Does sight fishing hurt largemouths?
For some bass anglers, sight fishing for bedding bass is the ultimate rush. Other anglers consider bed fishing unsportsmanlike, with some asserting it adversely affects bass abundance.
So which group is right?
Beginning more than a decade ago, a small group of biologists investigated the effects of catching nest-guarding male bass and determined that bed fishing affects production of young from individual bass nests.
Here is a recap of the evidence from multiple research studies that found adverse effects of bed fishing or, more specifically, the effect of removing the guarding male from a nest of fertilized eggs of recently hatched fry:
When a bass is removed from the nest, untended eggs and fry are often eaten by predators. The longer the guarding male is gone, the more offspring are lost to predators.
A caught bass that is immediately released resumes its guardian duties. The longer a bass is played or the longer it is exposed to air (for example, to admire or to take a picture), the slower the bass is to return to the nest after it is released.
A caught bass that is displaced (for example, caught in a tournament and released at the weigh-in site) often returns to the nest, but the time to return increases with the distance the fish is moved from the bed.
The “guardianship” of the male bass — how aggressively and effectively it defends the nest and its contents — decreases as the brood size diminishes. If the brood size is heavily depleted by predators, the male bass might abandon the remaining brood.
These effects are clear, but they are effects on individual nests.
Many management biologists have countered that healthy bass populations have many spawning bass, so success or failure of an individual nest — or even a bunch of individual nests — might mean little at the level of the entire population.
Although the persistence of bass populations despite heavy bed fishing on some lakes suggests bed fishing is not an issue, the effects of bed fishing on bass populations has not been measured.
A recently completed study in Florida takes managers a step closer to understanding the effect of bed fishing on bass recruitment.
A team of Florida Fish and Wildlife Conservation Commission biologists headed up by Nick Trippel evaluated the effect of controlled bed fishing on Florida bass in one-acre ponds at Richloam Fish Hatchery in Central Florida.
Ten male and 10 female Florida largemouth bass bearing easily readable numbered disk tags were stocked into each of nine research ponds. Brush and cinder blocks were added for cover.
The ponds were stocked with bluegill, Seminole killifish and mosquitofish to provide forage for the adult bass and their offspring, and to replicate the presence of potential nest predators.
Nests were located and monitored every other day throughout the spawning season by snorkel-diver surveys to identify the guarding male and record the approximate size of the brood (number of eggs), health of eggs and presence of nest predators like sunfish or crayfish.
Nests were judged as successful if they produced swim-up fry.
In 2013 and 2014, anglers attempted to catch the bedding bass from the marked nest in five ponds; no angling occurred in the other four ponds.
Bass caught from the beds were held for one hour in a net enclosure and then released.
Spawning began in February and continued through May. This protracted spawning season is typical of Florida bass fisheries.
Across both years, 91 nests were fished in the five ponds, and bass were caught off 44 of them. Of the 44 nests from which bass were caught, 21 were successful (produced fry) and 23 were unsuccessful. Across both years and all ponds, 41 percent of the nests produced bass fry in the fished ponds, and 54 percent of the nests produced fry in the unfished ponds.
While there were only small differences in nest success, recruitment — the number of young bass at the end of summer — was the measure of interest. So the ponds were drained in the fall, and young bass counted.
The unfished ponds produced an average of 820 young bass, and the fished ponds produced an average of 518 bass.
The higher number of fish in the unfished ponds was largely a result of collecting almost 3,500 young bass in one unfished pond. Because of the high variability, the difference in young bass per pond between fished and unfished was not statistically significant.
Certainly questions still remain, namely whether these relatively small and simple systems are good indicators of what happens in larger lakes with more complex habitat and fish communities or for bass populations at the northern edge of their range.
But the management implications are clear: Florida fisheries managers see no need for closed spawning seasons or closed spawning areas in Florida. These results probably apply to other Southern largemouth bass fisheries.
