by Erin Loury, Ichthyology Lab
The fishing practice of bottom-trawling, which involves dragging a weighted net across the seafloor to scoop up deep-dwelling fish, has some obvious downsides: the net often indiscriminately collects everything else in its path. Despite its potential destructive consequences to marine habitats, scientists sometimes use trawling on a small scale as a collection method, and to survey what animals are present in deep areas that are otherwise hard to access.
This haul from a government fishing survey near southern California yielded a bonanza of basket stars, a type of brittle star with many branching arms. You can also spot rockfishes, urchins, crabs and sponges amongst the catch. Though trawling may clear a swath of the seafloor, there are few other means to collect deep-sea animals to inspect an study them. Advances in underwater robotic technology provide one avenue for less destructive studies.