Not knowing if you were fishing in a river or not ( fresh/brackish water being pumped in) I'd agree it is a water flow problem....too much turn over can also kill bait fish... almost as quickly as not enough turn.... a complete turn over once every 7 minutes is ideal... faster than that and the bait can become disoriented and stop swimming, which in the case of mackerel means they die.. I'm sure water temp as not an issue, but in warmer times, i float a jug ( or two) of frozen water ( the cap to the jug is siliconed on) and using the recirculating pump can keep Mac's caught at sunset alive until morning.....
|