Marine biodiversity in Oman: Mini-blog 2 – Meet the team

In the previous blog I wrote how I joined a great team of researchers to study fish diversity in Oman. The scientists I’m working with are experts in their fields, and form a very complimentary group, perfect to be studying fish diversity with. It’s fantastic to be collaborating with them, especially since this kind of work is new to me, which means I am learning loads at the moment! So it’s only fair to introduce the people that are really driving this trip.

Amanda

Ms. Amanda Hay: Amanda is Acting Ichthyology Collection Manager at the Australian Museum. She is a taxonomy expert, specialised in larval fishes. While she considers herself a jack-of-all-trades, she is the most organised member of the team who makes sure all the fish are named and catalogued properly.

 

Chris

Dr. Chris Goatley: Chris is a postdoctoral research fellow at University of New England who specialises in reef fish ecology. In particular, Chris is interested in the ecology of the smallest coral reef fishes, including gobies and blennies. He is particularly interested in the roles of these small fishes in maintaining coral reef food webs.

 

DarrenDr. Darren Coker:  Darren is a Research Scientist in the Red Sea Research Center and Saudi Aramco-KAUST center for Marine Environmental Observations at King Abdullah University of Science and Technology in Saudi Arabia. Here he focuses on reef fish communities along environmental gradients and how local and global stresses influence fish groups that are important to reef health.

Alyssa MarshellDr. Alyssa Marshell: Alyssa is an Assistant Professor in the College of Agricultural and Marine Sciences at Sultan Qaboos University. She is on of the lead investigators on the DFAT CAAR grant that funds this research project. Alyssa is an expert in marine and spatial ecology, with particular interests in the movement and behaviour of herbivorous reef fishes.

JoeyDr. Joey DiBattista: Joey is the new Curator of Ichthyology at the Australian Museum and standing member of the TrEnD Lab at Curtin University. Joey is the other lead investigator on this research project. His name might sound familiar if you follow this blog, since he has written a very interesting guest blog in the past. Joey is interested in developing next generation-sequencing tools to aid in  fisheries management. His new position role at the museum will allow him to build up genetic “barcode” libraries for fishes across Australia.

These are not the only team members working on this project, other researchers involved include remote marine field specialist Tane Sinclair-Taylor, PhD student Mark Priest, and Director of the Red Sea Research Center at KAUST – Professor Michael Berumen. Their contribution is at least as important as the other members, but they are unfortunately not close enough at the moment to hassle them for info.

Lastly, the newest, honorary member of the team is our Musandam captain Ali! Ali owns  Ras Mudandam Diver, the dive centre that was taking us out for our work here. He’s been an absolute legend, and if you’re considering diving here, you should definitely look him up!

Ali

Captain Ali

 

 

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Does climate change create damsels in distress? – Guestblog by Tanika Shalders

TanikaThe latest guestblog on Critter Research is by Tanika Shalders. Tanika is a Technical Officer for the Marine Science Program at the Department of Biodiversity, Conservation, and Attractions in Australia. Her current work entails diving on some of the most amazing reefs in Australia and video analyses of surveys in Australian marine parks. In this guestblog she describes her recently published research on the effects of climate change on damselfishes.


It is currently spring in Australia, a lovely time to be outdoors. Nice temperatures (average maximum of 22), plants in full bloom, perfect picnic weather… just find a nice patch of grass, a cold beverage and some snacks.

Heatwave dogSummer is just around the corner and here in Perth it can get very warm, with an average maximum of 31 degrees (although temperatures up to 40 degrees are not unheard of). Unfortunately, picnics are not as pleasant this time of year. It’s hard to find shade, you’ll likely get sunburnt and your drinks will get warm.

What do you do when the temperatures become unbearable? Head to the coast to cool off in the ocean? Hide in the air-conditioning? Increase your ice-cream consumption? We try to make ourselves as comfortable as possible, moving to a cooler environment where we have everything we need – food, water and shelter.

With this in mind, it is no surprise to learn that other animals are doing exactly the same thing when ocean temperatures rise. Over the past 5 decades ocean temperatures have been increasing due to climate change. There has also been an increase in heat waves.

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Heat waves are becoming increasingly common across the world

Many people connect these events to coral reefs, so it may come to some surprise that the ocean in temperate (southern/cool-water) Australia is warming at least twice as fast than the global average.

In 2011, the south-west of Australia experienced a heat wave. The heat wave lasted more than 10 weeks and temperatures increased up to 5 degrees above normal. This event caused massive changes to the marine environment of south-west Australia. One of the most significant documented impacts was the loss of kelp along the south-west coast. In the warmest area (north) kelp disappeared completely. Changes have also been seen in other organisms such as fish and crustaceans.

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Ecklonia radiata, the kelp species which was greatly affected by the 2011 heatwave. Source: foragersyear.wordpress.com

After the heat wave, we decided to investigate if fish had also been impacted by the extreme temperatures. We chose to look at territorial damselfish since they are ‘site attached’. Much like the Hobbits of Middle Earth, they don’t like to leave home. These damselfish farm and protect algae which they use for food and reproduction. This trait makes them a good species to indicate of change as it is unlikely individual fish will move from their home to a new location. However, juvenile fish (recruits) may set up camp in new locations.

Using diver operated stereo-video (DOV), we investigated where these damselfish lived before and after the 2011 heat wave, and how many there were.

Damselfishes

The damselfishes in this study. A) Parma occidentalis; B) Pomacentrus milleri; C) Parma mccullochi; D) Parma victoriae. Sources: Fishbase and Reef Life Survey

The main result was that the two (northern) warm-water damselfish became more common in the (southern) cooler waters. The two cooler-water damselfish showed less change.

We also saw a change in algae habitat. The kelp that dominated in 2006 had often been replaced by smaller forms of algae by 2015. This included the turfing algae such as those farmed by the damselfish.

So what does this mean?

These results show that both fish and their habitat are changing due to climate change. When warm water fish move to cooler water, they might push out the local cool water fish on their way south.

This process of warm water fish moving into cooler environments is known to the science world as tropicalisation – previously explained in a guest blog by the wonderful Dr Joseph DiBattista so I won’t go into detail here. Instead I will delve into one of the flow-on effects of tropicalisation: increased competition.

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Tanika collecting Diver Operated stereo-Video (DOV) footage. Photo: Will Robbins, DBCA

Competition happens everywhere in the natural world. Plants compete for sunlight, lions compete for antelopes, and high school boys compete for the same girl. Usually competition occurs over food, water, shelter, or booty. Any additional players entering such a highly competitive environment can have devastating effects.

The movement of warm water fish into cooler waters could increase competition for the local fish populations. Since these damsels eat the same food and are very territorial, this means they not only have to compete with each other, but also with new damsel species. It’s hard enough to compete with your siblings for the last helping of dinner – imagine having to compete with your whole street!

Often this means that the local species will have retreat from an area once the invading species starts competing with them for food. Fortunately in this case, it looks like the change in habitat meant there was more food for the damselfish. It is likely that this helped to support a larger number of damselfish by reducing competition.

Most people are starting to become aware that climate change is an issue, sadly it’s a much bigger problem than most believe. Scientists are just being to scratch the surface of understanding the full reach of its impacts. If you would like to learn more about climate change and what you can do to help, please visit this site to find out more.

 

Tanika Shalders

Technical Officer, Marine Science Program

Department of Biodiversity, Conservation and Attractions

Twitter: @TanikaCShalders

Instagram: tanikacs

Research Gate: Tanika Shalders

DOV 1

Climate change might increase competition in the oceans. Photo Will Robbins, DBCA

Finding the Knysna Seahorse: Mini-blog 5

It’s already been a week since I arrived in South Africa to study the endangered Knysna seahorse with Dr. Louw Claassens from the Knysna Basin Project. Together we are testing if environmental DNA (eDNA) can be used to find rare seahorses and pipefishes.

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eDNA filtering in progress

To do this, we have been travelling along the southern coast of South Africa, taking water samples along the way in estuaries where our focal species lives, where it used to live, or where it might live. Yesterday we left Knysna to sample water in Klein Brak and Groot Brak. We are especially interested in the Klein Brak estuary, since there are multiple anecdotes that the Knysna seahorse (Hippocampus capensis) used to live here. Nobody has checked recently if it really was the Knysna seahorses and it seems that the most recent sighting has been many years ago. Because of this, it is usually assumed that there are no more Knysna seahorses in Klein Brak.

This brings me to a very important (maybe the most important?) question about this whole endeavour: WHY are we actually doing this? It’s all good an well to say that we want to help these endangered animals, but what exactly are we hoping to achieve? What will our results mean for managing the endangered Knysna seahorse, the critically endangered Estuarine pipefish, or any other endangered small fish for that matter?

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Knysna estuary, just imagine all the seahorses down there!

What we are hoping to achieve can be summarised in three main points.

  1. We want to test if the eDNA method can really be used to find small, endangered fishes (particularly seahorses and their relatives). So far, previous research has shown that eDNA work on large fishes such as sawfish, but it is not sure yet if this will work for seahorses, which are obviously much smaller.
  2. The best case scenario would be that we could also find seahorses in estuaries where it was thought to have disappeared. This would be great news for the conservation status for the species, as it would mean that it occurs in a wider area than we thought, which would mean that it is less likely to go extinct.
  3. If this would happen, it would mean two things. First of all, the new locations would have to be studied, so we can find out how many live in these estuaries. It would also mean that those new places need extra protection and monitoring to ensure the species do not disappear from their newly discovered homes.

Ultimately, if the eDNA method works for small, endangered seahorses (or their relatives), it could be used to monitor small fishes worldwide. This would help solving one of the biggest problems with studying small species, especially those that are rare or hard to find.

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Louw looking for Knysna seahorses in the Thesen Island Marina (she found 3!)

Finding the Knysna Seahorse: Mini-blog 2

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Sunrise in Kariega

Today was the first day of collecting samples in South Africa and the first sampling location was the Kariega estuary, near Kenton-On-Sea. We were joined by two researcher from SAIAB (South African Institute for Aquatic Biodiversity), who study a relative of the Knysna seahorse: the estuarine pipefish (Syngnathus watermeyeri). A species which is critically endangered, it is in fact so rare, that it was thought to be extinct in the early nineties until it was re-sighted in 1995. Since we are collecting environmental DNA (eDNA) samples in this area, we decided to temporarily team up with Paul and Nikki to see if this rare species can be detected with eDNA.

But what exactly is eDNA, or more precisely, how does it work?

The basis of this method is that all living beings contain DNA in their cells, and that all living beings “shed” this DNA in their environment. On land this can for example be through hair or feces, for fish this can happen through mucus, excrement, scales, etc.  These tiny bits of DNA then float in the environment (the water in our case), which brings us to the actual sampling.

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Kariega estuary, full of tiny bits of environmental DNA

Collecting eDNA is pretty simple, we just scoop up water. That’s it. Really. But the actual work begins after the water is collected. The first step is to filter the water using a very fine filter which (hopefully) traps all the DNA in the water. At this point there is a LOT of DNA on the filter paper, most of which will be from bacteria, or larger species you may or may not be interested in.

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Filtering water, exciting stuff!

The tricky next step (which will be done in the TrEnD laboratory at Curtin University), is to find the DNA you are looking for, which is very much like searching for a needle in a haystack. But both the hay and the needle are so small you can’t actually see it with a microscope. Scientists much smarter than me found a very clever solution to this: they invented a kind of magnet that basically pulls out the needle.

This magnet is called a “primer” and is based on how the DNA of different species (or families, or genera) is different from each other. These differences make it possible for geneticists to develop primers (=magnets) that can detect different things. Some primers are used to detect multiple species, for example: there are primers that will detect (almost) all bony fishes, others could be used to detect sharks. Other primers are more specific, like in our case, where we try to detect only 1 species. Alternatively, another project at Curtin University is currently working on a true “seahorse-magnet”: a primer that will detect all seahorse DNA in the water, regardless which species of seahorse.

As you can imagine, eDNA is a very exciting method with lots of potential uses. It is also a relatively new method, so lots of finer details still need to be studied to make the most of this technique.