The Incredible Shrinking Weakfish

Weakfish have demonstrated large variation in maximum size over the last half century. Although there has been little or no decline in production of young-of-year weakfish, few weakfish currently reach the recreational minimum size of 330.2 mm (13 inches). Consequently, recreational landings (and commercial landings) in the Mid-Atlantic region of the Atlantic coast have declined greatly. In contrast, weakfish exceeding 750 mm (about 30 inches) were quite common in the 1970s and 1980s. Recent stock assessments (2006, 2009) concluded that natural mortality increased greatly beginning in 1996, reducing weakfish survival so that few reach larger sizes. Virtual population analysis using a constant value for natural mortality, however, produced biased estimates of fishing mortality, indicating that F had increased greatly beginning in 1996. Screening of potential factors producing the decline in survival and abundance of weakfish was unable to reject  the hypotheses that 1) the increased abundances of striped bass and spiny dogfish were probable causes of the weakfish decline, and 2) that an increase in the ratio of striped bass to Atlantic menhaden, the preferred prey of both adult weakfish and adult striped bass, was a probable cause of the weakfish decline. Weakfish life history is adapted to periods of low survival, because 90% of weakfish spawn at age 1, although they can live to  at least age 15 when environmental conditions are favorable.