346 
Fishery Bulletin 106(4) 
Rose, 1999), especially footropes, bridles, and sweeps, to 
quickly evaluate mortality for Chionoecetes spp. with the 
use of RAMP estimators. Neither assessments of exo- 
skeletal injuries nor holding in cages or deck boxes will 
be required. Similarly, the sublethal and lethal effects 
of fishing conditions such as bottom type, water and 
air temperature, net packing, and time in air could be 
evaluated with a RAMP approach. Effects of soak times 
for pots and handling procedures could be assessed with 
the same tool. Also, with an increasing interest in the 
live market for crabs, the RAMP approach may be useful 
in perfecting shipping and holding procedures for the 
best possible live products. The largest direct benefit 
of RAMP approach will be to increase the scope and 
replication of experiments on gear and handling. More 
broadly, discard-related mortality is not constant, and 
we believe that this new approach will facilitate sub- 
stantial improvements in fishery models that incorporate 
mortality for crabs, lobsters, and other crustaceans that 
are routinely discarded at sea. 
Acknowledgments 
This project was funded in part by the National Oceanic 
and Atmospheric Administration Bycatch Reduction 
Program and the North Pacific Research Board. D. King 
and J. Smart prepared the recapture nets, S. McEntire 
assisted with electronics, S. McDermott loaned the deck 
boxes for holding crabs, and S. Walters and K.-H. Lee 
participated in the field study. We are grateful to Cap- 
tain R. Haddon and crew of the FV Pacific Explorer for 
assistance with tank set-ups and handling our uncon- 
ventional fishing gear. T. Hurst provided suggestions on 
statistical approach and anonymous reviewers helped to 
improve the manuscript. 
Literature cited 
Alverson, D. L., M. H. Freeberg, S. A. Murawski, and J. G. 
Pope. 
1994. A global assessment of fisheries bycatch and 
discards. FAO (United Nations Food and Agriculture 
Organization) Fish. Tech. Pap. 339, 235 p. 
Broadhurst, M. K., P. Suuronen, and A. Hulme. 
2006. Estimating collateral mortality from towed fishing 
gear. Fish Fish. 7:180-218. 
Carls, M. G., and C. E. O’Clair. 
1990. Influence of cold air exposure on ovigerous red 
king crabs (Paralithod.es camtschatica ) and Tanner crabs 
( Chionoecetes bairdi ) and their offspring. In Proceed- 
ings of the international symposium on king and Tanner 
crabs, p. 329-343. Univ. Alaska Sea Grant College 
Program, AK-SG-90-04, Fairbanks, AK. 
1995. Responses of Tanner crabs, Chionoecetes bairdi , 
exposed to cold air. Fish. Bull. 93:44-56. 
Coggins, L. G. Jr., M. J. Catalano, M. S. Allen, W. E. Pine III, 
and C. J. Walters. 
2007. Effects of cryptic mortality and the hidden costs 
of using length limits in fishery management. Fish 
Fish. 8:196-210. 
Crear, B. J., and G. N. R. Forteath. 
2001. Recovery of the western rock lobster, Panulirus 
cygnus, from emersion and handling stress: the effect of 
oxygen concentration during re-immersion. J. Shellfish 
Res. 20:921-929. 
Davis, M. W. 
2002. Key principles for understanding fish bycatch 
discard mortality. Can. J. Fish. Aquat. Sci. 59:1834- 
1843. 
2005. Behaviour impairment in captured and released 
sablefish: ecological consequences and possible substi- 
tute measures for delayed discard mortality. J. Fish 
Biol. 66:254-265. 
2007. Simulated fishing experiments for predicting 
delayed mortality rates using reflex impairment in 
restrained fish. ICES J. Mar. Sci. 64:1535-1542. 
Davis, M. W., B. L. Olla, and C. B. Schreck. 
2001. Stress induced by hooking, net towing, elevated 
sea water temperature and air in sablefish: lack of con- 
cordance between mortality and physiological measures 
of stress. J. Fish Biol. 58:1-15. 
Davis, M. W., and M. L. Ottmar. 
2006. Wounding and reflex impairment may be predic- 
tors for mortality in discarded or escaped fish. Fish. 
Res. 82:1-6. 
Davis, M. W., and C. B. Schreck. 
2005. Responses by Pacific halibut to air exposure: 
lack of correspondence among plasma constituents and 
mortality. Trans. Am. Fish. Soc. 134:991-998. 
Grant, S. M. 
2003. Mortality of snow crab discarded in Newfoundland 
and Labrador’s trap fishery: at-sea experiments on the 
effect of drop height and air exposure duration. Can. 
Tech. Rep. Fish. Aquat. Sci. 2481: vi + 28 p. 
Harrington, J. M., R. A. Myers, and A. A. Rosenberg. 
2005. Wasted fishery resources: discarded by-catch in 
the USA. Fish Fish. 6:350-361. 
Harris, R. R., and M. B. Andrews. 
2005. Physiological changes in the Norway lobster 
Nephrops norvegicus (L.) escaping and discarded from 
commercial trawls on the west coast of Scotland. 1. 
Body fluid volumes and haemolymph composition after 
capture and during recovery. J. Exp. Mar. Biol. Ecol. 
320:179-193. 
Kruse, G. H., D. Hicks, and M. C. Murphy. 
1994. Handling increases mortality of softshell Dunge- 
ness crabs returned to the sea. Alaska Fish. Res. Bull. 
1:1-9. 
O’Brien, J. J., D. L. Mykles, and D. M. Skinner. 
1986. Cold-induced apolysis in anecdysial brachy- 
urans. Biol. Bull. 171:450-460. 
Peduzzi, P. N., T. R. Holford, and R. J. Hardy. 
1980. A stepwise variable selection procedure for nonlin- 
ear regression models. Biometrics 36:511-516. 
Ridgway, I. D., A. C. Taylor, R. J. A. Atkinson, E. S. Chang, and 
D. M. Neill. 
2006. Impact of capture method and trawl duration 
on the health status of the Norway lobster, Nephrops 
norvegicus. J. Exp. Mar. Biol. Ecol. 339:135-147. 
Rose, C. S. 
1999. Injury rates of red king crab, Paralithodes camts- 
chaticus, passing under bottom-trawl footropes. Mar. 
Fish. Rev. 61(2):72-76. 
Rosenkranz, G. E. 
2002. Mortality of Chionoecetes crabs incidentally caught 
in Alaska’s weathervane scallop fishery. In Crabs in 
