Using Photo ID to Examine Injuries in Eastern Pacific Gray Whales (Eschrichtius robustus) Laura Conner1, Lei Lani Stelle1, William Megill2, Eduardo Najera-Hillman3, John Calambokidis4, Amber Klimek4

1 University of Redlands, Redlands, CA, USA. 2 University of Bath, Bath, UK. 3 Instituto de Ecología, Xalapa, Veracruz, México. 4 Cascadia Research Collective, Olympia, WA, USA.

Abstract

•41% of whales had injuries •Under-estimate - entire body and fatal injuries not included

•Most common type of injury = scars •Most common location of injury = flukes • Lower rates of anthropogenic injuries than other studies, but

similar rates of natural injuries • Larger population size might be minimizing the adverse

impacts of anthropogenic interactions? •Highest percentage of injuries found on whales in the PCFA

•Greater chance of injury in coastal feeding grounds? • Injured whales less inclined to complete full migration?

• Lowest percentage of injuries on whales in breeding grounds •Presence of newborn calves? •Poorer photo quality as there were fewer photos of each

individual to choose from? •Annual population growth rate for Western Pacific gray whales

is between 2.5 and 3.2% (Bradford et al. 2008), therefore it is likely similar for the Eastern Pacific grays. •2% of the whales sustaining anthropogenic injuries could be

severely affecting the growth and health of the population. • Injury caused by both natural and anthropogenic sources

•Anthropogenic injuries most likely represent more of a threat to smaller populations of whales than to the Eastern Pacific gray whale.

• To reduce anthropogenic injuries: •Obey distance rules to avoid hitting whales

• (Stay >100m away) •Regulate the boat traffic in calving lagoons and feeding

grounds • Implement marine mammal safe fishing methods

•Continue to monitor injuries in gray whales as well as other species • Investigate reasons for higher injury rate in PCFA whales •Determine if particular injuries are more common in one group

of whales

Laura Conner lauradconner@gmail.com

Dr. Lei Lani Stelle leilani_stelle@redlands.edu

•Bradford A, Weller D, Ivaschenko Y, Burdin A, Browness R. (2009) Anthropogenic scarring of western gray whales (Eschrichtius robustus). Mar. Mam. Sci. 25(1)161-175 •Bradford A, Weller D, Wade P, Burdin A, Brownell B. (2008) Population abundance and growth rate of western gray whales Eschrichtius robustus. Endang. Species Res. 6:1-14 • George J, Philo L, Hazard K, Withrow D, Carroll G, Suydam R. (1994) Frequency of killer whale (Orcinus orca) attacks and ship collisions based on scarring on bowhead whales (Balaena mysticetus) of the Bering-Chuckchi-Beaufort Seas stock. Arctic Institute of North America. 47(3):247-255 •Kraus D. (1990) Rates and potential causes of mortality in North Atlantic Right Whales (Eubalaena glacialis). Marine Mammal Science. 6(4):278-291

Scar = Scar on body or flukes (minor injury)

Rake = Series of 3 or more parallel scars most likely caused by attack from killer whale (Orcinus orca)

Wound = Serious injury estimated to be deeper than 10cm, longer than 1m, or cover a larger area than 30cm (Kraus 1990)

Fluke = Missing tips of the fluke (no other associated injuries)

Entanglement = Scars from or remnants of fishing gear

Photos from CERF, British Columbia, Canada

I would like to thank the School for Field Studies, University of Redlands, Coastal Ecosystems Research Foundation, Earthwatch Institute, University of Bath, University of Victoria, and Cascadia Research Collective for their support.

1 There were only 324 individuals for which fluke and peduncle photos were obtained (the most common location of entanglement) 2 The injury percentages do not add up to 100% because some animals had more than one type of injury

Wound from boat propeller

Objectives

Methods

Future Work

Acknowledgements & References

Potential anthropogenic sources of disturbance and injury to gray whales are similar to those of other species of marine mammal and include:

• Commercial and private fishing operations • Vessel traffic • Behavior alteration •Offshore oil and gas development •Noise pollution, etc. (Moore & Clarke 2002)

Contact Information

Injury Type Percent Injured

W. Pacific Gray1

Right Whale2

Bowhead Whale3

Entanglement 18 57 -

Ship Strike 2 7 1

Rake - 9 8

Scar - 30 - 1Bradford et al. (2009), 2Kraus (1990), 3George et al. (1994)

Introduction

Rake marks from attack by killer whale

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Body Region

Results

Injuries

The coastal migration of the Eastern Pacific population of gray whales (Eschrichtius robustus) brings them into close contact with shipping lanes and fishing operations which present major anthropogenic threats. This study used photographs collected for identification of individual whales throughout their distribution to examine which body regions were susceptible to both natural and anthropogenic injury and further examine the most common types of injury to the whales. Photos were collected from calving grounds in Baja California, Mexico, feeding grounds of the Pacific Coast Feeding Aggregation, and along the migratory corridor. Photographs were entered into catalogs for identification, and then visually analyzed to determine the body regions and injuries observed. Types of injuries included: scar, wound, rake mark (from attack by orcas), entanglement, and fluke (injury on tail that does not fall into another category). The total sample size was 1662 whales. Our results indicate scars, rake marks, and entanglements represented the most common types of injuries, each occurring in about 10% of the whales. Rake marks and scars were found more often on the flukes than the body, but there was no significant difference in location of wounds when compared between the body and flukes. It is estimated that about 2% of the whales had injuries from anthropogenic sources; 1.23% had evidence of entanglement, and 0.66% had suffered wounds most likely from collisions with ships. These results represent a minimum injury level for the whales as fatalities are not accounted for, and not all regions of the whale’s body can be examined. It is important to have such baseline data in order to make informed decisions about the risks faced by gray whales so that effective management strategies can be applied to the stock.

Adapted from: Bradford et al. (2009)

* Regions 1-4 not recorded in photo ID catalogs

Table 2: Number of Whales with each Injury Type by Location

Discussion & Conclusions

Analyzed locations of injury type with body location using Chi-squared tests

•Scars and rake marks occur more on the flukes than on the body (χ2=18.4 p<0.001 and χ2=170.1 p<0.001 respectively)

•No difference between wounds on fluke and body (χ2=0.45 p>0.5)

•Overall more injuries on the fluke than on body (χ2=80.8 p<0.001)

•No difference between injuries on the right and left sides of the body (χ2=0.029 p>0.9)

Red = Body Blue = Flukes

Photos from CERF and CRC (Brian Gisborne & Jeff Jacobsen) photo ID catalogs

Figure 1: Number of Times each Body Region is Photographed

•There were more whales with injuries in the PCFA than in the breeding grounds and migratory corridor (χ2=45.6 p<0.001)

Wound

Number Injured

Injury Type Breeding

Ground PCFA Migrating Total Percent

Scar 130 186 244 560 33.7

Rake 23 51 42 116 6.98

Wound 3 5 3 11 0.66

Fluke 7 22 7 36 11.11

Entanglement 0 3 1 4 1.231

None 427 145 408 980 59.02

Total 588 377 697 1662 -

Entanglement (rope around peduncle)

Entanglement (rope around body)

Fluke missing tip (also has rake marks)

Scar

Injury Definitions

Table 1: Previous studies have found the following types and percentages of injuries in Western Pacific gray whales, Western North Atlantic right whales, and bowhead whales.

Use photo ID data to: • Identify body locations most prone to injury •Determine the most common types of injuries •Offer baseline data for future studies •Compare injury rates for different areas of their migration

(Pacific Coast Feeding Aggregation, migratory corridor and breeding ground)

Map modified from: www.worldatlas.com

Migration Route

Pacific Coast Feeding Aggregation (PCFA)

Summer Feeding Grounds

Coastal Ecosystems Research Foundation, Cape Caution, BC

Cascadia Research Collective, Cascadia, WA

University of Redlands , South Bay, CA

Laguna San Ignacio, BCS

School for Field Studies, Puerto San Carlos, BCS

Study Areas:

Winter Breeding Grounds

In the field

•Performed transects in 8-30m motorboats

•Took photographs of dorsal sides and fluke (when possible)

•Record data: GPS location, time, frame #, behavior, etc.

In the lab

•Matched photos to ID catalogs to ensure individuals are not double-counted

•Determined which body regions are included in the photos (see whale schematic in figure 1)

•Examined photos to look for evidence of injuries

•Chi-squared tests performed to determine if there were significant differences in body location of injuries and in injury rates with geographic locations