My degree is in zoology and for a while I was a marine biologist afterwards. In the end I switched and did my PhD in palaeontology, and now end up writing about tropical fish for magazines! So go figure...
Anyway, it's very important to understand that almost no marine biology jobs involving diving, playing with dolphins, keeping sharks in aquaria, or really anything like that. The major fields are things like fisheries management, oceanography, and environmental monitoring. So the people who are going to succeed will not be those who know much about marine animals and plants, but biochemists, mathematicians, computer modellers and so on. In fact, there's a good argument for becoming expert in maths, and then picking a field in the sciences where you can apply those math skills. Likewise computing, in terms of modelling and statistics at least.
Jobs are extremely scarce, and if you stay in academia you can expect to work 7 days a week on low wages and with zero job security. Very likely you'll have to move city if not country every three years as each research grant expires. So getting a house or starting a family is very difficult. Simply getting grants is close to impossible (failure rate is something like 98% per grant application) and you'll be up against people who are often smarter, better qualified, and more prepared to work 14 hour days, 7 days a week. Those post-graduate students and junior researchers who succeed in science these days tend to be incredibly focused and dedicated (or, put another way, completely non-social, poor, and with no ambitions outside their work).
I would recommend ANYONE considering marine biology spend time talking with someone working in the field. Get an idea of what the career progression path is (or more accurately, the lack of progression for 90% of the people who start in the field). Think carefully about whether you wouldn't enjoy the science more as an amateur who happens to have a good job as a doctor or banker or lawyer or whatever.
In fact this holds true for most of the "fun" sciences, be it astronomy, palaeontology, archaeology or whatever. Many of the people who enjoy these sciences in the way they want to enjoy them, do it by earning money in a real job, and then spending their weekends or holidays pottering about on exotic field excursions or running their own experiments at home. I've come across vets who also happen to be world experts on fossil sharks, and medical doctors who have built observatories on their houses to search for supernovas and comets.
Cheers, Neale
