46 
additional site. Although one of the red king crab sites 
was in a closed area, both such sites were similar in 
depth and substrate to areas where Bering Sea ground- 
fish fisheries encounter that species. If <7 individuals 
of a species were captured in one of the nets, crab as- 
sessments for that species were not used in the analy- 
sis. Tow tracks were arranged to minimize crossing the 
trawl tracks of previous tows and to keep such cross- 
ings close to perpendicular, to limit areas of overlap. 
Track crossings made up <1% of study tows. We also 
maximized the time elapsed between such crossings 
(always more than 1 day) so that immediate mortali- 
ties from earlier exposure would be easily recognizable. 
Upon recovery, the recapture codend was opened 
and all Chionoecetes crabs in 2008, or red king crab 
in 2009, were removed and sorted by species and sex 
(Jadamec et ah, 1999). To use our project’s resources 
most efficiently, we used a 2-stage sampling procedure 
in which all of the subject animals were assessed im- 
mediately for selected condition attributes and a small 
sample of those subjects was held long enough to relate 
those attributes to eventual mortality rates. 
All Chionoecetes crabs were assessed for the pres- 
ence of the 6 reflex responses described in Stoner et 
al. (2008): leg flare, leg retractions, chela closure, eye 
retraction, mouth closure, and kick. For red king crab, 
the leg retraction reflex test was replaced with a test 
of antennae movement response. Antennae, minuscule 
in snow or southern Tanner crabs, were quite active 
and responsive for red king crab, providing a more sen- 
sitive reflex response. As in the Stoner et al. (2008) 
eye and mouth tests, the antennae were manipulated 
and responsive movements were recorded as a positive 
response. 
Assessments were limited to presence or absence 
of reflexes, there was no evaluation of reflex strength. 
This simplification allowed for rapid assessments and 
reduced any ambiguity or observer variation (Stoner 
et al., 2008). Initial scans separated unimpaired crabs 
from those crabs with an injury or at least one reflex 
missing. Missing reflexes and any injuries were record- 
ed. Reflex scores indicated the number of impairments; 
a score of 0 indicated an unimpaired crab, and a score 
of 6 indicated a moribund crab with no reflexes pres- 
ent. Sex and shell condition for all crabs and carapace 
width for the 2 Chionoecetes spp. and carapace length 
for red king crab were recorded. Shell conditions (Jada- 
mec et ah, 1999) included soft shell (shell soft and pli- 
able), new hard shell (firm to hard shell that lacked 
wear or encrustment), old shell (wear and encrustment 
present) and very old shell (extensive signs of shell 
wear and encrustment). Catch processing generally 
took less than 15 min, and crabs were held in seawater 
when they were not being processed. 
For each crab species, specimens representing each 
reflex score were tagged and held to estimate the re- 
lationship between reflex score and delayed mortality. 
Collections of snow and Tanner crabs in 2008 supple- 
mented the RAMP results of the 2007 pilot study. Selec- 
Fishery Bulletin 1 1 1 (1) 
tion of crabs for holding emphasized those with reflex 
scores from 1 to 5, categories that had lower observed 
numbers in the earlier study. Holding procedures were 
identical to those of Stoner et al. (2008), with -900 L 
on-deck tanks, supplied with seawater flow >20 L/min. 
Crabs were assessed daily, and those crabs that died 
were recorded and removed. 
Early in the 2009 work, it became apparent that 
many of the red king crabs with no reflex impairments 
but apparent injuries were dying. This outcome indi- 
cated that fatally injured red king crab were not as 
likely to lose reflexes as were the Chionoecetes crabs 
and led us to adapt the full RAMP approach so that 
all red king crab that had either a missing reflex or an 
apparent injury were held. To ascertain how commonly 
fatal damage was completely hidden, 367 uninjured 
crabs displaying all reflexes were held. 
Our estimator of the probability of mortality for 
crabs with each reflex score was the proportion of held 
crabs with that score that died for each species. To 
estimate overall mortalities, the proportions of crabs 
in each reflex class were multiplied by the probability 
mortality of that reflex class and summed (Eq. 1): 
m c = S r=0 to 6^r * (1) 
where m c = the mortality estimate for a species in 
catch c; 
m r = the mortality probability from the RAMP 
for that species for reflex score r ; and 
p rc = the proportion of that species from catch c 
with reflex score r. 
For red king crab, this formula was modified to use 
the actual mortality outcomes of the injured and reflex- 
impaired crabs, all of which were held for observation 
(Eq. 2): 
m c = (m u * p uc ) + mjN ic )*p ic ), (2) 
where D IC = the number of impaired or injured crabs 
that died from catch c; 
N ic = the number of injured or impaired crabs in 
catch c; and 
m and p have the same meaning as in Equation 
1, except that i refers to injured or im- 
paired crabs and u refers to those crabs 
that were uninjured with all reflexes 
present. 
To estimate mortality for crabs that encountered a por- 
tion of the trawl, mortalities (m c ) for all catches from 
recapture nets installed in that area were averaged 
and weighted for the number of crabs in each catch. 
To correct mortality estimates for handling dam- 
age, we assumed that gear and handling mortalities 
were independent and sequential. That is, where both 
processes occurred together in the recapture catches 
( m g +h)> the S ear mortality (m g ) occurred first and only 
those crabs not killed by the gear (1 - m g ) were vulner- 
able to handling mortality (m h , estimated as the mor- 
