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A couple of quick detours before we get back to the coral reefs...
This is what the Galápagos Islands on the opposite side of the mighty Pacific Ocean looks like.
There are big volcanic rocks covered in barnacles. Itʼs very fishy.
We mostly film sharks and turtles and other big stuff here, but the bottom is really interesting too,
and thatʼs where most of the biodiversity is
As fishy as a site may be, I always wonder how different it would have looked 50 or 100 years ago.
The 1982 El Niño warming event pretty much wiped out coral in the Galápagos.
There might have been a coral garden on these rocks before that time.
Mangroves are fascinating places that donʼt get much attention or protection,
mostly because they are hot and muddy and infested with mosquitos and the occasional crocodile.
This is in the Solomon Islands where the mozzies carry malaria, and there has never been a *reported* crocodile attack on a diver—
maybe they just donʼt get reported, I don't know—
but the water is unusually clear so it's well worth exploring.
The fish hiding under the mangrove roots are called Archerfish, they prey on air-borne insects by spitting water up at them.
I've often done night dives at this particular spot and I must admit
it's a bit scary when you pop up at the end of the dive... you get a bit uncomfortable floating around on the surface,
in croc country, on your own, in the dark.
Seagrass is another critically important habitat as far as coral reefs and general ocean health is concerned
Seagrass acts as a filter: it traps sediment, binds heavy metals and nutrients,
and also provides a home and food for juvenile fish and other reef critters like shrimps and snails.
In fact, the majority of commercial fish species rely on seagrass meadows for their early development.
Here we have the Longfin juvenile batfish that have nearly outgrown their seagrass nursery,
and they'll move to a nearby coral reef pretty soon.
Itʼs very common in the fish world to change shape and colour with age.
These batfish juveniles are tall, dark and slender, which is great camouflage in the seagrass.
But the adults are silver and almost perfectly round,
which probably makes them better swimmers and too much of a mouthful for open water predators.
Take a slower, closer look around the seagrass and you'll often find some weird critters doing their best to stay camouflaged.
These little fellas are called shrimpfish, or razorfish.
They spend their whole lives around the seagrass where they suck up tiny animals living in the sand and on the seagrass.
The photobomber is Clarkʼs anemonefish whose home anemone is out of shot to the right,
but If you ignore her and watch the grass closely youʼll also see tiny seagrass gobies—
little white blurry flashes as they quickly leave and return to the grass as they attack then retreat.
Around the world, seagrass meadows are being destroyed by runoff, coastal development, boats and shipping—
and nowhere more so than in my own backyard, inside the Great Barrier Reef lagoon, no less.
Unconscionable port development in Gladstone, for example, is destroying marine habitat and fishermenʼs livelihoods,
and the effects from that one port will be measurable on the Great Barrier Reef forever.
This is part of enormous seagrass meadow in Moreton Bay, just down the road from where I live in Queensland, Australia.
These horned sea stars are common as dirt in most seagrass meadows,
and along with sea cucumbers, they keep the sand clean by eating detritus—fish poo and other organic matter that settles.
This is an important part of the nutrient cycle because if thereʼs too much nutrient in the system,
algal growth goes nuts and smothers the seagrass by blocking its access to light.