Dear Aspirant, I am glad that you have asked this question. Let me tell you now a days, no body thinks about interpersonal skills, and even people don't want to know about it. Let me tell you that in every field, where one has to encounter with many persons, whether clients, customer , students, colleagues or close ones, the interpersonal skills are very important part of the personality of the person.
Let me first tell you something about interpersonal skills then you will come to know the importance of this skills.
Interpersonal skills are life skills we use every day to communicate and interact with other people whether individual or in a group. People who have worked on developing their interpersonal skills are more successful in their personal and professional life.
People with good interpersonal skills are considered very popular, clam, optimistic, confidant and charismatic among their colleagues and dear and near.
The common interpersonal skills are as:
1. Verbal interpersonal skills: here we communicate with our words or what we say and how we say it.
2. Non verbal skills: here we do not say anything but our body language communicate the meaning
3. Listening skills; how we interpret the meaning of verbal and non verbal communication.
4. Negotiation; working with others to find a mutually agreeable solution

5. Problem solving; working with others to identify, define and find a solution of the problem
6. Decision making; exploring and and analyzing options to make sound decisions.
7. Assertiveness; communicating your ideas, beliefs, opinions, needs and wants freely

Interpersonal skills becomes so natural that we take them as granted and never thought about that seriously. We never think that how we communicate and interact with the people whom we encounter daily. With little efforts any one can improve their interpersonal skills, and after developing one realizes that how comfortable he or she makes to other by his or her behavior.
A fishery scientist has to deal with the colleagues, students and customers, you have to communicate your ideas to everyone. You may be very intelligent but unless you transfer the ideas into someones mind the intelligence has no meaning.
Hope i have explained things nicely..
Good luck..