Updated: Oct 13, 2021
So the Dolphinfish, or Mahi Mahi I think is the more commonly used name. Mainly you would think to avoid the use of the word Dolphin when you a referring to something you catch or even serve at a restaurant. Not necessarily my favorite fish to catch. But taking everything into account, including their colours, how they act, school up and of course their sustainability. I could easily call it in general ,my favourite fish. Those in the know about me and Coral Bay may have a laugh and think that’s a bit ironic. But I’ll leave it at that unless you're handy on google you might work it out. This is not going to be about where to find them, or how to catch them. Plenty of people have done that before, and I won’t pretend to act like I know the best way to go about it. But most of all I wouldn’t enjoy writing about that anyway. To me, the most enjoyable part of fishing is working that stuff out for yourself. Like normal this will be more about my personal experiences and some interesting facts that you can then hopefully pull out your ass at the right time.
So the name, well it's got plenty. I like to stick with Dolly, but as I said, Mahi Mahi is probably the most common. Coming from Hawaii meaning “strong strong” or “very strong”. Then there’s Dorado from Mexico, it’s Spanish for “golden”. With just about every language having their own name for the Dolly. lampuka (Mediterranean) goldmakrele (German), koryfena (Polish), shiira (Japanese). The list goes on, but one that is sometimes used Pompano. But this is actually a different fish. You have the Common Dolphinfish (Coryphaena hippurus). And then its smaller cousin the Pompano Dolphinfish (Coryphaena equiselis). The Pompano is less common (makes sense). It is smaller, only growing to a maximum of 127cm and the bulls lack the large square head. Its colours are not as varied with the sides of the fish normally staying silver/yellow. But the sure way to tell them apart is the dorsal fin of the Pompano Dolphinfish extends all the way to the base of the tail, where on the Common Dolphinfish they the dorsal stops just short of the tail.
So for a long time, Dolphinfish were commonly just known as Dolphin. It’s only in relatively recent years it has moved to Dolphinfish or even to its foreign names as Mahi Mahi and Dorado. The reason for this like I mentioned was to make sure people didn’t think that you were referring to Flipper when you caught them, or more importantly when it's on the menu at a restaurant. There seems to be a lot of uncertainty and plenty of theories of why the word Dolphin was originally used to describe them alongside the very unrelated mammal Flipper. In Flippers case, the word Dolphin goes back to the Greek word delphys (delphus) meaning ‘womb’. There are theories about this too but the most obvious one is the fact that being a mammal the dolphins give birth to developed young and in turn would have a womb, unlike most other ocean creatures. But as for how this was related to the Dolphinfish is a bit more of a mystery.
So the first recorded use of the word dolphin being used to describe them was in 1627 by captain John Smith. Where he reports in his logs using hooks to catch dolphins or dorado. Well, that name sounds made up “John Smith”. But that's from the Oxford English dictionary so will take their word for it. Most people seem to think it was because of one of many similarities they shared with the Flipper. Like the rounded forehead that would be similar to Flipper missing their rostrum or beak, a bit of a long shot. Or some say it was because they can sometimes follow a moving boat as Flipper does. I have even read that large schools can even be heard making similar noises to flipper underwater to communicate. That’s news to me but will keep an ear out next time. I thought I had it sussed when I found a past scientific name “Coryphaena dolfyn”. Now I really don’t have much idea about how the naming of species or Taxonomy works, but the current name of “Coryphaena hippurus” came about in 1758 by Linnaeus. But the now rejected name “Coryphaena dolfyn” appeared in 1833 by Valenciennes. I’m not sure if this was because they were the same species or the rule of classification got changed. But the fact that the name only appeared in 1833, I think this may have just been used became they were already commonly known as dolphins, not the other way around. But as always more than happy to be corrected if someone knows for sure.
So let’s get onto the fish itself. So many amazing things about these fish. Starting with the most obvious one to people that may have only seen these things in photos. The colours on this fish has no rival. Well, maybe a fully lit-up Blue or Striped Marlin, but that's about it. Not only do these things look amazing in photos, to see them all lit up in the water is next level. From bright greens, yellows, blues, and a mix of everything in between. They can flash between colours using chromatophores, skin colour changing cells, or something like that. I might look deeper into that another time. They do seem to have different colours when they fired up, but I read that some Florida Keys crews reckon they have it down pact. Blue when calm, green when fired up, yellow in distress, but I’m not too sure about that, just seems like a random mix to me. Unfortunately, they do all go a dull green or even grey once they have been killed. But a good ice slurry will help them keep any colours that they have left. But if you want photos with these things, straight away is the go.
So the colours are cool, but the growth rate and reproduction are what make these things next level. These things rarely live over 4 years, but most will barely make it to 2 years. They pack a lot into their short fast-paced lives. The fish can spawn as young as 5-6months, with cows being around 50cm and 2.5kg by this age. Bulls are mature at the same age but are usually a bit larger. Cows can release anything from 50,000 to 1,500,000 eggs each spawning cycle. I found very mixed reports on how often they spawn, some studies saying as often as every 6 weeks, but most say to 2-3 times a year. The overall growth rate is dependent upon food availability, but by the end of the first year, they are normally easily well over 100cm (fork length) and can reach much as 10kg in good conditions. They do this by consuming 6-20% of their body weight each day. So not really that efficient, as they burn most of that just finding more food. But still an amazing growth rate. So on paper, these fish could be an excellent sustainable food source and they are to a point. But because they are a very migratory species true management would require an international approach. They have been tracked and average around 20nm per day in a lot of cases, so always on the move. They are all the perfect candidates for aquaculture, but my understanding is that it's still a work in progress, and are a difficult species to breed in captivity But I’m keen to look into this further down the track. But we do know they make a perfect gamefish. Common bycatch while chasing billfish, you should feel no regret chucking a couple in the esky. The all-tackle world record for a dolly is 87lb or 39.5kg, caught in Costa Rica in 1975. The Australian record is a respectable 31.0kg Port Stevens NSW 1981. But closer to home the best we have managed in WA is 19.3kg model in 1997 out of Exmouth.
The outright best thing about Dollys is their schooling and aggregation behavior. If you in a favorable area for them. That being temperate, subtropical, and tropical offshore waters. So pretty much everywhere that's not freezing. Just about anything floating on or just below the surface, is likely to have a few hanging off it. Whether that be just some weed on a current line, discarded fishing gear, or even a small log or branch in the water. Obviously, they are also normally the first species to arrive on any FAD. In the right conditions, it’s a daily occurrence to get a school come past and have a look at the boat while on anchor fishing offshore. The fish always seem to be in numbers relative to their size. You get large numbers or smaller ones but the larger they get there are generally fewer in the school. It’s quite common to find particularly large fish swimming around in just pairs. Because of this lots of crews have come up with the theory that they have mates for life. But there is no proof of this. What reinforces this theory is If you catch one of the two, the other will follow it right to the boat, and even hang around where they last saw their mate for some time. But the same is also true about a whole school. You hook one and the rest will follow it right up to the boat. This seems more prevalent in the smaller schools of larger fish. So if you had a school of just 2 fish they would definitely appear as mates.
One thing I have noticed, at least for with then in the area we fish anyway. They are either hungry or not. I’m almost to the point that if we have a school come around the boat, I will just chuck a handful of bait in the water. It gets eaten, good we are on. If not I almost don’t even bother. It is true sometimes they take a bit to get excited, and if you get one to bite, keep it in the water and the rest will follow the excitement. But a lot of the time they come past the boat for a look but are just not interested no matter what you try. If they do take the bait, while we are on anchor bottom fishing we do have our special way of going about getting them on board. It involves 3-4 meters of 200lb mono, a strong circle hook, and 2 or 3 double wraps. Yep, we have up to 12 other lines in the water while fishing, so as much fun as it would be we can not afford to have a dolly going for a run wrapping the whole boat up. We chuck the length of mono in, let them take it, and just rip them straight out of the water before they get any traction. Then it’s just the case of jumping on top of the thing on deck before it works out what’s going on while trying not to let it smack you in the nuts.
That’s the thing with dolly’s every catch seems to be an event, you rarely catch the one, and they always put on a show. Jumping and carrying on every time. I mean these things can sprint up to 50kt. Even while trolling, as I mentioned, it seems they are hungry or not interested. One day you will be trying to get one trolling right past a FAD that's packed with them and as you approach they either dive or just don’t react at all. Other times you just catch a glance of green or yellow out the corner of your eye and the next thing you know every rod is going off. The Dolly below was part of a 5-way hookup, yep all 5 rods onto Dollys during a Marlin comp in Exmouth. The biggest Dollys I have ever seen and all similar in size. That's what happens when you stray too close to a FAD when they are hungry. But of course, I’m standing on the bridge watching the boys have a ball with the chassis on deck, and there's a nice Black Marin 30m off the back of the boat trying to work out what’s going. Meanwhile, all our reels have fish on them. And of course, we came second in the Marlin category only to line class with equal fish in that comp. But my favorite way of catching them is just to yank them straight out of the water, no hooks required (well one big one). As I said when you catch one out of the school it’s quite common to have one or more other fish follow them all the way to the boat. Quite some time ago I was about to gaff a fish that had been hooked by a punter on a deck winch. When I noticed that there was a fish right next to that one well and truly in reach. So nabbed that one first, then went back and got the fish that was hooked on the line. I have tried to repeat this a few times without luck but my decky was recently able to pull it off while I held one in the water at the back of the boat. So now of course you're not a real decky on my boat until you have free gaffed a Dolly.