Helen Cadwallader is a marine biologist and conservationist currently working and living in New Zealand and specialising in sharks and rays. She shares her story with us and her top tips for living more sustainably.
Can you tell us what lead you to get started in marine biology?
I’ve always loved everything about the natural world, and grew up poking around in rock pools and snorkelling on family holidays. I did an undergrad degree in Biology, which was pretty broad and then when working out what I wanted to do with my life I did some volunteering here in New Zealand, assisting a PhD student with her research on Dolphins and the effect that swim with dolphins tourism was having on their behaviour. I went on to do more volunteering with some Humpback Whale research and then made my way back to Wales to do a masters in marine biology where I studied cleaner fish and their interactions with thresher sharks in the Philippines. I knew that I wanted to specialise in sharks or rays and when the opportunity came up to study Rays in New Zealand for a PhD I jumped on it and haven’t looked back!
Can you tell us what’s the single most impactful thing you’ve seen in the ocean?
I did two seasons of work in the marine tourism sector here in NZ and saw some amazing sights, and some not so great ones. Things that I only ever expected to see on documentaries, like Blue marlin and dolphins surrounding a bait-ball of fish but also the purse-seine-net fishing boats - these boats surround those same shoals of fish with their net and bring them on board. If there are other species in amongst, they get caught too! I’d learned about them, but seeing it in person was pretty shocking! If you eat fish, make sure it’s sustainable and you know how it’s caught!
What do you find the biggest obstacle to be in the conservation work that you do?
I think the biggest obstacle to any conservation work is money, both the money it costs to train and volunteer (the more experience you have the better) but also the money that research costs. Scientists are forever writing grant applications and fighting for money, rather than spending all of their time doing the research. Theres limited funds available, and you spend a lot of time justifying why what you do is the most important. When in reality, it’s ALL important, no species is stand-alone, they’re all part of an ecosystem, and if one tiny portion of that ecosystem is lost, then the system doesn’t work properly anymore!
Can you tell us about the accumulation of heavy metals in marine wildlife?
It’s an accumulatory process, so when it rains, metal run off from vehicles or agriculture or industrial areas, things like lead, cadmium, mercury, chromium, can be washed into the water systems. These metals can then be present in small amounts in the water, and in the sediment for a long time. Filter feeding organisms, like shellfish, can take up these metals and are then eaten by fish. Each fish might eat lots of shellfish and will accumulate the metal from all of them into their bodies, increasing the concentration. That fish might be eaten by a bigger fish and the same thing happens again, eventually it will reach the top of the food-chain, and apex predatory animals like Tuna, large sharks and Orca may end up accumulating really high levels of these chemicals. Sharks and rays don’t have a swim bladder like other fish, they have a really big fatty liver that provides their floatation and its because of this that are thought to take up and hold on to metals at a faster rate. If you then think about the Orca, they eat the livers of sharks and rays (even white sharks in some areas!) as they’re really nutritious, but along with this they’re getting all of this accumulated heavy metals and other contaminants like pesticides etc.
How have you found the transition from Wales to New Zealand and what’s your favourite thing about living and working in such a beautiful and diverse country?
It’s been interesting and has definitely had it’s ups and downs! I have cousins over here, which helps with the homesickness, and being in such a beautiful country right by the beach really helps! I come from rural mid-wales, so it’s a bit like a parallel universe landscape-wise, the hot summers and warm water definitely helps too! Some things that you don’t think about until you move away is how long it takes to order anything online, a least 2 weeks for most deliveries from the UK! Also NZ is really big, you feel a bit guilty flying for meetings in other cities, but it’s a difference between 40 minutes flying between Auckland and Wellington or 10 hours driving! That plus if you want to go ANYWHERE else, you have to fly, so the carbon footprint isn’t ideal, but I hope I’m making up for it in other ways!
On an every day level, can you give our readers a few easy take home points that they can implement in their daily lives that go some way to helping conserve marine wildlife?
I think recently, loads has been promoted in the media with the plastic straws thing and the cotton buds etc, and all that is great! Cutting down single use plastic use is something we all can do, that will have an effect on the future of the oceans. I stick to the "take three” rule, so whenever I go for a walk to the beach, or the park or the forest, to make sure I take at least three pieces of rubbish away and put them in a bin, or recycle if possible. Another pretty big thing is that I don’t eat tuna. Even though there are ‘dolphin friendly’ tuna varieties now, (that just means they’re not caught by seine netting) the majority of tuna is caught on longline fishing boats. Longliners kill tens of millions of sharks that were caught as by catch every year, we can’t have a sustainable ocean if this many apex predators are lost, the ecosystems are going to collapse. It’s back to that if you’re going to eat fish, make sure its sustainably caught. The Marine stewardship council in the UK do a list of sustainable and non-sustainable fisheries each year, I think theres even an app now! They put blue ticks on sustainable fish in supermarkets!
We started Stay Wild Swim because of our passion for the ocean. How would you describe your relationship with the ocean?
The ocean is in my blood, even though I grew up 60 miles from the sea, both my grandfathers spent a lot of time on the ocean, If I need headspace or clarity I go to the ocean. We can learn so much from it, it is the most beautiful thing on this planet, yet has the power to destroy us. We should be doing everything we can to improve, and save the creatures and ecosystems that it protects.