Where you find snapper in the Hauraki Gulf can vary by the season and according to the water temperature, and this, in turn, can determine the most effective techniques to target them. Sam Mossman sheds some light on factors affecting the seasonal movements of one of our most popular fish and how to target them effectively.
Water temperature is one of the main parameters affecting the movement of snapper around the Hauraki Gulf. Sea surface temperatures vary over the year (and also from year to year) and the amount of change also differs, depending on the area. The following are some ball-park figures for annual temperature variations in different regions of the Hauraki Gulf:
Inshore variation: 12 degrees
Central variation: 7 degrees
Outer variation: 5 degrees
The difference in water temperature occurring in the Hauraki Gulf’s different zones can be explained by basic physics: inshore (shallower) water has a greater percentage of its mass exposed to the surface than does deeper water, so is more quickly affected by the sun or cold winds, warming and chilling more rapidly. In deeper offshore water, the opposite is true, so the deep stuff has a more stable temperature, altering less and staying warmer in winter.
Water temperature changes affect snapper in several ways: the first is in their seasonal movements. In spring, as the water starts to warm, snapper begin moving into shallower waters to build up condition for spawning. As the water starts to warm up, the metabolic rate of snapper increases and they feed ravenously, making spring snapper particularly aggressive on the bite and easier to catch.
The shallower inshore waters offer richer feeding grounds because, as we all know, the marine food chain is mostly based on photosynthesis – powered by the sun – and most marine photosynthesis happens from the surface down to about 30–50m. So, in general, more food can be found in the shallower water.
Some groups of snapper tend to use baitfish schools as a food source – pilchards in spring and the anchovy runs later in summer. These snapper follow the baitfish schools’ movements, as the little fish migrate into the gulf’s shallower areas. The warming weather of spring increases the plankton concentrations there, bringing ‘work-up fishing’ within range of smaller boats.
In the Hauraki Gulf, snapper are serial spawners, spawning several times over the warmer months. This is probably a breeding strategy to ensure at least some of their eggs will strike favourable conditions. They seem to prefer to spawn in large embayments with stable water temperatures, away from reef country (presumably to keep the precious eggs away from the small predatory fish that live there).
Scientists have also found there is a pretty good correlation between water temperature and snapper spawning success. And although some people have picked up the idea that snapper need 18 degrees of water temperature to trigger spawning, this is NOT the case. Snapper will spawn at lower temperatures, but temperature DOES have a big effect on snapper egg survival.
Water with a temperature of 18 degrees or higher ensures a higher percentage of snapper eggs hatch successfully, forming a strong year-class that will be seen in good fishing when these snapper grow big enough to enter the fishery six or seven years later. The inshore water temperature over the spawning season is one of the factors used to ‘guesstimate’ snapper numbers in future years for fisheries management purposes.
After their initial spawning bout in the Hauraki Gulf, snapper tend to feed up again to put on condition for another spawn or two later in the season. Then, in the autumn, they have a further big chow-down so they can go into winter in good shape. This can mean they will again be found around inshore reefs, bays and channels, or around baitfish schools, such as the run of juvenile anchovies that often appear in inshore waters later, during summer. March and April can provide some great inshore fishing.
When water temperatures start to chill, a large percentage of fish begin moving, by degrees, to the gulf’s outer regions, usually in May or June. In deeper water, temperatures (as mentioned earlier) are more stable and don’t drop as far as in the shallow inshore waters. During this transition period, look for migrating fish around medium-depth-foul ground, where they pause to feed for a while on their journey.
Over the last couple of years, ‘work-up’ fishing has continued right through the winter in the outer gulf. Is this a new thing or has it always been going on? Maybe it has just become more obvious due to increasing numbers of bigger boats (including charter boats) fishing out wide in the snapper’s winter habitat, and word getting around faster via social media. Or maybe the water IS warming up a bit and the snapper are staying more active than they used to over the colder months? The jury is still out.
So, how does all this affect your choice of fishing technique? The first part of successful fishing is to find the fish. For example, not all snapper head for the outer gulf to sit out the depths of winter. Some snapper (I’m guessing about 20-25% of them) stay inshore, mostly tucking up in heavy, shallow foul or high-current areas such as channels. The colder water slows their metabolisms, so they do not feed as actively as during the rest of the year, and bite times can be short.
One way these inshore winter fish can be targeted in the shallows is with soft-baits. It pays to target them during low-light periods, early and late, and to look for areas in the shadow of cliffs, which prolongs the fishing.
As you are fishing shallow foul, use lighter jig heads that do not sink too quickly and snag you up. Use natural colours – greens and browns are good – with lots of movement at low retrieve speeds. Grub tails and ‘Crazy Legs’ are good examples, in 4- or 5-inch sizes.
If the fish are not biting lures, or if you prefer baits, try the ‘long game’ by anchoring up-current of a big patch of foul, running a berley trail and stray-lining with lightly weighted or unweighted baits. Be patient, keep your bait size down – about half the size of a matchbox – and pay attention to the lightest bite. At this time of year, even tentative nibbles can be made by good fish.
Targeting fish efficiently, in the right place at the right time, is half the battle, which is why I have been banging on about the seasonal movements of snapper. Having located the fish, consider what is the most efficient method of getting at them, fishing in a way that syncs with how they are feeding.
For example, in shallow water, as mentioned, soft-baits are great because they provide a very natural presentation to the fish and you are not penalised by the length of time the softie takes to sink down to the fish. But in deeper water, if the snapper are on the bottom, a faster sinking lure – such as an inchiku, kabura, or slowpitch jig – may be preferable, because they get down to the strike zone much faster, so spend more time down where the fish are. They can hook up and have the fish in the bin before a soft-plastic even gets down to where the fish are holding – if it gets there at all. Snapper may love the natural presentation and feel of a softbait, but that is of no use if they never get to see it. In general, it pays to use fast-sinking lures in deeper water.
You may also need to consider whether the snapper are on the bottom or in mid-water. Before Xmas, a mate and I were fishing a work-up where kahawai were chasing the baitfish around in midwater and on the surface, with snapper underneath on the bottom. Using a slow-sinking soft-bait, I was constantly getting nailed by big kahawai before I could get down to the snapper, while my mate, using a heavy Bottom Ship lure, was getting down much more efficiently and catching mostly snapper.
On another occasion, when there were no kahawai about, with a slow drift and the snapper being shy to bite, the slow-sinking rubber was more effective on snapper than the metal.
Knowing what has been happening in an area can help, too. One spot I fish often produces great work-up action with lures in early spring, as the snapper move inshore chasing big schools of pilchards. This can provide some great classical work-up fishing, but the last couple of seasons have seen the activity attracting the attention of commercial pilchard netters, who have decimated and dispersed the big pilchard schools.
Consequently, with their primary food source much reduced, the snapper spread out widely over the bottom, grubbing for whatever they can find and making lure fishing very hit and miss. But anchoring and setting a berley pot near the bottom can gather these snapper to your boat, where baits fished on ledger rigs or weighted stray-line rigs can still provide some good catches.
To be consistently successful with snapper, it pays to remain flexible, think about where the fish are and what they are doing at any given time of year, then choose the right techniques to effectively target them.
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