THE NEAR-BOTTOM DISTRIBUTION OF THE GENUS BOREOMYSIS (CRUSTACEA: MYSIDACEA) IN THE PORCUPINE SEABIGHT, NORTH-EASTERN ATLANTIC

P Hargreaves
unpublished
The near-bottom vertical distribution of eight species of the mysid genus Boreomysis (Crustacea) over slope areas of the Porcupine Seabight in the North-eastem Atlantic is described. The numbers of Boreomysis individuals were greatest between 300 m and 1000 m, exceeding 100 per 1000 m3 in three hauls at 400-500 m and 60 per 1000 m3 at 500-1300 m. Below 1300 m numbers decreased rapidly down to the limit of sampling at approximately 3800 m. Within the bathymetric range 300-1300 m each of three
more » ... m each of three numerically dominant suprabenthic Boreomysis species, tended to occupy different optimum depth strata at 400-520 m, 700-950 m and 520-1330 m respectively but overlapped slightly in distribution. In contrast four deeper-living Boreomysis species occurred intermittently near-bottom in the Seabight in the bathymetric range 1300-4000 m. Species distribution over a wide area of the temperate Northeastern Atlantic is discussed. HARGREAVES, P.M. 1997. Distribui@o vertical prdxima do fundo do g6nero Boreomysis (Crustacea: Mysidacea) em "Porcupine Seabight", Atldntico nordeste. Arquipe'lago. CiCncias Bioldgicas e Marinhas 15A: 51-64. Ponta Delgada. ISSN 0873-4704. Descreve-se a distribui@o vertical pr6xima do fundo de oito espCcies de misidhceos do g6nero Boreomysis (Crustacea) sobre zonas de vertente do "Porcupine Seabight" no Atlhtico nordeste. 0 s ntimeros de indivfduos de Boreomysis foram maiores entre os 300 m e os 1000 m, excedendo 100 individuos por 1000 m3 em trEs arrastos a 400-500 m e, 60 indivfduos por 100 m3 a 500-1300 m. Abaixo dos 1300 m o ntimero de individuos decresce rapidamente at6 ao lirnite de amostragem, a 3800 m. Entre os niveis batim6tricos de 300-1300 m cada uma das trEs esptcies suprabhticas de Boreomysis numericamente dominantes tende a ocupar diferentes estratos 6ptimos de profundidade, a 400-520 m, 700-950 m e 520-1330 m respectivamente, embora haja ligeira sobreposi@o na distribui@io. Em contraste, quatro esp6cies de Boreomysis que vivem a maior profundidade ocorreram intermitentemente pr6ximas do fundo em "Seabight", nos niveis de profundidade de 1300-1400 m. Discute-se a distribuic;b das esptcies numa vasta h-ea no Atlhtico nordeste temperado. P.M. Hargreaves,
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