Large differences in catch per unit of effort between two minnow trap models

Abstract

BackgroundLittle is known about variation in catch per unit of effort (CPUE) in stickleback fisheries, or the factors explaining this variation. We investigated how nine-spined stickleback (Pungitius pungitius) CPUE was influenced by trap model by comparing the CPUEs of two very similar minnow trap models fished side-by-side in a paired experimental design.ResultsThe galvanized trap type (mean CPUE = 1.31 fish h–1) out-fished the black trap type (mean CPUE = 0.20 fish h–1) consistently, and yielded on average 81% more fish.ConclusionsThe results demonstrate that small differences in trap appearance can have large impacts on CPUE. This has implications for studies designed to investigate abundance and occurrence of fish using minnow traps.

On the Status of Threespine Stickleback (Gasterosteus aculeatus Linnaeus 1758) in Lake Bracciano, Italy

“…Despite being historically present in the Lake Bracciano catchment [11], we did not find a single threespine stickleback using capture techniques that are commonly used to collect stickleback [14] and that were successful to retrieve specimens in three other Italian watersheds (Tiber, Garigliano, Tagliamento) during the same sampling campaign. Adult stickleback may, however, have existed in parts of the lake that were not rigorously assessed, i.e., the pelagic and the deeper vegetated part of Lake Bracciano [15].…”

“…We used metallic minnow traps (Dynamic Aqua-Supply Ltd., Surrey, BC, Canada), which are commonly used to collect stickleback quantitatively [14], to probe the littoral zone of Lake Bracciano during breeding season. Each trap had a mesh size of 6.35 mm, being 42 cm long, maximum 22.9 cm wide with an entrance hole of 2 cm diameter.…”

Comparison of catch per unit effort among four minnow trap models in the three-spined stickleback (Gasterosteus aculeatus) fishery

“…While trap model – but not baiting – was found to have a significant influence on CPUE, only two different collapsible canvas trap models were used in that study 16 . Similarly, several studies on nine-spined sticklebacks have verified CPUE differences among different trap models 15 17 18 . Moreover, the results from these independent studies indirectly suggest that the collapsible canvas traps and the metallic Gee-type 19 minnow traps might differ in their CPUE.…”

“…Yet, little research has been conducted in comparing the efficiency of different fishing methods in catching sticklebacks (but see refs. 15 , 16 , 17 , 18 ).…”

“…Earlier studies on stickleback CPUE have focused on comparisons of different trap models and baiting on nine-spined stickleback ( Pungitius pungitius ) catches 15 17 18 . In the only study focused on three-spined sticklebacks, Merilä 16 investigated the effect of baiting and trap model on CPUE in the brackish-water environment of the Baltic Sea.…”