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Fishery Bulletin 111(3) 
by several historical and more recent tagging studies. 
A study that examined fish tagged and released off the 
northeastern coast of the United States from 1942 to 
1949 concluded that groups were relatively localized 
and exhibited short seasonal migrations. Most tagged 
fish were recovered within 80 km of the release site and 
little mixing was observed between fishing grounds, 
except for frequent movement from the Mid-Atlantic 
Bight to the waters of southern New England (Royce et 
al., 1959). Lux (1963) confirmed these observations and 
concluded that groups ofYellowtail Flounder move sea- 
sonally within fishing grounds, and a small amount of 
seasonal mixing occurs among groups. More recent tag- 
ging studies ofYellowtail Flounder in Canadian waters 
have confirmed the sedentary nature of this species. 
Fish tagged from 3 studies on the Grand Bank, Cana- 
da, traveled an average of 59 km (Walsh and Morgan, 
2004). A recent summary of all previously published 
studies that detailed Yellowtail Flounder movements 
off the northeastern United States indicated 95% resi- 
dence in current stock areas (Cadrin, 2010). 
The cooperative Yellowtail Flounder tagging study 
described in this article was designed to address sourc- 
es of uncertainty in Yellowtail Flounder stock assess- 
ments. Two objectives of this study were to provide 1) 
estimates of mortality independent of mortality esti- 
mates from current Yellowtail Flounder stock assess- 
ments and 2) extensive release and recovery informa- 
tion and documentation of movement of fish between 
stock areas. 
Materials and methods 
The general approach to tagging in this study involved 
a sampling design with geographic coverage that repre- 
sented the entire Yellowtail Flounder resource off New 
England. All phases of the proposed research, from the 
field protocol to public outreach, were developed co- 
operatively with New England groundfish fishermen. 
We contracted commercial fishermen and their vessels 
to work with scientists to tag and release fish in all 
stock areas. The geographic design was developed on 
the basis of fishing areas, with releases in each area 
proportional to values of relative abundance of Yellow- 
tail Flounder from groundfish surveys conducted by the 
Northeast Fisheries Science Center. The field protocol 
and analytical design were considered during peer re- 
view to be valid approaches to meet the objectives of 
this tagging study (NEFSC 2 ). 
Fish were captured with commercial otter trawls 
or gillnets with large mesh (16.5 cm) and relatively 
short trawl tows (30 min) or gillnet sets (<6 h). Yel- 
lowtail Flounder were identified by using Collette and 
Klein-MacPhee (2002). All legal-size fish (>33 cm in 
fork length) in viable condition, and some sublegal-size 
fish from tows in low-density areas, in the southern 
New England-Mid-Atlantic stock area were tagged 
with Petersen disc tags (22-mm in diameter). Viability 
was classified as excellent, good, or poor. Excellent fish 
exhibited body flexion and operculum or mouth move- 
ment, and no apparent damage from capture. Good 
fish also exhibited activity but had minor damage (e.g., 
scale loss, minor abrasion, and net marks). Poor fish, 
which exhibited no activity and had major abrasions 
or bleeding, were not tagged. Fish were released during 
the spawning season (May-August), with the exception 
of 1% of the releases, which occurred in the autumn 
of 2003. 
Tags were collected from fish recaptured from a 
year-round commercial fishery with some seasonal 
geographic closures. The reward system for reporting 
recaptures included a $1000 lottery for all returned 
tags and 280 high-value ($100) rewards. The outreach 
system involved reward posters, brochures, a website 
(http://www.cooperative-tagging.org), annual letters to 
Yellowtail Flounder fishermen, press releases, and a 
toll-free phone number. Patterns of tag-recovery rates 
were analyzed statistically with contingency tables (G- 
test; Sokal and Rohlf, 1995) of frequencies of releases 
and reported recaptures by sex, size, condition code, 
and damage code. 
To analyze the Yellowtail Flounder tagging data, 
Program MARK was used to fit multiperiod tagging 
models (White and Burnham, 1999). Program MARK 
facilitates the application of various types of mark- 
recapture models and estimates model parameters 
through the use of maximum likelihood. Brownie-type 
dead-recovery models (Brownie et al., 1985) were used 
to estimate the probability ofYellowtail Flounder sur- 
vival ( S ) and a recovery rate probability if). Recovery 
rate in this study was a compound parameter that rep- 
resented the probabilities that a tagged fish was cap- 
tured, the tag was retrieved, and the tag was reported. 
The model assumes that the probabilities of survival 
and recovery are the same for all marked animals 
and that tagging is instantaneous during sampling 
occasions. 
A preliminary analysis, in which alternative tag- 
ging models with time-steps over different temporal 
scales (weekly, monthly, biannual and annual) were 
examined, indicated that the data were best suited for 
models with a monthly time step. Recovery data were 
entered into Program MARK with a classic recovery 
matrix format (Brownie et ah, 1985; White and Burn- 
ham, 1999). The recovery matrix was examined with 
a suite of models that exhibited both time-dependent 
and constant survival, as well as time-dependent and 
constant recovery rate. Sex was included in the model 
as a group effect on survival and recovery rate. In addi- 
tion, commercial catch was used as a proxy for fishing 
effort and was explored as a covariate on recovery rate 
in multiple models. Matrices of expected values were 
developed for each model, and recoveries were modeled 
as multinomial random variables. Parameters were es- 
timated with maximum likelihood estimation. 
Akaike’s information criterion (AIC) was used to 
rank and select the model that achieved an optimal 
