Use of neurolipofuscin to determine age structure and growth rates of Caribbean spiny lobster Panulirus argus in Florida, United States

Abstract

We histologically determined lipofuscin content in eyestalk neural tissue to estimate the age and growth of Caribbean spiny lobster (Panulirus argus) in Florida, United States. Neurolipofuscin was measured from size‐stratified samples of 145 lobsters from the Florida Keys and 119 lobsters from the Dry Tortugas, the two main fishing areas in Florida. Modal analysis of the neurolipofuscin concentration frequency histograms suggested a relatively constant neurolipofuscin accumulation rate of 0.27% by volume (%VF) per year, which corresponded with the annual accumulation rate of 0.29%VF previously measured in the laboratory. Verification of the similarity of neurolipofuscin accumulation rates for lobsters in the field with previous laboratory studies indicates that neurolipofuscin concentration is suitable for estimating population parameters for P. argus. Neurolipofuscin‐based age estimates of lobster populations from the Florida Keys and Dry Tortugas, developed from Monte Carlo simulations of size‐frequency distributions, suggested that legal‐sized lobsters (>76.2 mm carapace length) in both areas were predominately 1–2 years old. Lobsters from the Florida Keys were consistently smaller for their age than those from the Dry Tortugas, suggesting that their growth is slower and that there may be little movement of lobsters between the two areas.