Changes Through One Year in the Growth Rates of Tarpon, Megalops Atlanticus Valenciennes, Reared from Mid-Metamorphosis

Tarpon captured in autumn in Stage IIIA and measured on dates spaced through one year, grew from as little as 18-19 mm SL at the outset to 85-105 mm (Stage IIIB), with a weight increase as much as 39,000 per cent. Growth was maximal to late November, rates exceeding any recorded before for tarpon, but was minimal from then to mid-April, after which faster growth resumed. Curves of relative growth, growth rates, and annulus formation are examined in relation to ontogenetic differentiation, influences of intrinsic and extrinsic factors, and to the use of young tarpon as monitors of toxic pollutants, as growth-indicator, assay, and experimental animals.