Fig. 5. Bulk water absorption rate correlated to net strong ion absorption rate (sum of net Na⁺ and Cl^– flux rate) across killifish intestine, in brackish water (BW, 10% seawater; grey squares) and at several time intervals after transfer to fresh water (FW; black triangles and diamonds). Bulk water transport was extremely well correlated to net ion transport (r²=0.960, P<0.0001), with a slope of 0.00342±0.00010 ml water per µmol strong ion. Grey broken curves represent 95% confidence limits of the regression.