For Kiwi anglers, small fish like mackerel and pilchards are a means to an end. Just look at the collective term we humans have coined for these species – ‘baitfish’. We see them as bait for larger, more endearing fish like snapper and kingfish.

The importance of baitfish

Back in my halcyon days as a charter skipper, we would regularly devote a decent hunk of the allocated fishing time to catching livebait. Jack mackerel were the prime targets. Commonly forming schools in areas around the Hauraki Gulf, we had specific areas where we tended to find them in certain seasons, but we would also keep our eyes peeled for the telltale baitballs appearing on the fishfinder as we cruised between possies. 

When the screen lit up, I would spin the boat around or slam the engine in reverse.

“Go, go, go!” would be the call from the helm as the clients dropped their sabiki rigs down through the mid-water schools. On a good day, all six rods would start jiggling in unison as the mackerel intercepted the descending bait flies. On other days, it became an exercise in frustration chasing around the enigmatic bait schools.

Although these ‘livies’ were treated gently when caught – unhooked with a butter knife and dropped straight into the bait tank – they would inevitably later end up unceremoniously tethered to a circle hook and sent down to awaiting kingfish. A means to an end. 

I digress. The point I’m circling back around to is that baitfish, although they are generally an afterthought for recreational fishers (exceptions include aji anglers – see page 86 of this issue for Grant Bittle’s exposé on sportfishing for jack mackerel), are a crucial part of the whole angling equation. Quite aside from their angling application as live or dead bait, they are a key food source for many of the fish we like to catch.  

An example that perhaps most unequivocally shows the value of baitfish in the food chain is a workup. In typical academic fashion, scientists have come up with a complicated term for these events: multi-species foraging associations. In contrast, a recreational angler might describe workups simply as “bait being smashed.”

Kiwi marine biologist Rochelle Constantine, best known for her research and conservation efforts regarding the Hauraki Gulf’s Bryde’s whale population, has long appreciated the role of baitfish in the ecosystem. 

Baitfish like jack mackerel are a crucial part of the whole angling equation. Quite aside from their angling application as live or dead bait, they are a key food source for many of the fish we like to catch. Photo: Ben Starns.

“Bigger fish eat them, sharks eat them, dolphins eat them, gannets eat them, whales eat them… they’re a high-value nutrition item as well.”

The stereotypical workup stems from a school of common dolphins locating and herding a school of baitfish into a writhing ball. Watching gannets will then rise into the air and begin circling above, before starting to rain down with perfectly calibrated precision. It’s not long before other predators and scavengers enter the fray – shearwaters, petrols, and gulls from above, and kingfish, kahawai, and snapper from below. And eventually, the ultimate predator/scavenger sniffs out the action – humans, armed with either a fishing rod or a purse seine net. 

There are also those workups that are less likely to make the cut for an Attenborough-narrated cinematic production. Action like a handful of terns flitting around plucking anchovies from the surface while kahawai erratically splash about. Whatever the scale or grandeur, there’s no doubt recreational anglers enjoy the spectacle, yet the primary reason we get excited is the fact that workups are a signpost pointing the way to impending fishing action. A means to an end.

Baitfish under attack have always led the way for anglers. Tararukuruku, a Māori word used to describe a workup, refers to the flicking of a seabird’s tail just before it dives. Early Pākehā simply targeted those waters alive with small fish being chased, and the famed American writer/angler Zane Grey, who pioneered gamefishing in the Bay of Islands early in the 20th century, wrote floridly about the dance between predator and prey in his Tales of the Angler’s El Dorado.

“The white gulls, like showers of feathers, were now rosy in the sunset glow. They ascended to fly over the frothy patch of water [which] roared like a running brook, and screaming, they alighted amidst the school… evidently feeding on the tiny minnows the kahawai were chasing.”

“The air was full of moving fluttering specks of white. Crash! Another great swordfish had smashed at the school.

“The battle went on. It was life and death, something vital, beautiful, inevitable and unquenchable, and at the same time sinister and tragic.”

Baitfish under attack have always led the way for anglers.

I asked Denham Cook, a scientist who works with the pelagic fishery based out of Tauranga and lectures at Waikato University, which important recreational species rely on baitfish in our waters.

“There’s good evidence that snapper, kahawai, kingfish, and marlin all eat at least some of these species. However, given the range of sizes across the various ‘baitfish’ or pelagics, and the marked size differences between juvenile and adults of each of these species, not all are easily preyed upon by each of these predators.

“As New Zealand possesses a relatively complex marine food web, marine predators are highly opportunistic and are able to eat a phenomenal range of food. Take snapper; they seem to be able to eat almost anything from worms, crabs, and shellfish, to small fishes. Size does matter and for example, only big snapper are big enough to eat jack mackerel. Past research has shown that jack mackerel make up less than 1% of the diet of large snapper, although we don’t have any new data to ensure this is still currently the case. Also, at different times of the year these pelagics aren’t even around, because they move with the seasons and conditions. This is why less mobile predators need to be opportunistic.”

Cook thinks New Zealand is fortunate to have a variety of baitfish species.

“What we are calling baitfish here might include a big range of species in New Zealand.  They are generally pelagic fishes that spend a large portion of their time feeding and swimming within the water column (e.g. not on the seafloor). These range from ‘small’ forage species like pilchards, anchovies and sprat that feed on the plankton and small zooplankton that form the base of the marine foodweb, to ‘medium’ size predators like jack mackerel, blue mackerel, trevally and skipjack tuna that feed on larger zooplankton (krill) that form the middle portions of the food chain.   

“In some places in the world, there are really only one or two baitfish species and they occur in hugely variable volumes. They are the only channel for transferring energy from plankton to larger fish, up the food chain (e.g., to apex predators such as sharks and predatory marine mammals).

“In New Zealand we have a more fortunate situation because we don’t just have a couple of [baitfish] species, there are more than ten of them. That means no one single species is the be-all-and-end-all. It means we have a more complex and more resilient food web.”

Has the baitfish baseline slid?

Most well-weathered recreational fishers will agree that the supply of baitfish is waning. Hand in hand, sights such as coastal waters foaming with schools of kahawai and trevally, each spanning an acre or more across, have also evaporated.   

There’s also empirical weight backing up the anecdotal stuff – the Hauraki Gulf Forum’s 2020 State of our Gulf report notes there has been a 57% reduction in the population of jack mackerel and a 32% reduction in other small pelagic species in the Hauraki Gulf Marine Park, while tagging studies have shown that although the diet of our Bryde’s whales previously consisted mainly of fish like pilchards and anchovies, the whales now primarily eat zooplankton. There’s also the recently released NIWA report showing that malnourishment was the likely cause of the mushy-flesh snapper syndrome. 

Talk with LegaSea Programme Lead, Sam Woolford (or anyone from the same non-profit organisation that’s dedicated to restoring marine abundance) about baitfish and you’re guaranteed to raise his hackles.

“There is an obvious loss of productivity between Cape Reinga and the East Cape on the North Island. 

“A lack of baitfish indicates a serious issue within our marine ecosystems, suggesting trouble at the bottom of the food chain. Decades of mass harvesting of blue and jack mackerel within the Gulf and the Bay of Plenty likely haven’t helped the situation.

“We are worried that overharvesting of keystone species such as baitfish is impacting the productivity of other species higher up the food chain such as seabirds and predatory fish.”


Tagging studies have shown that although the diet of our Bryde’s whales previously consisted mainly of fish like pilchards and anchovies, the whales now primarily eat zooplankton. Photo: Guy Macindoe.

But what does the Ministry for Primary Industries (MPI), our fisheries regulator, have to say on the matter? 

Emma Taylor, Director Fisheries Management, Fisheries New Zealand, acknowledges that “for some baitfish stocks there is a relatively low level of data available to inform management decision making. Typically, this is the case for fisheries where use, and therefore information gathering opportunity, is lower.”

This is probably a fair response for those anchovy, garfish, yellow-eyed mullet, and sprat stocks which typically have annual commercial catches under 10 tonnes.

The worrying fact, however, is that some of the jack mackerel, blue mackerel, and pilchard stocks have very significant total allowable commercial catches (TACCs) and/or annual harvests, and despite this, a quick perusal of the most recent Fisheries Assessment Plenary (MPI’s bible on NZ’s fish stocks) reveals a revolving door of phrases like:

•    "It is not known whether catches at the level of the current TACCs or recent catch levels are sustainable in the long-term." – Jack Mackerel 1 (northeastern) stock, TACC of 10,000 tonnes; and Jack Mackerel 3 (southeastern) stock, TACC of 8,780 tonnes.

•    “There have been no stock assessments of New Zealand pilchard.” – Pilchard 1 (northeastern) stock, TACC of 2,000 tonnes.

•    “No estimates of biomass are available for any blue mackerel stocks.” – Blue Mackerel 1 (northeastern) stock, TACC of 7,630 tonnes; and Blue Mackerel 7 (western stock), TACC of 3,350 tonnes.

Nevertheless, Cook says that the situation isn’t as dire as it seems.

“There has been a lot of research done, but again, because these pelagic species move around a lot and there are a lot of them, our findings aren’t as comprehensive as the monitoring for other species. The type of research required and fishery monitoring requirements, also vary from species to species. We are also in a situation here in New Zealand where many of these pelagic fisheries are very small or aren’t even fished at all. There is almost no means to collect information on fish which have no, or a small, fishery. And even our larger pelagic fisheries are very small on an international scale. This means there is not as much information for some of these pelagics as there is for other species such as snapper for example. However, we do have some good sources of information.

“For example, inshore trawl surveys provide some information on the abundance of juvenile jack mackerel in the Hauraki Gulf and Bay of Plenty, fisheries monitor the abundance of jack mackerel in the west coast fishery, and aging studies ensure that fishing pressure isn’t too heavy on any given species.”

Taylor reiterates Cook’s point that there isn’t actually a dearth of research on our baitfish species.

“For blue mackerel in EMA7 (west coast), an assessment was also completed in 2022. It indicated that there appeared to have been a decline between around 2010 and 2016 but that biomass increased after that.

“Jack mackerel off the east coast of the North Island (JMA 1) and blue mackerel off the north-east coast of the North Island (EMA 1) are group 2 stocks with varying levels of utilisation between sectors and regions. The management settings provide for moderate levels of use, informed by partial quantitative stock assessments to monitor their stock status, which are mostly based on trends in relative abundance.

“An assessment for jack mackerel in JMA7 (West coast of New Zealand) was completed in 2022. This indicated the abundance of the two main jack mackerel species was well above the reference points. Based on the assessment, JMA7 was included in the October 2024 sustainability round.”

It’s worth noting that the “reference points” mentioned by Taylor are mere fractions of the unfished biomass, but that’s a story for another day…

Although anglers take small fish from the ecosystem for bait, livebait, or kai, and create demand for their commercial harvest by purchasing frozen bait, the statistics show the impact of recreational fishers is a proverbial drop in the ocean. Photo: Brett Habener.

Environmental stressors

Although it appears that the baitfish baseline is sliding, what’s the cause? 

Unsurprisingly, the answer is probably multi-factorial. Like many short-lived marine species, baitfish numbers are prone to fluctuation. Studies on pilchard stocks elsewhere reveal considerable natural fluctuations in biomass size, both short-term (individual year-classes) and long-term. Several hypotheses have been advanced to explain these; most involve changes in climatic and oceanographic conditions. Climate change is likely a stressor. Warmer waters tend to push plankton further offshore, drawing the foodchain – including baitfish and their predators – away from the coast. The recent NIWA investigation into the causes of the mushy-flesh snapper found that the Hauraki Gulf has experienced a significant decline in phytoplankton and zooplankton productivity – the crucial tiny food sources for baitfish.

Cook emphasises that environmental conditions are the primary determinant of baitfish abundance. 

“These species are all very active and mobile – they continually migrate to where conditions are best. Their habitats can range from river mouths, harbours, reefs, coastal waters, pelagic surface waters, and deep water (100-200 m) You might not see them on your area of the coast but they can still be abundant in other places. Simply said, they go to areas where the environmental conditions are most suitable.”

Some baitfish are susceptible to viral disease: mass mortalities of pilchards occurred in New Zealand in 1995, and Australia in 1995 and late 1998. It is believed that imported frozen pilchards introduced a pathogen new to both countries, sweeping through populations and leaving millions of dead pilchards floating across areas like the Hauraki Gulf.

Although Woolford agrees that environmental factors are affecting baitfish abundance, he suggests it’s only part of the equation.

“Our oceans are under pressure from multiple environmental stressors such as increasing water temperatures and land-based runoff; the last thing they need is for commercial fishers to be taking excessive amounts of baitfish out of the water, messing up the food chain.”

Are we harvesting too much?

As recreational anglers, we need to acknowledge our own impact first. We take small fish from the ecosystem for bait, livebait, or kai. We also create demand for their commercial harvest by purchasing the ubiquitous 1kg bag of frozen pillies at the local gas station or Four Square. Many of these pilchards are purse seined from coastal waters around the North Island.

But the impact of recreational anglers is a proverbial drop in the ocean. All you need to do is look at the statistics. 

Baitfish are taken across a range of different commercial fishing methods, both as a bycatch as well as targeted fishing. Target fisheries for pilchards, jack mackerel, and blue mackerel currently operate in the northeastern area of New Zealand, largely taken through purse seining. There is also a hefty jack mackerel trawl fishery on the west coast of the North Island.

Blue and jack mackerel are some of the top species commercially harvested on the northeast coast, with more than 10 million kilos landed in 2022/23. And what happens to this huge volume of fish? Seafood New Zealand’s 2023 export stats show that blue and jack mackerel are exported for as little as $1.60 per kilo. As demand for aquaculture increases, so too will demand for low-value fishmeal – an obvious market for low-value, bulk-harvested baitfish. 

For jack mackerel along the northeastern coastline there is currently a 10,000-tonne allowance for commercial catch but commercial fishers are only catching 33% of this. The identical trend is apparent for the pilchard stock in the same region, too. Yet, move over to the west coast, and the mammoth 32,538-tonne jack mackerel TACC for that area has essentially been caught (or sometimes exceeded) for the last 20 years.

So why aren’t they catching their limits out east? Woolford proposes it might be because the fish just aren’t there.

Whatever the reason, one thing is abundantly clear: there is little to no information on the status of most baitfish stocks and no certainty as to whether recent catch levels or the TACC for these are sustainable in the long term. If this uncertainty exists, logic worryingly suggests that the catch limits (primarily set around 30 years ago) are simply early guesstimates, extrapolated from minimal observations. As such, it’s hard to buy into Cook’s suggestion that “the catch allowances were set conservatively initially, partly reflecting the fact that the stock moves around and is harder to monitor.”

A better way?

The approach of Ecosystem Based Fisheries Management (EBFM) is to holistically manage fisheries by recognising the whole marine ecosystem, instead of being single species focused. In this way, food sources for larger predatory fish are acknowledged and protected. 

“Ecosystems-based approaches to fisheries management are growing around the world. In New Zealand, we’re working to better account for interactions within the food web and the broader marine environment when making decisions,” says Taylor – although she does include a caveat:

“The massively complex nature of ecosystems means EBFM will always be a pathway, rather than a destination.”

Blue and jack mackerel are some of the top species commercially harvested on the northeast coast, with more than 10 million kilos landed in 2022/23. Seafood New Zealand’s 2023 export stats show that they are exported for as little as $1.60 per kilo. Photo: Tony Orton.

Cook notes that EBFM also encapsulates the weighing up of wider societal and environmental considerations. 

“Nutrient-rich and oily fish like mackerel and anchovies are always showing up near the top of healthy eating guides, and their capture has one of the smallest environmental footprints of any food production system.”

So, what initiatives are being progressed on the pathway to EBFM? 

The Hauraki Gulf Fisheries Plan, developed by the Ministry for Primary Industries off the back of the ongoing Revitalising the Gulf saga, expressly promotes the following management action:

Review the management settings of important forage species in Fisheries Management Area 1 as needed to ensure impacts of removals don’t adversely affect the marine food chain in the Hauraki Gulf.

Fisheries New Zealand is partnering with the Department of Conservation and NIWA on a research project to develop an EBFM framework for the Hauraki Gulf Marine Park, including indicators that accurately reflect the area’s health and ecosystem.

The Ministry for Primary Industries’ Sustainable Food and Fibres Futures has also invested in ‘Pelagic’s 2030’, a project being undertaken by Pelco NZ Limited. The project is set to develop fisheries management tools and data capture technologies to determine the sustainability of a small pelagic fishery in the eastern North Island where the Purse Seine fishing method is used.

The problem is the cogs are moving slowly and so far, there’s little in the way of actual action (aside from a proposal to increase the catch allowance for the western jack mackerel trawl fishery in Fisheries New Zealand’s October 2024 consultation round).

The priority in recent legislative proposals seems to be on creating localised no-take areas, rather than protecting those key species that drive the productivity and resilience of the entire ecosystem. The sad irony of this approach is that there’s not much point in protecting predatory animals in selected areas if they have nothing to eat. As Constantine points out, “All of those animals are working so hard to find their prey and to get enough food… physiologically, a lot of these animals are right on the edge of living and dying a lot of the time.”

“International evidence identifies that if you attempt to manage these sorts of fish on smaller, more localised scales, you will likely fail to achieve your goals. There are some environmental factors we can’t control or influence,” adds Cook.

“If you look at the Department of Conservation’s spatial management in the Hauraki Gulf and the area closures, unfortunately they don’t do anything for migratory species like the ones we’re talking about here. They move! So you can’t restrain them and attempt to protect them by closing certain areas. The best way to manage them is what we do now, with catch limits.”

The priority in recent legislative proposals seems to be on creating localised no-take areas, rather than protecting those key species that drive the productivity and resilience of the entire ecosystem. Photo: Ben Brown.

Woolford wants to see the EBFM concept fully embraced immediately, regardless of whether overfishing or environmental factors are causing the problem.

“If climate is the main reason for decreased food production in the Gulf, then it is the perfect reason for the fisheries Minister to take a precautionary approach and lower commercial catch limits for baitfish stocks on the North Island’s east coast. We need to ease the pressure on an ecosystem already under stress.”

Cook agrees that the EBFM approach is worthy, but the focus needs to be on improving knowledge.

“It is my belief that we would be best served focusing on fundamental research that described the basic functions of our marine environment and its species, and how these two things interact. We need meaningful information and research, not speculation, in order to best manage this broad and important range of species.”

Whatever the mechanism, the time seems right to look at the sustainability of our baitfish populations as an end in itself.

- By NZ Fishing News