For the record I am not a biologists, vetinarian, rocket scientist or anything like that, chances are I probably didnt even spell some of that right.I do however spend alot of time on the water and for the last 3 years I've made it my goal to try to figure out when excactly the spawn occurs.This is just my opinion and by no way shape or form does that mean its right.I just want to make that clear.I'm just tryin to put information out there to hopefully help somebody. The 2 primary lakes that this info is based on is Greenwood and Monticello but its real similar on other lakes in SC too.The 2 species is blues and channels which are very similar in spawning habits and times.I hadnt had alot of time to observe flatheads. PRE-SPAWN Most of the spawning information you read in articles and biologists reports are based on channel cats, theres not much studies on blues and flatheads spawning habits.I have found that blues are very similar to channels though. Catfish have one of the longest prespawn periods of any freshwater fish in the USA. One of the best indications that the spawn is getting close to starting is when most of the bigger fish (channels 6 lbs and up and blues 15 lbs and up) are predominately males.Usually when the daytime water surface temp is between 68 to 75 degrees.The males are the first to start feeding because they are the ones that find the spawning areas and the ones that stay and gaurd the eggs and young. The males of both blue and channels have big heads in other words their heads look to big to be on their body.Their bodies are usually thin at this time but often thru-out the year too.The muscles or glands on the top of their heads will start to swell and look like 2 knots on each side.The male blue will start to turn an even darker blue than they already are.Their lower jaw, barbels and the upper part of their their body will all turn darker so will the channels. Male channel cats are really confusing thru all seasons.Some will have a light blue or gray color (often mistaken to be a blue) all year and some will have a golden brown color while not during spawning time.During the pre-spawn or attracting time they will all turn blue and some very dark blue almost black, even the golden brown ones. Both male blue and channels will remain this color thru-out the whole spawning period.You will start to see scares and scratches on them as they are rooting around and fighting for territory. After a few weeks the fat females will start to dominate the catch because they will be feeding heavy before going on bed.By this time the males have found their spawning areas and are now trying to attract the feeding egg filled females.These temperatures will fluctuate from hot days and cold nights but this usually occurs when the daytime surface temp is around 75 to 78 degrees. The fishing can be really good at this time. SPAWN Slow fishing (no big males or females) usually indicates the spawn is on heavy.This seems to occur when the daytime surface temp is 78 to 85 degrees.Not all fish will spawn at the same time so a big location change on the lake might put you right back into prespawn action.I have found that while fish may be spawning in a feeder creek and in pre-spawn in a feeder creek 4 miles down the lake. POST-SPAWN The post spawn can be some really good fishing also, often times better than prespawn.The females will be the first to start feeding, while the male stays on the bed and stands gaurd.When the females first come off and start feeding they will be fairly skinny.Some will have a few bite marks and scares but not as badly as the males.This period dont seem to last to long.Not quite sure why. A good indication that the spawn is pretty close to over is when the males start to dominate the catch again.Most of them will look like they have been run thru a meet grinder.They will still remain dark colored but very very scarred up from fighting and very thin.You will still catch females but the males seem to dominate the catch. The surface temps are usually above 85 degrees by this time. PRE-SUMMER The females are usually back to their fat and healthy self by now.The scares on the males will be starting to heal and the regular summer pattern will set in. THE AVERAGE TIMES THIS HAPPENS FOR THE LAST 3 YEARS The pre-spawn on both Greenwood and Monticello seem to be from April to late May. The spawn is usually from late May till early July. The spawn is usually completely (all fish) over by mid July.Although I have caught males with fresh scarres on them as late as August especially last year 2007. Keep in mind not all fish spawn at the same time on the same lake so this I think is why the catfish spawn is such a wide gap of time. All the surface temps that I listed are not precise, they can vary a few degrees up and down.Keep in mind that just because the surface temp is one thing that dont mean that the water 2 foot or 20 foot below the surface is the same.The temps also need to be steady for several days before fish are triggered.Lots of times in late March the surface temp might be low 70's one day and high 60's the next.This is not a good gage of when fish could be triggered. PICTURES I've cropped for closer veiwing and attached several pictures of pre and post spawn male blues and channels.Some of the pics are not that great of quality but its the best I got.I will have to use 2 posts to get them in. Pre-spawn pic #1- This is a male channel cat already starting to turn very dark on the top but still golden brown on the sides.The glands on the top of his head are also starting to swell up. Pre-spawn pic #2- This is a male blue that is just starting to feed and change colors.Notice the thin body and very dark blotchy color it is turning. Pre-spawn pic #3- This is another male blue thats startin to get dark.Notice the way his lips and barbels are starting to get really dark blue.The muscles or glands are not quite swelling up yet though.That gives me the inclination that he is just starting his pre-spawn feeding. More pics in the 2nd post.