Divers: What do you see?

[shellim123]

I thought the survey was a little odd.

I filled it out; but it seems like you're not collecting a lot of data in a concise manner. (no offense)

I would say that I see at least 1 shark (most commonly a nurse shark) on every 1 out of 5 dives. I've only seen 1 hammerhead in the water, and only a few bulls.

Does that include Michelle's PET shark?

 

[Walter]

I see more sharks now than when I started diving. As I was filling our your survey, I noticed I had much higher totals in 2000 - 07 than for 1990 - 99 and they were higher than for 1980 - 89. I also have seen lots of sharks in areas when I don't necessarily have 20 total dives - Grenada for example I saw about 13 - 15 (log not with me to confirm numbers), but only made 14 dives. Offshore North Carolina, I only made 2 dives (bad weather cut the first day short and cancelled the rest of the trip), yet I saw 18 sharks.

A survey of this type done from memory is pretty much useless. I have an exceptionally good memory, but it is not perfect. If I had gone from memory, my survey infor would not be close to accurate, especially for dives that took place quite some time ago. How would I remember which site I saw more than one shark?

 

[Karibelle]

Walter, I totally understand how long it takes to go through dive logs. Thats why it is designed to be from memory.

If you have logged your dives with your sightings, you are a special case- Fantastic. People like you allow me to get an estimate of memory error. It would be great if everyone that had a log book with sightings recorded, filled out the survey from memory and then filled it out from their log books (or sent me copies of logbooks in most cases and I do all the dirty work)- of course, I pay all expenses for copies and shipping.

Sharkgirl, Have you tried checking the REEF database? There is a lot of good info in there about shark sightings... www.reef.org, go under "reef data" and select "the REEF database" and then select "DATA" from the top line... select a geographic area, select a fish family, and voila!

kari

 

[HowardE]

Does that include Michelle's PET shark?

yeah... but the survey didn't really ask it in a total count of each species.

 

[Sharkgirl]

Although the survey may seem 'odd' I assure you it has been designed to maximize efficiency- minimize the number of questions and maximize the output of data.
I am interested in:
1) percent of sites where you see sharks. I get this from "number of sites visited" and "number of sites where you saw sharks (e.g. in Jamaica it is 0% vs. North Bahamas ~50% ).
2) species richness (how many species you saw) (e.g. in Florida Keys ~2 species vs. North Bahamas ~6 species).
3) shark schools: of the sites where you saw sharks, how many did you see more than one shark- then you list the number of each species (e.g. Cozumel: 1 Nurse at 10 sites vs. Belize ~40 reef sharks, 2 bulls, and 20 nurse at 2 sites)

 

[Sharkgirl]

Walter, I am sorry if you think my survey is useless... but I assure you I have measures to account for memory loss and to standardize the data. For example, some people are filling out the survey from memory and then filling it out using a log book (in most cases they send copies of logbooks to me so I can do the dirty work). That way I can get an estimate of error.

 

[Sharkgirl]

Howarde, Yes, the survey does ask for the maximum number of each species seen on a dive. You answered that portion of the survey correctly- thank you.

 

[Sharkgirl]

Karibelle, Thank you for the REEF link. I have been working with that database for 2 years now. It is a super database for shark/ray sightings!
For this study, I will use it to triangulate the data with the surveys from memory (my survey) and scientific reef fish assemblage data for the Caribbean. The point of my survey, in addition to the REEF data, is to get a more global picture of shark populations and a longer time trend (more than 13 years).