The simple answer is no, search engine submission isn’t necessary. The majority of search engines nowadays (most notably Google) crawl and index pages by following links. Using that logic, a single inbound link from any already-indexed page will identify your page to the search engine. Subsequently, if that page links to other pages within your site, they will also be indexed… and so on.
For this reason, getting other sites to link to your site is very important. In fact, acquiring these so called “back-links” may be the most important part of SEO for your recruitment website. In theory though, a website owner shouldn’t have to ’scout’ or ‘hunt’ for links. If you have interesting content that is useful, and/or important, there is a natural tendency among web users to link to such information. This is the basis for the Google PageRank algorithm.
While not absolutely necessary, submitting your site to the search engines can’t hurt. Plus, it only takes about 5 minutes of added work assuming you only submit to Google, Yahoo & Bing… you don’t need to submit your site more than once. It doesn’t help or get your site crawled any quicker or more often. Please note that submitting your site to Google, Yahoo, Bing, and many others doesn’t cost a fee. Many SEO companies say that you need to pay to be indexed. This isn’t the case.