139 
Climate-related hydrological regimes 
and their effects on abundance of juvenile 
blue crabs ( Ccillinectes sapidus) 
in the northcentraS Gulf of Mexico 
Guillermo Sanchez-Rubio (contact author ) 1 
Harriet M. Perry 1 
Patricia M. Biesiot 2 
Donald R. Johnson 1 
Romuald N. Lipcius 3 
Email address for contact author: guillermo.sanchez@usm.edu 
1 The University of Southern Mississippi 
Center for Fisheries Research and Development 
Gulf Coast Research Laboratory 
703 East Beach Drive 
Ocean Springs, Mississippi 39564 
2 The University of Southern Mississippi 
Department of Biological Science 
118 College Drive 
Hattiesburg, Mississippi 39406 
3 Virginia Institute of Marine Science 
The College of William and Mary 
Department of Fisheries Science 
P.O. Box 1346 
Gloucester Point, Virginia 23062 
Abstract — The abundance of juvenile 
blue crabs ( Callinectes sapidus ) in the 
northcentral Gulf of Mexico was inves- 
tigated in response to climate-related 
hydrological regimes. Two distinct 
periods of blue crab abundance (1, 
1973-94 and 2, 1997-2005) were 
associated with two opposite climate- 
related hydrological regimes. Period 
1 was characterized by high numbers 
of crabs, whereas period 2 was char- 
acterized by low numbers of crabs. 
The cold phase of the Atlantic Mul- 
tidecadal Oscillation (AMO) and high 
north-south wind momentum were 
associated with period 1. Hydrologi- 
cal conditions associated with phases 
of the AMO and North Atlantic Oscil- 
lation (NAO) in conjunction with the 
north-south wind momentum may 
favor blue crab productivity by influ- 
encing blue crab predation dynamics 
through the exclusion of predators. 
About 25% (22-28%) of the variability 
in blue crab abundance was explained 
by a north-south wind momentum in 
concert with either salinity, precipita- 
tion, or the Palmer drought severity 
index, or by a combination of the NAO 
and precipitation. 
Manuscript submitted 22 February 2010. 
Manuscript accepted 5 January 2011. 
Fish. Bull. 109:139-146 (2011). 
The views and opinions expressed 
or implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National Marine 
Fisheries Service, NOAA. 
Nonlinear oceanic-atmospheric oscil- 
lations have been linked to hydro- 
logical conditions in the continental 
United States. Individual and com- 
bined nonlinear oceanic-atmospheric 
oscillations, such as the Pacific 
Decadal Oscillation (PDO), Atlan- 
tic Multidecadal Oscillation (AMO), 
North Atlantic Oscillation (NAO), and 
El Nino Southern Oscillation (ENSO) 
have been shown to modulate Mis- 
sissippi, Atchafalaya, Pearl, and 
Pascagoula river flows in their lower 
basins (Sanchez-Rubio et ah, 2011). 
Discharge from the Mississippi and 
Atchafalaya rivers represents over 
90% of the total river discharge in 
Louisiana (Perret et ah, 1971). The 
Pascagoula and Pearl rivers account 
for more than 90% of the freshwater 
discharge into the Mississippi Sound 
(Eleuterius, 1978). High river flows in 
northern Gulf of Mexico (GOM) estu- 
aries have been linked to increased 
commercial landings of blue crabs 
(Callinectes sapidus ) in Texas (More, 
1969) and Florida (Wilber, 1994) and 
to both commercial landings and 
abundance of juvenile crabs (<40 
mm carapace width [CW]) in Louisi- 
ana (Guillory 2000). River discharge 
enhances wetland nursery areas by 
increasing the geographic extent of 
marsh-edge habitat and by provid- 
ing nutrients that facilitate growth of 
vegetation. The quantity and quality 
of coastal marsh habitat have been 
linked to the successful production of 
blue crabs. Flooding events directly 
influence the degree of accessibility 
of marsh habitats (Rozas and Reed, 
1993; Minello and Webb, 1997; Castel- 
lanos and Rozas, 2001). Vegetated and 
ephemeral structured habitats provide 
chemical cues for settlement, food, and 
refuge to juvenile crabs (Williams et 
al., 1990; Heck et ah, 2001; Rakocin- 
ski et ah, 2003). 
The blue crab is a conspicuous 
member of coastal ecosystems along 
the Atlantic and Gulf coasts and the 
species supports important recre- 
ational and commercial fisheries for 
both hard and soft crabs (Guillory et 
