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CA Thresher Shark/Swordfish Drift Gillnet Fishery (>/=14 in mesh)

Current Classification on 2017 LOF

Category I
Estimated Number of Participants 18
Target Species Thresher shark, swordfish, and mako shark are ~90% of the catch; swordfish, common thresher, pelagic thresher, bigeye thresher, shortfin mako, blue shark, albacore, tunas, dorado, groundfish, coastal pelagics, crab.  Other species commonly caught include opah, big-eye thresher, louvar, barracuda, Pacific bonito, mahi mahi, white seabass, and tunas.
Applicable Take Reduction Plans Pacific Offshore Cetacean TRT
Observer Coverage Estimated observer coverage from 1990- 2008 was: 4%, 10%, 14%, 13%, 18%, 16%, 12%, 23%, 18%, 20%, 23%, 20%, 22%, 20%, 21%, 21%, 19%, 16%, 13.5%, respectively.
Marine Mammal Species/Stocks Killed or Injured Bottlenose dolphin, CA/OR/WA offshore;
California sea lion, U.S.;
Humpback whale, CA/OR/WA;
Long-beaked common dolphin, CA;
Minke whale, CA/OR/WA;
Pacific white sided dolphin, CA/OR/WA;
Northern elephant seal, CA breeding;
Northern right whale dolphin, CA/OR/WA;
Risso’s dolphin, CA/OR/WA;
Short-beaked common dolphin, CA/OR/WA;
Short-finned pilot whale, CA/OR/WA;
Sperm whale, CA/OR/WA(1)

^ Number of participants estimates are based on state and federal fisheries permit data.  The estimated number of participants is expressed in terms of the number of active participants in the fishery, when possible.  If this information is not available, the estimated number of vessels or persons licensed for a particular fishery is provided.  If no recent information is available on the number of participants, then the number from the most recent LOF is used.  NMFS acknowledges that, in some cases, these estimations may be inflating actual effort.  

*Observer coverage levels include the latest information reported in the most current final Stock Assessment Report (SAR)

(1) Indicates the stock or species is driving the classification of the fishery 

Note: Current classification based on final LOF, no proposed changes are reflected in this table.

Basis for Current Classification

The total annual mortality and serious injury of sperm whales (CA/OR/WA) is more than 50% of the stock's Potential Biological Removal (PBR) level. 


Ranges from the U.S./Mexico border north to waters off of Oregon.  The fishery is subject to season-area closures: From February 1-April 30 effort must be more than 200 nmi from shore; May 1-August 14 must be more than 75 nmi from shore; August 15-January 31 must be more than 12 nmi from shore.  Majority of the effort occurs in October-December.  A season-area closure to protect leatherback sea turtles was implemented in August 200, prohibiting drift gillnet fishing from August 15-November 15 in a set area from Point Sur, CA, to the OR coast.  Another season-area closure exists south of Point Conception and east of W120° from June-August during El Nino years to protect loggerhead turtles.

Gear Description

Gear consists of a 1,000 fathom (1,829 m) gillnet with stretched mesh size from 18-22 in (45.7-56 cm), with a 14 in (35.6 cm) minimum.  The net is set at dusk and allowed to drift during the night, with the fishing vessel typically attached at one end of the net.  The soak duration is typically 12-14 hours depending on length of the night.  Net extender lengths of a minimum 36 ft (11 m) became mandatory for the 1997-1998 fishing season, and the use of acoustic warning devices (i.e., pingers) became mandatory October 28, 1997, significantly decreasing cetacean entanglement.


This fishery is a limited entry with seasonal closures and gear restrictions, managed under the Highly Migratory Species Fisheries Management Plan (FMP) and by regulations under the Pacific Offshore Cetacean Take Reduction Plan (POCTRP).  The FMP includes a series of seasonal and area closures originally promulgated by CA Department of Fish and Game.  The POCTRP including a requirement for pingers on drift gillnets, requirement that extenders (buoy lines) be at least 36 feet long, and vessel captains attend skipper education workshops through NMFS Southwest Regional Office.  OR restricts landing to swordfish only.  Gear prohibited off of the WA coast. 


Historical Information

Original Category (Year added to the LOF) I (1996)
Original Number of Participants 150
Basis for Original Classification Observer data from 1991-1993 indicated that the total annual mortality and serious injury of Pacific sperm whale was more than 50% of the PBR (PBR=1).
Past Names CA/OR thresher shark/swordfish drift gillnet (≥14in. mesh) fishery (until 2011);
CA/OR thresher shark/swordfish drift gillnet fishery (until 2003)
Species/stocks historically documented as killed or injured (but not currently on the list) Baird's beaked whale (CA/OR/WA);
Cuvier's beaked whale (CA/OR/WA);
Dall's porpoise (CA/OR/WA);
Fin whale (CA/OR/WA);
Gray whale (ENP);
Killer whale (ENP offshore);
Mesoplodont beaked whale (CA/OR/WA);
Northern fur seal (San Miguel Island);
Pygmy sperm whale (CA/OR/WA);
Short-finned pilot whale (CA/OR/WA);
Steller sea lion (Eastern U.S.);
Striped dolphin (CA/OR/WA)


Timeline of Changes

  • Added short-finned pilot whale (CA/OR/WA).
  • Estimated number of participants updated from 19 to 18.
  • Estimated number of participants updated from 25 to 19.
  • Added minke whale (CA/OR/WA).
  • Reclassified as Category I. Two sperms whales were observed entangled in this fishery in 2010.  One whale was dead and the other seriously injured.  These were the first observed entangled sperm whales in this fishery since 1998.  Based on the most recent five years of available information, the average mortality and serious injury of sperm whale (CA/OR/WA) in this fishery is 3.2 whales per year, which is greater than 213% of the PBR level of 1.5.
  • Added sperm whale (CA./OR/WA) and included a superscript “1” following the stock.
  • Added bottlenose dolphin (CA/OR/WA offshore).
  • Removed the superscript “1” from humpback whale (CA/OR/WA).
  • Estimated number of participants updated from 45 to 25.
  • Reclassified as Category II.  NMFS received a mortality/injury self-report from a fisherman indicating a humpback whale was entangled in 2009 during operations of this fishery.  Based on the information in this self-report and follow-up discussion with the reporting fisherman, NMFS Science Center staff determined this whale to be seriously injured because the animal was cut loose and released alive with entangling and trailing gear.  The location of the entanglement off of Southern CA indicates the animal was most likely part of the CA/OR/WA stock of humpback whales.  The total annual mortality and serious injury of humpback whales (CA/OR/WA) in all fisheries exceeds 10 percent of the stock’s PBR (Tier 1 analysis).  This single serious injury results in an average mortality and serious injury rate of 0.2 humpback whales per year (when averaged over the last 5 years of data) in this fishery (Tier 2 analysis), or 1.8 percent PBR of 11.3 (2010 SAR), warranting a Category II classification.  NMFS observed this fishery from 2004 through 2009 at coverage levels ranging from 13.3% to 20.9%. 
  • Added humpback whale (CA/OR/WA) and included the notation “¹” following the stock.
  • Reclassified as Category III.  This fishery was classified as Category I based on the level of serious injury and mortality of short-finned pilot whales (CA/OR/WA) in this fishery exceeding the stock’s PBR level.  However, a short-finned pilot whale has not been observed killed or injured in this fishery in the most recent five years of data (2004 – 2008), indicating that the serious injury or mortality of short-finned pilot whales is now zero.  Also from 2004-2008, there were no observed serious injury or mortality of any marine mammal stock for which the average total fishery mortality and serious injury exceeds 10% of the stock’s PBR.   NMFS observed this fishery from 2004 through 2008 at coverage levels ranging from 13.5% to 20.9%. 
  • Deleted short-finned pilot whale (CA/OR/WA).
  • Renamed the “CA thresher shark/swordfish drift gillnet (≥14in. mesh)” fishery.  The OR commercial drift gillnet fishery historically existed as an extension of the CA fishery, targeting swordfish as allowed under the OR Department of Fish and Wildlife’s Developmental Fisheries Program.  For the last few years this fishery has been inactive and OR has not issued permits for such a fishery in state waters.  Also, swordfish were removed from the program in 2009.  OR no longer issues state permits for drift gillnet gear.
  • Estimated number of participants was updated from 85 to 45.
  • Deleted the following species:  Dall’s porpoise (CA/OR/WA), fin whale (CA/OR/WA), gray whale (Eastern North Pacific), humpback whale (Eastern North Pacific), and sperm whale (CA/OR/WA).
  • Deleted the following species because none had been observed taken since the POCTRP regulations were published in 1997:  Baird's beaked whale (CA/OR/WA), bottlenose dolphin (CA/OR/WA offshore), Cuvier's beaked whale (CA/OR/WA), killer whale (Eastern North Pacific offshore); Mesoplodont beaked whale (CA/OR/WA), northern fur seal (San Miguel Island), pygmy sperm whale (CA/OR/WA), Steller sea lion (Eastern U.S.), and striped dolphin (CA/OR/WA). 
  • Changed the stock name of humpback whales to "Eastern North Pacific."
  • Corrections were made to list of species/stocks killed/injured in this fishery to correct errors in previous LOFs:  Killer whale, CA/OR/WA Pacific coast, changed to Eastern North Pacific Offshore stock; long-beaked common dolphin, CA/OR/WA, changed to CA stock.  Northern and Southern stocks of Pacific white-sided dolphins combined to better reflect stock characterization in current SARs.
  • Added a superscript “1” in Table 1 after short-finned pilot whale (CA/OR/WA).
  • Elevated to Category I because new information in the 2003 SARs changed the PBR for short-finned pilot whales (CA/OR/WA) from 5.1 to 1.19 animals/year.  While the mortality and serious injury of short-finned pilot whales in this fishery continued to decrease, the take was still greater than 50% of the updated PBR for this stock.
  • Deleted minke whale (CA/OR/WA).
  • Estimated number of participants decreased from 113 to 85.
  • Reclassified from Category I to Category II because of the implementation the POCTRP in 1997 resulted in a reduction of interactions to below 50% of PBR for the marine mammal stocks with takes driving the classification of the fishery (CA sea lions, Northern right whale dolphins, short-finned pilot whales, sperm whales, fin whales).
  • Renamed "CA/OR thresher shark/swordfish drift gillnet (≥14in. Mesh)" fishery to clarify that it includes drift gillnets of ≥14 in. stretched mesh only.
  • Added fin whales (CA/OR/WA) and gray whales (Eastern North Pacific).
  • Split the Pacific white-sided dolphins (CA/OR/WA) to include Northern Pacific white-sided dolphins (CA/OR/WA) and Southern Pacific white-sided dolphins (CA/OR/WA).
  • Estimated number of participants was decreased from 130 to 113.
  • Added striped dolphin (CA/OR/WA), Northern fur seal (San Miguel Island), and killer whale (CA/OR/WA Pacific coast).
  • Estimated number of participants was decreased from 150 to 130.
  • Added minke whale (CA/OR/WA) because of two mortalities, one each in 1994 and 1996.
  • Deleted harbor seal (CA) and harbor porpoise (OR/WA coastal).


Updated January 15, 2017