Dolomedes tenebrosus
(Dark Fishing Spider)

Hi, fishing spiders do hunt fish and tadpoles and other aquatic creatures. They aren’t always near water though, they hunt land animals too. The females carry their eggsacks under their head with their chelacerae. The chelacerae are the parts that hold the fangs. They are thought to carry their eggs to protect them from parasitic wasps. So, the white circle is probably an old insect egg sack, the spider’s would be ball-shaped and a female wouldn’t let go of it and walk away. The parasitic wasps are probably the most dangerous creatures that fishing spiders are evolved to defend against.