Reproduction, first-year growth, and expansion of spawning and nursery grounds of black sea bass (Centropristis striata) into a warming Gulf of Maine

Abstract

The black sea bass (Centropristis striata) is extending its range northward, into a warming Gulf of Maine. Here, we plot the geographic distribution of specific life stages to examine whether spawning and settlement, and therefore productivity, are extending northward. In order to align these life stages with the correct sampling season, we first resolve confusion about the spawning seasonality of this species, by collecting age-0 individuals from coastal waters of southeastern Massachusetts (Buzzards Bay and Nantucket Sound) and aging them by using daily otolith microincrements. Wild-caught age-0 fish (n=381), ranged in size from 32 to 88 mm total length (mean: 53 mm {[}standard deviation (SD) 11]), and in age from 50 to 129 d old (84 d {[}SD 16]). They hatched from May 2 to July 21 (June 6 {[}SD 14 d]), and grew at linear rates from 0.32 to 1.22 mm/d (0.65 mm/d {[}SD 0.15]). The literature and two 40-year trawl surveys confirm that black sea bass have spawned in Buzzards Bay and Nantucket Sound since the 1880s. Farther north, in the southern Gulf of Maine, spawning has likely occurred in the last 15 years. Settlement has increased about 1 degrees N latitude over the recent 4 decades in association with warming sea temperatures in the southern Gulf of Maine.