Greetings, everyone!
I'm back from my trip, and it was a huge success. We conducted three dives, and we got thirty-five adult horn sharks! All three dives were conducted out of La Jolla Cove, up near the "caves" (to the north/east from the sandy beach entrance). Our third dive was the most productive - we got 12 horn sharks in less than one hour. The only reason we stopped was because we had run out of labeled specimen tubes, and we were barely at half of our starting air pressure! I figured that 35 was a good stopping point - enough for statistical power (with next-generation genetic sequencing). No need to continue harassing the poor devils!
What was strange was that 33 of the 35 sharks were (sexually mature) males. This is very different from what I found at other sites**, which leads me to believe that, at least locally, this population is heavily structured and segregated by age and sex. I had a chat with a fellow from Scripps, and he says that another location up the coast yielded mostly females. Still, we did manage to find three or four egg cases, and at least one of the two females appeared to be gravid, which is a good sign!
So if you're looking to find horn sharks, La Jolla Cove near the caves (~ 15fsw) is the place to be! I will be a hypocrite and ask that you please do not harass them if you find them...they don't enjoy being handled, and I received a couple of small bites through my neoprene!
Thanks for all your help!
Cheers,
SC
(**What I found at other sites agrees with the sex ratios in the published literature - approximately 1.5 males to every female. This site was strange indeed.)
I'm back from my trip, and it was a huge success. We conducted three dives, and we got thirty-five adult horn sharks! All three dives were conducted out of La Jolla Cove, up near the "caves" (to the north/east from the sandy beach entrance). Our third dive was the most productive - we got 12 horn sharks in less than one hour. The only reason we stopped was because we had run out of labeled specimen tubes, and we were barely at half of our starting air pressure! I figured that 35 was a good stopping point - enough for statistical power (with next-generation genetic sequencing). No need to continue harassing the poor devils!
What was strange was that 33 of the 35 sharks were (sexually mature) males. This is very different from what I found at other sites**, which leads me to believe that, at least locally, this population is heavily structured and segregated by age and sex. I had a chat with a fellow from Scripps, and he says that another location up the coast yielded mostly females. Still, we did manage to find three or four egg cases, and at least one of the two females appeared to be gravid, which is a good sign!
So if you're looking to find horn sharks, La Jolla Cove near the caves (~ 15fsw) is the place to be! I will be a hypocrite and ask that you please do not harass them if you find them...they don't enjoy being handled, and I received a couple of small bites through my neoprene!
Thanks for all your help!
Cheers,
SC
(**What I found at other sites agrees with the sex ratios in the published literature - approximately 1.5 males to every female. This site was strange indeed.)
