10/09/2026
Since just before the sardine die-offs began, there has been a noticeable increase in the frequency of unseasonal common dolphin encounters around the Bay.
Yesterday, we once again spotted a super pod of offshore common dolphins, moving at an unusually slow pace. I couldn't help wondering if they were simply overwhelmed and stuffed with weakened sardines.
All indications are pointing towards a major sardine mortality event, with pilchard herpesvirus (PHV) detected in affected fish. And importantly, the bulk of the dead fish may not be washing up on our beaches.
PHV has previously been associated with major sardine die-offs in Australia. Environmental stressors such as temperature, and water quality also appear to be contributing factors.
And this is where things get interesting.
Sardines aren't just tins of protein.
They are a critical link to many parts of the ocean, a staple within the marine food web.
Sardine eggs and larvae feed plankton and pelagic fish. As sardines grow from fry into juveniles and adults, the list of predators expands dramatically to squid, hake, mackerel, dolphins, seabirds, tuna, sharks, whales such as Bryde's whales, and many other predators.
Remove a huge amount of sardine biomass from an ecosystem and the consequences don't stop with the sardines. They ripple upwards through the food web.
So what happens next?
Do we see increased mortality among seabirds, penguins, whales, sharks, dolphins and line fish as food becomes harder to find?
How many of the various sardine populations have actually been affected?
How much reproductive potential has been lost?
And perhaps most importantly.
Can the ecosystem absorb this shock and recover?
We also need to be careful not to blame any single factor at this stage. PHV appears to be an important part of the current sardine mortality investigation, but environmental conditions and water quality may also be contributing.
Sewage and other pollution certainly don't help.
Neither does a changing climate. Human emissions are measurably increasing ocean temperatures, while melting ice can also alter ocean circulation and temperatures. Extreme weather patterns are becoming increasingly heavy in many parts of the world.
The ocean is an enormous heat sink, and its systems are constantly working towards equilibrium. Because many oceanic changes happen slowly, we tend to overlook just how important those systems are.
And then we suddenly discover how interconnected everything really is.
Only the ignorant believe the ocean is something we can master.
The paradox is that the ocean is something we have to survive and, at the same time, the very reason we have survived.
Things don't necessarily have to change very much in the ocean for the humanity to face enormous consequences.
I don't want to sound overly onimous but from my perspective, I honestly can't see many reasons to be optimistic about our current trajectory.
This path leads somewhere unpleasant, to put it mildly.
