PASSIVE ACOUSTIC MONITORING

The human-induced sources of underwater noise and their potential impacts on marine animals are topics of substantial interest and concern among scientists and the public. Although these concerns have mainly focused on injury and/or behavioral disturbance of whales exposed to short-duration sounds, such as sonars, possible impacts to marine animals exposed to continuous sources, such as commercial shipping, have recently begun to garner more attention.  For more information click Background.

Preliminary assessments of background underwater noise levels within the Stellwagen Bank National Marine Sanctuary (SBNMS) were conducted in the summers of 1996 through 1999.  In addition, preliminary passive acoustic surveys for sound-producing fish were conducted in the sanctuary in 2001 and continued through collaboration with fishermen between 2002 and 2005.  For more information on this research click Ambient Noise, Soniferous Fish.

Following a pilot project in 2004, in 2006, a year-long passive acoustic monitoring project was conducted to characterize the sanctuary’s low frequency “noise budget”. Integration of acoustic data with ship tracking data provided initial estimates of noise contributions from large commercial vessels within the frequencies used by vocally-active marine animals in the sanctuary. For more information on this research click Noise Budgets.

Building on these results, a three-year research project was initiated in 2007 to better understand the acoustic environment experienced by, as well as created by, vocally-active animals in the sanctuary. By combining information on the distributions and behaviors of vocalizing marine animals and the distributions, operational conditions and acoustic signatures of vessels and other human and natural sources of underwater sound, researchers are examining the potential for impacts to sanctuary species, including possible changes in communication capabilities due to background noise levels. For more information on this research click Noise Mapping.

SHIFTING THE BOSTON TRAFFIC SEPARATION SCHEME The SBNMS is heavily used by maritime shipping transiting to and from the port of Boston.

As a result, the sanctuary and surrounding waters are a hot spot for collisions between commercial ships and whales. During 2004-2006, scientists from the SBNMS and NOAA Fisheries (Northeast Science Center) investigated ways to reduce the risk of collisions between endangered whales and commercial ships within the sanctuary. This analysis revealed that the current Traffic Separation Scheme (TSS) through the sanctuary routed shipping over high density whale areas. Analysis further revealed that a small northward shift could move the TSS into low density areas and reduce the risk of vessel collision to North Atlantic right whales by as much as 58% and to all baleen whales by as much as 81%.

SURVEY OF HUMAN ACTIVITIES AND MARINE MAMMALS One of the first steps in determining how to best manage national marine sanctuaries and their resources is monitoring, assessing and understanding changes in and threats to these areas.

In July, 2001, the SBNMS undertook a year-long study to quantify and map the spatial and temporal densities of fixed and mobile gear fishing effort and baleen whale sightings. These data were used to depict the "user geography" of the SBNMS and alert managers to areas where intense co-occurrence might signal potential harm to sanctuary resources. Identifying such areas of concern are a vital first step for initiating mitigation measures, as well as facilitating dialogues and information exchange between interest groups seeking solutions to the problem.

WHALE WATCHING GUIDELINES Voluntary operational guidelines have been established by the whale watching industry in the northeast region of the United States, in cooperation with government agencies and non-profit conservation organizations.

To measure compliance with the speed aspect of the guidelines, the SBNMS places inconspicuous observers onboard thirty-five commercial whale watching trips that occurred in and around the SBNMS. Observations were made from August to October 2003. Compliance was evaluated by creating guideline specified speed zone buffers around the sighted whales and overlaying the with the vessel track and speed data. Results indicated that whale watching vessels often ignored speed zone guidelines and that the degree of non-compliance increased as distance from the whale(s) increased.

COMMERCIAL SHIPPING AND RIGHT WHALE ADVISORY ZONES Ship collision is a major mortality threat to the endangered North Atlantic right whale. To mitigate this threat, NOAA Fisheries initiated the Right Whale Sighting Advisory System (RWSAS) that designates advisory zones around right whale sightings.

Researchers at the SBNMS collaborated with managers at NOAA Fisheries (Northeast Science Center) to analyze data from the US Coast Guard's Universal Shipborne Automatic Identification System (AIS), to quantify and assess the behavior of commercial vessels relative to advisory zones, and to make recommendations as to how the RWSAS can better meet its conservation goals.

MOVEMENT OF ATLANTIC COD Atlantic cod populations in the Gulf of Maine have been exploited commercially for several hundred years, and continue to be heavily exploited today.

The successful conservation and management of cod in the Gulf of Maine, and at the scale of the Stellwagen Bank National Marine Sanctuary (SBNMS) in particular, is highly dependent on this information. Scientists from NOAA, Pfleger Institute of Environmental Research (PIER) and the National Undersea Research Center at the University of Connecticut (NURC-UCONN) are collaborating on a research project that is using acoustic telemetry technology to quantify cod movement over different features of the landscape to inform management of the SBNMS and the greater Gulf of Maine region. The high site fidelity of many cod to individual piled boulder reefs suggests that habitat-specific management measures, such as marine reserves, may offer significant protection to cod within the sanctuary.

SEAFLOOR HABITAT RECOVERY MONITORING PROGRAM The southwest corner of the Western Gulf of Maine Closed Area (WGoMCA), which overlaps the SBNMS for a total of 132 square nautical miles, or 22% of the Sanctuary, presented the opportunity to study seafloor habitat recovery following anthropogenic disturbance by bottom-contact mobile fishing gear (such as trawls and dredges).

The Seafloor Habitat Recovery Monitoring Project (SHRMP) was initiated in April 1998, one week prior to the closure of the WGoMCA, to investigate the recovery rates in the SBNMS following impacts from fishing. In August 2001, several sites along the route of a new fiber optic cable and in adjacent areas were added to the existing SHRMP stations to investigate the recovery of seafloor habitats following the laying of the cable by plow. The SHRMP is a collaborative effort between the SBNMS and scientists at the Pfleger Institute of Environmental Research (PIER), the National Undersea Research Center at the University of Connecticut (NURC-UCONN), the US Geological Survey in Woods Hole, Massachusetts, the University of Maine, and Brown University (Brown participated from 2001-2003), with database management provided by Perot Systems.

LARGE MARINE MAMMAL DATABASE In 2001, NOAA contracted Perot Systems to support the SBNMS in the development of a relational database collecting and integrating data on the distribution of marine mammals in the sanctuary.

To complete this task, Perot partnered with the Provincetown Center for Coastal Studies and the Whale Center of New England, as these organizations have access to over twenty years of marine mammal observations in the Gulf of Maine.The five year contract resulted in a database describing the temporal and spatial distribution of multiple species of marine mammals in the sanctuary, representing over 350,000 individual sightings recorded over a twenty five year period (1979-2004).

HIGH DEFINITION IMAGERY ANALYSIS

Monitoring negative anthropogenic effects on the endangered whales and evaluating current regulations and management strategies is essential in order to reduce potential contributing factors to the survival of populations and species. Since 2002, a systematic research effort involving SBNMS and NOAA Fisheries (Northeast Region) in collaboration with Fuji Film U.S.A. Inc. and the Advanced Imaging and Visualization Laboratory at the Woods Hole Oceanographic Institution has employed high performance digital imaging capabilities with the use of the Fuji Airship as an aerial monitoring platform. This opportunity has allowed for ongoing aerial data collection off coastal waters of the northeastern and southern United States, analysis of whale distribution in and around shipping lanes, and compliance with whale watching guidelines.