Fishery Status of Thresher Sharks:

So with all the great reports about catching Threshers, it occurred to me, how are they doing?  The answer, according to NOAA, is pretty good:

Sustainability Status:

Fishing Mortality – Based on analyses of productivity, CPUE, and catch data, fishing mortality is estimated to be below the rate that would produce maximum sustainable yield; thus, overfishing is not occurring (PFMC 2010).

Biomass – Biomass is estimated to be above that required for maximum sustainable yield and the stock is reportedly not overfished (PFMC 2010).

Bycatch – Thresher sharks are taken incidentally in the swordfish DGN fishery. Historically, there have been concerns about the level of bycatch of marine mammals and turtles in this fishery; however, after changes in fishing practices to minimize interactions with protected species, NMFS believes there is currently only a remote likelihood of incidental mortality or serious injury to marine mammals based upon the most recent information.

Life History and Habitat (see PFMC 2003 and Smith et al. 2008)

Geographic range – The geographic range of common thresher sharks in the Northeast
Pacific is from Goose Bay, British Columbia, Canada to the Baja Peninsula, Mexico and out to about 200 miles from the coast.

Habitat – The SWFSC annual survey and electronic tagging studies show habitat separation between juveniles and adults. Juveniles tend to remain over the continental shelf in shallow water while adults are most common in deeper water but rarely range beyond 200 miles from the coast. Both juveniles and adults are often associated with highly productive or “green” water in regions of upwelling or intense mixing.

Life span – Estimated range from 19 to 50 years; additional research is necessary.

Growth rate – Approximately 30 cm per year over the first 5 years. Maximum size – 550 cm total length for U.S. West Coast.

Maturity – Approximately 5 years old and around 166 cm fork length for both sexes. Reproduction – Aplacental ovovivaparity and oophagous: Eggs are deposited into one of two uterine horns and developing embryos are nourished by feeding on other eggs. The typical litter size is 2-4 pups and gestation is thought to be around 9 months.

Pupping season – Pupping is thought to occur in the spring off southern California. Mating is thought to occur in the summer.

Nursery ground – The nursery grounds for pups is over the continental shelf in waters 90 m or less, primarily from Point Conception, California to San Vizcaino Bay, Baja California, Mexico.

Stock Structure – Genetics, catch, and tagging data suggest a single homogenous west coast population of common thresher sharks.
 
Migration – Seasonal migrations are thought to be linked to temperature with north-south movements between Oregon/ Washington and Southern California/ Baja Peninsula, Mexico.

Thanks for the info Dave.

There are times when thresher sharks crowd an area and stay in the vicinity for weeks. During that time, they are usually easy to hook (not always easy to land). And the urge to catch more is strong...because they fight so well. But I think it would be wise to exercise caution and C&R if possible. Not passing judgement...just saying that I will never keep a thresher again. Unless it's like 15ft long, and I'm on a boat...and I'm really hungry.   

Good news.
I'll be happy with one in the 80lb range

But I think it would be wise to exercise caution and C&R if possible. Not passing judgement...just saying that I will never keep a thresher again. Unless it's like 15ft long, and I'm on a boat...and I'm really hungry.

I have to agree after seeing what you went through with your thresher shark during last year's Islander trip.