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Life history, population dynamics and yield-per-recruit modeling of Atlantic croaker, Micropogonias undulatus, in the Chesapeake Bay area
| Content Provider | Semantic Scholar |
|---|---|
| Author | Barbiéri, Luiz R. R. |
| Copyright Year | 1993 |
| Abstract | Otoliths, scales, dorsal spines, and pectoral fin rays, of Atlantic croaker, Micropogonias undulatus, were compared for legibility of presumed annual marks and precision in repeated readings, to determine the best hard part for ageing. Marks on transverse otolith sections were easiest to read and showed the best agreement between readings. Atlantic croaker collected from commercial catches in Chesapeake Bay and in Virginia and North Carolina coastal waters during 1988-1991 were then aged using otolith sections. Ages 1-8 were recorded, but eight-year-old fish were rare. Marginal increment analysis showed that for ages 1-7 annuli are formed once a year during the period April-May. Otolith age readings were very precise, with percent agreement within and between readers greater than 99%. Observed lengths-at-age were highly variable and showed a rapid decrease in growth after the first year. Observed lengths for ages 1-7 showed a very good fit to the von Bertalanffy growth model (r2=0.99; n=753) . No differences were found between sexes. Total annual instantaneous mortality (Z) estimated from maximum age and from a catch curve of combined Chesapeake Bay catches ranged from 0.55 to 0.63. Atlantic croaker are multiple spawners with asynchronous oocyte development and indeterminate fecundity. Mean length at first maturity for males and females was 182 and 173 mm TL, respectively. More than 85% of both sexes were mature by the end of their first year and all were mature by age 2. Spawning extends over a protracted period (July-December), but individual fish spawn for only 2-3 months. Spawning starts in Chesapeake Bay and continues offshore and south as Atlantic croaker migrate from the estuary. However, some individuals seem to complete spawning in estuarine waters. Seasonal fluctuations in sex ratios suggest that males start leaving the estuary earlier than females. A high incidence of atretic advanced yolked oocytes in spawning females suggests that a surplus production of yolked oocytes is part of Atlantic croaker reproductive strategy. Females would hydrate and spawn more or less of these yolked oocytes depending on environmental conditions. Yield-per-recruit modeling results indicated that, over a likely range of natural mortality values, present levels of harvest in Chesapeake Bay are below the maximum potential yield-per-recruit. Results from this study do not indicate the existence of a group of larger, older fish in the Chesapeake Bay region and suggest that the hypothesis of a different population dynamics pattern for Atlantic croaker north and south of North Carolina, should be reevaluated. Life history, population dynamics and yield-per-recruit modeling of Atlantic croaker, Micropogonias undulatus, in the Chesapeake Bay area GENERAL INTRODUCTION The Atlantic croaker, Micropogonias undulatus (Linnaeus) ranges from Cape Cod, Massachusetts to the Bay of Campeche, Mexico (Welsh and Breder 1923, Chao 1978). Although not common north of New Jersey (Welsh and Breder 1923, McHugh 1981), it represents one of the most abundant inshore demersal species of the Atlantic and Gulf of Mexico coasts of the United States (Joseph 1972, Chittenden and McEachran 1976). The Atlantic croaker is a seasonal migratory species. In the Middle Atlantic region adults move north into Chesapeake Bay waters in the spring, and offshore and south in the fall to overwinter along the coasts of Virginia and North Carolina (Pearson 1932, Wallace 1940, Haven 1959). However, details of these migratory patterns are still unknown. Spawning is reported to take place over the continental shelf (Colton et al. 1979, Morse 1980, Norcross and Austin 1988, Norcross 1991), over a large area that may include waters near the mouth of the Chesapeake Bay (Welsh and Breder 1923, Pearson 1941). Post-larvae and small juveniles recruit into the Chesapeake Bay and its major tributaries in the fall and stay until the following year, |
| File Format | PDF HTM / HTML |
| DOI | 10.25773/v5-43sa-dd63 |
| Alternate Webpage(s) | https://scholarworks.wm.edu/cgi/viewcontent.cgi?article=2128&context=etd |
| Alternate Webpage(s) | https://doi.org/10.25773/v5-43sa-dd63 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
