damage. What differs when dealing with SARA-listed species are the potential consequences of these effects at the population level. For vulnerable populations, the loss of a single individual, or even changes in its behaviour that result in decreased fitness, may be detrimental to a population. As such, detailed knowledge of the effects of anthropogenic sound on SARA-listed species is critical for their management and protection. Sikumiut Environmental Management Ltd. © 2008 August 2008 366 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT Most studies indicate that changes in behavioural patterns resulting from anthropogenic sound tend to be short term. These changes may include avoidance, deviation from normal migration routes, interruption of feeding, reduced surface intervals, reduced dive duration, and lower numbers of blows (Richardson 1986; Ljungblad et al. 1988; Richardson and Malme 1993, 1995; Richardson et al. 1999; McCauley et al. 2000a, 2000b; Gordon et al. 2004; LGL Limited 2005). Anthropogenic sounds may also result in an animal being displaced from, or being deprived of access to, critical habitats. All of these effects have the potential to reduce the survivorship of an animal and decrease its reproductive output. In addition to behavioral modifications, anthropogenic sounds may cause increased levels of physiological stress that result in an individual becoming immune-compromised or having a reduced reproductive output. Knowledge of how short-term stress response may affect the long-term health of marine mammals is unknown (NRC 2003a) and, as such, makes it a matter of concern (Richardson 1986; Ljungblad et al. 1988; Richardson and Malme 1993 and 1995; RIchardson et al. 1999; McCauley et al. 2000a and 2000b; Gordon et al. 2004; LGL Limited 2005), particularly with respect to the SARA- listed species. NRC (2003a) noted that a decrease in feeding rate for marine mammals might potentially equate to a year’s delay in attaining sexual maturity, a small increase in infant mortality, or a slightly shorter life span that may not be important to an individual but could negatively affect the recovery of a SARA-listed population. The biological implications of signal masking will depend greatly on the function of the signal and the context. In a healthy marine mammal population, the introduction of masking noise might have minimal effect; even if the females’ ability to make a mating choice were diminished, they would still be likely to find a mate. In the case of a severely depleted marine mammal population, the ability of males and females to find each other using acoustic cues could become vital for the well-being of the species (NRC 2003b). Unfortunately, our understanding of the mechanics of signal masking is severely limited, and knowledge of how marine mammals use acoustic cues in the marine environment is even more poorly understood (NRC 2003b). These are important data constraints, particularly in reference to SARA-listed marine mammals. 5.1.1.3 Marine Birds Bird Species at Risk could interact with oil exploration activities, including sound from seismic airguns. Little is known about the impacts of underwater sound on birds. Only two of the five bird Species at Risk in the Labrador Shelf SEA spend time underwater, the Harlequin Duck and Barrow’s Goldeneye. Both are diving ducks, making short dives for underwater crustaceans and mollusks. These species would only be present during moulting time, but during this time could be distressed by underwater noise from seismic guns, affecting their foraging behaviour. This could cause avoidance of areas of oil exploration. Oil exploration activities are unlikely to influence Eskimo Curlew, as it would be migrating through terrestrial environments if it were passing through Labrador (assuming the species still exists). The Ivory Gull is associated with pack ice, so it could be affected by oil exploration activities that influence the formation or persistence of pack ice in the Labrador Shelf SEA like shipping traffic. It could also be disturbed by increased air traffic from helicopters and planes. The Peregrine Falcon would not be directly affected by exploration activities except perhaps avoidance of areas of high traffic or noise. It feeds on birds that use the marine environment like Guillemots, but Sikumiut Environmental Management Ltd. © 2008 August 2008 367 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT does not use the marine environment itself, minimizing the potential for sound transmission or oiling events to affect this species. Generally, sound from seismic activities is anticipated to have little interaction with marine bird Species at Risk. Oil exploration activities may cause avoidance of some areas by marine birds, and increased aircraft and vessel traffic may affect reproductive success. Oiling events,