**4. Brief characteristics of the algal flora of the western part of Bering Sea and Commander Islands**

In Russian phycological literature the whole water area of the Far Eastern Seas is considered to be divided into 7 large floristic regions: 1) the Sea of Japan, 2) small Kurile Islands region; 3) southern Kurile Islands region; 4) northern Kurile Islands region; 5) the Sea of Okhotsk; 6) Bering Sea; 7) Commander Islands (Perestenko, 1994). We carried out our studies in the last 2 regions and came to a conclusion that the Bering Sea region that according to Perestenko (1994) includes the whole Eastern Kamchatka coasts should be subdivided into 2 subregions practically equal in geographic extension and floristic significance: a) proper Bering Sea area in its geographic borders (from Bering Strait to Ozernoi Gulf) and b) southeastern Kamchatka (from Kamchatskii Gulf to Lopatka Cape). The latter is out of the limits of the present study. Here we discuss marine algal flora of 2 major floristic complexes of the regions located in the upper part of North Pacific, those of Commander Islands and western continental coast of Bering Sea.

From the point of view of phytogeography both floristic complexes judging from the elements forming them may be attributed to boreal (cold-temperate) type (Table 4). The number of arctic-boreal and high-boreal species in the floristic complex of the Commander Islands totals to 41 %, in the floristic complex of western continental part of Bering Sea their number comes to 44 %. If so called wide-boreal elements are taken into account these figures increase correspondingly to 92% and 90 %.

Systematic analysis of the species list revealed that the largest orders in the floristic complex of the Commander Islands are: 1) within the divion Ochrophyta, class Phaeophyceae: Ectocarpales (contains 3 families, 11 genera and 12 species) and Laminariales (5 families, 7 genera and 10 species); 2) within the division Rhodophyta: Ceramiales (4 families, 24 genera and 38 species) and Cryptonemiales (in its traditional interpretation) (5 families, 13 genera and 17 species); 3) withihn the division Сhlorophyta: Ulvales (3 families, 5 genera and 14 species). These orders include above 55 % of the total species number of the flora.

The situation on the western continental coast of Bering Sea is much the same, the largest orders in this floristic complex are: 1) within the division Ochrophyta, class Phaeophyceae: Ectocarpales (contains 3 families, 10 genera and 11 species) and Laminariales (5 families, 8 genera and 12 species); 2) within the division Rhodophyta: Ceramiales (4 families, 18 genera and 31 species) and Cryptonemiales (in its traditional interpretation) (5 families, 12 genera

Marine Macrophytic Algae of the Western Sector of North Pacific (Russia) 201

The Bering Sea marine algal flora presumably (on the assumption of paleonthologically verified data on the other groups of organisms) was formed mostly by low-boreal elements that adapted to fall of temperature in Cainozoic period. At present this flora is being enriched due to the penetration of high-boreal and arctic species (e.g. *Dilsea socialis*, *Rhodomela sibirica*) via cold-water Eastern Kamchatka current. This current goes further to the south and in such a way cold-water species are spread along the south-eastern Kamchatka coasts (up to Lopatka Cape) (Fig. 1). Thus the marine algal flora of Bering Sea has a well-defined migratory character and is under strong influence of the Arctic area. On the other hand Commander Islands are greatly influenced by American continent due to the branch of Alaska current providing penetration of American elements of flora. I suppose this process to be main tendency of the Islands' flora development. As a result of invasion of American elements marine algal flora of the Commander Islands is more rich and diverse as compared to other areas of Bering Sea. For example, elementary analysis of the data from our Tables 1-3 show that there are 57 species of marine macrophytes (9 species of green, 10 – of brown and 38 - of red algae) that are met only on Commander Islands and are not found on the continental coast of Bering Sea. Many of these species were described from the American Pacific coasts (e.g. *Streblonema scabiosum, Acrochaete geniculata, Erythrocladia irregularis*, *Palmaria callophylloides*, *P. hecatensis*, *Laingia aleutica, Nienburgia prolifera, Beringiella labiosa, Tayloriella abyssalis*). Of course, absence of records of some species from the continental part of Bering Sea does not in all cases mean that these algae do not grow there, possibly it is due to less careful studies in this area in contrast to

It should be noted that in spite of the fact that all above-mentioned species were described from the American continent they are not necessarily American in their origin. It is quite possible that marine algal flora of the American continent is just more comprehensively studied and new species are found and described there more often in comparison with the Russian Pacific sector. And it is no wonder, because big and well-equipped groups of phycologists from Canada and USA effectively work in their sector of the Pacific Ocean while in Russia in fact only small isolated groups of enthusiasts try to study marine algae of the western Pacific coasts. In any case the presence of the species on Commander Islands that are not met in other areas of the Russian Pacific but are common with American coast (*Coilodesme californica*, *Pleonosporium vancouverianum*, *Microcladia borealis*, *Tokidaea serrata, Nienburgia prolifera, Laingia aleutica, Beringiella labiosa, Odonthalia floccosa* etc.) brings together their flora with the floras of Aleutian Islands and Alaska. So Commander Islands serve as a

Comparison of the species composition of the macrophytes of the Commander Islands' shelf and that of the south-eastern Kamchatka reveals certain similarity of the floras of these two regions (Jaccard's coefficient of community K**j** = 0.68) and testify to belonging of the Commander Islands flora to Asian type.1 According to my calculations similarity between

1 The geological data are also in favour of hypothesis of Asian origin of marine algal flora of the Commander Islands. In accordance with the theory of continental drift the Pacific islands (together with their underwater foundations) are considered to be the edge chains separated from the continental blocks. During general movement of the Earth crust along the mantle oriented mostly to the west they lagged behind and remained in the east. So their original position was closer to the Asian continent in comparison with the present day (Vegener, 1984). In some sense hypothesis of Asian origin of the Commander Islands marine algal flora is confirmed by data on terrestrial flora of some well studied

peculiar bridge uniting American and Asian algal floras.

Commander Islands.


Table 4. Phytogeographic composition of the macrophytic algae floras of Bering Sea and Commander Islands

and 14 species); and 3) withihn the division Сhlorophyta: Ulvales (3 families, 4 genera and 14 species). These orders include about 54 % of the total species number of the flora.

The largest higher taxon of the Commander Islands' flora is the division Rhodophyta consisting of 13 orders, 25 families, 63 genera and 103 species and exceeding the number of green and brown algae in sum (Phaeophyceae + Chlorophyta) in 1.7 times. Thus, the nucleus of the Islands' flora is represented by red algae. The largest genera within Rhodophyta, consisting of 5 and more species are as follows: *Porphyra* (10 species), *Odonthalia* (7 species), *Palmaria* (5 species) and *Clathromorphum* (5 species). The largest genus among Chlorophyta is *Ulva* (6 species), however Phaeophyceae has no genera with more than 3 species, though it contains the complex of genera *Laminaria+ Saccharina*, but even in this case the number of the species totals to only 4.

The division Rhodophyta is also the largest one in the flora of the western continental coasts of Bering Sea consisting of 14 orders, 25 families, 56 genera and 91 species and exceeding the total number of green and brown algae in 1.5 times. So the nucles of the Bering Sea flora is also formed by red algae though their number is less than that of Commander Islands (91 species versus 103 accordingly). The largest genus within Rhodophyta in the Bering Sea flora is *Porphyra* (8 species), other large genera containing 4 species each are: *Clathromorphum, Acrochaetium, Palmaria* and *Odonthalia*. The largest taxa among division Chlorophyta and class Phaeophyceae are correspondingly the genus *Ulva* (7 species) and the complex of genera *Laminaria+ Saccharina* (5 species).

The figures given above make it possible to outline main characteristics of the floras. Particularly, in accordance with data of systematic analysis in general marine algal flora of both regions can be characterized as variegated in the species composition and allochthonous by origin. It contains big number of monotypic genera and families. I mean those taxa of higher rank that are represented in the studied area by only one taxon of lower rank, i.e. a family represented by one genus and a genus represented by one species. On Commanders there are: 17 genera and 5 families in Phaeophyceae; 12 genera and 7 families in Chlorophyta; 42 genera and 9 families in Rhodophyta; in Bering Sea: 18 genera and 7 families in Phaeophyceae; 7 genera and 5 families in Chlorophyta; 35 genera and 11 families in Rhodophyta. Allochthonous type of the flora is also confirmed by relatively low ratios: species/genus (1.6 for both regions); species/family (3.6 for Commander Islands and 3.4 for Bering Sea) and genus/family (2.3 for Commander Islands and 2.1 for Bering Sea). No endemic species were found. Variegated species composition shows that both floristic complexes are under strong influence of adjacent areas. Main ecologic factors of the existence of contemporary floras of algae-macrophytes in the area are formed by ocean currents.

**Arctic-boreal 17 10 24 16 High boreal 50 31 43 28 Wide boreal 83 51 70 46 Boreal-tropical 8 4 10 6 Cosmopolitan 6 4 6 4** 

Table 4. Phytogeographic composition of the macrophytic algae floras of Bering Sea and

14 species). These orders include about 54 % of the total species number of the flora.

and 14 species); and 3) withihn the division Сhlorophyta: Ulvales (3 families, 4 genera and

The largest higher taxon of the Commander Islands' flora is the division Rhodophyta consisting of 13 orders, 25 families, 63 genera and 103 species and exceeding the number of green and brown algae in sum (Phaeophyceae + Chlorophyta) in 1.7 times. Thus, the nucleus of the Islands' flora is represented by red algae. The largest genera within Rhodophyta, consisting of 5 and more species are as follows: *Porphyra* (10 species), *Odonthalia* (7 species), *Palmaria* (5 species) and *Clathromorphum* (5 species). The largest genus among Chlorophyta is *Ulva* (6 species), however Phaeophyceae has no genera with more than 3 species, though it contains the complex of genera *Laminaria+ Saccharina*, but even in

The division Rhodophyta is also the largest one in the flora of the western continental coasts of Bering Sea consisting of 14 orders, 25 families, 56 genera and 91 species and exceeding the total number of green and brown algae in 1.5 times. So the nucles of the Bering Sea flora is also formed by red algae though their number is less than that of Commander Islands (91 species versus 103 accordingly). The largest genus within Rhodophyta in the Bering Sea flora is *Porphyra* (8 species), other large genera containing 4 species each are: *Clathromorphum, Acrochaetium, Palmaria* and *Odonthalia*. The largest taxa among division Chlorophyta and class Phaeophyceae are correspondingly the genus *Ulva* (7 species) and the

The figures given above make it possible to outline main characteristics of the floras. Particularly, in accordance with data of systematic analysis in general marine algal flora of both regions can be characterized as variegated in the species composition and allochthonous by origin. It contains big number of monotypic genera and families. I mean those taxa of higher rank that are represented in the studied area by only one taxon of lower rank, i.e. a family represented by one genus and a genus represented by one species. On Commanders there are: 17 genera and 5 families in Phaeophyceae; 12 genera and 7 families in Chlorophyta; 42 genera and 9 families in Rhodophyta; in Bering Sea: 18 genera and 7 families in Phaeophyceae; 7 genera and 5 families in Chlorophyta; 35 genera and 11 families in Rhodophyta. Allochthonous type of the flora is also confirmed by relatively low ratios: species/genus (1.6 for both regions); species/family (3.6 for Commander Islands and 3.4 for Bering Sea) and genus/family (2.3 for Commander Islands and 2.1 for Bering Sea). No endemic species were found. Variegated species composition shows that both floristic complexes are under strong influence of adjacent areas. Main ecologic factors of the existence of contemporary floras of algae-macrophytes in the area are formed by ocean

**Total 164 153**

**Species number**

this case the number of the species totals to only 4.

complex of genera *Laminaria+ Saccharina* (5 species).

**Commander Islands Continental part of Bering Sea** 

**number**

**%** 

**% Species** 

**Phytogeographic group** 

Commander Islands

currents.

The Bering Sea marine algal flora presumably (on the assumption of paleonthologically verified data on the other groups of organisms) was formed mostly by low-boreal elements that adapted to fall of temperature in Cainozoic period. At present this flora is being enriched due to the penetration of high-boreal and arctic species (e.g. *Dilsea socialis*, *Rhodomela sibirica*) via cold-water Eastern Kamchatka current. This current goes further to the south and in such a way cold-water species are spread along the south-eastern Kamchatka coasts (up to Lopatka Cape) (Fig. 1). Thus the marine algal flora of Bering Sea has a well-defined migratory character and is under strong influence of the Arctic area.

On the other hand Commander Islands are greatly influenced by American continent due to the branch of Alaska current providing penetration of American elements of flora. I suppose this process to be main tendency of the Islands' flora development. As a result of invasion of American elements marine algal flora of the Commander Islands is more rich and diverse as compared to other areas of Bering Sea. For example, elementary analysis of the data from our Tables 1-3 show that there are 57 species of marine macrophytes (9 species of green, 10 – of brown and 38 - of red algae) that are met only on Commander Islands and are not found on the continental coast of Bering Sea. Many of these species were described from the American Pacific coasts (e.g. *Streblonema scabiosum, Acrochaete geniculata, Erythrocladia irregularis*, *Palmaria callophylloides*, *P. hecatensis*, *Laingia aleutica, Nienburgia prolifera, Beringiella labiosa, Tayloriella abyssalis*). Of course, absence of records of some species from the continental part of Bering Sea does not in all cases mean that these algae do not grow there, possibly it is due to less careful studies in this area in contrast to Commander Islands.

It should be noted that in spite of the fact that all above-mentioned species were described from the American continent they are not necessarily American in their origin. It is quite possible that marine algal flora of the American continent is just more comprehensively studied and new species are found and described there more often in comparison with the Russian Pacific sector. And it is no wonder, because big and well-equipped groups of phycologists from Canada and USA effectively work in their sector of the Pacific Ocean while in Russia in fact only small isolated groups of enthusiasts try to study marine algae of the western Pacific coasts. In any case the presence of the species on Commander Islands that are not met in other areas of the Russian Pacific but are common with American coast (*Coilodesme californica*, *Pleonosporium vancouverianum*, *Microcladia borealis*, *Tokidaea serrata, Nienburgia prolifera, Laingia aleutica, Beringiella labiosa, Odonthalia floccosa* etc.) brings together their flora with the floras of Aleutian Islands and Alaska. So Commander Islands serve as a peculiar bridge uniting American and Asian algal floras.

Comparison of the species composition of the macrophytes of the Commander Islands' shelf and that of the south-eastern Kamchatka reveals certain similarity of the floras of these two regions (Jaccard's coefficient of community K**j** = 0.68) and testify to belonging of the Commander Islands flora to Asian type.1 According to my calculations similarity between

<sup>1</sup> The geological data are also in favour of hypothesis of Asian origin of marine algal flora of the Commander Islands. In accordance with the theory of continental drift the Pacific islands (together with their underwater foundations) are considered to be the edge chains separated from the continental blocks. During general movement of the Earth crust along the mantle oriented mostly to the west they lagged behind and remained in the east. So their original position was closer to the Asian continent in comparison with the present day (Vegener, 1984). In some sense hypothesis of Asian origin of the Commander Islands marine algal flora is confirmed by data on terrestrial flora of some well studied

Marine Macrophytic Algae of the Western Sector of North Pacific (Russia) 203

of indigenous small people of the North – Aleutians with their traditional mode of life and culture that also need protection. Based on these grounds the Commander Reserve was included in the worldwide net of the biosphere reservations in the frames of the

Organization of the state reserve helps to take under protection all marine organisms inhabiting the Islands, including marine macrophytic algae. And this fact inspires optimism because the majority of rare species included in the Red Data Books of Kamchatka and Russia grow on Commander Islands. In most cases the Islands are the only area of their inhabitance within the Russian coasts (Selivanova, 2007). Conservation of these species in the nature has not only scientific importance but is an integral part of conservation of biodiversity of the coastal zone in its broad sense (i.e. not only of the species diversity but

It is expedient to note that all species included in the Red Data Book of Kamchatka are rare because of natural reasons, their number is not reduced by human activity and their conservation needs rather non-interference in natural habitats than any active measures of protection. However it is necessary to exclude anthropogenic pollution of the coastal area and poaching in the Reserve's water area. Of course, rare algae themselves cannot be the objects of harvesting but irrational catch of other hydrobionts may cause nonreversible changes in marine ecosystems and as a result – extermination of rare species of algae. In fact there are groups of algae growing on Commander Islands that should be attributed to the category of so called vulnerable species and these are commercial laminarian species (*Laminaria*, *Saccharina*). At present they are abundant on the Islands and there are no real threats for decrease in their diversity. In my opinion remoteness of the Islands, small number of their human population and relatively low demand for the plant marine products will prevent local community from poach harvest of seaweeds as it happened in the vicinity of Petropavlovsk-Kamchatskii. However there is a risk of their overharvest in case of large-scale uncontrolled commercial catch. I think that this perspective should be treated as a possible threat for the biodiversity conservation on the shelf of the Commander

Reserve "Karaginskii Island" is another important SPNA in the Bering Sea that covers Karaginskii Island located in Karaginskii Gulf and separated from Kamchatka Peninsula by Litke Strait (Fig. 1(2). At organization of the Reserve "Karaginskii Island" in 1996 all types of commercial catch were prohibited in the water areas around the Island. It was supposed to organize here marine biosphere reserve in succeeding years but the program did not receive financial support. At present Reserve "Karaginskii Island" does not exist any more however the Island is included in the list of wetlands in accordance with Ramsar Convention. There still remains possibility of getting support for the program of organization of marine biosphere reserve on Karaginskii Island, we consider it very expedient because of high

Besides the above-mentioned SPNA-s there are areas within Bering Sea with different

State nature reserve of federal significance "Koryakskii" was founded in 1995 by the Decision of the government of the Russian Federation. The reserve covers a part of Goven

biodiversity of marine flora and fauna of the area that needs protection.

nature protective status aimed at conservation of marine ecosystems:

**5.3 State nature reserve of federal significance "Koryakskii"** 

UNESCO program "The man and the biosphere" (MAB).

also diversity and stability of marine ecosystems).

Islands.

**5.2 Reserve "Karaginskii Island"** 

the floras of south-eastern Kamchatka and western part of Bering Sea is a little less (K**<sup>j</sup>** = 0.63), and it is the least between the floras of the Commander Islands and western continental coast of Bering Sea (K**j** = 0.51). I explain phenomenon of such low similarity (in other words, considerable difference) between floristic complexes of geographically close water areas by peculiarities of the system of ocean currents in this sector of the North Pacific, existence of already mentioned Eastern Kamchatka and Alaska currents (Fig. 1) providing favourable conditions for penetration of invasive species of different origin from the adjacent areas, namely from the Arctic into northern part of Bering Sea and from the American continent to Commander Islands. To tell the truth, such deviations in comparative floristic coefficients may happen due to purely statictical reasons (Kafanov et al., 2004). Nevertheless my conclusions are in agreement with the data of K.L. Vinogradova & L.P. Perestenko (1978) who also showed considerable difference of marine flora of the western Bering Sea from those of the south-eastern Kamchatka and Commander Islands.
