Issue 31’s cover was a little unusual for us. For one thing, it actually involves a fish (ehrmagherd!), but the way that the giant trevally is shot, the angle, the viscosity of the water and the background, it looks like a futuristic car unveiled at an auto show.

It was taken on the fly by fisheries scientist Dr JD Filmalter while he, Dr Ryan Daly and Dr Tessa Hempson were tagging fish at the massive annual spawning aggregation they have been monitoring for the last six years. More on that here. In this short Q&A, JD explains how he got the shot, the thinking behind a “GT jacuzzi” and more about the process of tagging big GTs like our cover model.

Tell us how the shot came about?
That specific shot I got using my iPhone and my creative wizardry (ed, note: this was said with heavy sarcasm). I’ve seen lots of GT shots over the years and there was one particular giant trevally shot that I always loved. I think it came from Cosmo or the Alphonse crew and it’s a head-on view with the guy picking it up and the GT’s eyes just above the water line. I’ve always wanted to re-create it but have never got it right. So with this I just asked Ryan to hold the GT up and I stuck my phone in there, not really hoping to get that exact shot but hoping to get something good.

How many GTs did you tag that day?
Without going back and digging in the records I think we tagged two or three GTs that day.

That week?
It was a tough week and I think we tagged 14 GTs. We had two good days – 4 and 6, but the rest of the time was hard-going.

Is there a change in the colour of these fish in the water vs colour when they are in the boat?
Sometimes they do change colour, but most of the time they stay the same – bright silver and grey beautifulness. That could be because normally after the surgery there’s a bit more stress being in the jacuzzi for a while.

Can you give us some detail on the jacuzzi itself. Who makes them? Do you use the same contraption for other species?
That jacuzzi was made up by someone in Durban for Ryan, but I have them made up in CT too by a tent manufacturing place in Somerset West that makes them for me, but any canvas-working place can do them like Christies’ Sport. We use exactly the same contraption for many different species. It’s also known as a ‘Kob-cuzzi’ and a ‘Grunter swem-bad’. We use them flat-out for everything, as they are very useful, very versatile.

The design is based on Paul Cowley’s design for beach tagging of big fish. You dig a hole and put this canvas trough inside and fill it with water so the fish is happy. We’ve just kind of adapted and moved it to the boat and put poles in it so it rests across the boat allowing us to work on the fish. Most of the time we use bamboo/Indian cane poles from the tuna fishery in Cape Town because they are strong enough to hold the weight of the water and the fish when the jacuzzi is slung across the vessel. Jacuzzis come in many colours – I’ve got a blue one, a white one, that one’s a grey one, and once upon a time I had a camo green one. White is really nice on the beach where the water gets really warm. Some have insulated covers.

Dr JD Filmalter getting cozy with a kob in a jacuzzi

Dr JD Filmalter getting cozy with a kob in a jacuzzi

Have they caught on with serious anglers who are not scientists?
Lots of people contact me about getting them for big kob. A few years a go on the Breede a really nice gent sponsored a whole bunch of them for people catching big kob. Since then we have had a whole bunch made through the Live Oceans Trust so we do donate them to people that we feel will benefit from them. Obviously we only give them to guys that catch big fish regularly (ed:so not you, dear reader) because it’s quite a ball-ache to carry that thing around if you are not on a boat. There are smaller versions as well for tagging leervis on the rocks. I recently got contacted by Nathan Pfahl from Mavungana Flyfishing who wants one for tigers at Pongola. It’s a great working piece of machinery that we are always changing and updating.

What’s the procedure when bringing a giant trevally into the boat for tagging? Is it a multi-person job?
Lifting a GT is generally a multi-person job depending on the size of the fish. One person does a double-wrap on the leader and the other person grabs the tail and we lift it sideways, flat, over the gunnel and straight into the jacuzzi which has already been filled with water by one of the people on the boat. Normally there’s a minimum of three of us on the boat. We keep topping the water up in the jacuzzi while the fish is in there. Normally they are in there for 5-10 minutes while we prod and poke and take our scientific samples.

giant trevally


For more on these giant trevally and the work JD and his colleagues do, get stuck in to issue 31 of The Mission below. As always, it’s free.