People sometimes use the word dolphin and porpoise interchangeably. However this is a mistake, as dolphins and porpoises are in fact different animals.
Dolphins make noise using a special part of their anatomy called nasal air sacs.
There are several organizations which are devoted to protect dolphins, however they have no further influence than exposing the atrocities made by humans and organizations against dolphins.
A group of dolphins is called a pod. A pod usually is formed of around 12 dolphins and it is the usual social group of dolphins.
A dolphin pod is a group of dolphins.
To rescue dolphins, the first and most important issue is to reduce the risk which dolphins face daily caused by humans are.