305 
Abstract — Assessing the vulner- 
ability of stocks to fishing practices 
in U.S. federal waters was recently 
highlighted by the National Marine 
Fisheries Service (NMFS), National 
Oceanic and Atmospheric Adminis- 
tration, as an important factor to 
consider when 1) identifying stocks 
that should be managed and protected 
under a fishery management plan; 2) 
grouping data-poor stocks into rel- 
evant management complexes; and 
3) developing precautionary harvest 
control rules. To assist the regional 
fishery management councils in deter- 
mining vulnerability, NMFS elected 
to use a modified version of a pro- 
ductivity and susceptibility analy- 
sis (PSA) because it can be based 
on qualitative data, has a history of 
use in other fisheries, and is recom- 
mended by several organizations as 
a reasonable approach for evaluating 
risk. A number of productivity and 
susceptibility attributes for a stock 
are used in a PSA and from these 
attributes, index scores and mea- 
sures of uncertainty are computed 
and graphically displayed. To dem- 
onstrate the utility of the resulting 
vulnerability evaluation, we evalu- 
ated six U.S. fisheries targeting 162 
stocks that exhibited varying degrees 
of productivity and susceptibility, and 
for which data quality varied. Overall, 
the PSA was capable of differentiat- 
ing the vulnerability of stocks along 
the gradient of susceptibility and 
productivity indices, although fixed 
thresholds separating low-, moderate-, 
and highly vulnerable species were 
not observed. The PSA can be used 
as a flexible tool that can incorporate 
regional-specific information on fish- 
ery and management activity. 
Manuscript submitted 12 August 2009. 
Manuscript accepted 22 April 2010. 
Fish. Bull. 108:305-322 (2010). 
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. 
Using productivity and susceptibility indices 
to assess the vulnerability 
of United States fish stocks to overfishing 
Wesley S. Patrick (contact author ) 1 
Paul Spencer 2 
Jason Link 3 
Jason Cope 4 
John Field 5 
Donald Kobayashi 6 
Peter Lawson 7 
Todd Gedamke 8 
Ernie Cortes 9 
OJaw Ormseth 
Keith Bigelow 6 
William Overholtz 3 
Email address for contact author: Wesley.Patrick@noaa.gov 
6 Pacific Islands Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
2570 Dole Street 
Honolulu, Hawaii 96822 
1 Office of Sustainable Fisheries 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
1315 East-West Highway 
Silver Spring, Maryland 20910 
2 Alaska Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
7600 Sand Point Way 
Seattle, Washington 981 1 5 
3 Northeast Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
166 Water Street 
Woods Hole, Masssachusetts 02543 
4 Northwest Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
2725 Montlake Boulevard East 
Seattle, Washington 98112 
5 Southwest Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
110 Shaffer Road 
Santa Cruz, California 95060 
7 Northwest Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
2030 South Marine Science Drive 
Newport, Oregon 97365 
8 Southeast Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
75 Virginia Beach Drive 
Miami, Florida 33149 
9 Southeast Fisheries Science Center 
National Marine Fisheries Service 
National Oceanographic and 
Atmospheric Administration 
3500 Delwood Beach Road 
Panama City, Florida 32408 
The need to ascertain the status of fish 
stocks is a common issue for fisheries 
management agencies the world over. 
Stock assessments are usually man- 
dated by various national or interna- 
tional laws and frequently include an 
evaluation of a stock’s current biomass 
and fishing mortality rate compared to 
some reference level, often maximum 
sustainable yield (MSY). Because of 
the data requirements for evaluating 
the status of stocks, however, a large 
proportion of the world’s fishery man- 
agers and scientists lack the ability to 
adequately assess the status of their 
stocks (Mora et al. 2009). In the past, 
many of these data-poor stocks have 
been managed by using a “harvest 
control rule” that was based on the 
overfishing limit for, and biomass of, 
the stock. However, with little knowl- 
edge of a stock’s status it is difficult 
to appropriately apply precautionary 
management (Restrepo and Powers, 
