on a clock thank you all for being here
we're gonna go ahead and start the
stream now you can see on the side
there's the option for you to type
questions and look into what other
people are talking about but we're going
to start off with a little introduction
by me and some questions that folks
called in ahead of time so first things
first my name is Dr. Rob Nowicki I am a
marine biologist with Mote Marine
Laboratory in Summerland Key Florida so
I live down in the Florida Keys and
spend my day going out and other
collecting data about the marine
environment or sharing those results
with other scientists and with the
public like you guys here I got my PhD
in Florida at Florida International
University in 2016 and I've been down
here in South Florida since then but I
started out actually far away from the
ocean in North Carolina a little place
called Winston-Salem never really spent
much time near the ocean as a kid but
just happen to have some great
experiences along the way that led me in
this career path but I want to start off
by talking a little bit about sharks and
seagrass some of the things that I've got
a background in and you guys have a lot
of good questions I'm gonna go ahead and
get started on those if you see that I'm
not answering a question that you have
type it in and we'll get to it so let's
pull this up first let's see here first
things first
can you all hear me anybody put in a
response that you can hear me all right
okay awesome
thank you all very much so people are really
interested about sharks people obviously
have been for quite a while otherwise we
wouldn't have Shark Week going every
year right but there's a lot of
misinformation out there and that's a
shame because these animals are
incredibly interesting they've been
around for a really long time and they
have a lot of interesting biology and a
lot of relevance to how we live with our
marine environment so we're going to go
out and start with some simple questions
then get to more some more complex stuff
as we go so in regard to sharks got a
lot of great questions about how we work
with them and basic things about their
biology so Izzie cats wanted to know
when we handle sharks are they asleep
like how do we work with them how do we
get them calm some people were asking
whether we tranquilize sharks when we
work with them or whether we're just
using the tools that Nature gave us the
short answer is whenever you see shark
biologists working up an animal if
they're doing it over the side of the
boat with the shark still in the water
they probably got it flipped upside down
and that's because sharks have a natural
tendency to go into like a trance state
when they're flipped upside down
biologists call this tonic immobility or
the tonic immobility response and
essentially what this does is it calms
the shark down it doesn't put it to
sleep
per se the way that you or I would sleep
but it does make it much more calm and
much easier for us to work with that
animal so by turning an animal shark
upside down we can let it calm down for
a minute or two and get our work done a
lot faster than if we had it right-side
up now this doesn't work all the time
it's a general response in sharks but
every once in a while you get an animal
that does not want to go into tonic immobility for one reason or another and
in those cases we won't wait forever
we'll put the animal back over and get
our work done as fast as possible but
the good news is most of the time it
does work and we don't have to use
chemical tranquilizers like you have to
do with mammals or with people going
into a surgery like we have to deal with
sharks so it's really really convenient
that we have this tool
that is basically built into the biology
of the animal that allows us to work
with them quickly without putting any
additional chemicals or anything like
that into their body
we don't always work with these animals
on the side of the boat though sometimes
if they're really small we can bring
them on board and we can do the same tonic immobility or if they're
really large we have to bring them up on
a lift or bring them up on a sling
depending on the research vessel we're
using in those cases it's really hard to
do tonic immobility because the animals
are so big so instead what we do is
we'll put a towel over their eyes to
calm them down and then we'll flush
their gills with seawater hoses so this
keeps nice oxygenated water flowing
through their gills it keeps them calm
it keeps them healthy and then we just
do the science as fast as we possibly
can so we can put those animals back in
the water and get them going on their
way but it's a really neat feature that
sharks essentially have an off button
that you can use by flipping them upside
down okay got a couple questions coming
in so we've got a question about sharks
that give birth and the different ways
that they give birth and it turns out
that sharks and rays actually have a
couple different methods for giving
birth some sharks and rays need egg
cases and those will develop outside of
the animal and then the young shark
or ray will hatch nowhere near the parent
sometimes you have for some species you
have animals that will actually develop
inside an egg in the womb and then will
essentially hatch inside the parent the
mother and then we'll continue to
develop and in some cases we have
animals that will actually gain their
extra nutrients once they've hatched by
eating eggs as they're made in in the
female reproductive tract we also have
some sharks that will actually go one
step further and will eat their litter
mates before their litter mates are
even born so this is something that
happens quite famously in sand tiger
sharks where you'll have multiple pups
in each uterus for the female but only
two babies are usually ever born because
the two biggest ones, the ones that
essentially become the apex predator of
their micro environment will actually
eat their siblings so they get the
energy to grow faster and so even though
it's really messed up from kind of
ethics perspective it helps the sharks
survive because when they leave the womb
they are in better condition, they're
bigger, they've had more calories and
they're better able to make it to
adulthood
than say if you cast out eight really
small pups that might all die within a
week or two weeks so the point is is
that sharks and rays with a lot of
different adaptations for surviving
and for making maximum reproductive
success and they're really really
fascinating I've got some other
questions here about shark intelligence
and there's a really intriguing one by
Annie cats about vocal cords and the
brain in sharks and specifically whether
the ability to vocalize makes animals
smarter or not sharks are not known for
their vocalizations but they're all they
are very intelligent animals we've known
for decades that they can be trained
they can do associations so they can
understand cues that lead to food or
that can lead to other things that
they're looking for so they're smart
animals that are able to learn so just
because they can't vocalize doesn't mean
that they're not intelligent but this is
an interesting question because it kind
of asks a broader question of what
dictates whether an animal is smart or
not sharks included now the very, very
general broad brush strokes predators
tend to have a greater need for
intelligence than herbivores this
shouldn't be terribly surprising because
herbivores usually don't have to chase
down their food they can simply go and
graze where they need to go predators on
the other hand have to catch usually
somewhat intelligent prey
and the penalty for failing is
starvation so it really is adaptive for
predators to be quite smart but this
gets bumped up another level with
sociality so predators that are social
whether they're mammals or birds or
invertebrates have an additional level
of need for intelligence because not
only do they have to learn to catch prey
and to handle prey and find mates but
they also have to be able to raise young
and navigate a social environment where
their fellow individuals might be quite
hostile to them so having that extra
need generates a lot of adaptation for
intelligence and while a lot of these
species we think of as intelligent do
vocalize you can think of crows or
ravens bottle nose dolphins are a very
common example you know they all create
sounds but there are also predators that
don't create sounds that are also very
intelligent and social my favorite
example would be cephalopods they don't
need to make sound in order to
communicate in the case of cuttlefish
they're actually able to communicate
through patterns on their skin that they
can change with special pigment cells
called chromatophores and you can go to
a lot of larger aquariums and actually
watch this happen I was at the Monterey
Bay Aquarium about a year ago and
there's an excellent cuttlefish display
there and I sat for probably a half hour
just watching these cuttlefish
communicate with one another without
making a single sound so you know
intelligence is not something that only
has to happen in mammals it doesn't only
have to happen in things that vocalize
but it does tend to be more common in
predators and it does tend to be more
common in social printers most sharks
are not terribly social they might
gather at certain areas like undersea
mounts, in large feeding aggregations and
then some species will also go into big
groups to mate but in general sharks are
not terribly social that being said we
still know that they're quite
intelligent that's a really interesting
question no one's ever asked me
one before so I hope that explanation made a little bit sense let's see
what else have you got
I see we've got some cephalopod lovers
in the audience
I love cephalopods: octopus, squid,
cuttlefish they're absolutely incredible
animals I'm pretty sure that if we
weren't at the top of the chain that
they'd probably be pretty close behind
us we've got a question about vibrations
from Anna Maria about whether vibrations
can irritate a shark's nose well in
terms of vibrations it helps to be a
little specific because sound is
actually just vibrations going through
matter so you can make the argument you
know just sound her shark's nose or not
but in general sharks have really
sensitive sensory biology up here in
their face sharks have seven senses not
the five we get who will they have the
five we have but they have two
additional ones and one of them is the
lateral line along their body and that
allows them to detect pressure waves
like these vibrations so at long
distances or medium distances this can
actually be very helpful to a shark
because the vibration that goes through the
water when a fish struggles at the
surface or maybe is swimming erratically
can send off a sense to the shark that
something is weird and that they might
want to go check out the source of that
disturbance but sharks also have an
electro sensitive sense up here called the or that's generated by structures called
ampullae of Lorenzini there are little
gel filled pockets in the snout of a shark
and if you ever take a close look at an
animal you can actually see these gel
filled pockets and so they detect
electro signals and they can be used to
find prey that are hidden in sand or
they can be used to detect whether an
organism is alive or not because we all
give off electrical signals that sense
though is really sensitive and it can be
overwhelmed through strong magnetic
fields or
through strong electrical fields so
certain disturbances can overwhelm a
shark's sensory biology and actually be
quite unpleasant for that animal and
you'll see some products on the market
that attempt to hijack this sense the
same way that shark biologist
essentially hijacked the tonic
immobility response to do our work and
they try and generate strong electric
fields around divers or snorkelers to
keep sharks away from them
the idea with those products is that
they're gonna overwhelm those ampullae
and make it really unpleasant for the
shark to be around that area I've never
used them before I can't attest to
whether they actually work or not
but that's the general idea behind the
biology so a couple other good questions
question about me from Matt Souza about
Mote Marine lab and whether allows and bring
populations are changing due to human
activity whether we're looking at that
and whether if there are any changes
whether this affects habitat
connectivity excellent pair of questions
so we do have multiple people working on
sharks at Mote Marine Lab in case you didn't
see our our logo is a shark because our
origin is in shark biology back in the
50's with Eugenie Clark often known as
the Shark Lady I'm not the only shark
person working here we have Dr. Bob
Pewter at the Shark and Ray Conservation
Program he's the head we have Jack
Morris we have myself and we have a
long history of having shark biologists
at Mote including current people
like Dr. Carl Luer and former people like
Dr. Nick Whitney and Dr. Jim Gelsleichter
slaughter who are have moved on to other
positions elsewhere my work is starting
to look at shark population fluctuations
in the Florida Keys but one of the
reasons one of the things we have to do
before we start that is get a baseline
sample so one of the things that I've
been working to get up and running this
year is actually have a standardized
shark fishing program here at Mote that
gathers the baseline data we need to see
long-term changes in shark community
composition, shark population and changes
in other things like shark size
or sex ratio or even things like the
chemical composition of their tissues
which can help tell us what they eat in
order to do that you have to be
collecting data every regular interval
say once a week for a long period of
time we're actually partnering with the
Boy Scouts of America to get this done
because the Boy Scouts have a large
operating base right next to us only a
few hundred meters down the road that
caters to about 13,000 Boy Scouts every
year from around the country and around
the world
they'll come in. they get time on the
water, they learn how do fishing, they
learn how to do canoeing, they learn how
to do all these different ocean-based
activities but they also learn how to do
science
so the Boy Scouts are getting more and
more interested in science technology
engineering and math and so we're
partnering with them to use their
vessels, teach the Boy Scouts why this
sort of monitoring is important and that
would bring the scientific expertise
from Mote so that we can start getting
these baseline samples but I have worked
on this in the past for my PhD one of my
questions was trying to figure out how
big disturbances to ecosystems can alter
shark populations now in general the
biggest threat to sharks and the biggest
cause of their decline is fishing
unsustainable fishing
it happens all around the world and it's
driven by a lot of different things some
times it's people just trying to feed
their families local fishermen going out
and just catching enough to eat and
other times it's industrialized
operations for either shark meat markets
or there bycatch in tuna fisheries or
other fisheries or they're for the shark
fin trade there are sustainable shark
fisheries but the level of unsustainable
shark fisheries around the planet is
putting substantial pressure on sharks
and causing a lot of these populations
to decline quite rapidly this is one of
the reasons why we need to do this sort
of work that Matt's talking about
looking at populations over time in
addition to fishing, sharks are also
vulnerable to other disturbances
including habitat loss this is one of
the things that I looked at for my own
PhD and I didn't do my PhD work in Miami or in the Keys I actually did it out in
Western Australia where we had a really
large marine habitat known as a seagrass
habitat that had declined heavily over
the course of my PhD sea grasses are
kind of like underwater grassland so you
can imagine a big field out in Kansas or
somewhere supporting all of these large
herbivores and all the things that eat
them and then imagine it all went away
say there was a large fire and there's
no more grass left I want to know how
that affects not only the things that
eat grass but the things that eat
those things which in this case was
tiger sharks tiger sharks are one of the
biggest species of shark
they're giant generalists they will eat
pretty much anything they can get their
mouths on and so it was an interesting
test to find out whether such a
generalist predator that's so adaptable
and able to go almost anywhere and eat
almost anything would be affected by a
disturbance like this and what we found
was that the number of tiger sharks
didn't really change after this big
resource loss even though we lost
thousands of square kilometers of
habitat but what did happen was the
number of sharks that we caught changed
their diet so they're usually quite
generalist predators and what we found
is over the course of time that general
diet that they had was getting narrower
and narrower and narrower presumably
because the number of food options they
had was getting lower and lower and
lower so even though the number of
sharks didn't change other aspects of
their biology did and this is something
that we need to look closely at because
you could just look at the number of
sharks and say there's no difference so
obviously they're resilient to things
like this when in fact things can be
happening in the background that can be
warning science going forward that we
need to be looking at now one of the
things that sharks do that gets to Matt's second question is that they move things
around so if a shark eats prey in one
habitat say in a coral reef habitat and
then it moves to a seagrass habitat or a
mangrove habitat and then it gets rid of
that excess nutrients it's now moved
matter from one
habitat to another and this connects
these habitats together not only does it
do that through matter but it can also
do it by changing the behavior of shark
prey sharks can change the way that prey
behave around them they can cause them
to move to new areas they can cause them
to eat in one area versus another so
they have these cascading effects
throughout the ecosystem and based on
how the animals that sharks would eat
move and how they change their movement
and their eating patterns can also alter
how habitats are connected with one
another so at the end of the day
ecosystems are a tangled web of
interactions and sharks play a central
role in a lot of these ecosystems
because they're these big predators they
can move things around they can cause
other organisms to move around and that
can change how habitats are connected
that's another thing that I'm looking at
and that I've looked at in the past
we've got a lot more questions here that
were phoned in beforehand I've got let's
see which which one should I pick okay
here's one that's kind of related to
what we just had Max Katz wanted to know
how sharks can help ecosystems recover
from disasters and I bring this up
because this is another thing that I
studied during my PhD we were just talking
about ecosystem as a net everything
is connected so sometimes the things are
connecting very weakly but sometimes
those connections are strong and when
they're strong and we don't know about
them we can get these nasty ecological
surprises when you take out one piece
you didn't realize how important it was
everything else rearranges and sometimes
it collapses and when that happens we
get really nasty surprises that can be
really hard to reverse one of the more
interesting things that predators do is
they generate these cascading effects
that can have surprising implications
for things you would never associate
with the predator in the first place for
example probably the most famous example
of this is Yellowstone National Park
where gray wolves were reintroduced in
the 1990's they had been gone for decades and
one of their main prey
elk
had been growing in population and eating a lot of the native vegetation, changing the
way the landscape formed for example the elk were eating a lot of saplings, small trees,
bushes, shrubs, etc. before they could get
tall enough to escape the elk's reach and
so as trees fell the new trees weren't
coming in to replace them landscape was
changing in the 1990's gray wolves are
reintroduced and while they did eat elk
they also caused massive changes in
elk behavior because areas that elk
would normally never worry about
predators they all of a sudden had to
worry about predators again and so they
stopped using certain areas of the park
as much as they were before and as a
result the vegetation started to change
now this is the most famous example of a
trophic cascade but it's not the only
one this happens in freshwater
environments, it happens in lakes, it can
happen in the ocean, it happens on land
elsewhere around the world but one of
the interesting implications of this is
that not only can predators alter plant
communities even though they never eat
them but it can also alter how plant
communities respond to disasters so
think about the Yellowstone example
again but imagine now we've burned down
half of the park and there's no
vegetation that's alive anymore except
for all of the seeds that are below
ground let's say we burn that all down
there's now no resources for any of the
elk and these saplings start to come up
these new trees they now have tons of
nutrients they have tons of light this
should be a great environment for them
to grow but if you have a bunch of
hungry elk that never have to worry
about predators and only have to worry
about where they're going to get their
next feed then all of a sudden these
saplings have a big problem and that
ecosystem might have a lot of trouble
recovering from that fire because there
are just too many herbivores eating the
recovering trees if you kept predators
in that environment
all of a sudden elk have to make a
decision they have to choose between
whether or not they go into these
habitats and try and eat or whether they
just go elsewhere where they know
they're safer and just do their best to
keep eating and not starve and so even
though wolves might not be eating that
many elk they can do have dramatic
effects on how ecosystems respond to
disturbance
some of the work that I did in
Australia with the seagrass ecosystem I
was talking about shows these same
patterns and what we find is a lot of
the big grazers especially dugongs which
are a Indo-Pacific relative of manatees
if anybody's familiar with Florida has
seen a manatee or sea cow before dugongs
are very similar they're related species
they look quite similar they're about
the same size they're a little more oceanic
but they have to eat sea grass the
only thing that makes the major portion
of their diet and they also are afraid
of tiger sharks and so we went out to
the system after a lot of the seagrass
died and when a food was scarce and we
said okay we know dugongs will eat in
these areas when the predators are here,
we know that they'll avoid them when the
predators they'll go in these
areas when the predators are gone and
they'll avoid them when the tiger sharks
are here so what does this mean for what
the seagrass will do and we essentially
did an experiment where we took the
known grazing rates from dugongs and we
applied them all year round manually we
became the dugongs we went out with
trowels and spades and we did grazing
the way that dugongs will graze when the
tiger sharks are not there and we did
that even when the tiger sharks were
there and essentially mimicked a
predator free environment such as might
happen if there had been a fishery there
for a hundred years that had fished out
all the tiger sharks and what we found
is that when you don't have tiger sharks
in that system
the dugongs are able to graze enough to
actually flip the already hurt system
all the way over to a system with just
stand or very small seagrass cover and
this is something that's really hard for
that system to recover from and so it
shows kind of like the the wolf example
that predators can have really strong
impacts on things that you would never
associate with predators simply because
they alter the behavior or the numbers
of the species that are in between
predators and primary producers
understanding where this happens and
when it happens when it's important and
when it's not is really really critical
for us to get management right for
ecosystems because if we
say allow us to punt out or fish out all
our big predators we could get ecosystem
collapses that we were never expecting
and that otherwise would not have
happened because we took out an
important part of the equation that we
didn't realize was important the analogy
that I like to make is it's when you
start taking species out of an ecosystem
it's kind of like knocking supports that
from underneath the bridge but you're on
the bridge you don't know which supports
are the most important and which ones
might not be and you don't know when
you've knocked out that last important
support that was holding the rest of the
bridge up and at that point the bridge
falls and it's a lot harder to put it
back together than it is just not knock
down the supports in the first place so
in that analogy of one of my jobs is to
figure out which ones are these supports
are the most important, which ones are
less important and which one should we
focus on for management so in a nutshell
that's why predators are important in
this system and why they're important
generally and how they can do things you
might not expect oh it looks like Matt
liked that answer well I think that
sounds like a good segue into into kind
of career talk for marine biologists how
you get into it how you get good at it
how you succeed some of the challenges
there are a lot of misconceptions out
there about what a marine biologist does
and what the life is like so you guys
humor me I'd like to take a minute and
talk about that as I was saying when we
first started I'm from North Carolina I
grew up about 250 miles from the coast
and I had very little exposure to the
ocean environment besides you know going
to the beach on family vacations every
once in a while it wasn't until I had a
science class in middle school that
actually took us to a coastal
environment and had us take notes about
what we saw and propose experiments and
identify species that I realized that I
really like this stuff and so I went
back to North Carolina I thought to
myself okay what do I have to do to do
this for the rest of my life I was lucky
because the state of North Carolina has
a great school for marine biology
University of North Carolina Wilmington and so I went
there for college I focused on science
and biology in general and then I
graduated and I didn't know what to do
and I'm sure I'm the first college
graduate to ever have that feeling but
it was a really scary one to have taken
all this preparation and then not know
what to do next I got really lucky and a
friend that I was in college with that
was in my program got me a connection
and had me applied for a job as a
research technician so this is a
entry-level position where you're
collecting the data, you are running the
experiments that the laboratory leaders
are designing, you are mending nets, you
are cleaning mud, you are counting
oysters, you are doing all these
different things that need to be done
but usually take a long time and almost
always get you very very dirty it was
one of the most fun jobs I've ever had
in my life and I did that for about a
year as I was doing that I was working
with different laboratories on different
questions and just acting like a sponge
just picking up as much information from
as many people as possible and after a
couple months I realized I really like
this and I think I want to do research
for good and so I started looking to
graduate schools when you look into
graduate schools in the sciences a lot
of times what you'll do as you go in and
send emails to people whose research
you're like I did that I emailed
probably 30 people and I got two
responses I read up on those people's
work I applied for some funding, I was able
to get it and I joined a laboratory at
Florida International University with
Dr. Mike Heithaus looking at the way
that predator's prey in their
environment interact to shape the
ecosystems we see but I got really lucky
at every stage of that process I got
lucky that I was in a school that took
me on that field trip, I got lucky that I
had a friend who thought of me when
there was an opening at the University
she was at, I got lucky that I got that
message in time and put in an
application
I got lucky that the year I wanted to go
into graduate school the laboratory head
that I wanted to work with had an
opening, I got lucky that I was able to
get funding for my research so you know
passion was an important part hard work
was an important part of that process
but luck was a really important part of
that process too if you're thinking you
might be interested in science and
you're thinking about graduate school I
highly recommend that you take some time
to work in a laboratory if you can if
you if you're able to swing it and you
can't find a paid position and can
volunteer even only a couple hours a
week that's really helpful too
but then when you're ready for graduate
school start looking at people's
websites start looking at the papers and
the research they produce try and figure
out what really excites you and gets you
up in the morning a lot of people have
this misconception that marine
biologists spend all their time on the
water they're you know lying on the
beach at the end of the day with a drink
in their hand and you know it's it's all
rainbows and jumping on turtles and
talking to dolphins and all this stuff
and in reality it's a lot more rigorous
than that you have to really really want
to know the answers to the questions
you're asking to keep you going and it
is a lot of fun but it's also a lot of
hard work and if you're not scared of
that you can do really well but it's
important to know what is actually
happening when you're going into this
field for example when I'm in the field
when I'm doing fieldwork I'm on the boat
almost every single day and a lot of
biologists do field work in what we call
field seasons so they'll take part of
the year maybe the three months during
summer they'll go to wherever they
normally do their research could be down
the street or it could be across the
planet and they'll spend every day on a
boat doing whatever research they're
doing but that remaining nine months or
six months or however long it is they go
back home and they write or they work on
analyses
or they teach or they develop new methods
and that's the thing that you don't
often hear people talk about when they
talk about marine biology my average day
looks like this I'm in my office I'm
writing up results to share with other
scientists or I'm applying for money to
fund my work or I'm doing outreach I'm
answering people's questions and talking
with people about science and sharks and
sea grass and everything in between but
you know not everybody understands that
the average day for most marine
biologists is probably in an office or
in a lab but at the same time that's
really cool because this is where the
answer the questions get answered this
is where we take all that information
that we get out in the field let me
bring it down bring it on to a computer
or we put it down on the desk and say
how does this fit together
and the ability to answer a question
that somebody has maybe never known
before ever in human history and say I
did this because of the way that I did
science is a really really cool feeling
and that's the thing that gets me up in
the morning but for each person it's a
little bit different let's see
Christopher Gentry has a question are
there any studies that have examined
changes in preferred shark habitat and
range with changes in sea surface
temperature yes so you're mentioning
bull sharks down further north than
usual which sounds a lot like my friend
Chuck's work there are absolutely
changes in species ranges happening
worldwide with increasing temperatures
and with changes in the seasonality of
temperature it's happening on land it's
happening in the ocean and we're getting
better and better at measuring now in
general it's harder to do work in the
ocean than it is on land simply because
for one thing you need a working boat
engine to even get out and start
collecting data a lot of the time and so
there are a couple more barriers you need
good weather you need usually more money
you need at least a little bit of
engineering know how to get out and
start
your work but even now we're able to
determine that species are moving
further and further towards the poles in
pretty much every main type of habitat
this has some really interesting
implications for the ocean because if
you look at the way that coastlines move
and are shaped in some places we're
generating funnels and we're generating
dead ends that species are not going to
be able to escape from so for example
think about the Gulf of Mexico it's a
big cup basically at the top it ends
with the Gulf States and if a species is
at the absolute southern end of its
range there and it can't possibly get
any warmer there's nowhere to run to
it can't go north because if it goes
north it's gonna hit land and so we have
these certain areas where as the waters
warm species are gonna get squeezed more
and more and more and in some cases
they're going to disappear that's a
really big concern because for a lot of
these species they either have a really
important environmental role to play or
there's something we love to put on our
dinner tables or see an aquarium or
multiple functions like that and so
understanding exactly how fast these
changes are gonna move exactly what's
gonna happen when new species meet each
other that never met before and how
that's going to shape ecosystems and how
humans use ecosystems is a really
fascinating problem and something that
we have a lot of people working on and
it's not only North America that that is
thinking about these things the
Mediterranean has a strong east to west
border with Europe as things warm up
those animals are going to have trouble
moving plants and animals are gonna have
trouble moving north Australia has a
very similar problem the south coast of
Australia is fairly flat going east to
west
but the continental shelf to the south
of that falls off and it gets quite
deep so there are some species there
that are already probably pretty close
to their warm water range that have
nowhere to run because there's no more
shallow coastline to the south of
Australia so these are really important
questions
and what's really critical is we're
seeing these patterns now we're seeing
fish move now we're seeing sharks move
now we're seeing insects and plants and
birds and mammals move now it is
happening in our lifetime and it's
happening even on the course of a couple
of years it's really really fast thanks
for that question that was good one so
Erin Daniels wants to know about red
tide we haven't seen any effects of red
tide down here down in the Keys we've
got a bunch of open water between us and
the west coast of Florida through
Florida Bay and outer Florida Bay so we
do have a red tide monitoring program
down here we're not picking up a red
tide but you know it's been happening
for hundreds of years at some point it
might happen again in the Keys but right
now we've got beautiful water no red
tide warnings nothing to worry about
there let's see what else you guys have
good questions so Victoria wanted to
know how much food does an average shark
eat in a day the short answer is it
depends the long answer is a little more
interesting
in general sharks eat between 1 to 5
percent of their body weight per day
that depends greatly on the species of
shark, the temperature of the water, the
quality of the food, whether the shark is
growing, whether the shark is pregnant
and trying to feed pups, etc. etc. so
there's just like people a big variation
around that range 
and sharks don't need to eat every day
in fact a lot of them don't eat every
day they can eat every other day or
maybe even every week but they're slow
to metabolize unlike humans most sharks
have a fairly slow metabolism and most
sharks have a body temperature that
mimics their environment and so if you
are a deepwater shark that lives in 39
degrees Fahrenheit of water you can go a
long time without eating because your
metabolism is so slow you're burning so
few calories that you can really sit and
be very energy efficient you're not
going to win any races and
you're not going to grow very quickly
but some animals especially in the deep
sea are able to go a long time without
eating because their whole lifecycle is
just really slowed down one of the most
interesting things about metabolism in
general is that it scales with body size
and this is one of the few beautiful
general patterns in nature in life that
really helps drive the way that animals
and plants and ecosystems work together
so for example an elephant an African
elephant weighs thousands of kilograms
whereas a mouse might only weigh 20 or 30
grams so you can put on one side of a
scale in African elephant on the other
side of the scale thousands of mice and
they don't eat the same amount of food
even though they weigh the same amount
as you go up in size you do need more
food but the amount of food you need per
kilogram goes down this is called
metabolic scaling and so those say
10,000 mice will actually eat a lot more
food than that single elephant even
though they're the same exact weight and
this happens in all animals that happens
in sharks as well and so even though a
smaller shark will need to eat more than
a bigger shark sorry it needs to eat
less than a bigger shark the amount it
needs to eat per kilogram is actually
higher and anybody who has children
probably is not surprised by this at all
you can eat you out of house and home
part of that is because kids are growing
but also your per kilogram metabolic
rate is higher when you are smaller so
something that underlies a lot of how
plants and animals work but not a lot of
people think about explicitly is how
metabolism changes depending on how big you
are let's see
Roger Muller wanted to ask a question
that I think shark biologists get a
lot and have been getting a lot more in
the past couple years and that is is
there possibility that Megalodon is
still alive well I'll give the short and
the long answer the short answer is no we
know for a fact that
Megalodon is no longer around but I want to
kind of to use this as a thought
experiment for you all because there are
a lot of species that are no longer
around that we don't ask this question
about for example in North America we
used to have giant ground sloths just
running all over the place these were
huge animals with giant claws and they
were part of a period in North America's
history where we have all sorts of wacky
mammals running around eating each other
and basically making paleontologist's
careers very interesting but nobody ever
asks you know do we know if the ground
sloth is really extinct or not and if
you think about why that is shouldn't be
that surprising we don't see giant
ground sloths on the news we don't see
trees toppled over with giant claw marks
in them all throughout the Appalachians
we're not finding you know new
carcasses of giant ground sloths and the
bones that we do find are fossilized and
all of these things together tell us
that not only are giant ground sloths no
longer around but they haven't been
around for a while because we can tell
how old these bones are or how old the
fossils are the same story is true of
Megalodon we don't find whales with
giant bite marks at them and we are
pretty sure that Megalodon was a whale
specialist predator we don't find
Megalodon washed up on the beach even
though we can find really really rare
marine species washed up every once in a
while or even have video of them we've
never had that with Megalodon ever but
probably the most damning piece of
evidence to tell you that Megalodon has
been gone for a long time is its teeth now
you can find Megalodon teeth in a lot of
places around the world there are famous
beaches in Florida, North Carolina and
South Carolina where you can find
Megalodon teeth either inshore or
offshore but the pattern there that's
important is that these teeth are always
fossilized they're never new they're
never fresh they're never even close to
fresh the youngest ones we found are
probably still about a million
years old and you would expect if there
were even a couple Megalodon anywhere
around the world that we would have at
some point some evidence that they were
still around and we have absolutely no
evidence of that
so I can safely tell you Megalodon is
no longer around it went extinct about
one to three million years ago and one
of the prevailing hypotheses for how it
went extinct you actually need to blame
Panama
so the Panama isthmus that links North
and South America together didn't used
to exist it's pretty new actually it's
only a few million years old but before
that land bridge was there there were
ocean currents that ran between South
America and North America now ocean
currents can have a really strong effect
on how land and water behave what the
climates are like for example if you
look at the UK to how far north it is
and then compare that to Canada it is
amazing at first glance that it's not
completely covered in ice all the time
one of the reasons for that is because
the Gulf Stream the warm water current
that runs along the East Coast of the
United States comes up and brings warm
water warmer than it should be over to
Europe and helps keep the climate
temperate for the United Kingdom those
currents can have really strong impacts
on life as well now remember we were
talking a few minutes ago about sharks
and how they're ectotherms they adopt
the temperature of their surrounding
environment at least generally some
species aren't able to keep an elevated
body temperature but in general they're
not like us they're not like seals or
dolphins that always maintain 98.7
degrees no matter their surrounding
environment they fluctuate a lot with
what that environment does and that's
important because Megalodon as I said a
minute ago we believe was a specialist
predator on whales whales are endotherms
they're mammals they're warm-blooded
they can keep that body temperature with
those thick blubber layers even in very
cold water if you look today many of our
whale species either exclusively use
cold water or at least use it for a
large part of the year Megalodon would
have a lot of trouble keeping up with
that and so one of the general
hypotheses as to why Megalodon went
extinct is because when that isthmus
started to close and ocean currents
reset they essentially pushed whales to
the poles and the Megalodon was not able
to maintain its temperature follow into
those colder waters and to keep eating
its prey it basically became a mismatch
kind of like what you're talking with a
little while earlier Christopher with
animals changing habitats this has got a
really strong implication for Megalodon
now this is not the only hypothesis
there are also hypotheses that Megalodon
lost its nursery habitats for
its young and the jury is still out on
exactly what happened
paleo ecology which is understanding the
ecology of extinct ecosystems is an
exciting and incredible field of science
but it's really hard to answer questions
and so as time goes on we're going to
keep getting more information to help
solidify what happened to Megalodon
but what we can all agree on is it's not
around anymore and that makes me feel
honestly a little bit better when I'm in
the water because I really love sharks
and I am not afraid of them I had a
healthy respect for them but a 60-foot
predatory shark is something that I
could probably do without seeing in the
wild but that's just my opinion I'm sure
a lot of my colleagues would be
absolutely ecstatic to see something
like that and you would absolutely see
it on YouTube if it was around let's see
what other questions do we have for
folks so we've got Max wanted to know
whether it's possible to track whale
sharks because they're so large and when
we talk about tracking sharks what we
mean is putting a tag on them and electronic
tag that either tracks where they move
horizontally around the world where they
move vertically in the water up and down
or both and the short answer is yeah we
have tracked whale sharks
and it's hard to work with them in a
traditional sense because they're so big
you can't bring them onto the side of
the boat but what you can do instead is
go up with fast vessels and actually
attach the tag while be whale shark is
swimming and anytime that whale shark
comes near the surface and the tag
breaks the surface of the water it can
talk to any satellites that are around
similar to the way your your phone does
when you come out of a tunnel and it
will tell the satellites hey I'm right
here
those satellites will go and talk to the
scientists and say we found your tag
it's right here we bet your whale shark
is right underneath it and over time we
can see where whale sharks or white
sharks or tiger sharks or bull sharks
move we know where they use big areas of
habitat well know if they do migrations
or not we might know if they return in
the same area every year or if they just
kind of hop around the different
habitats
so this tagging technology is really
incredible for helping us understand
where animals move and it is able to be
put on whale sharks we have some ability
to put them even on whales with really
clever use of very long poles and
suction cups so in general if the
question is can we track it someone is
either already said yes to it or is
probably working on a way to track it so
we can absolutely do that with whale
sharks - let's see what other questions
that we got so I had somebody ask if
there's a difference between a marine
biologist and a marine ecologist and the
short answer is yes and no so I am both
I am a marine biologist and a marine
ecologist marine biologist is simply
anyone who studies life in the oceans so
this could include a marine geneticist a
marine phytoplankton biologist marine
shark ecologists well that's a little
bit superfluous you just say shark
biologist but anybody who studies life
in the oceans is marine biologist
that being said not many marine
biologists actually use the term marine
biologist because it's not very specific
it's not a very helpful title to use I
use the title marine ecologist because
it's more specific to me I study how
different organisms interact with each
other and with their environment to
shape ecosystems I study at the
ecosystem scale not just sharks not just
seagrass not just phytoplankton I study
multiple species and that makes me an
ecologist if someone only studied shark
biology they would be a shark biologist
but they would also be a marine
biologist so when people say I'm a
marine biologist you should ask them
what they actually study because that is
an absolutely huge field and you can
have a really wide variety of scientists
that are all marine biologists but study
completely different things so I had a
couple questions from Izzy and a few
other folks about what life is like when
you're on a research vessel when you're
at sea and doing work not just
day-to-day trips but actually there
overnight going into the next day etc.
I've had the opportunity to be on a
couple research vessels each one I have
found is quite different but they all
have some things in common first and
foremost probably not surprisingly
research vessels tend to be bigger than
small day vessels they have to be because
not only do you need more fuel but you
need more radio equipment you need
places for people to sleep you need a
lot of other things you don't need if
you're just going out for the afternoon
so research vessels tend to be several
times bigger than your typical small
boat for me a small boat might be 18
feet 25 feet a research vessel
could be a hundred and 25 feet or 200
feet it depends on the boat but they can
be quite large they are fully equipped
as well so if we go out on a research
cruise for 16 days for example you would
leave and when the ship leaves it needs
everything that it's going to need for
that 16 days already aboard this means
water it means food
it means fuel it means spare parts
scientific equipment or anything else
that we might need on that boat for the
next couple weeks it also means that we
have to be well regulated with our
logistics and understand exactly how
much we need to consume on this day in
this day and this day to make sure that
we don't run out of food but also so
that we don't pack too much because
space is at an absolute premium on boats
and so when you're on a research vessel
things can be very regulated you wake up
in a certain time you would achieve your
objectives at a certain time the boat
knows where it's gonna be at a certain
time so you have to go to a certain
place at a certain time you eat meals at
a specified time you go to sleep at a
specified time you take showers at a
specified time it's very rigid because
not only do we have a limited amount of
resources but we also have a schedule to
keep in general research cruises which
are more than one day on a research boat
are very very expensive so we might have
10 different science teams doing
different projects each one trying to
work when the other ones are asleep or
when the other ones are processing
samples so that the boat is doing
science as many hours of the day as
possible
in as many different places as possible
if there's one thing I can say is
probably true of research cruises in
general it's that nobody sleeps as much
as they want to there is far too much
work to be done and everybody always
needs a hand your fellow scientists are
always needing help and so at the end of
that research cruise everybody tends to
be really worn out but if you've got
lucky you got lots of good data and when
you get home and sleep in your own bed
it is the best sleep of your life it's
really fantastic see a few more are you
guys still with me can you still hear me
and do you guys have any more questions
is there anything that I explained bad
that or poorly that you want me to go
over again awesome excellent you guys
want to know a fun shark fact this is my
absolute favorite fact out of everything
all the facts out there this one's the
best sharks are older than trees are
sharks as a group evolved about four
hundred million years ago and they got
the jump on trees for a couple tens of
millions of years so when you think
about what ancient life looked like back
then the land had very primitive plants
just starting to get insects look
nothing like it does on land today but
the ocean still had some pretty familiar
organisms if you look at fossil shark
reconstructions from even back then you
can still pretty much tell what they are
and I find that really incredible and I
also find it really humbling it makes me
realize how important the job is of
marine conservation and shark
conservation because we have animals
that have been around for so long that
they predate things that we kind of
think of as ancient and they're still
recognizable today and they're imperiled
today in a way they've never been
imperiled before and so this sort of
work doing conservation doing science
understanding what's happening in
ecosystems so that we can manage them we
can predict what's going to happen in
the future so we can have these
organisms for our children and our
grandchildren you know hundreds of years
into the future it's really important
it's tough though doing science is hard so
sometimes you need those little fun
facts that keep you going when you're
wondering why your experiments have
failed and why the boat won't start all
these other things that sometimes happen
ah okay cool we'll have the chat later
I apologize Chris if I've done any super
simplification that misses the mark I
should say that I'm an ecologists not a
well not a bunch of other things so do
take some of the things I say with a
grain of salt the best thing to do in
general when you speak with people and
they tell you things especially if
they're really surprising things is go
verify that information always be a
critical thinker always be thinking
about what the next implication of what
you learn might be and make sure that
you're always making sure that what you
hear is actually true and a lot of times
you'll figure out some interesting stuff
you didn't know before and every once
in a while you figure out something that you
thought was real isn't and then
everybody ends up smarter at the end of
the day so I think that's about it guys
just about two o'clock
I've really enjoyed speaking with you
all I've enjoyed the questions I got
that's some really good ones I
especially like the one about vocal
chords and it's always good to see my
old friend the Megalodon question again
you can reach me at Mote Marine lab and give me
one minute okay when I said you can
reach me I didn't mean right this second
I don't know who that was but if you're
interested in learning more about sharks
or if you have any questions for me that
come up later you're welcome to reach
out to me I'm on Twitter where I'm at
Robert J Nowicki or you can reach out to
me through the Mote.org  website and you
find me easily there my emails up at
Rnowicki@mote.org so if you have any
further questions please reach out I'm
always happy to answer if you guys are
interested enough to sit here and ask me
questions and listen to me
you know blather on about stuff I'm more
than happy to spend the time talking
with you but anyway I think that about
wraps up our time so I really do
appreciate you guys staying with me and
being so engaged and this was fun I
really look forward to being able to do
it again this isn't the only talk that
Skype a Scientist is doing we've got a
lot of other great ones that are lined
up I say we I it's not me it's Skype a
Scientist that's doing it but you can
find that schedule on Twitter and
anywhere else Sarah that people can find
additional Skype a Scientist meetings
beyond this YouTube channel okay
excellent and two more things before I
go
first of all Bryce wants to know are we
working with local fishermen yes the
Shark and Ray conservation program
especially works heavily with local
fishermen fishermen have really deep
knowledge they're out on the water all
the day all the time often every day in
a way that we scientists can't be
and so fishermen and science
partnerships are really powerful because
they bring two kinds of knowledge to the
table and when those people are willing
to work together we can get a lot more
done than when we fight with each other
so yes mote does work with local
fishermen the shark and Ray conservation
program works with local fishermen
they're great folks they've got a lot of
knowledge and at the end of the day we
largely want the same thing we want to
be able to keep going fishing and keep
having an ecosystem that works right
well into the future so yeah we do
definitely work with that as for Matt
research technician positions at mote
are not just for people who just got out
of undergraduate studies we sometimes
have high school students we sometimes
have people that are still in
undergraduate occasionally we have
master's students actually that will
come and work with us it's most
important to go reach out to the program
head that you want to work with and see
if they're taking openings and see what
kind of position they're looking for and
then I would suggest go from there but
there's no hard and fast rules about you
know the age of an applicant
how far they are in their career anyway
that's it I've gotta go but I really
appreciate your time and you can see
there's a bunch of links here so you can
insert or ask more questions through
that thank you all very much
see you later
