Dolphinfish!

By Brett Vercoe

Dolphinfish are well known for their dogged fighting abilities and are considered an important gamefish highly sought by fishers all around the world. In Hawaii they are known as ‘Mahi-mahi’ which means ‘strong-strong’ in reference to its great strength as a swimmer. In Latin America they are referred to as ‘Dorado’ which is Spanish for gold and refers to its beautiful gold sided appearance.

Dolphinfish are famous for their leaps and tail walks on line and will occasionally break the surface after being speared. They are abundant and capable of sustaining heavy fishing pressure due to their high reproductive rate, widespread habitat and minimal commercial fishing pressure worldwide.

With increasing interest in bluewater hunting over recent years more and more spearfishers are venturing out to the deeper offshore habitats for species like Dolphinfish and discovering new thrills, adventures and opportunities. Because Dolphinfish are normally found in clear offshore waters you may find them a great alternative when inshore conditions are poor due to swell or limited visibility. I have put together a few items of interest that may make it easier for you to plan your first or next trip out to sea in pursuit of this great bluewater gamefish.

BIOLOGY

Dolphinfish (Coryphaena hippurus) are a handsome pelagic predator equipped with a huge dorsal fin that runs from their head all the way back to their deeply forked tail. They have a large mouth, many fine teeth and may reach a size of up to 45 kg’s. Dolphinfish are more surface oriented than any other big game fish. They school in large numbers and are capable of speeds as high as 80km/h. Dolphinfish inhabit oceanic waters near the edges of the continental shelves in tropical and sub-tropical environments worldwide. In Australia they are rarely found inshore of the 55 metre depth contour. Younger fish are normally associated with near-shore fishing locations while the larger animals are generally found further offshore. Their colours are truly beautiful with a spectacular mix of blues and greens on a black speckled gold background. Dolphinfish make a great photographic trophy, but capture your images quickly as their colours fade rapidly after death and they mark easily if handled roughly.

Male Dolphinfish are called bulls and have a distinctive bony crest on the head that is not present in females. They are commonly found near floating objects that may harbour prey species. These objects can be as substantial as FADs (Fish Attracting Devices) and floating logs or as insignificant as trap floats, wave rider buoys or even small streams of sea foam. Dolphinfish are voracious predators devouring a variety of ocean species including squid, shrimp, crustaceans and a variety of finfish, including juveniles of their own kind.

The insatiable appetite of Dolphinfish may be connected to their high metabolism and tremendous growth rate of over 50 cm a year and gaining an average of 10% of their body weight per day!!. They typically live a maximum of five years and reach sexual maturity at just 6 months. These traits coupled with the fact that Dolphinfish are not targeted commercially in many locations throughout the world help to make them a viable and resilient species capable of sustaining their population. Although they are almost at the top of the food web, Dolphinfish fall prey to a number of other oceanic predators including sharks, wahoo, tuna and marlin species.

SEASONS

Dolphinfish are migratory and each year they move away from the equator in Spring and Summer and toward the equator during Autumn and Winter as they seek water temperatures of above 20 degrees Celsius. Spawning occurs in Spring or early Summer each year with the female laying around 200,000 eggs in the open ocean.

EQUIPMENT

First and foremost you need a really seaworthy vessel capable of operating in offshore conditions and equipped with a radio capable of reaching shore, an EPIRB (Emergency Position Indicating Radio Beacon) and a good compass. A GPS is essential both for finding your way back in poor visibility and logging the locations of any wave rider buoys, FADs or fish trap floats that you may encounter.

Big bull Dolphinfish tend to hang back in the school and require a flat shooting, long range gun. The possibility of encountering a marlin, tuna or wahoo is ever present and with this in mind I always prefer to be ‘over-gunned’ when chasing Dolphinfish. My personal preference is a twin rubbered 1.4 metre Rob Allen Railgun with a 1.7metre 7mm shaft. The gun is clipped off to about 15metres of 200kg mono (eliminating the risk of spooking fish with a visible rig line) which in turn connects to 20 metres of good bungee terminating at an 11 litre foam filled Rob Allen float. This rig has proven itself on sailfish, marlin, wahoo and tuna and handles big Dolphinfish with ease. I will sometimes connect a short second bungee and an air filled Rob Allen 11 litre float if I am working an area with good potential for larger bluewater species.

Larger Dolphinfish fight hard and often require an Iki spike or stabbing knife to stop them thrashing. They also have a habit of wrapping you up in the rig line so of course the mandatory sharp knife should be worn at all times.

TECHNIQUE

Some spearos experienced in targeting Dolphinfish believe they will spook them if you swim up current toward them. Frequent drifts do seem to work better than staying in the vicinity of the floating object (FAD, log, trap float, wave rider buoy etc). This goes for both divers and boats.

Even though you will often encounter schools within centimetres of the sea surface it is best to duckdive down a metre or so to escape the difficult shooting conditions caused by chop and surface wave action. You’ll be amazed at how much steadier your aim will be once you leave the surface. Rarely will you need to dive beyond 5 to 10 metres while hunting Dolphinfish, with the vast majority of them being taken at about 3 to 5 metres. Pick out an individual within the school and lock onto it so that you’re not distracted by the swirling mass of fish in front of you. Keep in mind that the often clear oceanic waters can make fish size and range estimation tricky until you’re used to it. Is that a 10kg fish at ten metres or a 5kg fish at 5 metres?

If you have a powerful, accurate and flat shooting gun and you’re proficient with it don’t hesitate in taking a longer shot at that big bull hanging way back in the school. The shape of these fish, particularly the bulls, makes them an excellent target. Dolphinfish are quite large when seen broadside however they are thin and light skinned and it’s not uncommon to toggle a second fish from a school with a single shot. If you or your dive buddy shoot a Dolphinfish the school will mob the injured fish for 30 seconds or so making a second shot possible. Dolphinfish should be chilled immediately after capture to best preserve their texture and great eating qualities.

INCIDENTAL CAPTURES

Wahoo, assorted tuna and black, striped and blue marlin have been seen by spearfishers targeting Dolphinfish. Just last season Gavin Smithers and I witnessed a Stripey of about 200 kg hunting Dolphinfish and sending a school erupting into the air just as we arrived at a set of trap floats. Kingfish are also occasionally encountered but they are usually juveniles.

SAFETY PRECAUTIONS

In the majority of locations where Dolphinfish are found you will be a long way from land and assistance. For this reason it is very important that you check weather conditions prior to departure and monitor them closely throughout the day. Be aware that coastal breezes may not impact once you exceed 10 or so kilometres offshore and it’s not unusual after having had a calm day out on the shelf to return to a raging inshore coastal breeze.

Always have a capable boat handler to watch over the spearos at all times and work out a series of hand signals so that the operator understands if he is needed urgently. Usually the water will be too deep to anchor anyway so someone must stay with the boat. The boat handler should keep an eye out for sudden current changes or a spearo suddenly being towed away after hitting a larger bluewater species. At least one person aboard should have some basic first aid training (preferably not the person who gets injured!!) and an adequate kit kept aboard the boat. In many locations you could be some hours from additional help.

Choppy seas and strong currents require spearos to use a large highly visible float and flag so that the boat handler can keep track of them at all times. It’s also a good idea to carry a whistle and after a savage lesson in the Coral Sea I now also attach a red hand held flare to my Rob Allen float when working in high current areas (vacuum sealed and attached with 2 o’rings). A new range of personal EPIRBS have recently come onto the market. They are very compact and waterproof to about 70 metres providing added insurance for anyone lost at sea.

LEGALITIES

Legislation of course varies from State to State and Country to Country so check with the relevant Authorities before setting out after Dolphinfish. Remember that Fisheries legislation is regularly updated so check the relevant Agency website to keep up to speed with the latest rules.

NSW, Australia - Be aware that it is an offence to tie off to fish traps in NSW waters so your boat handler will need to drop you upcurrent and recover all divers once they’ve drifted away from the fish. There are no size limits on Dolphinfish in NSW however a maximum bag limit of 20 fish per person applies. As a result of the NSW Recreational Fishing License a number of Fish Attracting Devices are being deployed off the NSW coast .

RECORDS

The current Australian spearfishing record is a bull Dolphinfish of 21kg taken by Alex Lewis off the Queensland coast in December, 2002. The current IUSA world spearfishing record is a bull of 34.6kgs taken by Peter McGonagle in Mexico. A bull Dolphinfish exceeding 40kg was landed by a game fisher off Coffs Harbour, NSW, in 2002 which proves that there is still potential for the current records to be improved upon.

CONCLUSION

If you are lucky enough to live in a location where your water temps exceed 20 degrees Celsius then you really should make an attempt to target Dolphinfish. They are exciting to chase, great sport, great eating, provide another option when inshore conditions are unfavourable and add a little variety to your spearfishing adventures. As long as you use appropriate equipment and consider the safety issues involved I’m sure you’ll be hooked on Dolphinfish!!

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