The Whale Coast of South Africa’s Western Cape province is considered to be amongst the most important conservation areas for marine mammals in Africa. It is named after its large number of southern right whales, but several other cetaceans, i.e. whales and dolphins, also inhabit these exceptionally rich coastal waters.
The Whale Coast Cetacean Project is the first thorough, long-term scientific study of the whales and dolphins in the area. It aims to understand the importance of the Whale Coast for the various cetacean species, both from a biological and conservation perspective. It is hoped that the results of the project will contribute to the development of an appropriate, targeted, and viable conservation plan for the previous and unique Whale Coast.
The overall research goal of the project is to achieve a thorough understanding how how whales and dolphins utilise and depend on the study area.
This study is novel in its approach as it uses cutting-edge methods. The project combines the use of passive acoustic monitoring, theodolite tracking, photographic identification, and opportunistic observation data over a 10-year period from the whale-watching vessel at Dyer Island Cruises. By using such an array of complementary research techniques, the study should generate a comprehensive understanding of the complex ecological relationships and behaviours of cetaceans in the Dyer Island area.
Researcher: Katja Vinding PetersenRegion: South Africa
Organization: University of Pretoria & Whale Coast Cetacean Project
MSc from the University of Copenhagen
BackgroundThere is an urgent need to monitor and protect the marine environment in the Greater Dyer Island area. The Western Cape’s south coast is facing potential development including oil and gas surveying, extension of harbours and gas offloading facilities and desalination plants. Collecting data now is therefore important as the area is already impacted by various human activities. These include:
Tourism and leisure boats
The area is highly important as a recreational and tourism location. Depending on weather, the eight shark cage diving boats and two whale watching boats use the area on a daily basis. There is strong evidence showing clear behavioural changes in many species of cetacean caused by boat traffic, including horizontal avoidance, longer dives, increased speed and changes in vocalisation. More recently, longer term studies have shown that these short-term behavioural changes may accumulate into larger population-scale effects including temporary and permanent emigration of some individuals from key habitats.
Nuclear power station
The potential impacts of a nuclear power station include: increased water temperature (estimated increase of 12°C around outlet pipes), increased background noise, up to 10.07 million m³ of sediment discharged into the water column, water intake and output (with risk of animals being sucked in) and contamination (chlorine and sewer discharge during pipe cleaning and flushing). It is not known how these impacts will affect the cetaceans in the area.
Part of the study has involved the analysis of 10 years of opportunistic observations (from 2003 to 2012), collected from the commercial whale-watching vessel operated by Dyer Island Cruises. This analysis identified five species of cetacean which are seen regularly in the research area: Indo-pacific humpback dolphin (Sousa chinensis. Plumbea form), Indo-pacific bottlenose dolphin (Tursiops aduncus), southern right whale (Eubalaena australis), humpback whale (Megaptera novaeangliae), and Bryde’s whale (Balaenoptera edeni).
ObjectivesThis study will address the following questions:
- What is the seasonality of cetacean species using the area?
- How long do the different species of cetaceans stay in the area?
- Do different cetacean species use the area differently?
- Do certain individuals use the area more frequently than others?
- What types of behaviours are observed in the area?
- What is the seasonal pattern of the different types of behaviour?
- How vocal are the cetaceans in the area?
- What are the seasonal and diurnal patterns of vocalisation?
- Can we use these vocalisations to monitor cetacean habitat use?
This next phase of the project will focus specifically on the seasonal and temporal distribution of the five main cetacean species in the area. It also aims to develop future monitoring protocol for coastal cetacean species in South Africa, involving passive acoustic monitoring.
MethodologyThe project uses an innovative combination of several non-invasive monitoring methods to study the whales and dolphins:
Observations by whale-watching vessel
A local whale-watching vessel collected observation of cetaceans in the study area from 2000 to 2012. A vigorous analysis of this data set has given a valuable first insight into the occurrence of the various species of whales and dolphins and has yielded the development of guidelines for future data collections. The analysis phase of the project has been concluded.
Land-based theodolite observations
From August 2011 to December 2014, observations of cetaceans have been conducted from two land-based observation points in Pearly Beach using land-surveyors’ theodolites. This cost-effective method allows a large area to be surveyed at one time, providing an unprecedented comprehension of habitat use, spatial distribution, social behaviour and season occurrence of the whales and dolphins.
Recording cetaceans using acoustic loggers
Whales and dolphins are highly vocal animals and their sounds can be recorded over a long distance using specially-designed acoustic recorders, or loggers. In September 2013, an acoustic logger was moored on the sea floor in the Pearly Beach area within sight of the shore-based theodolite stations.
The logger sampled up to 80 kHz, allowing recording up to 40kHz, covering the majority of frequencies used by dolphins and all the frequencies used by baleen whales. Using this in combination with the theodolite enables the project to establish:
1) the vocalisation rate of the animals in the area,
2) the recording range of the acoustic loggers, and
3) the probability of recording different species and differentiating between them.
Southern right whale photo ID
This ongoing project aims to create an identification catalogue for southern right whales based on two substantial photo archives from the Walker Bay and Pearly Beach areas. The characteristic head callosities of these whales allow for individual recognition and an ID catalogue can provide information on time spent in the area and special sightings such as orphaned calves.
Annual Report, February 2016
Three methods were used to investigate the occurrence, behaviour, spatial distribution, and temporal distribution of cetaceans in the Dyer Island area, Western Cape, South Africa.
1. An analysis of historical data from a local whale-watching vessel (WWV) consisting of more than 5 500 cetacean encounters in more than 2 500 trips between 2003 and 2012. The analysis revealed that the study area is regularly frequented by five cetacean species:
• Southern right whale Eubalaena australis
• Humpback whale Megaptera novaeangliae
• Bryde’s whale Balaenoptera brydei
• Indian Ocean humpback dolphin Sousa plumbea
• Indo-Pacific bottlenose dolphin Tursiops aduncus
Three other incidental visitors were: common dolphins Delphinus spp, killer whales Orcinus orca and Heaviside’s dolphins Cephalorhynchus heavisidii. Southern right whales were by far the most common with a marked seasonal presence from August to December.
2. Shore-based observations, using a surveyor’s theodolite (during four southern right whale seasons consisting of 1 558 hours (1 204 scans) over 270 days between 24th August 2011 and 11th December 2014. This enabled behavioural analysis and confirmation of spatial and temporal distributions obtained from the historical data. The area is an important location for nursing and socialising southern right whales; it is part of a migration route of humpback whales and may be a summer feeding area for Bryde’s whales. Finally, it was found that the area serves as a year-round socialising and resting area for the two dolphin species.
3. Passive acoustic monitoring (PAM) using a single bottom-moored hydrophone to obtain sound recordings over 44 days: three periods in January/February, September, and October 2014. PAM was used simultaneously with the theodolite observations to investigate vocalisation patterns of southern right whales. Two types of sounds were used in the analysis and compared to the number of visually counted animal group types.
Southern right whale sounds were recorded 79% of the time that they were visually present, indicating that PAM is a useful technique when monitoring the presence of this species but, with simultaneous occurrence of several group types, it was not possible to correlate specific behaviour or group type to specific sounds.
PhD study of the identification of whales and dolphins in South Africa’s coast started on schedule in January 2012 and the final year has commenced in 2015. In the past years, Katja has coordinated the daily fieldwork and trained and managed the volunteer students in fieldwork, data collection and analysis. In addition, she has so far completed three articles. Her thesis is currently planned as five data chapters, which will be written up as scientific publications.
2014 was a very successful year where the final collection of baseline data on the cetacean species in the coastal area adjacent to Dyer Island, Western Cape, South Africa, was completed. The acoustic logger was deployed and sound recordings from southern right whales, humpback whales and inshore dolphin species were obtained. The land-based theodolite tracking was empowered with a custom-made live tracking programme “VADAR” which enabled the team to follow their sightings instantaneously. Visual data will be analysed in relation to the acoustic data to establish a method for passive acoustic monitoring of the inshore cetacean species.
Preliminary analysis has identified songs from humpback whales, whistles from humpback dolphins, and confirmed that the southern right whale surface active groups (SAGs) are highly vocal. Next is the analysis and investigation of the vocal patterns of SAGs, vocal behaviour of cow-calf pairs, and if possible, distinguishing the different inshore dolphin species acoustically.
Very successful tests of bottom-moored hydrophones, heat-sensitive cameras and an acoustic drifting buoy in Walker Bay were conducted in collaboration with Seiche Measurements, a leading company within the field of measuring and analysing underwater noise and mitigating impacts on marine mammals.
Other collaborations include one with Shark Diving Unlimited with Michael Rutzen, involving the design of moorings for acoustic loggers, developing marine-themed educational material with De Hoop Collection, and with pilot Evan Austin who donated all his photos for photo-identification of southern right whales – comprising several years’ worth of useful material.
Besides the research side of the project, it is a high priority to educate the local community. The project was represented at different venues: The annual Whale Festival in Hermanus, Hope Spot launch in Hermanus with Dr Sylvia Earle, and public talks by the project leader at De Hoop Nature Reserve, Pearly Beach and Stanford Bird Fair. International and local university students with particular interest in cetacean research were welcomed as volunteers. Spending typically 2-6 months, they receive training in the scientific methods within the field of marine mammology.
2015 will be spent finalising the analysis of the data, writing up articles and the thesis, due to be submitted in September.
A new collaboration has been established with the company Seiche Limited, which specialise in monitoring underwater sounds, the development of equipment and training of marine mammal observers.
In September 2014, during the peak season for southern right whales, a team from Seiche came to De Kelders, Walker Bay, to test a floating acoustic buoy, underwater moored hydrophones (with a feed to a land-based station), and heat-sensitive cameras.
The tests were very successful and, in particular, the bottom-moored hydrophone provided information on the acoustic sounds production related to the behaviour of southern right whales present in the area.
Due to this success, Seiche donated the moored hydrophone system to the project for the rest of the whale season.
Gradually as the calves are getting larger (both longer and thicker) – their mothers are getting thinner. The mothers do not feed while they are here off the South African coast, but sustain themselves from their thick layer of blubber, which they build up while feeding in the Sub-Antarctic waters from January to May.
The southern right whale mother and calf pairs are ruling the bay at the moment! Some days we have had more than 30 pairs in the bay. They mainly spend time travelling slowly along kelp beds, relaxed, rolling, and logging in the same place. The calves are by far the most active and often breach and play around the mother. Maria has been tracking the detailed behaviour of the mother and calves, and they are spending lots of time travelling, milling, or being submerged. We have had at least five brindle calves frequenting the area. Since most of them have very distinct markings we were able to tell them apart.
We encountered dolphins on two occasions. A small group of indo-pacific humpback dolphins had a feast where they were so active that the fish were thrown into the air. Also, the indo-pacific bottlenose dolphins visited the bay and spent almost two hours surfing the waves.
The annual aerial survey of southern right whales off the South African coasts also took place in October. It was the 34th time that the Whale Unit from the Mammal Research Institute (MRI) of Pretoria have conducted the survey. Meredith Thornton, Ken Findley and Andre´ du Randt from MRI, were responsible for carrying out the survey this year. They started on the 8th of October.The survey team takes photos of the callosity (skin growth) patterns of the mothers; each whale has a unique pattern and can be identified by this. Later the pictures will be analysed and matched to the current catalogue.
Due to the harsh weather conditions the aerial survey was only finished on the 4th of November. Normally it is completed before the end of October and takes a maximum of two weeks.
The team is looking forward to the summer and calmer weather conditions. Day by day we are seeing more and more tortoises on the roads when driving to Pearly Beach – a sure sign of summer approaching.
The theodolite tracking is running like a well-oiled machine and the team has seen sightings of humpback whales almost every week. These animals seem to have changed focus from migration to social behaviour. They spend much more time breaching and their pattern is not as predictable as the migrating humpback whales in July and August.
A new addition has permanently joined the tracking station at the water tower. A bright green snake has moved in on the rail! The team put it there to prevent the local white necked crows from ‘decorating’ the top of the tower and attracting countless tiny flies.
September was the month where the southern right whale mother-calf pairs moved into the bay while the mating groups decreased. Maria Johansen joined the team at the beginning of the month. She is here until the beginning of December conducting a small study of the interaction of the mother and calf pairs. We welcome Maria who is a dedicated biology student from the University of Copenhagen.September marks the yearly event of the Whale Festival in Hermanus! For the team it involved public talks, manning the Dyer Island Conservation Trust stand, helping out at the children’s tent with colouring books, and exploring the festivals many attractions. The atmosphere at the festival was amazing this year, even with less than ideal weather on the Friday and Saturday – and people came from far away to celebrate the whales.
Another notable event was the four day International Aquarium Conference hosted by The Two Oceans Aquarium in Cape Town. As part of the conference the delegates went out with either Slashfin for a shark cage dive or a whale watching trip with the Whale Whisperer.
Returning to the project, the team has been spending dedicated time assessing the locations and mooring of the acoustic loggers, and we are now just waiting for consecutive calm weather days to progress further.
Perhaps the highlight of the month, however, was a flight with African Wings! A completely different and truly astonishing way to view the whales in the bay! Evan Austin took us flying for one hour allowing us to witness Dyer Island, Slashfin at sea, Kleinbaai harbour, Gansbaai and the unforgettable Walker Bay with all the whales. It is the best way to experience and understand the behaviour of the mating groups, as well as the mother and calves. Evans´ four seater Cessna 175 is ideal for the task since it does not scare the whales, and from 1000 feet we could still see every detail on the whales. Evan is an extraordinary pilot, friendly and professional, with an infectious passion for the area and the animals.
What is that? Is it splashes from a boat? Is it the wind coming in? –NO! It is hundreds of common dolphins swimming into the bay! From the top of the water tower we can see up to 15km on a good day with clear visibility. On this unique day in August we spotted a pod of common dolphins 11 km away. The pod stretched more than one km. We alerted the whale watching boat and directed them to the sighting. They called us back shortly afterwards and reported that besides the dolphins they saw seven -eight killer whales hunting the dolphins. This is a known behaviour along South African coasts, but has never been observed in the Dyer Island area. In fact this is only the second time that killer whales have been sighted from the whale watching boat since we started in 2000. So the excitement level was high and the DVD was watched over and over again in the offices in the afternoon.
The killer whales did not catch any dolphins while the boat was there, and the pod only stayed in the area for 40 minutes. Our research boat Lwazi did try to catch up with the pod, but the dolphins had left the area and the tracking team on the tower had lost sight of them before the boat was even close to the area in which the pod was sighted by the Whale Whisperer.
Only four days after, a similar (or most likely the same) large pod of common dolphins returned to the area – this time the dolphins were feeding on sardines together with at least three Bryde´s whales. It was a spectacular sight to see these huge baleen whales shooting out of the water – in a powerful launch feed, surrounded by diving gannets and jumping common dolphins. A local sardine run! These events are rare in our area!
Southern right whales are a common sight here in August, and it has been the month where the surface active groups (SAG) returned and increased in numbers. At the beginning of the month we had four to five groups with max three individuals – reaching five to six groups with up to seven individuals at the end of the month. So more and more animals are moving in. SAG are normally related to courtship and mating behaviour.
Gradually, as we reached the end of August, we saw fewer and fewer humpback whales; by now most of them should have reached the shoreline of the Eastern Cape and Mozambique.Anna Skinnars and Emma Fitzmaurice Vestergaard are still the backbones of the volunteer team and they make an amazing difference – conducting the theodolite tracking, entering data, analysing data, and basically pitching in whenever a helping hand is needed. They ROCK!
They also have special tasks, and Emma has been converting and filtering out all the effort data from the whale watching boat. Anna has prepared the data for the MammalMap and based on the whale watching boat data and the work of the whale research team – DICT are the first organization in Africa so submit observation data of marine mammals. See www.mammalmap.adu.org.za
A new backbone of the project is “Sir. Humphrey”. He is very reliable, adventurous, and safe addition to the team – our Land Rover Discovery TDI is making the drive to the theodolite tracking station smooth and future strandings of marine mammals will become easy accessible.
At the beginning of the month Katja went to Denmark for 10 days to work at her cooperation organisation “Statens Serum Institut”. Lots of hours were put into fundraising, writing articles, and testing the two new underwater sound stations. Doctor Michael Christiansen is an extraordinary support and help – thank you Michael.
Back in Kleinbaai the listening stations are now about to be moored at the sea floor, but with the harsh winter weather and never ending cold fronts pushing in, it has not been feasible to complete the mission yet. September is the month of the revolutionary addition of underwater sound recordings!
Breaching humpback whales, feeding groups of Indo-pacific bottlenose dolphins and southern right whales returning for the season –These are some of the amazing sightings the theodolite tracking team and the guests on the Whale Whisperer have been experiencing in June.
The theodolite tracking has been running smooth even though the winter is over us and the rough wind and rain have prevented the team to go out on several occasions –but the team is tough and in the cold mornings with frost on the lawn they wrap up in gear as if they were going to Marion Island! Since the days are shorter at the moment the team track throughout the hours of daylight if the weather permits it.
Anita Hansen (Denmark) and Anna Skinnars (Sweden) have been the dedicated volunteers in June. They have been tracking many humpback whales migrating towards their mating and nursing grounds. From the tracking data it might be possible to establish if the humpback whales are heading towards the west coast or to the east coast.
The southern right whales are back! Finally after many months where we have been longing for the sound and vision of the gentle giants. At the end of June we saw them almost on every theodolite tracking day. The amount of animals we have seen and the consistency is very similar to what is normally observed in July, so they seem to be back early and in high numbers.
After six weeks unfortunately Anita had to return to Scandinavia for other adventures, but she will return next year –she learned more about fieldwork and managing projects from being in South Africa than she ever did at the university.
Anna will stay at least until December as she says “I have to experience the wonderful South African summer after surviving the never ending cold winter!”
Besides Anna, Peet Botas (South Africa) arrived in the beginning of July. Peet is spending his winter holiday helping out as a very dedicated volunteer. They are both being trained in theodolite tracking, analysing ID-pictures of dolphins and handling large amounts of data. Both volunteers have also been out at sea with our whale watching boat “The Whale Whisperer” where they encountered the southern right whales up close. Anna said when they returned “Gosh -The size of these animals! One thing is to see them from the shore, but being next to them on the boat blows your mind!”A trip with The Whale Whisperer is an experience for lifetime!
The theodolite tracking is going very well, and we have seen the first southern right whales, so it seems like we are going to be super busy this season! We have a few volunteers coming in to help us which will be just in time.
In September, a student will be doing a dedicated project looking further into the behaviour of whale mothers and calves. For example, she will monitor the average distance between them, which one initiates contact, and how much time they spend socialising with other mother-calf pairs. This is a spin-off from my presentation at the Danish Marine Mammal Conference which I attended in May.
Just two weeks ago I also presented at the African Marine Mammal Symposium, which we hosted at the Great White House. Around 50 participants from all over Africa were present, mainly South Africans. I presented the whale watching data, which was a huge success.
I am finalising the two first articles based on the whale-watching data at the moment. It has provided us with some very interesting trends – for example, it is clear now that the southern right whales arrive in the area in June and can be seen to have done so since 2003, as presented in our research.