P1.30 Sunday, Jan. 4 Reproductive demographics of syngnathid fishes inhabiting a human-altered landscape MASONJONES, H.D.*; ROSE, E.; University of Tampa; University of Tampa firstname.lastname@example.org
Syngnathid fishes (pipefish and seahorses) are distinguished by their unusual brooding and mating systems. Due to their low mobility and high site fidelity, human alteration of the landscape may have dramatic impacts on their biology. This two year study investigated seasonal reproductive patterns of two syngnathid species, the gulf pipefish (Syngnathus scovelli) and the dwarf seahorse (Hippocampus zosterae) using a modified mark-recapture technique. Every 2-4 weeks, fish were collected via pushnet from 3 adjacent sites in Tampa Bay (FL), varying in their distance to open water within the system. This location was selected because of a nearby marina/housing construction project, which began six months into our study. Fish were marked, photographed, and released the same day to their collection sites. Our results indicate a large, flexible population with data for 5300 individuals. Reproductive demographics varied markedly across season in both S. scovelli and H. zosterae, with sex ratio cycling predictably in S. scovelli, but fluctuating dramatically in H. zosterae with season. Other sexual variables analyzed included habitat use by males and females (H. zosterae and S. scovelli), degree of sexual ornamentation in females (S. scovelli), and frequency of partial pregnancies in males (S. scovelli), all of which were found to vary across season. These results suggest the potential for environmental effects on the sexual selection landscape that may affect the availability of mates across season. Our results also indicate that population size and sexual ornamentation decreased and the frequency of partial male pregnancies increased across the study period, suggesting the possibility that degradation of environmental quality due to construction could have also impacted reproduction.