Baiting improvesCPUEin nine‐spined stickleback (Pungitius pungitius) minnow trap fishery

Abstract

Whether or not baiting influences stickleback catch per unit effort (CPUE) remains a matter of debate among stickleback researchers: While the opinions about the impact of baiting on CPUE differ, supporting quantitative data are scarce. The effect of baiting and trap type on nine-spined stickleback (Pungitius pungitius) CPUE was studied in a field experiment conducted over four consecutive days in a small pond in northeastern Finland. The results show that baited traps yielded better (mean CPUE = 1.24 fish/trap/d) catches than unbaited traps (mean CPUE = 0.66); however, there were also differences in CPUE depending on the type of collapsible trap that was used. The trap type effect on CPUE seemed to differ among age classes – the finer meshed trap caught more young-of-the-year fish than the coarse-meshed one, whereas the opposite was true for the older and larger individuals. The results agree with those of an earlier more restricted study conducted in the same locality: Together, these results provide strong evidence for the positive impact of baiting on nine-spined stickleback CPUE.

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

“…Individual and other biotic interactions in the wild might influence escape (and entry) probability in a trap model-specific fashion. Nevertheless, whether caused by variation in entry or escape rates, the differences in CPUE among different trap models were clear and consistent with estimates available from earlier studies 15 16 17 18 .…”

“…This is a significant finding, since the performance of metallic and canvas traps has never been directly compared in the stickleback fishery. Several earlier studies have compared the performance of the two canvas trap models, both in three-spined 16 and nine-spined stickleback fisheries 15 17 , and found that the black traps catch more (adult) sticklebacks than the red traps in both species. Hence, the results from earlier studies would encourage the use of black canvas traps over the red ones.…”

“…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.…”