Many Canadian Coho Management Units (MUs) have been “data limited” since the reduction in assessment priority for coho which started about the same time as the Southern Coho Plan was finalized in 2002. The implementation plan for the 2020 Pacific Salmon Treaty (PST) brings an opportunity to improve coho assessment and management. The PST Chapter 5 Southern Coho management framework is based on assessment of Canadian and US management units into one of 3 status zones (Low, Moderate, and Abundant), which have commensurate total exploitation rate (ER) caps and sharing of this ER between the US and Canada. This proposed approach could address the current inability to assess status in several Canadian MUs.
Tools such as DNA can accurately identify wild coho to the Conservation Unit (CU), MU, or even river of origin and can accurately identify hatchery of origin through a combination of parental based tagging (PBT) and regular genetic stock identification (GSI) (see Beacham et al. 2019). We propose that these assessment tools can be the basis for estimating wild coho escapement.
The proposed approach uses September fishery information, combined with representative DNA information from the fishery and escapement results from key hatchery indicators, to form the basis for estimating aggregate escapement of wild coho, especially in the GST management unit, but also Lower Fraser, Southwest Vancouver Island (SWVI), and other stock aggregates. The objective is to track catch of wild coho catch and escapement by management unit. These tools will also be used to estimate exploitation rate.
We propose a workshop to review the current approaches to assessing and modelling salmon survival across freshwater/coastal and marine life history stages and to recommend options that will inform the host of management tools/processes that require consideration of the full life history. We will bring together experts possessing experience with these techniques to share their knowledge in a structured manner. Case studies drawn from Pacific Salmon Treaty stocks that have requisite information will be developed that can be used to test the modelling approach. A Workshop Technical Planning Team will be convened from North Pacific Anadromous Fish Commission -International Year of the Salmon partner government agencies, NGO’s and academia to ensure relevance of the work to management and to assist in identifying a complete complement of experts. Experts will include representatives from Pacific Salmon Commission Secretariat staff and Technical Committees (Chinook, Coho, Chum and Sockeye). We will support travel for experts from Asia, Canada, Europe and the U.S. to attend. It will be essential for us to incorporate approaches to understanding freshwater and marine ecosystem status with Indigenous Peoples. Additionally, we will assess the potential for the development of new and emerging technologies and citizen science to augment this work.
Presently, only two index streams are surveyed for chinook salmon in Area 27 on Northern Vancouver Island. Both streams have been influenced by present or past hatchery operations and escapement estimates reflect marine mortality rates, as well as hatchery production rates. East Creek is a moderately sized system flows just north of Brooks Peninsula, and has only recently become accessible by logging road. Historical surveys associated with expanding hatchery production in the period 1960-1980 revealed a natural chinook population in East Creek but there has been no history of hatchery augmentation.
Establishing an index snorkel survey in East Creek would provide an opportunity to examine population abundance trends in a system unaffected by hatchery production. We propose to establish an index snorkel survey in East Creek, and to determine possible hatchery stray contributions through a complete sampling program including DNA, scales and otoliths on adult chinook post-spawn mortalities.
Due to the complicated life history of Pacific salmon, which environmental factor (s) has major influences on their growth and productivity remains unknown, particularly accounting for their entire life history. Most previous studies focus on the short time period when they first enter the ocean. We will fill the gap by investigating salmon growth in all their marine years. We plan to use Chum salmon in southern British Columbia as an example to address this question because Chum salmon migrate to the ocean right after hatching, providing the great candidate to compare marine growth in the multiple years and seasons.
We propose to process the historic scales, measuring the seasonal (summer and winter separately) growth and identifying stocks, to reconstruct stock-specific long-term time series of growth rates of Chum salmon in multiple ocean years. Fish scales provide a record of individual growth during their entire life history and have long been used to study age structure and growth. The scales of Chum salmon have been consistently collected with fish length measured during a test fishery in Johnstone Strait since 1980. In recent years, along with the scales, tissues for genetic stock identification have been collected and processed on a fairly consistent basis from that test fishery. The number of stock-specific adult returns (2008-2019) can be estimated using the Chum Genetic and Environmental Management Model (ChumGEM) based on recent catch, escapement, and the genetic data.
By linking growth rates of Chum salmon stocks with density dependence and ocean conditions (1980-2019), this project will attempt to define which environmental factor(s) would be the best indicator of returns for each stock; by linking growth rates of Chum salmon stocks with the stock-specific adult returns, this project will determine which season and year of growth rate would be the best indicator of adult returns for each stock.
We propose to conduct salmon counting surveys on four streams in the traditional area of Snaw-Naw-As (Nanoose) First Nation, including Nanoose Creek (Area 17-20), Knarston Creek (Area 17-19), Bloods Creek (Area 17-18), and Craig Creek (Area 14-1), to estimate escapement of Coho and Chum salmon returning in 2019. Final escapement estimates will be generated through the use of two methods: (1) AUC variation modelling to calculate confidence bounded estimates of escapement modelled for observer efficiency and streamresidence time, and (2) an expanded peak count method.
A minimum of 16 ground surveys are proposed and been budgeted to conduct escapement counts in the four streams during peak Coho and Chum salmon migration with a minimum of four trips planned to each system. These four streams have not been assessed for 14 years. The project budget also includes analyses and reporting of survey and habitat data (including mapping support) as well as appropriate survey gear for crew. Herein we propose to conduct multiple surveys in several local creeks in DFO Statistical Areas 14 and 17 to generate an AUC escapement estimate for Coho salmon in the 2019 return year. If funded, this would be the first time these streams have been assessed since early 2000’s.
Producing more hatchery Chinook salmon juveniles has recently been proposed in Washington State with hopes of enhanced ecosystem and fisheries benefits. However, it has recently been shown that even the vast North Pacific Ocean cannot support an infinite number of salmon (Ruggerone and Irvine 2018), and it appears that mortality of salmon in the Salish Sea can also be density dependent (Ruggerone and Goetz 2004). Density-dependent effects between pink salmon in particular (the most numerous species, but also chum salmon) and Chinook salmon have been documented by an increasing number of studies (e.g., Ruggerone and Nielsen 2004; Ruggerone et al. 2003), suggesting that salmon compete for food in the ocean, which can lead to reduced growth, delayed age at maturation, and lower survival rates (Ruggerone and Irvine 2018). Preliminary analyses of the relationships between Chinook salmon hatchery production and numbers surviving to adulthood suggest reduced Chinook survival in years when large numbers of juvenile pink salmon also out-migrate. In some regions, this density-dependent mortality may be so strong that large increases in hatchery releases may limit the number of returning adults.
We propose to evaluate the following questions: what Chinook salmon juvenile release abundance values are associated with greatest marine survival rates? How do survival rates vary with different numbers of juvenile pink salmon out-migrating in the Salish Sea? How do these relationships differ among Chinook salmon stocks from various regions of the Salish Sea?
S19-SP33 Optimization of hatchery Chinook releases in the Salish Sea through ecosystem-based management 2019 Report
The Salmonid Enhancement Program (SEP) maintained a Chum and Pink database of mark (fin clips with or without CWTs) recapture information until 2009, at which point reduced capacity and changing priorities in the program resulted in chum sampling data not being compiled in the standardized database for regional analysis. The Chum and Pink database reports annual contribution to catch and escapement for fin clipped chum and pink stocks, allowing estimation of survival and exploitation rate metrics, used to adaptively manage annual hatchery and spawning channel chum production. Currently historical biostandards are used to estimate production levels needed to meet fishery objectives.
This project proposes to compile missing years (2010 to present) of chum fin clipped release data from historical data in the Enhancement and Planning database (EPAD), clip observations in fisheries (Fraser River, Johnstone Strait, Central Coast) from J.O. Thomas sampling, and clip observations in escapement from hatchery sampling programs, using the SEP Chum and Pink database, where analysis can provide assessment metrics, and allow QA and reporting for all years.
Specifically, this proposed work will improve chum escapement and exploitation rate assessments by publishing historical enhanced contribution estimates in fisheries and escapement, based on fin clip rates observed in sampling. This should aid chum run reconstruction analyses by providing estimates of exploitation for Vancouver Island and Fraser River marked enhanced stocks.
S19-SP32 Enhanced Chum Data from 1980 to 2018 Return Years 2019 Report
Quantifying spatiotemporal change and variability in natural mortality and other population parameters (growth, productivity, etc.) is essential for developing reliable forecasting and assessment models used to manage salmon stocks. Productivity of numerous coho salmon populations in the eastern Pacific has decreased since the 1970’s (Zimmerman et al. 2015), and recent research has identified several factors that may be causing increased mortality in both the marine (Thomas et al. 2017) and freshwater environments (Feist et al. 2017; Ohlberger et al. 2018a). However, there has been minimal effort to incorporate these findings into a rigorous modeling approach that can be used for multiple coho stocks to address fishery, conservation, and ecosystem concerns. We propose to develop spatially explicit hierarchical models for coho salmon stocks, ranging from Oregon to British Columbia. These models will be complete life cycle models, allowing us to evaluate the relative contributions of different factors in space and time.
A better understanding of how drivers such as environmental variation, ecosystem interactions, and fishing pressure have changed over time will also allow us to forecast likely scenarios of future change. By modeling the stocks jointly, and including information about both freshwater and marine drivers of productivity, we aim to address Southern Panel Priority # 3, improving “abundance forecasting and escapement estimation for Coho Management Units (MUs), including better understanding of the impacts of environmental variability and uncertainty.”
We propose the development of a bilateral CAN-US Coho Salmon single nucleotide polymorphism (SNP) genetic baseline as the foundation for identifying Coho Salmon stocks in mixed stock fisheries. The primary application of the SNP baseline is to identify the origins and contributions of Coho Salmon populations in Southern Boundary Region mixed fisheries to support international and local Coho Salmon fisheries management and conservation. The same SNP panel would have many other uses, for example, for parent-based tagging to identify hatchery and wild interactions, and as a conservation tool.
S19-SP07A & B Coho Salmon GSI: SNP baseline development 2019 Report
It is becoming increasingly difficult to rely on multi-strand nets for the Round Island gill net test fishery. Manufacturers are not making a lot of 60 mesh multi-strand (MS60) nets anymore as the demand from industry is focussed on 90 mesh Alaska Twist (AT90) nets. Given the latter information and the low inventory of net material, we are proposing to conduct a four year study to compare the relative catchability of Fraser River Sockeye in the Round Island gill net test fishery using a MS60 versus an AT90 gill net.
The objectives of this study will be to compare the trends in selectivity, catchability and catch composition by set for the AT90 and MS60 nets.
The outcomes from this study would be:
– Replacement of the current multi-strand gill net with an Alaska Twist gill net; and
-Calibration of the catchabilities for the Alaska Twist net based on historical catchabilities of the multi-strand net.
S19-FRP05A Comparison of Sockeye Salmon catch and catch rates of two test-fishing gill nets used at Round Island in 2019 Report