Syngnathid Symposium 2011

Written By: | Date Posted: 11/12/2011 | 1 Comment |

Pygmy Seahorse

The the second Syngnathid Symposium was held the first week in November in Chicago at the Shedd aquarium. 92 delegates from all over the world gathered to discuss current issues with seahorses, sea dragons, pipefish and other syngnathids. Topics discussed were husbandry, challenges in breeding, keeping and obtaining these unique animals as well as conservation and research initiatives. Most attendees were from public aquariums, along with researchers, conservationists, a couple commercial interests, and me, a syngnathid nut.

I had the privilege to attend as an observer, blogger and general enthusiast and to learn more about the challenges those who work closely with seahorse, sea dragons, and the much forgotten pipefish. Topics ranged from the difficulties in sea dragon breeding to population dynamics of seahorses to at times loathing these difficult animals (even if in a loving way).

There were more topics covered than I could possibly share in a summary, but I want to share some of the highlights and the big issues, and breakthroughs revealed.

Health and Disease

Several issue still plague syngnathids. One of the biggest issues is mycobacter in captive populations. It seems to coexist without problems, but then there are flare ups when the disease become deadly. Or allows for a secondary infections such as vibrio to strike. This was quite interesting because the assumption by hobbyists is that vibrio is commonly to blame for infections. This is not what public aquariums are finding.

Uronema continues to be a pest, which can lead to vibriosis and other secondary infections. Some shy away from the use of malachite green, preferring chloroquine. A small number still use malachite green/formalin to treat.

There is still a lot of interest in bacterial vaccines, especially one for mycobacter since it is proving to be such a problem.

Gas bubble disease is still a problem for public aquariums, though much less though that it was when the first symposium took place. Most has been controlled through ensuring water isn’t supersaturated by either redesigning systems or effective off-gassing. However, a few cases seemed to be associated with vibrio infections. Acetazolamide is still used in many cases, but usually is not a long term fix, as the gas bubbles come back eventually.

There is strong evidence that the condition known as weak snick is caused by a nutritional deficiency, specifically vitamin e and selenium. Weedy seadragons with the condition were observed with muscle myopathy in the neck region. Once the deficiency was corrected, the animals were able to return to self feeding again. Further testing to confirm this issue in seahorses is planned.

Pathogenic fungii are showing up in seahorses and seadragons that attack the skin, gills, kidneys and other internal organs. These are thus far uncommon so there isn’t much treatment data. I found this especially interesting because I’ve had one, possibly two cases I’ve suspected fungal infections, and there was a confirmed case on seahorse.org. Hearing that there now clinical evidence of it in public aquariums makes me wonder how often it goes undiagnosed in cases where there is a mystery illness that isn’t responding to medications in hobbyist systems, as we very rarely have the money to do the type of testing to diagnose those issues.

Conservation

There is still a lot to be done on the conservation front, including understanding population dynamics and even to what extent various species range. The biggest threats to seahorses by far are Traditional Chinese Medicine, Trawling, and habitat loss/destruction. Traditional Chinese Medicine is still very problematic; more seahorses are being aquacultured for TCM but not nearly as many as are being taken from the wild.

Good news though, captive bred seahorses has become the dominant animals available in the aquarium hobby thanks to CITES, and better education means that aquarium hobbyists prefer the hardy captive bred individuals. So go hobbyists!

To this day, the biggest threat to seahorses is still Traditional Chinese Medicine. More seahorses are being aquacultured for TCM, but wild caught is still the predominant source for these animals.

Global warming is going to be a problem as well. There is hard evidence that H. algiricus is moving further north, and two males carrying hybrid H. algiricus x H. hippocampus fry were captured from the Canary Islands, which is north of their known range. There is a strong implication that this could cause species ranges to change and some species to die out all together if invaders can live in new waters.

Research

There are still huge gaps in our understanding of wild syngnathids, including how they fall taxonomic, how much their populations change over time, question about species definitions, and ranges. Wild H. abdominalis had a huge population reduction where the majority disappeared in a very short time, with no obvious cause. Now, the population is rebounding again and still no one knows why. Hippcampus zosterae’s population has been going up, which is unclear as to why as well. Anecdotal evidence suggests H. erectus might be going down as there have been fewer sitings in recent years.

Understanding the impacts of human habitat change was also a topic of paramount discussion. In Portugal, dredging of the Ria Formosa lagoon has substantially changed the habitat, and reduced the number of H. guttulatus found there. Research into artificial holdfasts for seahorse to help repopulate the areas where seagrass beds have been destroyed and can’t be replanted is one possibility.

One of the biggest surprises was the interest in studying the American seahorses more. It seems like even thought they’re right in our own backyards for the majority of attendees, there is still a lot of unknowns about habitats, and even species divisions. One of the workshops was to find aquariums that could help with field studies.

Another point that came up continually is employing the “citizen scientists” to help with reporting sightings of various species. It’s been done with sea dragons, and seahorses in the UK with a lot of success, so unsurprisingly there was a lot of interest in seeing how much further it could be taken.

Breeding

Raising seahorses and seadragons in captivity has come a long way since the last symposium in 1998. Weedy Seadragons, Phyllopteryx taeniolatus, have bred and had their young reared in captivity. In Leafy Seadragon, Phycodurus eques, breeding success remains elusive. Females have dropped eggs, males have had swollen tails and a few egg transfers have happened but the eggs were later dropped. This is the big challenge for aquariums in the coming years, but one that it seems many on the verge of cracking. The question becomes – who will be first?

Breeding and raising seahorses has become almost rote. The questions now are not how to raise seahorse fry but how to do it well. There were many discussions on the problems faced in raising them. One big piece of news was a histology study of seahorse fry with over-inflated swim bladders vs normal fry. For those seahorse breeders that have dealt with floaters this is big news. There is a paper about to be published on it so I won’t go into too much detail here, but the evidence found suggests that the damage progresses through the first 3 days post birth and is a physical problem with the gas bladder, suggesting even the “floaters” that appear a week or two after birth are something that can’t be prevented later in rearing.

Feeding of seahorse fry is also still of key interest. Various studies show that different food types and enrichment have a huge impact on survival. Unenriched brine shrimp shows poor survival rates as does rotifers enriched with just algaes, even isochrysis which is thought to be the best of the algaes for enrichment. Copepods are still the winner in survival rate, no surprise. One very interesting study showed that seahorse fry expended less energy hunting copepods even though copepods show more elusive escape behaviors than rotifers and brine shrimp.

Another study showed H. guttulatus fry did rather poorly when fed harpacticoid copepods (Tisbe sp.) vs. artemia and calanoid copepods (A. tonsa). The suggestion there was that Tisbe was just not available to seahorse fry because of their benthic nature. There has been a lot of speculation that any copepod is better than no copepods, and that at high densities, harpactacoids are bound to enter the water column and be available for feeding or anecdotal evidence of feeding off the sides of rearing vessels. Unfortunately, in this one study, that did not prove to be enough to positively affect survival.

And then there is the 24 hour feeding myth finally put to rest. One often cited piece of information regarding seahorse fry is that they can go without food for the first 24 hours and survive off their yoke sack. A starvation trial of one species showed that within the first 24 hours, lipids of newborn fry are totally depleted. This has long term implications on the survival of seahorse fry and suggests they need to eat immediately to keep up their energy reserves. That doesn’t necessarily preclude the possibility that seahorse fry could survive if then fed after the initial 24 hours, however it does suggest that there will be problems with growth and survival among those animals that are left to starve for that time. If it’s anything like clownfish, its entirely possible that they need the first 24 hours to learn how to properly hunt and strike at pray (though that is only speculation on my part.)

Record Keeping & Captive Genetic Diversity

Another issue public aquariums struggle with is record keeping with their animals. There isn’t a good software system that answer the needs of group animal keeping. Since most zoo record keeping systems are meant for larger animals that are easy to observe individuals, it proves problematic when you have a group of animals that may mate without knowing which animals are pairing up. There is work being done in that area, fortunately, and the symposium brought a renewed interest in studbooks to help keep track of different populations.

One cautionary tale that came of this was of H. capensis. In 2001, 17% of public aquariums had H. capensis in their collections. And at the time, they seemed the ideal animal for captivity. They bred easily, weren’t too fussy about the temperature of the water, didn’t seem to have a lot of trouble with general husbandry. But after a few years, many started succumbing to diseases and stopped breeding. Now only 2 aquariums are known to have them, both in South Africa. The issue, while still only a hypothesis, may have come about from the fact that there were only 12 founder animals, suggesting there had to be a lot of inbreeding to get the number of animals to the different aquariums. The same thing was happening to hobby aquarists at the same time. While no one knows if this is the problem for sure, it seems pretty likely, which is why aquariums are now so much more interested in making sure they can track captive populations and keep them genetically diverse.

Nutrition

Surprisingly, nutrition was a big question. Even though captive populations seem to do well on mysis shrimp, there was a lot of concern whether that was enough, and few aquarists spoke up over fat animals that were feed primarily P.E. mysis. Some aquariums are feeding small krill. Vitamin deficiency is a concern; as was highlighted by the concern over the “weak snick” vitamin e and selenium deficiency. Though the overall theme was no longer “what do we feed our animals?” but “What do we feed them for the longest lifespan and healthiest broodstock?”

One interesting thing to note is that many aquariums are going back to feeding live foods to their sea dragons. Even those animals comfortable eating frozen mysis are being offered live food in many places. The reason? Risk of infection. Dead mysis poses a health risk as they start to decay in the aquarium. Additionally, seadragons striking at the surface where dead mysis lay may injure themselves. Perhaps only a small scrape, but this can lead to bigger infections and problems down the road.

All and all, everyone was amazing. It was clear that everyone on hand had been touched by these amazing creatures and they had somehow weaved their way into the fabrics of their lives, and there was no question that this is what they were meant to be doing. There was so much information there, and it was a great gathering of minds were many people were able to connect and share their experiences and further the collective knowledge regarding syngnathids.

One Response to “Syngnathid Symposium 2011”

  1. robert Says:

    what temp best for seahorse

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