Ghost Fishing by Abandoned Trotlines in a Simulated and Actual Reservoir

Ghost fishing is described as the continuation of fishing by abandoned fishing gear. The freshwater trotline, a passive gear that is routinely found abandoned, has never been evaluated for its ability to ghost fish. We tested the effectiveness of top-water set trotlines to ghost fish in (1) a simulated reservoir (i.e., hatchery ponds) and (2) an actual reservoir. In our simulated reservoir, we exposed Channel Catfish Ictalurus punctatus to baited and bare (unbaited) hooks of two hook styles (circle and “J”) during the winter and summer seasons. We found that in the simulated reservoir, catch rates of baited hooks (mean = 18.4 fish per 24 hooks, standard error [SE] = 2.13) did not differ significantly from bare hooks (mean = 15.3 fish per 24 hooks, SE = 1.77), circle hooks were 1.5 times more effective at catching fish than “J” hooks (χ² = 4.19, df = 1, P = 0.041), and fish were retained longer in the winter (mean = 12.7 d, SE = 0.66) compared to the summer (mean = 2.8 d, SE = 0.21). We used the actual reservoir portion to examine the long-term fishability and the overall longevity of the trotline gear during the same seasons. Catch was highest during the first week and decreased with time. Trotlines caught mostly fish (81.6%), and most catch (>68%) occurred after the initial bait was lost. Winter-set trotlines captured more organisms (11.6 per 25-hook trotline; SE = 2.05) than summer-set trotlines (5.2; SE = 0.99). Trotline longevity was assessed by counting the fishable hooks through time. Longevity differed between seasons (P = 0.0039), and winter-set trotlines lasted longer (50% hook loss at 52 d, 95% confidence interval [CI] = [49, 77]) than summer-set trotlines (32 d, 95% CI = [24, 36]). This study confirms that abandoned freshwater trotlines do ghost fish and will continue for months after they are initially set.