Dataset Information

The fishing and natural mortality of large, piscivorous Bull Trout and Rainbow Trout in Kootenay Lake, British Columbia (2008-2013).

ABSTRACT: BACKGROUND:Estimates of fishing and natural mortality are important for understanding, and ultimately managing, commercial and recreational fisheries. High reward tags with fixed station acoustic telemetry provides a promising approach to monitoring mortality rates in large lake recreational fisheries. Kootenay Lake is a large lake which supports an important recreational fishery for large Bull Trout and Rainbow Trout. METHODS:Between 2008 and 2013, 88 large (?500 mm) Bull Trout and 149 large (?500 mm) Rainbow Trout were marked with an acoustic transmitter and/or high reward ($100) anchor tags in Kootenay Lake. The subsequent detections and angler recaptures were analysed using a Bayesian individual state-space Cormack-Jolly-Seber (CJS) survival model with indicator variable selection. RESULTS:The final CJS survival model estimated that the annual interval probability of being recaptured by an angler was 0.17 (95% CRI [0.11-0.23]) for Bull Trout and 0.14 (95% CRI [0.09-0.19]) for Rainbow Trout. The annual interval survival probability for Bull Trout was estimated to have declined from 0.91 (95% CRI [0.76-0.97]) in 2009 to just 0.46 (95% CRI [0.24-0.76]) in 2013. Rainbow Trout survival was most strongly affected by spawning. The annual interval survival probability was 0.77 (95% CRI [0.68-0.85]) for a non-spawning Rainbow Trout compared to 0.41 (95% CRI [0.30-0.53]) for a spawner. The probability of spawning increased with the fork length for both species and decreased over the course of the study for Rainbow Trout. DISCUSSION:Fishing mortality was relatively low and constant while natural mortality was relatively high and variable. The results indicate that angler effort is not the primary driver of short-term population fluctations in the Rainbow Trout abundance. Variation in the probability of Rainbow Trout spawning suggests that the spring escapement at the outflow of Trout Lake may be a less reliable index of abundance than previously assumed. Multi-species stock assessment models need to account for the fact that large Bull Trout are more abundant than large Rainbow Trout in Kootenay Lake.

SUBMITTER: Thorley JL

PROVIDER: S-EPMC5228508 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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The fishing and natural mortality of large, piscivorous Bull Trout and Rainbow Trout in Kootenay Lake, British Columbia (2008-2013).

Thorley Joseph L JL Andrusak Greg F GF

PeerJ 20170110

<h4>Background</h4>Estimates of fishing and natural mortality are important for understanding, and ultimately managing, commercial and recreational fisheries. High reward tags with fixed station acoustic telemetry provides a promising approach to monitoring mortality rates in large lake recreational fisheries. Kootenay Lake is a large lake which supports an important recreational fishery for large Bull Trout and Rainbow Trout.<h4>Methods</h4>Between 2008 and 2013, 88 large (≥500 mm) Bull Trout a ...[more]

PMID: 28097071

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Project description:Gynogenetic development in fish is induced by activation of eggs with irradiated spermatozoa followed by exposure of the activated eggs to the temperature or high hydrostatic pressure (HHP) shock that prevents 1st cell cleavage. Produced specimens are fully homozygous fish also known as Doubled Haploids. Gynogenetic DH individuals might be used aquaculture and developmental biology unfortunately; the potential application of DHs is limited by a rather low survival rate of such specimens. However, observed variation in the survival rates of the gynogenetic embryos originated from different clutches suggests that eggs from some females have increased ability for gynogenetic development than others. Taking into account that first 10 cell cleavages in the fish embryos rely on the maternal RNA, it is tempting to assume that the ova showing such a vast difference in potential for gynogenesis may have also had different biological characteristics including alterations in maternal gene expression profiles. If so, then genes that up- or down –regulated expression in eggs increases competence for gynogenetic development in trout might be considered as candidate genes for gynogenesis in rainbow trout. Thus, the main goal of the project is identification of genes that increase ability of rainbow trout eggs for gynogenetic development. Within the project, we tried to verify following hypotheses: 1. Eggs from different females have different potential for gynogenesis in rainbow trout. 2. Eggs with different ability for gynogenetic development with all maternal inheritance have different biological characteristics including morphology and anti-ROS enzyme activities. 3. Eggs with increased competence for gynogenesis have altered transcriptomic profiles. 4. There are some particular genes that altered expression in trout eggs enable development of gynogenetic embryos. Gynogenetic rainbow trout specimens were produced in the course of activation of eggs with UV-irradiated spermatozoa and High Hydrostatic Pressure shock (HHP) applied around 1st cell cleavage. Eggs from several females were used in the experiment. Survival rates of gynogenetic rainbow trout was monitored since fertilization. Quality of eggs was examined by assessment of their morphology and activity of anti-ROS (reactive oxygene species) enzymes. Transcriptome of eggs showing increased and decreased developmental competence for gynogenesis was analyzed using RNA-seq approach and results compared to find out any alterations related to survival of gynogenetic trout.

Dataset Information

The fishing and natural mortality of large, piscivorous Bull Trout and Rainbow Trout in Kootenay Lake, British Columbia (2008-2013).

Publications

The fishing and natural mortality of large, piscivorous Bull Trout and Rainbow Trout in Kootenay Lake, British Columbia (2008-2013).

Similar Datasets

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