Movement past hydroelectric dams and related in-river structures has important implications for habitat connectivity and population persistence in migratory fish. A major problem is that many of these structures lack effective fish passage facilities, which can fragment spawning and rearing areas and negatively impact recruitment. While traditional fish passage facilities (e.g., ladders, trap and haul) can effectively enable fish to pass over barriers, their capital or operational costs can be significant. We evaluated the utility of a novel transport device that utilizes a flexible tube with differential internal air pressure to pass fish around in-river barriers. A total of N = 147 adult fall Chinook salmon (Oncorhynchus tshawytscha) nearing maturation were apportioned to three treatments and a control group. In two of the treatments, adult fall Chinook salmon were transported through the device via two lengths of tube (12 or 77 m) and their injury, stress, and immune system responses and reproductive function were compared to a third treatment where fish were moved by a standard trap and haul method and also to a control group. We observed no significant differences among the treatment or control groups in post-treatment adult survival, injury or stress. Indicators of immune system response and reproductive readiness were also not significantly different among the four groups. Egg survival was significantly different among the groups, with the highest survival in the eggs from females transported 77 m and lowest in the control group; the differences were highly variable within groups and not consistent with the duration of treatment or degree of handling. Taken together, the results suggest the device did not injure or alter normal physiological functioning of adult fall Chinook salmon nearing maturation and may provide an effective method for transporting such fish around in-river barriers during their spawning migration.
Supplemental_Data_JFWM-108R
Table A1. The results of a fall Chinook salmon (Oncorhynchus tshawytscha) passage and handling study conducted in November, 2014, at the Priest Rapids Salmon Hatchery, Mattawa, Washington. Each adult salmon was given a Passive Integrated Transponder (PIT) tag with a unique identification code (column: PIT tag number). Their gender was determined (column: Sex with M = male and F = female). Fork length was measured in cm (column: Length), body circumference was measured in cm (column: Circumference), and body weight taken in kg (column: Weight). Fish were divided into one of four treatment groups (column: Treatment) – Whoosh Fish Transport System (WFTS) 77 m tube (WFTS-77), WFTS 12 m tube (WFTS-12), trap and haul (T&H), or control. Treatment dates (column: Treatment date) ranged from November 4-6, 2014 and mortality dates (column: Mortality date) ranged from November 4-11, 2014. The following information was collected on a subset of fish – column: Spleen IL1-β normalized with 18s (n = 65); column: Spleen IgM normalized with 18s (n = 65); column: Cortisol concentration (ng/mL) (n = 41); column: Day 3 vitellogenin concentration (mg/mL) (n = 63); and column: Percent epithelial injury (%) (n = 42). In all columns, NR represents no data were recorded.
Table A2. The gamete survival results from a study on the effects of passage and handling conducted in 2014 with adult fall chinook salmon (Oncorhynchus tshawytscha) that were captured at Priest Rapids Salmon Hatchery, Mattawa, Washington. Each fish was given a Passive Integrated Transponder (PIT) tag with a unique identification code (column: PIT tag number). Fish were divided into one of four treatment groups (column: Treatment) – Whoosh Fish Transport System (WFTS) 77 m tube (WFTS-77), WFTS 12 m tube (WFTS-12), trap and haul (T&H), or control. Their gender was determined (column: Sex with M = male and F = female). One female’s eggs were fertilized with sperm from one male (column: Pair number) for a total of 37 pairings (i.e., sib family). The fertilized eggs were divided into three sub-samples per family (approximately 100 eggs per sub-sample) and randomly assigned to a stack, tray and cell in vertical flow incubators. Fertilized eggs were held in incubation trays at ~10°C until they reached the eyed egg stage (December 17, 2014, or approximately 40 days post-fertilization), at which time the number of live and dead eggs were counted to determine gamete survival by cell (columns labeled 1st cell survival, 2nd cell survival, and 3rd cell survival, all percentages). Data analysis was done on the average embryo survival to the eyed stage (subsamples were averaged per sib family) (column: Average survival %).
