Fishing: Dolphins under threat when lines and plastic rubbish discarded in ocean

Dolphins are common around our coast and will die if they become tangled in lines or nets. Picture / Geoff Thomas

The things you see out on the ocean. A couple of friends, who shall be referred to only as Tim and Paul because the Department of Conservation may want to talk to them, were returning recently from a day's fishing chasing snapper and kingfish in the Bay of Plenty. They had one kingfish in the boat, and were heading back to Whangapoua.

"We were halfway across from Great Merc [Mercury Island] when we saw something bobbing in the water," reported Tim. As they came closer they realised it was a dolphin. It was hanging in the water, straight up and down, with its beak just on the surface. And there was a baby dolphin swimming round and round it," he added.

The poor creature was tangled in what appeared to be a bunch of long line.

"It looked as if somebody had bunched up the line and cut the hooks off, then thrown it away, and the dolphin was caught up in it and was helpless. We pulled it in and cut away the line, and it recovered and swam away. But that was one lucky dolphin. Another half an hour, and it would have drowned. And if we had been passing even 20m further away, we would never have seen it. It was an amazing experience, and my mate said he felt quite emotional afterwards."

Their experience is a stark lesson in the danger of discarding anything in the water that is not natural. Whether it was intentional or not, the unwanted fishing line finished up floating around in the sea. And the fact that the hooks had been cut off and the amount of line involved suggested it had come from a commercial fishing vessel.

But such debris poses a serious threat to marine life and bird life. One of the biggest dangers to wildlife in the oceans is plastic material - plastic bags, containers, or can holders.

Plastic takes up to a million years to break down in the environment, and birds and marine mammals often become entangled in it.

Other animals like turtles and whales ingest it, while mistaking it for natural food like jellyfish. It does not take much imagination to see how a half submerged plastic bag could appear similar to a jellyfish drifting in the currents. And if the material builds up in the stomach of such animals, it can eventually be fatal.

Most people who spend time on the ocean are aware of such dangers and would never intentionally throw rubbish into the sea, but it can happen quickly if the wind catches an empty bait bag. A long-handled gaff within handy reach can be used to quickly snag the offending bag, or a weighted hook or lure cast over it will catch it.

Another, more common, serious threat comes from nets set for fish, particularly if they break free in a storm and are lost. Such nets are called ghost nets, and when giant commercial nets are lost at sea they pose a huge threat to all life as they may drift on ocean currents for many years.

Freshwater

Cicadas have finally started hatching in the back country, but the insects will be more active on a sunny day. This is the time of the season that dry fly anglers wait for and a large floating cicada imitation will be smashed in an explosive rise as the trout attack them. It also works when fishing rivers like the Tongariro River and other Lake Taupo tributaries; and also on lakes like Otamangakau and Aniwhenua where insects form a large part of the trout's diet. In fast-running water the fly is cast out and allowed to float down the current, but on the surface of a calm lake the fly should be twitched to imitate a struggling cicada.

Tip of the week

Looking after your tackle is important if you want it to perform properly and last. The salt in seawater is corrosive and can quickly affect the performance of metal in reels and rods. Rods and reels should be washed down with freshwater, but first tighten the drags on reels to prevent water being forced inside, and don't use water under pressure. Then spray all over with a protective spray, and loosen the drag before storing. The washes in the drag systems will be damaged if left under tight pressure for long periods. After several outings handles and spools on reels should be removed and the correct grease applied. Corrosion can also build up under the reel seat when reels are left attached to rods for long periods, so they can be removed and spray applied regularly.

The rings on a rod can also cause problems through wear and tear, particularly the tip ring when swivels are continually banging on the ring when the line is wound in. This can cause fine cracks if the ring has a ceramic liner, and the symptom of this problem is a fine web of shredded line which puffs up at the end of the rod. This damages the line and the ring should be replaced. To check for this problem run a length of nylon stocking through the ring and if there is a crack it will tear the material. Another way to prevent this is to put a plastic bead above the swivel on your line, and the bead will hit the ring first when the line is wound in tightly.

Bite times

Bite times are 6.35am and 7pm today, and 7.20am and 7.40pm tomorrow. More fishing action can be found at GTTackle.co.nz.