No – you do not need to take black pepper with turmeric.
There is a lot of confusion on this subject. Black pepper extract (also known as bioperine), prevents the breakdown of curcumin in the liver and digestive system, which increases its time in the body. Although curcumin is an extract of turmeric, there is no evidence to suggest that you need to take black pepper with turmeric to get these effects. Generally, your average curcumin supplement will contain 100mg+ of concentrated curcumin, whereas turmeric root contains 2-3% of curcumin, along with many other nutrients. Although similar, they are significantly different supplements, and should be treated as such. It is often a good idea to take black pepper extract with a curcumin supplement though, and the research does support this. You can read more about black pepper and turmeric/ curcumin here.
Although there is no research specifically looking at black pepper extract and turmeric retention/ absorption, it stands to reason that it would help improve the absorption of the curcumin found in turmeric. This may well be true. However, the benefits would be extremely small, so although you do not need to take them together, it certainly would do you no harm.
More importantly, turmeric supplements should be taken with food. Like all supplements, their absorption and retention in the body is improved by other foods and digestive enzymes. If this food happens to contain pepper, then no harm done.