Seahorse recovers quickly from transit stress


Pot-belled seahorses recover as quickly from transport stress as other fish, suggesting that extra precautions are unnecessary when shipping the species.

Scientists from the University of Otago in New Zealand studied the Pot-bellied seahorse, Hippocampus abdominalis, to determine whether the fish developed a "fish or flight" response during shipping, and what physiological changes took place.

During experiments, the seahorses were exposed to an acute stressor (being exposed to air for one minute) and a chronic stressor (being confined or transported).

By monitoring the levels of stess substances, such as cortisol, glucose and lactate, which are present at greater levels in the plasma during stress, the scientists were able to determine the seahorses current stress levels and their rate of recovery.

Pot-bellied seahorses showed little "fight or flight", with no increase in cortisol, glucose or lactate when they were exposed to the acute stress of air exposure.

However, chronic stress from shipping did cause the fish to release stress substances. Cortisol levels rose to 77ng ml and glucose levels to 7nM, but both dropped to pre-stress levels of 4ng ml and 4mM within six hours.

The authors said: "Recovery from chronic stress thus fitted the teleost paradigm, i.e. plasma levels of cortisol and glucose returned to pre-stress values in c. 6 h during recovery from a chronic stressor. The seemingly rapid return to homeostasis suggests that special precautions, over and above normal procedures, may not be required for long-distance transportation of pot-bellied seahorses."

For more information see the paper: KA Wright, CMC Woods, BE Gray, PM Lokman (2007) - Recovery from acute, chronic and transport stress in the pot-bellied seahorse Hippocampus abdominalis. Journal of Fish Biology 70 (5), 1447"1457.