Muskie Lunacy: does the lunar cycle influence angler catch of muskellunge (Esox masquinongy)?

Mark R Vinson,Ted R Angradi,Shin Yamazaki

doi:10.1371/journal.pone.0098046

Mark R Vinson, Ted R Angradi + Show 1 more

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https://doi.org/10.1371/journal.pone.0098046

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Abstract

We analyzed angling catch records for 341,959 muskellunge (Esox masquinongy) from North America to test for a cyclic lunar influence on the catch. Using periodic regression, we showed that the number caught was strongly related to the 29-day lunar cycle, and the effect was consistent across most fisheries. More muskellunge were caught around the full and new moon than at other times. At night, more muskellunge were caught around the full moon than the new moon. The predicted maximum relative effect was ≈5% overall. Anglers fishing exclusively on the peak lunar day would, on average, catch 5% more muskellunge than anglers fishing on random days. On some lakes and at night, the maximum relative effect was higher. We obtained angler effort data for Wisconsin, Mille Lacs (MN), and Lake Vermilion (MN). For Lake Vermilion there was a significant effect of the lunar cycle on angler effort. We could therefore not conclude that the lunar effect on catch was due to an effect on fish behavior alone. Several factors affected the amount of variation explained by the lunar cycle. The lunar effect was stronger for larger muskellunge (>102 cm) than for smaller fish, stronger in midsummer than in June or October, and stronger for fish caught at high latitudes (>48°N) than for fish caught further south. There was no difference in the lunar effect between expert and novice muskellunge anglers. We argue that this variation is evidence that the effect of the lunar cycle on catch is mediated by biological factors and is not due solely to angler effort and reflects lunar synchronization in feeding. This effect has been attributed to variation among moon phases in lunar illumination, but our results do not support that hypothesis for angler-caught muskellunge.

Highlights

Studies of the effects of the moon on fish behavior have shown that fish spawning [1,2,3,4], vertical and horizontal movement [5,6], migration [7,8], activity [9], feeding [10,11], and vulnerability to commercial [12,13] or recreational fishing [14,15,16] may be synchronized to lunar cycles
Addition of the predictor cosine2h to the nighttime model significantly improved the fit of the model and shifted predicted minimum catch from the new moon to the periods between the full and new moon
In contrast to our findings based on angler-reported catches, we found no lunar effect on muskellunge Catch per unit of effort (CPUE) from creel surveys

Summary

Introduction

Studies of the effects of the moon on fish behavior have shown that fish spawning [1,2,3,4], vertical and horizontal movement [5,6], migration [7,8], activity [9], feeding [10,11], and vulnerability to commercial [12,13] or recreational fishing [14,15,16] may be synchronized to lunar cycles. The idea that fish-feeding behavior is related to the phases of the moon was popularized, if not quite quantified, by John Alden Knight in 1936 with the publication of his ‘‘Solunar’’ tables [17]. Lore has accumulated around muskellunge behavior, a central theme of which is the role of moon phases on the species’ feeding activity and catchability

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