Munyandorero: Climate effects on Micropogonias undulcitus 
51 
dynamics in question and management implications. 
Hare et al.’s (2010) work provides guidance, serving as 
a preliminary study with respect to the recommenda- 
tion for age-structured models. 
The primary purpose of this study was to investi- 
gate whether biomass dynamic models (BDMs) could 
capture the MWET effects on the population dynamics 
of Atlantic Croaker off the U.S. Atlantic coast and to 
determine how this result effected the status determi- 
nation of the stock. Use of BDMs was aimed to address 
ASMFC’s need and Hare et al.’s (2010, p. 
461) suggestion regarding exploration of 
alternative models incorporating MWET, 
given that BDMs have the potential to 
track environmental perturbations (Keyl 
and Wolff, 2008). Unlike Hare et al. (2010), 
who dealt only with the “northern” stock of 
Atlantic Croaker, consistent with ASMFC, 3 
BDMs here incorporated relevant data 
for the coastwide stock in accordance with 
ASMFC. 1 Analyses relied upon a Bayes- 
ian state-space modeling framework with 
software from the Bayesian inference 
Using Gibbs Sampling (BUGS) Project. 
The influence of MWET on Atlantic 
Croaker stock biomass and productivity 
was investigated by two complementary 
approaches. First, process errors were in- 
troduced into a traditional BDM so that 
it could be determined whether those er- 
rors reflected environmental anomalies, 
assumed here to be largely dominated by 
changes in winter estuarine temperature 
(Joseph, 1972; Hare and Able, 2007; Hare 
et ah, 2010) and, hence, showed some re- 
lationship with MWET. Second, we inves- 
tigated the effects of explicitly incorporat- 
ing MWET into a BDM — that would yield 
effects on both population dynamics and 
management parameters. 
Materials and methods 
Data 
This study relied on fishery and survey 
data used in ASMFC 1 BDMs, except for 
the MRFSS CPUE because its develop- 
ment was questionable and because it was 
not considered a reliable index for stock 
biomass. The fishery-dependent remov- 
als (Fig. 1A) included 1) coastwide aggre- 
gates of commercial fishery landings and 
commercial finfish bycatch and discards 
(1972-2008), 2) coastwide recreational 
kills (1981-2008), 3) North Carolina scrap 
landings (1981-2008), and 4) SESTF by- 
catch (1972-2008). 
The NMFS, the Atlantic Coastal Cooperative Sta- 
tistics Program, and individual state fishery agencies 
have participated in collecting commercial landings 
data using various temporal resolutions and reporting 
requirements and processes. Reported commercial land- 
ings for all gear types (including the landed SESTF 
bycatch) were obtained from the Atlantic Coastal Co- 
operative Statistics Program Data Warehouse and, in 
3 cases, from individual state reports. The commercial 
finfish bycatch or discards were estimated for gill nets 
25000 
^ Commercial 
■ Scrap (bait) 
Recreational 
SESTF bycatch 
2008 
Figure 1 
Time series for the period of 1972-2008 of (A) commercial, recre- 
ational, and scrap (bait) fishery removals and bycatch of the south- 
eastern (North Carolina-east Florida) shrimp trawl fishery (SESTF) 
for Atlantic Croaker inhabiting the U.S. Atlantic coast; (B) biomass 
indices for Atlantic Croaker inhabiting the U.S. Atlantic coast, spe- 
cifically the National Marine Fisheries Service-Northeast Fisheries 
Science Center (NEFSC) fall index and the Southeast Area Monitor- 
ing and Assessment Program (SEAMAP) fall index; and (C) winter 
air temperature for Virginia as a proxy for minimum winter estua- 
rine temperature. 
