Katie has been fighting some sort of disease for the past 2 weeks. Its progression went like this: first, a little diarrhea; then a runny nose; at its worst, a night of restless fever, followed by 3 evenings when she vomited immediately after dinner. One of these nights was also restless, including teeth-grinding. For about the last week, she has continued to have a hacking cough and banana slugs up her nose. Mucus is now turning green and crusty, a sign that the immune system has kicked in. Meanwhile, during the worst of this, I was simultaneously trying to complete three curriculum submissions for the department – this meant 1-on-1 meetings and advisory committee meetings most of each day, while writing and editing at night. Only it was particularly difficult for me to do any work at night, because I would help Katie get to sleep (conservatively a 20-minute process) and 5 minutes after I got back on my computer, she would be calling for me again. Well, it’s clear I wore myself down, so by the curriculum deadline (Apr 25), my nose was a torrent of phlegm and my patience worn down to a thin veneer. Alan was also grumpy: although he was least affected by disease (just one day of self-described incredible gaseous eruptions), he was fielding calls from the coast about how much we were needed there, plus running a lot of errands and forgetting to eat.
The good news/bad news was that the Friday afternoon meeting for administrative feedback on the curriculum submissions was canceled at the last minute. Instead, we left immediately for the coast. On the 4-hour drive, my scratchy throat transformed into earaches so intense that I couldn’t hear, totally precluding my normal Katie-entertainment duties. Then Katie said her ears were hurting too. I was ready to go to the emergency room at the Swakopmund hospital, but Alan correctly diagnosed our ills: My stuffy head had dis-equilibrated from the pressure differential between 5000 ft and sea level, cured in a matter of minutes after a dose of Panado (not available in the US, but Alan had heard of it before). Katie was simply trying to be a participant in everything and still just had a runny nose (well, she had vomited earlier…). Definitely the nadir of our trip!
A longer-term health concern has been Alan’s sore foot, probably plantar fasciatis, although not quite in same spot as in years past. It’s been exacerbated by several long barefoot walks on the beach, plus his first choice for shoes to be worn in the water – so many nylon straps across the top that they caught rocks top and bottom, causing blisters and sores as well. A couple of weeks ago Alan succumbed to family peer pressure and went searching for size 13 Crocs – Katie and I both wear these almost constantly, in and out of the water, and we’ve found them extraordinarily comfortable and functional. Fortunately, Alan was able to find a manly black pair of Crocs that fit him – shoes are a big deal in Namibia, and there were plenty of stores to check, although we still feel lucky that there were actually several styles in his size – and foot complaints have eased. Of course, Alan had to eliminate all the Crocs logos by drawing over them with a black sharpie!
Friday, May 2, 2008
Katie update
Anyone who has tried to talk with Katie over the phone, or who meets her for the first time, would never believe how much she talks with her parents and friends. She tells extended stories about going to the post office, or about the lives of cormorants (catching fish, feeding their babies, going to sleep), or about going to school with Abby and Teddy. Sometimes she tells us about how she can shoot birds, or about how someone shot back at her but she didn’t die: This shooting legacy is either from playing with Fulbright kids who are older boys, or from my training one day at the beach when Alan was giving me a hard time for pretending beach wrack was different family members – what are the options for playing on the beach? Interpersonal relationships among mussel shells and lobster legs, building towers out of rocks, digging holes, or shooting with kelp stipes! Actually, I have to say that learning how to shoot seems incrementally better than learning about barbies, which has been Katie’s experience with older girls: I’ve run interference to encourage barbies to go on sailing trips, instead of repetitively going on dates and getting married.
Katie does finally have her own doll, so she no longer needs to wrap up a hairbrush in a washcloth and rock it to sleep. She selected Abalone from among the hand-made doll options at the large craft shop in Windhoek – Abalone is wonderfully adventurous (although entirely cloth, so doesn’t go to the beach) and hardly ever cries or complains!
Once or twice a day, we get out the lightweight orange ball and play soccer (here football) on a sandy spot near the hatchery. Katie’s ball-handling skills have definitely improved: she can give the ball quite a boot, although only in the direction that she’s running, which means I often have to run it down before it enters the Salt Co canal or goes under the boundary fence. When the wind picks up, soccer is particularly challenging, because the wind drives the ball almost faster than I can run! Katie has also figured out the basics of catching a ball in her arms.
We spend a lot of time at the beach looking for tracks and skeletons. She is learning how to tell jackal from hyena tracks (hyenas have very large front feet; jackals tend to place their back feet exactly in the front tracks) and also tell their kills apart. She knows that a dead cormorant with a hole in its belly was killed by a jackal, whereas hyenas tend to dismember the entire bird. One particularly tragic kill included a cormorant let still tangled in fishing line and wire… and with older bones indicating that this gear had been ghost-fishing for some time. Clearly the extra load weighed down the bird and made it an easy target for the hyena. But, of course, as ecologists, we talk with Katie about how predators need to eat, so it’s sad for the cormorant but necessary for the hyena.
Katie is not a huge fan of hyenas – they are on her “scary animal” list along with lions, crocodiles, and hippos. I think this is because Alan responds to her screaming by telling her she should be quiet or she’ll call the hyenas!
Alan has been through heroics to acquire some basic research equipment that we take for granted in the US, specifically iButtons, which log temperature remotely, and a YSI dissolved oxygen, temperature, and salinity meter. He is still working to acquire material for plankton nets. In retrospect, of course, we could have brought these things with us, but we really had no idea just how large a role anoxia plays in Namibia’s marine environment, nor that we would be working in a reverse estuary – the salt ponds just keep getting saltier! I mention this in the context of Katie because we now have temperature records for a variety of locations around the Salt Co, and the records are dramatic – up to 10C degree swings daily, probably as a response to solar heating of shallow water in the day and black-body radiation to a clear sky at night. Katie happily paddled around in shallow 30C water, just where the canal exits into the oyster pond and the water is warmest in the afternoon – it was just the right depth for her to support her body on her hands, and to enjoy the soft sinking sensation of anoxic sediment on the bottom (Apr 5)!
Katie has just exceeded the 20-freckle threshold – and yes, we are keeping her in sunscreen! She is in the phase of perpetual “Why?” And she has begun to add “eee” on the end of words. Sleep-ie, Bike-ie, Juice-ie. No one around her talks like this, as far as we know, so where does this come from?
On 2 occasions in Windhoek, our time there has overlapped with a lunchtime dance in the parking lot. A group of Oshivambo women occasionally gathers, sometimes with a single drum, but also just with clapping and their voices, in a circle. One by one or in pairs, the women dance into the center. The rhythms have been too complicated for me to pick up yet (let alone the words), but I have learned that the steps they use are very particular for each song, not free-form dance. The style involves flat-footed stomping, skipping, jumping. Katie has been transfixed by the music and dancing, but unwilling to join in, even though the women say that they began learning these songs when they were Katie’s age.
Katie does finally have her own doll, so she no longer needs to wrap up a hairbrush in a washcloth and rock it to sleep. She selected Abalone from among the hand-made doll options at the large craft shop in Windhoek – Abalone is wonderfully adventurous (although entirely cloth, so doesn’t go to the beach) and hardly ever cries or complains!
Once or twice a day, we get out the lightweight orange ball and play soccer (here football) on a sandy spot near the hatchery. Katie’s ball-handling skills have definitely improved: she can give the ball quite a boot, although only in the direction that she’s running, which means I often have to run it down before it enters the Salt Co canal or goes under the boundary fence. When the wind picks up, soccer is particularly challenging, because the wind drives the ball almost faster than I can run! Katie has also figured out the basics of catching a ball in her arms.
We spend a lot of time at the beach looking for tracks and skeletons. She is learning how to tell jackal from hyena tracks (hyenas have very large front feet; jackals tend to place their back feet exactly in the front tracks) and also tell their kills apart. She knows that a dead cormorant with a hole in its belly was killed by a jackal, whereas hyenas tend to dismember the entire bird. One particularly tragic kill included a cormorant let still tangled in fishing line and wire… and with older bones indicating that this gear had been ghost-fishing for some time. Clearly the extra load weighed down the bird and made it an easy target for the hyena. But, of course, as ecologists, we talk with Katie about how predators need to eat, so it’s sad for the cormorant but necessary for the hyena.
Katie is not a huge fan of hyenas – they are on her “scary animal” list along with lions, crocodiles, and hippos. I think this is because Alan responds to her screaming by telling her she should be quiet or she’ll call the hyenas!
Alan has been through heroics to acquire some basic research equipment that we take for granted in the US, specifically iButtons, which log temperature remotely, and a YSI dissolved oxygen, temperature, and salinity meter. He is still working to acquire material for plankton nets. In retrospect, of course, we could have brought these things with us, but we really had no idea just how large a role anoxia plays in Namibia’s marine environment, nor that we would be working in a reverse estuary – the salt ponds just keep getting saltier! I mention this in the context of Katie because we now have temperature records for a variety of locations around the Salt Co, and the records are dramatic – up to 10C degree swings daily, probably as a response to solar heating of shallow water in the day and black-body radiation to a clear sky at night. Katie happily paddled around in shallow 30C water, just where the canal exits into the oyster pond and the water is warmest in the afternoon – it was just the right depth for her to support her body on her hands, and to enjoy the soft sinking sensation of anoxic sediment on the bottom (Apr 5)!
Katie has just exceeded the 20-freckle threshold – and yes, we are keeping her in sunscreen! She is in the phase of perpetual “Why?” And she has begun to add “eee” on the end of words. Sleep-ie, Bike-ie, Juice-ie. No one around her talks like this, as far as we know, so where does this come from?
On 2 occasions in Windhoek, our time there has overlapped with a lunchtime dance in the parking lot. A group of Oshivambo women occasionally gathers, sometimes with a single drum, but also just with clapping and their voices, in a circle. One by one or in pairs, the women dance into the center. The rhythms have been too complicated for me to pick up yet (let alone the words), but I have learned that the steps they use are very particular for each song, not free-form dance. The style involves flat-footed stomping, skipping, jumping. Katie has been transfixed by the music and dancing, but unwilling to join in, even though the women say that they began learning these songs when they were Katie’s age.
Mercy’s fish cakes and further adventures with food in Namibia
We have discovered what are quite likely the best fish cakes on the planet, served at Mercy’s take-away and catering near the northern road out of Swakopmund. It’s a difficult decision whether to have potato salad or French fries (here “chips”) on the side, as both are exceptionally tasty. To paraphrase Dr. Seuss from the Sleep Book, “Mercy’s is grand for having a bite/ if you happen to be there with your appetite.” Mercy herself reports that she will look for a location closer to town, because most of the people walking by cannot afford to eat out. This was yet another reminder of the economic gap between visiting Americans and most Namibians, as we find it quite incredible that we can feed the two-and-a-half of us for about $US8.
We have been learning more southern African terms for food: Pawpaws are papayas, Peppadew is a slightly spicy red pepper, Naartjies are small Satsuma oranges (it’s citrus season here), Mahango is millet, a staple in parts of the north that we have not yet eaten, and maize of course is corn (we have had mixed experiences with fresh sweet corn, but continue to try it because the best ears are really good – again, it’s the late-summer/ fall season for it). Rusks are like biscotti, available in a variety of flavors (buttermilk, muesli) and chocolate-dipped for holidays. According to the Ouma Rusks package, they are “a unique crunchy snack,… a truly South African icon, sought after in many countries around the world. The ideal treat, they can be served any time of the day or night and are equally delicious with tea or coffee.” After passing by entire aisles of rusks in the grocery stores for the past several months, we made an impulse buy to try them… and we’ll buy more! Katie is in a phase where she loves to dip food, and JR (as mentioned before) is happy with any excuse to have more 5 Roses tea. Alan was excited to learn that the basic rusk recipe includes some coconut!
At least one mystery still remains with respect to Namibian food: Monkey gland sauce!
We have been learning more southern African terms for food: Pawpaws are papayas, Peppadew is a slightly spicy red pepper, Naartjies are small Satsuma oranges (it’s citrus season here), Mahango is millet, a staple in parts of the north that we have not yet eaten, and maize of course is corn (we have had mixed experiences with fresh sweet corn, but continue to try it because the best ears are really good – again, it’s the late-summer/ fall season for it). Rusks are like biscotti, available in a variety of flavors (buttermilk, muesli) and chocolate-dipped for holidays. According to the Ouma Rusks package, they are “a unique crunchy snack,… a truly South African icon, sought after in many countries around the world. The ideal treat, they can be served any time of the day or night and are equally delicious with tea or coffee.” After passing by entire aisles of rusks in the grocery stores for the past several months, we made an impulse buy to try them… and we’ll buy more! Katie is in a phase where she loves to dip food, and JR (as mentioned before) is happy with any excuse to have more 5 Roses tea. Alan was excited to learn that the basic rusk recipe includes some coconut!
At least one mystery still remains with respect to Namibian food: Monkey gland sauce!
April marine observations
We continue to have a superb time living on the beach and feeling a part of each day’s natural history. In the morning, we can tell which way the wind is blowing based on the location of the steady stream of cormorants traveling from guano platform to ocean. A million of them in a long line, they tend to fly into the wind. We have not yet determined the cues that cause them, on some days, to gather as a huge black blanket on the beach before heading out to sea. One day last week, we witnessed semelparous reproduction: A particular type of flying insect has been accumulating in ever greater numbers – Mr Klein calls them midges, and they are mosquito-sized, with no bite or sting, but a very dark lipid stain when smushed, highly attracted to light. One morning we found thousands of them stuck to the windows of Hotel California, interspersed with spiral egg cases about a cm long, surrounded in gelatinous mucus. By the end of the day, it was clear the insects had made the wrong choice for egg-laying: midges and mucus had all dried up. And we haven’t had to be nearly as vigilant about closing doors before turning on lights since then. Seasonal changes are also evident in the colors on the beach at low tide. When we arrived, the intertidal zone was red with Gracilariopsis (this identification tentative, but coincides with the monograph on Namibian algae published in the 90s). Now much of this has been reduced to perennial holdfasts, with a few female plants bumpy with carposporangia, and the intertidal zone is green with a flush of ulvoids. It’s somewhat embarrassing to admit that we have not yet determined the identity of the less than half dozen species of terrestrial plants living alongside us in the coastal desert. But, we know a bit about their natural history: Many of them accumulate mounds of wind-blown sand, where gerbils and ants then tunnel for security (and presumably food). Since our arrival here, many of these plants have been subtly flowering, more so on the down-wind (N) side. We can also see the dried remnants of annual plants that apparently completed their whole life cycle in the spring before we arrived.
We know that the tide has dropped, leaving dislodged mussels stranded on the beach, when we see the gulls flying up, dropping a large Perna, then following it to the ground to see if it has broken. The introduced clam in the salt pond, Ruditapes decussata (from the Channel Islands), was recently decimated by birds – hundreds of large shells lay broken around along the road. Alan has not been particularly impressed by gulls with such dysfunctional bills that they can’t even get into a dislodged bivalve, but Mr Klein says they’re actually quite smart: along areas of the coast with no hard substrate for dropping and cracking bivalves, they simply place Donax clams on the sand dunes until they gape from the heat and desiccation. While the gulls go for the large Perna mussels, turnstones seem to love the small Semimytilus. These have been washing up in clumps on the beach recently, probably dislodged by waves as the mussel beds have become thick, no longer attached to rock but to an accumulated layer of sand of several cm. It’s easy to see the pattern of patches within the mussel beds at low tide, and we suspect that, given the fast growth and small size of this mussel species, it would be possible to watch patch dynamics over months, rather than the years required by Paine and Levin on the Washington coast!
On the subject of mussels, I spent one illuminating afternoon looking for boring organisms in Perna. The idea came from our desire to begin testing top-down control of Polydora in the salt pond: what really caused the polychaete to essentially disappear in 2004? Was it isopods? Nemerteans? Since we have found so few Polydora in oyster shells – an infection rate of about 2% - we wondered if we could use spionids in mussel shells as a surrogate, then test to see if either isopods or nemerteans caused mortality. We know from walking along the beach that the wrack is full of bored mussels (you know, riddled with holes. You can’t be the other kind of bored when you’re dead!).
So, on a fair to middling low tide, JR walked down to the rocks by the Salt works, dressed in my normal Namibian field gear: bathing suit, wrap-around skirt, Crocs, wide-brimmed hat, long sleeves (it’s either that or a lot of sunscreen). The first thing I noticed was that the upper limit of Perna was just barely above the waves, which is not unusual given the rather small tidal amplitude, just a bit over 1 m. The second thing I noticed was that Perna at its upper limit is not bored, but instead seems to be sand-scoured except at its growing edge, sometimes to the point of having a concave outer shell surface. Finally, I found a few large mussels rolling around in a tidepool that had apparently been dislodged from lower down: they were covered with erect bryozoan epiphytes, red tufts of algae, and obviously bored. I put these in a bit of water in my bucket and carried them off hopefully to the ‘scopes at the hatchery, then spent the next 3 hours noticing a third thing: Most of the eroded burrows in Perna are full of phoronids!
For those of you not completely versed in marine biodiversity, I’ll simply state that Polydora is a polychaete annelid, a segmented worm, in a family characterized by the presence of two long palps on the head. I think I saw 2 long palps once in 15 shells, but was unable to extract any more – and in any case it may not even have been a boring spionid, but rather one that builds its tube in sediment. In contrast, phoronids are in an entirely separate invertebrate phylum. They are soft-bodied, unsegmented worms, with a horseshoe-shaped ring of tentacles on their head – this headdress made them quite unmistakable as soon as I found a shell that still contained live individuals. But then the next question: Did the phoronids make the tubes, or just occupy someone else’s burrow? Our satellite internet access at the beach came in handy once again, as I was able to search on “shell-boring phoronid” and learn that one of the 17 species of phoronids IN THE WORLD – and the smallest one, at that – makes burrows in mollusc shells. All the evidence points towards Namibian subtidal Perna perna full of Phoronis ovalis. It has been reported from a different Perna species in New Zealand, as well as from abalone in Chile. As far as we can tell from beach wrack, only one of the 4 mussel species on this coast hosts Phoronis ovalis, and we gather they are not a problem in aquaculture here. I guess that is good news for the oyster growers, but it puts another hold on our quest to discover the mystery of the missing Polydora.
Another quest we have set ourselves is a better understanding of Venerupis corrugatus, the native littleneck or steamer clam on this coast. We heard early on that this clam was ubiquitous, and indeed we’ve found it in mussel beds, intermixed with intertidal polychaetes, and washed up next to the Walvis Bay yacht club. Most impressively, we saw tiny (1-2 mm) individuals at incredible densities fouling the oyster culture gear in Walvis Bay, apparently a recent recruitment event at exactly the same time that so many oysters were dying in March! Two weeks later, the oyster gear coming out of Walvis Bay had clams around a cm long. This suggested to us that the native clam might be particularly well-adapted to survive low oxygen conditions and grow rapidly, perhaps an untapped aquaculture option! So, we tasted some “big” clams (they seem to get not much larger than 3 cm) with one of our oyster-growing friends and can now pronounce them delicious. How about a new market for Benguela clams?
Well, even though Venerupis corrugatus seems to weather much of what nature dishes out to it, it’s not very resistant to science… or perhaps to the blunders of curious scientists. We collected around 3000 of them in late March from oyster gear coming out of Walvis Bay. They probably got a little bit of initial mistreatment that was not our fault: a freshwater rinse, and a 1-hour car ride in a small tub of water. Then, we distributed the clams into 3 sand or gravel-filled trays and watched them burrow in – at least most of them. We had to leave for Windhoek soon after that, so anchored the trays in a salt pond canal… that reached nearly 30C due to a series of bright, hot days. Half of the clams died. When we returned from Windhoek, we placed the trays back in the hatchery tanks, where another 50% died over several days. Then, we anchored the trays in a different, cooler part of the salt pond canal, just where the water is pumped in from the ocean. Over the next few days, the trays silted up and sank, with another half of the clams dying. However, by this time the surviving clams averaged 15 mm, and we had found live clams throughout the canal that had recruited and grown on their own. This gave us the perfect opportunity to set up our first experiment (as opposed to simply measuring conditions in different locations): we planted out the surviving clams into PVC rings embedded in the sediment, then put bird/fish exclosures around half and cage “controls” (just 2 sides) around the others. Because greater flamingos feed on invertebrates in the sediment, and a variety of waders (curlews, stilts, sandpipers, lapwings) probe for food, we think that these cages may allow us to document their ecological impact on infaunal communities. It’s so exciting to do a flamingo exclosure! And so nice not to have to accommodate 3-meter tides (as in any tideflat exclosure experiment in Willapa Bay) – in fact, the water barely goes up and down depending on how vigorously the pumps are working at the inlet.This experiment went up about 3 weeks ago as a “pilot” to see what would happen to structures – 2 exclosures were apparently trampled by birds, perhaps invisible to them on a dark night; and 1 exclosure (so far) has been gnawed by a hyena! Perfect evidence of the importance of replication.
We know that the tide has dropped, leaving dislodged mussels stranded on the beach, when we see the gulls flying up, dropping a large Perna, then following it to the ground to see if it has broken. The introduced clam in the salt pond, Ruditapes decussata (from the Channel Islands), was recently decimated by birds – hundreds of large shells lay broken around along the road. Alan has not been particularly impressed by gulls with such dysfunctional bills that they can’t even get into a dislodged bivalve, but Mr Klein says they’re actually quite smart: along areas of the coast with no hard substrate for dropping and cracking bivalves, they simply place Donax clams on the sand dunes until they gape from the heat and desiccation. While the gulls go for the large Perna mussels, turnstones seem to love the small Semimytilus. These have been washing up in clumps on the beach recently, probably dislodged by waves as the mussel beds have become thick, no longer attached to rock but to an accumulated layer of sand of several cm. It’s easy to see the pattern of patches within the mussel beds at low tide, and we suspect that, given the fast growth and small size of this mussel species, it would be possible to watch patch dynamics over months, rather than the years required by Paine and Levin on the Washington coast!
On the subject of mussels, I spent one illuminating afternoon looking for boring organisms in Perna. The idea came from our desire to begin testing top-down control of Polydora in the salt pond: what really caused the polychaete to essentially disappear in 2004? Was it isopods? Nemerteans? Since we have found so few Polydora in oyster shells – an infection rate of about 2% - we wondered if we could use spionids in mussel shells as a surrogate, then test to see if either isopods or nemerteans caused mortality. We know from walking along the beach that the wrack is full of bored mussels (you know, riddled with holes. You can’t be the other kind of bored when you’re dead!).
So, on a fair to middling low tide, JR walked down to the rocks by the Salt works, dressed in my normal Namibian field gear: bathing suit, wrap-around skirt, Crocs, wide-brimmed hat, long sleeves (it’s either that or a lot of sunscreen). The first thing I noticed was that the upper limit of Perna was just barely above the waves, which is not unusual given the rather small tidal amplitude, just a bit over 1 m. The second thing I noticed was that Perna at its upper limit is not bored, but instead seems to be sand-scoured except at its growing edge, sometimes to the point of having a concave outer shell surface. Finally, I found a few large mussels rolling around in a tidepool that had apparently been dislodged from lower down: they were covered with erect bryozoan epiphytes, red tufts of algae, and obviously bored. I put these in a bit of water in my bucket and carried them off hopefully to the ‘scopes at the hatchery, then spent the next 3 hours noticing a third thing: Most of the eroded burrows in Perna are full of phoronids!
For those of you not completely versed in marine biodiversity, I’ll simply state that Polydora is a polychaete annelid, a segmented worm, in a family characterized by the presence of two long palps on the head. I think I saw 2 long palps once in 15 shells, but was unable to extract any more – and in any case it may not even have been a boring spionid, but rather one that builds its tube in sediment. In contrast, phoronids are in an entirely separate invertebrate phylum. They are soft-bodied, unsegmented worms, with a horseshoe-shaped ring of tentacles on their head – this headdress made them quite unmistakable as soon as I found a shell that still contained live individuals. But then the next question: Did the phoronids make the tubes, or just occupy someone else’s burrow? Our satellite internet access at the beach came in handy once again, as I was able to search on “shell-boring phoronid” and learn that one of the 17 species of phoronids IN THE WORLD – and the smallest one, at that – makes burrows in mollusc shells. All the evidence points towards Namibian subtidal Perna perna full of Phoronis ovalis. It has been reported from a different Perna species in New Zealand, as well as from abalone in Chile. As far as we can tell from beach wrack, only one of the 4 mussel species on this coast hosts Phoronis ovalis, and we gather they are not a problem in aquaculture here. I guess that is good news for the oyster growers, but it puts another hold on our quest to discover the mystery of the missing Polydora.
Another quest we have set ourselves is a better understanding of Venerupis corrugatus, the native littleneck or steamer clam on this coast. We heard early on that this clam was ubiquitous, and indeed we’ve found it in mussel beds, intermixed with intertidal polychaetes, and washed up next to the Walvis Bay yacht club. Most impressively, we saw tiny (1-2 mm) individuals at incredible densities fouling the oyster culture gear in Walvis Bay, apparently a recent recruitment event at exactly the same time that so many oysters were dying in March! Two weeks later, the oyster gear coming out of Walvis Bay had clams around a cm long. This suggested to us that the native clam might be particularly well-adapted to survive low oxygen conditions and grow rapidly, perhaps an untapped aquaculture option! So, we tasted some “big” clams (they seem to get not much larger than 3 cm) with one of our oyster-growing friends and can now pronounce them delicious. How about a new market for Benguela clams?
Well, even though Venerupis corrugatus seems to weather much of what nature dishes out to it, it’s not very resistant to science… or perhaps to the blunders of curious scientists. We collected around 3000 of them in late March from oyster gear coming out of Walvis Bay. They probably got a little bit of initial mistreatment that was not our fault: a freshwater rinse, and a 1-hour car ride in a small tub of water. Then, we distributed the clams into 3 sand or gravel-filled trays and watched them burrow in – at least most of them. We had to leave for Windhoek soon after that, so anchored the trays in a salt pond canal… that reached nearly 30C due to a series of bright, hot days. Half of the clams died. When we returned from Windhoek, we placed the trays back in the hatchery tanks, where another 50% died over several days. Then, we anchored the trays in a different, cooler part of the salt pond canal, just where the water is pumped in from the ocean. Over the next few days, the trays silted up and sank, with another half of the clams dying. However, by this time the surviving clams averaged 15 mm, and we had found live clams throughout the canal that had recruited and grown on their own. This gave us the perfect opportunity to set up our first experiment (as opposed to simply measuring conditions in different locations): we planted out the surviving clams into PVC rings embedded in the sediment, then put bird/fish exclosures around half and cage “controls” (just 2 sides) around the others. Because greater flamingos feed on invertebrates in the sediment, and a variety of waders (curlews, stilts, sandpipers, lapwings) probe for food, we think that these cages may allow us to document their ecological impact on infaunal communities. It’s so exciting to do a flamingo exclosure! And so nice not to have to accommodate 3-meter tides (as in any tideflat exclosure experiment in Willapa Bay) – in fact, the water barely goes up and down depending on how vigorously the pumps are working at the inlet.This experiment went up about 3 weeks ago as a “pilot” to see what would happen to structures – 2 exclosures were apparently trampled by birds, perhaps invisible to them on a dark night; and 1 exclosure (so far) has been gnawed by a hyena! Perfect evidence of the importance of replication.
Panther Bake Marine Lab
In our 2nd letter to the Kleins/ Salt Company, we asked about the possibility of putting a trailer (here “caravan”) at our camping spot near the oyster hatchery. As the weather has grown cooler and damper, we have moved increasingly into the hatchery, especially for meals and, sigh, long stints on our computers. The hatchery is certainly warmer – a combination of wind protection and heated water – but also humid and a little cramped due to tanks, filters, raceways, and odds and ends of production and research equipment. Since April 6, the tanks have been full of Ostrea edulis larvae: one of the oysters that Alan collected from the salt pond must have been brooding, and he has since been father to 10s of thousands – feeding them microalgae from the guano pond, adjusting their temperature, and changing their water regularly. But the hatchery is not really a place to hang out during the winter. The Kleins were happy to allow some more permanent camping structures, so we started looking at a variety of options: The few used trailers that Alan priced were around $N70,000, out of our range. We were excited for a while about products offered by the Container Company, which provides shipping containers for all sorts of purposes, complete with doors and windows if you wish. But they too were a bit expensive. Meanwhile, the Kleins were also looking around for housing options, and they have been much more successful! First, they found a contractor to build a 5x4 m room on one side of the hatchery – as an extreme example of how cheap some materials and labor are, the entire concrete block building cost $N7000. About 7 people worked on it for nearly a week. Okay, so it’s not exactly square, and mortar was used generously to get the window and door to fit…. The Kleins have outfitted it with spare parts from their properties – a bay window with a bay view, work table and sink, and desk. It will be a fantastic place to use microscopes (less rusty than the hatchery sauna), work on papers, and watch the winter weather on the coast, while keeping an eye on any larvae that we can foster overwinter. So – there is now a new marine lab with running seawater on the Namibian coast, just meters away from some exceptional rocky intertidal areas, close to the salt ponds and bird sanctuary! We can easily see that there is a lifetime of questions to be answered here.
The Kleins also rescued a vintage 70s caravan from a neighbor’s backyard, painted the outside, cleaned the spiders out of the inside, and have provided us with a dining and living room. It’s about 2x3 m. The windows at each end prop open, and a bit of the top pops up, which allows Alan to look outside (and stand up straight!). The 2-burner stove seems heavenly after cooking on the Bluet (hunched over one burner), as does sitting at a table to eat. I guess after a month and a half and a little cold wind, camping has lost some of its luster. Katie has already fallen in love with the caravan (dubbed Hotel California by the Kleins), literally crying when it was hauled away to a safer storage place while we were in Windhoek. We owe the Kleins for many things – stimulating conversations, access to field sites, several fresh fish to grill on the braai (=barbecue in Namibia), the key to the hot shower near the Seabird Guano (Pty) building, and now these truly generous acts to help us be comfortable and productive. Well, the only drawback to the new lab is that it is possible to get locked inside the hatchery – this happened one night when I went back in to work on curriculum documents. I kept thinking that Alan would come rescue me as soon as Katie awoke and needed her mom to get back to sleep, which always happens by 10 pm… or at least by midnight… although sometimes she can sleep through until 2 am… and apparently Alan can pat her back to sleep until 3:30 am, when he at last opened the door and wondered when I was coming to bed. I was only too glad to do so.
So there it is: Panther Bake Marine Lab. Panther Bake should be pronounced in German, and Panther was the name of the German ship that placed a light (bake) at that site many decades ago. The light is now gone, but the name remains to grace the salt “mining” area and other activities on that stretch of coast.
The Kleins also rescued a vintage 70s caravan from a neighbor’s backyard, painted the outside, cleaned the spiders out of the inside, and have provided us with a dining and living room. It’s about 2x3 m. The windows at each end prop open, and a bit of the top pops up, which allows Alan to look outside (and stand up straight!). The 2-burner stove seems heavenly after cooking on the Bluet (hunched over one burner), as does sitting at a table to eat. I guess after a month and a half and a little cold wind, camping has lost some of its luster. Katie has already fallen in love with the caravan (dubbed Hotel California by the Kleins), literally crying when it was hauled away to a safer storage place while we were in Windhoek. We owe the Kleins for many things – stimulating conversations, access to field sites, several fresh fish to grill on the braai (=barbecue in Namibia), the key to the hot shower near the Seabird Guano (Pty) building, and now these truly generous acts to help us be comfortable and productive. Well, the only drawback to the new lab is that it is possible to get locked inside the hatchery – this happened one night when I went back in to work on curriculum documents. I kept thinking that Alan would come rescue me as soon as Katie awoke and needed her mom to get back to sleep, which always happens by 10 pm… or at least by midnight… although sometimes she can sleep through until 2 am… and apparently Alan can pat her back to sleep until 3:30 am, when he at last opened the door and wondered when I was coming to bed. I was only too glad to do so.
So there it is: Panther Bake Marine Lab. Panther Bake should be pronounced in German, and Panther was the name of the German ship that placed a light (bake) at that site many decades ago. The light is now gone, but the name remains to grace the salt “mining” area and other activities on that stretch of coast.
Namibian Business Innovation Center
AT is one of 2 advisors for NBIC, which the Finnish government may fund for Polytechnic to foster… business innovation! He participated in a 3-day brainstorming session Apr 2-4 (while K and J played with the local kids and spent an enjoyable morning at the craft center selecting handmade gifts to send to cousin Emma for her 6th birthday). And found it somewhat frustrating for the same reasons that have puzzled us about development of other programs here as well: The plans emphasize buildings and outcomes, not the people who actually have to carry out the plans. Our epiphany was this: we are essentially a business innovation center ourselves. Alan’s analysis of the high mortality of oysters in Walvis Bay has had the growers buzzing for weeks, considering ways to “harden” oysters. After all, wrote Alan, Crassostrea gigas is essentially an intertidal species, and hardening the spat is an essential step in its culture everywhere in the world. In Japan where it is native, scallop shells are hung in Sendai Bay for recruitment, then moved to intertidal racks in a small cove over winter, then moved back to Sendai Bay where the oysters grow in clusters to harvest size. In Washington, oyster shells are packed in mesh bags to receive recruits, and these bags are stacked in piles in the intertidal zone over winter, before being broken apart and scattered for the oysters to grow on bottom. In contrast, hardening has not been part of oyster culture in Walvis Bay. There, oysters remain submerged from the time of settlement, removed for perhaps a day every 6 weeks for cleaning, which chips the thin, subtidal, fast-growing shell. These chipped individuals certainly cannot close up against toxic conditions, and even the intact ones have poor abilities to close. Hardening could help these oysters through some periods like those experienced in March. The oyster growers here are getting other help and advice as well, about triploids, clams, phytoplankton, … and all out of the back of our Kombi! The point is, you don’t get a business innovation center (or a marine lab, or a degree program) through a building and a plan on paper. You get it with qualified people.
It’s funny to me that I regularly give Alan a hard time about not writing up his scientific papers, which on average 7 people ever read (a scientific fact!). But, many more than 7 people have read his oyster mortality report, and they’re actually experimenting with some new practices as a result!
It’s funny to me that I regularly give Alan a hard time about not writing up his scientific papers, which on average 7 people ever read (a scientific fact!). But, many more than 7 people have read his oyster mortality report, and they’re actually experimenting with some new practices as a result!
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