[shano]

Марина - несмотря на сходство, не имеет никакого отношения ни к Марии, ни к Марьяне, ни к Марианне

Вики:
Мари́на — женский аналог редкого имени Марин, представляющего собой латинское прилагательное (marīnus — «морской»). Происходит от эпитета Венеры (Venus Marina), греческий аналог — Афродита Пелагея

словарь Петровского:
МАРИНА, -ы, ж.
Производные: Маринка; Маринуша; Мариша; Маша; Марися; Маря (Мара); Маруся; Муся; Ина.
[Женск. к Марин (см.).]

Сайт www.behindthename.com/name/marina
Feminine form of MARINUS

VARIANT: Marijn (Dutch)
DIMINUTIVES: Marinella, Rina (Italian), Ina (German), Rina (Dutch)
MASCULINE FORMS: Marino (Italian), Marino (Spanish), Marijn, Marinus (Dutch), Marinos (Greek), Marin (Romanian), Marin (Croatian), Marin (Macedonian), Marinus (Ancient Roman)
OTHER LANGUAGES: Maren, Marna (Danish), Marine (French), Maren (Norwegian)

мужское имя толкуется так:
From the Roman family name Marinus, which derives either from the name MARIUS or from the Latin word marinus "of the sea".

Viewer
VARIANTS: Marius (Ancient Roman), Marijn (Dutch)
DIMINUTIVE: Rien (Dutch)
FEMININE FORMS: Marina (Ancient Roman), Marijn, Marina (Dutch)
OTHER LANGUAGES: Marijan, Marijo, Marin, Mario, Marjan, Marinko (Croatian), Marian, Marián (Czech), Marius (Danish), Marin, Marius (French), Marius (German), Marinos, Marios (Greek), Marián (Hungarian), Mariano, Marino, Mario (Italian), Marijus (Lithuanian), Marin (Macedonian), Marius (Norwegian), Marian, Mariusz (Polish), Mariano, Mário, Marinho (Portuguese), Marian, Marin, Marius (Romanian), Marián (Slovak), Marijan, Marjan (Slovene), Mariano, Marino, Mario (Spanish), Meirion, Merrion (Welsh)

MARIUS, в свою очередь
Roman family name which was derived either from MARS, the name of the Roman god of War, or else from the Latin root mas, maris meaning "male". Gaius Marius was a famous Roman consul of the 2nd century BC. Since the start of the Christian era, it has occasionally been used as a masculine form of MARIA.

VARIANTS: Marianus, Marinus (Ancient Roman)
FEMININE FORMS: Mariana, Marina (Ancient Roman)
OTHER LANGUAGES: Marijan, Marijo, Marin, Mario, Marjan, Marinko (Croatian), Marian, Marián (Czech), Marinos, Marios (Greek), Marián (Hungarian), Mariano, Marino, Mario (Italian), Marijus (Lithuanian), Marin (Macedonian), Marian, Mariusz (Polish), Mariano, Mário, Marinho (Portuguese), Marián (Slovak), Marijan, Marjan (Slovene), Mariano, Marino, Mario (Spanish), Meirion, Merrion (Welsh)

Есть в православных святцах days.pravoslavie.ru/ABC/wm.htm,
В католических тоже есть Марина, и Маринус, и Мариус