Multi-sensor integration for an assessment of underwater radiated noise from common vessels in San Francisco Bay

Abstract

There is growing evidence that smaller vessels not required to broadcast data via the Automatic Identification System (AIS) contribute significant noise to urbanized coastal areas. The Marine Monitor (M2), a vessel tracking system that integrates AIS data with data collected via marine radar and high-definition camera, was employed to track all vessel types (regardless of AIS data availability) in a region of San Francisco Bay (SFB) where high-speed ferry, recreational, and commercial shipping traffic are common. Using a co-located hydrophone, source levels (SL) associated with 565 unique vessel passages were calculated and resultant cumulative daily sound exposure levels across the study area were modeled. Despite large ships primarily having the highest SLs, ferries and motorized recreational craft contributed noise to the largest area in two frequency bands of interest. The M2 provided data without the need for an on-site observer and enabled a systematic analysis of all relevant vessel types which showed that non-AIS vessels should not be excluded from consideration, especially in a highly urbanized estuary like SFB. This research provides an assessment of underwater radiated noise from all common vessel types in SFB suitable for informing habitat quality and threat evaluation for local cetacean species.

New urban habitat for endangered humpback whales: San Francisco Bay

“…Priority projects include tracking whales and ships in the bay using a shore‐based theodolite and radar system to accurately plot the movements and interactions of whales and vessels. This work could be augmented by the installation of hydrophones providing acoustic data to improve the assessment of ship strike risks and provide background on the soundscape, important for resource management (Cope et al, 2020; Cope et al, 2021; Dransfield et al, 2014). Other research is underway in the adjacent Gulf of the Farallones where a hydrophone was anchored in 2022 capable of identifying humpback whale vocalizations (Baumgartner et al, 2019).…”

Northern Range Expansion of California Coastal Bottlenose Dolphins (Tursiops truncatus)

“…Despite recent habitat restoration that led to dramatically improved water quality (San Francisco Estuary Project, 1992), the bay remains one of the most human-altered major estuaries in the U.S. Intensely developed, it is subject to toxic pollution, anthropogenic underwater noise, and congested vessel traffic (Nichols et al, 1986;Cope et al, 2020Cope et al, , 2021. Effective management depends on accurate information about stock boundaries, structure, abundance, and habitat requirements.…”

“…This article is dedicated to our research partners Izzy Szczepaniak (1950-2021), Greg Campbell (1972), and Tom Norris (1965 for their comradery and friendship as well as key contributions to the investigations of California coastal bottlenose dolphins. Izzy helped build the first photo-identification catalog of bottlenose dolphins for the SF Bay Area upon which this article is based.…”

Tattoo Skin Disease in Cetacea: A Review, with New Cases for the Northeast Pacific

“…On the whole, this epidemiological pattern resembles the one observed in P. spinipinnis net-entangled off Peru (22), but differs from the pattern seen in healthy harbour porpoises from UK waters (6). The reasons for the higher infection prevalence in porpoises in the eastern North Pacific are unknown but may be related to stressors associated with residence in and adjacent to San Francisco, the second busiest shipping and boating harbour on the US west coast, habitats with high levels of contaminants, other human interactions such as with fisheries and inter-species aggression from common bottlenose dolphins [ 35 , 36 , 37 , 38 ]. The higher prevalence in males may reflect their accumulation of immunosuppressive lipophilic contaminants throughout life and the depuration of females through the transfer of their contaminant loads to their calves [ 39 , 40 ].…”