The Angler is since the patch my most used water dino since it can harvest large amounts of silica pearls. Tranq it, feed it raw prime meat (takes alot of narcotics. Pump the points into speed and weight and it will be your silica pearl friend forever!
Be really care when knocking these things out from a distance! Unfortunately they don't look knocked out when they are so continuing to shoot darts at them can be an easy an unfortunate mistake to make.