Why are sardines packed so tightly in the can?

Sardine in popular culture
Sardines are typically tightly packed in a small, flat can, the lid of which is scored for easy opening either with a pull tab, or a church key attached to the side of the can. Thus, it has the virtues of being an easily portable self-contained source of food, and often such things as sewing kits or survival kits are packed in a similar container [3]. The close packing of sardines in the can has led to their being used metaphorically for any situation where people or objects are crowded together; for instance a bus or subway car.?

http://www.answers.com/topic/sardine

What would you separate them with, to make them further apart? I don't think they are compressed in any way. They are laid alternately in opposite directions, and their natural shape defines how closely they are packed.

https://en.wikipedia.org/wiki/Image:2006_sardines_can_open.jpg

https://en.wikipedia.org/wiki/Sardines

[Two links added -- Zb]

All canned fish are tightly packed. You have to flake tuna apart with a fork, it's so crammed into the can. Here's a picture of salmon in the can.

http://tonkaseafoods.com/index.php?main_page=product_info&products_id=15

I think the sardines seem to be more tightly packed because we see the whole fish instead of chunks of flesh.

Two answers:
1. Because you can use a smaller tin if you pack 'em in tight. Larger tins cost nore, and when you look at the number they do it does add up. (Logical.)
2. (Used as a brainteaser but believed to be based on fact) Because the oil or tomato sause costs more than the sardines, so the more fish you get in, the greater the profit. (No direct evidence to hand - probably could be found if someone's got the time.)