prnpr shark skate inventory

Multi-Species Inventory of Elasmobranchs (Sharks and Skates)

in Pacific Rim National Park Reserve of Canada

Parks Canada Species at Risk Inventory Fund

Project Number: SARINV07-23

March 31, 2008

Jim McCaffrey, Queen Charlotte Islands 1959

Jennifer L Yakimishyn, MSc

Marine Researcher

Pacific Rim National Park of Canada

Multi-Species Inventory of Sharks and Skates (Elasmobranchs) in PRNPR – 2007-08

Table of Contents

1. Abstract ....................................................................................................................................... 1 2. Introduction................................................................................................................................. 3 3. Methods....................................................................................................................................... 5

3.1 Current and Historical Elasmobranch Observations............................................................. 5 3.2 Spatial Analysis for Elasmobranch Observations................................................................. 8 3.3 Skate Egg case Surveys ...................................................................................................... 11

4. Results....................................................................................................................................... 13 4.1 Current and Historical Elasmobranch Observations........................................................... 13 4.2 Kernel Density Surface Maps for Elasmobranch Observations ......................................... 25 4.3 Skate Egg case Surveys ...................................................................................................... 29

5. Discussion ................................................................................................................................. 35 6. Future Recommendations ......................................................................................................... 39 7. Literature cited .......................................................................................................................... 40 Appendix 1 - Report a Shark Skate or Ray Poster........................................................................ 42 Appendix 2 - Elasmobranch Survey Form.................................................................................... 44 Appendix 3 - Photographs of Elasmobranch Records .................................................................. 46

ii


List of Figures Figure 1. Example of skate egg case survey data on the Kestrel website....................................... 7 Figure 2. Perspective view of the ArcMap quartic approximation of a Gaussian kernel for a

single point, a single line and their sum................................................................................ 10 Figure 3. Formula used to calculate the height of the kernel at each location on the plane. ........ 10 Figure 4. Distribution of all elasmobranch observations. ............................................................. 15 Figure 5. The recorded big skate observations from 1887 to 2007. ............................................. 19 Figure 6. The 8 recorded basking shark observations from 1998 to 2006 (6 confirmed

observations). ........................................................................................................................ 19 Figure 7. The 45 recorded blue shark observations from 1994 to 2007. ...................................... 20 Figure 8. The 10 bluntnose sixgill shark and 3 broadnose sevengill shark observations from 1941

to 2007. ................................................................................................................................. 20 Figure 9. The 9 great white shark observations from 1963 to 2007 (4 confirmed observations). 21 Figure 10. The 15 salmon shark observations from 1949 to 2007................................................ 21 Figure 11. The 49 spiny dogfish shark observations from 1939 to 2007. .................................... 22 Figure 12. The 17 tope shark observations from 1947 to 2007. ................................................... 22 Figure 13. All elasmobranch observations made in 2007............................................................. 23 Figure 14. Number of individual elasmobranch species observed each month in 2007............... 24 Figure 15. Kernel density surface of all elasmobranch observations recorded in 2007 using three

different cell sizes (1000 m, 500 m, and 100 m). ................................................................. 26 Figure 16. Kernel density surface of all elasmobranch observations recorded in 2007 using four

different search radii (1000 m, 2500 m, 4000 m, 5000 m). .................................................. 27 Figure 17. Kernel density surface of all elasmobranch observations recorded in 2007 using four

different 4000 m search radius and 100 m cell size with geographic locations labelled...... 28 Figure 18. Kernel density surface of all elasmobranch observations from all years combined that

occurred in the southern waters of Vancouver Island with geographic locals labelled........ 28 Figure 19. Skate egg case survey areas for the five surveys conducted from February to

December in 2007. ................................................................................................................ 30 Figure 20. Skate egg case survey areas for the three surveys conducted from January to February

in 2008. ................................................................................................................................. 31 Figure 21. Three egg case species found and identified during the egg case surveys.................. 32 Figure 22. Survey areas and skate egg case species and locations for surveys conducted in 2007.

Survey 4 was not included because there were no egg cases found. .................................... 33 Figure 23. Survey areas and skate egg case species and locations for surveys conducted in 2008.

............................................................................................................................................... 34

List of Tables Table 1. Elasmobranch and skate egg case survey dates and locations.......................................... 8 Table 2. Summary of elasmobranch species recorded during this study and their known

distribution in the northeast Pacific. ..................................................................................... 14 Table 3. All elasmobranch observations that occurred within the boundaries of PRNPR and in

waters adjacent to GINPR..................................................................................................... 16

iii


1. Abstract

Sharks and skates are a group of cartilaginous fish called elasmobranchs that occur in

coastal waters of British Columbia. Shark and skate populations are globally declining due to

their vulnerability to fishing pressure because they are long-lived, slow to mature and produce

few young. Overfishing of top predatory sharks has cascading effects on the balance of marine

food webs. Thirteen sharks species exist in the marine waters surrounding Pacific Rim National

Park Reserve (PRNPR) and the Committee on the Status of Endangered Wildlife in Canada

(COSEWIC) has designated six of these species as species at risk. The basking shark is listed as

endangered, the sixgill, tope and brown cat sharks are listed as special concern, and the great

white and blue sharks are data deficient. In this study, historical and current locations were

recorded for all of these species, except the brown cat shark.

This project compiled a total of 284 current and historical shark and skate sightings from

local community members and organizations such as the Royal British Columbia Museum,

PRNPR, and Strawberry Island Research Society. Thirty-seven of these observations occurred

within the boundaries of PRNPR and 32 occurred in waters surrounding Gulf Islands National

Park Reserve (GINPR). Overall, in 2007, 84 elasmobranch observations were made in waters

along on the west coast of Vancouver Island and consisted of eight species and one unidentified

shark species. The highest numbers of sightings were recorded from July to September. Eight

surveys of skate egg cases were also conducted in the spring of 2007 ad 2008 in the Long Beach

unit of PRNPR. The big and longnose skate egg cases occurred in the highest numbers in

February in the Long Beach north area.

1


I compiled all distributional elasmobranch and skate egg case data points into databases

(\\PRP-WDNS-

Multi\Groups\Common\Jenn\sharks_and_rays\databases\elasmobranch_db_2007.xls, \\PRP-

WDNS-Multi\Groups\Common\Jenn\sharks_and_rays\databases\Skate_eggcase_surveys.xls),

which is available to Species At Risk (SAR) proponents and COSEWIC for status report

preparation and review. For this report the distributional data points were used to generate multi-

elasmobranch species distribution maps. The elasmobranch distribution database was also input

into the NatureServe Kestrel data management system and therefore is accessible to internal and

external government agencies, non-government organizations, and members of the conservation

community.

Future project recommendations include working with local First Nations communities to

compile Traditional Ecological Knowledge on elasmobranch species, provide elasmobranch

identification training opportunities to local sportfishing guides, continue interview style surveys

on local docks, continue surveys of skate egg case in Long Beach north area in February, and use

communication tools to deliver Species at Risk and elasmobranch information to the local

community and adjacent urban centers.

2


2. Introduction

Elasmobranchs are a group of cartilaginous fish that inhabit the coastal marine waters of

British Columbia (BC) and include sharks and skates. Shark populations, are globally declining

due to their vulnerability to fishing pressure because they are long-lived, slow to mature and

produce few young (Baum et al 2003). Overfishing of top predatory sharks has cascading effects

on the balance of marine food webs (Myers et al 2007). Consequently, determining the

distribution and status of sharks and skates in coastal BC is an important component to determine

the health of the coastal marine ecosystems.

Approximately thirteen shark and eleven skate species exist in the marine waters within

and adjacent to Pacific Rim National Park Reserve (PRNPR). The Committee on the Status of

Endangered Wildlife in Canada (COSEWIC) assessed the status of seven elasmobranch species

at their May 2007 meeting. The seven species include the brown cat shark (Apristurus brunneus),

the sandpaper (black) skate (Bathyraja interrupta), the big skate (Raja binoculata), the longnose

skate (Raja rhina), the tope (soupfin) shark (Galeorhinus galeus), the bluntnose sixgill shark

(Hexanchus griseus), and the basking shark (Cetorhinus maximus). The brown cat shark was

listed as data deficient, all three skate species were listed as not at risk, the tope and bluntnose

sixgill sharks were listed as special concern, and the basking shark was listed as endangered. In

addition to these seven reports, the white shark (Carcharodon carcharias) and the blue shark

(Prionace glauca) were assessed by COSEWIC in 2006 (COSEWIC 2007). However, the status

of both Pacific populations of these species could not be determined due to data deficiency. The

provincial red and blue lists also do not currently track shark and skate species and consequently

this list is incomplete. On an international scale both white shark and the basking sharks are

listed as vulnerable by the Convention on International Trade in Endangered Species (CITES)

3


(CITES 2007). In addition, all seven species except the longnose skate are also red-listed by the

World Conservation Union (IUCN) (IUCN 2007).

Knowledge gaps are evident for this group of marine fish because of the difficulty in

studying these highly mobile, elusive and long-lived marine species. However, a multi-species

inventory is appropriate for these species because of overlapping ranges and similar sighting

requirements. The range of the nine elasmobranch species discussed above includes the marine

waters surrounding and within Pacific Rim National Park Reserve (PRNPR). More specifically,

the range of the three skate species is limited to the Northeast Pacific with an 80% or greater

chance of occurrence in waters surrounding and within PRNPR. Most of the shark species have a

circumglobal distribution, except for the brown cat shark whose distribution is limited to the

temperate Eastern Pacific seas with a 60% or greater chance of occurrence. Although the tope

and bluntnose sixgill sharks are found globally their occurrence in waters surrounding and within

PRNPR is greater than 60%. Whereas, the chance of encountering blue, white and basking

sharks is 20% in the southern waters of Vancouver Island (FishBase 2007). In summary, there is

a high occurrence of six of the nine elasmobranch species assessed by COSEWIC in the marine

waters surrounding and within PRNPR.

Consequently, PRNPR plays an important role in identifying priority areas for

conservation of these species through the compilation of local historical and current distribution

data. The main objectives of this project include compiling historical elasmobranch records from

PRNPR, the Royal British Columbia Museum (RBCM), and local community knowledge for

areas within and surrounding PRNPR. In addition, local knowledge has recently been

acknowledged by COSEWIC as important information to include in their assessment process

(COSEWIC 2008).

4


In this study, historical records included distributional data collected along the entire

coast of BC. I recorded current elasmobranch observations by interviewing local sportfishers and

community members working on the water. At sea behavioural observations and locations

provided valuable information not recorded by the fisheries observation program (Scott Wallace

personal communication). Park employees and park visitors also made opportunistic

observations that were included in the dataset. Researchers and park wardens also did skate egg

case surveys in the Long Beach unit of PRNPR in the spring and winter months. All

distributional data was compiled into a database and is available to Species At Risk (SAR)

proponents and COSEWIC for status report preparation and review. For this report the

distributional data was used to generate multi-elasmobranch species distribution maps. Lastly,

this project provides Parks Canada with a starting point for future SAR recovery planning

priorities.

3. Methods

3.1 Current and Historical Elasmobranch Observations

Individual reports of current and historical elasmobranch observations and locations

ranged from the Aleutian Islands southward to the state of Washington. However, the focal area

for current observations was off the southern west coast of Vancouver Island and the southern

Gulf Islands. I surveyed the local communities of Ucluelet, Tofino, Bamfield and Port Renfrew

for current elasmobranch observations. Information collected included the reporting person and

their contact information, the date, time and location of the observation, species identification

and description, behavioural observations and any additional comments. Two methods were used

in conjunction to obtain elasmobranch observations: 1) notice posting and 2) dockside interview

5


surveys. The notice developed contained all the requested observation information with a contact

number and email address (Appendix 1). The notice was posted at local docks in the

communities of Ucluelet, Tofino, Bamfield and Port Renfrew and distributed to local community

members including sportfishers, whale watching and scuba dive business operators.

Using interview style surveys (Appendix 2) I interviewed sportfishers at the local docks

of Ucluelet, Tofino and Port Renfrew from June to September (Table 1). I also distributed the

surveyor forms to the local Department of Fisheries and Oceans (DFO) creel surveyors in

Ucluelet and Tofino to include in their survey. Lastly, I collected historical elasmobranch

observations from the RBCM, sportfishers, whale watching operators, local naturalists such as

Rod Palm at Strawberry Island Research and Brian Gisborne owner and operator of the Juan De

Fuca Express.

Geographic coordinates for each observation were obtained by one of the two methods:

1) estimated location of the animal based on identifiable coastline and bathymetric features and

names and 2) the exact location was obtained from a handheld GPS unit. Data was compiled and

input into a Microsoft excel database (\\PRP-WDNS-

Multi\Groups\Common\Jenn\sharks_and_rays\databases\elasmobranch_db_2007.xls) and linked

to ArcMap 9.2 for spatial analysis. I also gave the elasmobranch distribution database to Whitney

Weber at NatureServe to input into the NatureServe Kestrel data management system (Figure 1,

http://kestrel.natureserve.org). Kestrel is an online system that manages biodiversity information

in Parks Canada and allows for integration and data sharing within Parks Canada as well as with

other local, provincial, federal and international government agencies, non-government agencies

and other members of the biodiversity conservation community. All future SAR inventory fund

recipients will also be required to enter their species distribution data into the Kestrel system.

6

http://kestrel.natureserve.org/


Figure 1. Example of skate egg case survey data on the Kestrel website.

7


Table 1. Elasmobranch and skate egg case survey dates and locations.

Type of Survey Survey location Survey date Elasmobranch interview style survey Ucluelet July 5, 2007 Tofino July 6, 2007 Tofino July 26, 2007 Ucluelet July 27, 2007 Ucluelet August 14, 2007 Port Renfrew August 22, 2007 Tofino August 29, 2007 Ucluelet August 30, 2007 Port Renfrew September 3, 2007 Skate egg case beach surveys Schooner February 15, 2007 Schooner April 27, 2007 Long beach May 2, 2007 Wickaninnish beach May 2, 2007 Fletchers beach December 9, 2007 Schooner January 18, 2008 South beach February 4,2008 Long beach February 4,2008 3.2 Spatial Analysis for Elasmobranch Observations

Two methods were used to map elasmobranch observations: 1) using points and 2) using

fixed kernel density surfaces. First, I mapped each elasmobranch observation as points. Both

estimated and exact geographic coordinates for each elasmobranch observation were mapped.

Maps depicting each observation as a point were created using several different point

symbologies to distinguish between species.

Elasmobranch distributions were also mapped by generating fixed kernel density surfaces

in ArcMap 9.2 (ESRI 2005). Kernel density surface is a useful method to apply locational

observations to an animal’s home range (Worton 1989). Kernel density has also been used to

identify preferred habitat or “hotspot” locations of SAR listed marine mammals along the West

Trail Unit of PRNPR (Collyer et al 2007).

In this study, I generated a kernel for each observation point. Kernels can be thought of as

bumps (Silverman 1986) rising from the two-dimensional plane of the map (Figure 2). These

8


bumps are highest at the observation and decline in height, smoothly and symmetrically until it

meets the plane of the map at a specified distance from the observation (Figure 3). This distance

is termed the “search radius” in many GIS applications. The search radius affects how smooth or

flat the resulting surface appears. A larger search radius will create a smoother surface or a well-

defined mode. Although there are analytical methods designed to assist in the selection of an

appropriate search radius (Worton 1989, Silverman 1986, Seaman & Powell 1996), Beyer (2006)

suggests expert opinion and careful review of the results are the most important criteria.

9


Point

Line

Point + Line

Figure 2. Perspective view of the ArcMap quartic approximation of a Gaussian kernel for a single point, a single line and their sum

For each of these surfaces a search radius of 500 m was used. The lines shown are a 100 m regular square grid; note that the dimension of the radius of the point kernel and ½ the width of the line kernel is 500 m. The quartic kernel created from a point representing a single animal is shown at top. The quartic kernel created from a line representing a single animal (animal / scaling unit of line) is shown in the middle. Both of these kernels are probability densities; the volume under their surface integrates to 1. The sum of the two surfaces is shown at bottom; the volume of this surface equals 2. For the bottom surface to be a probability density it must be divided by 2 (the population value) used to create it.

2

2

2

2

^13),( ⎟⎟

⎠

⎞⎜⎜⎝

⎛−=

hr

hSNyxf

πfor hr ≤ and for 0),(

^=yxf hr >

Figure 3. Formula used to calculate the height of the kernel at each location on the plane. Where: f(x,y) is the value (height) of the surface at the evaluation point having the geographic co-ordinates (x,y), h is the search radius, r is the distance from the observation point to the evaluation point, N is the number of animals associated with the observation point (the population value) and S is a scaling factor often used to avoid rounding errors (Breyer 2006). When the S and N terms equal one, this formula is described as the quartic approximation of a bivariate Gaussian probability density function (O’Sullivan & Huber 2003).

10


To determine the “best” visual depiction of elasmobranch observations I varied the cell

size and search radius of the kernel density maps. A cell size should give an accurate visual

depiction and have smoother edges (more pixels) without being too small or too large (Beyer

2004). Three cell sizes were examined: 100 m, 500 m, and 100 m.

Huber (2003) emphasized that a search radius size should provide a logical and

meaningful kernel density map for the data and numerous radii should be examined to determine

the “best” size. Numerous search radii were explored ranging from 100 m to 10,000 m but only

four will be presented in this paper: 1000 m, 2500 m, 4000 m, and 5000 m. The final search

radius used in this study was selected based on the following criteria: 1) it revealed relatively

detailed patterns in the data, 2) it provided an error estimate for the elasmobranch location

entered and interpreted by the researcher, and 3) expert biological opinion considered that search

radius kernel could reasonably be used to model the area of activity of the animals.

Initially, I calculated the kernel density for the 2007 elasmobranch occurrence data. This

data was more reliable to identify areas of high use because it was collected on a regular basis

and the shorter time between the observation and reporting it to the researcher ensured more

accurate reports. Therefore cell size and search radii sizes were evaluated using this data. A

second kernel density map was calculated for all the current and historical elasmobranch

occurrence data in waters surrounding southern Vancouver Island. This kernel density surface

map used the cell and search radius size that was previously tested on the 2007 data.

3.3 Skate Egg case Surveys

Researchers and park wardens conducted egg case surveys in the Long Beach Unit of

PRNPR from February to May in 2007 and in February in 2008 (Table 1). No surveys were done

11


in the fall of 2007 because no egg cases were present on the beaches. One or two people did the

surveys by walking the high tide line of the beach. A handheld GPS unit (4 m positional

accuracy) recorded a survey track file (the area surveyed) and a waypoint location was taken for

every egg case found. Each egg case found was photographed, identified to species, and cut in

half to avoid double-counting. Voucher specimens were sent to Dr. David Ebert at Moss Landing

Marine Laboratories an expert in Northeast Pacific skate egg cases (Ebert and Davis 2007) for

species identification and confirmation.

Data was compiled and input into a Microsoft Excel database (\\PRP-WDNS-

Multi\Groups\Common\Jenn\sharks_and_rays\databases\Skate_eggcase_surveys.xls) and input

into the NatureServe Kestrel data management system (http://kestrel.natureserve.org). Lastly,

survey area and egg case location were mapped in ArcMap 9.2. By using a different symbol for

each egg case species I mapped the distribution of egg cases along the beaches within the Long

Beach unit of PRNPR. Survey areas were calculated with a 25-metre buffer on either side of the

track line, because it was the maximum distance a surveyor could distinguish an egg case on the

beach.

12

http://kestrel.natureserve.org/


4. Results

4.1 Current and Historical Elasmobranch Observations

In this study, a total of 284 elasmobranch observations were compiled from historical

records and current observations with 275 observations identified to species (Table 2). The

elasmobranch record locations ranged from the Aleutian Islands to Washington (Figure 4). More

specifically, 37 elasmobranch observations were recorded within the boundaries of PRNPR

(Table 3). The COSEWIC SAR-listed species observed include one endangered species (basking

shark), two special concern species (tope shark, bluntnose sixgill shark), one data deficient

species (blue shark), one not at risk species (big skate), and two species not assessed by

COSEWIC (spiny dogfish, salmon shark). Many observations made within PRNPR were

carcasses washed up on the beaches, but indicate that the marine waters within and outside

national park boundaries are being utilized by these species. In the waters surrounding GINPR

32 elasmobranch observations were recorded (Table 3). The RBCM collection records provided

all the records for GINPR and were only historical records. The records for the waters

surrounding GINPR consisted of three skate species listed as not at risk by COSEWIC (big,

longnose and sandpaper skates) and the spiny dogfish currently not assessed by COSEWIC.

13


Table 2. Summary of elasmobranch species recorded during this study and their known distribution in the northeast Pacific.

Species Common name Distribution # of recordsAlopias vulpinus Thresher shark Southeast Alaska to Chile 2 Amblyraja badia Broad skate BC to Panama 2 Bathyraja abyssicola Deepsea skate Aleutian Islands to southern California 1 Bathyraja aleutica Aleutian skate Bering Sea to Gulf of Alaska 4 Bathyraja interrupta Sandpaper skate Bering Sea to southern California 44 Bathyraja maculata Whiteblotched skate Bering Sea 1 Bathyraja minispinosa Whitebrow skate Bering Sea 1 Bathyraja parmifera Alaska skate Bering Sea to Gulf of Alaska 5 Bathyraja trachura Roughtail skate Bering Sea to Baja California 6 Carcharodon carcharias Great white shark Gulf of Alaska to Gulf of California 9 Cetorhinus maximus Basking shark Gulf of Alaska to Gulf of California 8 Galeorhinus galeus Tope shark Northern BC to Gulf of California 18 Hexanchus griseus Bluntnose sixgill shark Aleutian Islands to California 10 Isurus oxyrinchus Shortfin mako Aleutian Islands to Chile 2 Lamna ditropis Salmon shark Bering Sea to Baja California 16 Notorynchus cepedianus Broadnose sevengill shark Northern BC to Gulf of California 3 Prionace glauca Blue shark Gulf of Alaska to Chile 46 Pteroplatytrygon violacea Pelagic stingray BC to Chile 1 Raja binoculata Big skate Bering Sea to Baja California 22 Raja rhina Longnose skate Bering Sea to Baja California 20 Raja stellulata Starry skate Bering Sea to Baja California 1 Somniosus pacificus Pacific sleeper shark Bering Sea to Baja California 2 Squalus acanthias Spiny dogfish Bering Sea to Gulf of California 49 Torpedo californica Pacific electric ray Northern BC to Baja California 2 Total # of records 275

14

Figure 4. Distribution of all elasmobranch observations.


Table 3. All elasmobranch observations that occurred within the boundaries of PRNPR and in waters adjacent to GINPR.

Location

Species

COSEWIC assessment

Date

# of records

Pacific Rim National Park Reserve Grice bay Spiny dogfish Not assessed Aug 11, 2002 10 Big skate Not at risk May 25, 2005 1 Long beach Tope shark Special concern Oct 21, 1990 1 Tope shark Special concern Oct 22, 2004 1 Salmon shark Not assessed July 17, 2005 1 Basking shark Endangered Aug 16, 2006 1 Tope shark Special concern Oct 6, 2007 1 Combers beach Tope shark Special concern Nov 20, 2000 1 Tope shark Special concern Oct 5, 2004 1 Big skate Not at risk Aug 29, 2007 1 Wickaninnish beach Salmon shark Not assessed 1999 1 Big skate Not at risk Jun 3, 2006 1 Florencia bay Bluntnose sixgill shark Special concern Feb 13, 1992 1 Spiny dogfish Not at risk Aug 3, 2007 1 Spiny dogfish Not at risk Sept 13, 2007 1 Broken group Spiny dogfish Not at risk Jun 30, 1973 6 islands Spiny dogfish Not at risk July 2, 2007 1 Pachena bay Tope shark Special concern Oct 4, 2007 1 Tsusiat Salmon shark Not assessed Aug 14, 2006 1 Blue shark Data deficient July 7, 2006 1 Carmanah Salmon shark Not assessed June 27, 2007 1 Salmon shark Not assessed Aug 23, 2007 1 Big skate Not at risk Sept 2, 2007 1 Gulf Islands National Park Reserve Fulford harbour Big skate Not at risk Feb 2, 1965 3 Longnose skate Not at risk Feb 2, 1965 1 Satellite channel Sandpaper skate Not at risk Feb 26, 1941 2 Sandpaper skate Not at risk May 15, 1978 2 Longnose skate Not at risk Oct 3, 1978 1 Spiny dogfish Not at risk Oct 3, 1978 2 Sandpaper skate Not at risk Jan 29, 1979 3 Saltspring island, Sandpaper skate Not at risk Oct 26, 1978 4 beaver point Sandpaper skate Not at risk Jan 29, 1979 2 Portland island Sandpaper skate Not at risk Oct 26, 1978 1 Swanson channel Spiny dogfish Not assessed Oct 3, 1978 2 Sandpaper skate Not at risk Jan 29, 1979 1 Prevost passage Sandpaper skate Not at risk Oct 26, 1978 3 Longnose skate Not at risk Oct 26, 1978 3 Longnose skate Not at risk Jan 29, 1979 1 James island Longnose skate Not at risk Oct 26, 1978 1

16


Individual species distribution maps were prepared for nine common elasmobranch

species that occurred within and adjacent to the boundaries of PRNPR and GINPR. A total of 19

big skates were recorded for southern Vancouver Island (Figure 5). In this study, a few

observations were recorded north of Vancouver Island from the RBCM records, but otherwise

that area was not surveyed. Therefore, three additional big skate observations made in the

southern Queen Charlotte Islands in Gowgaia bay on Moresby Island were not shown in the map.

The five big skate observations made in the southern Gulf Islands are from historical records

collected by the RBCM. Overall, big skates are frequently observed and caught in waters

adjacent to PRNPR and carcasses often wash up on beaches within the national park.

A total of eight historical basking shark records were recorded for the west coast of

Vancouver Island (Figure 6). Six observations were recorded in 1998-99, and two observations

occurred in 2005 and 2006. However, inexperienced observers reported the 2005 and 2006

observations and therefore species identity remains unconfirmed. These two observations were

still included in the database and map with appropriate comments on confidence level.

Blue sharks were the most frequently reported species by sportfishers fishing in waters

off Vancouver Island. A total of 45 blue sharks were reported from 1994 to 2007, with 29 of

these observations made in 2007 (Figure 7).

Bluntnose sixgill sharks and broadnose sevengill sharks were mapped together because

there were fewer observations (Figure 8). A total of ten bluntnose sixgill sharks were reported

between 1941 and 2007, with six observations occurring along the west coast of Vancouver

Island and four located in the southern Gulf Islands. In addition, sixgill sharks are known to

frequent Tyler Rock in Barkley Sound. However exact dates and numbers were not collected

during this study and consequently the observations were not included in the database or maps. A

17


total of three observations of broadnose sevengill sharks were made on Swiftsure bank off the

West Coast Trail in 2006 and 2007. Confirmation of the broadnose sevengill sighting in 2006

was made from the original photograph (Appendix 3).

A total of nine great white shark observations were recorded along the west coast of

Vancouver Island from 1963 to 2007 (Figure 9). However, only four of these observations were

confirmed through photographs and expert opinion.

A total of 15 salmon shark records were mapped from records collected from 1949 to

2007 (Figure 10). The RBCM recorded the 1949 observation that was the only record that

occurred in the southern Gulf Islands. In addition, all observations that occurred within the

PRNPR boundaries were beached juvenile salmon sharks.

Forty-nine spiny dogfish sharks observations were recorded from 1939 to 2007 (Figure

11). The historical records were compiled from the RBCM and ranged from the southern Gulf

Islands to the Broken Group Islands within PRNPR. Sportfishers made most of the observations

in 2007 by either catching or observing spiny dogfish while they were fishing for other fish.

A total of 17 tope shark locations were recorded from observations made from 1947 to

2007 (Figure 12). The RBCM recorded two historical records made in 1947 that occurred in the

southern waters of Vancouver Island. In addition, the majority of the observations made within

PRNPR were from dead tope sharks washing up on beaches within the national park.

18


Figure 5. The recorded big skate observations from 1887 to 2007.

Figure 6. The 8 recorded basking shark observations from 1998 to 2006 (6 confirmed observations).

19


Figure 7. The 45 recorded blue shark observations from 1994 to 2007.

Figure 8. The 10 bluntnose sixgill shark and 3 broadnose sevengill shark observations from 1941 to 2007.

20


Figure 9. The 9 great white shark observations from 1963 to 2007 (4 confirmed observations).

Figure 10. The 15 salmon shark observations from 1949 to 2007.

21


Figure 11. The 49 spiny dogfish shark observations from 1939 to 2007.

Figure 12. The 17 tope shark observations from 1947 to 2007.

22


Overall, in 2007, 84 elasmobranch observations were recorded in waters along the west

coast of Vancouver Island and consisted of eight species and one unidentified shark species

(Figure 13). The observations confirmed by photographs include a big skate on Combers beach,

a spiny dogfish on Florencia bay, two salmon sharks beached near Carmanah lighthouse on the

West Coast Trail, one tope shark on Long Beach and one tope shark on Pachena bay (Appendix

3). The surveyor identified all other observations from the observer or through a detailed

description.

In 2007, the number of elasmobranch sightings was highest from July to September

(Figure 14). Blue sharks were sighted most frequently in August and spiny dogfish had the

highest number of sighting in September. All other species were observed at relatively low

numbers from April to November.

Figure 13. All elasmobranch observations made in 2007.

23


0

2

4

6

8

10

12

14

16

18

20

Apr May June July Aug Sept Oct Nov

Num

ber o

f ind

ivid

uals

Big skateBlue sharkBluntnose sixgillBroadnose sevengillGreat white sharkSalmon sharkSpiny dogfishTope shark

Figure 14. Number of individual elasmobranch species observed each month in 2007.

24


4.2 Kernel Density Surface Maps for Elasmobranch Observations

Kernel density surfaces were generated from elasmobranch observations recorded in

2007 using three different cell sizes (1000 m, 500 m, and 100 m) (Figure 15). A cell size of

100m provided the best visualization of the data at the geographical scale used in this analysis.

The second step explored the best search radius size and the four search radii sizes

explored include: 1000m, 2500m, 4000m, and 5000m (Figure 16). The search radius that

provided the best data resolution and adequately addressed the mobility of the animals was

4000m (Figure 17).

Overall, the highest density of elasmobranch observations occurred in offshore waters on

La Perouse and Swiftsure banks (Figure 17). In nearshore waters, areas of higher elasmobranch

densities occurred off Nitinat lake and Carmanah lighthouse along the West Coast Trail. A

smaller high density area occurred in the rocky shores adjacent to Amphitrite lighthouse and

lastly, the most northerly high density area occurred along Chesterman’s beach. The only high

density area that occurred within the boundaries of PRNPR was along the West Coast Trail just

north of Carmanah lighthouse.

Kernel density surface was also examined for all elasmobranch observations recorded in

the southern waters of Vancouver Island (Figure 18). The highest density of elasmobranchs in

GINPR occurred in the waters surrounding Portland Island. Off the west coast of Vancouver

Island areas along La Perouse and Swiftsure banks had the highest densities of elasmobranches.

High elasmobranch density areas within PRNPR include Nitinat to Caramanh along the WCT,

the southeast corner of the BGI, along Long Beach and in Grice Bay. The rocky outer shorelines

near Ucluelet and Chesterman’s Beach near Tofino also had high elasmobranch densities.

25


Figure 15. Kernel density surface of all elasmobranch observations recorded in 2007 using three different cell sizes (1000 m, 500 m, and 100 m).

26


Figure 16. Kernel density surface of all elasmobranch observations recorded in 2007 using four different search radii (1000 m, 2500 m, 4000 m, 5000 m).

27


Figure 17. Kernel density surface of all elasmobranch observations recorded in 2007 using four different 4000 m search radius and 100 m cell size with geographic locations labelled.

Figure 18. Kernel density surface of all elasmobranch observations from all years combined that occurred in the southern waters of Vancouver Island with geographic locals labelled.

28


4.3 Skate Egg case Surveys

Eight skate egg case surveys were done in the Long Beach Unit of PRNPR. From

February to December in 2007, five surveys were done from Long beach north to outside the

national boundaries on Fletchers beach (Figure 19). Three surveys were done from Long beach

north to South beach from January to February 2008 (Figure 20).

Three species (big skate, longnose skate and spotted ratfish) were identified from all the

egg cases observed (Figure 21). Survey 1, done on February 15, 2007 along Long beach north

had a total of 20 big skate egg cases, 51 longnose skate egg cases and two ratfish egg cases

(Figure 22). Survey 2, also done along Long beach north but on April 27, 2007, had a total of 9

big skate egg cases, 28 longnose skate egg cases, and one ratfish (Hydrolagus colliei) egg case

(Figure 22). Survey 3 done from Long beach to Combers beach on May 2, 2007 had only two

egg cases found, one big skate and one longnose skate (Figure 22). Survey 4 done on May 2,

2007 along Wickaninnish beach had no egg cases. Survey 5 was the last survey done in 2007 on

December 9th on Fletchers beach and one big skate egg case was found (Figure 22).

In 2008, the first survey, Survey 6, was done on January 18th and 14 big skate egg cases

and four longnose skate egg cases were found (Figure 23). Surveys 7 and 8 were both done on

February 4th and the Survey 7 along South beach found two longnose skate egg cases and Survey

8 from Long beach to Combers beach found one longnose egg case (Figure 23).

29


Figure 19. Skate egg case survey areas for the five surveys conducted from February to December in 2007.

30


Figure 20. Skate egg case survey areas for the three surveys conducted from January to February in 2008.

31


Longnose skate

Spotted ratfish

Big skate

Figure 21. Three egg case species found and identified during the egg case surveys.

32


Survey 1 Long beach north, February 15, 2007

Survey 2 Long beach north, April 27, 2007

Survey 3 Long beach, May 2, 2007

Survey 5 Fletchers beach, December 9, 2007

Figure 22. Survey areas and skate egg case species and locations for surveys conducted in 2007. Survey 4 was not included because there were no egg cases found.

33


Survey 6 Long beach north, January 18, 2008

Survey 7 South beach, February 4, 2008

Survey 8 Long beach, February 4, 2008

Figure 23. Survey areas and skate egg case species and locations for surveys conducted in 2008.

34


5. Discussion

The Committee on the Status of Endangered Species (COSEWIC) assessed nine

elasmobranch species with ranges extending into the marine waters adjacent to and within

Pacific Rim National Park Reserve (PRNPR). COSEWIC listed basking shark as endangered,

the bluntnose sixgill and tope shark were listed as special concern, the brown cat shark, blue

shark and great white shark were listed as data deficient, and the big, longnose and sandpaper

skate species were listed as not at risk. In this study, historical and current locations were

recorded for all of these species, except the brown cat shark (Figures 5 to 11). Seven of the nine

species had records that occurred in waters within and adjacent to PRNPR, records for brown cat

shark and the sandpaper skate were absent. However, the Royal British Columbia Museum

(RBCM) did have historical records for all three skate species, including the sandpaper skate in

waters surrounding Gulf Islands National Park Reserve (GINPR). In addition, RBCM also had

bluntnose sixgill and tope sharks records for GINPR.

Historical elasmobranch locations were most easily accessible in local areas through

direct contact with individuals living in the community. The same was true for current

elasmobranch observations. Local sportfisher surveys provided the more information on current

elasmobranch locations than any other method employed. Consequently, to obtain both

behavioural and current location information on elasmobranchs I recommend continuing

interview style surveys with local residents, specifically sportfishers working on the water.

Posted notices with email and phone numbers were good tools to raise awareness of the project

and generated around twenty individual inquiries about the project. However, the majority of the

current observations were recorded during surveys and notices provided a good project

introduction during these surveys.

35


Interview data accuracy was lower than direct observations because exact location

information and species confirmation was not always available. Therefore, a knowledgeable and

experienced interviewer who asked sufficient and descriptive questions was essential and repeat

interviews with the same individuals also created a rapport between the surveyor and the

interviewee. Sportfisher surveys should also be done at different times of the years to ensure

inclusion of all species observations (Figure 14). The fishing season occurs roughly between

May and September with a higher number of fishers and sharks occurring in July and August.

Consequently, surveys should be done once a month in May, June and September and weekly to

biweekly in July and August.

In 2007 nine elasmobranch species were recorded in waters adjacent to and within

PRNPR (Figure 13). Of these nine species, five were assessed by COSEWIC including the big

skate, blue shark, great white shark, bluntnose sixgill shark, and tope shark. A multi-species

analysis of elasmobranch densities showed the highest number of elasmobranch observations in

2007 occurred on La Perouse and Swiftsure banks (Figure 17). These observations were made

mainly by sportfishers and therefore occur in areas where they also fish. Areas where halibut are

fished were also areas where big skates were caught and areas where salmon trolling occurred

are also areas where shark species were found. This is partly a reflection of observer location

bias. However, all of these species: salmon, sharks, halibut and skates, are usually seen in these

areas actively feeding and therefore these location may also reflect areas of high prey densities.

Overall, sportfisher provided a valuable source of elasmobranch location data and future research

could train sportfisher guides on species identification and recording precise location

information. In addition, sportfishers could also be trained to report observations of other marine

36


SAR listed species such as Northern and Southern resident killer whales, leatherback turtles, sea

otters, and humpback whales.

A total of eight skate egg case surveys were also conducted in 2007 and 2008 in the Long

Beach unit of PRNPR (Figures 18 and 19). Overall, big and longnose skate egg cases were found

most abundantly on the beaches, as well as few spotted ratfish egg cases (Figure 21). Although

other skate species are known to occur along the west coast of Vancouver Island, their egg cases

were not found during these surveys. However, the smaller longnose skate egg cases can be very

difficult to distinguish between other local skate species (Ebert and Davis 2007). Consequently,

all egg cases were photographed and any egg case about identity of which I was uncertain, was

sent to Dr. David Ebert at the Pacific Shark Research Center in Moss Landing, California. Dr.

Ebert confirmed species ID; in this case that all the cases belonged to the longnose skate (Raja

rhina). Therefore, a total of two skate species were found during this study.

Big skates deposit eggs throughout the year and longnose skates do not have a known

breeding season (Ebert 2003). However, on Long beach skate egg cases are found most

frequently from January to May and Long beach north had the highest number of egg cases

(Figures 21 and 22). Therefore, if time is limited an effective skate egg case monitoring program

should occur in February along Long beach north. Additionally, skate egg case surveys are cost

effective and a relatively straightforward method to collect data on skate species that exist in the

coastal waters of PRNPR.

Incorporating community knowledge and Aboriginal traditional knowledge has also been

identified as an important component of the COSEWIC assessment process (COSEWIC 2008).

Future studies should obtain valuable elasmobranch information through First Nations

Traditional Ecological Knowledge (TEK). Vancouver Island has a rich and diverse First Nations

37


community whose connection with the surrounding marine environment is equally as rich and

diverse. Interviews with First Nations elders would add to the understanding and history of

elasmobranch species surrounding Vancouver Island, including PRNPR and GINPR. Additional

local ecological knowledge could also be collected from past newspaper articles and fishing

magazines. Scott Wallace and Brian Gisborne used this type of information to recount historical

basking shark abundance and distribution data (Wallace and Gisborne 2006). Sharks tend to be

newsworthy items and local community newspapers could add species-specific historical

abundance and distribution data of SAR listed elasmobranch species.

The involvement of local community members in this project facilitated the need to

communicate project updates and results to ensure project support and provide a foundation on

which to build further relationships. Specifically, I contributed to PRNPR’s community updates

column in the local Westerly newspaper. Three different articles were written on different

components of the project in February, August and September 2007. Articles on the project were

also written for the spring 2007 and 2008 Tour Operator Bulletin for PRNPR and the Coastal BC

Field Unit 2007 fall Tidelines newsletter. Also, I gave two ten-minute radio interviews about the

project to CBC radio for “On the Island” with Gregor Craigie on September 6, 2007 on sharks

and February 15, 2008 on skates. Communication and feedback with local communities was an

essential component of this project integral for relationship building and continued engagement

with the local community for this and future projects.

38


6. Future Recommendations

• Work with local First Nations communities to compile historical records of sharks and skates

from First Nations Traditional Ecological Knowledge

• Develop and deliver a training workshop for sportfishing guides on elasmobranch

identification and reporting

• Interview-style surveys on local community docks were the most effective method to collect

information on elasmobranch sightings

• Continue to conduct skate egg case surveys in February in Long beach north to get a

snapshot of skate species diversity and relative abundance in the waters of PRNPR

• Develop a pamphlet that highlights sharks and skates found at PRNPR and their ecological

importance to increase public awareness about this group and Species at Risk

• Employ a variety of communication tools to report back to the local community on project

results and updates including local newspaper articles, radio interviews, internet websites,

community presentations, make the final report available to interested community members

39


7. Literature cited Baum, J. K., R. A. Myers, D. G. Kehler, B. Worm, S. J. Harley and P. A. Doherty (2003) Collapse and Conservation of Shark Population in the Northwest Atlantic. Science 299:389-392. Beyer H. (2006) Hawth’s Tools on-line help documentation. Beyer, H. (2005) ArcGIS Desktop Discussion Conference. http://forums.esri.com/Thread.asp?c=93&f=995&t=160417#469236 Collyer, M., J. L. Yakimishyn and H. Holmes (2007) Integration of Habitat Needs of Species at Risk in Pacific Rim National Park Reserve of Canada, Report One; Compiling and Mapping Observations. SARRAEF COSEWIC (February 2008) About COSEWIC, Incorporating Community Knowledge into COSEWIC Assessment Process. http://www.cosewic.gc.ca/eng/sct6/sct6_7_e.cfm COSEWIC (February 2007) COSEWIC Status Reports in Preparation. http://www.cosewic.gc.ca/eng/sct2/sct2_4_e.cfm CITES (February 2007) Appendices I, II and III. http://www.cites.org/eng/app/appendices.shtml Ebert, D. A. and C. D. Davis (2007) Description of skate egg cases (Chondrichthyes: Rajiformes: Rajoidei) from the eastern North Pacific. Zootaxa 1393:1-18. Ebert, D. A. (2003) Sharks, Rays, and Chimaeras of California. Los Angeles: University of California Press ESRI (2005) ArcGIS v 9.1 desktop GIS Mapping software. http://www.esri.com/software/arcgis/about/desktop.html Huber, W. (2003) ArcGIS Desktop Discussion Conference. http://forums.esri.com/Thread.asp?c=93&f=995&t=97678#272387 IUCN (February 2007) 2006 IUCN Red List of Threatened Species. http://www.iucnredlist.org/ FishBase (February 2007) http://www.fishbase.org/search.php Myers, R. A., J. K. Baum, T. D. Shepherd, S. P. Powers and C. H. Peterson (2007) Cascading effects of the loss of apex predatory sharks from a coastal ocean. Science 315:1846-1850. O'Sullivan, D. and W. Huber (2003) Algorithm for kernel density estimation in Spatial Analyst. ESRI ArcGIS Desktop - Extension - Spatial Analyst Discussion Forum. http://forums.esri.com/Thread.asp?c=93&f=995&t=98735#277890 Seaman, D. E., and R. A. Powell (1996) An evaluation of the accuracy of kernel density estimators for home range analysis. Ecology 77: 2075–2085.

40

http://forums.esri.com/Thread.asp?c=93&f=995&t=160417#469236

http://www.cosewic.gc.ca/eng/sct2/sct2_4_e.cfm

http://www.cites.org/eng/app/appendices.shtml

http://www.esri.com/software/arcgis/about/desktop.html

http://www.iucnredlist.org/

http://www.fishbase.org/search.php

http://forums.esri.com/Thread.asp?c=93&f=995&t=98735#277890


Silverman, B. W. (1986). Density Estimation for Statistics and Data Analysis. London: Chapman and Hall. Wallace, S. (2007) Personal Communication Wallace S. and B. Gisborne (2006) Basking Sharks: The Slaughter of BC’S Gentle Giants. Vancouver: New Star Books Worton, B. J. (1989) Kernel Methods for Estimating the Utilization Distribution in Home-Range Studies. Ecology 70:164-168.

41


Appendix 1 - Report a Shark Skate or Ray Poster

42


Report a Shark, Skate or Ray

Sharks, skates and rays are cartilaginous marine fish that inhabit coastal waters of British Columbia. Knowledge of these species is very limited because they are highly mobile, elusive and long-lived. We hope to fill in knowledge gaps of this group of marine fish and you can help! If you catch a shark or skate while fishing or see one washed in on a beach we want to hear from you. Here are some steps you can take quickly and with little equipment. Note if a beached shark is alive or shows any responsiveness - do NOT touch it. Take a photo if you can and report it to the email address or phone number below. If you happen to catch the shark while fishing please take a photo and release the animal alive. • Essential information:

o Record date, time and location including GPS coordinates (if possible) o Length from tip of nose to tip of tail (use your foot length if no equipment is

available) o Sex – males have claspers o Any marks, injuries or fishing gear that suggests how the animal may have died

• Photograph: o Whole animal, preferably the SIDE view (include hand or foot for scale) o Underside of the head and under the pectoral fins o Underside of the pelvic fins (verifies shark’s sex) o Teeth, close-up (verifies species identification)

Please contact Jennifer Yakimishyn or Tanya Dowdall at the Pacific Rim National Park Warden Office to report your finding.

Report a Shark, Skate or Ray:

Phone: (250) 726-7165 ext. 224 Email: [email protected]

Side photo of a tope shark found beached on Long Beach in Pacific Rim National Park Reserve

Dorsal photo of a big skate found beached in Bamfield Inlet

43


Appendix 2 - Elasmobranch Survey Form

44


Date and location of survey: Reporting person/ Contact info

Date/Time Location Lat/Long Habitat

Species Photo

Description (colour, size, marks, sex, age)

Behaviour Comments

45


Appendix 3 - Photographs of Elasmobranch Records

46


Broadnose sevengill shark caught in 2006 by sportfishers on the northwest corner of Swiftsure bank off the West Coast Trail of PRNPR. (Photo credit: Mark Banning)

47


Big skate washed up on Combers beach on August 29, 2007. (Photo credit: Jennifer Yakimishyn)

Spiny dogfish washed up in Florencia bay on September 13, 2007. (Photo credit: Billy Wilton)

48


Juvenile salmon shark washed up on the West Coast Trail near Carmanah lighthouse on June 27, 2007. (Photo credit: Natalie Verrier)

Juvenile salmon shark washed up on the West Coast Trail near Carmanah lighthouse on August 23, 2007. (Photo credit: Robin Clugston)

49


Tope shark washed up on Long Beach on October 6, 2007. (Photo credit: Ben Alderman)

Tope shark washed up on Pachena bay on October 4, 2007. (Photo credit: Kyle Nguyen)

50

prnpr shark skate inventory

Documents

confirmed observations

salmon shark observations

tope shark observations

great white shark observations

shark skate

list of figures figure

elasmobranch survey

kernel density surface