Answer
79 total shark attacks this year (16 more)
Work Step by Step
We know that this year there was an increase in shark attacks by $25.4\%$ (out of 63 last year). We can calculate this amount with a ratio:
$\displaystyle \frac{25.4}{100}=\frac{x}{63}$
Cross-multiply:
$25.4*63=x*100$
$1600.2=100x$
$x=16.002$
$x\approx 16$
Thus this year there were 16 more shark attacks. Therefore, the total was:
$16+63=79$