Monday, June 30, 2014

Sharks International- Durban 2-6 June 2014

Earlier this month the KwaZulu-Natal Sharks Board in Durban played host to the 2ndSharks International conference; a gathering of the world’s leading shark and ray researchers to update and share the results of their current findings. Oceans Research Director Enrico Gennari and I were in attendance and presented some of our current research to over 270 delegates from 37 countries. The conference was an overwhelming success with 169 oral presentations and 52 posters spread throughout the weeklong event.  David Shiffman, expert on all things Twitter, provided the ‘official’ reporting from the field, and many more contributed to over 7000 tweets at #Sharks14. For those of you that missed out on the action, David has taken a break from the conference dance floor and compiled a collection of selected tweets from the event here. What follows is a brief recap of the event.

The conference was opened with a message from MEC for Economic Development and Environmental Affairs, Michael Mabuyakhulu who reiterated the value of shark education for the economy of South Africa, and encouraged all in attendance to visitand spend their foreign currencies at Durban’s magnificent Gateway Theatre of Shopping. Dave Ebert, of the Pacific Shark Research Center in Moss Landing, California was the plenary speaker for the day and reiterated the value of morphological taxonomy in light of emerging modern tools like genetic microsatellites. Ebert has close ties to South Africa having completed his PhD studies at Rhodes University, and noted that southern Africa is one of the world’s hotspots for shark and ray biodiversity with a rich history of species discovery, but a surprising lack of young  scientists currently training in species taxonomy. The rest of the day saw many of our colleagues presenting their work on white sharks in South Africa, with notable talks from Alison Kock presenting the culmination of her PhD on sexual segregation in False Bay, and Enrico Gennari, presenting his PhD on the metabolism and behaviour of the white shark in Mossel Bay.

Despite the unsuccessful efforts of a small group of protestors to disrupt the proceedings of Day 1, Day 2 began unimpeded with a plenary from Demian Chapman. Chapman shared his team’s genetic work on identifying species and populations of sharks traded on the shark fin market, noting that the potentially endangered guitarfish could be one of the highest value species on the market. In addition to identifying which populations are most affected by the fin trade, Chapman’s team also trains customs officials to identify fins that are illegal to trade. Notable talks from Day 2 included those from the genetics department at Stellenbosch University, and the plethora of Telemetry talks from the likes of Steven Campana, Philip Doherty, Neil Hammerschlag, and Christoph Rohner. And naturally, my talk on the lifetime of SPOT tag technology her in South Africa, for which we received some coverage in the local paper.

On Day 3 the organisers saw fit to provide us with a much needed mid-conference break from the overload of day-time academia and night-time socialising. Many delegates spent the day diving at nearby Aliwal Shoal or on game drives at some of the area’s private reserves. Rumours of an out-of-season Whale Shark spotting spread quickly, leaving those that opted out of any tours green with jealousy.

Day 4 picked up right where we left off on Tuesday with a plenary from Colin Simpfendorfer of James Cook University in Australia. Simpfendorfer shared recent findings that upwards of 25% of shark and ray species are threatened with extinction, and almost half are listed as ‘Data Deficient’. Much of the focus has been on shark populations but rays are bearing much of the brunt. #RaysNeedLove2. For some parts of the developing world, shark fishing is a matter of survival, and some of these species can be sustainably fished, but only with sound, science-based management. Ultimately it is a lack of scientific understanding that makes fisheries management difficult. The days professional and student talks were dominated by the fisheries theme, but the standout talks for me were those from Shaun Collin’s lab of sensory biologists at UWA: Kara Yopak, Ryan Kempster, Laura Ryan, and Lucille Chapuis. And of course our colleagues in False Bay and Gansbaai speaking on the population ecology of the white shark.

And lastly, Day 5 began with an entertaining plenary by University of Windsor’s Nigel Hussey who spoke about the growing field of trophic ecology. Stable isotopes in elasmobranch tissues can be used to reveal the entire story of a shark’s diet, revealing a much wider range of diets on both the individual and species levels. The first Sharks International conference in Cairns, Australia featured 2 presentations on Stable isotope research. This year there was an entire plenary and themed section on trophic ecology research. Friday also saw an entire presentation section dedicated to research on the severely threatened sawfish, perhaps one of South Africa’s first marine extinctions. Other notable talks were those on shark attack mitigation and shark control measures, with a particular standout for me from Francesco Ferretti and his talk on modelling shark attack data along the California coast.

The close of another successful Sharks International was celebrated Friday night with a gala dinner and dancing, where awards were handed out, and the announcement was made that the Brazilian Shark and Ray research community, SBEEL, will be the host of Sharks International 2018. Looking forward to seeing you all again in 4 years in João Pessoa!

Dylan Irion

Friday, June 13, 2014

Wildlife Research Unit kicks off

Oceans Research has evolved and crawled out on land, and so we have started with land based research with one intern and five projects. The studies were conducted on two private game reserves in close proximity to Mossel bay. The small mammal survey and bird surveys were done at Botlierskop for safety reasons, as the Lion on the reserve is kept in an enclosure and not free roaming as is the case on Gondwana Game Reserve.

 The month kicked off the first week of Training. Camping at a water hole overlooking the rolling hills covered in indigenous fynbos must have been an experience for anybody with a love for nature. The campers were reminded of the force of nature when a huge wind storm blew the tents down on late Sunday afternoon and were they forced to seek shelter from the elements. Replacing all damaged equipment on Monday morning, they returned to the field to resume their field work.

We started our research work at Botlierskop on Monday morning with our new set of 4x4 wheels called “THE AARDWOLF”. Two small mammal trapping grids were laid out with 25 traps each.  We focussed our efforts in two habitat types, fynbos and grassland.

After finishing our packed lunches, we set out to look for suitable places to deploy the two camera traps. Both were eventually deployed in two separate river beds where we expected game movement.
For the next three days we checked the traps every morning, for small mammals and after the first two escaped we had our skills honed and marked and weighed a total of 19 mice. We took 17 tail clippings for DNA analyses.

The afternoons were spent doing the behaviour study on the Giraffe and some interesting interactions were seen as one female is expected to be pregnant and the other female being in oestrus.
Week three was focussed the behaviour study and bird surveys and tracking at Botlierskop and Gondwana.  

The last week were put aside for tracking and the giraffe behaviour study. We tried to find the cheetah, but could not get to see them but got a good fix on their general position. We focussed on the behavioural study on Tuesday and Wednesday being our last day at Gondwana we tracked the Rhino and were hoping to see the elephant as both these pachyderms were not seen by us.  After finding them we spent the afternoon following their movements in the valley until they moved into the thicket and could not be seen anymore.

On Thursday morning we went out to Botlierskop to retrieve the camera traps and the afternoon was put aside for downloading and analysing the images. We were quite disappointed about the results, as we only recorded a waterbuck and eland on the one trap, and a giraffe on the other. I am planning to place the traps on existing game paths where there are good visibility for the next session. But that is what research is all about: not always a success. To be continued...

Small aquarium... wide research niche

The Shark Lab and Research Aquarium initially functioned as both a public aquarium and a unique research facility, offering South African and International students alike the opportunity to advance their academic careers. Most recently, this facility has realigned its focus and functions primarily as a research unit.

In a world where human pressure is threatening entire ecosystems, the need to understand the individual elements that make up such systems becomes progressively more urgent and the research required to achieve these goals, become paramount. Research projects conducted at the Shark Lab and Research Aquarium therefore are of great value to and dovetail with conservation efforts on an international scale.

A number of honours and masters projects have been completed at the Shark Lab and Research Aquarium. A project titled “Temperature Niche of Four Benthic Shark Species”, conducted by honours student R. Lombard, from the Department of Zoology and Entomology, University of Pretoria, aimed to show how benthic sharks react physiologically to ambient temperature changes in their environment by assessing respiration rates as an indicator of abiotic tolerance. An additional aim of this project was to ascertain if dissolved oxygen is the major driver of respiration as opposed to temperature, as well as to assess if any variations in responses occur amongst the three species used in the experiment. The species used, being the leopard cat shark (Poroderma pantherinum), pyjama cat shark (Poroderma africanum) and the puff adder shy shark (Haploblepharus edwardsii).

A second honours project, conducted by honours student, Monica Betts, also from the Department of Zoology and Entomology, University of Pretoria, was titled, “Intraspecific and Interspecific Interactions of Benthic Sharks”.

This study aimed to determine the interspecific and intraspecific interactions of benthic sharks through a series of manipulative laboratory experiments. These insights into how three otherwise similar benthic species interact in a captive setting under the same controlled environmental conditions, will hopefully inform on their inter-relationships in nature.

Questions posed for this project, considered the response of different individuals of conspecific sharks to the tank environment, the responses compared amongst the three species of benthic shark, the response of an individual shark in the tank environment to the presence of one, or more conspecifics, the response of an individual shark in the tank environment to the presence of one or more heterospecifics and how the findings of this study reflect on the likely interspecific relationships of the three benthic sharks in the wild

Current research projects at the Lab include amongst others, a Cognition experiment and a Tonic Immobilization study, as well as a project to determine the growth rates of select benthic shark embryos and a project looking at stress in select pelagic shark species. These species being the leopard cat shark (Poroderma pantherinum), pyjama cat shark (Poroderma africanum) and the puff adder shy shark (Haploblepharus edwardsii).

The tonic immobilization study examines various factors which may affect TI behaviour of three species of scyliorhindae. The aims of this study are to investigate differences in TI behaviour between dependant variables, such as success rate, time in tonic, time taken to go into tonic, and the tenseness or calmness of the individual specimens. These factors are then compared between various independent factors, which include species, gender, and size and respiration rate. Variation in responses is then used to critically compare and interpret the potential biological significance of this behaviour.

The Cognition project aims to assess the relative learning capabilities of the three benthic shark species already mentioned, using an open plan choice-based maze. These sharks are conditioned to distinguish a visually distinct colour, using food as a reward. Furthermore, the different species will be used to ascertain if differences in learning behaviour exists between benthic species.

Questions that were asked during this project included the following: Can these species of benthic shark be conditioned to associate a visually distinct colour by using food as a reward?  Is the ability to condition sharks to associate a visually distinct colour with food independent of shark species and is the duration that the conditioned response persists independent of shark species?

The aim of a very recent egg project is to gauge the growth rates of the embryos of select benthic shark species in different temperatures as well as the growth rate between these species. A minilogger is used to obtain the average temperature of ocean water in Mossel Bay to most accurately duplicate this temperature in the research tanks.

Over the previous two years, two masters projects have also been completed at the Shark Lab and Research Aquarium.

One of these projects, titled “Occupational patterns of sharks in Mossel Bay as a function of air and hydrostatic pressure”, looked at understanding the functional behavioral responses of the three previously mentioned benthic shark species as a result of the environmental factors. The researcher, Tristan Scott from the Department of Zoology and Entomology, University of Pretoria, wanted to demonstrate that movements in these species may be related to atmospheric pressure declines associated with approaching storms.

Dylan Irion from the University of Cape Town, also completed his masters titled “Identification of the Swimming Behavior of the common smooth hound shark (Mustelus mustelus) based on TriAxial Accelerometer Data”, at the Shark Lab and Research Aquarium.

Alan Jardine - Aquarium manager

Tuesday, April 29, 2014

Research with Bite: Ocean Research’s Project Great White Shark in 2013

It was another exciting year in 2013 at Oceans Research for Project Great White Shark where research continues in the beautiful Mossel Bay. As we approach the exciting months of winter a.k.a “breaching season”, it seemed the perfect time to reflect on the past year of research and what our staff and interns have observed so far in 2014.
The aim of Project White Shark is to identify the spatial patterns in relative abundance, and investigate the size composition to define the population structure for white sharks in Mossel Bay. Oceans Research also aims to establish an index of abundance for white sharks in this area to better our estimates for their global population size. In simpler terms, we want to know how many sharks are in the bay at different times of the year, what areas they are concentrated in, what sizes are found in the different areas across seasons, and also, if individuals are staying in the bay year-round or moving away for months – even years – at a time.
In 2013, Oceans Research interns collected data for Project Great White Shark across 314 sampling trips to the various sites in Mossel Bay (34˚ 11’ S, 22˚ 09’ E; Image 1) totalling a massive 782 hours of sampling effort! Each trip averaged 2 hours and 49 minutes of sampling and with a total of 1,547 recorded white shark sightings, each trip averaged 1.96 shark sightings per hour (sharks per unit effort; SPUE).

Image 1: Sampling sites for Project Great White Shark within Mossel Bay, South Africa.

The below graph (Image 2) represents the average number of sharks observed per unit effort (hour; SPUE) across each of the four seasons in 2013, with the winter months corresponding to the highest value of 1.97 SPUE. In comparison to the average SPUE of 1.83, this peak in the winter months is correlated to the movement of white sharks to Seal Island (approximately 800 metres from shore) where the Cape Fur seal pups begin to enter the water for the first time since their birth in November/December. The lack of experience of these seal pups in identifying and avoiding strikes from their large predators makes them easy targets in their new aquatic environment during this time of year, thus providing the perfect feeding opportunity for the larger marine-mammal consuming sharks in Mossel Bay.
Image 2: Average number of sharks per unit effort (hour; SPUE) observed across seasons in Mossel Bay in 2013.
White sharks ranging from 125 – 474 cm total length were observed in 2013, with just under 75% of recorded individuals being placed in the 175 – 324 size range. Larger sharks (325 – 474 cm total length) comprised 17% of the recorded individuals, with sharks ranging from 125 – 174 cm total length making up the last 9% of observed white sharks for the year. Already in 2014, two of these larger individuals have already been sighted with total lengths estimated to be 470 and 500 cm! It will be very interesting to see if these sharks hang around until later in the year!
In terms of white shark activity for 2013, Seal Island and Blue Houses sites were observed to be the focal areas (areas of highest activity) in the seasons of winter and summer respectively in Mossel Bay. Image 3 presents the average SPUE observed across all of our study sites for 2013, and illustrates the higher SPUE for Seal Island (1.88) and Blue Houses (1.43) in comparison to the average of 0.86 SPUE and this pattern has been observed for the last few years. The peak SPUE value at Seal Island is a result of the previously discussed movement of white sharks to the area for winter’s ‘breaching season’, as the young seal pups of the year enter the water for the first time and provide easy high-energy prey targets. The high SPUE witnessed at Blue Houses is correlated with this site being the focal area for white shark activity in the summer months. 

Image 3: Average number of sharks per unit effort (hour; SPUE) observed at the six sampling sites in Mossel Bay in 2013.
A lack of inexperienced seal pups entering the water in summer in comparison to in the early winter months drives the white sharks to move across the bay to the reef systems of the Grootbrak area - the Blue Houses site in particular - to utilise the fish stocks that reside there. The river systems and mouths located between these two focal sites (Hartenbos, Kleinbrak, and Grootbrak rivers) provide resting areas for the sharks between hunting trips, which is a potential reason why we see less sharks in these areas as they could be less attracted to our baits due to the fact that they might have already hunted and fed. The dynamic nature of the white shark population across the sampling sites for Oceans Research in Mossel Bay is illustrated in Image 4 below, which shows how SPUE vales for each of the locations changes throughout the year. The movement of Mossel Bay’s white sharks from Blue Houses to Seal Island and back as winter comes and passes can also be seen below.

Image 4: Number of sharks per unit effort (hour; SPUE) observed throughout 2013 at each of the sampling sites for Project Great White Shark in Mossel Bay.
In previous years of this study (2013 included), the movement of white sharks from Blue Houses to Seal Island has been observed to occur around the end of March – early April however, in 2014 this movement was noted to have occurred in early March. The precise reason for this early movement is not currently known but possible explanations include changing fish stock supplies and varying environmental cues.
Another interesting observation made by Oceans Research across the summer of 2013 and 2014 was the predominance of “red-tide” algal blooms that entered the bay quite frequently; some days reducing the visibility in the water to less than one metre! It is unknown what is driving these intense algal blooms and which species of algae are causing this problem, however we have seen that these events have the potential to reduce the number of shark sightings made on sampling trips (even in focal areas).
As well as heading out into the field to conduct research for Project Great White Shark, Oceans Research also aims to educate and involve the community in our research. Numerous meetings have been held with the surfing community of Mossel Bay since the beginning of 2014 to explain how we execute our research and discuss the highly contentious issue of chumming. These meetings aim to explain to the public the science behind why we chum, and the minimal to negligible impact our methods and protocols pose to shark behaviour and water-user safety. It also provides the perfect opportunity for people to ask questions or raise concerns directly to the staff of oceans, and even to make suggestions about how we can improve how we communicate our research and actions to the public. A great example of how communications between Oceans Research and the public is increasing is the initiation of a “chumming flag” system during research trips to study the white sharks. When chumming on these trips, a white flag with a black profile of a shark (Image 5) is flown from the research vessel so that it can clearly be seen from land. This allows people on the beach to know if our vessel is chumming or not (in the latter case, this means that research is being carried out for other projects in the bay).
Image 5: Oceans Research intern, Michele Donihe, and Field Specialist, Curtis Young, on the look-out for white sharks during a chum trip. The chumming flag (white flag and black shark) is flown from a Oceans Research vessels whenever chumming is being performed.

It’s been an exciting year so far on the waters of Mossel Bay in early 2014 for Project Great White Shark, and with breaching season just around the corner, everyone is very excited because....

Lauren Peel
Oceans Research