Summary of Reported Whale-Vessel Collisions in Alaskan Waters

Hindawi Publishing Corporation Journal of Marine Biology Volume 2012, Article ID 106282, 18 pages doi:10.1155/2012/106282 Research Article Summary of Reported Whale-Vessel Collisions in Alaskan Waters Janet L. Neilson,1 Christine M. Gabriele,1 Aleria S. Jensen,2 Kaili Jackson,2 and Janice M. Straley3 1 Division of Resource Management, Glacier Bay National Park and Preserve, P.O. Box 140, Gustavus, AK 99826, USA 2 Office of Protected Resources, National Marine Fisheries Service, P.O. Box 21668, Juneau, AK 99802, USA 3 Department of Biology, University of Alaska Southeast Sitka Campus, 1332 Seward Avenue, Sitka, AK 99835, USA Correspondence should be addressed to Janet L. Neilson, janet Received 6 February 2012; Accepted 26 March 2012 Academic Editor: Frances Gulland Copyright © 2012 Janet L. Neilson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Here we summarize 108 reported whale-vessel collisions in Alaska from 1978–2011, of which 25 are known to have resulted in the whale’s death. We found 89 definite and 19 possible/probable strikes based on standard criteria we created for this study. Most strikes involved humpback whales (86%) with six other species documented. Small vessel strikes were most common (<15 m, 60%), but medium (15–79 m, 27%) and large (≥80 m, 13%) vessels also struck whales. Among the 25 mortalities, vessel length was known in seven cases (190–294 m) and vessel speed was known in three cases (12–19 kn). In 36 cases, human injury or property damage resulted from the collision, and at least 15 people were thrown into the water. In 15 cases humpback whales struck anchored or drifting vessels, suggesting the whales did not detect the vessels. Documenting collisions in Alaska will remain challenging due to remoteness and resource limitations. For a better understanding of the factors contributing to lethal collisions, we recommend (1) systematic documentation of collisions, including vessel size and speed; (2) greater efforts to necropsy stranded whales; (3) using experienced teams focused on determining cause of death; (4) using standard criteria for validating collision reports, such as those presented in this paper. 1. Introduction Ship strikes are a source of injury and mortality for whales worldwide but documenting these events and their outcomes is a significant challenge. The rate at which whale-vessel collisions occur, the types of vessels involved, and the extent to which they affect particular populations of whales are largely unknown, especially in remote areas such as Alaska. Accurate documentation of whale-vessel collisions is difficult for several reasons, ranging from cases where vessel operators are unaware that collisions should be reported, or operators who do not report for fear of reprisal, to incomplete data gathering on the details surrounding the collision and difficulties inherent in accurately assessing a free-ranging whale’s condition following a collision. In addition, a large ship may strike a whale and the crew may be unaware that the collision occurred. Determining that a stranded whale died from a collision is especially difficult in Alaska because of the logistical challenges of performing complete necropsies (e.g., [1]) on stranded animals. These challenges include the remote location of most carcasses, frequent inclement weather, large tides, concerns for human safety when bears are present, limited daylight at some times of the year, and a lack of personnel trained in identifying ship strike injuries. An overarching challenge in accurately estimating the rate of ship strikes not only in Alaska, but globally, is that there are no universal, standardized criteria for evaluating eyewitness collision reports or stranded whales to determine which cases represent bona fide collisions and which reports should be rejected due to a lack of certainty. Other investigators have compiled accounts of ship strikes regionally and worldwide using variable criteria, terminology, and types of evidence [2–20]. Informed management of whale stocks relies upon accurate estimates of the rate of serious injuries and mortalities from ship strikes. In the United States, the Marine Mammal Protection Act (MMPA) [21] defines a serious injury as any injury that will likely result in mortality. The 2 National Oceanic and Atmospheric Administration (NOAA) is responsible for marine mammal stock assessment reports for all species of cetaceans and all species of pinnipeds except walrus, including an estimate of the annual humancaused mortality and serious injury of each stock by source (e.g., commercial fishing, ship strike, etc.). Internationally, the International Whaling Commission (IWC) considers the number of mortalities from ship strikes with estimates of fisheries bycatch in developing recommendations for large whale conservation. The need for a standardized quality control system to validate collision reports has been recognized by the IWC Vessel Strike Data Standardization Group (VSDG), which formed in 2005 to examine the issue of ship strikes with cetaceans. Since 2007, the group has been developing a global ship strike database that aims, among other things, to identify the level of uncertainty associated with individual records based on strandings and eyewitness collision accounts [22]. The IWC database classifies collision reports into six categories (definite ship strike, probable ship strike, possible ship strike, not a ship strike, whale initiated collision, and rejected report); however, these categories do not yet have standardized definitions (D. Mattila, pers. comm.). Each report is reviewed by the VSDG, and an incident is only classified as a “definite ship strike” if all members are unanimous. At the individual level, the MMPA contains a general prohibition on the “take” of marine mammals, defined as “to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal.” NOAA regulations implementing the MMPA further describe the term “take” to include “the negligent or intentional operation of an aircraft or vessel, or the doing of any other negligent or intentional act which results in disturbing or molesting a marine mammal” [23]. In 2001, NOAA implemented regulations in Alaska limiting approaches to humpback whales to minimize disturbance that could adversely affect individual animals and to manage the threat to these animals caused by increasing vessel traffic and a growing whale watch industry in Alaska. These regulations prohibit vessels from approaching within 91 m (100 yards) of a humpback whale and require vessels to operate at a “slow, safe speed” near humpback whales [24]. This speed is not specified beyond the definition for “safe speed” in 33 US Code 2006, “every vessel shall at all times proceed at a safe speed so that she c (...truncated)