Meeting Abstract

P1.81  Friday, Jan. 4  Musculoskeletal determinants of pelvic sucker function in Hawaiian gobiid fishes: interspecific comparisons, allometry, and many-to-one mapping MAIE, T.*; SCHOENFUSS, H.L.; BLOB, R.W.; Clemson Univ.; St. Cloud State Univ.; Clemson Univ. maie045@gmail.com

Gobiid fishes possess a distinctive ventral sucker, formed from fusion of the pelvic fins, which can be used to adhere to a wide range of substrates including the vertical cliffs of waterfalls during upstream migrations in some species. Previous studies of waterfall-climbing species have found that pressure differentials and adhesive forces generated by the sucker increase with positive allometry as fish grow in size, despite isometry or negative allometry of sucker area. To produce such scaling patterns for pressure differential and adhesive force, waterfall-climbing gobies might exhibit allometry for other muscular or skeletal components of the pelvic sucker that contribute to its adhesive function. Using anatomical modeling, we evaluated the potential for allometric growth in the cross-sectional area, mechanical advantage, and force generating capacity of major protractor and retractor muscles of the pelvic sucker that help to expand the sealed volume of the sucker,,producing pressure differentials and adhesive force. We compared patterns for three Hawaiian gobiid species including a non-climber, a poor climber, and a proficient climber. Scaling patterns were similar for all species, typically exhibiting isometric or negatively allometric scaling for the muscles and lever systems examined. Although these scaling patterns do not help to explain the positive allometry of pressure differentials and adhesive force as climbing gobies grow, the best climber among the species we compared, Sicyopterus stimpsoni, does exhibit the highest mechanical advantage, muscular input force, and output force for pelvic sucker retraction at any body size, potentially facilitating its adhesive ability. NSF-IOS 0817911, 0817794.