A Life History Assessment on the Reproduction and Growth of Striped Mullet, Mugil cephalus, in North Carolina

Abstract

The striped mullet, Mugil cephalus, has supported a commercial fishery in North Carolina since the 1800s and today ranks in the top ten of commercially valuable fin- fisheries in the state worth over a million dollars annually. The species is a direct link between lower and higher trophic levels and thus serves an important role in the food web. Despite striped mullet's biological and economic importance, basic life history data from North Carolina are limited and the stock status is unknown. Objectives of this study were to describe striped mullet growth, reproductive seasonality, size and age at maturity, and fecundity. Monthly samples of striped mullet were collected using both fishery independent and dependent sampling strategies throughout North Carolina. Sagittae otoliths were removed and sectioned for age and growth analyses. Gonads were fixed and histologically prepared for maturity indices and fecundity estimation. Length was highly variable within age classes. Regional growth differences within North Carolina were found as fish collected from the southern sampling regions were smaller at age and lived longer than fish from the northern regions. Growth models suggest growth rates in North Carolina were greater than other areas in the species' range. Based on the presence of recently post-spawned fish and gonadal development, striped mullet spawn between late September and December. The collection of a hydrated female less than 1 km from an inlet, coupled with the presence of post-ovulatory follicles from fish sampled within the estuary, provided evidence for near-shore spawning. Males matured at a smaller length (L50) than females, 283 mm and 324 mm fork length, respectively. Fecundity correlated well with fork length (r2=0.88) and body weight (r2=0.91), and ranged from 1193 to 2535 eggs per gram of eviscerated body weight. This study provides the first life history assessment of striped mullet reproduction and growth from North Carolina and shows differences in growth, maturity, spawning location, reproductive seasonality, and fecundity compared to other areas in the species' range.