Ray tagging with the Mother of Rays

​Joni Pini-Fitzsimmons and TFUI Founder Melissa recently met at a conference and hit it off with a mutual love of #flatsharks. Joni was kind enough to allow TFUI to interview her on her experiences with tagging rays, her MSc project and her newest endeavour: the Stingray Diaries!

​The Stingray Diaries aims to make people as cr-RAY-zy about rays as anyone else who loves these majestic sea flap-flaps. If you live in Jervis Bay, Australia, you can help out Joni and the Stingray Diaries by reporting a sighting of short-tail stingrays.

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Photo credit to Johann Mourier

TFUI: Thanks for joining us, Joni. Can you tell the TFUI readers a little about you and your project?

Pini-Fitzsimmons: My name is Joni and I am a Masters of Research candidate at Macquarie University working in the Behaviour, Ecology and Evolution or Fishes lab under Associate Professor and fearless leader Culum Brown.

Broadly speaking, my research is aimed at providing a better understanding of the world’s largest species of marine stingray – the short-tail stingray or Bathytoshia brevicaudata. This species is huge – it grows in excess of 2.1 meters wide and over 350kg! They are a common coastal species throughout southern Australia, New Zealand and South Africa, as well as Japan and eastern Russia. They are also commonly kept in public aquariums. Given this, it may surprise you to know that we know almost nothing about them. This is primarily due to confusion with other large species of stingray, such as Bathytoshia lata (formerly Dasyatis thetidis) and quite plainly, a considerable lack of research into them.

Currently, my research focuses on providing the first comprehensive assessment of the short-tail stingray population of Jervis Bay, NSW, Australia, primarily focusing their site use and interactions with humans in the waterways of this popular coastal town. The waters of Jervis Bay also make up the majority of the Jervis bay Marine Park.

TFUI: So what is so special about Jervis Bay?
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Pini-Fitzsimmons: In Jervis Bay there has been a 30-year history of a small sub-population of short-tail stingrays scavenging fish scraps that are discarded by fishermen at a popular public boat ramp within the Currambene Creek. These rays are there almost daily and the old local fishermen have become very attached to them – giving them names, getting in the water with them, hand feeding them. It’s really quite a sight.

Through logging observations of stingray visitation, boating activity and fish cleaning activity at this site, we hope to quantify how tuned in these stingrays are to this provisioned food source. Do they wait in anticipation? Or how long after fish cleaning do they arrive? Are there ‘regulars’ who are there every day? Is there a dominance hierarchy between them?

In the future we hope to acoustically track these stingrays throughout the marine park to try fill some of the knowledge gaps in the biology and ecology of this species.

TFUI: WOW! Seems you have your hands full! Can you tell us more about your study species, the short-tail stingrays?

Pini-Fitzsimmons: Short-tail stingrays are also commonly referred to as smooth stingrays. They were formerly assigned to the genus Dasyatis; however, a recent taxonomic review reassigned this species to Bathytoshia.
 
This species is listed as ‘Least Concern’ on the IUCN Red List of Threatened Species, due predominantly to their “wide distribution, abundance, and limited fisheries mortality”. However, even their distribution is an aspect of debate, with the population off the coasts of Japan and Peter the Great bay, Russia previously being assigned to Dasyatis matsubarai but now considered to be the same species. Almost nothing is known about their home range, daily and seasonal movements, behaviour, sociality and reproduction, including their size and age at sexual maturity, length of gestation, reproductive periodicity, and the locations of pupping and breeding grounds.
 
Much of what we do know comes from the work of Dr. Agnes Le Port on the population that uses Poor Knight Island in New Zealand (see (Le Port and Lavery, 2012, Le Port et al., 2012, Le Port et al., 2008)). These stingrays form a huge breeding aggregation at this site, which is the only aggregation described for this species. It is likely that this is the case for other populations of this species, so it is important to identify the locations of these sites for the conservation and management of this species.

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Photo credit to Johann Mourier

TFUI: Can you describe what tagging is?

Pini-Fitzsimmons: Tagging animals is a tool scientists use to mark individual animals in order to track their movements. Whilst for some animals you can use natural markings, like the spots on whale sharks and giraffes, which are as unique as our fingerprints, for other animals scientists need a little help in identifying individuals.

Tags can be external or internal. External tags can be used simply for identifying an individual by sight, such as by colour coding or numbering, for example bird banding. External visual tags are useful for mark-recapture studies.

Electronic tags can also be attached to an animal externally. These include archival tags and pop-up satellite archival tags (PSAT), which collect data such as water temperature, acceleration, depth and GPS location, which are stored on the internal memory. With archival tags, scientists need to recapture the animal to remove the tag and download the data. PSAT tags ‘pop off’ the animal after a predetermined time after which scientist head out to find the tag using GPS and download the data. These electronic tags are useful for long term tracking of species

Acoustic tags can also be affixed externally, but more commonly they’re surgically implanted. These tags have a unique acoustic signature, which ‘pings’ off what’s called a receiver array that is set up in the area of interest. If a tagged animal swims within a certain distance of one of the receivers in the array the receiver will log the ID and time that animal was in that area. These data are useful for tracking small and medium scale movements. 

TFUI: Do scientists need permissions to tag animals?

​Pini-Fitzsimmons: If you want to do so much as look at an animal for scientific purposes you will need permission. Any research involving animals, including observational science, manipulative experiments, tagging, and everything else, must comply with certain legislation and guidelines. In Australia, it must comply with the Australian Code for the Care and Use of Animals for Scientific Purposes from the NHMRC. All scientific institutions in Australia have an Animal Ethics Committee to which an application must be made. No animal research can be carried out without the approval of the AEC.

Other permissions you need are dependant on where the research is to take place. For example, my research takes place in a marine park and therefore I require a Scientific Collection Permit from the NSW Department of Primary Industries. This permit stipulates the exact activities I am approved to undertake, the locations in which I can undertake them, and other specific conditions under which I can conduct the research.

Another permission I require for my research is from the Biosafety Committee at Macquarie University. As the tagging I undertake may result in me coming into contact with some biological material – i.e. stingray skin or muscle tissue. Whilst unlikely there is still a possibility and biosafety approval is necessary.

TFUI: What are you tagging rays for and what type(s) of tag(s) are you using?

​Pini-Fitzsimmons: At this stage in the project I am tagging the stingrays with visual tags so I can identify them by sight during my observations. By tagging the rays visually I can easy tell who is at the study site and when, which I can then compare to fish cleaning and boating activity to determine the level of human interaction there rays are experiencing. I am also using the visual tags to know who is who in social interactions, which will shed some light on the social structure of the sub-population using the study site.
 
The tags I am using are called spaghetti tags with stainless steel dart (SSD) heads and they are made by a company call Hallprint Fish Tags. The dart head is shaped and sharpened to allow it to be easily inserted in the upper musculature of the stingray on their dorsal surface by use of a tagging pole. The dart head is made from marine grade stainless steel which is highly resistant to corrosion which is useful in the tagging of saltwater species.
 
All that you can see once the ray is tagged is the spaghetti part, which, as the name suggests, looks like a bit of spaghetti hanging off the ray. This part is about 15cm long and each tag has a number and a unique combination of 2 colours. This colour coding is how I can tell the rays apart during observations.

TFUI: Why did you choose that specific tag type over others?

​Pini-Fitzsimmons: Choosing the most suitable tag for tagging studies can be a long process, which often involves an extensive review of the literature to see what other researches have used in similar studies and well as discussion with tag manufacturers and experts in the field.
 
Many catch and release studies in marine animals involve either PIT tags, the same thing as dog and cat microchips, or external visual tags. PIT tagging was an option but at the beginning of the project we had hoped to use camera equipment to track the stingrays site use for which we would need some kind of external tag that made it easy to identify individuals.
 
So what we needed was a visual tag that was quickly and easily attached to the animal by use of a tagging pole to ensure myself and the team had enough distance between ourselves and the ray, eliminating the risk of coming into contact with their 30cm serrated tail barb. The tags needed to be individually distinguishable from up to 5m away, but small enough to not cause drag on the animal or on the tag wound, which would create issues for the wound healing. We also knew it wasn’t a particularly long project either so the life expectancy of the tags only needed to be abut 1 year.
 
At this stage I had lengthy discussions with my supervisors and David Hall of Hallprint Fish Tags. David suggested the SSD spaghetti tags based on their low cost, ease of application by tagging pole, minimal drag and the ability to produce them uniquely colour coded.

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Photo credit to Johann Mourier

TFUI: What are the challenges to tagging rays?

Pini-Fitzsimmons: The biggest challenge is when the rays just don’t show up. One of the biggest challenges of any work with wildlife is you can’t always predict where they will be and when. We have been lucky at our study site as the rays are pretty predictable, but we have had times where the rays haven’t turned up for a number of days at a time, which is interesting in itself and something we will looking at in the future. I want to know where they go and why, when they have such a good deal at the study site with all that free fish. It goes to show just how little we know about them.

TFUI: Does tagging hurt rays? 

Pini-Fitzsimmons: Recent research shows that the sensory receptors (known as nociceptors) responsible for feeling pain in humans and other mammals are not present in the sharks studied to date.  Moreover, many tags are attached to shark fins, which have no nerve supply. [No further comment]

TFUI: Why do we need to tag animals? 

Pini-Fitzsimmons: Some animals are particularly elusive, which can make it impossible to study them. In the marine realm this is particularly true. Tagging allows scientists to track the natural movements of animals – something that would be impossible without visual and electronic tagging technology.
 
Tagging animals with visual tags allows us to conduct mark recapture studies, which help us understand population size. It also allows us to collect data on species distribution and migratory patterns. This provides a cool opportunity to get the public involved in what’s termed ‘Citizen Science’. This involves scientists tagging some animals and then asking the public to report their sightings. This is something we actually are asking the community of Jervis Bay for this project. We have a website where the public can report any sightings they have made of short-tail stingrays, tagged or not, in the greater Jervis Bay area! Visual tags are particularly useful for small areas and animals that are reliably resighted.
 
Whilst visual tagging is important, animals have to be re-sighted or re-captured. Electronic tags have helped provide an alternative. Using acoustic or archival tags, all the scientists have to do is attach the tag and send the animal on its’ way. This significantly reduces the time and costs associated with animal research. Electronic tags are particularly useful for mapping entire migration routes or movement patterns, where re-sighting data from visual tags can be patchy.

TFUI: What does the tagging data help show? 

Pini-Fitzsimmons: One particular benefit of tagging studies is in the protection of threatened and ‘data-deficient’ species. Tagging and tracking can shed light on some basic biological traits which can help in the conservation of the species. This include identifying key behaviours, such as schooling and diel movements, the location of key habitats for foraging and breeding, and migratory patterns. The determination of migratory patterns can be particularly useful for managing human impacts on the species, with is a key threatening process for almost all threatened species.

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the fins united initiative would like to thank joni for her time and 
we wish her well on her current/future projects! 

SAY HELLO!

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