Shells from a long distance away?

[kenny396]

Hi, I spend a lot of time at the north end of the Sea of Cortez and the shell collecting is fabulous there...Now I've found shells that seem to have come from other areas, can someone please tell me how far shells can travel, and is it possible for me to have found shells there from a long distance away?

Thanks;  Kenny

[dave r]

Kenny, when you say 'shells from other areas' do you mean in the sea alive or on land or dead? Some species are imported for food and the shells thrown away. If the shells are very old they could be sub-fossil species that occurred there many years ago but no longer do.
Some shells can travel a very long way. If they have larvae that are planktonic they can drift on the curents for many miles. A few species are almost worldwide in distribution because of this dispersion method. As adults they don't tend to travel very far at all, a matter of yards even!
Dave

[kenny396]

 Thank you Dave, but what I was interested in was how far the just the shell of the dead animal might travel in this area in particular, and others as well. There is as much as a 17 to 18 foot tide down at this end of the sea of Cortez, twice a day, and some of these shells are unfamiliar to people who have been in this area for many many years.

Thanks again;  Kenny

[dave r]

It may well be that a climatological or biotopical change has allowed other species to recently move in Kenny, I know this has happened elsewhere. Some warm water species have been expanding their ranges Northwards. This has happened in other animals as well as molluscs. I am aware that the biology of the Sea of Cortez has changed dramatically of late with the top predators being the Humboldt Squid rather than sharks now, maybe this has had a knock-on effect further down the food chain.
Dave

[kenny396]

 Thanks Dave,

Yes, being a avid fisherman who's fished the waters of the north end of the Sea of Cortez since I was a kid, over fifty years, we are catching fish that were at one time only caught much further south. At the same time people are catching fish on the pacific side, that were once only caught in the Sea of Cortez.
One more time, tell me there's no global warming..LOL

Kenny

[dave r]

That is a moot point! lol.
Do you have any shells to trade Kenny? I am very into Olividae and there are somenice ones from there.
Cheers,
Dave