Geographic Variation in Life-History Traits of Black Sea Bass (Centropristis striata) During a Rapid Range Expansion

Abstract

The warming of the world's oceans has resulted in the redistribution of many marine species globally. As species undergo range shifts, the expanding edge of the population often experiences novel environmental and demographic conditions that may result in the emergence of variation in life-history strategies. The northern stock of black sea bass, Centropristis striata, has recently expanded its distribution poleward, into the Gulf of Maine. Management has struggled to keep pace with this rapid range shift, in part, because very little is known about the expanding population. We compared life-history traits of black sea bass collected from 2013 to 2016 from the northern most point of the historic range of the northern stock (southern Massachusetts) to those from two areas in the newly expanded range (northern Massachusetts and Maine). We found significant differences in size, diet, condition, maturity and sex ratio between black sea bass from southern Massachusetts and the Gulf of Maine. Overall, sea bass in the newly expanded range consumed a less diverse diet and their condition was lower, but they reached maturity at a younger age. We also found greater length-and age-at-maturity estimates from all regions combined compared to the most recent black sea bass stock assessment which includes data from Cape Hatteras, NC to southern Massachusetts. This study represents initial observations of life-history traits of sea bass in its newly expanded range in the Gulf of Maine, and suggests that these sea bass exhibit lifehistory strategies that differ from their southern counterparts within their historic range. Given these findings, the stock assessment for the Northeast U.S. Continental Shelf black sea bass stock may not be adequate for sea bass in the Gulf of Maine. Studies investigating the expanding edge of economically valuable fishery species are needed to aid in ongoing and future efforts to assess and manage their stocks.

Regional differences in energy allocation of black sea bass (Centropristis striata) along the U.S. Northeast Shelf (36°N to 42°N) and throughout the spawning season

“…High population density in the MA region could therefore negatively affect energy allocation and reproductive output. Finally, there could be dietary differences throughout the range as has been seen in NS C. striata from Southern New England and northward (McMahan et al ., 2020), affecting energetic intake and allocation. Altogether the low energetic status of MA fish could be because of a combination of abiotic and biotic factors.…”

“…Food limitation may not exist during the spawning season but energetic supply could be limited by nutritional quality. For example, NS C. striata in the Gulf of Maine had a less varied diet and, subsequently, lower condition than fish collected in Southern New England (McMahan et al ., 2020). Variation in the diet or reliance on single prey items can lead to notable effects on fish nutrition.…”

“…High population density in the MA region could therefore negatively affect energy allocation and reproductive output. Finally, there could be dietary differences throughout the range as has been seen in NS C. striata from Southern New England and northward(McMahan et al, 2020), affecting energetic intake and allocation. Altogether the low energetic status of MA fish could be because of a combination of abiotic and biotic factors.Although there were intraspecific differences across the distribution of NS C. striata, altogether their energy allocation patterns were suitable for spawning at higher latitudes where productivity is pulsed.…”

Climate-induced habitat suitability intensifies fishing-induced life-history variation of a migratory long-lived fish

“…First, continuous fishing pressure can erode fish biomass by substantially decreasing the proportion of large, old individuals. Still, STE-caused decline in maturity size and increase in mortality, may reduce reproductive output or the size of the breeding population (Johnston and Temple 2002, Morita et al 2005, McMahan et al 2020, and subsequent cause irreversible changes such as recruitment bottleneck, even extinction, to some populations, such as the collapse of Eastern blue groper, gemfish and blue-eye trevalla populations, following intense commercial fishing in Australia (Last et al 2011). Second, a decrease in the population size can also reduce variation (causing inbreeding and genetic abnormalities) and, therefore, restrict the potential for adaption (Langangen et al 2019).…”

Resilience of Black Sea Bass Embryos to Increased Levels of Carbon Dioxide

“…Historically, BSB have ranged from Massachusetts to the Gulf of Mexico, with the stock centered in the Middle Atlantic Bight (Roy et al 2012; Slesinger et al 2019). More recently, the northern stock of BSB has shifted northward into the Gulf of Maine, with the shift attributed to warming water temperatures (Bell et al 2015; Hare et al 2016; Kleisner et al 2017; McMahan et al 2020). Adults migrate seasonally from January through July for spawning, moving into coastal estuaries (e.g., Cape Hatteras, Chesapeake Bay, and the Delaware and Hudson River estuaries; Drohan et al 2007), where OA levels may be more variable than in the open ocean.…”