Purse Seiners & Gill-netters

small purse seiner
A small purse seiner. Note the outboard skiff on the stern, used in setting out the net. The net itself is piled on the back deck. The boat's booms handle both the net and the skiff, while the crow's nest on the mast gives a bird's eye view of operations.
purse seine
Setting out a purse seine

A purse seine net is a complex device with floats at the top and lead weights at the bottom. Often, a skiff is used to draw out the floating net around the fish. The purse line at the bottom of the net is then drawn in, closing it off and trapping the fish. The net is then taken aboard over a large roller, either at the side or the stern. The mesh is usually sized to let small fish escape while retaining large ones.

Most of the purse seining done in New Jersey waters is for Mossbunker, which is used as bait. Mossbunker, aka Menhaden, is also ground up for animal feed and fertilizer, but fishing it for such uses is banned in state waters, which hopefully does something to save our fish from the fleets of huge offshore "bunker boats" that travel the world's oceans vacuuming out the fish. Local seining boats tend to be small.

purse seine

Purse seining like this is also the preferred method of catching tuna and other pelagic fishes. Dolphins that travel with schools of such fishes are often trapped in the nets and drown. Why they don't just jump out is a mystery. In recent years, new methods of purse seining have reduced such unfortunate bycatches.

USNS Shearwater reef
Shearwater, a small freighter converted to a purse-seiner
purse seine
purse seine
purse seine

A sequence of images showing purse nets being set out around a school of fish, closed, and drawn in by a crane on the mothership, and finally vacuumed out into the mothership's holds.

gillnet

Gill netting is a method of fishing in which a net with a specific mesh size is used to ensnare fish of a specific matching size. The fish can swim part-way but not all the way through the net. When it tries to back out, it becomes snagged on its gill covers. Smaller fish pass harmlessly through the mesh, and larger fish are not ensnared. A gill net boat would be similar to a seiner; I cannot tell them apart.


Polyethylene
Polyethylene - the simplest polymer: ---CH2-CH2-CH2-CH2-CH2---

Polymer materials - rubbers, plastics, and silicones - are not really of interest as artifacts. They are, however, among the most important materials to divers: without neoprene, nylon, and a bewildering range of other polymer materials, we would not have most of the equipment that makes diving possible!

Printed from njscuba.net