Keeping Marine Hammerhead Shark in captivity

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aquatopusa

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I am a 12 year experienced and license commercial shark collector for the aquarium trade working with smoothhounds, leopards, starry smoothhounds, 7-gills, blacktips, bonnetheads, lemon, nurse and other constant swimming and sitting sharks and rays. But in the past years, I have keep the Sphyrna lewini, the Scallop Hammerhead shark at in- and outdoor ponds and huge aquariums. I like to have a discussion on the keeping of these sharks since they are in a way in danger where they come from. I cannot disclose the location of these sharks until a positive direction can be taken.

Here are the facts:

1. About 8,000-10,000 hammerhead pups are born every year from 300-500 female Hammerhead sharks.

2. Over 700 pups are caught, measured, weight and tag to be recaught at a later date. These pups grows only at a rate of 2"-3" anually in the wild. They only eat at the rate of 3% of their body weight every 2-3 days.

3. These hammerhead sharks are dying because of lack of food due to a number of factors, mostly directly related to polution. Diving in their area shows many dead pups due to starvation. An estimate of 4,000-6,000 do not survive their first year.

What I have done:

1. Hand collected these hammerhead pups at the size of 16"-24".

2. House them in saltwater ponds and pools for their acclimation and holding stage until a more permanent home is found for them. Mostly local hotels and private homes that have the adequate size ponds and aquarium.

What they need:

A. Since this species need to constantly swim, they need to be in an environment where they can swim and turn without any trouble. I have seen that a width of 36" or larger will house these sharks well at this size adequately for 3-5 years. At that time, they should not be bigger than 28" to 30" and need to be moved to a wider tank and become much more aggressive than their adolessence stage. They do eventually grow to a size of 12' (male) and 10' (female) my plans will be to release them back to the wild or find a much larger home to house them.

B. Feeding similar to the wild of every 2-3 days with 2-3 oz of food such as fresh shrimps, squids, and fresh fish fillet. Once a week, the food will have a vitamine additive.

For over a year now, we have keep 5 hammerhead pups in a 10' diameter small pool adequately. All 5 where in the 16" to 20" size when caught, the smallest of which had its umbilical cord present, 3 where males showing the clavicles, 3 are female. They have grown a bit and show signs of maturity. We introduce live bait fish for them to feed, but only the more matured ones are able to catch them usually at dawn or dust time.

I am open to any possitive comments in the persuit of keeping these hammerhead sharks.

Dean Trinh, Pres. of Aquatopusa.com

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ceeej31

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release to the wild isnt a very good idea, but i have to say that those sharks are pretty cool
 

PennReels84

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great job bro! keep it up! and if u have an extra pool and some sharks ill help ya out!
 

Gr8KarmaSF

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Wow!!!!

I see you are from SF. Have you seen the new Steinhart yet?
 

Zoodiver

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I've collected and kept Scalloped before. I love hammers, some of my favorite sharks. Good work on keeping them going so long.

Are you keeping them on flow through or closed loop?
What kind of growth rates are you seeing?

My biggest thing when keeping them was finding that the pups thrive when kept in groups - very similar to bonnets.
 

aquatopusa

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After recieving the first constructive response to my post, I can reply that yes, they do thrive best and swim together in group. If one should separate from the pack, it will have problems in feeding or have other major problems.

They hardly show any sign of growing in the length but show a clear girth increase during the time we have kept them, even though we give regular feeding and sometimes tend to overfeed (until they stop taking in any more food).

Filtration is a close loop system, with over 2000 lbs of live rubble rocks (more surface area) and huge skimmer/live sand filter.
 

Zoodiver

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I saw the same thing you commented with on the growth. They bulked up, but when compared to other sharks being kept at the same time (sharpnose, bonnets, Atl black tip reef, sandbar and bulls), the just didn't seem to get the length as quickly.

Do you have any info on lengths at various ages in the wild?

We ran them about 78-80F (give or take) on closed looped systems using sandfilters and fed somewhat similar to what you are saying. We did small amounts 4 times a week. As they grew, we added more food, but then less often with the times fed.
 

aquatopusa

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I have not found any studies on the various age and and length out in the wild because none of these were ever caught in enough rate to provide any consistent information. Monterey Aquarium who have also keep these scallops hammerhead have not been able to keep them long enough to get to any larger size. Talking to the director back in September, they were actually looking for larger 28"-36" size one but were not able to find any. I am confident that they would take any larger scallop hammerhead that were tank raised. We also notice that they are not aggressive at this stage and do not bother any of the other much smaller reef fish such as damsels, tangs, clownfish, or angels. They seem to only feed on food that have smell where they can locate and eat.

I also like to comment on the keeping of sharks in general. Keeping contant swimming sharks does require a different set up compared to fish or corals. They produce large amount of waste in a short period of time so the mechanical filtration is important for the fast removal of this waste such as a commercial size protein skimmer. The biological filtration takes care of the fast conversion of ammonia to nitrite and nitrate. The anaerobic bacteria of the live rocks takes care of the nitrate removal so having 2000 lbs of live rock seem to keep up to a dozen of these guys very adequately safe.

The last comment that I have is to all those who think we should not even touch these animals and leave them in the ocean. Well, this was said to the keeping of corals only about a decade ago when we were just starting to keep corals in home aquarium. Today, we have the knowledge and technology to keep and even propagate corals. I do not believe that the scallop hammerheads fit in this category of "leave them alone". I saw how many are dying out of starvation with every dive I do. I cannot leave them alone to let them die out to eventual extinction. I therefore take the stand that these animals need our help and we must learn much more about them in order to help. This is my opinion and I hope many others will take the time to understand what we are doing.
 

Zoodiver

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Georgia Aq bought in larger hammers and seemed to do well with them. They were part of the original display group of animals in the OV tank. But they did lose the original school of cownose rays to them.
 
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