Estimates of the “Known” and “Unknown” Marine Biota of the Gulf of Maine 1

It is safe to assume that scientists do not know all the species that live in the Gulf of Maine. But can we estimate how many species might be left to discover? Or what percentage we know? Here an attempt has been made to do just that. Unsurprisingly, we project that far more tiny species are left to be discovered than large species.

I. Unicellular photosynthetic organisms, macrophytes and metazoa identified in the Bay of Fundy taxonomic list 2
Number of Species
  Known Unknown
Phytoplankton 310 ? *
Macrophytes 271 -
Invertebrates 1414 ???
Chordates 37 ?
Fishes 120 ** -
Birds 177 0
Mammals 24 0
TOTAL 2353 ???
II. Microbial community 3 ***
  % Known (estimated)
Viruses << 1%
Bacteria < 1%
Heterotrophic protists 5 – 10% ****
Phototrophic protists 10 – 20% ****

1 This list does not include the continental slope or the western New England Seamounts, which will be covered by a separate table.
2 Source: Atlantic Reference Center, St. Andrews, NB, Canada.
Bay of Fundy list. The list of identified taxa is being added to as the geographic range of the list is expanded to include the rest of the Gulf of Maine under the “North Atlantic Registry of Marine Species”, which is in progress; as further exploration and taxonomic work is undertaken; and as new immigrants become established.
3 Source: M. Sieracki and C. O’Kelley, Bigelow Laboratory for
Ocean Sciences, West Boothbay Harbor, ME. Screening methodologies and taxonomic questions in this evolving field preclude a simple statement about number of known taxa..
* A single interrogation mark “?” indicates that there are possibly/probably some unknowns, triple marks indicate that the number is likely large (especially small benthic infauna). Species lists for macrophytes and fishes are assumed to be complete (“-”), but are open to new arrivals; lists for birds and mammals are complete but also subject to new arrivals.
** Note that the recent revision of Bigelow and Schroeder’s Fishes of the Gulf of Maine edited by B. Collette and G. Klein-McPhee lists 252 species for the Gulf of Maine, including a large number of seasonal migrants from the south or north and a small number of reported “strays”. Eighty-seven are listed as resident species.
*** “Microbes” include all single-celled organisms (Prokarya, Eukarya and viruses). The estimates provided here include all phytoplankton from Part I (above) as phototrophic protists and some of the invertebrates (radiolarians, foraminifera and tintinnids) from Part I as heterotrophic protists.
**** The “unknown” protists are primarily the very small “picoeukaryotes.”