British Columbia Rockfish Abundance Survey 2017

Transcription

1 British Columbia Rockfish Abundance Survey 2017 Laura Borden and Jeff Marliave Vancouver Aquarium February

2 A Brief History of Rockfish in British Columbia Rockfish experienced severe depletion in coastal waters through the early 1990s when a historic low was reached. Black and Bocaccio Rockfish were extirpated in Howe Sound in the 1960s through the use of downrigger weights on salmon flashers (pers. comm. Jeff Marliave), and reef by reef serial depletion of occurred during the 1980s. It was in 1986 that the first licenses were issued for the live-market fisheries (Yamanaka and Logan 2010). Prior to 1986 there were no restrictions or management actions in place to protect populations of in British Columbia. With the advent of fishing licenses, landings quadrupled between 1986 and 1990 (Yamanaka and Logan 2010). It wasn t until 1996 that total allowable catches (TACs) were defined at the species level for ; previous TACs were based on groups of, such as the red which were a collection of five different species targeted for harvest, or other (Yamanaka and Lacko 2001). Due to the unique life span of each species of ranging from a couple of decades to over 110 years grouping of species together can easily lead to decline in the longest lived species, as was the case with the red Yelloweye during the 1980s (Yamanaka and Lacko 2001). Through extensive consultation with scientists and the public, a conservation strategy was put forward in 2002 that would see the establishment of refuges (Yamanaka and Logan 2010). In 2007 Fisheries and Oceans Canada finalized 164 Rockfish Conservation Areas (RCAs) ranging from Haida Gwaii to the southern Strait of Georgia. These 164 RCAs represent 20% of habitat along the BC coast. In addition to RCA closures, all hookand-line fishing for groundfish (lingcod and ) in area 28 and area 29 was banned in summer of Between 2009 and 2011 Haggarty et al looked at the effectiveness of these RCAs and showed that habitat relief and depth influenced density but designation as an RCA did not. It is believed that recreational fishing compliance within the designated conservation areas is an issue limiting the effectiveness of RCAs (Haggarty et al. 2013). However, it is important to consider the life span of some species of Yelloweye have been aged to over 100 years old meaning detectable recovery would not necessarily be expected on the order of a few years or even a decade. Rockfish can be found at scuba depths year-round; however, recent studies by The Coastal Ocean Research Institute s Howe Sound Research Program have found that some hide during the winter, making them more difficult to see. This behavior can be observed from as early as October to the end of May, where live deep within multi-layered rock piles. Over the peak winter hiding period (December to March), divers have observed an average of 18 for a population known to be home to over 250 individuals. As a result, dives conducted during this time may yield lower than expected counts, thus it is suggested that participants of the Rockfish Abundance Survey primarily conduct their surveys during good visibility periods between August and October. Dives logged during the annual Rockfish Abundance Survey are performed by divers from the community as well as aquarium staff. Divers are enlisted through a variety of sources including dive organizations, stores, charters, magazines, and personal contacts. Aquarium staff survey 2

3 efforts are generally limited to Howe Sound. Peter Meiras, owner and operator of Rendezvous Dive Adventures on the west coast of Vancouver Island has generously contributed educational videos for this survey. His video on species identification can be found on the survey website. Biology of Rockfish There are 37 species of along the BC coast, five of which are considered inshore and are primarily found in rocky reef habitats. Each species can be distinguished based on a variety of characteristics including colour/colour pattern, shape and size, and sometimes depth (Love et al. 2002). Rockfish Conservation Areas, defined in 2007 by DFO, are intended to protect the five inshore species: Yelloweye, Quillback, Copper, China and Tiger Rockfish. Quillback Rockfish are listed as threatened by COSEWIC, while Yelloweye Rockfish are listed as special concern. Rockfish are typically long-lived species, some with more than a century lifespan, and as such take longer to mature and reproduce. They mate in the fall and give Adult Tiger Rockfish. Photo by Charlie Gibbs birth to free-swimming larvae that eventually settle on rocky reefs. Inshore do not typically stray far from their home (Hannah and Rankin 2011), making them an easy target in sport fisheries and highly susceptible to overfishing. Mature, large female give birth to larger babies with the greatest chance of survival (Berkley et al. 2004). As a result, overfishing of large can have a severe impact on the success of the next generation. Rockfish are also uniquely impacted by catch-and-release practices; during rapid ascent to the surface, their gas-filled swim bladder quickly expands, greatly reducing their likelihood of survival after such barotrauma (Rummer and Bennett 2005). Survey Instructions This year marked the 13 th annual Rockfish Abundance Survey (RAS) conducted by the Coastal Ocean Research Institute, an Ocean Wise initiative. The survey was initiated in 2005 prior to the 2007 introduction of 164 Rockfish Conservation Areas (RCAs) in British Columbia. The survey enlists the help of divers from the community to census populations both inside and outside conservation areas in order to examine the effectiveness of RCAs in protecting inshore as well as track the recovery of from the historic low 3

4 reached in the 1990s. The Rockfish Abundance Survey occurs over a three month period (August-October) to account for hiding, and to avoid low visibility during springtime blooms. During hiding, can be hard to see as they hide deep within rock piles in winter months, making it difficult to get an accurate estimate of abundance. The purpose of this survey is to estimate abundance using a count per unit effort measure in a given area by having divers count the number of, noting the species and size (age, adult vs. juvenile vs. young of the year), during the dive. Bottom time, average depth and maximum depth are also recorded. With this information, the abundance of in the given area is calculated using a count per unit effort index (CPUE) which is the number of counted per hour diving. This index can provide an estimate of the relative abundance of populations, and show how populations are changing over time (Haggarty and King 2006). Alternatively, divers can take videos of their dive and use that footage to count and identify the after the dive. An instruction booklet outlining all the pertinent information for divers can be found on the Vancouver Aquarium s survey website: Sample dive slate: Date 09/06/16 09/07/16 General Location Howe Sound Howe Sound Specific Location Porteau Cove Whytecliff Park Bottom Time (min) Max Depth (ft) Average Depth (ft) # of adult Copper Rockfish Adult Copper Rockfish CPUE 6067/32 = / =26 calculated by the Aquarium after data collation (60min x # fish/#minutes = # fish per h) All data are sent to the Aquarium or entered online through the survey website. Once the data are sorted the index of abundance, a Count Per Unit Effort (CPUE), is calculated. The CPUE is the number of of an individual species and age sighted per hour. It is calculated by multiplying the number of by 60, divided by the bottom time. Results and Discussion The 13 th annual Rockfish Abundance Survey was conducted between August and October Participants from around British Columbia and Ocean Wise staff undertook 148 dives totaling over 122 hours underwater. This year s survey covered the largest geographic area, ranging from the Central Coast to Victoria to the San Juan Islands and all across the Strait of Georgia (table 2). In all, there were fourteen species or identified from newly settled young of year copper, schools of one-year-old Yellowtail Rockfish and decades old Yelloweye Rockfish. 4

5 Northern British Columbia.Alaska Outer Coast Washington Strait of Georgia West Coast Vancouver Island Rockfish Abundance (Count 60min -1 ) Map 1. Zoogeographic regions of British Columbia south coast and Washington, as described by Marliave et al Rockfish abundance varied by zoogeographic region (map 1) with the greatest abundance in Northern British Columbia/Alaska (figure 1; 19 surveys). This is the first year data for the Rockfish Abundance Survey has been submitted for this region, however data are limited to the central coast area and does not include the north coast or Haida Gwaii. Surveys in San Juan Islands, a part of the outer coast Washington region, were also a first in The average number of seen on a dive in this zoogeographic region was 400 (six surveys); this CPUE is greater than for both the Strait of Georgia (94 surveys) and West Coast of Vancouver Island (29 surveys) Zoogeographic Region Figure 1. Total abundance (count per unit effort 60min) in 2017 based on zoogeographic regions. Results compiled from 148 scuba dive surveys. Refer to Map 1 for zoogeographic regions. 5

6 Map 2. Geographic area breakdown for British Columbia south coast and Washington. 6

7 Barkley Sound Central Coast Howe Sound Northern Gulf Islands Parksville Saanich Inlet San Juan Islands Southern Gulf Islands Strait of Juan de Fuca Victoria Rockfish Abundance (count 60min-1) Variability in abundance is also evident on a smaller geographic scale (map 2; figure 2, 3). With the exception of the Southern Gulf Islands, all areas had a total abundance of at least 100 per 60min survey effort in Three of the four areas with the highest abundance of were in outer coast regions (often termed outside waters); the fourth area with a noticeably greater abundance of was Howe Sound. This was the only area in the Strait of Georgia with an average abundance of over 300, a significant jump over previous abundance counts for Howe Sound (figure 4). Only Howe Sound, Barkley Sound and Victoria have seen a significant rise in abundance in the past two years. The primary driver of this rise was the booming year class of yellowtail from Young-of-year Yellowtails were seen in outside waters in 2016 and then in some inside water areas Howe Sound in particular in 2017 as one year olds. Schools of over 1000 one-yearold yellowtail were observed throughout Howe Sound this year. All other species of remained in similar abundance to previous years. It appears neither Saanich Inlet or the Southern Gulf Islands experienced the same increase in Yellowtail, instead seeing a consistent abundance of over the past five year (figure 4). Indian Arm (not surveyed in 2017) has consistently had a lower abundance of than all other areas Figure 2.Total abundance (count per unit effort 60min) for each area in Results compiled from 148 scuba dive surveys. Refer to Map 2 for areas. Another important change in Howe Sound in 2017 was the sighting of one-year-old Black Howe Sound. Though their presence did not change the overall abundance of the species, they indicate a successful year class of Black, something not seen by divers since This is also a noteworthy observation since Black were one of two species extirpated in 1960s; Black were subsequently reintroduced in the early 2000s at Point Atkinson. 7

8 Rockfish Abundance (Count 60min -1 ) Barkley Sound Central Coast Howe Sound Northern Gulf Islands Parksville Saanich Inlet San Juan Islands Southern Gulf Islands Strait of Juan de Fuca Victoria Rockfish Abundance (count 60min -1 ) Figure 3. Rockfish abundance broken down by age category. Blue = young of year, red = juvenile and green = adult. Results compiled from 148 scuba dive surveys. Refer to Map 2 for areas Figure 4. Abundance of (count per 60min survey effort) for each Geographic Area: blue = Barkley Sound, green= Indian Arm, red = Howe Sound, purple = Parksville, Turquoise = Saanich Inlet, orange = Southern Gulf Islands and light blue = Victoria. 8

9 Table 1. Summary of species distributions by area. Agamemnon Barkley Sound Baynes Sound Burrard Inlet Campbell River Central Coast Haida Gwaii Howe Sound Jervis Kyuquot/Brooks NEVI NWVI NGI Nanaimo copper quillback brown China yellowtail boulders, shallow boulders, all depths boulders, shallow territorial, solitary, crevices black deacon bocaccio silvergray widow Puget Sound canary vermilion crevices loose aggregations loose aggregations tiger yelloweye territorial, solitary, crevices juveniles more common, all depths redstripe greenstriped deeper deeper 9

10 Nootka Parksville Puget Sound Saanich SE Mainland San Juans Sechelt SoG outside HS inside SGI SoG SGI Sunshine N Sunshine S Strait of Juan de Fuca Ucluelet/Tofino copper quillback brown boulders, shallow boulders, all depths boulders, shallow China territorial, solitary, crevices yellowtail black deacon bocaccio silvergray widow Puget Sound crevices canary loose aggregations vermilion tiger yelloweye redstripe loose aggregations territorial, solitary, crevices juveniles more common, all depths deeper greenstriped deeper always seen (100%) often seen (66-99%) sometimes seen (33-66%) rarely seen (1-33%) trace (1%) no data 10

11 Rockfish Abundance (Count 60min-1) Selected Sites Rockfish tend to have a small home range (Hannah and Rankin 2011), and as such we have looked at the smallest geographic scale to identify site-by-site changes in abundance. We selected five sites that have been the most consistently surveyed over the past ten years to see how abundance has changed since 2007 (figure 5). Two sites within the Strait of Georgia, Whytecliff Park and Maple Bay, have not seen any significant change in overall abundance since 2007 and 2010, respectively. Madrona Point in Parksville, surveyed since 2009, has seen an average of nearly 300 per 60min survey effort over the past four years, compared to low abundance records from single surveys conducted in 2009 and Ogden Point, Victoria and Renate Reef, Barkley Sound saw a jump in overall abundance in 2016, the same year as the large young-of-year Yellowtail boom. It is only through repeated, year-over-year surveys at the same sites that we can effectively track the health of individual populations and map out where events, such as a Yellowtail boom, occur. This information can also be informative when evaluating the effectiveness of protected areas such as RCAs or MPAs Figure 5. Rockfish abundance, a count per 60min survey effort, at selected sites in Howe Sound (Whytecliff dark blue), Southern Gulf Islands (Maple Bay purple), Parksville (Madrona Point light blue), Victoria (Ogden Point green) and Barkley Sound (Renate Reef red) since Threats The main threat to populations along the BC coast is as bycatch, particularly in the Strait of Georgia where stocks have been greatly reduced. A recent study (Haggarty et al. 2016) examining the effectiveness of Rockfish Conservation Areas (RCAs) showed that there is an issue with lack of compliance with fishing regulations in these areas. The authors suggest that lack of compliance is related to a lack of knowledge on the part of the fishermen. By 11

12 including the boundaries of RCAs on digital GPS charts, it could make it easier for a fisherman to see when they are within an RCA, hopefully improving compliance. As a long-lived species, recovery of populations is expected to be a long term process but protected areas that allow for populations to stabilize and have multiple successful year classes will lead to healthier populations of in BC. Solutions Provided that the aim of RCAs was to rebuild depleted stocks that can then replenish neighbouring, unprotected areas, the first solution to fishing pressure on should be to increase compliance by making resources visually available in GPS systems on board of fishing vessels (Haggarty et al. 2016). An increase in resources for enforcement of existing regulations would also likely contribute to a reduction in fishing pressure. How can you help? The Rockfish Abundance Survey is a citizen science driven project that heavily relies on the public s contributions to survey efforts. Over the past five years, citizen scientists have contributed over 50% of survey reports. By participating in this survey, divers can aid in our effort to track the long term trends in abundance in BC. Not a diver? You can still contribute to conservation by following local fishing regulations and reporting any violations to the Department of Fisheries and Oceans (DFO). The Rockfish Abundance Survey (RAS) is not the only fish census conducted by Ocean Wise. During a five-week period centering on late February, Ocean Wise researchers census spawning Lingcod populations along the BC coast. The Lingcod Egg Mass Survey (LEMS) was launched in 1994 by the Marine Life Sanctuaries Society (MLSS) and since 1996 the Vancouver Aquarium has promoted and collated the data for the survey ( These two annual surveys provide our team with the ability to inform government decision-making on which areas afford the best protection for inshore and Lingcod populations. (See next page for summary chart of abundance by geographic area) 12

13 Table 2. Summary of counts, by area, including the seven most commonly seen, total abundance, number of survey submissions and total underwater survey time. Area # of Dives Total time (min) Total Rockfish CPUE Copper CPUE Quillback CPUE Puget Sound CPUE Tiger CPUE Yellowtail CPUE Black CPUE Brown CPUE Grand Total Howe Sound Northern Gulf Islands Parksville Saanich Inlet Southern Gulf Islands Victoria Barkley Sound Strait of Juan de Fuca San Juan Islands Central Coast This includes all stages of (YOY, juvenile and adult), representing the total number of a diver encountered per 60min of diving. 13

14 References Haggarty, D. R. and J. R. King CPUE as an index of relative abundance for nearshore reef fishes. Fisheries Research, 81: Haggarty. D. R., J. B. Shurin and K. L. Yamanaka Assessing population recovery inside British Columbia s Rockfish Conservation Areas with a remotely operated vehicle. Fisheries Research, 183: Haggarty, D. R., S. D. J. Martell, and J. B. Shurin Lack of recreational fishing compliance may compromise effectiveness of Rockfish Conservation Areas in British Columbia. Canadian Journal of Fisheries Aquatic Science, 73: Hannah, R. W. and P. S. Rankin Site fidelity and movement of eight species of pacific at a high-relief rocky reef on the Oregon coast. American Fisheries Society, 31: Love, M. S., M. Yoklavich, and L. Thorsteinson The es of the northeast Pacific. University of California Press, Berkeley. Marliave, J. B., C. J. Gibbs, D. M. Gibbs, A. O. Lamb and S. F. J. Young Biodiversity stability of shallow marine benthos in Strait of Georgia, British Columbia, Canada through climate regimes, overfishing and ocean acidification, pp In: Biodiversity loss in a change planet, Oscar Grillo and Gianfranco Venora (Eds.), ISBN: Rummer, J. L. and W. A. Bennett Physiological effects of swim bladder overexpansion and catastrophic decompression on red snapper. Transactions of the American Fisheries Society, 134: Yamanaka, K. L. and G. Logan Developing British Columbia's Inshore Rockfish Conservation Strategy, Marine and Coastal Fisheries, 2:1, Yamanaka, K. L., and L. C. Lacko Inshore (Sebastes ruberrimus, S. maliger, S. caurinus, S. melanops, S. nigrocinctus and S. nebulosus) stock assessment for the West Coast of Canada and recommendations for management. Canadian Science Advisory. Secretariat Research Document 2001/