Guns with Tanks

By Iain A Anderson

While preparing for a dive at Jones Bay north of Auckland, New Zealand, I met a group of four spear-toting scuba divers about to enter the water. This alarmed me for it is extremely unsporting to spear on scuba.

I mentioned this to the group spokesman who assured me that they were just after some kingfish. I thought, ‘well good luck if you can spear one of these fast swimmers’ but ‘don’t spear any slow guys like me’. The dive was on a similar path, to the right hand side of the beach, and there wasn’t much to photograph.

An hour later we met up with the group at the carpark. No kingfish but they did have a John dory, a stargazer and a large octopus.

It could be argued that they didn’t take much but there also wasn’t much to take and the commando raiders vacuumed up what was there. Their stargazer and octopus could have been taken by hand. I mentioned this to the leader and he told me that what he was doing was legal. So that was that; end of conversation!

Spearing on scuba is illegal in some places. Here are some results from a quick Internet exploration via Google: You can’t do it in Queensland (1), New South Wales(2), South Australia(3) and Mexico(4) and there are probably more places to add to the list. This does provide food for thought and I believe that it is in our best interests to question whether or not we are putting our reefs under pressure from what is still a relatively new fishing practice: guns with tanks!

Scuba allows the hunter easy access to creatures that would not normally be taken by line, that are not being monitored or protected and that add considerable variety to the mix of life on the reef. I am hopeful that experienced spearfishermen who hunt on snorkel show discretion and avoid spearing the vulnerable and the defenceless; the speared porcupinefish I saw last summer on the beach at Matheson’s Bay was, I hope, a rare event!

But it’s the new guys that worry me. Is there some way of establishing or perhaps re-establishing diver etiquette?

This would include a no gun-with-tank policy and a deeper respect for the reef inhabitants and other divers that want to have a quality underwater experience. If enough of us behave badly then the law will eventually step in anyway.

What is really interesting is how our behaviour influences fish behaviour. A scientific study was conducted to observe the behaviour of two species of Mediterranean sea bream (a fish similar to our snapper) to divers within a no-take reserve and outside of one(6). The study found that outside a reserve in an area heavily targeted by spearfishers, fish displayed an altered escape response. Instead of swimming into a rocky shelter, as would be the natural escape response, they swam out into open water. The authors also commented that ‘scuba divers well know that fish are not confident at all in places where spear-fishing is intense, which means that fish stay far away from humans (with or without breathing apparatus) to avoid the risk of being speared'(6).

Perhaps the combination of guns with tanks will further dent our reputation with our local reef fish.

It is clear that we can deplete a reef of fish life or frighten the hell out of reef inhabitants every time they hear bubbles. One way to measure our overall influence is through comparison with a no-take reserve. At Goat Island, one routinely sees very large and mature snapper (along with large crayfish, moki and blue cod). Dr Nick Shears, an Auckland University marine biologist, has also told me that there is clear scientific evidence of more diver-positive fish behaviour within the confines of the reserve, whereas fish outside reserves show a diver-negative response. Although this is probably reinforced by some divers providing an illegal feed for snapper in the reserve.

The age of the Goat Island reserve approximately coincides with the age of old snapper: they mature at around three years but they live to 35 years(5). As they mature they move out into deeper water and then return at about 12 years to spend the rest of their life on the reef. So snapper and probably a lot of other reef fish don’t move very far from home and it takes a while, literally a generation in human terms, for them to get really big.

The same species can be observed at Matheson’s Bay, a settlement north of Auckland that is close to Leigh and on the other side of the peninsula to Goat Island. I regularly dive there several times a year but I have never seen a snapper of the size routinely encountered at Goat Island.

To be fair, we can’t attribute this to one single fishing practice such as spearing on scuba. Commercial and recreational line fishing are major contributors and other practices like gill netting can be very damaging. We also don’t know how widespread spearing on scuba is. It might involve a very small number of divers, although I seem to be meeting up with them on land and underwater: a guy with a gun in each hand swam past me last year!

How can we have more diver-positive fish?

No-take reserve protection is a solution. We have blue-water reserve areas such as the Poor Knights, Tawharanui and Cathedral Cove, but Goat island is the only no-take reserve for the diver with beach access near a parking lot. For this reason it is extremely popular. But one blue-water reserve for the scuba diver is not enough. When there is a northerly or easterly wind you can’t easily use Goat Island and the car park is usually pretty full!

If I was asked for another option I’d suggest Matheson’s Bay on the other side of the peninsula. This bay is extremely popular for local divers and it offers interesting underwater scenery. Full marine reserve status for Matheson’s would provide Auckland divers another spot to meet and experience more large diver-positive fish in a location with easy carpark beach access. Importantly – it would be off-limits to the guns-with-tanks commandos!


(1). Queensland Government Primary Industries and Fisheries

rules for spearfishing


(2). New South Wales Primary Industries Fishing and Aquaculture

Spearfishing in NSW: spearfishing


(3). PIRSA (Primary Industries and Regions South Australia)

spearfishing rules:


Mexico spearfishing rules:

(5). PIRSA (Primary Industries and Regions South Australia)


(6). Guidetto P, Vierucci, E, Bussotti, S, Differences in escape response of fish in protected and fished Mediterranean rocky reefs. Journal of the Marine Biological Association of the United Kingdom, vol. 88, no. 3, pp. 625-627, 2008.

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