Beach survey to Cape Cross

by Michelle Wcisel

“There is a sufficiency in the world for man's need but not for man's greed.” ~Mohandas K. Gandhi (Warning: Some readers may find the pictures in this blog post disturbing).

Yesterday, we took a shore-side drive to Cape Cross to scope out potential launch sites with the hope of expanding our coverage of the coast to the north. However the tone of the trip quickly changed to a beach scavenging expedition as we learned the truth behind the “Skeleton Coast.” We found countless Cape fur seal skeletons, a few leatherback turtle carapaces that had been bleached in the sun, dozens of stranded shore birds, and four spotted gully sharks. The majority of the carcases were there due to natural causes, but every shark we found had been hooked and carelessly cut from the line.

When your career is in a biological science, especially one that is based in field research, you are exposed to life and death daily. You come to understand that cycle as an integral piece of a healthy ecosystem, and seeing a natural death of an animal changes from a mournful moment to solemn recognition of a bigger process in action. But, when you come upon an animal that has had its life taken by a hook, or a piece of line that cuts through its body, or a plastic bag lodged in its throat, you never stop feeling infuriated.

The first spotted gully shark had been killed within the hour we found it. It was a female, her gills were bright red and her body was still cold to the touch (cold because she had just been in the cool water, if she had been on the beach for awhile, her skin would have been hot from the sun – like the other three sharks we found). The line had cut through the corner of her jaw and it was obvious she had given the fishermen a “lekker fight” since the tension of the line had worked a massive wound into the side of her face. Out of curiosity, we collected her to do a full autopsy to further determine her cause of death, but were not expecting to find that the majority of this 1.55m shark’s body cavity was uterus. She was carrying 8 pups, 4 female and 4 male, all around 33cm in length. We eventually found the hook, which had punctured through her oesophagus, worked into her pericardial cavity, and pierced the left side of her heart. It is impossible to tell which of these injuries killed her first.

A mass loss of life like this feels overwhelming when you extrapolate it to all the world’s beaches, especially when you consider how this pales in significance to some of the horrors happening in the offshore fishing fleets. It is legal in Namibia to catch spotted gully sharks and they are classified on one of the lowest ranks by the IUCN Red data list as “near threatened”. However, it is important to recognize this type of blatant waste in order to inspire more research, more students, and further grasp the sense of urgency our oceans are silently suffering. If nothing else, the death of those sharks inspired a blog, maybe a few conversations, and perhaps some of you readers got to see images that are unfortunately all too commonplace to us in marine biology.

Welcome to summer season 2010! After a long drive/bus trip from our starting points of Johannesburg and Cape Town, we started the season off in Lüderitz to pick up and dust off Nanuuq. After 2 days of howling wind we took advantage of a lull in the weather to get in one good sea day. Lüderitz is after all, the “Heaviside’s capital of the world”. The dolphins in Guano Bay started the day being somewhat evasive, preferring the company of the kelp to that of the boat. However, they became a lot more amenable as the day wore on and we had many boat friendly groups, including a mother calf pair (will try to put up a video link when we get a better internet connection). This was out first ‘photo ID’ day in Lüderitz and it was great to see so many well marked animals – we’ll begin developing a catalogue for the area in the near future, which will start to feed into future abundance estimates for the region. Alas, high winds and a dropping tide put an early end to our day, although we did get a chance to check on the C-POD in Shearwater Bay and it hasn’t moved an inch since it was deployed by Ruth in December!

Two days of tar road driving later (we didn’t want to chance the boat and trailer on the dirt roads in this rainy summer season) we arrived back in Walvis Bay. During our first day out at sea we didn’t get too many good photos with the dolphins being evasive and the weather cloudy. However, we were excited to discover that two of the marked animals we photographed were Heaviside’s known from the 2008 catalogue! This was a great way to kick off the season and our first confirmed evidence on long term residency of Heaviside's dolphins in Namibia (the general behaviour of the animals at Walvis Bay is so different to those in South Africa that there was no certainty of this characteristic either). Later in the week, “Dave” the bottlenose joined us with three of his friends for a romp around the shipping channels. “Dave” is probably the most boat friendly and photogenic of the bottlenose dolphins in Walvis Bay and does his best to hog the limelight during encounters with him.

Neels Dreyer informed us of a stranded Heaviside’s dolphin in Donkey Bay (on the outside of the Point) and we were able to collect it the next day. It was a small, juvenile male only just over a metre long – the plates in the skull weren’t even fused yet. It was unfortunately too desiccated after a few days on the beach in the Namibian sun to allow for the collection of many samples, but we kept the skull which will be passed on to the museum in due course and got a few basic measurements.

The days have been characteristically cool with bright sunshine on the dunes but clouds over the sea. With any luck, we’ll run into the rumored humpback whale sometime soon…

With a little help from our friends..

A nice bit of news for the project. The new boat Nanuuq has been without a working depth sounder or GPS since we got her last year, which obviously makes navigating in the mist rather challenging. Knowing the depth is also of great importance to us so we know how much rope to put on the hydrophone moorings and when we're over reefs.

Even more importantly, from a scientific point of view we can use the depth and temperature data generated by the fish-finder as part of the environmental data we collect at dolphin sightings to help build up a model of their habitat use patterns.

Last year I asked Garmin South Africa (run by Avnic Trading locally) if they would sponsor us a small GPS / Fishfinder unit for the boat, and they've agreed! I'm currently sitting with the new 'toy' in my hands, a 420S and will be fitting it to the boat as soon as we get to Namibia at the end of the month.

A big thank you to Fraser McHenry at Garmin South Africa

Rescue of a rare whale

By Ruth Leeney

On the 6th of January, a pygmy right whale (Caperea marginata) stranded just south of the pumpstation in Walvis Bay. The whale was a 3.5m youngster. Members of the Walvis Bay Strandings Network, including John Paterson and Naude Dreyer, quickly made their way to the scene and had a easy time getting it back into the water, although the whale did at first seem very disoriented and headed straight back to the beach four times before finally swimming out into the bay. This kind of behaviour is not uncommon in stranded cetaceans, and reinforces the importance of monitoring the animal after it has been refloated!


The pygmy right whale is one of the least-known whales in the world. It is very rarely seen at sea, and is mostly known from the few stranded specimens which have been examined by scientists, post-mortem. They grow up to about 6 m in length. Pygmy right whales are so-named because the shape of their head resembles that of a true right whale, but they are not closely related. Pygmy right whales are found only in temperate waters of the southern hemisphere. Sightings occur year-round in Tasmania, and seasonally along the coasts of South Australia, New Zealand, South Africa, the Falkland Islands, and some areas of Antarctica.


We're really proud of the Walvis Bay Strandings Network, for acting quickly and efficiently in this matter and with a number of other recent strandings. Their continued interest and voluntary efforts ensure that we can get rare creatures such as this pygmy right whale back into their natural habitat, and perhaps learn something about the in the process.

Lüderitz, 17-20 December

By Ruth Leeney

Having deployed 2 C-PODs in the Lüderitz area back in August as well, I had hoped to get down to the south, retrieve the units, download their data and get them back out in the water as part of this trip. As my schedule became more restricted, Jean-Paul Roux at the Lüderitz offices of the Ministry of Fisheries and Marine Resources was invaluable in helping out. He organised the retrieval of both units, to have them waiting on land for me when I arrived. Unfortunately, only the C-POD with the surface marker buoy, deployed in Shearwater Bay, was retrieved, so hopefully, efforts in the new year to grapple for the Guano Bay POD will be successful. For now, at least, the first ever acoustic monitoring dataset for this region has been collected - the C-POD logged over 100 days in an area known to be used by small groups of Heaviside's dolphins, and plenty of detections are evident in the data.
The Shearwater Bay C-POD was re-deplyed in the same spot on the 19th of December and will continue to collect habitat use data in this area. I hope to see some seasonal patterns in these data start to emerge, as well as the interesting diel (day-night) patterns already evident!
Many thanks to Heiko and Stefan Metzger on Zeepard for their assistance in the field, and for the 'lekker' place to stay, and to Jean-Paul for his ongoing involvement with this project.

Keeping the acoustic monitoring 'clicking' over....

By Ruth Leeney

December in Walvis Bay. Turns out the sun actually shines here sometimes! I have come back for a short visit, to check up on the C-PODs Simon and I deployed, with the help of Johann from Levo Tours, at the end of August. It has been just over 3 months, so the batteries are reaching the end of their running time, and after that long in the often-wild waters of the Namibian coastline, I thought it wise to check that the moorings were also still in place and were holding up well against the storms!

The project's 2 C-PODs at Pelican Point were retrieved last week. After we received a report that the surface marker buoy from this mooring had gone missing (thanks to all our local friends who were on watch in our absence!), a team from Namib Diving went out to the location and grappled for the gear, in and around the deployment location. The waters at Pelican Point have almost zero visibility and are thus not diver-friendly, so we really appreciate the time and effort they put into finding this gear for us. Three months' worth of data were downloaded from each C-POD and at first look, there are plenty of Heaviside's dolphin detections throughout that time period! More details will follow on our findings from this, our first long(ish)-term acoustic data set. Meanwhile, the PODs were spruced up a bit (in the rich waters of Walvis Bay, 3 months is ample time for an assortment of encrusting organisms to make any unsuspecting POD their home), given new batteries and re-set for more data collection, and with the help of Kurt and Darius from Namib diving, I redeployed them at Pelican Point today, whilst numerous Heaviside's dolphins surfaced a few hundred metres away. We also stopped at Aphrodite Beach, to retrieve the third C-POD, which will be re-deployed shortly. A solitary Heaviside's dolphin, about 500 m west of the Aphrodite Beach, was perhaps the first of this species that I have seen in this area, perhaps mirroring the more dispersed pattern of this species in summer, observed by Simon last year. A huge thank you to Gert Le Roux and the staff at Namib Diving for helping me get this done in a short time window.

On another note, the dusky dolphin which live-stranded in Walvis Bay on the 3rd of December generated a bit of press for the Walvis Bay Strandings Network which we have been working to re-invigorate over the past 18 months. John Paterson oversaw the successful refloatation of this animal and by passing the story on to the Namib Times, generated some good press for the Strandings Network and helped to spread the word amongst local people about what action to take, and who to contact, in such a situation.

Interns

From 2010 onwards we will be accepting interns as part of the Namibian Dolphin Project.

Interns will take part in all project activities and learn a whole host of field and data management skills. Having extra hands to help out will allow us to do more things and get more days at sea and include some extra dimensions to our field research.

For more information on the programme, please see:
www.oceans-research.com

If you're a Namibian biology student and interested in working on the project, please contact me directly to talk about internship and potential student projects.
s_elwen AT yahoo . com