In Scotland on many private salmon fishing beats there is a resident ghillie. The ghillie is usually employed by the estate or beat owner to look after the anglers that fish on the beat. Some beats have more than one ghillie and often the number of ghillies on a salmon fishing beat is determined by the length of the beat as well as the numbers of rods fishing. The ghillie on the beat is there to give anglers fishing advice on where to fish, what methods to use and also point out the likely spots where a salmon may be lying. Ghillies are very experienced and have an intimate knowledge of their beat. They are on the water for the duration of the salmon fishing season and so see the different pools in different conditions. This is what makes them so experienced. 
The services of a beat ghillie is shared amongst all the anglers that are fishing there on that day. The ghillie may give you advice on what flies and lines to use as well showing you the pools and the salmon lies. However, the ghillie is not there to spend the entire day with one angler. He or she has to look after all other the anglers fishing the beat and so will often split their time between the other fishers. For many anglers that have some salmon fishing experience and can read water this is more than adequate. However, if you are a relative novice or never salmon fished in Scotland before you may require the services of an experienced fishing guide.
A dedicated salmon fishing guide provides that one to one service. A fishing guide will usually meet you at your hotel or the fishing beat and then spend the rest of the day with you. Through the course of the day the fishing guide will give you advice on tactics and also help with fly casting if needed. They will be at hand pointing out the best lies and likely spots where a salmon may take whilst you fish down a pool. When you hook a salmon your fishing guide will be there to offer advice during the fight and then eventually net the fish. If you are new to the sport and you are fishing for a few days, it can be worthwhile hiring a fishing guide for the first day. This will ensure that you get a head start when it comes to fishing tactics and technique and stand you in good stead for chasing silver in the days ahead.