Distribution and Migration of Sonic-Tagged Sturgeon

DISTRIBUTION AND MIGRATION OF SONIC-TAGGED STURGEON

WITH REGARDS TO OVERWINTERING HABITAT

IN THE LOWER FRASER RIVER, 2011-12

By:

Sara Ghilarducci

Mike Reeve

BRITISH COLUMBIA INSTITUTE OF TECHNOLOGY

FISH, WILDLIFE, AND RECREATION 2011/2012

DISTRIBUTION AND MIGRATION OF SONIC-TAGGED STURGEON

WITH REGARDS TO OVERWINTERING HABITAT

IN THE LOWER FRASER RIVER, 2011-12

By:

Sara Ghilarducci

Mike Reeve

A REPORT SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DIPLOMA OF TECHNOLOGY

FISH, WILDLIFE & RECREATION MANAGEMENT RENEWABLE RESOURCES TECHNOLOGY SCHOOL OF CONSTRUCTION AND THE ENVIRONMENT

______Supervisor

______Program Head

BRITISH COLUMBIA INSTITUTE OF TECHNOLOGY

May, 2012

Abstract

A previously sonic-tagged sub-population of 110 white sturgeon, (Acipenser transmontanus), was tracked using mobile tracking equipment from October 2011 to February 2012. The study was performed on the Lower Fraser River, British Columbia, Canada, from the Port Mann Bridge downstream to the confluence of the Sumas River upstream, including the Lower Pitt River from its confluence with the Fraser River up to Grant Narrows Regional Park at the outlet of Pitt Lake. The study area was broken into 4 reaches to accommodate what could be reasonably assessed on a given day of tracking. A 16’ fiberglass boat mounted with a Vemco VR 100 sonic-tracking unit was utilized to track the sonic-tagged sturgeon, which were previously implanted with the acoustic tags.

The aim of this study was to conduct sampling once each for all four of the study reaches during both the fall (pre-winter) and winter (overwinter) periods to try and identify distribution and seasonal shifts in habitat usage. Additionally, water temperatures, depth at detection and flow rates were recorded for each of the sample days. Water temperatures ranged from a low of 0ᵒ Celsius to a high of 8ᵒ Celsius. Depth at detection ranged from ~6-30 meters. Flow rates ranged from a high of ~2100 m3/s in October 2011, coinciding with fall rains, to a low of ~850m3/s in January 2012, coinciding with freezing temperatures.

The main findings of this study include: A total of 18 individuals from the original 110 tagged sturgeon were detected in the study area at some point, with daily detections ranging from 0-10 individuals. The sturgeon that were detected were scattered throughout the study area with the highest concentration observed on the Lower Pitt River, (rkm P11 Ernie’s hole). Of the 18 individuals detected, two were detected in both study periods. Movements of these sturgeon varied from <1 km to >37 km with 61% moving >5 km over the course of the four years since initially tagged. Although generally adults tended to move less than juveniles, there was no significant difference in distance travelled as it related to size of the sturgeon.

From the data that we gathered during our study, it appears that sturgeon may prefer a variety of sites in the study area, with rkm P11 being preferred. This may be a preferred year round location for all size classes of fish as the data suggests. Replication of this study in future years is recommended to gain a clearer picture of distribution and migration of these fish.

Table of Contents

Abstract ...... 1 Table of Contents ...... 2 List of Figures ...... 3 List of Tables ...... 4 Acknowledgements ...... 5 1.0 Introduction ...... 6 2.0 Purpose and Objectives ...... 9 3.0 Study Area ...... 9 3.1 Site Description ...... 9 3.2.1 Gravel Reach of the Lower Fraser River ...... 9 3.2.2 Sand Reach of the Lower Fraser River ...... 10 3.2.3 Project Study Areas ...... 10 4.0 Methods...... 15 5.0 Results ...... 17 5.1 Overall Total Detections ...... 17 5.2 Pre-winter and Overwinter Distribution and Movements of Sub-population of 110 tagged White Sturgeon in the Lower Fraser River, B.C...... 19 6.0 Discussion ...... 23 6.1 Distribution of Detected Sturgeon ...... 23 6.2 Habitat Utilization by Sturgeon ...... 24 7.0 Recommendations & Conclusions ...... 24 References ...... 26 Appendices ...... 27 APPENDIX A ...... 27 APPENDIX B ...... 29 APPENDIX C ...... 32 APPENDIX D ...... 34 APPENDIX E ...... 46 APPENDIX F...... 51

List of Figures

Figure 1. Map of British Columbia with an outline of the entire length of the Fraser River highlighted in red...... 7 Figure 2. Study area of the 2011/2012 sonic tracking of sturgeon migration, highlighted in blue...... 8 Figure 3. Study Reach 1- Port Mann Bridge upstream to Golden Ears Bridge including the Lower Pitt River upstream to the Pitt River Bridge...... 11 Figure 4. Study Reach 2- Encompasses a large portion of the Lower Pitt River starting at the Pitt River Bridge upstream to the outflow of Pitt Lake...... 12 Figure 5. Study Reach 3- Golden Ears Bridge upstream to Mission Bridge including Derby Reach and Matsqui channel...... 13 Figure 6. Study Reach 4- Mission Bridge upstream to confluence of the Sumas River and the Fraser River...... 14 Figure 8. 16' Hourston fiberglass boat used in the study of white sturgeon on the Lower Fraser River .... 15 Figure 9. This figure shows the approximate method of covering a given reach crossing from bank to bank at 45 degree angles at a slow speed to detect tags of tagged sturgeon...... 16 Figure 10. Graph showing detections broken down by size class (< 1meter, > 1meter), and number of individuals detected, whether new (capture) or previous (recapture)...... 18 Figure 11. Graph showing size range of individuals broken down by new detections (2011-12) and previous detections (2009-10)...... 19 Figure 12. Graph showing total distance travelled by size class (<1 m, >1m)...... 21 Figure 13. Graph showing average distance travelled by size class (<1 m,>1m)...... 21 Figure 14. Scatterplot showing individual detections by size and distance traveled with a general trend line inserted...... 22 Figure 15. Graph showing average distance travelled for all sizes by original tagging location, Fraser or Pitt, (CI 9.7 and 6.1 respectively)...... 22

List of Tables

Table 1. Number of detections of white sturgeon broken down by reach showing the total detections for the entire study area ...... 17 Table 2. Pre-winter, (Oct 26th to Nov 16th 2011) detections of white sturgeon in the Lower Fraser River, BC ...... 20 Table 3. Overwinter, (Jan 18th to Feb 4th 2012) detections of white sturgeon in the Lower Fraser River, BC ...... 20

Acknowledgements

There are many groups and individuals we would like to thank for their support and contribution to this project. Thank you to the British Columbia Institute of Technology and the Rivers Institute at BCIT for their financial support and use of their boat and equipment. This study would also not have been possible without the use of the tracking equipment on loan from Jonathan Thar of the Vancouver Aquarium’s Pacific Ocean Shelf Tracking program (POST). Our Supervisor, Dr. Marvin L. Rosenau has been an incredible source of knowledge, guidance and support throughout the project as has Troy Nelson, Director of Science with the Fraser River Sturgeon Conservation Society (FRSCS). Additionally, we would like to extend our sincere gratitude to LGL Ltd. for their help and support. Paul Neufeld, who was part of a team that conducted the original study in 2009-10 has been available for consultation and provided invaluable insight and experience with enthusiasm as well as equipment necessary for this projects success. We would also like to thank Bob Gunn, Program Head of the Fish, Wildlife and Recreation program for his time and support with this project and as well, all my fellow classmates and colleagues in the FWR program, without whom, this project may not have seen completion. Between actual data collection and report editing, I owe a huge debt of gratitude to them for their help and support. Finally, but also first and foremost, I would like to thank and give tribute to Sara Ghilarducci. Sara passed away suddenly in November this past year, she was an integral part of this project and had an enthusiasm for these fish and life in general that was absolutely captivating and unequaled, she will be dearly missed. This project is dedicated in her memory.

1.0 Introduction

Historically little has been known about Fraser River (Fig. 1) white sturgeon (Acipenser transmontanus). Late in the nineteenth and early in the twentieth century white sturgeon in this stream were commercially fished to near-extinction (Glavin, 1994). Over fishing, coupled with habitat loss due to development, have been suggested as the main causes for the population declines (Rosenau et al. 2007, Nelson et al. 2006).

The province of British Columbia has a responsibility and a long-standing interest in the conservation, protection, management, and assessment of Fraser River white sturgeon (LGL Ltd, 2004). The Fraser River Conservation Society (FRSCS), a not-for-profit organization founded to protect and preserve this threatened species, has been instrumental in initiating research to better understand population dynamics and habitat use by the fish. In early 2008, a study was initiated with FRSCS to track white sturgeon in the lower Fraser and Pitt Rivers and the design included implanting a sub-population of these fish with sonic tags (Robichaud, 2010).

In 2008, 110 white sturgeon were tagged through a concerted volunteer catch-tag and release program that saw these fish implanted with sonic tags in late summer and fall of that year (Robichaud, 2010). This study involved identifying two key areas in the lower Fraser and Pitt rivers where fish were known to congregate (Neufeld et al. 2010) (Fig.2).

The focus of the study was to try and understand the movements, overwintering habits and habitat-use of these fish and this study aimed to identify potential impacts of bridge construction in the lower watershed (e.g., Pitt River bridge expansion). Considerable information has been determined as a result of this work in respect to the behavior of these fish (Nelson et al. 1999- 2004, Nelson et al. 2008, Neufeld et al. 2010). The tagged sub-population of 110 white sturgeon were only able to be monitored via stationary tracking receivers situated at various locations in the lower Fraser River.

Figure 1. Map of British Columbia with an outline of the entire length of the Fraser River highlighted in red. Included is an inset of the Fraser River floodplain which shows the study area of the 2011/2012 sonic tracking study of sturgeon migration which is highlighted in orange. The study area extends from the upstream end of the Lower Pitt River and from the Port Mann Bridge on the Fraser River to the confluence of the Sumas River.

Although stationary-tracking equipment is located at various locations throughout the Lower Fraser River and Pitt River over the last several years, little was known about the sturgeon’s movements in-between and outside-of the range of these static transceivers. A mobile-tracking program was initiated in 2008-2009, in conjunction with the FRSCS, by the British Columbia Institute of Technology (BCIT) Fish, Wildlife and Recreation (FWR) program to further our understanding of these tagged fish.

With the assistance of the FRSCS, and the Pacific Ocean Shelf Tracking Program (POST), use of a mobile tracking unit was made available to the FWR Program and tracking was conducted in four “reaches” between the Port Mann Bridge and the Sumas River on the Fraser River, and up to Pitt Lake on the Pitt River (Neufeld et al. 2010). (Fig. 2)

Figure 2. Study area of the 2011/2012 sonic tracking of sturgeon migration, highlighted in blue. The two locations where 110 sturgeon were tagged are shown by the orange squares with one tagging location located within the Pitt River northwest of Sturgeon Slough and the second tagging location east of the Port Mann Bridge and west of Douglas Island.

Movements of this selected group of previously-caught and tagged sturgeon were monitored on an ongoing basis throughout the months of November and December in 2009 and January and February of 2010 (Neufeld et al. 2010). Our study in 2011-2012 was a continuation of this earlier work.

The primary results of the 2009-10 white sturgeon monitoring study were that individual sonic- tagged white sturgeon were detected throughout the study area with main concentrations in the lower Pitt River, the Douglas Island area and at the outlet of the Stave River; except for the mouth of the Stave, these are all locations near where the original tagging occurred (Fig. 2). These areas may be preferred year-round habitat for these fish and further research, including monitoring during other times of the year, was recommended in order to further investigate this theory (Neufeld et al. 2010). Travel distances for juvenile and adult fish were not significantly different from each other and there were no significant travel-distance differences from the original point of tagging among fish tagged in the Pitt River and those tagged in the Fraser River (Neufeld et al. 2010).

Our project continued the 2009-10 study even further by continuing in the same manner throughout October and November 2011 as well as in January and February 2012.

2.0 Purpose and Objectives

This project has provided valuable scientific information regarding the overwintering habits and habitat preference in general, of white sturgeon in the Lower Fraser River watershed. By conducting this study we hope to identify and explain where these fish overwinter as well as their movements throughout this time period. This report is intended to add information to the existing bank of knowledge required to manage the Lower Fraser River white sturgeon population and enhance their survival and productivity. More specifically this report is written to better explain the movements of these fish throughout a sub-section of the Lower Fraser River watershed that is subject to intense human effects such as sport fishing, gravel extraction, bridge construction and pollution. By identifying key pre-winter and overwinter habitats and distribution tendencies and also key spawning and other seasonal habitats, we can better address specific conservation needs of these prehistoric creatures. Some geographic areas of interest have been established by the previous students study (Neufeld et al. 2010), and our project aimed to resurvey those areas and try to identify movements and distribution of the tagged sub-population over a given time period which may better explain movement patterns and distribution.

We hope to identify preferred habitats for given time periods and ascertain whether these fish show a tendency toward site fidelity, whether they be pre-winter or overwintering locations. We would also like to show if their movements are more nomadic and generalized or if preference is shown over an extended period of time for certain geographic locations.

3.0 Study Area

3.1 Site Description

3.2.1 Gravel Reach of the lower Fraser River

From Hope to the confluence of the Sumas River, the gravel reach’s substrate consists of gravel, cobble and to a lesser extent, sand (Ham, 2005). Erosion and deposition along islands, channel banks, and sediment accumulates to form bars and create a wandering river type (Ham, 2005). Although relatively unaltered compared to many other large rivers that flow through urbanized areas, riverine infrastructure such as dikes and bank protection structures have been installed in the gravel reach of the Fraser River over the last century narrowing the effective floodplain. In addition, channel dredging and removal of woody debris has been utilized to reduce flood probability, thus altering and ultimately destroying key habitats for these fish in all stages of their life cycles, whether it be spawning, rearing, or overwintering. This instream work alters the river’s natural floodplain in areas adjacent to local communities (Ham, 2005). This area has long been recognized as being highly productive spawning and rearing habitat for sturgeon and Pacific salmon including a myriad of habitats for some 30 different fish species (Rosenau & Angelo, 2007).

3.2.2 Sand Reach of the Lower Fraser and Pitt Rivers

Along the sand reach, from the confluence of the Sumas River at Mission to the Georgia Strait, sand and silt become the dominant benthic substrate material (Ham, 2005). Channel width and gradient determines the amount of entrapped sediment that settles within the reach (Ham, 2005).

The lower part of the sand reach is a heavily-used industrial area and commercial transportation route. The large amount of fine sediments that deposits in this reach causes navigational impediments and a portion of this material is dredged out for navigational purposes each year (Neufeld et al. 2010). Many side channels have also been isolated from river flows in this area due to extensive dyking.

The Lower Pitt River is a meandering sand-bottom river channel and connects the Lower Fraser River with Pitt Lake. Water levels can fluctuate 2 m in Pitt River within a tidal cycle and flows can reverse on the flood tide. The reversing Fraser River discharges in the Lower Pitt River has caused entrained sediments to be carried upstream on a flood flow and deposited at the southern end of Pitt Lake creating a large sandbar. Increasingly smaller sediments are deposited further and further upstream along the riverbed towards Pitt Lake. These deposits in the Lower Pitt River show a predominance of flood-oriented bed forms in the river channel and have resulted in a 12 km delta at the lower-draining end of Pitt Lake. The benthic stream-substrates present in the lower Pitt River are considered to be preferred eulachon (Thaleichthys pacificus) spawning habitat, which are an important source of food for sturgeon (Neufeld et. al, 2010).

The area surrounding the Lower Fraser River is the most densely populated part of the watershed. The lower Fraser River extends from Hope to the estuary at the mouth of the river, but the focus of our study is the stretch from the Port Mann Bridge at the downstream end and the confluence of the Sumas River at the upstream end. (Fig. 2). Historically, during the spring freshet, the Lower Fraser River inundated a considerable floodplain, spreading silt and sediments across the valley floor and rejuvenating the wetlands that supported abundant fish and wildlife. Today, much of the land in the Fraser Valley, including Maple Ridge, Pitt Meadows, Coquitlam, Richmond and Delta lies behind 600 km of dykes.

3.2.3 Project Study Areas

For the purposes of this study and following the previous years’ study design (Neufeld et. al 2010), we divided the Lower Fraser River into four separate study reaches, based on how much of the stream length could be surveyed in a day. They were as follows:

 Study Area 1- Port Mann Bridge upstream to Golden Ears Bridge including the Pitt River upstream to the Pitt River Bridge. (Fig. 3)

 Study Area 2- Pitt River Bridge upstream to Pitt Lake. (Fig. 4)

 Study Area 3- Golden Ears Bridge upstream to Mission Bridge. (Fig. 5)

 Study Area 4- Mission Bridge upstream to confluence of the Sumas River and the Fraser River. (Fig. 6)

Figure 3. Study Reach 1- Port Mann Bridge upstream to Golden Ears Bridge including the Lower Pitt River upstream to the Pitt River Bridge.

Figure 4. Study Reach 2- Encompasses a large portion of the Lower Pitt River starting at the Pitt River Bridge upstream to the outflow of Pitt Lake.

Figure 5. Study Reach 3- Golden Ears Bridge upstream to Mission Bridge including Derby Reach and Matsqui Channel.

Figure 6. Study Reach 4- Mission Bridge upstream to confluence of the Sumas River and the Fraser River.

4.0 Methods

For this study we tracked a previously sonic-tagged sub-population of Lower Fraser River white sturgeon (Robichaud 2010). We conducted mobile tracking of these fish throughout our study area on the Lower Pitt River and Lower Fraser River (Fig. 7).

Figure 7. Map showing the entire study area, with study reaches 1&4 shown in teal and study reaches 2&3 shown in pink.

As previously mentioned, there were four reaches within our study area. Monitoring was done one reach at a time, allocating one day for each study reach where possible within the study area and each reach was monitored at least twice throughout the time of the study. Our study took place from 25 October 2011 to 29 February 2012 and monitoring was done on a weekly basis where possible with some monitoring being performed on the weekend.

Using a VEMCO VR100 receiver and a VH110 directional hydrophone mounted on the Figure 8. 16' Hourston fiberglass boat used in the bow a 16’ Hourston fiberglass boat (Fig. 8), we study of white sturgeon on the Lower Fraser River traversed our study area monitoring potential tagged fish locations. Each reach was traversed from bank to bank at approximately a 45° angle in order to allow as much coverage of the study area by the hydrophone as possible.

Figure 9. This figure shows the approximate method of covering a given reach crossing from bank to bank at 45 degree angles at a slow speed to detect tags of tagged sturgeon.

Surveying from the boat was performed at a low speed and the hydrophone was submerged 60 cm under the water surface for optimal detection strength. The hydrophone received acoustic signals (pings) from the VEMCO V16 tags the sturgeon were implanted with. Each ping sent information to the receiver relaying tag numbers and the GPS location of the detection. This information was logged within the VR100 receiver including the individuals depth at detection. Depth was also confirmed with a Furuno LS-4100 echo sounder. Water temperature was taken within the reach on each study day with a mercury thermometer and manually recorded onto a data sheet. This was later confirmed with data from the Water Office of BC.

All logged data within the VR100 receiver were downloaded onto a personal computer using the most current software available from VEMCO. This was used to create maps through Google Earth and spreadsheets using Microsoft Excel 2010 and then further analyzed for results and conclusions.

5.0 Results 5.1 Overall Total Detections

Mobile tracking surveys for the 110 white sturgeon implanted with PIT tags by the FRSCS, were conducted on the Lower Fraser River from the Port Mann Bridge on the downstream end to the confluence of the Sumas Canal and the Fraser River at the upstream end, including The Lower Pitt River from its confluence with the Fraser River to its outlet from the lake proper.

Monitoring was performed from October 26th, 2011 to February 4th. 2012. Pre-winter surveys were performed 26-0ctober-2011, 02-November-2011, 09-November-2011, and 16-November- 2011. Over winter surveys were performed 18-January-2012, 25- January 2012, 28-January- 2012, 29-January-2012, 01-February-2012, and 04-February-2012. Throughout our study we had 40 total detections representing 19 individuals (Table. 1).

Table 1. Number of detections of white sturgeon by reach showing the total detections for the entire study area. Reach names were adopted from the previous study and relate to the closest city in relation to the stretch that was being surveyed except for the Pitt River, which is named for the river itself.

Survey Date Reach name/# Reach Description # of tags detected Pre-winter 26-Oct-11 Pitt River/2 Rkm P8 to Grant 6 (2 individuals) Narrows 02-Nov-11 Mission/4 Mission Bridge to 0 Dewdney Slough 09-Nov-11 Mission/4 Dewdney Slough to 0 Sumas Canal 16-Nov-11 Pitt River/2 Pitt River Bridge to 1 Rkm P8

Overwinter 18-Jan-12 Port Mann/1 Port Mann Bridge to 0 Golden Ears Bridge 25-Jan-12 Maple Ridge/3 Golden Ears Bridge to 5 (3 individuals) Crescent Island 28-Jan-12 Port Mann/1 Douglas Island and 2 Barnston Channel 29-Jan-12 Pitt River/2 Rkm P7-P16 23 (11 individuals) 01-Feb-12 Maple Ridge/3 Crescent Island to 4 (3 individuals) Mission Bridge 04-Feb-12 Mission/4 Mission Bridge to 0 Sumas Canal Total 40 (19 individuals)

The detections we recorded represents 16.4% of the original tagged sub-population of 110 fish. During our pre-winter surveys, from October 26th 2011 to November 16th 2011 we observed three separate individuals and detected two fish more than once on the same survey day. During our overwinter surveys, from January 25th 2012 to February 4th 2012, we observed 16 separate individuals and detected eight fish more than once on the same survey day. Of those 19 individuals, one (tag #23996), was not part of our tagged sub-population of 110 sturgeon. The origin of this tag is unknown.

Two of the 19 individuals detected were detected in both the pre-winter survey and the winter survey period. Our study identified 14 individuals that were originally tagged in the Pitt River, representing 77.8% of our total detections. The remaining 4 individuals or 22.2% were originally tagged in the Fraser.

Of the 18 individual detections that were identified, 12 individuals (67%) were observed to have a fork length (FL) >1 meter and the remaining 6 detected individuals (33%), had a FL < 1meter. Interestingly enough, 10 were new detections and 8 were previously detected in the past study. This represented 55.6% and 44.4 % respectively of the total detected individuals in the study. There appeared to be no significant difference in the size of the fish as it related to new detections, (capture) and previously detected in the 2010 study, (recapture) (Fig. 10).

Figure 10. Graph showing detections broken down by size class (< 1meter, > 1meter), and number of individuals detected, whether detected for the first time in the 2012 study, (capture) or previously detected in the 2010 study, (recapture).

The relative size distribution of our total detections throughout the study period was classed according to new detections and previous detections in order to show possible correlations with size and when each individual was detected (Fig. 11). There appeared to be a slightly greater range in size class with the previously detected individuals, but not significantly different enough to warrant further analysis.

Figure 11. Graph showing size range of individuals broken down by new detections, (2011-12) and previously detected , (2009-10).

During the period of our study, water temperature in the Lower Fraser River ranged from a high of 8.1°C in October 2011 to a low of 0.1°C in January 2012. Mean water temps during the fall survey period were ~5.2°C warmer than in the winter survey period. Flow rates from the Lower Fraser River, as measured at Hope for no tidal interference and as more of a true measure of actual flow (adapted from the Water Office of British Columbia) ranged from a high in October 2011 of 2189 m3/s to a low of 849 m3/s in January. The mean flow of the Lower Fraser River in 3 3 the fall study period was ~1750 m /s and in the winter study period it was ~1050 m /s.

5.2 Pre-winter and Overwinter Distribution and Movements of Sub-population of 110 tagged White Sturgeon in the Lower Fraser River, B.C.

Knowing seasonal distributions of white sturgeon in the Lower Fraser River is key to understanding the movements and habitat requirements of these fish. Thus to show differences, data have been categorized as pre-winter and overwinter data (Table 2&3).

Table 2. Pre-winter, (Oct 26th to Nov 16th 2011) detections of white sturgeon in the Lower Fraser River, BC. Repeat detections, (those fish detected in our study as well as the Neufeld study) are also shown as well as mean water temps for each survey day and an average for pre- winter and overwinter.

Reach # # of Detections Repeat Detections Water temp (C)

2 6 4 ~7.8

4 0 0 ~6.8

4 0 0 ~4.7

2 1 0 ~7.9

Total 7 4 ~6.8

Table 3. Overwinter, (Jan 18th to Feb 4th 2012) detections of white sturgeon in the Lower Fraser River, BC. Repeat detections, (those fish detected in our study as well as the Neufeld study) are also shown as well as mean water temps for each survey day and an average for pre-winter and overwinter.

Reach # # of Detections Repeat Detections Water temp (C)

1 2 0 ~0.9

2 22 12 ~1.4

3 9 1 ~1.4

4 0 0 ~0.9

Total 33 13 ~1.1

Minimum distance travelled was measured across both our study and the Neufeld study starting from the initial point of tagging, for fish that were detected in both studies. For fish that were newly detected then the minimum distance traveled was measured from the initial point of tagging only. When broken down by size class, juveniles being <1 meter fork length and adults being >1 meter fork length, the total distance travelled by the individuals detected was 118.4 km for the adults with an average of 16.9 km and the juveniles travelled a total of 86.1 km with an average of 7.8 km (Fig. 12&13) .

140

120

100

TOTAL DISTANCE TOTAL DISTANCE TRAVELLED (km) 0 <1 >1 SIZE OF STURGEON (m)

Figure 12. Graph showing total distance travelled by size class (<1 m, >1m).

0 AVERAGE AVERAGE DISTANCE TRAVELLED (km) <1 >1 SIZE OF STURGEON (m)

Figure 13. Graph showing average distance travelled by size class (<1 m,>1m).

We then looked at distance travelled by the 18 individuals detected over the entire time period from when they were originally tagged to when they were detected last regardless of size to gather a general trend in migration habits. Distances varied among the 18 individual detections from <1 km to ~37 km. We found seven individuals to have moved <1 km, representing 39% of our total detections. The other 11 individuals were observed to have travelled >5 km, representing 61% of our total detections (Fig. 14).

35 30 25 20 15 10

Distance (km) Travelled 5 0 0 50 100 150 200 Size of Sturgeon (cm)

Figure 14. Scatterplot showing individual detections by size and distance traveled with a general trend line inserted.

One of the original intents of this study and tagging program was to tag random individuals from both the Lower Fraser River as well as the Lower Pitt River. There was a need to identify differences and habits of fish caught from both systems and whether those habits or tendencies were significantly different or not. We made a comparison of original tagging locations, whether Fraser or Pitt River, and average distance travelled for both groups of fish that we detected in our study regardless of size (Fig. 14).

0 AVERAGE AVERAGE DISTANCE TRAVELLED (km) Pitt River Fraser River TAGGING LOCATION OF STURGEON

Figure 14. Graph showing average distance travelled for all sizes by original tagging location, Fraser or Pitt, (CI 9.7 and 6.1 respectively).

Of the sturgeon that we encountered, 10 of the 14 or 71.4% originally tagged in the Pitt remained in the Pitt with 4 individuals migrating out of the study area. Of the 4 that were originally tagged in the Fraser, 2 of the 4 or 50% remained in the Fraser and 2 individuals moved out of the study area. The whereabouts of these fish is unknown at this time.

A total of 92 individuals or 83.6% of the 110 originally tagged sub-population were not detected in the study area during our study period. The location of these undetected fish is not known at the present time.

6.0 Discussion The conservation concern for the future of white sturgeon in the Lower Fraser River has resulted in a need to both understand their movements and behaviors and as well, their habitat needs. The aim of this study was to survey a sub-population of white sturgeon caught and sonic-tagged in both the Lower Fraser and the Lower Pitt Rivers and determine their distribution, migration and possible areas of congregation in a predefined area from the Port Mann Bridge downstream to the confluence of the Fraser and the Sumas River.

6.1 Distribution of Detected Sturgeon Over the course of our study during both pre-winter and overwintering time periods we found the sturgeon we detected to be using somewhat homogenous areas of the river. They seemed to prefer main channels areas with slow moving water varying in depth from six to thirty meters. This seemed to be true for both the Fraser and the Pitt Rivers. Although we did not complete a full fall survey due to unforeseen circumstances, the area on the Lower Pitt River around rkm P11 (Ernie’s hole), was identified as an area that held fish in both the pre-winter and overwinter time periods. This is possibly significant in that this area was identified in the previous students study (Neufeld et. Al 2010). They found this area to be highly utilized both fall and winter as well. They found as did we, that the fish they detected were often originally tagged very close to their detection location. This return and usage of a given area by these fish could show site preference and fidelity to this location.

The fact that we had >50% new detections could suggest that new fish have either moved into the area recently where they had been elsewhere in the river before or were not found by the previous students work. Sampling effort and area coverage could be a possible explanation for this. Depending on the observer emphasis for a particular area, fish could possibly be overlooked.

Seasonal variations in abundance and distribution can most likely be attributed to survey limitations that saw us unable to complete a full pre-winter survey even though we did sample on 4 different days in October and November. Although another factor thought to possibly play a role in distribution is water temperature and food availability. Glova et al. (2008) similarly reported that when water temperatures dipped below 7ᵒ Celsius, sturgeon appeared largely sedentary. The report indicated that sturgeon were more likely to move more frequently as

temperatures climbed above the 7ᵒ Celsius mark. The hypothesis is that sturgeon decrease energy expenditure when food availability is low common in the winter months.

6.2 Habitat Utilization by Sturgeon Given the larger sample size of the previous students study in both the fall (pre-winter) and winter time periods, they were able to identify three possible areas of interest to sturgeon. These sites were; Douglas Island, Ernie’s hole, and possibly the confluence of the Stave and Fraser Rivers (Neufeld et al.2010).

Given the limitations of our study and our proportionally smaller sample size in both study periods, we were only able to identify Ernie’s hole as a specific area of distribution and congregation of these fish. Fish during our study were observed in this area consistently throughout our study period. This area is of interest because, as identified in the previous students study (Neufeld et al. 2010), they concluded that very little research had been done in the Lower Pitt River and specifically rkm P11 (Ernie’s hole).

During our study period, pre-winter and overwinter, we had no detections of fish in the upper portion of reach 03 and all of reach 04. The reasons for this remain unclear although these areas have been previously identified as possible sites of interest (Nelson et al.2008). One possibility may be that our tagged sub-population of sturgeon may have a preferred “home range” which lies outside of these areas.

7.0 Recommendations & Conclusions We would recommend a continuation of this BCIT and LGL partnership study program with the focus being on completing another full survey in both the fall and winter to identify information and data gaps of the current research. This would involve some expense however as the battery life expectancy of the implanted tags is approximately 4 years with 2012 marking the fourth year in which these tags have been in use. This could partially explain a lack in detections of the sub- population although it cannot be said for sure. Planning and organizing would have to be done to coordinate volunteer anglers and their boats to identify and tag another subpopulation of sturgeon in the both The Fraser and Lower Pitt River. We would suggest, as the previous students did that these questions be wholly or partially be addressed in subsequent studies:

 Would eliminating the upper most reach (reach 04), and adding a new reach from the Port Mann Bridge down to say the Alex Fraser Bridge identify any other individuals that our study did not?  Do sturgeon show habits and distribution that correlates with other possible happenings in the river, i.e. food availability?  Would adding night surveys to the study design help to identify specific movement patterns in either the pre-winter or overwinter time periods?  Do mature sturgeon show migration patterns that correlate to spawning events and distribution to known spawning areas, i.e. possibly Matsqui Channel?

Although we had original planned to get out and start our sampling in June of 2011, we were unable to due to unforeseen circumstances. Gathering data about these fish during other seasonal time periods, such as pre-fall, spring/freshet and summer, could be of great importance in understanding the movements and habits of these fish.

Identification of migration patterns and preferred seasonal habitats of Lower Fraser River white sturgeon populations is important for the conservation and protection of this endangered species. Areas where important feeding, staging, rearing and spawning habitat occur should be of focus and measures taken to secure these habitats for the future. Assessment of impacts to these critical sturgeon habitats prior to development, gravel extraction, dredging or riparian degradation are key for the future of this species.

References

Glova, G., Nelson, T., & Roberts, R. (2008-2009). An Interim Report on the Stewardship Approach toward the Development of a White Sturgeon Habitat Conservation and Protection Strategy in the Lower Fraser River. Richmond: Fraser River Sturgeon Conservation Society.

Ham, D. G. (2005). Morphodynamics and sediment transport in a wandering gravel-bed channel: Fraser River, British Columbia. Vancouver: The University of British Columbia.

Nelson, T. C., English, K. K., & Gazey, W. J. (2006). Status of White Sturgeon in the Lower Fraser River. Richmond: Fraser River Sturgeon Conservation Society.

Nelson, T. C., English, K. K., & Gazey, W. J. (2007). Status of White Sturgeon in the Lower Fraser River. Richmond: Fraser River Conservation Society.

Nelson, T. C., English, K. K., & Gazey, W. J. (2008). Status of White Sturgeon in the Lower Fraser River. Richmond: Fraser River Conservation Society.

Nelson, T. C., Gazey, W. J., English, K. K., & Rosenau, M. L. (1999-2004). Status of White Sturgeon in the Lower Fraser River. Vancouver: Fraser River Sturgeon Conservation Society.

Nelson, T. C., Robichaud, D., English, K. K., Mochizuki, T., Rosenau, M. L., Gazey, W. J., et al. (2010). Status of White Sturgeon in the Lower Fraser River. Vancouver: Fraser River Sturgeon Conservation Society.

Neufeld, P., Mothus, J., & Teubert, K. (2010). Distribution and Migration of Sonic-Tagged Sturgeon with Regards to Overwintering Habitat in the Lower Fraser River. Burnaby.

Rosenau, M. L., & Angelo, M. (2007). Saving the Heart of the Fraser. Vancouver: Pacific Fisheries Resource Conservation Council.

APPENDICES

APPENDIX A

White Sturgeon Monitoring Project Data Collection Form (2011-12)

Data Collection Date Sheet Number Area Monitored Observers Water Flow Tag Depth Temp. Rate Time Time Fish Number number (m) (Celsius) (cm/s) Start End Comments

Appendix B Tagging Locations, Tag I.D. Numbers, Tag Date, Fork Length and Girth measurements of Sub- population of White Sturgeon. (Neufeld et. Al 2010) Yellow- New Detection Green-Repeat Tag Fork Length Girth Sturgeon # Tagging Location I.D. # Tagging Date (cm) (cm) between rkm 39 & Port Mann 1 Bridge 23669 23-Aug-08 85 31 between rkm 39 & Port Mann 2 Bridge 23670 23-Aug-08 107 38.5 between rkm 39 & Port Mann 3 Bridge 23671 30-Aug-08 71.5 26.5 between rkm 39 & Port Mann 4 Bridge 23672 30-Aug-08 172 67.5 between rkm 39 & Port Mann 5 Bridge 23673 30-Aug-08 62 23 between rkm 39 & Port Mann 6 Bridge 23674 30-Aug-08 90 32.5 between rkm 39 & Port Mann 7 Bridge 23675 30-Aug-08 70 25.5 between rkm 39 & Port Mann 8 Bridge 23676 30-Aug-08 105 43.5 between rkm 39 & Port Mann 9 Bridge 23677 31-Aug-08 152 57 between rkm 39 & Port Mann 10 Bridge 23678 31-Aug-08 88.5 33 between rkm 39 & Port Mann 11 Bridge 23679 31-Aug-08 105.5 39.5 between rkm 39 & Port Mann 12 Bridge 23681 31-Aug-08 97 38.5 between rkm 39 & Port Mann 13 Bridge 23685 31-Aug-08 150 60 between rkm 39 & Port Mann 14 Bridge 23687 31-Aug-08 80 28 between rkm 39 & Port Mann 15 Bridge 23683 31-Aug-08 144 56 between rkm 39 & Port Mann 16 Bridge 23684 31-Aug-08 93 35 between rkm 39 & Port Mann 17 Bridge 23680 31-Aug-08 133.5 54 between rkm 39 & Port Mann 18 Bridge 23682 31-Aug-08 115 43.5

Tag Fork Length Girth Sturgeon # Tagging Location I.D. # Tagging Date (cm) (cm) between rkm 39 & Port Mann 19 Bridge 23686 31-Aug-08 146 58 between rkm 39 & Port Mann 20 Bridge 23688 31-Aug-08 92 32.5 between rkm 39 & Port Mann 21 Bridge 23689 31-Aug-08 107.5 43 between rkm 39 & Port Mann 22 Bridge 23690 31-Aug-08 99.5 43 between rkm 39 & Port Mann 23 Bridge 23691 31-Aug-08 112 40 between rkm 39 & Port Mann 24 Bridge 23692 31-Aug-08 118.5 48 between rkm 39 & Port Mann 25 Bridge 23693 31-Aug-08 117 44.5 between rkm 39 & Port Mann 26 Bridge 23694 31-Aug-08 140 52 between rkm 39 & Port Mann 27 Bridge 23695 31-Aug-08 117.5 46 between rkm 39 & Port Mann 28 Bridge 23697 30-Aug-08 99 37 between rkm 39 & Port Mann 29 Bridge 23698 30-Aug-08 96 36 between rkm 39 & Port Mann 30 Bridge 23700 30-Aug-08 74 26.5 between rkm 39 & Port Mann 31 Bridge 23702 31-Aug-08 99.5 38.5 between rkm 39 & Port Mann 32 Bridge 23703 31-Aug-08 131 50.5 33 just below rkm 55 23696 31-Aug-08 103 40 34 just below rkm 55 23701 10-Jun-08 184.5 86 35 just below rkm 55 23704 10-Jun-08 116.5 47 36 just below rkm 55 23707 10-Jun-08 171 69 37 just below rkm 55 23708 10-Jun-08 129 48 38 just below rkm 55 23709 10-Jun-08 155.5 61 39 just below rkm 55 23710 10-Jun-08 131 52 40 just below rkm 55 23711 10-Jun-08 142 52.5 41 just below rkm 55 23712 10-Jun-08 186.5 77.5 42 just below rkm 55 23713 10-Jun-08 114 43 43 just below rkm 55 23714 10-Jun-08 203 81 44 just below rkm 55 23715 10-Jun-08 101 36 45 just below rkm 55 23716 10-Jun-08 124 51 46 just below rkm 55 23718 10-Jun-08 108 40 47 just below rkm 55 23717 10-Jun-08 131 50.5

Tag Fork Length Girth Sturgeon # Tagging Location I.D. # Tagging Date (cm) (cm) 48 just below rkm 55 23719 10-Jun-08 166 66.5 49 just below rkm 55 23720 10-Jun-08 108 40 50 just below rkm 55 23721 10-Jun-08 101.5 38 52 just below rkm 55 23724 10-Jun-08 82 30 53 just below rkm 55 23723 10-Jun-08 149.5 59 54 just below rkm 55 23725 10-Jun-08 130.5 45 55 just below rkm 55 23727 10-Jun-08 132.5 51 56 just below rkm 55 23729 10-Jun-08 130.5 52.5 51 just below rkm 55 23722 10-Jun-08 163 57.5 57 just below rkm 55 23730 10-Jun-08 182 64 58 just below rkm 55 23699 10-Jul-08 109.5 45 59 just below rkm 55 23705 10-Jul-08 100.5 37 60 just below rkm 55 23706 10-Jul-08 96 37 61 just below rkm 55 23726 10-Jul-08 93.5 37 62 just below rkm 55 23728 10-Jul-08 108 40 63 just below rkm 55 23731 10-Jul-08 71 29 64 just below rkm 55 23732 10-Jul-08 144 53 65 just below rkm 55 23733 10-Jul-08 79 29.5 66 just below rkm 55 23734 10-Jul-08 153 63 67 just below rkm 55 23735 10-Jul-08 132 50 68 just below rkm 55 23736 6-Jan-09 101 38 69 just below rkm 55 23737 6-Jan-09 139 56 70 just below rkm 55 23738 6-Jan-09 130 48 71 just below rkm 55 23739 6-Jan-09 111.5 44 72 just below rkm 55 23740 6-Jan-09 87 31 73 just below rkm 55 23741 6-Jan-09 79.5 30 74 just below rkm 55 23742 6-Jan-09 120 44 75 just below rkm 55 23743 6-Jan-09 106 45 between rkm 39 & Port Mann 76 Bridge 23744 6-Jan-09 151.5 59 between rkm 39 & Port Mann 77 Bridge 23745 6-Jan-09 67.5 25 between rkm 39 & Port Mann 78 Bridge 23746 6-Jan-09 74.5 28.5 between rkm 39 & Port Mann 79 Bridge 23747 6-Jan-09 92.5 34.5 80 just below rkm 55 23748 6-Feb-09 108 39 81 just below rkm 55 23749 6-Feb-09 167 62.5 82 just below rkm 55 23750 6-Feb-09 90.5 35 83 just below rkm 55 23751 6-Feb-09 141.5 53.5

Tag Fork Length Girth Sturgeon # Tagging Location I.D. # Tagging Date (cm) (cm) 84 just below rkm 55 23752 6-Feb-09 69 29.5 85 just below rkm 55 23753 6-Feb-09 177.5 71.5 86 just below rkm 55 23754 6-Feb-09 166 60 87 just below rkm 55 23755 6-Feb-09 98 39 between rkm 39 & Port Mann 88 Bridge 23756 6-Feb-09 88.5 30 between rkm 39 & Port Mann 89 Bridge 23757 6-Feb-09 100.5 39 between rkm 39 & Port Mann 90 Bridge 23758 6-Feb-09 78 29.5 between rkm 39 & Port Mann 91 Bridge 23759 6-Feb-09 139 53 between rkm 39 & Port Mann 92 Bridge 23760 6-Feb-09 78.5 30 between rkm 39 & Port Mann 93 Bridge 23761 6-Feb-09 133.5 48 between rkm 39 & Port Mann 94 Bridge 23762 6-Feb-09 81 32.5 between rkm 39 & Port Mann 95 Bridge 23763 6-Feb-09 64 25.5 between rkm 39 & Port Mann 96 Bridge 23764 6-Feb-09 138.5 57.5 97 just below rkm 55 23765 6-Mar-09 101.5 38 98 just below rkm 55 23766 6-Mar-09 93 34 99 just below rkm 55 23767 6-Mar-09 100 40 100 just below rkm 55 23768 6-Mar-09 94.5 34 101 just below rkm 55 26533 6-Mar-09 62 26 102 just below rkm 55 26534 6-Mar-09 131.5 54 103 just below rkm 55 26535 6-Mar-09 71 27 between rkm 39 & Port Mann 104 Bridge 26536 6-Mar-09 117.5 42.5 between rkm 39 & Port Mann 105 Bridge 26537 6-Mar-09 85 31.5 between rkm 39 & Port Mann 106 Bridge 26538 6-Mar-09 96 36.5 between rkm 39 & Port Mann 107 Bridge 26539 6-Mar-09 141 53 between rkm 39 & Port Mann 108 Bridge 26540 6-Mar-09 101.5 35.5 between rkm 39 & Port Mann 109 Bridge 26541 6-Mar-09 105 41 between rkm 39 & Port Mann 110 Bridge 26542 6-Mar-09 91 36.5

APPENDIX C

Data Collection Sheets Oct 2011-Feb 2012

APPENDIX D

Maps of tagged sturgeon detections from October 26, 2011 through to February 02, 2012. Numbers beside detections coincide with actual fish numbers that were assigned to the population when initially tagged. Appendix B can be used to correlate fish numbers with size, weight, date tagged and tagging location.

APPENDIX E

Graphs showing flow rate and temperatures of the Lower Fraser River at Hope B.C. These figures correspond to each study day from October 26, 2011 through to February 04, 2012. As well, a graph showing flow rate and temperature of the Lower Fraser River at Hope for the period between October 2011 and February 2012. Graphs were adapted from the Water Office of B.C.

APPENDIX F Movements of individual sturgeon that were detected during survey days, dates on detection locations are the dates that the sturgeon was detected during our study. To match numbers on detection locations with acoustic tags applied to each fish, as well as the size, date and location when it was tagged use Appendix B.