Saturday, March 24, 2018

An Interview with the “Sherlock Holmes” of Sawfish



Many of you may be familiar with Matt McDavitt’s fascinating posts on the Sawfish Conservation Society’s Facebook page, while others may know him as the source of knowledge on the cultural role of sawfishes around the globe and the owner of a renowned sawfish rostra collection that is used for research. Either way, if you ever have the chance to talk with Matt, you will understand why some call him the “Sherlock Holmes” of sawfish. At SCS we wanted to find out what started Matt’s drive for sawfish knowledge and what he finds so interesting about our toothy friends.  

What career field are you in? 
            
          I am a research attorney; basically, I develop legal arguments and I ghost-write for other lawyers nationally (and occasionally internationally), usually regarding probate and trust litigation, as well as environmental law, and admiralty/shipping law.

                                            
                  PC: Matt McDavitt, This is Matt standing next to a large Green Sawfish rostrum.



           How/when did you first become interested in sawfishes? 
      
    I’ve always had a strong interest in sharks ever since early childhood, but my specific fascination with sawfish arose in early adulthood. During my first semester of college I took a course on comparative religions; as part of the class, we studied Aztec religious beliefs and practices. While researching a paper for that unit, I examined copies of the surviving Aztec painted books, and located several symbols that looked to me suspiciously like sawfish saws. I poured through the literature interpreting these beautiful screenfold almanacs, but none of the authors identified the strange spiky objects I’d noticed; apparently no one knew what those objects were!  I was hooked – I spent the next four years learning about Aztec language and culture, trying to find out if they knew of sawfishes and used their saws for some purpose. What I found was that sawfishes were symbols of the earth deity in Aztec thought, specifically linked to warfare, because they, like warriors, carried swords. When the main temple of the Aztecs was excavated in Mexico City, the archaeologists found dozens of sawfish saws in the many offertory caches buried beneath the structure.

                                                          
                        PC: Matt McDavitt, An example of an Aztec depiction of a sawfish rostrum.



Do you have a favorite sawfish species? Why?


    Probably the Dwarf Sawfish, Pristis clavata – they are still quite mysterious in many ways, and I love their unique glowing, grey-gold color.  Traditionally, we’ve thought Dwarf Sawfish to be confined to the coasts of northern Australia. However, museum specimens reveal that this species formerly occurred in Indonesia, with a range up to at least the northeast coast of India. I’ve found dwarf sawfish saws deposited in Thai temples, strongly suggesting local occurrence in Thailand, and I located naturalist drawings and descriptions from Myanmar apparently depicting this species. I wonder why Dwarf Sawfish and Green Sawfish differ so much in their saw morphology, with the Dwarf Sawfish’s saw proportionally extremely short (as little as 1/5 of the total length), versus the Green Sawfish’s rostrum, which makes up a much larger percentage of the animal’s length (up to 1/3 of the total). Certainly, this disparity between short-sawed Dwarf Sawfish, compared to the lengthy saws borne by Greens reflects some morphological adaptation either to their respective environments or behavior!  Hopefully, we can answer such questions in the future.

    What was the first rostrum in your collection? How did you come across it?
     
    The first rostrum I acquired was a large, old soot-blackened Smalltooth Sawfish saw that I came across in an antique shop near my college over two decades ago.  It was hanging on a wall of archaic tools and was labeled as a “farming implement”!


PC: Annmarie Fearing, These are a few of the sawfish rostra from the McDavitt Collection.



If you are willing to share your secrets, how do you find all the obscure sawfish information/photos you post on the SCS page? 
      
    I have a “secret weapon” regarding how I locate sawfish material on the internet, but that will have to wait for another day, so that my methodology is not compromised!

What is the most interesting listing you have come across online for sawfish rostra/fins/etc.?
    
    I guess that would be the listings I find from the Chinese folk religion practitioners throughout South East Asia. They believe that sawfishes are the children of the Sea Goddess, and thus supernaturally powerful; they believe that the saws of any animals accidentally caught must be deposited at a nearby temple to assuage the dangerous spirit of the sawfish (they also believe that sturgeons are the sole physical form assumed by dragons!).  Practitioners of this religion use sawfish saws essentially as magical swords, with the supernatural power to dispel the hungry ghosts and demons that plague mankind with sickness, misfortune, injurious accidents, and death.  I’ve found similar beliefs from East Africa all the way to coastal China!

Have you ever seen a sawfish in the wild? If so, where were you and when? If not, where would you like to travel in hopes of seeing a sawfish?
    
    Although I spent a summer on Lake Nicaragua specifically looking for sharks and sawfish, and I once accompanied Colin Simpfendorfer and Tonya Wiley-Lescher on one of their sawfish tagging excursions in southern Florida, I have not yet seen a sawfish in the wild. 

In cultures where multiple sawfish species are present, are the sawfishes as a group culturally important or do different species have different meanings in these cultures?
     
    From what I’ve found, societies generally make no distinction between sawfish species based on body-form or behavior (i.e., marine versus freshwater animals).


PC: Annmarie Fearing, A painted rostrum from the McDavitt Collection



How many different languages can you say “sawfish” in?
     
    Probably hundreds; I have recorded terms for sawfish in over 50 Australian Aboriginal languages alone!  Such terms can be useful to determine historical distribution of animal species; in a new project I am working on, I’ve located multiple sawfish place-names in indigenous languages in Australia and in Mexico/Guatemala/Ecuador, likely marking areas where sawfishes were formerly abundant. 

In your opinion, what culture has the most interesting representation/view of sawfishes and can you tell us a little about it?
     
    There are many beautiful sawfish symbols and metaphors all over the coastal tropics. One of my favorites comes from several Kongo-speaking cultures along the coasts of east central Africa. African societies often traditionally transmitted important values, morals, and observations on human nature via proverbs.  Certain proverbs were also represented in art, to visually convey the lesson they contained. To these Kongo peoples, who had witnessed sawfishes in bays, estuaries, and rivers slashing at fishes, the sawfish’s fondness for striking at the fish that swam within range of its toothy saw was a natural symbol for judicial impartiality.  The proverb translates: “The Sawfish Saw: all fish that went in front, I cut the same!”, conveying the message that justice, must like the sawfish’s hunting technique, be applied impartially, so that one’s status or rank should never affect the outcome of a judicial matter.  It is equivalent to the Western world’s “Lady Justice” symbolism, which also states that justice must be blind and applied equally to all.  Thus, traditionally, a stylized sawfish saw was the symbol of fairness under law, which I think is a beautiful and important concept to be linked with the remarkable sawfish. Perhaps sawfish populations would be in better shape globally if they possessed similar symbolic value in other cultures…


PC: Annmarie Fearing, A painted Narrow Sawfish rostrum from the McDavitt Collection


Monday, October 16, 2017

Behind the Scenes of International Sawfish Day

Annmarie Fearing    



Katy Duke
Image credit: The Deep
   The Sawfish Conservation Society had the pleasure of interviewing Katy Duke, the Chief Executive Officer of The Deep aquarium in Hull, England. After working in the aquarium industry for over 22 years, she has become captivated by sawfish and has taken on the additional role of European studbook keeper for sawfish. As the studbook keeper, Duke is in charge of compiling and maintaining collective histories of captive sawfish in Europe for population management purposes. 

   She is currently working with other aquariums and researchers around the globe to further sawfish conservation. As someone who helped get International Sawfish Day (ISD) off the ground, we wanted to hear Duke’s thoughts on what ISD is all about.

    According to Duke, the initial idea for ISD came during the American Elasmobranch Society Sawfish Symposium in 2016. Duke, Paula Carlson (Dallas World Aquarium), Stacia White (Ripley’s Aquarium), Alan Henningsen (National Aquarium Baltimore) and Nick Dulvy (IUCN Shark Specialist Group Chair) were discussing how great it would be to have a day for everyone around the world to celebrate sawfish. “We realized there was enough enthusiasm at the symposium so we decided to go for it, and International Sawfish Day was born!”


 
Green sawfish (Pristis zijsron) swimming at The Deep.
Photo credit: The Deep
   With an international day, such as this, there is always a driving goal behind it. “Right now, the goal of ISD is to promote awareness of sawfish. We want to create a buzz  and educate the public on what sawfish are and why they are important,” says Duke. Sawfish are considered the most threatened of all sharks and rays, yet their plight is not well known by the public. Sawfish have suffered a large decline in both range and abundance from accidental captures in fisheries, exploitation for their fins and saws, and from loss and degradation of habitat. With a ‘tooth’-lined saw making up to one third of a sawfish’s body, “they aren’t the best shape for avoiding fishing gear,” says Duke. Often sawfish are killed or have their saws removed by fishers in attempts to untangle them from nets or fishing lines. Even if released alive, sawless sawfish are likely to slowly starve as their saw is used to find and capture prey. There has also been a large loss in coastal habitat, such as mangroves, which are used as nurseries by juvenile sawfish. “You can talk about so many different conservation issues surrounding sawfish, which has led to them being in the position that they are in today. While many species have suffered similar plights, sawfish are a great flagship species for the conservation of marine life,” comments Duke.

   Duke and the other organizers hope to further develop ISD and add on additional elements, such as fundraising, to support sawfish conservation in future years. She also noted that ISD is helping to bring together the people working on sawfish in all different disciplines and from various countries. “ISD will be celebrated all over the world and is as relevant in Australia as it is in the US, Africa, South America and Europe,” states Duke. She also commented on how everyone has a part to play in sawfish conservation and how ISD is a great way to unite everyone behind this common goal.


Children in awe of a green sawfish.
Photo credit: The Deep
   For those of you looking to participate in ISD this year, Duke had some suggestions on how you can get involved. A great way to reach a large audience is by sharing things about sawfish on your social media. The Deep aquarium is starting a Thunderclap, which will tweet out a united message about ISD and sawfish on each person’s Twitter that joins the Thunderclap. To join in on the Thunderclap, you can follow this link here: http://thndr.me/NIlkft. You can also follow the Sawfish Conservation Society on Twitter @sawfishconserv and Facebook, to stay informed on any events happening during ISD. Some other fun ideas are listed below:

Draw or create a sawfish and share your picture online.

Visit an aquarium or venue with activities going on for ISD (follow this link for a list of activities: http://www.sawfishconservationsociety.org/ISD4.html).

Take some interesting sawfish facts into school or your work place. You can learn all about sawfish and play sawfish games at www.sawfishconservationsociety.org

Bake sawfish shaped cookies and give them to your friends. Dress up as a sawfish!

Spark up as many conversations as you can about sawfish and why you think they are important.

If you see a sawfish saw somewhere, let researchers at The University of Southern Mississippi, Louisiana State University and the Sawfish Conservation Society know by emailing sawfishconservationsociety@gmail.com.

    Duke says the most important thing on ISD is to have fun, and if you have a genuine passion you can take that into your everyday life and be an ambassador for sawfish! 

Tuesday, January 24, 2017

En Busca del Pez Sierra en Costa Rica

Mario Espinoza y Jorge Valerio
Centro de Investigación en Ciencias del Mar y Limnología & Escuela de Biología,
Universidad de Costa Rica, 11501-2060 San José, Costa Rica



Nuestro proyecto “En Busca del Pez Sierra en Costa Rica” inició a finales de 2015 como una iniciativa de la Universidad de Costa Rica, en conjunto con Conservación Internacional y Misión Tiburón, dos Organizaciones No Gubernamentales. Este proyecto pretende impulsar una estrategia para la conservación del Pez Sierra en Costa Rica, y eventualmente extenderse a otros países de Centro América. Debido a que las poblaciones de Pez Sierra de Centro América han sufrido grandes reducciones producto de la sobrepesca y destrucción de los hábitats, resulta crucial identificar sitios en Costa Rica donde aún se encuentre esta especie. También es importante determinar las principales amenazas que afectan su sobrevivencia. Solo así se podrán desarrollar mejores medidas de manejo y conservación que permitan asegurar el futuro de esta especie tan amenazada.

Esta estrategia de conservación tan importante tiene dos objetivos principales: (1) evaluar la situación actual del Pez Sierra en Costa Rica; y (2) educar y concientizar a la población costarricense acerca de la importancia de proteger al Pez Sierra, principalmente a través de charlas, talleres y el uso de redes sociales.  El éxito de este proyecto depende de que diversos sectores de la población conozcan más a fondo a esta especie, su importancia ecológica, amenazas, y estado de conservación. Solo así se podrá asegurar la viabilidad de la especie a largo plazo.

Captura reciente de Pez Sierra (Pristis pristis) en Boca Tapada de San Carlos, Zona Norte de Costa Rica (marzo 2016).

Divulgación del proyecto a niñas y niños de centros educativos.
El proyecto también está generando información ecológica muy importante que permitirá evaluar la situación actual del Pez Sierra en el país. Por ejemplo, mediante el apoyo de Rufford Foundation hemos realizado un gran número de entrevistas a pescadores y miembros de comunidades costeras y rivereñas, lo cual nos ha dado una muy buena idea de la distribución histórica y reciente del Pez Sierra para Costa Rica. Estos esfuerzos se han enfocado en zonas costeras del Pacífico Norte (Cuajiniquil y Puerto Soley), Pacífico Central (Puntarenas, Golfo de Nicoya, Tárcoles), Pacífico Sur (Humedal Nacional Térreba Sierpe) y varios de los ríos de la Zona Norte (Boca San Carlos y Boca Tapada), cerca de la frontera con Nicaragua.  La gran ayuda de la gente durante el proceso de entrevistas ha sido invaluable para el éxito del proyecto.  El Pez Sierra, al ser un animal casi mítico, genera mucha curiosidad e interés en la gente.  A los más viejos, las entrevistas les trae gratos recuerdos de aquellos tiempos en los que tuvieron la suerte de ver o capturar un pez de tan extraña apariencia.  Es gracias a esa ayuda que hemos logrado recopilar información muy valiosa acerca de la distribución del Pez Sierra y las principales amenazas que afectan su sobrevivencia, particularmente en sitios cientos de kilómetros tierra adentro en la zona norte del país.

Las entrevistas realizadas hasta ahora demuestran que las principales amenazas del Pez Sierra en Costa Rica han sido y continúan siendo la pesca con trasmallos, la destrucción de los ecosistemas costeros y ribereños, y el cambio climático que ha afectado los caudales de los ríos.  La distribución histórica del Pez Sierra fue mucho más amplia de lo que esperábamos, siendo una especie muy común en muchos ecosistemas costeros y ribereños en ambas costas y zona norte de Costa Rica, mientras que su distribución actual parece que se ha reducido a unos pocos sitios del país.  Los pocos registros recientes de la especie (<2 años) se concentran en la vertiente norte (límite con Nicaragua) y en el Humedal Nacional Térraba Sierpe en el Pacífico sur; información necesaria para iniciar la fase de expediciones de campo.  Las entrevistas también nos han ayudado a evaluar la percepción de la gente hacia esta especie tan importante, así como identificar las posibles amenazas que afectan o han afectado históricamente la salud de sus poblaciones.

En 2017 comenzaremos la búsqueda del Pez Sierra en sitios que hemos identificado, a través de entrevistas y observaciones, como sitios importantes para la especie.  Tanto IDEAWILD y Rufford Foundation han colaborado con equipo y algunos fondos que nos permitirán realizar algunas expediciones.  Además, queremos aplicar otras técnicas más novedosas, como el uso de ADN-ambiental, una técnica capaz de detectar rastros de esta especie en muestras de agua tomadas del ecosistema. 

El Pez Sierra aún se encuentra en Costa Rica, pero su futuro es incierto. ¡Ayúdenos a salvar al Pez Sierra, seamos todos parte de esta gran iniciativa!

Puedes leer una versión en inglés de esta blog post aquí: 
http://sawfishconservationsociety.blogspot.ie/2017/01/looking-for-sawfish-in-costa-rica.html

Looking for Sawfish in Costa Rica

By Mario Espinoza & Jorge Valerio

Center for Research in Marine Sciences and Limnology & Biology School, Universidad de Costa Rica, 11501-2060 San José, Costa Rica.

Our project “Looking for Sawfish in Costa Rica” started late 2015, as an initiative of the Universidad de Costa Rica, in collaboration with Conservation International and “Misión Tiburón”, two local Non-Governmental Organizations. The project aims to promote a National Sawfish Conservation Strategy, which could eventually expand to other countries in Central America.  Given global declines of Sawfish populations due to overfishing and habitat degradation and/or loss, its crucial to identify sites in Costa Rica that may still hold a viable population.  It is also crucial to identify the main threats affecting their survival.  This will be essential to develop effective management and conservation strategies that may ensure the future of Sawfish.
 

This important conservation strategy has two main goals: (1) evaluate the current conservation status of Sawfish in Costa Rica; (2) educate and raise awareness to Costa Ricans about the importance of protecting Sawfish, mainly through talks, workshops, and the use of social media.  The success of this project will depend on the degree of awareness of Costa Ricans towards Sawfish, the ecological role this species play in aquatic ecosystems, major threats affecting their survival, and their conservation status.  Only then we may ensure a brighter future for the species.
Project outreach is being conducted in primary and secondary schools.

The information gathered through the interviews done so far demonstrate that in Costa Rica the Sawfish main threats continue to be fishing nets, habitat destruction, and climate change which has affected river discharges and water temperature. Its historical distribution was much broader than what we expected, being a very common species in many riverine and coastal ecosystems in both shores and in the north part of the country, while its current distribution appears to be more restricted to only a few sites. Recent sightings (<2 years) of Sawfish are concentrated at two main sites: (1) the north of Costa Rica, near the Nicaraguan border; and (2) the “Humedal Nacional Térraba Sierpe”, one of the most important wetland of Central America, located in the South Pacific.  Information on the distribution of this species is necessary to continue with the next phase of the project, which includes field expeditions. Interviews have also served to evaluate people’s perception of this important species and to identify the main threats that affect the health of their populations. 

Recent Sawfish (Pristis pristis) capture in Boca Tapada, San Carlos, northern part of Costa Rica (March 2016).
In 2017, we will start the search for Sawfish in sites previously identified from local interviews as hotspots for the species. This will be possible thanks to the support of IDEA WILD and the Rufford Foundation, as well as our local partners (Conservación Internacional and Misión Tiburón). Besides the ecological surveys, we are also planning to use environmental DNA (e-DNA), a novel technique capable of detecting DNA traces from water samples taken from the environment.

Sawfish are still present in Costa Rica, but their future is uncertain. Help us save our Sawfish! Together we can make a difference!


A Spanish version of this blog post is available at: http://sawfishconservationsociety.blogspot.ie/2017/01/en-busca-del-pez-sierra-en-costa-rica.html

Tuesday, March 29, 2016

Endangered Species Act Five-year Review and Recovery Plan Updates for US Smalltooth Sawfish, Pristis pectinata.



By Tonya Wiley-Lescher (Haven Worth Consulting)

The United States distinct population segment (DPS) of Smalltooth Sawfish (Pristis pectinata) was classified as Endangered under the US Endangered Species Act (ESA) in 2003. Recently I was contracted by NOAA Fisheries (National Marine Fisheries Service) to draft two key documents regarding the US population of Smalltooth Sawfish. 

The first document is an ESA 5-year review. To monitor recovery efforts and ongoing threats to the species, the ESA requires the status of the species be assessed through regular 5-year reviews. A 5-year review is an analysis conducted to determine if the current listing classification under the ESA is still accurate. The first review was completed in 2010 and, based on criteria established in the recovery plan, determined the species still warranted protections afforded by an Endangered classification. Our scientific knowledge of the species has grown considerably since then. So I am compiling all we have learned about this species of sawfish in the US, to determine if any recovery goals have been met. The second ESA 5-year review will, again, determine if the listing classification of Endangered under the ESA is still appropriate.

The second document is an updated Recovery Plan. A recovery plan for the US DPS of Smalltooth Sawfish was published in 2009 detailing goals and actions necessary to meet identified recovery criteria. Recovery plans serve as road maps for species recovery - they lay out where we need to go and how best to get there. Changes to the recovery plan, including revised recovery goals and criteria, are also underway. Updating the plan, and the recovery criteria it contains, will help scientists and managers work toward restoring the sawfish population in the US to the point where it is a secure part of its ecosystem and protections under the ESA are no longer needed. The US Smalltooth Sawfish Implementation Team will meet in April 2016 to finalize the updated plan and submit it to NOAA Fisheries to be reviewed and published. 
Tonya releasing a Smalltooth Sawfish pup.

To ensure these documents are based on the best available scientific and commercial data, public comments regarding US Smalltooth Sawfish can be submitted until March 22, 2016. I will be presenting the results of the second 5-year review and the updated recovery plan at the Biology and Ecology of Sawfishes symposium at the American Elasmobranch Society meeting in New Orleans this July. 

For more information on smalltooth sawfish, the Endangered Species Act, and US recovery efforts visit http://sero.nmfs.noaa.gov/protected_resources/sawfish/index.html


Monday, March 14, 2016

Team Sawfish: the extreme highs and lows of 2015

Team Sawfish’s 2015 was a year of extremes, not only for us researchers, but also for the sawfishes we study in Western Australia. Beginning the year with one of the driest wet seasons in the last 15 years, we knew we were likely to find low water levels and few young of the year sawfish, but we could not have imagined what surprises, good and bad, were in store for us.


Team Sawfish 2015. Dr David Morgan not pictured. Photo: Jeff Whitty

Our adventures began in early August, the early dry season, in the lower estuarine pools of the Fitzroy River. This time of the year is often ideal as the days are warm, nights are cool and rain is absent. By August, river discharge has fallen and the once flowing river is transformed into a chain of isolated pools. The small amount of river flow that remains and the relatively cold air temperatures keep the estuarine pools fresh and cool, with only the occasional spike in salt when the tidal waters intrude from nearby King Sound.  

The lower estuarine pool where we captured Dwarf Sawfish in August 2015. Photo: Jeff Whitty
 
During this early dry season excursion, we set out to continue our research on the Largetooth (Freshwater) Sawfish. However, the sawfish had other plans, as only Dwarf Sawfish, a marine species, were present. One after another, these fish filled our nets, an unusual occurrence for any sawfish species. We were not only surprised by the presence and numbers of the Dwarf Sawfish, but also by the salinity levels of the water, which were unusually high, being close to that of sea water, and the likely reason for the presence of the Dwarf Sawfish.

Knowing to never let a good opportunity pass us by, we decided to make lemon-aid from this lemon of a situation and tagged these Dwarf Sawfish with acoustic transmitters; a project (in collaboration with CSIRO) that was not due to start until October. This opportunity allowed for us to commence our study early, and collect months of data that we would have otherwise missed out on.  After deploying all of the tags that we had with us at the time, we departed with plans to continue to take advantage of this situation during our next field trip.

A Dwarf Sawfish tagged and released by Team Sawfish in the Fitzroy River in 2015. Photo: David Morgan

Returning in September, we once again were successful in finding large numbers of Dwarf Sawfish, at one point catching eleven within a single hour. Other fishers were also reporting unusual captures of marine fishes within the lower regions of the river, including hammerhead (likely Winghead) and Blacktip Sharks. We even had a surprise catch of our own. While fishing in the estuarine pools, we were ecstatic to catch the first ever Green Sawfish to be recorded within the Fitzroy River! Although we have observed Green Sawfish to use river mouths as nurseries, captures of this species in the King Sound are rare. 

Dr David Morgan with the Green Sawfish. Photo: James Keleher

Moving our efforts to the freshwater pools further upriver, we resumed our search for the Largetooth Sawfish. Despite high levels of effort, we encountered relatively few sawfish, a common trend over the last few years (likely due to the short wet seasons that have occurred during the same period). As the wet season size dictates the depth of the river, it also dictates how many sawfish can make their way to the safety and stability of the freshwater pools, and how many young of the year are recruited into the riverine nursery. As this dry spell has lasted several years, the only Largetooth Sawfish we observed in 2015 were those pupped in 2011. 

A sawfish cake. One of the few Largetooth Sawfish we saw on this trip.

In early December, our team found itself on the river once again, but this time amongst an unfortunate situation. Our team was informed by local residents that there had been a large die-off of sawfish and Bull Sharks in the upper reaches of the Fitzroy River.

Upon arriving at the site, the stench of death filled our noses and swarms of flies covered our faces. With the help of the locals, we recovered 12 Largetooth Sawfish, 8 Bull Sharks and a Whiptail Stingray, while also observing deceased catfish, cherabin (crayfish) and thousands of mussels floating on the surface of the water. Even arriving only a couple days after the deaths of the fishes, the now extreme heat and local scavengers had started to break down their bodies, making any autopsy and sampling of these animals near impossible. Despite the conditions, we collected what salvageable information we could, to ensure that this tragedy was not a total waste. 

Some of the Largetooth Sawfish and Bull Sharks killed by the low dissolved oxygen event in December. Photo: Jeff Whitty

Unable to determine the cause of death from the animals themselves, we turned to the environment to see if there was any evidence to suggest what happened. We deployed multiple sensors throughout the entirety of the affected pool to detect any abnormalities in the temperature, oxygen levels and pH of the water column; it was not long before we had identified the silent killer. There was very little oxygen below a depth of 1 meter and no oxygen below 2 m in this 10+ m deep pool. From interviews with local residents, we learned that a small rain event had washed oxygen-hungry organic matter into the pool. Without the additional input of freshwater, this organic sludge became concentrated within the single pool and likely absorbed the dissolved oxygen in the water, killing all bottom dwelling species. Similar occurrences have taken place in other seasonally flowing rivers in Australia but thankfully, residents said that this is a rare event in the Fitzroy River.

All in all, 2015 was an eventful year for the sawfishes of the Fitzroy River and Team Sawfish. Although we faced an number of unfortunate events, these unusual occurrences provided us with insight into how changes to the climate and environment can impact various species of sawfishes. As we move on to a new year of research, we are hoping to find a long and rainy wet season and a new batch of young of the year sawfish awaiting for us around the riverbend.




For more information about Team Sawfish and our work, please visit www.freshwaterfishgroup.com or like our Facebook page at https://www.facebook.com/Freshwater-Fish-Group-Fish-Health-Unit-342655079102312/?fref=ts. We would like to thank the Western Australia Marine Science Institute, Chevron Australia and CSIRO for funding these projects.