Salmon Shark Strandings (Lamna ditropis)

Based on elasmo-l postings or emails by Sean Van Sommeran, Richard Rosenblatt, George Montgomery, and Oliver Putz. The Pacific Rim National Park Reserve in Canada (onVancouver Island in British Columbia) has a blog site to report strandings at http://bcsharkreports.blogspot.com/ .

Photograph/
Date
TL (m)
M (kg)
Sex Observations
2 Feb 1999 0.9 m Male

On Feb 2, 1999, 5:00pm, persons strolling the Seabright beach observed and reported a small "chubby" shark that looked like a "great white" thrashing about in the surf. This was reported to the nearby Santa Cruz Museum of Natural History who made a call to the Long Marine Lab UCSC. Peter Macht arrived at the scene with a tank-truck and brought theshark back to the lab. The shark was put into a salt water pool where it eventually expired early the next morning. The first male collected in over a dozen years, the others over a dozen have all been female. Based on 3Feb posting by Sean Van Sommeran, Pelagic Shark Research Foundation,
Total length (stretched) TOT = 95cm; Total length (tail in natural position) TL = 90cm;. Fork length FL = 83cm; Pre-caudal length PCL = 71 cm. Pre-first dorsal length PD1 = 33cm; Preorbital length POB = 7cm; Snout-vent length SVL = 49.5cm; GRTH: Girth G = 55cm; First dorsal height D1H = 9cm; Dorsal caudal margin CDM =:24cm; Preventral caudal margin CPV = 16cm. PL: Pectoral anterior marging P1A = 15.2cm; Pelvic anterior margin: 4.2cm. CLo: Clasper outer length CLO =: 4cm; Clasper inner lengthLength CLI = 9cm. (names and abbreviations were changed to conform to Compagno (1984, 2001, FAO catalogue)

4 Feb 1999 ~1.3  

By coincidence, yesterday we received a juvenile Lamna ditropis that had washed up in the surf at La Jolla Shores. It was somewhat larger than yours (ca 1.3m) and was newly dead. t. This is only the second salmon shark I have seen here. The first was harpooned by a swordfish fisherman back in the days before drift gill nets. Based on 5 Feb 1999 by Richard Rosenblatt, Scripps Institution of Oceanography.

Mid-March 1999     An apperently floundering salmon shark was escorted into deeper water by surfers in mid March. (Beached itself later if I remember corrcctly). Over the last several years more than a dozen salmon sharks have stranded on local beaches, typically in the spring, almost all of them female. Most of these stranded sharks have been approx 1 meter long. Based on elasmo-l posting of 3 Apr 1999 by Sean Van Sommeran, Pelagic Shark Research Foundation.
1 Apr 1999 ~1 m Fem On Thursday afternoon, April 1st 1999, a 1 meter long female salmon shark stranded on a Carmel beach. The animal is now in cold storage at the UCSC Institute of Marine Sciences. Based on elasmo-l posting of 3 Apr 1999 by Sean Van Sommeran.
Ld_images/Ld_M2 Sunset beach 08-02 1.jpg
Aug 2002
0.983   Dave Ebert:: "I don't have the exact day it washed up. It was 983 mm TL, 750 mm PCL, no weight.
dcp_1801.jpg
4 March 2003

~1.2 m?

Male

Stranded near Bodega Bay, CA USA. Photographs by George Montgomery who left message at Bodega Bay Marine Lab. Additional photos: 3, 4, and 5. No size estimate was provided, I guesstimeate TL to be around 1.2 m.

 

Ld_images/DSCN03
26 Aug 2003

1.02 (0.97 FL)

Male

 

Stranded on Ocean Beach, San Francisco. Male who was alive in the surf the previous afternoon and picked up by park rangers. Later picked up by Corrine R. Davis, D.V.M, Department of Comparative Medicine, Stanford University School of Medicine. Email: crdavis@stanford.edu.

 

Ld_images/LdStrandingBody.jpg
Summer 2005

 

 

Stranding from off from the Oregon coast. Idendified as salmon shark (Lamna ditropis) based on overall form (Gestalt) by Dave Ebert.
Photo of head

 

Ld_images/LdIMGP0559.jpg
03 Jul 2007

~0.77 PCL

F

The animal was washed up on July 3 at Limantour Beach on Point Reyes CA (about 500 m west of Coast Camp). Observed by Oliver Putz.  A wound at the base of the dorsal fin suggests that the animal may have been tagged..  
Photo of head; photo of head; photo of caudal fin.

Ld_images/IMG_2917.jpg
23 Aug 2007

est.
~ 1 m

F

Found on Salishan Beach, Lincoln City, Oregon on August 23, 2007.
Annie Savaria-Watson, Portland, OR

Ld_images/BH Salmon Shark 2008.jpg
04 Aug 2008

est. ~ 0.9 m

?

The juvenile Salmon Sharks are back for their 3rd year of August strandings in the Pacific Rim National Park Reserve area (that we have documented). Sadly, the ~3 foot little guys seem to get disoriented or sick and push ashore until they die. Many kind people have tried to put them back in the water but they often wash up dead the next day and not far away. Keep trying though. Tanya.Dowdall@pc.gc.ca, Park WardenPacific Rim National Park Reserve P.O. Box 280 Ucluelet, BC V0R 3A0 250-726-7165 ext 230. blog site to report strandings at http://bcsharkreports.blogspot.com/ .


Aug 2010

 

 

The Pelagic Shark Research Foundation Stranding and Collecting Unit has reported six verified shark strandings along the Monterey Bay coast in the past 10 days. Between 20 and 30 juvenile salmon sharks strand themselves on the beach each year along the California coast, according to Sean Van Sommeran of the Pelagic Shark Research Foundation. Although the strandings have been recorded by local biologists for more than 20 years, the cause remains a mystery. Researchers plan to dissect two of salmon sharks collected this past week, but officials believe the cause could be related to a nasal infection that affects the sharks' brain function. Fifteen stranded salmon sharks were examined in a 2000-03 study by Dr. Corrine R. Davis of Stanford working with UC Santa Cruz campus veterinarian Dave Casper and Van Sommeran. Of the 15 brains examined, 12 had bacterial meningitis and encephalitis, according to an abstract written up by the researchers. A carnobacterium, or nasal bacteria, was found. Davis wrote "This is a 'fish' bug, but we do not know where the sharks get the infection or if the organism is part of the normal gut flora of the shark. We are working on these latter questions." At some point, the sharks become disoriented, show symptoms similar to domoic acid poisoning and end up on the beach.

Photograph/
Date
TL (m)
M (kg)
Sex Observations

Created February 2002, revised August 2010. Back to previous page
Please send comments or corrections to henry@elasmollet.org