The Underwater Soundscape at Gulf of Riga Marine-Protected Areas

Passive acoustic monitoring (PAM) is widely used as an initial step towards an assessment of environmental status. In the present study, underwater ambient sound recordings from two monitoring locations in marine-protected areas (MPAs) of the Gulf of Riga were analysed. Both locations belong to the natural habitat of pinnipeds whose vocalisations were detected and analysed. An increase of vocal activity during the mating period in the late winter was revealed, including percussive signallings of grey seals. The ambient sound spectra showed that in the current shallow sea conditions ship traffic noise contributed more in the higher frequency bands. Thus, a 500 Hz one-third octave band was chosen as an indicator frequency band for anthropogenic noise in the monitoring area. It was shown that changes in the soundscape occurring during the freezing period create favourable conditions for ship noise propagation at larger distances. Based on the monitoring data, the environmental risks related to the anthropogenic sound around the monitoring sites were considered as low. However, further analysis showed that for a small percentage of time the ship traffic can cause auditory masking for the ringed seals.

Download Full-text

Oceanographic connectivity among marine protected areas on the north coast of British Columbia, Canada

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-088 ◽

2005 ◽

Vol 62 (6) ◽

pp. 1350-1362 ◽

Cited By ~ 12

Author(s):

Clifford LK Robinson ◽

John Morrison ◽

Michael GG Foreman

Keyword(s):

British Columbia ◽

Protected Areas ◽

Marine Protected Areas ◽

Particle Dispersion ◽

Marine Conservation ◽

Ocean Current ◽

North Coast ◽

Late Winter ◽

Conservation Area ◽

The North

The main objective of our study was to use a three-dimensional oceanographic simulation model to understand connectivity among the proposed Gwaii Haanas National Marine Conservation Area (GHNMCA) and 10 other proposed or existing marine protected areas (MPAs) on the north Pacific coast of Canada. The simulations were conducted using passive particles placed at three depths and vertically migrating particles for 30 or 90 days in late winter. Simulated surface particle dispersion was found to be consistent with winter ocean current observations made from analysis of satellite imagery, current mooring, and drifter data. The GHNMCA would contribute to a network of MPAs because it supplies and receives particles from other MPAs in northern British Columbia. Model simulations also indicate that the greatest source of particles to GHNMCA originate from 30-m and not 2-m flows. Finally, the simulated mean daily dispersal rate of 2.0 km·day1 would allow fish and invertebrates to self-seed northern portions of the GHNMCA in winter. Together, the GHNMCA and other MPAs appear to contribute a large percentage of particles to non-MPA regions in northern Hecate Strait, which may be considered a particle sink in winter.

Download Full-text