Here are a few places where you can donate.
National Geographic: https://donate.nationalgeographic.org/Page.aspx?pid=184
Ocean Conservancy: http://www.oceanconservancy.org/support-us/
World Wildlife Fund: https://support.worldwildlife.org/site/SPageServer?pagename=main_monthly_2014&s_src=AWG1507SS912&_ga=1.99638103.853227111.1430603060
One World One Ocean Foundation: http://www.oneworldoneoceanfoundation.org/ways-to-help/donate-now.html
World Nature Organization: http://www.wno.org/donate-now
National Geographic: https://donate.nationalgeographic.org/Page.aspx?pid=184
Ocean Conservancy: http://www.oceanconservancy.org/support-us/
World Wildlife Fund: https://support.worldwildlife.org/site/SPageServer?pagename=main_monthly_2014&s_src=AWG1507SS912&_ga=1.99638103.853227111.1430603060
One World One Ocean Foundation: http://www.oneworldoneoceanfoundation.org/ways-to-help/donate-now.html
World Nature Organization: http://www.wno.org/donate-now