Ship Strikes Research Articles

Overwintering humpback whales adapt foraging strategies to shallow water environments at the mouth of the Chesapeake Bay, Virginia, USA

AbstractSome humpback whales from the Northwestern Atlantic population forgo migration to the Caribbean, spending winter months feeding along the U.S. mid‐Atlantic coast. We studied the foraging behavior of these whales at the mouth of the Chesapeake Bay, Virginia during winter from 2017 to 2022. While shipping channels here reach depths of up to 30 m, most of the area is 11–15 m deep. This shallow‐water environment poses physical constraints on classical humpback whale feeding modes. We deployed 20 digital acoustic tags (DTAGs) on humpback whales and identified foraging lunges from accelerometer data, detecting 788 lunges from 10 animals. Tagged whales averaged a single lunge per dive, lunging primarily in a horizontal orientation, with limited maneuvering compared to other study sites. Our results indicate that some elements of humpback whale foraging behavior are conserved across environments, but that the shallow depths in our study area constrain how animals are able to feed. The relatively high lunge rates we observed suggest this area is an important foraging ground. However, foraging in shipping channels increases the risk of ship strikes, which frequently occur in this area.

Identification of Key Habitats of Bowhead and Blue Whales in the OSPAR Area of the North-East Atlantic—A Modelling Approach towards Effective Conservation

Effective protection of highly mobile and data-poor species constitutes a great challenge amid growing ocean exploitation and use. Blue whales and bowhead whales in the North-East Atlantic face several threats, such as climate change, ship strikes, pollution, and entanglement in fishing gear. Consequently, the OSPAR (“Oslo-Paris Convention for the Protection of the Marine Environment of the North-East Atlantic”) Commission recognised their need for protection and included them on the OSPAR List of Threatened and/or Declining Species. Two actions to protect these endangered species that OSPAR Contracting Parties have agreed on are (i) identifying areas that play an essential role in the species’ life cycle—subsequently called key habitats, and (ii) ensuring that those key habitats are covered by OSPAR marine protected areas (MPAs). In addition, OSPAR has committed to expanding its network of MPAs and other effective area-based conservation measures by 2030 to cover at least 30% of the OSPAR maritime area (termed the 30 × 30 target) from today’s approx. 11%. In this paper, we present the results of modelling key habitats for the bowhead and blue whales in the North-East Atlantic, including Arctic waters. Due to the sparse data situation for these species, we apply presence-only modelling methods. As this method can, in principle, produce somewhat biased results, we recommend that systematic, regular surveys on these species in Arctic waters be significantly intensified for future analyses to overcome the data paucity and allow using presence–absence/count data modelling approaches. Key habitats of blue whales were identified between Iceland and Svalbard, extending to the Azores. For bowhead whales, key habitats were identified in the Fram Strait. However, our findings show that only 11.8% of blue whale key habitats and 4.1% of bowhead whale key habitats are currently covered by OSPAR MPAs. To protect 30% of key habitats for these species in the most efficient way, our analyses suggest that suitable areas to designate new OSPAR MPAs are located around the Azores for blue whales and in the Fram Strait for bowhead whales. With these additional MPAs, OSPAR would substantially improve the protection of the two endangered species and, at the same time, progress towards its 30 × 30 target.

Experimental and numerical study on influence of impact mass and velocity on failure mode of RC columns under lateral impact

Reinforced concrete (RC) structures may encounter impact loads during service life, such as vehicle collisions, ship strikes, and explosions. Limited existing impact tests on RC columns and piers have yet to fully reveal the column impact performance and its relationship with structural or load parameters. To explore the effects of impact mass and velocity, which determine the impact energy, on the impact performance of RC columns, pendulum impact tests on nine RC columns were performed utilizing a specially designed loading setup. The test variables included the impact mass and velocity of the pendulum, as well as the slenderness ratio and stirrup ratio of the columns. During the tests, the impact force and velocity of the pendulum, as well as the axial force, displacement, and acceleration of the columns, were measured. Additionally, the damage evolution of each specimen was recorded using a high-speed camera. One-side shear failure, two-side shear failure near the impact point, and shear failure at the column bottom end were observed during the tests. The results indicated that, under similar impact energy, as the impact velocity increased, the specimens with the low stirrup ratio transitioned from one-side shear failure to two-side shear failure. An enhancement in the impact resistance of the columns was observed when the stirrup ratio was increased, or the slenderness ratio decreased. For the enhanced columns, shear failure was avoided at lower impact velocities; however, at the maximum impact velocity, end shear failure or one-side shear failure yet occurred. Additionally, a parametric analysis using LS-DYNA finite element software further clarified the effects of impact velocity and mass on the dynamic response and failure mode of RC columns.

Whalestrike: An R package for simulating ship strikes on whales

whalestrike: An R package for simulating ship strikes on whales

Fin Whale Balaenoptera physalus Historical Sightings and Strandings, Ship Strikes, Breeding Areas and Other Threats in the Mediterranean Sea: A Review (1624–2023)

A review of the last 399 years (1624–2023) on fin whales (Balaenoptera physalus) in the Mediterranean Sea was conducted, based on an extensive compilation of records published in the scientific literature, technical reports, public databases, journals, and social media. A total of 10,716 sightings and 575 mortality events have been computed, analysed by semesters and mapped in order to compare the summer–winter seasons especially and their implications on migration–residence. Visual and acoustic detections, feedings, migrations, primary production areas (chlorophyll), threats and causes of death and their relations have been addressed, and a mini-review on heavy metals and pollutants has been carried out on fin whales in the Mediterranean Sea. Mortality events were most frequent between November and April, coinciding with the decreased sighting period. Ship strikes posed the greatest threat, peaking between May and October, when marine traffic tends to increase in the Mediterranean Sea. Two populations coexist in the Mediterranean Sea, one resident and the other migratory, the latter using the Strait of Gibraltar for its biannual movements. Two areas with a presence of calves (up to 7 m in length) between October and February were detected: one scattered in the northern Mediterranean and the Strait of Gibraltar and its surroundings. A critical zone for collisions has been established according to the results for fin whales in the Mediterranean Sea.

A longitudinal study of endocrinology and foraging ecology of subadult gray whales prior to death based on baleen analysis

Individual-level assessments of wild animal health, vital rates, and foraging ecology are critical for understanding population-wide impacts of exposure to stressors. Large whales face multiple stressors, including, but not limited to, ocean noise, pollution, and ship strikes. Because baleen is a continuously growing keratinized structure, serial extraction, and quantification of hormones and stable isotopes along the length of baleen provide a historical record of whale physiology and foraging ecology. Furthermore, baleen analysis enables the investigation of dead specimens, even decades later, allowing comparisons between historic and modern populations. Here, we examined baleen of five sub-adult gray whales and observed distinct patterns of oscillations in δ15N values along the length of their baleen plates which enabled estimation of baleen growth rates and differentiation of isotopic niche widths of the whales during wintering and summer foraging. In contrast, no regular patterns were apparent in δ13C values. Prolonged elevation of cortisol in four individuals before death indicates that chronic stress may have impacted their health and survival. Triiodothyronine (T3) increased over months in the whales with unknown causes of death, simultaneous with elevations in cortisol, but both hormones remained stable in the one case of acute death attributed to killer whale predation. This parallel elevation of cortisol and T3 challenges the classic understanding of their interaction and might relate to increased energetic demands during exposure to stressors. Reproductive hormone profiles in subadults did not show cyclical trends, suggesting they had not yet reached sexual maturity. This study highlights the potential of baleen analysis to retrospectively assess gray whales' physiological status, exposure to stressors, reproductive status, and foraging ecology in the months or years leading up to their death, which can be a useful tool for conservation diagnostics to mitigate unusual mortality events.

DNA from dives: Species detection of humpback whales (Megaptera novaeangliae) from flukeprint eDNA

AbstractNorthern British Columbia has been identified as an important habitat for several coastal cetacean species, including humpback whales (Megaptera novaeangliae). This species is listed as being of “Special Concern” under Canada's Species at Risk Act, partly due to data deficiencies concerning genetic population structure and demographics in British Columbia. Anthropogenic activities threaten North Coast humpback whale populations, with particular concern for the impact of vessel noise, entanglement, and ship strikes. Current methodology (i.e., biopsy sampling) for obtaining cetacean genetic data is invasive, challenging, and costly; therefore, there is an urgency to develop effective and minimally invasive methodologies for efficiently collecting this data. Environmental DNA (eDNA) has been identified as an ideal tool for monitoring the presence and distribution of numerous species within marine ecosystems; however, the feasibility for cetaceans is not yet well established. In this study, we opportunistically collected targeted 1 L seawater eDNA samples from flukeprints when individual humpback whales were observed diving between the years of 2020 and 2022. A total of 93 samples were collected from individual humpback whales identified using a photographic identification catalogue. We successfully detected humpback whale eDNA in 28 samples using novel species‐specific qPCR primers (~500 mL of sample), with relatively equal successful detection between immediate (0 days) and delayed (up to 10 days) sample filtration. Here, we have validated a qPCR assay for detecting humpback whale DNA from flukeprints and highlighted the future optimizations required to improve the potential application of flukeprint eDNA for conservation management.

New urban habitat for endangered humpback whales: San Francisco Bay

Abstract As populations of large whales recover from whaling, species that forage and breed in coastal waters, including the humpback whale (Megaptera novaeangliae), increasingly overlap with human activities. This represents a potential hazard in locations worldwide subject to intensive vessel traffic, including New York, Panama City and Brisbane. Historically, humpback whales were not considered part of San Francisco Bay's fauna, except for a few ‘lost’ whales that wandered into the estuary. An unprecedented influx of humpback whales into highly urbanized San Francisco Bay began in 2016. Research efforts in 2016–2018 from vessels and shore resulted in 496 photo‐identification records plus 319 visual sightings. Sixty‐one individuals were photo‐identified, of which 80% (n = 49) used the bay on multiple days (range = 2 to 39), and 34% (n = 21) were resighted in successive years. Whales photographed in San Francisco Bay were found to belong to distinct population segments listed as endangered and threatened under the U.S. Endangered Species Act. Whales moved in and out of the bay seasonally (April–November). Habitat use patterns indicated movements farther into San Francisco Bay correlated positively with high tides. Humpback whales were visually observed lunge feeding on northern anchovy (Engraulis mordax) at the surface. Analysis of dive patterns by three tagged whales confirmed subsurface feeding when surface feeding was not apparent. The use of San Francisco Bay and adjacent waters by recovering populations of humpback whales exacerbates the potential for collisions with vessels, entanglement in fishing gear, and harassment by recreational vessels. The most pressing conservation concern is the risk of ship strikes, observed where humpback whales occur near active seaports.

Annex H: Bycatch and Ship Strikes of Large Cetaceans Reported in the National Progress Report Database

How to cite: International Whaling Commission, 2023. Report of the Scientific Committee: Annex H. J. Cetacean Res. Manage. (Suppl.) 24: 250-270.

The WhaleReport Alert System: Mitigating threats to whales with citizen science

Ship strikes are a pervasive threat to cetaceans globally. Real-time observations of cetaceans reported by citizen scientists unlock an opportunity to develop ship strike mitigation tools. The Ocean Wise Sightings Network (OWSN) is an example of a long-running and expansive citizen science program. The OWSN curates sightings data collected by coastal communities, mariners, and tourists into a database that can be utilized to monitor the 23 cetacean species inhabiting British Columbia and Washington State waters. Recently, the OWSN mobilized real-time sightings data into a mitigation tool, the WhaleReport Alert System (WRAS), which alerts professional mariners to the presence of cetaceans within their vicinity, allowing them to take action (e.g., slow down or divert course), to mitigate the risk of ship strike. The success of the WRAS (550 registered users) can be largely attributed to outreach events conducted in coastal communities which recruit new observers who report sightings to the WhaleReport app. Partnering with mariners to develop the WRAS has resulted in its continued support from and use by marine industry. We highlight the critical role of a sightings network for mitigating threats to cetaceans, emphasize the need to collaborate with marine industry, non-governmental, and government bodies to support endorsement of the tool, and stress the importance of metrics to evaluate success of the WRAS. This approach taken by Ocean Wise has resulted in the delivery of >20,000 WRAS alerts and is a framework which could be integrated into existing sightings networks globally to mitigate the risk of ship strikes on cetaceans.

SEADETECT: developing an automated detection system to reduce whale-vessel collision risk

With the continuous intensification of marine traffic worldwide, whale-vessel collisions at sea (or “ship strikes”) have become one of the primary causes of mortality for cetaceans and a widely recognised cause of concern for human safety and economic losses. The Mediterranean Sea is a global hotspot for whale-vessel collisions, with one of the highest rates involving large cetaceans, especially the endangered fin whales (Balaenoptera physalus) and sperm whales (Physeter macrocephalus). Evidence indicates that both species are experiencing higher chances of a fatal collision than what predictions have estimated so far, with ship strikes being the main human-induced threat in the area. Regional and international organisations have stressed the need to address the issue by investigating the projected impacts of ship strikes on whale populations and by identifying possible mitigation measures to reduce chances of collision. Amongst the most popular and feasible options, there is the improvement of animal detection during navigation. Here, we present SEADETECT, a LIFE project that aims at developing an automated detection system to reduce vessel collision risk with marine mammals and unidentified floating objects (UFOs), combining state-of-the-art and novel technologies with existing approaches in the study of large whale ecology. This detection system consists of three elements; an automated onboard detection system composed of several sensors, a real-time passive acoustic monitoring (PAM) network at sea and a real-time detection-sharing and alert system (REPCET®). In this paper, we propose the development of a mitigation measure framework tailored for the issue of collision with fin and sperm whales in the north-western Mediterranean Sea, but that has the transferability features necessary for its application in other high-risk areas for ship strikes worldwide.

What is The Most Common Human Factor That Threatens Marine Species in The North Atlantic Ocean Region?

In the North Atlantic Ocean Region, the greatest human threat to marine species is ship strikes. The many different species that reside in the ocean are affected greatly by various human factors such as pollution, ship traffic, infrastructure in the water and net entanglement. In this paper we establish that ship strikes cause the most damage to species in the North Atlantic region. We found that ship traffic affects many species greatly, from being the cause of death for 53% of the 40 Right whales autopsied between 1970 and 2006, to hundreds of sturgeon across three distinct regions killed by this method. Ship strikes are the most damaging factor, especially to the larger marine animals in the ocean such as whales and sturgeon. Our results not only show how one factor harms these species to a great extent, but how humans, through many different forms, greatly threaten the survival of other species. We conclude that these factors will continue to harm and threaten the well-being of species unless concerted action is taken to mitigate the effects.

Kinematics and energetics of foraging behavior in Rice’s whales of the Gulf of Mexico

Rorqual foraging behavior varies with species, prey type and foraging conditions, and can be a determining factor for their fitness. Little is known about the foraging ecology of Rice’s whales (Balaenoptera ricei), an endangered species with a population of fewer than 100 individuals. Suction cup tags were attached to two Rice’s whales to collect information on their diving kinematics and foraging behavior. The tagged whales primarily exhibited lunge-feeding near the sea bottom and to a lesser extent in the water-column and at the sea surface. During 6–10 min foraging dives, the whales typically circled their prey before executing one or two feeding lunges. Longer duration dives and dives with more feeding-lunges were followed by an increase in their breathing rate. The median lunge rate of one lunge per dive of both animals was much lower than expected based on comparative research on other lunge-feeding baleen whales, and may be associated with foraging on fish instead of krill or may be an indication of different foraging conditions. Both animals spent extended periods of the night near the sea surface, increasing the risk for ship strike. Furthermore, their circling before lunging may increase the risk for entanglement in bottom-longline fishing gear. Overall, these data show that Rice’s whale foraging behavior differs from other lunge feeding rorqual species and may be a significant factor in shaping our understanding of their foraging ecology. Efforts to mitigate threats to Rice’s whales will benefit from improved understanding of patterns in their habitat use and fine-scale ecology.

Whale shark abundance forecast: The interannual hotspot effect

Abstract Each year, whale sharks (Rhincodon typus) aggregate in the northern Gulf of California at Bahia de los Angeles, a small coastal village that recently developed whale shark swimming as economic activity during the summer and autumn. Since the number of animals using the bay fluctuates annually, we aimed to predict it 1 month before each whale shark season. We based our modelling approach on the hypothesis that interannual warming conditions would spatially restrict whale shark habitats, triggering larger aggregations in areas that remain productive. We photo‐identified whale sharks while surface feeding in Bahia de los Angeles during a 13‐year period, which allowed us to estimate a local abundance index per year through mark–recapture techniques. Then, we fitted these abundances as a function of several competing model structures, based on means of sea surface temperature and chlorophyll‐a, as well as their interannual anomalies from the linear trend, during spring, within the best‐known range of the species in the northern Gulf of California. The results of the ecological model showed that whale sharks visit Bahia de los Angeles in larger numbers during extreme warming conditions, with relatively high surface chlorophyll‐a concentrations, which was especially evident during the 2014–2016 northeast Pacific Marine Heatwave and El Niño. Presumably, the overall reduction in surface productivity associated with these events forced whale sharks to restrict their summer–autumn habitat to productivity hotspots, including Bahia de los Angeles. Our model allowed us to predict the number of animals visiting the site before each season starts, which has crucial proactive management implications, such as allowing authorities to regulate the ecotourism effort dynamically to reduce the probability of ship strikes and/or excessive stress to the animals. We propose an abundance baseline from the prediction for neutral interannual conditions. Synthesis and applications. We recommend local authorities apply the model described in this study during the late spring of each year to obtain predictions of the upcoming whale shark abundance and establish the maximum ecotourism effort allowed accordingly.

Fuzzy cognitive mapping as a tool to assess the relative cumulative effects of environmental stressors on an Arctic seabird population to identify conservation action and research priorities

Abstract In the Arctic, chemical contaminants, shipping, oil pollution, plastic pollution, changing habitats in relation to climate change and fisheries have been identified as environmental stressors to seabirds such as Fulmarus glacialis (northern fulmar; qaqulluk; ᖃᖁᓪᓗᖅ), but rarely have these stressors been considered within a cumulative effects framework in this species which is currently showing a declining populations trend. As a novel tool to understand cumulative effects within a conservation context, we applied a fuzzy cognitive mapping (FCM) approach that allows experts to arrange key factors and their interrelationships, organizing their understanding of the components of a complex issue into a graphical representation; a ‘cognitive map’. This process was grounded in local environment concerns as documented in several Nunavut‐specific reports and discussions, and worked with western‐trained seabird experts with knowledge of northern fulmar populations to assess the inter‐related environmental threats to fulmars as a way to combine these stressors in a cumulative effects framework and identify conservation actions and knowledge gaps. We found strong agreement that the main stressors affecting northern fulmar populations in Canada include pollution (11% total influence (TI)), shipping activities (16% TI), hunting and fishing (18% TI) and mining/oil and gas exploitation activities (22% TI). The indirect influence of threats on northern fulmar population size (57% TI) exceeded the total direct influence (43% TI), emphasizing the value of cognitive mapping in cumulative effects assessment for a more holistic understanding of interacting stressors. Participants expressed substantial uncertainty regarding the strong relationships leading from the concepts, commercial fishing activity in the BBDS and the North Atlantic fisheries activity, indicating that these potential stressors require more research. Similarly, uncertainty was expressed about the potential effects of zodiac traffic, ship strikes of northern fulmar, number of oil spills and magnitude of oil spills on northern fulmar. By characterizing individual factors as manageable or not, we determined that stressors are largely manageable with enforcement of existing policies (58% TI)—importantly, fishing activities were both highly influential on fulmars and deemed manageable, which will inform ongoing co‐management planning in the region.

Estimating the impact of ship strikes on the Mediterranean fin whale subpopulation

The Mediterranean fin whale (Balaenoptera physalus) subpopulation is under threat from collisions with ships. Given the international dimension of the issue, the French, Italian, Monegasque and Spanish governments have proposed a Particularly Sensitive Sea Area (PSSA), i.e., a management zone of the International Maritime Organization (IMO), in which mandatory and voluntary protective measures can be implemented. Defining the risk and its impact at the subpopulation level is required to improve the chances of an IMO acceptance for such a proposal. While previous research partially succeeded in defining the collision risk, its impact on the subpopulation has not been thoroughly evaluated, especially at the spatial scale of the envisioned PSSA. Our study uses the carcass recovery approach to estimate the number of deadly collisions within the proposed PSSA. We then assess the probability that this number exceeds three management rules: Potential Biological Removal (PBR), Alert Reference Point (ARP) and Critical Reference Point (CRP). These management rules describe thresholds beyond which (a) the incidental mortality may prevent the recovery of the population within 100 years (PBR), (b) there is a cause for concern about incidental mortality (ARP), and (c) there is a critical need to lower the incidental mortality (CRP). We conclude that mortality from collisions alone is in excess of PBR. Taking into account confirmed and suspected collisions in strandings in calculations, the collision mortality exceeds ARP; this threshold being considered unacceptable by some international organisations. Additionally, there is almost a 35% chance that the mortality due to ship strikes exceeds the CRP, likely resulting in a population decline. The probability of anthropogenic mortality exceeding CRP is 60% if we include the fishery-related mortality in stranding (i.e., taking into account the total incidental mortality from bycatch and ship strikes). The PSSA proposal could use our approach to estimate the impact of collisions and assess the effectiveness of implemented protective measures. However, it is important to highlight that the IMO process for establishing a PSSA is lengthy, and our findings show that immediate action is required, as there is a high probability that the ship strike and fishery mortality is beyond the critical threshold fixed by the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic area (ACCOBAMS).

Osteo-pathological analysis provides evidence for a survived historical ship strike in a Southern Hemisphere fin whale (Balaenoptera physalus).

The life history of a fin whale (Balaenoptera physalus) caught during whaling operations in the 1950s was partly reconstructed. 3D surface models of the bones of the skeleton curated at the Zoological Museum of Hamburg were used for an osteopathological analysis. The skeleton revealed multiple healed fractures of ribs and a scapula. Moreover, the processus spinosi of several vertebrae were deformed and arthrosis was found. Together, the pathological findings provide evidence for large blunt trauma and secondary effects arising from it. Reconstruction of the likely cause of events suggests collision with a ship inflicting the fractures and leading to post traumatic posture damage as indicated by skeletal deformations. The injured bones had fully healed before the fin whale was killed by a whaler in the South Atlantic in 1952. This study is the first in-detail reconstruction of a historical whale-ship collision in the Southern Hemisphere, dating back to the 1940s, and the first documentation of a healed scapula fracture in a fin whale. The skeleton provides evidence for survival of a ship strike by a fin whale with severe injuries causing long-term impairment.

Increasing numbers of ship strikes in the Canary Islands: proposals for immediate action to reduce risk of vessel-whale collisions

The Canary Islands, known for their extraordinarily high cetacean species diversity, have witnessed a rapid expansion in fast and high speed ferry traffic during the past few years. At the same time, ship strikes have been increasingly reported. 556 cetacean carcasses, found ashore, or reported, in the Canary Islands between 1991 and 2007, were examined. 59 strandings (10.6%) were found to involve vessel-whale collisions, the great majority of strandings (58%) occurred on Tenerife. Species most affected were sperm whales (Physeter macrocephalus, n = 24, 41%), pygmy sperm whales (Kogia breviceps, n = 10, 17%), Cuvier’s beaked whales (Ziphius cavirostris, n = 7, 12%), short-finned pilot whales (Globicephala macrorhynchus, n = 6, 10%) and at least three baleen whale species (n = 9, 15%). Twenty six animals (44%, n = 42) were either calves or juveniles, and one was a newborn. The temporal distribution of strandings indicates that lethal strikes have increased in recent years. Most ship strikes, assumingly by large and fast moving vessels, probably resulted in the death of the animals, as indicated by severe injuries such as huge slashes, cuts, broken vertebrae or animals separated into halves. Given these numbers and the widely accepted fact that only a portion of ship strikes will be recorded due to under-reporting and carcasses drifting away or sinking, ship strikes appear to be a major threat to cetaceans in the Canary Islands, especially to sperm whales. Moreover, the issue is a matter of human safety, as crew and passengers are at risk of being harmed, too. In this situation, a number of measures to mitigate the risk of ship strikes are recommended as a matter of high priority. These include the placement of dedicated look-outs on fast moving vessels, the shift of ferry transects where feasible, a speed limitation for local high-risk areas where cetacean abundance is notably high, the introduction of an obligatory reporting system of vessel-whale collisions and the conduction of detailed studies dealing with this pressing issue.

Modelling ship strike risk to fin, humpback and killer whales in British Columbia, Canada

Many cetacean species are susceptible to mortality or serious injury from vessel collisions. Spatially explicit assessments of risk per whale can help identify potential problem areas to guide appropriate mitigation measures. Canada’s Pacific waters host high cetacean densities and intense maritime traffic, and the issue of vessel collisions has taken on a high priority in British Columbia (BC) recently due to several major industrial development applications. Spatially-explicit statistical modelling and Geographic Information System (GIS) visualisation techniques identified areas of overlap between shipping activity and waters used by humpback, fin and killer whales. Areas of highest risk were far removed from areas with highest concentrations of people, suggesting that many beach-cast carcasses could go undetected. With few exceptions, high-risk areas were found in geographic bottlenecks, such as narrow straits and passageways. Port expansion and a proposed pipeline for carrying oil from Alberta to BC’s north coast (with associated oil tanker traffic) would increase ship strike risk for all three species. The risk assessments illustrate where ship strikes are most likely to occur, but cannot estimate how many strikes occur. Propeller wounds on live killer whales are common in the region, and fatal collisions have been reported in BC for all three species. Procedures were used to estimate potential mortality limits in accordance with a wide range of quantitative management objectives from jurisdictions around the world. While the extent of under-reporting of ship strikes has not been evaluated, the few known cases of collisions involving fin whales suggest that mortality due to ship strike for this species may already be approaching or even exceeding mortality limits under the most risk-averse management objectives. It is hoped that risk maps may inform environmental impact assessments of marine traffic because it will be easier to plan new shipping lanes so that they avoid high-density areas for whales than it will be to move the lanes after they become entrenched.

Quantification of ferry traffic in the Canary Islands (Spain) and its implications for collisions with cetaceans

The Canary Islands, known for their high cetacean species diversity, have witnessed a rapid expansion of fast ferry traffic during the past few years. At the same time, ship strikes have been repeatedly documented. In this paper an overview of the inter-island ferry traffic in the archipelago is given. Ferry types in use (normal, fast and high speed vessels) are described, and the transects on which they operate are identified. To quantify the extent of the inter-island ferry traffic, three parameters were determined: (1) the actual transects from the different ports on the islands; (2) the number of journeys made per week on each transect; and (3) the length of each transect. Resulting numbers indicate that normal ferries travel approx. 66,000km, fast ferries travel approx. 570,000km and high speed ferries travel approx. 845,000km between islands each year. Fast and high speed ferry traffic is concentrated in the western islands. Areas of high risk for ship strikes within the archipelago are identified by comparing the location of transects with known areas of high cetacean abundance. It is argued that the Canary Islands are a hot spot for vessel-whale collisions and that a policy to counteract this situation is urgently needed.