The Life History and Energy Budget of \u3cem\u3eHippocampus erectus\u3c/em\u3e in Tampa Bay, Florida

Seahorses, genus Hippocampus erectus, are subject to large and continuously-growing international trade. Concerns with the effects of trade on seahorse population worldwide have led to their international protection by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). In order to manage seahorse populations, we first need to understand their basic biology. The purpose of this project was to establish an energy budget for Hippocampus erectus from Tampa Bay, Florida. A total of 108 specimens were collected throughout Tampa Bay from 2004 to 2007 using 21.3 m offshore seines and 6.1 m otter trawls. Those specimens were utilized to determine different components of the energy budget: size at maturity, feeding and nutrition within a captive environment, and metabolic rate. Seahorses collected in the study ranged in size from 4 mm to 160 mm, and were 0 to 4 years in age. Conventional methods of aging fish could not be applied to this species. Instead, an alternative method that involved sectioning vertebrae and using Scanning Electron Microscopy (SEM) to enumerate age-specific marks on vertebra was employed. Age data were then paired against length-weight charts to estimate age by length and mass. Length-frequencies were segregated by sex and compared to the growth data. No sex-specific differences were found. Fish reared in captivity were also used for nutrition, respiration, excretion analysis. Hippocampus erectus in captivity were calculated to have a resting respiration rate of 85.9 microliter O2/g/h and an excretion rate of 0.48 mmol NH3/g/h. The viscera of H. erectus and Artemia spp. were broken into protein and lipid content by caloric composition. The overall percentage of protein per seahorse was 11% and 17% by lipid concentration. Overall the sum of energy cost of H. erectus accounted for 81% of the total energy ingested