Science Follow-up: Big (Male) Bass Spawn Earlier

As a follow-up to the discussion around larger male bass spawning first from today’s post, and that this is an overall positive for producing a healthier population of large fish (at least in bluegills, as mentioned). Keeping in mind that there are no absolutes when it comes to bass biology and behavior, there’s a lot of scientific literature that suggests big bass spawn earlier, especially males. I wanted to provide a fairly detailed listing of studies in this regard, along with snippets of statements from the research.

 

Ridgway, M. S.. B. J. Shuter, and E. E. Post. 1991. The relative influence of body size and territorial behaviour on nesting asynchrony in male smallmouth bass, Micropterus dolomieui (Pisces: Centrarchidae). Journal of Animal Ecology 60:665-681.

“Much of the observed variation in timing of nesting was explained by a consistent relationship between the size of individual males and their thermal history (number of degree-days above 50 F) immediately prior to nesting: larger males accumulated fewer degree-days prior to nesting than smaller males. Larger females also appeared to spawn earlier than smaller females.”

 

Baylis. J. R.. D. D. Wiegmann. and M. H. Hoff. 1993. Alternating life histories of smallmouth bass. Transactions of the American Fisheries Society 122:500-510.

“Larger males nested and spawned earlier in the season than smaller males, a finding also reported for a Canadian population of smallmouth bass by Ridgway et al. (1991).”

“…However, the older, larger fish made nests almost entirely in the first half of the season; nests constructed in the last half of the season were defended by small 3- and 4-year old fish.”

“(1) Large males spawn earlier within a breeding season than small males, and are generally older than small males. We have observed this relationship for male smallmouth bass in Nebish Lake (Figures 2-4; Table 2), and other workers have documented the same relationship in populations of smallmouth bass and largemouth bass Micropterus salmoides under both field and experimental conditions (Carlander 1977; Ridgway et al. 1991; Goodgame and Miranda 1993).”

 

Mirandaa, L. E.. and R. J. Muncya. 1987. Recruitment of Young-of-Year Largemouth Bass in Relation to Size Structure of Parental Stock. North American Journal of Fisheries Management 7:131-137.

“The proportion of body weight contributed by the ovaries – the maturity index – was used to examine the relationship between time of spawning and size of the parents for largemouth bass (Micropterus salmoides) in two Mississippi reservoirs. The maturity index increased before the fish spawned, reached a maximum, and then decreased as eggs were released. The maximum was interpreted as occurring at the onset of spawning. A plot of maturity index against time, according to size group, indicated that the larger fish attained a higher index and spawned first.”

“We postulate that largemouth bass populations with large adults can start spawning earlier and produce larger fingerlings that are better prepared to become piscivorous when prey fish begin to hatch.”

 

Goodgamea, L. S.. and L. E. Mirandaa. 1993. Early Growth and Survival of Age-0 Largemouth Bass in Relation to Parental Size and Swim-up Time. Transactions of the American Fisheries Society 122:131-138.

“Larvae spawned by larger adults had significantly more daily rings on the same sampling date than larvae of smaller parents, indicating that larger adults spawned earlier.”

“Our results suggest that protecting the larger adult largemouth bass may advance the average time of spawning in a population, thus increasing the length attained by young at the end of their first year and possibly their recruitment to age I.”

 

A. J. Gingerich and Suski, C. D. 2012. The role of progeny quality and male size in the nesting success of smallmouth bass: integrating field and laboratory studies. Aquatic Ecology 45:4:505-515.

“Nesting male smallmouth bass that successfully reared their offspring to independence spawned earliest in the nesting period were the largest individuals, and guarded eggs with greater concentrations of cortisol compared to males that abandoned their offspring prematurely.”

 

Finally, a study that researched the physiological reasons that might explain the theory of why larger fish, bass included, seem to spawn earliest.

 

Cargnellia, L. M.. and M. R. Grossa. 1997. Fish Energetics: Larger Individuals Emerge from Winter in Better Condition. Transactions of the American Fisheries Society 126:153-156.

While their study couldn’t discern between the two most likely scenarios of what might be happening, either one, or some combination of both, results in the same outcome.

• Bigger fish just store more “fat” energy (technically “lipids”, which have 2X more energy per unit of weight as compared to either proteins or carbohydrates).
• Bigger fish, from a metabolic standpoint, simply deplete less energy stores than smaller fish do over the course of the winter – they live more efficiently from an energy use perspective.

There are a few other scenarios in play, most all of which the researchers were able to sufficiently feel they could discount due to their exacting methods, but which are interesting none the less due to their anecdotal relationship most bassers have probably experienced.

“Larger individuals may feed during the winter” – While it has generally been believed/accepted that bass metabolism slows down to the point of minimal if not totally ceased feeding during the coldest water periods, we have all caught or know of plenty of bass taken through the ice or during partially iced conditions, somewhat discounting this theory. These fish are usually “keeper” sized or better individuals.

“Larger individuals may begin feeding earlier after ice break than smaller individuals” – Again, those who start their bass season immediately after ice out will relate that some of the biggest fish are caught earliest in the year, and that in general, very few small bass are taken during this time.

“Larger individuals face less predation risk. They may consume more prey items than do smaller individuals, and thus build up a greater energy reserve prior to the winter…” – It’s the old axiom of eat or be eaten. If you’re big, you have much less risk of being eaten, and hence can feed more freely or frequently without fear of negative repercussions, e.g., ‘If you can’t run with the big dogs, stay on the porch’ (and possibly starve).’