Diving

A plea to new spearo’s

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A great weekend diving with friends was somewhat tarnished by the actions of a naive spearfisher. We were unfortunate to witness a spearo enter the water in a sanctuary zone (no-take zone) and spear a blue wrasse, a protected species in NSW.

Spearfishing is a great way to get some fish into your diet. It can be a great challenge learning to freedive and learning to observe fish behaviour. That being said, there are no throw backs with spearfishing. Which is why I implore people new to the sport to know where you can fish and what species are ok to target. Do not pull that trigger unless you are 100% certain that the fish is of legal size and not protected. The fisheries rules are in place to help sustain our fish populations so that everyone can continue to enjoy our oceans.

Getting started can be daunting. It might seem like there are a lot of species to learn and there are. I would recommend tagging along with someone more experienced until you get to know your local fish. Join a spearfishing forum – there are often people looking for buddies. Failing that, get out and go freediving without the spear and look up the fish you see. In only a few dives you will quickly learn the common fish at your local sites. If you really want to get straight into it, consider deciding on a specific species to target before you even get in the water. Failing all of this, you can follow 1 simple rule: If you don’t know what it is, don’t shoot it. 

Some useful websites:

DPI Fishing rules – http://www.dpi.nsw.gov.au/fishing/recreational/fishing-rules-and-regs/saltwater-bag-and-size-limits

Marine protected areas – http://www.dpi.nsw.gov.au/fishing/marine-protected-areas

Spearfishing forum – http://www.spearfishing.com.au/sf-forum/

The Rapture of the Deep

DCIM100GOPRODeep diving is something that I am passionate about – especially if it involves a shipwreck. It is a chance for me to push my skills, training and equipment and to explore some of the lesser dived or known sites. However this comes at a considerably higher risk which involves specialised training and equipment to manage safely. One of these risks is Nitrogen Narcosis – aka “the rapture of the deep”. Not a lot is known about the causes of nitrogen narcosis, but it is a narcotic effect brought on by the increased partial pressure of nitrogen in the breathing gas at depth. The threshold for nitrogen narcosis is different for each diver and can even vary dive-to-dive within a diver, depending on many factors. I usually enjoy getting a little “narc’d”. It can be quite euphoric and enjoyable if managed well. Nitrogen narcosis itself is not dangerous, unlike decompression illness, and there are no long lasting effects – no nasty hangovers. What can be dangerous though is the impaired actions of the diver experiencing euphoria. It’s essentially diving drunk. Nitrogen narcosis, like other narcotics can also present as paranoia and confusion which can lead to panic. Bad news in any depth of water. Thinking about these effects, I thought I’d share a story I wrote about a dive many years ago where I was overcome by narcosis paranoia in the hope that others can learn from my bad experience. This dive was a huge learning experience for me and still serves as a source of healthy anxiety before a deep dive. Nitrogen narcosis is not something that can be (nor should be) avoided, but it is certainly something to be aware of.

Before I get into the story, I should also make a quick note about solo diving. This practice is often frowned upon in diving circles and I do agree that diving with a buddy significantly reduces many risks associated with diving. However, I also believe that with proper training and additional equipment, many of these risks can be minimised and solo diving can be conducted reasonably safely. The training that I have done to enable me to dive outside the recreational limits had a special focus on redundant equipment and self reliance in emergency situations. I personally find solo diving to be quite relaxing and enjoyable, but only because I take the necessary precautions when I do it (which isn’t often).

When 3 things go wrong…

“If you turn right when you get to the anchor you’ll see the boiler. Then if you go left from there, you’ll get to the stern section” said my buddy.

“No worries. Too easy”. I think to my self.

There are some days when you really should just stay in bed. I was gearing up to dive a wreck off Sydney. It was one of those magic days on the water, with the sun newly risen and barely a whisper of a breeze to ruffle the smooth surface of the ocean. Unfortunately this magic had been marred by the realisation on the trip out that I’d left the undergarment for my dry suit laying on the back seat of my car. Idiot! This was to be the least of my troubles on this dive. As I was gearing up, to my horror I discovered that my fins were no where to be seen. They too were laying in the boot of the car along with my ankle weights. The ankle weights didn’t really concern me, but without my fins I was resigned to being the boat boy. Shit! how could I forget my fins! The undergarment and ankle weights were no big deal, I could get by without them, but my fins! You Idiot! I cursed my self again.

My buddy has said on many occasions “when you have 3 things go wrong on a dive, any 3 things at all, call it off”. Hmmmm, fins, ankle wights, undergarment…. I should have taken that advice.

The two others on board rolled over the side and descended onto the wreck 50 m below. I watched them disappear into the inky blue depths. 20 minutes later my buddy reappeared on the surface. He was diving in a wetsuit and was getting cold so had called his dive short. He climbed back on board raving about the excellent visibility and the fish life. He suggested I take his fins and go check out the wreck. It didn’t take much to talk me into it, although I could hear his words (spoken to me so many times) going through my head “when 3 things go wrong….”. But I couldn’t resist. I had gotten up early and made the trip out here and I was grateful to him for the offer of his fins, giving me the opportunity to explore this wreck that I’d heard so much about.

So I turned on the air for my two back mounted tanks, checked my gauges and climbed into my harness. As I was attaching my stage tank (a 3rd tank containing a Nitrox mix to reduce the ascent time) my buddy described the layout of the wreck to me.

“If you turn right when you get to the anchor you’ll see the boiler. Then if you go left from there, you’ll get to the stern section”.

I was so excited by this stage as this was my first time on this wreck and the conditions couldn’t have been better.

“What bottom time are you going to do?” He asked me.

“I’ll just do 10 minutes” I replied, feeling safe in the knowledge that I’d previously planned a 20 minute bottom time with breathing gas to spare.

I donned my buddies fins, went through my final checks, rolled over the side and kicked below the surface to the anchor line.

Breathe in breathe out…. slow, even breaths. Equalize. The particles suspended in the water whiz past me as I descend. I’m dropping fast. Breathe in, breathe out, equalize. Check instruments: depth – 12 m, dive time – 0:00, air – 223 bar. Every thing looks good. I feel great! I love this part. There is nothing around me. The only reference is the anchor line in front of me, disappearing into oblivion. I feel like I’m in free fall.

The visibility at this depth is only 5 m at best. My descent continues. 15 m… 22 m… 25 m… The visibility opens up. I can just make out the wreck below me sitting in 50 m of water. The gunk in the water above me partially blocks out the sunlight. I turn on my torch, more for comfort than anything else. I’m breathing a little harder now with the increased pressure so I adjust the resistance on my reg and add some more air to my dry suit to slow my descent. as I pass through 30 m depth I’m still dropping fast so I add some air to my BC to slow my descent.

Instrument check: depth – 48m, dive time – 0:02, air – 204 bar. As I arrive at the bottom, I try to unclip my reel from my harness. My fingers are clumsy, I must be narc’d but I still feel fine. I get my reel free and manage to tie onto the anchor line. I take a couple of seconds to catch my breath and gather my senses. Breathe in… breathe out… Wow! I am narc’d! I can’t concentrate…. better check my gauges: 0:05 dive time. What happened to those 3 minutes! This is fantastic! The vis is at least 30 m! 3 huge trevally cruise past me glinting bronze in my torch light. I watch them disappear into the distance. I’m surrounded by wreckage covered with tiny pink, purple and white bryozoans. Orange and yellow sponges fight for space with iridescent algaes. A school of pomfret, glowing golden in my torch light, cascade over parts of the wreck. I’m loving it!

Ok, what was I doing?…. Turn right from the anchor…. Right or left? No it was definitely right…. Which way is that? Ok concentrate now… this is my right hand… turn that way. I see the edge of the debris field and sand…. Where is the boiler? I keep turning. There’s the anchor…. Ok, I’ve turned right around. maybe it was left…. Ok turn left…. Wreckage… Sand… Anchor. I’ve turned around again…. where is that boiler? it was definately “turn right from the anchor”…. Ok, calm down, breathe. Should I bail out? I’m really really narc’d and I feel like I’m really pushing my abilities. No I’m ok, I’m well trained, I’m using familiar equipment (apart from the fins), my skills are up to scratch and I have heaps of air… I can handle this situation. Stop, breathe, think and act. Breathe in….breathe out. Think: “turn right from the anchor…” Act. Ok…. turn right. Ok I see a shadow out on the sand…. Is that the boiler? All the way out there? Ok… Start swimming…. It’s hard work…. Bugger that. I’m not swimming out there. Turn around… Which way?… Oh yeah, that’s right, it won’t matter.

I turn around and reel my way back to the anchor. I’m so narc’d. I can’t think. Calm down…. Breathe…. Check instruments: dive time 0:08 minutes. damn! I’ve wasted most of my bottom time. Air – 182 bar. I can’t think straight.

I close my eyes to try to gather my thoughts. Breathe in… Breathe out… Ok…. I’m on the edge of the debris field. I’ll just follow the sand line for a little bit. Which way? There’s a slight current… I’ll just drift along with that…. No wait!… I tell my students not to do that in the open water course… But I only have 2 minutes left. I’ll just drift a little way, then turn around. It’ll be fine.

I move along the wreck with the current. There are some beautiful little gorgonian fans, and some little pink bryozoans. Three juvenile blue wrass scull along beside me…. This isn’t so bad… A little leather jacket moves out of my way. Wow! this is a beautiful wreck! There are scattered deck plates and beams all around me. I wish I could have found that boiler or the stern section. Ah well next time… Oh shit! what’s my bottom time? 0:10! Shit! Turn around. I swim into the current. It’s not strong, but I have to work harder. I can feel my breathing rate increase with the extra effort. I reel in my line as I swim back to the anchor.

Back at the anchor. Instrument check: dive time – 0:11 minutes, air – 156 bar. My computer tells me that I require a 4 minute stop at 6 m with a total ascent time of 13 minutes. It’s ok, I have plenty of air and a 40% nitrox mix in my stage tank. Ok… relax… I try to detatch my line from the anchor chain, but my fingers just won’t work the way I tell them to. Finally the line comes free (I was so close to cutting it). I secure the reel to my harness and begin my ascent. Dive time – 0:14. Shit! I stayed way too long. I’m ok, I’ve got plenty of air left. I make my way up the anchor line. not too fast….dump air….breathe in breathe out. Up I go… at 25 m (the safe operating depth for a 40% nitrox mix) I reach for the reg on my stage tank but unbeknownst to me, the hose is caught on the buckle. I pull at the reg, but it wont come free. I’m still going up… dump air…. breathe…. I’m thinking more clearly now. Ok stop… Breathe… Think: “why won’t the reg come free?…. It’s caught on something”… Act: follow the hose with my hand. Ok, it’s caught under the buckle here. Ok, there it goes. I pull the reg free and start to breathe my nitrox mix. Instrument check: Dive time – 0:18 minutes, gas – 200 bar, 10 minute stop now required at 6 m. I make the gas switch on my computer. it re-calculates my ascent profile taking into account the new gas mixture I’m now breathing. Dive computers are such wonderful things! 1 minute of decompression now required at 6 m, total ascent time, 7 minutes. I slowly make my way to my 6 m stop and wait for 1 minute. Up to 3 m for just 5 minutes (oh how I love nitrox).

Hanging on the anchor line at 3 m I have time to contemplate the dive. I was out of my depth (excuse the pun). It all started out wrong. I feel lucky to be back near the surface. Things could have really gone wrong down there. Well, actually, maybe I’m not lucky, per se. When I knew I was getting into trouble, my training kicked in: Stop, breathe, think and act. And I was able to gather my self sufficiently to be able to get back safely. Nevertheless, I’ve learnt some valuable lessons from this dive. I should have bailed out when I felt the narcosis become overwhelming. Always start the dive swimming into the current. Practice practice practice with your equipment so that muscle memory can relieve some of the task loading on your brain at depth. And especially “When 3 things go wrong…”

Shark!

Did that get your attention?

There has been a lot of media attention surrounding sharks recently, starting with that terrifying footage of Mick Fanning and a number of incidents on the NSW north coast. Following on from these incidents there have been calls from a very vocal minority of ocean users to ramp up efforts in shark control measures. It should come as no surprise that I don’t support lethal methods of shark control. As far as I’m concerned there are much bigger risks in life than the threat of being bitten by a shark. If we wish to enjoy the ocean we should know the risks and accept that we share this wonderful environment with these apex predators. However, with all of the media hype, it’s easy to forget that we also share the ocean with some other amazing animals, which is what I though I’d share today.

The beauty of the ocean never ceases to amaze me.

A small win for the PhD!

I had a small win this afternoon!

I’m back on Lizard Island at the moment and over the last few days I’ve been setting up an experiment.

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This experiment is to try to determine what factors might influence a subordinate individual’s decision to either stay within a group or to move out. I am testing habitat size and habitat saturation. To test these factors I have created groups of three fish (two adults and a subordinate) in medium sized corals. These groups of three are then presented with either a small, medium or large coral containing either 0, 1, 2 or 3 other fish.

Wow! that’s confusing when I write it all out. Here’s a diagram of my experimental design.

Experimental design

Over the last 48 hours Kaz and I have had the first trial running. In trial 1 the group of three fish were presented with an empty coral which was smaller in size. Last night the subordinate actually moved into this smaller coral. I can’t really draw any conclusions from this one trial, but if we keep seeing this happen, it could indicate that the degree of habitat saturation is more critical than the size of the habitat in determining whether a subordinate will stay or leave a group. In terms of group formation, it could indicate that groups are more likely to form when the habitat is highly saturated (i.e. when there are not many vacant corals). That’s exciting for me and my thesis 🙂

More info on my research

My research

Initial project report

Lizard Log series starting here

Lizard pics

Fish tattooing

Fish tattooing

Capturing the fishies

Capturing the fishies

Goby hunting.

Goby hunting.

Kaz shopping for corals

Kaz shopping for corals

Kaz measuring

Kaz measuring

It's not paradise every day...

It’s not paradise every day…

A Madagascan Adventure: Part 2

Part 2: Life as a volunteer

Picking up from where I left off in the last post, after our sojourn through the Madagascan countryside, our initial culture shock somewhat subsided; my fellow volunteers and I were finally in Andavadoake – our home for the next 6 weeks (for some of us, the next 12 weeks). Following that first hypnotic sunset, it was time to get stuck into life on site. Our living conditions were basic but comfortable, with huts situated right above a small cove called half moon beach. We’d wake to the sound of the waves and passing pirogues (wooden sail boats) heading out for the day’s fishing.

Beach Huts

Home in Andava

Our diet consisted of mainly fish, beans and rice, with a few variations on the theme from time to time, including the delicious Malagasy beef equivalent – zebu; The mighty zebu is also used to draw carts, plough fields and buy wives and is a precious commodity for many tribes in Madagascar. I couldn’t get enough of the fresh seafood, though we did miss the abundance of fresh fruit and veg we’re used to back home.

But basically, we were living in paradise!

Zebu

The mighty zebu

mackerel

Freshly caught lunch

A typical day consisted of 2 dives in the morning, many with whale sightings on our ride out to site, a stroll to the village for a cup (or five!) of peanuts, study/hammock time followed by duties, lectures, presentations or language lessons then dinner and ‘tantara’. Tantara roughly translates to ‘story’ in English, and we all took turns to tell a story, run an activity or game, show some pictures etc. for our evening entertainments

A typical week was diving Monday-Friday, Saturday land based activities like visiting mangroves or learning to cook samosas and boko boko (deepfried dough filled with chocolate – yum!), followed by a night of shaking our butts Vezo style in the local bar, Dada’s… the Malagasy’s put us Westerners to shame! Those guys can seriously move. Sunday was our day off where we got to go exploring! We embarked on baobab walks, whale watching, spear and lobster fishing, island picnics, snorkeling trips and even an overnight camping trip on a nearby island. One of the highlights of the trip!

making samosas

Making Samosas. Photo by JD Toppin

(for more adventures, check out JD’s travel blog here)

camping

Camping at Nosy Ve

We were assigned English partners and spent three sessions a week imparting our knowledge of the English language onto them with varying degrees of success. During the expedition my English lessons consisted of the pleasure and delight of trying to decipher then reinterpret the PADI divemaster manual for one of our boat drivers and dive master in training, Patty. Challenging? Yes. Poor Patty. I think I successfully confused him rather than enlightening him! If you’ve ever read a PADI manual, you may understand my struggle.

But back to my reason for travelling to Madagascar – the marine environment. I was here to count fish! As a volunteer, I had to learn 150 fish species along with 36 benthic and invertebrate species. Thank goodness our coral ID was limited to 11 hard coral formations and simply, soft coral. We didn’t have to be species specific. Those scientific names may have killed me! As it was, when I closed my eyes at night, I would see fish and corals flying at me and I’d be chanting names over and over in my head!

Luckily for me, I’ve been plaguing my brother with fish questions over the years of diving together, so I had a basic knowledge of some fish families before we even started, which was an advantage. But when it came down to species level, I still needed work, especially as not all the names were the same – moon wrasse became crescent wrasse, leather jackets became filefish, bullseyes – sweepers, flutemouth – trumpetfish…

Benthic on the other hand, was a bit of a struggle. I’ve never been overly enamored with benthic life, accepting kelp and sea grass, sponges, and corals as an important part of the ecosystem, but indifferent to their actual role and avoiding invertebrates such as sea cucumbers like the plague (ick!). However, our passionate field scientists were somehow able to convince me that benthic was cool and I subsequently looked forward to a bit of benthic surveying.

Goniopora

My fav coral species, Goniopora; despite it’s appearance, this is a hard coral! Image from Wikimedia Commons

I even overcame my fear of sea cucumbers one spring tide, when we helped the aquaculture farmers with their data collection. I opted to be the weigh-er, thinking it would be the best job to avoid handling any squishy, slimy, boneless creatures. Turned out, I had to pick up every. Single. One. Not once, but twice! After a few girly squeals, I managed to get into the swing of things. I can’t say I love them as a result, but I don’t have that fleeting moment of panic when I see them now.

seacucumbers

Zanga! (Seacucumbers)

The sites we dived ranged from healthy to pretty destroyed. The ones that didn’t look so great were affected by a combination of cyclone and storm damage plus destructive fishing practices and overfishing. Education and subsequent dinas (local laws) are in place, to outlaw destructive fishing methods such as poison fishing and beach seining. This has improved the health of the reefs in many areas, which is encouraging to see. Most sites were populated with small to medium reef fishes such as schools of snapper, fusilier, parrotfish and many species of wrasse. But the best part was diving in the protected areas and seeing HUGE fish, such as blue spined unicorns, often in schools, which seemed to be a sign that the protection zones were working! Win!

snapper

School of snapper. Photo by Niki Boyer

Diving with species knowledge really made it such a rewarding experience. It was always exciting identifying something you hadn’t seen in the water before, or something you struggled with! And I had some really special encounters including seeing a turtle – turtles are rare as they’re hunted as a coming of age ritual – hearing humpback whales sing quite regularly, a myriad of new nudis (colourful seaslugs), schooling, yes schooling Moorish idols, and even a sailfish!!

nudibranch

Some kind of Halgerda Nudibranch. Photo by Niki Boyer

Expedition life was an incredible existence for me. So far removed from my everyday reality in Australia. It was refreshing to be learning again and to be immersed in a culture and way of life I never knew existed. I will talk more about the people of Andava in my next post…

THINGS I MISS…

Being in or on the water every single day!

The infinite stars at night

Watching pirogues sail by

Constant sound of the ocean

The pace of life

The vazah and vezo friends I made

My hammock

Kids yelling ‘Salama’ everywhere you go

The dancing!

 

THINGS I DON’T MISS…

Sand in my bed

 

hammock day

View from my hammock

hammock sunset

Sunset from my hammock

stars

Stars! Photo by Ben Large

Initial Project Report

Slide1

Last week I presented at the University of Wollongong Post-Graduate Conference. I have adapted my presentation below as it was a good overview of my project to date. By way of some background, each year the biology post-graduate students are set a challenge to incorporate an object or personality into their presentations. This year it was Leonardo Dicaprio, so keep an eye out for some celebrity cameos.

So without further ado, let’s start this talk by having a quick think about why animals form groups. We might imagine that in a perfect world, the ideal way to ensure that you maximise your genetic contribution would be to breed as soon as possible and as many times as possible. This would involve leaving the natal territory as soon as possible to pursue individual breeding opportunities.

Slide2

So why then do we see so many examples in nature of reproductively mature animals which routinely delay or (in extreme cases) completely forgo their own reproductive opportunities in order to join and remain within a group as a subordinate non-breeding member?

The answer is that we don’t really know. We have a few ideas and theories about the costs and benefits of group living, but a general explanation has remained elusive. A major obstacle standing in the way of achieving a general explanation is that there are a lack of studies on marine organisms, which is what my study will focus on.

One of the most promising frameworks with which to study this behaviour is the cooperative breeding framework. This framework contains several hypotheses. I’ll go through just a few which I would like to test and which I will refer to throughout the presentation.

1) Ecological constraints – EC looks at a situation where ecological factors force animals into groups. eg. high predator abundance might cause animals to group in order to obtain a protective benefit through the dilution effect or by making use of discrete habitat patches which provide defence.

2) Life-history – LH hypothesis and EC are closely linked. LH hypothesis looks at inherent life-history traits of animals which might lead to a situation where group formation if more beneficial. For example, animals with long life-spans might cause a breeding habitat to become ‘saturated’. i.e. no vacant breeding ground for new recruits to make use of. In this case it might be more beneficial for the next generation of reproductively mature individuals to join a group and wait for the breeding habitat to become available (avoids conflict).

Most of these studies on birds, insects and mammals to date have either been broad phylogenetic comparisons or fine scale experimental manipulations. Both methods have merit and have in fact been responsible for the huge advances in this field, but there are few studies combining the two approaches. It is important to combine these methods as the broad scale studies can draw correlative conclusions across multiple taxa, but they don’t offer causative explanations. Which is where the experimentation becomes important. However, fine scale experimentation can only focus on a few taxa so the results are often difficult to apply generally across multiple taxa.

So how am I going to approach this question?

I will use a genus of coral reef fishes which show considerable variation in social organisation as a model. Gobiodon species are found in high abundance on tropical reefs. There are over 20 known species.

Slide3

I will start by conducting a broad phylogenetic comparison of the Lizard island population of Gobiodon. This will involve making a genetic phylogeny of the species at Lizard Island (the above picture shows the phylogeny of the Red Sea population). Phylogenies show how closely related species are to each other. Species radiating from a common node are more closely related to each other, than to species originating from other nodes. The nodes represent some common ancestor. Looking at where sociality occurs on this phylogeny is important as we can see whether the behaviour arose at a single evolutionary point or whether it has evolved multiple times. Looking at the tree above, social behaviour does appear to have evolved multiple times.

Using this phylogeny as a base, I can map ecological and life history traits of each species. This will show which traits the social species share and which the asocial species have in common with each other. I will use this information to identify traits to manipulate experimentally to try to induce social behaviour in an asocial species or vice-versa.

I have chosen these fishes because they show great variation in social structure. for example G. histrio is stubbornly pair forming like Romeo and Juliet. While G. rivulatus forms large social groups more akin to the Great Gatsby, although I suspect that there might be some reproductive shares going to subordinate individuals in the Great Gatsby…

Slide4

But back to Gobiodon; they are also highly site attached, which makes observing and cataloguing their social systems, ecological traits and life history traits far simpler and experimenting logistically easier with them. Once they have chosen a coral to settle in, that is where they stay. Even when the water level drops below their corals during extreme low tides, they will hunker down and remain within the coral, exposed to air for a couple of hours. They have a high hypoxia tolerance and air breathing ability which enables them to do this.

Slide5.1

I have chosen Lizard Island in far north queensland as my study site because:

Slide5.2

Click to enlarge

a) it has an exclusive resort where celebs like leo can be found. Unfortunately, they don’t let the researchers stay here. They tuck us around the corner in this photo.

 

 

 

Slide5.3

Click to enlarge

b) most of the species of gobiodon are known to occur here (and possibly a new species). It’s also worth noting the size of these fishes in the picture below. The fish in the second and fourth pictures on the top row are actually sitting on my gloved hand.

 

 

Slide5.4

Click to enlarge

c) There is a well established research station here run by the Australian Museum which makes field work and experiments much easier.

 

 

We started this work by finding Gobiodon colonies around lizard island and capturing, counting and identifying the species. To capture the fish we use a mixture of clove oil and ethanol which anesthetises the fish and then we ‘waft’ them out of the coral. Once we capture the fish we hold them in plastic bags until the end of the dive and then take them to a boat to be processed.

Slide7

To build the genetic phylogeny we need to obtain genetic material. I’ve been taking fin clips from the fish for this. We just snip off about 1/8th of the caudal (tail) fin area while the fish are anesthetised. It’s not uncommon to see these fish with much larger chunks taken out of their fins, usually from conspecific disputes. The fins do grow back quickly so we’re not doing any permanent damage to the fish.

While we have the fish on board and anesthetised, we measure their SL and TL and we give them little tattoos. These are a flourescent elastomer tag inserted under the skin so that we can identify the fish again when we come back in order to determine some life-history traits like dominant turn over rates or growth rates or mortality.

To collect the information about the ecological traits to map onto my phylogeny, I have been seeking out Gobiodon colonies and taking Coral measurements.

Slide8

To measure habitat saturation we have been using x-transects centred on a colony of Gobiodon. We move along each axis of the transect and catalogue all of the corals known to be inhabited by Gobiodon species. We record whether they were inhabited or not, what they were inhabited by, how many individuals are in each coral, the size and species of each coral.

This gives us an indication of how many and what types of colonies are surrounding the focal colony and how much available habitat there is in the immediate area.

I need to complete the phylogeny now to map these LH and ecological traits and see if there is any correlation between sociality and these traits.

Slide9.1

The downside to working in beautiful tropical locations is that they are prone to cyclone activity.

Cyclone Ita came right over Lizard Island in April this year. The photos below are taken from the same sites (left to right) before and after the cyclone. In February, my assistants, and I had tagged about 600 individual fish with a plan to come back in 6 months to re-capture and re-measure these individuals and determine growth rates and dominant turn over rates. I returned in August and found 8 of the original 600 tagged fish.

Slide9.2

But moving on, I am still interested in the evolution of social behaviour in these fish, but I will focus more on the evolutionary advantages of sociality or asociality in re-colonising a reef after a disturbance. And I’m hoping that I’ll be able to see that recovery in the data coming out of the x-transects that we’re using to measure habitat saturation.

Anecdotally, there appeared to be more uninhabited corals than there were in February, though I can’t verify this statistically because I used different methods (we were looking at a different question in February). There also appeared to be more juveniles present in August than in February.

Slide10

Moving on to some preliminary results, these tables show the results from a statistical method called a Generalized Linear Model or GLM for short. Don’t worry about that or all of the technical looking numbers, all you need to know is that a significant result is indicated in red or a highly significant result in yellow. For most of the species above, there is a significant result for average diameter of the coral. That just means that there was a strong relationship between the size of the coral (the predictor) and the number of individuals living within the coral (the response). i.e. the size of the coral could be used to predict the number of fish living within it for those species with a significant result.

I’ve found that the group size of some of the social Gobiodon species is related to the coral size, but not to the size of the largest individual (alpha), which is interesting as Marian Wong and Pete Buston (who presented at UoW a couple of weeks ago) had found that there was a relationship between both coral size and the size of the alpha with the group size in the anemone fish Amphiprion percula. G. oculolineatus does appear to follow this pattern. What I can take away from this is that the determinant of group size is probably species specific and will therefore be more difficult for me to make general conclusions about.

Looking at some of the before-after cyclone data that was comparable, the corals that did survive the cyclone showed positive growth. However when we looked at the site as a whole, the average size of the corals had decreased. This was to be expected since, as you can imagine, a major disturbance like a cyclone would smash up the larger corals into smaller corals. The smaller corals also have less surface area so are more likely to survive a cyclone.

Slide11

I’ve also found that, as you would expect there was a decline in the coral goby abundance. However, the second graph is more interesting. Some species, like G. erythrospilus, G. rivulatus and G. unicolor appear to be occurring in larger groups post-cyclone. This is possibly an indication that they are in a phase of recruitment.

Slide12

This will require further exploration so I have another trip planned for January. During this trip I will be re-conducting the x-transects in order to examine this trend across multiple sites. What I will be looking for is whether there is a detectable shift in the goby community. There might be a higher proportion of social species present which could indicate that social species have some kind of advantage in recolonising a reef after a disturbance (or vice-versa).

Slide13

I will now need to finish the genetic phylogeny and map on the ecological traits that I have collected so far. I have another round of field work booked in for January. I will be conducting more of the cross transects to see if there has been a detectable community shift since my last visit. I also want to set up a pilot experiment looking at the effects of habitat quality and habitat saturation on a subordinate individual’s decision to move or not.

I would also like to set up and run the life history traits work again. i.e. the capturing and tagging component, as this is a really important part of the cooperative breeding framework which I’d like to explore.

To finish up I’d like to say a final thank you to my assistants for their help in the field. It really is a big commitment for them to come and help me out for weeks at a time. Thank you very much! My work could not happen without your help.

Slide14

If anyone has any questions about my project, please leave a comment below. Thank you!

A MADAGASCAN ADVENTURE: Part 1

Part 1: Discovering Madagascar

When my older brother, asked me to write a guest blog I was at first excited and then terribly daunted. I should preface this post with the fact that I am not a scientist, so the following is purely based on the observations of an amateur!

I have been diving since 2005 and have a passion for all things ocean. I also love to travel. After spending the past 6 years behind a desk, I decided to temporarily abandon my Sydney life to spend some time indulging in some underwater delights and a slower pace of life.

So, I’ve recently returned to Australia after months of diving and travelling, including three months living in a remote fishing village, Andavadoake, on the south west coast of Madagascar. I was volunteering with a UK based marine conservation organization, Blue Ventures, who have been working in the area for over 10 years.

01 Madagascar-map-02

I have wanted to visit Madagascar for many years after seeing an image of the Allée des Baobab in a travel magazine as a teenager. And who doesn’t want to see lemurs in the wild?! However, it was with naivety that I embarked upon this adventure knowing very little about the country and its people, not to mention the extensive reef system – one of the largest in the world! All I knew was that I would be diving everyday (win), and would learn some science to help monitor the local reefs (win)… AND I would be there during whale season (WIN).

Humpbacks passing by. Photo by Sam Blyth

Humpbacks passing by. Photo by Sam Blyth

What I quickly learned was that Madagascar is not a country filled with primordial rainforest and troops of lemur bouncing around, but a country of varying climate and terrains. I drove through endless rice paddies and farmland reminiscent of my travels in South East Asia; vast rocky scapes that hold minerals and precious gems; the desert spiny forests full of the famous octopus tree; and finally, the turquoise, sparkling ocean. It was surprising and sad at times, knowing that much of this land, in fact, used to be primordial rainforest, but that’s perhaps, a discussion for another time.

Farmland in central Madagascar

Farmland in central Madagascar

Rocky scapes

Rocky scapes

Turquoise waters of Salary

Turquoise waters of Salary

I arrived in Andava with my fellow volunteers right on sunset, having travelled four days overland. We were a little disheveled yet full of excitement from our first experiences in Madagascar, which involved descending from the central plateau by hazard lights as our headlights didn’t work; a crazy Chinese hotel where we struggled to find our rooms in the labyrinth of corridors; lemur, chameleon and scorpion sightings; a flat tyre; hiking desert canyons; swimming in freezing pools in small oasis’; our first taste of Malagasy rum and dancing; incredibly rough ‘paved’ and unpaved roads; and more lemurs!

Hiking the canyons of Isalo

Hiking the desert canyons of Isalo

But finally, we were standing on the beach and gazing at the sun as it dipped into the ocean for our first (of many) Andava sunset. I rarely missed a sunset after that, as my thousands of photos suggest. This would become one of my favourite parts of the day.

First sunset in Andavadoake

First sunset in Andavadoake

In my next post, I will delve into my time as a volunteer diver in the village of Andavadoake…

GobyPro issue 2

Welcome to the second edition of Gobypro!

It’s been quite a while since the previous post of GobyPro and we’ve been out in the field collecting more photos.

As promised in the last issue of GobyPro, Oranges are up first. We called these guys ‘Oranges’ because their species name is citrinus, which kind of sounds like citrus. G. citrinus is found mostly in big bunches of staghorn corals like A. intermedia. We usually saw them in large groups with two dominant breeders. These are the giants of the Gobiodon world, reaching sizes of up to 6.5 cm! Despite their massive size they were extremely difficult to capture as they would retreat right down into the coral. I really want to capture a few groups of these ones to see if they have a distinct size based hierarchy, but no luck so far. While I was diving in Indonesia recently, we found a group of G. citrinus which were black in colour.

G. citrinus

G. citrinus

G. citrinus black variant

G. citrinus black variant

Next we have the lemons, G. okinawae. These gobies are a very distinct bright yellow – hence the nickname “lemons”. We also called them lemons because we often found them living with a G. citrinus colony, forming a pretty little underwater orchid. Unlike most other species of Gobiodon, the lemons are the only species in this genus which like to hang out at the branch tips of the corals and often hover above and even move between corals. We found individuals ranging from 1.0 cm to 3.5 cm.

G. okinawae

G. okinawae

Goby Trivia

Some species have a high hypoxia tolerance and air breathing ability, meaning that they can stay in their corals even if the coral becomes exposed at extreme low tides.

Nilsson et al. 2004. Coward or braveheart: extreme habitat fidelity through hypoxia tolerance in a coral-dwelling goby

We saw this incredible ability on the last field trip during a king tide.

A G. erythrospilus, high and dry

A G. erythrospilus, high and dry

In the next issue of GobyPro:

An unidentified species of goby that we found on our last field trip.

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I won a competition!

Woohoo! Just thought I’d share this great news. I don’t win things very often, usually because I don’t enter, but this time I thought I’d throw my hat in the ring and now I’m the proud owner of a copy of Aaron Wong’s new photobook, “The Blue Within”. I din’t win the big prize of a free trip on board one of the Siren fleet boats, but my photo took out the month of May competition. I’m pretty chuffed 🙂

49842005

Back in May this year, my partner and I went on a live-aboard dive trip in Indonesia on board the SY Indo Siren. On board I saw that they were accepting photographs for a competition. I only have a GoPro, which I’ll admit doesn’t generally take award winning photographs. I’ll also admit that I am a complete hack when it comes to any sort of photography. I know the photos I like and dislike, but otherwise words like “composition”, “F-stop”, “aperture” and “focal length” are pretty lost on me.

But, I liked this photo. So I submitted it and apparently the lovely folks at Worldwide Dive and Sail also liked it. Thanks guys!

Lizard Log 26/8/14 – 30/8/14

Day 25 26/8/2014

The wind had dropped slightly this morning so we braved the lagoon again. We went to a site on the edge of the Palfrey reef system which I hadn’t been to before. The coral there looked to be in quite good condition. It would be worth doing some more transects along there. It was a bit surgy underwater, but the reef gets a bit of protection from the Bird Island reef. As we were swimming back to the boat, after completing our transects, we found a huge plate coral with a big school of sweet lip under it. They were pretty curious and came right up to Kylie for a photo.

Sweet lip hanging out under a plate coral.

Sweet lip hanging out under a plate coral.

We did our second dive on another section of the same reef. We decided to try this section because we were on a falling tide and the reef edge was deeper than the first site. Unfortunately the reef edge had none of the corals we needed, so we went up onto the reef flat. It was nice and protected in behind the big Porites bommies which made up the reef edge. We found a few G. brochus colonies up there which was good as I haven’t been able to do too many transects on them yet. It just takes me forever to find the little buggers as they bury themselves deep in A. loripes heads, which are really dense.

As we were heading back to the boat, we found several artificial reefs out on the sand. One of them had a plastic cage over it. It looked like an abandoned caging experiment. We took a couple of photos and then headed to the boat. We told the director about them and found out that it was a really old experiment, long since finished. They will be removed soon. It’s a bit of a shame as they now have quite a bit of growth on them. But it is a good reminder that we need to remove all of our equipment from the field when we’ve finished. Especially when working in a World Heritage area.

Old experiment left in the field.

Old experiment left in the field.

This afternoon we said farewell to the two Australian Museum researchers who had been our lab buddies for the last five days. They were good fun to share a lab with.

Day 26 27/8/14

Today we went back to the same reef system we’d visited yesterday. The wind had picked up again, but it was still quite manageable underwater. We got some great data over our two dives. The only downside was that the battery on the GoPro ran out so we couldn’t take photos of the corals on our second dive. It’s not essential, but it helps with coral identification and I’m planning on revisiting all the photos to make a visual complexity estimate of the corals.

We found a couple of beautiful big Nembrotha nudibranchs (I think) on our first dive.

Nudibranchs

Nudibranchs

Day 27 28/8/14

Kylie and I headed out to Palfrey again today. One of the Bshari lab group students came out with us today. She was documenting wrasse interactions with cleaners. She snorkelled around the boat, following fish, while Kylie and I went about our business. Luckily, she is Swiss, so she didn’t get cold on the surface while Kylie and I froze on our two 90 minute dives. Acclimatisation is a …. not very nice thing….

Kylie spotted an octopus watching us from a hole in a coral head on our second dive. After we’d completed the transect near our friendly cephalopod, we swam off to find a new transect site. When we found a good spot, Kylie swam back to collect the transect and bring it to our new site. She swam past the octopus’ hidey hole, but it wasn’t there anymore. When she got to the transect, the octopus was there checking it all out, running its tentacles over the PVC tubing and tape measures. When it saw Kylie it ducked into a hole, but kept one tentacle on the transect. They’re such inquisitive animals!

Curious cephalopod

Curious cephalopod

Kylie and I were both feeling quite tired in the evening so we decided to have an early dinner and get an early night. I love socialising here with the housemates, but it was so nice to lay down and turn my brain off early.

Day 28 29/8/14

Kylie and I had a bit of a later start today because our resident baker, had made bacon and cheese rolls for breakfast. Delicious! I’ve said it before and I’ll say it again; Awesome housemate!

The wind was blowing hard today. We had a pretty rough boat ride out to our site today. Kylie and I were both feeling pretty knackered today so we decided to just do a single dive at Trawler Beach. Under the water, the conditions were quite manageable and we got four transects completed.

Kylie being useful

Kylie being useful

Bumpy boat ride

Bumpy boat ride

This afternoon I got stuck into organising my data. It’s a big job so it’s good to get a head start on it before I get back from the field. I also took the opportunity to catch up on the emails that have been building up and filling in some of the collection forms for the various permits and databases I’m a party to.

Day 29 30/8/14

Kylie and I got back out to Trawler today for our dives. The wind was still blowing hard on the surface, but underwater was fine. It felt cold though! I’m going to have to resort to zipping up my wetsuit I think.

We decided to pick our way through the patch reefs and head to Trawler Beach for our surface interval. We took shelter at the eastern end of the beach, near the mangroves. The water was beautiful and still there and it was reasonably out of the wind. It was still a bit cold though as it was a pretty overcast day. I know we’re supposedly in the tropics, but it is cold in a wet wetsuit with a 30 kt wind.

Trawler Beach

Trawler Beach

As I was donning my dive gear in the water for the second dive, a big green turtle came up from the reef to see what was happening. It circled me and then casually swam off when Kylie turned up with a camera. It had two great big remoras accompanying it. One of the remoras was bigger than the poor turtle’s shell!

It was BBQ night again tonight. The decision was made to hold the BBQ in the beach house because of the wind. Although the wind had dropped by the time we went down to the beach for sunset drinks and it was actually quite pleasant. It’s more intimate in the beach house though and you can talk to more people so it was fine.

Sunset

Sunset