Reef Life Survey - Sydney's changing reefs

Reef Life Survey Webinar Transcript

Terrific.

um so thanks Toni, uh

it's really amazing to have so many

people here

uh today on this webinar which uh you

know who would have thought so many

people were interested in the marine

life of sydney

uh for me of course it's fascinating but

uh at least there's at least 62 other

people at the moment who also think it

might be interesting

so in this presentation which we'll go

for about half an hour.

I'm going to start by talking a little

bit about Reef Life Survey and what we

do when we're underwater

and then look at the sort of information

that we've been able to gather thanks to

the combined efforts of hundreds of

volunteers around the world

and more particularly in sydney and what

it might tell us about how sydney's

marine communities are changing.

We'll talk a little bit about what might

be driving those changes as well but of

course

that's really um based on uh some

speculation and the experiences of

scientists

because really we need to do a lot more

analysis to know for sure but

that's part of the dialogue is what

might be driving these trends.

So if i now share my screen

i hope you can all see this presentation

now

great so as Toni said if anyone has any

questions please type them into the Q and A

as i'm going because that then allows us

to see them

and curate them ready for the Q and A a at the

end.

So Reef Life Survey started about 13

years ago and it was an attempt by

scientists in the University of Tasmania

to engage the diving community to help

them gather

scientific data and it really is one of

the citizen science success stories

around the world because since then it

has expanded to 53

countries uh over three and a half

thousand sites have now been surveyed by

Reef Life Survey

and the tally is upwards of uh close to

five

thousand species have been recorded

somewhere in the world on a survey

and it's not just about recording the

data it's about

helping divers to get

skilled up to the level where they can

collect that information which takes

quite a lot of effort

on the part of the volunteers but also

to inform

management and policy so we can do a

better job

in the future of managing our marine

communities.

So when we go underwater the first thing

we do you can always tell when we're

doing a reef life survey because we're

carrying a lot of gear that you wouldn't

normally carry namely a reel

and a slate uh and often a

a camera as well the first thing we do

is we find a section of reef and

if it's a repeat site we go back to the

same section of reef and we run a 50

metre tape

out over that reef and then we do three

types of data collection we record all

the fish species that we see

in front of us as we swim on both sides

of the tape

not only the species but also their size

and

abundance so it's quite a big job to be

confronted by a school of fish in the

tropics and be able to say well

these are all the species i saw and how

many they were and how big they were

nonetheless with enough training you can

sort of get on top of that challenge

so that's the fish survey called method

one.

We then uh surveyed the bottom below us

this time one metre wide and we look for

the sort of fish that you wouldn't pick

up in that first pass. So the cryptic

fish the little gobies and so on that

hide in the nooks and crevices

and also the invertebrates crabs and

urchins and sea stars and so on

we call that method two. Finally we

run back along the tape and take

photographs of the bottom

and those get analyzed later to draw

conclusions about for example how much

kelp was there on that transect or how

much

coral was there so that whole process

with two divers can take

up to an hour in a particularly diverse

site

and that's one survey of which we've

done

thirteen and a half thousand times so it

gives you an idea of

the volunteer hours and the effort

that's gone into the data that is now Reef Life Surveys database.

So about 13 years as i said that was the

start

10 years ago in 2010 a small group

of very dedicated volunteers set out on

a Lap of Australia's coastline and

recorded

as many sites as they could over that

year

and it's several hundred sites were

surveyed. You can see the dark

dots on this graph for the sites that

were done in that year

and the light dots are the ones the

other sites that have been done in other

years.

But that takes funding and it takes time

and so

in the subsequent years we do as much as

we can but it might be

okay this us surveying Ningaloo or we're

surveying LordHowe island

and Sydney and so it's a subset each

year.

But thanks to the funding by the Ian

Potter foundation this year

we're able to go back and repeat that

big exercise of an Australia-wide

lap of AUS it's going to go into 2021

thanks to coronavirus but that's an

amazing project to be part of

and we've started of course uh we've

actually just finished the Sydney

surveys as part of the Lap of Aus

and we'll do them uh again next year.

So we'll get

actually in case of Sydney two sets of

data as part of this project

and that will support

scientists analysing the oceans but also

government reports like the State of

Environment report.

So with that much data in Australia but

also

around the world we're able to draw

conclusions about some pretty big trends

that you couldn't draw

otherwise. It would be very difficult to

have a scientific project that would go

out and gather all that data

in a funded way to draw conclusions on

say what's happening around the globe.

Whereas with Reef Life Survey we can, and

in 2014 published in 'Nature'

there were some really uh big trends,

conclusions about big trends globally.

I don't know if you can see the top

fifth there but the first two

authors are our other two uh panelists

today

uh Greg Medgar and uh

Rick Stewart-Smith and also Toni is in

there as well on the second line, so

you're in esteemed company. There

were many conclusions from this study

uh but the two big ones in terms of

trends were

fish biomass around the world is down by

about 63 per cent

on historical figures / amounts, so

we've lost a lot of fish out of the sea

or we've taken a lot of fish out of the

sea.

And that's not all fish being the same, so

the bigger species tend to be taken in

preference.

So in the case of sharks the numbers are down over

90 percent

so these two big impacts that humans are

having on

marine populations. Another paper

subsequent to this one looked at

Australia and concluded that over the

last 10 years

fish biomass around the Australian

coastline was down by 30 percent

so they're big trends. Clearly

something that we need to do something

about.

But the focus of today's presentation is

Sydney but i just thought i'd show

those to give you an

idea of what the overall RLS data set

can tell us.

Now let's put the spotlight on Sydney

and this photograph here i particularly

like it because it shows you a couple of

our sites

so these are the amazing places that we go,

you know someone's got to do it, but we

have to go out and survey them.

The front of the photo a little bit

right of centre is

our site called ‘The Gap’ so we survey

that every year. We go around in a boat

uh to the right and behind south head is

another site called inside south head,

very imaginative names.

Then between the

middle

and behind those buildings in the middle

and down the other side are three sites

at Camp cove in the distance, is the

harbour bridge, to the right of that we

have

a number of sites on Middle head ,so

they're the sort of places that we go to

gather our data.

Instead of looking at

that beautiful picturesque angle we look

straight

down here's a map of all the sights

in Sydney and you can see here

we've used colours to show you uh the

protection levels. So the

the majority of sites are those really

pink colours they are

sites that are outside reserves so they

just had the normal activities of

coastal sites.

Going on then we have some partial

marine protected areas or partial

reserves. These are aquatic reserves

that you're allowed to fish in, so

they're only partially protected

and then we have fully protected areas

the green ones.

Here you're not allowed to take any fish

or invertebrates in those.

The reason i'm highlighting this in this

map is we do see some of the trends

in Sydney take place in certain types of

protection levels so we'll come to that

in some future graphs.

But if i look at the statistics for Sydney..

to give you an idea of the effort that

goes into surveying Sydney.

Since 2008 a total of 46 divers, very

highly skilled divers -

(weeks of weeks of training to get

to the point where they can do surveys,

have come to Sydney at various times),

surveyed 64 sites and done a total of

630 surveys, so roughly 10 per site

in the last 10 years collected 27 000

records.

On this fish or this invertebrate was on

this site on this day

at this depth and recorded 265 fish

species

and 192 species on method two so it

gives you a sense for

the depth of information that we can now

draw upon

to look at the trends and what trends

are they?

I’d like to talk first of all about

trends in fish populations

and then in vertebrates and then i'll

talk about

kelp . Which you can see behind me here the

photograph from Sydney with some

beautiful kielp.

So the overall trends in fish

basically on the left you can see the

the mass or the weight of

fish in Sydney's waters per transect

on average per transect um in our

surveys,

over the 10-year period and you can see

from this graph that

it's gone down over that time.

On the left is a log scale so uh it's

not gone down by 10 it's gone down by

more than that.

You might have become familiar with log

scales um thanks to

coronavirus graphs, but basically the

further up the scale you get the

the greater the uh magnification.

So we can see that generally there has

been a downtrend a little bit of

recovery

uh in the last few years and that's

partly due to

some big a big surge in numbers in 2017

which i'll talk about later.

But generally a downward trend in fish

biomass on the right.

You can see that richness so the

diversity of fish species in Sydney

seems to go up and down but generally is

going up and down with no real trend.

If we split that out now by protection

level you can see that

fully protected areas the grey line

are doing much better than areas that

are either unprotected

such as open sites or partial

aquatic reserves. So that's telling us

that those

uh fully protected areas are providing a

sanctuary

for fish species uh and so they're able

to grow bigger

and and build biomass in those sanctuary

areas.

It's not just the size and the

abundance of fish it's also

richness. There's more biodiversity in

those sanctuary areas as you can see in

the right hand graph.

Now that waviness of the graph is a is a

topic that i'll get to

soon, but if we break that up and

look at a few of the species that might

be behind this. So it's hard to sort of

get your head around

overall numbers. Let's look at some

specific fish species -

so we have top left is Luderic and then

we have Trevally

and then we have Bream and then on the

bottom row

the line Blue groper and Red Morewong.

You can see generally they benefit from

sanctuary zones.

Where they overlap like you see in the

line, bottom left

there's not really any benefit conferred

by the sanctuary zone for that species

but generally

they're doing better in sanctuaries.

You've got some that really have that

seasonal

up and down going on but you also see in

the bottom row that

even though we have protected areas

there are declines

in these species. So it led

in terms of the analysis of this data it

sort of led me to dig around a bit and

think well what might be driving those

those declines which are a little bit

concerning.

We started to see a pattern um

if we took all the fish species that we

had enough data for to draw

a plot um and obviously not all fish

are in every year so you can't draw it

for all fish but for the ones we had

enough data

we put all the fish that were going up

that were doing better over time on the

left

and all the fish that are going down

that are in decline in terms of biomass

on the right.

What we see is the fish on the left are

almost

all in and there are more fish than you

can see in this chart but these are some

key ones.

The fish on the left are almost all fish

that do better

in warmer waters so they have a higher

affinity for particularly tropical

waters and warm temperatures.

A lot of the fish on the left are quite

happy in temperatures up around 30

degrees

whereas on the right they tend to have a

maximum temperature

that they're happy to live in around 24

degrees.

So what this is telling us is we're

seeing a bit of a changing of the guard

of declines in cooler water species and

increases in warmer water or tropical

species.

And that's exactly what you would see if

you had warming

waters as we know being driven by

climate change

so this is showing that the effects of

climate change

have been going on in Sydney's waters

now in a measurable way

over the last decade.

But this change doesn't all happen in a

nice even and consistent way it tends to

happen

in waves and we know the East Australian

current runs down the east coast of

Australia brings

warm water down from the tropics in some

years it's stronger than others.

We have various other events like

cyclones

and so when we look at how those changes

happen over time we tend to have

boom years so all of the fish

on this chart

are all tropical species which have

distributions

similar to the one you see in the middle.

See the graph in the middle -

map of Australia all the red flags are

where that fish the striped catfish has

been recorded.

And you can see that Sydney's about as

far south as

it goes - it's much more up in tropical

waters.

So the fish on this um

uh slide all have distributions similar

to that

So they're tropical species but they

don't

come down consistently

every year. There are years where there's

a big surge

in the arrival of tropicals and you can

see on the left

those three species - the wrasse

and then the other two, um

[Music]

the surgeon fish at the bottom and the

common names lost on me, but

in the middle

um had a really big surge in

uh biomass in 2017.

So it was a big year

for

arrival of those tropical species on the

right.

You see that these species also had a

big year in 2017

but also had a big year in 2011.

So there's something going on there with

a surge in arrivals of tropicals which

then

stay and if they are particularly lucky

and don't get eaten

they stay over the winter and maybe

grow bigger and then start to become

established in Sydney.

So there's some of the trends that we've

seen in fish.

Let's now look at invertebrates. So the

invertebrate data when we

measure or survey invertebrates remember

we're going to take photographs of

the bottom in our final pass along the

tape.

So we don't bother to try and measure

things like kelp whatever

in the invertebrate surveys, what

we do is we measure the invertebrates

that move.

So we're counting things like urchins,

crabs,

sea stars, shells so

those invertebrates are shown in these

graphs.

And you can see there's a similar

pattern happening

to fish. So you have a decline in

invertebrate richness um you had a bit

of a rebound in 2017

and it's sort of hung around so they've

maybe survived and

have stayed a little bit but you have

this general decline,

but with a little bit of an improvement

in the last few years.

Now that's all invertebrates.

When we

look at one particular group of

invertebrates, the urchins there's a

different thing going on. So on the right

hand graph

you can see that generally speaking

urchins are doing well

they're increasing over time so whilst

all invertebrates in total aren't increasing

the urchins

are. That's worth exploring a bit

because of the effect that urchins can

have in the system.

Then by the way the left hand, sorry

the right hand plot look at the numbers

on the vertical scale. We normally

quite often we'll record 400 urchins on

one 50 metre transect.

In fact last weekend we surveyed

bluefish point i got 420 urchins

that's pretty normal for a survey that's

a lot of urchins

in a 50 meter tape.

So you might say well that's pretty good

right lots of urchins lots of

invertebrates but

it's not all urchins it tends to be just

one

species that is doing very well which is

the

black or long spine urchins.

On the left you can see it's going up

it's not doing so well.

In sanctuary zones you see the very

bottom graph there with the green

and that may be that because the fish

are able to grow bigger

in sanctuary zones. They can prey on the

urchins and suppress them

which is the normal order of things in a

in a balanced

system. But generally they're still

increasing these urchins.

We call them barren forming urchins because of

all the urchin species in Sydney,

these urchins are such successful as

herbivores as they scrape the rock so well

when they're feeding that they

can strip strip an area bare and create

barren areas.

On the right hand side are a bunch of

urchins some of these create barrens in

other places but not in Sydney.

But you can see that there's once again

maybe a bit of changing of the guard

here because

there's one species doing well at the

expense

of three other species so maybe we're

losing some urchin diversity

even though overall urchin numbers are

going up.

I'll come back to urchins when we

talk about kelp as well because this has

the

impacts for the habitat.

Let's look at

some other

invertebrates now .

With shells there is a

similar story . There are more species

going down than going

up on the right hand side you can see

the ‘ cartridge shell’ the ‘mitre shell’ down

the bottom.

Down with the trends there are a couple

of shells that seem to be doing well.

The Australian triton on top left, not

sure why, that particular one is doing well.

That might be something that's worth

talking about in the Q and A

session. But the one at the bottom with

the question mark the ‘tent shell’

‘Australian tentareform” um there's

there's uh something that may be

happening there because we find this

particular shell in urchin barrens. It

seems to like to live alongside those

black urchins

and it seems to benefit from the fact

the urchins have cleared an area.

So they can then move in as well so that

rebound in the tent shells may be

that they're benefiting from the

increase in urchin barrens.

Some other inverts there are way too

many to show uh and i wish i had more

time but um just a few that i thought

I'd pick out.

On the right hand side of some like

iconic species you know you love to see

these. The bottom right one is an endemic

sea star very colourful.

You get it in all colours orange and

yellow and red and

purple and blue. Sadly in decline, as is

the vermilion biscuit star the one above

it.

The elephant snail at the top but

there are a couple of species that

are trending up um that nudibranch

at the top left, the black margin nudi

branch.

Once again it's a tropical species so

maybe it's quite happy with the changing

conditions in Sydney.

The bottom left is a crab which we

see on a lot of transects quite

commonly found there might be something

else going on there.

Once again we don't know for sure but

one of the things that i would observe

about this crab is we find often

under jetties and around where there's

been um

human development so maybe it's just

quite happy

with the changes that are happening in

the environment and

and isn't being negatively affected by

them.

Let's now take a slide or two,

because algae is basically the forest of

the sea

particularly the large canopy forming

algae

the kelps. So underwater

um we don't have trees but the the

equivalent with

with effectively trunks and a bushy

canopy

are these kelps there used to be

two large canopy forming algae species

in sydney.

The kelp you see here and the other one

was crayweed.

But in the 1970s cray weed pretty much

disappeared

from greater Sydney and only remains up

at

Palm beach and down at Cronulla.

In between those two it just disappeared

in what was believed to be pollution

related. But we've since done a much

better job of the way we

handle our stormwater and sewage and so

the pollution

threat has maybe disappeared but the

cray weed hasn't been coming back of its

own accord,

Perhaps because the urchins have since

moved in and it's too hard

to re-establish itself. So scientists are

involved in trying to restore that . But

the kelp hasn't disappeared

but it is anecdotally getting weaker and

getting smashed by

the bigger storms and thinning out.

If you look at the left hand graph

this comes from Reef Life Survey

data from those photo quadrants. We're

now at the point we don't have a time

series for this yet but we're now at a

point where

there are more barrens than there are

kelp.

Of the coverage in those photographs of

urchin barrens only 20 is kelp

so kelp is being affected by the warming

water which has less nutrients in it. Which is

not good for the kelp.

And also the arrival of fish species

from the tropics that

feed the on the kelp which the kelp is not used

to.

But also the removal of those big

fish from the system

through fishing pressure means the

urchins don't have

any predators and so they're able to

boom

and they can eat the kelp. So a lot of

pressures

going on that are contributing to the

declining

in kelp around the world not just in

Sydney.

I didn't have the time series to

show you yet but

i thought i'd just show you some photos

of what we actually see when we're out

there.

So these four photograph show you

the progression which may be going on

um the top left is a healthy section of

just the very edge of a kelp forest you

can see that sort of tree structure

you can imagine the invertebrates and

the fish that live in amongst that -

Abalone, lobsters, juvenile fish love that

structure

and live in amoungst that structure.

The next shot top right is Bare island

after a big storm came through

so we know with climate change the

frequency

and intensity of storms is increasing

it's smashing the kelp more than maybe

used to be the case

and it leaves behind what you see there.

With that area which has

been

opened up a bit like it's been cleared

of trees with a few odd trees left behind

that allows urchins to now move into that area.

Whereas previously in the top left photo

they couldn't get in because of the

equivalent of tree trunks now they can

move in.

The bottom right is i mentioned we

surveyed bluefish point last weekend.

The bottom right is all is a collection

of the photo quadrants that we took

every single photo quadrat is an urchin

barren.

No kelp, um just bare encrusted rock

with urchins living in amongst it they

live down in the cracks in the daytime

to avoid predators and at night they

come up

scrape all the rock of any algae

recruits that would otherwise turn into

Kelp and then go back down before the sun

rises.

An interesting thing that's starting

to happen

is this may be facilitating the arrival

of corals in Sydney because we have a

colony,

sorry a population of subtropical corals

starting to grow.

Corals which you see

in the bottom left the green

coral colonies that's taken about

a kilometre away from the bluefish

site on bottom right, you can see that

those coral colonies are recruiting to

the urchin barrens.

That's because if the kelp was there

they'd have to compete with the kelp and

it would be more difficult for those

corals

to gain a foothold but the barrens

created by the urchins

allow the coral a place to settle and

grow.

It looks to me like they also then

return the favour because the one thing

that suppresses these urchins is predation and

so they need to hide somewhere during

the day in a crack.

You can see the third urchin there in

the distance

is hiding under the coral so maybe the

urchins allow

those corals to move in and then maybe

the corals provide a place for the

urchins to shelter.

It certainly is happening in other

places it looks like it may be happening

here in Sydney.

So you might say well it's nice to have

corals. Bbut you know,

the iconic species the Weedy sea dragons

the B,lue groper, the Port jackson sharks that

are part of what is famous about Sydney

marine life

are all in that category that need cool

waters and we need kelp.

So just to summarize the trends that

we're seeing happening before our eyes

these aren't forecasts these are things

that are now on the record.

We're seeing uh the effects of climate

change

um over the last 10 years changing

fish populations maybe invertebrate

populations

and certainly the early signs of habitat

changes.

All driven by those climate changes we're

also seeing the effects of fishing

pressure

and when we release that pressure by

putting in the sanctuary zone the fish

populations rebound and we're seeing

habitat loss particularly those kelp

forests.

Now we know what needs to be done the

actions that are needed

to tackle these threats are fairly clear

I don't think it's knowledge that stands

in our way to me , it's just my

personal view but to me what we need is

the support of the community and the

will

to act because a lot of this is out of

sight out of mind.

If it is wasn't for programs

like Reef Life Survey we wouldn't even

have this data

to show what's going on.

Now the good

news for all of you on this

webinar is you can go and explore

for yourselves so a lot of this

information is available online

on the Reef Life Survey website you can

go into the website

look at the frequency or the species

tab uh in the website . You can draw a box

around

Sydney or wherever you want to draw at

Jervis bay or wherever.

Then pull up all the species that are

recorded

inside that box sorted by the most

frequent or

other factors and say hey that looks

like an interesting fish.

In the case of the bottom right you can

see i've drilled in there on the blue

grouper.

I've got a little map showing me where

the blue grouper has been recorded

all the sites description and it's down

the bottom here .

Similar species which is also very helpful

if you're trying to identify

a fish you think oh maybe it's a

Trevally you'd look up the Trevally and

then you look down

and say okay Trevally's often mistaken

for these other species.

We'll use that one a lot so you can look

at this yourself

uh just by going to the Reef Life Survey

site.

So i'd like to conclude with a huge

thanks. This is something that i've been

really privileged to be part of over the

last eight years.

I've learned so much as part of reef

life survey.

So i'd like to thank reef life survey

but i'd also like to thank all the

volunteers.

Those hundreds and hundreds of hours i

mean the volunteers we have in Sydney

give weeks of their time

every year to go out and do these

surveys.

Often they'll give weeks of their time

before they're even certified

to just get trained up . Without those

volunteers

we wouldn't have this information we

wouldn't be able to show these trends

that can inform conservation and

management.

So huge thanks to RLS and the volunteers

and finally to the Ian P otter foundation

who have given us the funding this year

to repeat the lap of AUS.

So i'd like to go back now to Toni

to curate the questions that i hope have

been coming in.

I haven't been able to look but i'm sure

we've got lots of questions.

I hope that Rick and

Graeme and Toni will be helping me to

answer them.

Thanks very much John that was a

terrific presentation and

i'm sure you're getting a very large

virtual applause.

Right now um so yeah as John mentioned

we're gonna go ahead and take

uh some time for your questions.

Just another reminder if you do still have

some questions

for any of the panelists please keep

them coming in the q

a chat box . We will try and get to as

many as possible before

we run out of time um so we do have a

few questions.

So John, maybe this one is actually directed

to you from a fellow Turnbull. Can you

tell us what sharks are found in sydney

waters and whether or not they're endangered?

So I think it's fair to say all sharks

are under threat because

the overall shark numbers are down so

much

so yes sharks in general

are in trouble. In Sydney waters we have

a couple of shark species we find a

lot of and they live on the bottom

they're not harmful unless you

tread on them or something.

So Wobbegongs which have a big wide

mouth

and little barbels uh very cute until

you get

too close. There are two species

of Wobbegong in Sydney - Port jackson sharks

which are named after Sydney harbour -

Port jackson

and Crested horn sharks which look a

bit like them.

So they're amazing, cute

when they're little but we also have um

Grey nurse sharks and Grey nurse sharks are

the more

typical what people think of when they

think of sharks.

They are critically endangered and

there are a couple of

uh small groups that live in Sydney that

you know if you see one of those in

the wild it's an amazing experience.

They are never threatening,

just an amazing predator to see in front

of you. We don't often get them on

transects because they are so rare but

we, I have seen them quite a few times in

Sydney.

So yes a few sharks are none to worry us

we always are happy to see sharks rather

than unhappy.

Yes that's right and it is always a

privilege to see a Grey nurse shark on a

transect.

Rick, i've got one for you.

What do you think is driving the boom

that we're seeing in 2011 and 2017

uh particularly in tropical fish species?

I think um john alluded to it nicely.

With the EAC

patterns. There i think the cycle in the

EAC I think you know

we get particularly warm years that

bring down larvae of tropical species.

I know there's

some other researchers on the line here,

who are experts on this pattern,

and have some great data on this as well.

You know looking at those booms

and the species richness trends that

John showed those those peak years .

If you look at the maximum sea

temperatures for those years they're the

warmest years in that history of our

surveying.

You know with 25 or 26 degrees sort of

maximum temperature.

You know monthly temperatures compared

to 23 - 24 in in the early years.

But you know that if you actually

look at the identity of some of the

other fish too, you know there's some

boom and bust in plankton that no

doubt relates to a little bit of

those data that weren't shown

there specifically. But no doubt relates

to productivity as well you know all

related to upwellings and um localized upweling

and the EAC. .

So there's a lot of things

oceanographically happening there but

that's the the dominant

driver and um yeah it's it's a

well-known

thing.

I think you know the 'Finding Nemo'

phenomenon. It's very clear as John

showed with the data it's incredibly

clear how much the

impact it has when you're doing a survey

or doing a dive in some of these places.

[Music]

Indeed Graham, we've got one for you .

The data shows a decline in

invertebrates in Sydney.

Do you think the invertebrates are also

declining in other areas

and more specifically, Ian asks whether

or not, or why sorry invertebrate richness is so

low inside

marine protected areas.

The short answer is they're

declining quite rapidly

across southern Australia so the whole

temperate Australian biota is you know

really

almost going off a cliff in terms of the

population trends.

Further south you know where you get

onto the south coast it's

well over 30 percent of species are

showing

population declines to those temperate

species

and something also to keep in mind is

that those temperate species

are generally endemic to the region

they're not found anywhere outside

southern Australia.

Something like 72 percent of the

species we're recording in southern

Australia

aren't even found in Zew zealand let

alone elsewhere in the world.

Whereas the Great barrier reef say has

only around eight percent of species

endemic to to Australia that are

occurring on the

on the inner east of the Great barrier

reef.

So what

we're potentially losing here is you

know an incredible

biodiversity that's only restricted to

the area and can't

recolonise from elsewhere.

You know the decline in temperate species is

something that is quite widespread and the

further south

you go the you know the stronger that

that effect becomes.

So you know in in that sense you know

there's a lot of publicity associated

with the Great barrier reef and

and the heating events there. You

know as those species

are warming you know a large number

of them are moving south as well so the

populations

overall are relatively stable if you

look at the whole continent

at the continental level .

Whereas the ones in southern Australia are starting

to fall off the bottom of Tasmania

and that's you know the case with the

hand fishers in particular which is a

endemic family only found in

southeastern Australia now but

you know formerly widespread around the

world.

You know the first species in

that family was listed as extinct a

month ago by the IUCN

red listing process and that's the first

marine species fish species in the world

that has had that listing so um you know

it's a real issue,

and it is kind of starting to get into

the extinction

category. So it really deserves a lot of

attention.

Rick, we've got a question from Thomas,

who asks , "Have you done any comparisons

of the Reef life survey species list for

Sydney, with other speciesists from other

citizen science platforms for example

'inaturalist' to see if there are

species that may not be getting picked up by RLS

surveyors -

possibly driven by differences in

structure versus unstructured surveys. ?

Well the short answer is no, no one's

done that comparison.

I am sure it's there to be made and

would be interesting.

I suspect i mean there definitely will

be differences.

I suspect it's part of it may be to do

with structured versus unstructured

surveys but probably more would be to do with

habitat focus. So Reef Life surveys are

all focusing on reef habitats and so

things that live on the sand or pelagic

animals and things that might show up

once or twice in surveys

it's a bit fortuitously.

Whereas in other

people's observations on 'inaturalist'

you know for example

fishes will be picked up , stuff from

deeper or different habitats.

So there will be definitely differences

there.

I suspect more driven by that

habitat and depth difference.

John we've got a question from David.

"Given that 'Bue grouper' are

protected in New south wales, What do you think drives the

higher abundance in full protected areas, some fishers would claim it's all

about fish feeding.

We'd like to comment on that. " Look

the Blue grouper

the puppy dogs of the sea to a diver as

they follow, they do follow divers in areas where

there's a lot of diver activity. Because

despite uh what we say to people,

you know that people do feed them

just like fishers feed fish with

burley when they go fishing.

So we do impact the environment by the

actions that we

take and and Blue grouper are not immune

to that. But they're not fully protected so they

are protected from spear fishing

outside reserves but they're not

protected from line fishing.

So we may be seeing the effects of um

line fishing outside the reserves. They are also poached, so even

though they're not meant to be speared

perhaps they are. We all know that a

lot of Australians don't follow the

rules all the time

not just one particular type of user but

that's an Australian thing to sometimes break the rules.

So they might be being poached but the

other thing might be they might just be drawn

to the more diverse habitat inside,

not habitat, but more more diverse

communities inside

sanctuary zones. Because you've got

higher diversity

and so it may just be they have an

affinity for

places that have more fish in terms of

protection from predators, fitting into

schools, bigger groups of fish. These are all

suppositions.

I / we haven't done any of these as studies.

It's a really good question

but i don't think it's just about

feeding them.

Yeah yeah i agree."

Graeme, Toni can i just.

Margaret made a comment there. Ithink

it's important to

reinforce that divers are taught not to

feed the fish and it's not

recommended. It's a minority that do

it of course.

Yeah that's a really good point.

Yes we've got another question from

Thomas uh for you Graeme.

[Music]

I believe that ronella or australasia

feeds almost exclusively on obsidians.

So if obsidians are one of the winner

invertebrates

over the last decade, uh that could be

driving like oh sorry sorry, if obsidians are

one of the winners of the invertebrates...

Could that be driving ronella's success?

As well um or perhaps

some of the other assyrian predators are

losers and suddenly finding the obsidians all

to themselves . Do you

have any speculation on this

relationship or other winner loser

relationships like that?

I think that's that's quite likely and

it's a good suggestion.

When i saw John's craft there

you know that was really the first thing

that i started thinking

about in terms of the you know the way

that the urchin barrens are increasing

and

obsidians are quite often associated

with those urchin barrens .

So you know there's a number of

interactions that are going on in the

system. It's never really a straight

you know this does this and that's the

response. There's you know a whole lot of

biological and environmental and habitat

factors that

you know all interact to particular ways.

But i think you know that's a

good idea. I think it is

quite possible that the relationship

with brunello is

is very much tied into the

obsidian prey and

you know that would be the first

step to look at to see how the obsidian

numbers are going and

whether they're doing something similar.

If they're not well it

means we'd have to put that one out and

start thinking of another

another hypothesis to explain it.

But it seemed reasonable to me.

Rick uh we've got a question

from ella who asks is there a way that

we can explore these

trends that we're seeing ourselves

without having to analyze the raw data ?

Or is there something that we can do that s more convenient?

There is a there is actually a um

an indicator reporting tool under

development that will hopefully be

released soon in the coming months on the RLS

linked through the RLS .website.

So things like urchin numbers species,

richness, fish biomass and some of the key indicators that

are applicable

elsewhere as well globally not

just related to Sydney. They'll be explorable on a pretty

fancy tool that we'll look forward to releasing

obviously and we'll be

sharing the news with everyone

when that comes out. So

everyone can keep their

eyes open for that announcement and that will be

fully interactive as well globally won't

it ?

Okay so we have some more

um urchin related questions. So this

could be for

anyone really. We've got a question

uh whether or not urchins are

analogous to Crown of thorns,

for kelp ?

Could pollution be encouraging their

larval stage ?

What can we do to control the

proliferation of

urchins apart from physically removing

them from the sea floor ?

So John you might want to start us off

on that one. We are in such esteemed company i didn't want to

be the first.

Look i think we've always had urchin barrens in this

region and so it's not necessarily that they're

new. It's just that they're benefiting

from the changes that are going on.

They like the warmer waters , they're

quite happy, they're very

good at breeding and they're very good

at scraping the rock

clean . So i think there are a few things

that make them

successful . I don't know if i'd make them

analogous to any particular

other species but certainly crown of

thorns does have a similar impact in coral

systems. Crown of thorns benefits from

extra nutrients

in the system which the larvae

feed on and therefore live larval

survival is higher. I believe

with crown of thorns i don't know if

that's the case with

'central stephanus'.

I do know that when we

were down in Tasmania doing some surveys

there was a community meeting in Bicheno

about this issue. They were talking

about can we just remove them from

the system ? Can we

you know harvest them? Because the roe

apparently well actually i tried some -

the roe tastes like oysters to me . But then i

don't really like oyster so maybe but the issue there is they

live deeper than we could go to collect them.

So you know practically speaking you can

only collect them down to say 30 metres

as a diver. Whereas they live deeper than that and

so they can easily come

up and re refill an area that you might

have stripped through harvesting.

I can add a bit to that. You know there is a big difference

between crown of thorns and

the black urchin in the sense that

the crown of thorns are boom and bust

they have their busts as well as booms.

So you know they require an ongoing source

of coral or whatever to feed on . Whereas

urchins are very unusual in the animal

world in terms of starvation and

you know being able to persist on very

minimal dietary requirements. So once

they're in an area

you know basically you've got

12, 15, 20 years for their life history

before those animals will die.

And that has, you know big

implications in terms of recovery of the

area. Coralyou know goes up and down following the

crown of thorns outbreaks. Whereas with

the urchins that

doesn't happen . You know they're

not a complete disaster as you say

they're you know they're part of the New

south wales system

and you know a number of species are

dependent on the habitat that

that they produce. There's certainly much

more of an issue in Tasmania which

you know isn't used to having the

urchins there and they only first arrived

35 years ago. They are

something of interest is that they are

piloting a scheme here where they're

subsidising the fishery

for them and paying i think one dollar

bounty for the processors who are processing

them and exporting them . So it's not

cost effective to to harvest urchins

to harvest that particular species of

urchins. The other urchins that you showed

before the

the ' iliaceteras ' are more commercially

viable but you know it's right on the margins in

terms of commercial acceptance and so

by putting a small bounty on them they

are actually developing a fishery for

them to

control the numbers in Tasmania to some

degree anyway.

The important thing there is that

there's a very strong negative

relationship between urchin barrens and

abalone numbers and rock lobster numbers. So

you know it's very much a commercial

issue in Tasmania to try and stop the

sea urchins to keep those fisheries going well.

Great thanks for that.So

just one more quick one. Just about the

urchins while we're on that topic

before we lead into another question

that Rick's going to tackle.

David asks he says that urchin barrens

seemed to have been prevalent in Sydney

for many decades

and species richness and biomass in

barrens versus kelp

is higher for both local and tropical

species in shallow waters.

Some kelps proliferate in shallow

water so is it dynamic or is it real

kelp replacement by barrens going on in

Sydney?

Well from my viewpoint i don't know if

we know the answer to that.

We can only show the trends and to

really answer a question like that we

need to do

more research. So i don't know i can add to that.

I don't

know if Graeme,

you or Rick you have any further on that

one.

I can't really add anything to that

without knowing what the

history, and I don't know anyone knows

the history of the dynamics between the

urchin barrens and kelp and Sydney.

But you know for the present anyway both

are important . The real issue becomes if

you know one dominates the environment

you know at the expense of the other one.

That would preclude a big chunk of

biodiversity out of

the system but you know having the two

components there

you know is part of the natural

process as far as i understand.

I don't have anything to add there

i think it's a long discussion and it's a

complex question requires some complex

answers and i think Dave

probably has some some hypotheses there

which I am pretty sure is going to be as well

informed as anyone's on that .

So then leading on to that Rick while

we've got you Mark says that it must be frustrating to

document changes

and see little political action with

respect to climate change.

Can you tell us a bit about how RLS

presents its findings to decision makers

and how how does the new south wales

goverernment take any notice?

There really good questions about connecting the data to

to the government and to decisions

and there's there's two elements there.

You know we

we certainly don't just um collect the

data and put it up there and expect it

people to take notice . There's actually

some active

engagement with RLS - part of it is the

through the advisory committee so there

are state government representatives

from all of the southern states and

western australia and northern territory

on the RLS advisory committee

and so the New south wales DPI

representatives

are there to guide the not only the

data collection but also

to basically to absorb the

information that comes out of there and

connect it to the right people in the

government.

There's also the engagement of

Reef life survey

data in the nest marine biodiversity hub

and so that is working with the

Australian government.

So New south wales DPI is

actively involved in that that they're

also a partner.

So the data get fed up through projects

including the 'State of the environment'

report through the government in

those multiple

ways. The tsecond part of

that

question is even if when the

government

have the information at hand and

want to make real action their

politics comes into it as well . So

public knowledge is arguably equally as

important well it's actually more

important at the end of the day

um than the government knowledge and so

it's good that the government

both the New south wales DPI and

Australian government do know

the trends but they also need the

Australian public to know the trends to

have the right

to put the right pressure on them and

hold the decisions accountable.

So yes we do

our best to to try and keep the

government uh in the loop and they do

actively engage with RLS

-translation to real decisions you

know is affected by more than just that

though.

All righty and we're running out of time

so just quickly on that then will this new tool - do you think

that will be

helpful for communicating with other

managers as well, will this be more than public problem?

That's a question for me ,

sure , so is this Bill's question ?

Okay so Bill's question.

The new tool is designed so that

everyone ,basically, it's so there

anyone that's interested can

can interact with the data and the

trends. Importantly it offers an opportunity to

download the indicator values , the raw

data - you know to undertake your own

analysis in-house . So

it will be of interest to just

members of the public who can just

explore the trends, but it also is useful for for

scientists and scientists within the

government to download

the values. So we will

hopefully have some instructional videos

and some

sessions too for people to learn how to

to use all of the features when that

comes out.

We would hope that it's also a tool

that members of the public can use to

help isolate some trends to to show to their

local governments as well.

So hopefully it will be very useful for

that for that purpose Bill.

Great thanks Rick and thanks Graeme and

John. We're just about out of time

so we'd better wrap up. So apologies if

we didn't get to

all your questions but if anyone does

have any further questions for any of us

feel free to send us an email at

inquiries@eeflifesurvey.com

As Bill mentioned as well it

sounds like he would be quite interested

in a bit of a data. There will be a

webinar as well about how to use the new

tool that we're developing so

if you enjoyed this webinar then keep

your eyes out for potentially another

one coming to you very soon. So thanks

very much for everyone for your time

today and for taking time out to join us.

Thanks very much John for your great

presentation . Did you want to finish off

with anything before we leave ?

I thanked everyone before but i'll

take the final opportunity to thank all

the participants .It's great to have

60 odd people

in the webinar and giving up an hour of

their time so

thanks all for coming along and hope to

see you out either in the water or maybe

online.

Great alrighty we'll wrap it up there so

thanks everyone and hopefully talk to

you all soon.

Cheers, thanks Toni for organising

with John.

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