Most big GT on some spots and not in others, WHY ?

[Sacco Gerard]

I still have many difficulties to speak in English    but I would like your opinion on the topic.

Why  a large majority of big GT are fished in places like south  Oman is possible, during my trip there the smallest weigh about 30k, 52k  for  the biggest on scale and the largest estimated at 65 (155x120) while in other places like Andaman, a GT trophy  is quite rare, I made 2 trips there,  about 370 GT in the boat at 2 and 3 fishermen and the largest does not exceed 36k.

Is this an environmental problem, ? of plenty of food, ? this question intrigues me.
If you have an idea on the subject, let me know and thank you to enlighten me of the small fisherman that I am 

[Ed Nicholas]

Hi Sacco,

It is a question that i have often pondered myself and pretty much what has driven us to launching the first GT tagging programme in the region/one of only a handful in the Word to see if we can get some info on these fish.

What i can say is that it is not only the GT that grow huge here but almost every species we come across are contenders for records, especially the various species of Trevally.

As all who have fished S.Oman will have seen there is just a constant supply of bait here. With live wells on the boat we often drop sabiki and pull up the 6 hooks with up to 4 species of bait on them at any period of the season. Add the huge amount of fusiliers at the islands and the predators can feast all day every day.

The summer monsoon is also what makes the Islands so unique with nutrient rich currents battering the islands for 3-4 months of the year. This phenomenon is responsible for the only nonmigratory Humpback Whales in the oceans and also one of the only places where Kelp grows along side Coral reef.

I personally still believe the GTs migrate between S.Oman and Socotra as there is a definite window during the season where they are very scarce. I also note that the GTs pictured in Socotra are of a very similar shape (FAT!) to the Omani ones. That is just my 2 cents though and i may very well be wrong with the fish moving to deep water instead of the very shallow reefs they love here.

One thing is for sure though if you want the biggest angriest GT on the planet you cant really look past S.Oman.

[Mark Harris]

I think Ed hits the nail on the head there by identifying that in Southern Oman it is not just GTs. The Golden Trevally, Yellow-spotted Trevally, Talang Queenfish etc are all ridiculously large.  And not just the odd trophy fish which you might find elsewhere - lots of very large examples.  Over-sized is the norm not the exception.

That must mean it is something to do with the environment in which they live, and the never-ending supply of easy food seems the most obvious answer.

Nice snippet about kelp growing alongside coral reef by the way - did not know that.

[Andy Rowe]

Have to agree on the diet point put forward by Ed, the food chain in that part of the Indian ocean is extremely healthy and must be feed by very  nutrient rich currents from the south. Better diets mean bigger specimens Sth Omani GT's must be kind of analogous to the Kodiac Island brown bears which have a salmon rich diet and are far bigger than the other members of their species which occur in different geographic regions.

[Luke Wyrsta]

In my opinion it's the combination of significant tidal / current influence, deep water access close-by (shelf) [upwellings] and being situated in a convergent current zone. Not only do these places provide an environment rich and diverse in bait offerings but they also attract the strongest and most elite specimens of GT! Find all these and most of the time you will have ticked all the boxes for an area that GT will spawn in.

I think evidence to also support this is for some trophy destinations to be located in "temperate" regions of their given location I.e. New Caledonia is partially sub-tropical receiving both cool and hot convergence of current and weather, as does Fraser Island and parts of SE QLD. This is also reflected to a degree in Tokara, Japan.

There will always be anomalies creating freaks of nature places like Socotra, Southern Oman, Midway etc... Again, put those locations on paper and you'll find most if not all the features aforementioned will be present.

Southern Oman is a magical place but let's not forget trophy locations like New Caledonia and Tokara which also hold world records, including the current AT record. New Caledonia still remains the location where I have seen GT that would make a 65kg specimen look like a guppy! 

[Sacco Gerard]

Thanks for your answers   
I do believe that the wealth of the food that is found south of Oman is an explanation for the presence of large fish.
I only went at Ash Shuwaymiyah only once in 2011, so I do not have much experience of the spot but I'm still surprised not to have seen a small Gt from 10 to 15k. when I was fishing near of HALLANIYAT ISLANDS
When we  fish with lures fast handling as sliders, Orion flapper and Big nose for example, in principle small GT are faster to tackle this kind of lures, I checked around many spots,  in Oman it was not the case during my trip, it is still surprising

[Nick Bowles]

This is a good question and something that we have discussed for many years around many a fire. There are a lot of theories but what I believe is that most of the big fish that we see in Oman and Yemen are pelagic. After being lucky enough to fish a lot of GT places like Maldives, Seychelles, Mozambique, Tanzania, Tokara, Musandam, Hallaniyat and Socotra you can definitely see a lot of differences in the fish in the various areas and also at various times of the year. What I think happens is most of the smaller GTs start off in nursery areas like Maldives, Seychelles, Lakshadweep Islands where there are shallow atolls and quite areas for the GTs to grow and to stay away from predators and also where there is easy prey for them to feed on but most of what they feed on are smaller prey and not in big numbers. When they start getting towards a decent size they start to migrate into deeper water joining up into larger shoals and start to swim on currents and deeper water in search of bigger and more food hence heading for areas with an abundance of food. The smaller fish will not survive to well so the GTs have to get to a certain size on average ie 25kgs or something in this range.

The shoals then travel to areas to feed and spawn like Oman for turtle hatching, Southern Oman/Socotra spawning etc. I have seen over 1200 GT netted in a day in Oman when the turtles are hatching and watched the local fisherman weigh the fish for over an hour and there was not one GT under 30kgs, there is no way these fish are local as most of the year there are no GTs in this area, they have come to the area for a specific reason and the lack of small fish must only mean that they are growing up somewhere else. Then when we have fished Seychelles and Maldives we have caught a lot of GTs with very few over 25kg mark. All the fish are smaller and not as aggressive. So conclusion is if the smaller fish are in the Atolls/shallow reef areas and the bigger fish are in the deeper waters leading onto islands like Socotra, Hallaniyat, Tokara etc then they have to come there from somewhere and not resident. They may be resident for a while but not permanent. If there are not to many small fish must mean they are growing up somewhere else.

I think the theory is that you will find a lot of big GTs in areas that has very deep water around islands like Hallaniyat, Socotra, New Caledonia, Tokara, Komodo, Hawaii. Then you will generally find smaller GTs in areas with atolls and shallow water like Maldives, Seychelles, some areas of the Coral sea, etc. The big GTs have to eat a lot to keep them going and to chase a mullet around the flats is not going to do much and they need big shoals of baitfish, squid, turtles etc and then they also want to breed and find a place with a lot of other big mature breeding fish and hence the spawning in places like Hallaniyat and Tokara which you can hit right and catch a lot of big fish in a small area.

This all said I have caught GTs off the shore in Oman around the 2kg mark and we have caught 40kg+ GTs in Maldives, so there is definately some cross over and the theory is not perfect but I think in general it could be a possibility. But with anything this is my theory and every day we work on new ideas and theories to try and better understand our chosen species to target. Hallaniyat and Socotra are definately an anomally and something that is very special and something I hope we can all enjoy for a long time to come!

Cheers,
Nick

[Ed Nicholas]

Excellent to see a variety of thoughts and input. I meant no disrespect at all to New Cal and all the other established /proven monster GT locations but was simply saying S.Oman is right up there and a very unique place to fish 

[Mark Harris]

Some really, really smart stuff in this thread and how good is it to have anglers really thinking about the fish and not just about catching them, and the the tackle that should be used? Tremendous.

Nick, a really smart line of thinking there if I may so.  Both casual observations, and hopefully more and more results from tagging, can only help us all understand more about this magnificent fish.