Where to find horn sharks in Southern California?

[scanfield]

Greetings, everyone!

Just giving an update - had three days of diving at Malaga Cove and Veteran's Park at Redondo Beach. Malaga Cove was a bust - three dives yielded no horn sharks. We were able to sample from fifty-one sharks, however, at VP/RB! Fifty of those were 25 cm or less in length - just babies!

We lost our clippers on the first day, so we had to switch to dissecting scissors. It took some time to figure out a good sampling/cutting procedure with those. We didn't want to hurt the little ones too badly! Some cuts were a little rough, I regret to say, but none of the wounds should prove detrimental. All of the little ones were spotted in 8 to 15 feet of water during mid-day. I get the impression that they must venture to slightly deeper water at night for feeding, and retreat to the shallows during the day, where large predators are mostly absent (according to my own observations). There were several lingering around a small field of sand-dollars near the pier to the north of the beach. We found about five or six right there. We also found a 45 cm long female hiding in the rocks of the jetty to the south - a pleasant surprise!

We went to an unfamiliar site for our last dive and found two large horn sharks. Found out later that it was actually Flat Rock! A missed opportunity, but I'm happy with our results overall. An all-juvenile set of samples could be problematic for population genetic analysis, but it could also prove interesting! We'll see.

Next stop is the Laguna area in early to mid August.

Thanks again for all the tips and advice! My new clippers will arrive tomorrow, so no more messing around with clumsy dissecting scissors! I'm sure the horn sharks will be grateful.

- SC

 

[scanfield]

Hi Everyone!

One more update.

In total I've been able to sample tissues from 196 horn sharks this summer:

- 72 from Santa Catalina Island
- 42 from Malibu
- 53 from Redondo/Palos Verdes
- 29 from Laguna

Laguna was a challenge, because conditions were a tiny bit rough. My dive buddy lost some of his equipment and got hurt (a minor injury, he was able to sleep it off). All in all, we got 29 from Laguna, which isn't too bad (though the accepted "minimum" for a sampling site/location is generally 30 for population genetic studies; I think we can still work with 29). The best site was Crescent Bay, on the west side, and the horn sharks got more plentiful as we headed away from shore, just east of Seal Rock.

We managed to find two at Shaw's Cove (one was HUGE!), four at Heisler Park, and two at Divers' Cove - not for lack of trying!

I will say that Shaw's Cove was my favorite dive site by far, even though it wasn't very fruitful overall in terms of horn sharks. I decided to only dive there once, after we assessed the site, but if I had my choice of sites for a fun-dive, Shaw's would be my first choice, followed (somewhat distantly) by Crescent Bay.

Thanks again for all your advice! I might be back out this Spring to sample from the La Jolla area, and I'll definitely pick your brains if that is the case! I really appreciate all your help.

Cheers,

SC

 

[scanfield]

Greetings!

Still ever on the hunt for more tissue samples, I'll be in the La Jolla area in late March looking for Heterodontus (horn sharks)! I know there have been some recommendations for this area earlier in the thread, but if you have any other advice/tips for potential locations, I'd be very grateful!

Many thanks,
SC

 

[scanfield]

Hello again,

It looks like I've been able to narrow my sampling locations down to three sites: La Jolla Cove, La Jolla Shores, and Fletcher Cove Beach Park. There are (reportedly) horn sharks to be found at these sites, and Google Earth reveals a considerably large patch of kelp at La Jolla Cove...which has proven promising in the past!

Does anyone have specific advice for diving these sites re: safety, entry, etc.? Does anyone have any experiences they'd be willing to share?

Thanks again for your time!

Cheers,
SC

 

[Buoy_A]

Hello again,

It looks like I've been able to narrow my sampling locations down to three sites: La Jolla Cove, La Jolla Shores, and Fletcher Cove Beach Park. There are (reportedly) horn sharks to be found at these sites, and Google Earth reveals a considerably large patch of kelp at La Jolla Cove...which has proven promising in the past!

Does anyone have specific advice for diving these sites re: safety, entry, etc.? Does anyone have any experiences they'd be willing to share?

Thanks again for your time!

Cheers,
SC

At La Jolla Cove, I seem to recall seeing more horn sharks near the shallows (it's been a long time since I dove the shallows at the Cove) in less than 10 ft of water than in the kelp. The shallows that are near the caves; which is the south side of the Cove. Very rocky with lots of sea grass growing on the rocks. I'd definitely avoid those shallows at night though; gets very surgy and you sometimes get pushed around rocks.

That kelp at the Cove is typically at between 25-45 ft. I did see one rather large horn shark in the kelp two weeks ago though.

Can't believe you found so many horn sharks in Redondo Beach. I don't think I've seen that many in all my life.

Good luck with your research!

 

[Sheri SGR]

I see them regularly at Malibu Road. Not so much at Point Dume and occasionally at Leo Carrillo in the shallows ear surfers rock.

 

[nathm055]

Hello again,

It looks like I've been able to narrow my sampling locations down to three sites: La Jolla Cove, La Jolla Shores, and Fletcher Cove Beach Park. There are (reportedly) horn sharks to be found at these sites, and Google Earth reveals a considerably large patch of kelp at La Jolla Cove...which has proven promising in the past!

Does anyone have specific advice for diving these sites re: safety, entry, etc.? Does anyone have any experiences they'd be willing to share?

Thanks again for your time!

Cheers,
SC

All the info you'll need here:

Divebums - A San Diego Dive Website

Beach Dive Site: Shores Main Wall, La Jolla, San Diego, CA

As for Horn Sharks, I've never seen them out of La Jolla Cove (been there ~10 times, but usually we head W into kelp forest). It is a marine reserve so I'm not sure what kind of "tissue samples" you're collecting but be aware that if you come out of the water with sharks the lifeguards will nail you.

I have always seen them off of LJ Shores (edit: this is also a marine reserve), above the wall at Vallecitos Point (see top link), however not in the kind of abundance you seem to have found at other sites.

La Jolla Shores is very easy; huge park, showers etc for setup and cleaning off. Just make sure to get there very early (at least <8am) to find parking and get a good spot.

Good luck!

 

[scanfield]

All the info you'll need here:

Divebums - A San Diego Dive Website

Beach Dive Site: Shores Main Wall, La Jolla, San Diego, CA

As for Horn Sharks, I've never seen them out of La Jolla Cove (been there ~10 times, but usually we head W into kelp forest). It is a marine reserve so I'm not sure what kind of "tissue samples" you're collecting but be aware that if you come out of the water with sharks the lifeguards will nail you.

I have always seen them off of LJ Shores (edit: this is also a marine reserve), above the wall at Vallecitos Point (see top link), however not in the kind of abundance you seem to have found at other sites.

La Jolla Shores is very easy; huge park, showers etc for setup and cleaning off. Just make sure to get there very early (at least <8am) to find parking and get a good spot.

Good luck!

I do have a collection permit from CDFW, and the marine reserves associated with these sites are explicitly mentioned (though I'll need to double check with their offices to make sure these sites are mentioned, and if not, I can certainly get an amendment). I don't perform lethal sampling, nor do I at any point remove the animals from the water. I measure them and take a small piece of tissue from the posterior margin of the first dorsal fin, drop it in a collection tube, and let the sharks be on their way. That's the beauty of genetics: you don't need much!

Horn sharks are funny in that they're pretty good at hiding in plain sight, but also tend to find all the nooks and crannies to hide in during the day to avoid sunlight. I've surprised more than a few people with how many I've been able to find at various sites. Once you get a good search-image and know which habitat they're likely to prefer, you start seeing them all the time. The more structurally complex the bottom habitat is, the less likely you are to see them at a glance, but the more likely they are to actually be there, hidden.

I have been using ecodivecenter.com for preliminary research of dive sites (it's how I've found most of my sites in the past), and it's awesome! But I'm curious about the bottom habitat at La Jolla Shores...would you be willing to describe it a little bit? I know you find the horn sharks most commonly in shallow areas (< 40 fsw...which is perfect, because that's the deepest I'm currently allowed to dive for scientific research). Is this usually sandy-bottom? How big are the horn sharks that you usually see, and are they associated with any specific bottom-features?

I really appreciate your help! Thanks so much.

Cheers,
SC

EDIT: Ah, I see that the Dive Bums website answers some of my questions.

 

[nathm055]

I do have a collection permit from CDFW, and the marine reserves associated with these sites are explicitly mentioned (though I'll need to double check with their offices to make sure these sites are mentioned, and if not, I can certainly get an amendment). I don't perform lethal sampling, nor do I at any point remove the animals from the water. I measure them and take a small piece of tissue from the posterior margin of the first dorsal fin, drop it in a collection tube, and let the sharks be on their way. That's the beauty of genetics: you don't need much!

Horn sharks are funny in that they're pretty good at hiding in plain sight, but also tend to find all the nooks and crannies to hide in during the day to avoid sunlight. I've surprised more than a few people with how many I've been able to find at various sites. Once you get a good search-image and know which habitat they're likely to prefer, you start seeing them all the time. The more structurally complex the bottom habitat is, the less likely you are to see them at a glance, but the more likely they are to actually be there, hidden.

I have been using ecodivecenter.com for preliminary research of dive sites (it's how I've found most of my sites in the past), and it's awesome! But I'm curious about the bottom habitat at La Jolla Shores...would you be willing to describe it a little bit? I know you find the horn sharks most commonly in shallow areas (< 40 fsw...which is perfect, because that's the deepest I'm currently allowed to dive for scientific research). Is this usually sandy-bottom? How big are the horn sharks that you usually see, and are they associated with any specific bottom-features?

I really appreciate your help! Thanks so much.

Cheers,
SC

EDIT: Ah, I see that the Dive Bums website answers some of my questions.

Sorry is this is too late...but the sharks usually are small (<2'), and hang out above and below the wall. I don't specifically remember the depth which I saw them but I'm guessing more between 40-60' than the in the sandy shallows. The environs leading up to the wall are just sand, drifting seaweed, and sand dollar beds; no kelp, not much grass, just sand, since it's right off the beach. Hope that helps, and good luck!

 

[scanfield]

Sorry is this is too late...but the sharks usually are small (<2'), and hang out above and below the wall. I don't specifically remember the depth which I saw them but I'm guessing more between 40-60' than the in the sandy shallows. The environs leading up to the wall are just sand, drifting seaweed, and sand dollar beds; no kelp, not much grass, just sand, since it's right off the beach. Hope that helps, and good luck!

Thanks very much! That's extremely helpful.

I'll be in the area in about two weeks - getting excited! I miss California diving.