For once and for all, is it detrimental to swim a few times a week in the midst of a weight-training schedule (a bulking-up regimine)?
How about amidst a toning-up regimine?
depends. I’d think the weights would make you sink to the bottom.
For bulking: I would try to do it as far from lifting as possible, time-wise. Recovery is important and rigorous swimming would be detrimental to recovery. However, you could take your shake and sugar after you lift and go out for a light swim. This actually would be good, increasing, or sustaining blood flow to get the nutrients where they need to be and flush out any lingering acids or ammonia that might be still in the muscles. A good cool down too for the joints and a good stretch which some people think is good too.
Do this and see if your soreness decreases.
For toning: I would think rigorous swimming on top of weight training while cutting would be too much of a muscle “burning” activity, what with the calorie deficit and all. Work the muscles and keep as much strength as you can and leave them alone while that fat drips off.
Oh man that made me laugh! Thanks for that. 
Interesting info Fuel. I like to swim sometimes after the gym, I find it a good warm-down. Guess it depends how vigourously you swim?
One thing that’s interesting is that swimming causes your metabolism to spike. It’s theorized that this is because you’re working in water that’s generally about 20[sup]o[/sup] F colder than you.
Check this out for more detail.