Very interesting.
I have been gathering info on the single spawn idea and forwarding to Dave.
This is one area where I think there are big differences as well as some similarities in northern vs southern ponds in a " rolling latitudinal effect"
I have no doubt of there being multi-spawns in the south based on observations and published material including fisheries manuals by the biologists of a number of states. Even the Neff article quote below from the longhair post showes that there were at least a few multi-spawners in his studies which occured in Ont. Canada. I do think that Dave is on to something in northern ponds based on other studies including the Neff ones and that there is likely one longer rolling spawn in many northern ponds. I also think that even in the south there are some rolling spawn elements with late maturing or small or poorer conditioned fish and while there are multi-spawns all do not spawn at the same time or the same # of times.
Theo I use to be very skeptical about moon phase matters and still am in many areas but not wrt BG/RE spawn. I have observed it to much in our ponds and had to many fisheries biologists confirm it in this area. From 10 years of observation notes the first spawn BG/RES (overlaping) of the year is the first full moon (usualy March)after the water temps get high enough. There are then ebbs and flows in BG spawning with max spawn activity on the full moon in May (or early June depending on what time of mth they fall) If you come back to observe 10 days after the full moon there is very little activity in comparison. There is an obvious ebb and flow but no 100% point (where all are spawning or not or are on or off the beds). As the full moons of Mar.-Aug. ( ? Sept. late spawners) approaches BG spawning maxs. then declines. Same for entire spawn - it starts slow in March - maxs in May/June and wanes through Aug/Sept. However in the studies I have read from northern ponds I have never seen this type of activity (multi-spawns or full moon) discussed or refered to or mentioned and my guess is it does not happen in northern waters or scientists of this caliber would have noted it. ewest
Neff study ppg 283.
Repeat spawning
To ascertain if repeat spawners showed consistency in their nest
position, in the years 1988�1990, 1993 and 2002 a total of 901
parentals were tagged using Floy brand T-tags inserted into the
muscle directly below the dorsal fin on the left side of the body.
The study site was monitored for the duration of the spawning
season and the nest position of repeat spawners was recorded. In
most cases in which males spawned a second time in a breeding
season they were not remeasured. Thus, while we had repeat
measures of nest position, we did not have a second estimate of egg
score, male length, condition or ear tab area.
pg. 384
Of the 901 tagged males, 119 (13%) nested a second
time during a single breeding season (Table 3). Seven of
115 males (6%) that nested colonially in their first
breeding attempt switched to nest solitarily in their second
breeding attempt, and none of the 4 males (0%) that
nested solitarily in their first breeding attempt switched to
nest colonially.
Neff link
http://publish.uwo.ca/%7Ebneff/papers/Solitary_nesting_in_bluegill.pdf Longhair link
http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=20;t=002154;p=1 PS : Bruce may well be right that a large part of the difference may be genetic differences developing over a long periods of drift/mutation/selection. If so I wonder if the north-south continuum of ranges of difference occurs from and based on the latitudinal seperation.
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