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Resource Issues: Whale Strikes

The Monterey Bay National Marine Sanctuary (MBNMS) provides rich foraging grounds for whales. Large vessels such as tankers and cargo vessels also transit through the MBNMS between important west coast ports. As a result, whales are subject to vessel strikes. The map below showcases incidences of whale strandings due to ship strikes from 2006 to 2012 identified in the National Marine Fisheries Service Regional Stranding database. These numbers are likely to be underestimates of injury and mortality because not all whale strikes will be reported and some dead whales sink instead of washing ashore. Whales are protected by the Marine Mammal Protection Act, and most of these species are considered endangered under the Endangered Species Act. Further, whales in a national marine sanctuary are also protected under the National Marine Sanctuaries Act.

map showing large whale strandings within california due to possible vessel strike 2006-2019
Large whale strandings from 2006 to 2012 within California due to possible vessel strikes. Data from the National Marine Fisheries Service Regional Stranding database.

How is the Sanctuary currently involved?

  • MBNMS staff are providing feedback for the West Coast Spotter App, a mobile application to input and crowd source data on critically endangered whales. The app will help West Coast Sanctuaries meet resource protection goals and create a nexus for geo-spatial data to implement a Dynamic Management Area Scheme to protect whales from ship strikes. West Coast Spotter App will also improve access to data, streamline data collection efforts, improve quality control, and engage the greater public with increased awareness of spatial and temporal distribution of whales in sanctuary waters.
  • MBNMS staff are working with the West Coast Regional Office to research the issue, coordinate with NMFS and USCG, communicate to the industry and public and identify actions. Actions include gaining a better understanding of whale aggregations in or near vessel traffic lanes and deploying NOAA assets such as aircraft to help monitor for whales and vessels, how strikes can be reduced or avoided, and if there is a need for enforcement actions.
  • MBNMS staff worked with the Naval Postgraduate School to complete a report on the monthly distribution of shipping vessels in 2010 within the Monterey Bay sanctuary.
  • Research staff are working on immediate science needs for critical management issues, including the “Impacts on Whales from Human Uses."
  • We've supported research projects to inform managers about whale ecology. In August 2012, Julia Burrows, a Dr. Nancy Foster Scholar, and collaborators from the MBNMS, Duke University Marine Lab, and Cascadia Research Collective conducted a study aboard the R/V Fulmar to examine the fine scale foraging behavior of humpback whales in Monterey Bay. Researchers developed acoustic maps of prey around a foraging (tagged) whale, tracked whales using VHF telemetry, conducted net tows to ground-truth acoustic data, and conducted CTD casts. They plan to continue the study in summer 2013. Results of this study will give us a better understanding of the detailed underwater foraging movements of humpback whales, which can ultimately yield insight into how their natural behavior may leave them vulnerable to ship strikes and disturbance (Data were collected under a NMFS permit issued to John Calambokidis).

    Tracking results from the whale ecology research are shown in this video which begins with the humpback whale at the surface. The red and blue triangles represent the fluke strokes and their size is proportional to the strength of the stroke (larger red area, stronger fluking). The green bar is the depth scale (in meters) with each notch representing one meter. You can see the depth of the whale by looking at the green box on the lower right corner of the screen. It also shows the seconds since the tag was attached and the time in hours, minutes, seconds. This tag was attached to the whale on 12 August 2012. Two foraging dives are shown on this video, with feeding (lunges) occurring when the whale takes several strong fluke stokes at the bottom of the dives. The whale must then stroke vigorously to return to the surface to breathe. The video ends as the whale ascends from its second dive. This video was made using TrackPlot, a software package created by Colin Ware of the University of New Hampshire.

  • Sean Hastings, Resource Protection Coordinator for Channel Islands National Marine Sanctuary, talks about the ship strike issue and what's being done to reduce ship strikes along the West Coast. Check out the video: The video elaborates on how the U. S. West Coast is a critical feeding destination for endangered whales and how it is also home to busy ports and essential shipping lanes. Where whales and ships overlap, there is an increased risk of ship strikes that can cause serious injury or death to whales.

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Reviewed: April 11, 2024
Web Site Owner: National Ocean Service

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