Before you eat anything you catch you will first need to "clean it" this involves removing the innards (guts) of the fish. Some people, Mrs S#2 for example, whilst happy to eat fish cannot manage this part of the task nor can she (they) eat any fish that has its head still on. Thus I have to ruin trout that I catch by not only gutting them but also removing the heads.
The majority of fresh water caught fish are, despite what Hugh Fearnley-Whittingstall may say, inedible. Sea fish on the other hand can almost all be eaten (rare exceptions are not to be found where you live and anyway someone, somewhere will eat them).
There are many fishing boats (no I don't mean trawlers) in your area and they advertise trips at a reasonable rate. Find one that provides tuition (all will show you what to do) and use of equipment (most have a spare rod). So long as you are a reasonable sailor (ie don't chuck-up the minute they cast off) you'll have a happy four or five hours out off the Needles and should, at this time of year, catch Mackerel (best eaten with 24 hours of leaving the water or given to the cat). There will be some dogfish around ~ don't be put off by the name it is sold in Fish n Chip shops as "Rock Salmon". A member of the shark family ~ get the "skipper" to show you how to pick one up or you will find the b@st@rd things will remove the skin from your arm. They have a hide like sand paper and wrap themselves up your arm unless you pick them up one handed by neck and tail simultaneously. Watch out for a "Spur Dog" these look like dog fish and taste the same but have a vicious "spur" on their back that can do some harm. Conger eels abound off the Needles and should you get one they are excellent eating but again the "Skipper" will show you how to handle them. Watch them tho' cos they do bite like f*ck if they get the chance.
Later in the year you should be able to catch Bass down there but they tend to come in October along with the Cod (very few of them around anymore) and Whiting. The Whiting is a close relative of the Cod and tastes/looks very similar when cooked. It is smaller than a Cod but a nice Channel Whiting is a very pleasing meal.
Assuming you want to try Freshwater fishing this divides into either Coarse or Game fishing. Most coarse fish can be caught locally to you in the Avon, Test, Itchen etc and are not edible These include Carp, Tench, Chub. Bream, Pike etc etc etc Good sport but only for pleasure. Game fishing is very expensive. It can cost hundreds to fish for Salmon on the Test and Avon. Trout similarly are expensive £ for lb. Both are strictly for the dedicated angler and frankly need some lessons in the art of catching. To fish in fresh water you will need a Rod Licence from the Environment Agency. These cost about £25 pa and can be obtained via your Post Office. It matters not if the water is "private" the Rod Licence is a pre-requisite for ALL fresh water fishing (I am unsure of the current cost as I get a concessionary rate being disabled). Any Water Bailiff, Environment Agency Officer, Police Officer or any other Angler who holds a licence has a right to ask to see your licence so it must be carried at all time when fishing. Having a licence is not good enough ~ you MUST produce it on demand. Migratory fish (Salmon and Sea Trout) require an additional licence and this costs a lot. A day's fishing for Salmon on the River Test will set you back (depending on location) anything up to £250 and you will only be allowed to keep one fish.
Whoever holds the fishing rights to the water you want to fish in may also demand a fee (Day Ticket or Club Membership) are the usual descriptions. These are obtainable from your local tackle shop who will also be able to tell you which waters are fishing well and which are not. Listen to their advice as they are a mine of information. Most tackle shops have people hanging around in them who would be happy to give you directions/instruction etc. Anglers are like that. Always eager to show off local knowledge but solitary creatures once on the bank with rod in hand.
Fishing in salt water requires no licence and you may keep all you catch. Traditionally on the outward trip in a boat all on board fish for Mackerel and throw their catch into a bucket or dustbin to use as bait once they reach the "mark". If you want Mackerel for eating then tell the "Skipper" before you set out. Strictly speaking it is considered unsporting to keep any fish below a certain size ~ this varies with species ~ but frankly the f*cking things are usually dead before you can get them back in the water anyway so I tend to keep all I catch from the sea.
Sea Fishing from the beach is another art altogether, it requires some strength and specialist rod and reel. These need not be expensive and unless you pick a private beach again it is free. There is an urban myth that the beach between the High and Low water mark belongs (in the UK) to HM The Queen and thus she grants her permission for her subjects to use it free of charge. Probably some basis in truth but I wouldn't test the theory on those posh bits of beach around Sandbanks and such places. If beach fishing always pick a rising tide. You'll catch bugger all whilst the tide ebbs. Best times are the two hours before the high tide and then the "slack" water. A tide time table is available on line from
http://www.pol.ac.uk or for about 50pence from your local tackle dealer. If you are beach fishing avoid clambering over rocks until you are very sure of what you are doing and watch out because time passes very quickly and "one last cast" can make all the difference between walking home or being winched off the rocks by a helicopter.
Trout fishing (usually stocked lakes) for Rainbow Trout can be good fun but again you'll pay more for the time on the bank than you would pay for the fish in Sainsbury. They will be farm bred fish. Some fisheries will allow you to use bait whilst other insist on Fly Fishing only. This is another art form that needs some instruction (usually available on the lake along with equipment hire) but unless you live in North Wales
it is a costly way of catching some supper. My BiL pays up to £50 for a day on a lake in Surrey and gets to keep only two fish. By comparison I pay £10 for a four hour session and can keep three fish. A couple or three 2 and a half pounders makes it worthwhile (they are more than twice the size of a standard Sainsbury Trout).
Obviously all experienced anglers have tales to tell of not only the one that got away but also the ones that didn't. All anglers are born liars.
Anyone can fish ~ tying the line can be learnt from a book or from another angler and is probably the trickiest bit as there is nothing worse than losing a hooked fish because of a badly tied knot ~ the most common problem. I never mind if a crafty fish wraps my line round a root and snaps his way to freedom but I get really angry if I have tied the knot so badly that it slips loose.
Above all remember that there are thousands of books on the subject and it is easy to become an armchair expert ~ the problem is the bloody fish don't read the books! Some times only a hand grenade will ensure success.