Colonization of the deep sea by fishes.
Bottom Line: Analysis of maximum depth of occurrence of 11 952 marine fish species shows a global decrease in species number (N) with depth (x; m): log10 N = -0·000422x + 3·610000 (r(2) = 0·948).The slopes for the Classes Myxini (-0·000488) and Actinopterygii (-0·000413) follow this trend but Chondrichthyes decrease more rapidly (-0·000731) implying deficiency in ability to colonize the deep sea.Deep-sea invasive families such as Ophidiidae and Liparidae make the greatest contribution to fish fauna at depths >6000 m.
Affiliation: Oceanlab, Institute of Biological and Environmental Sciences, University of Aberdeen, Main Street, Newburgh, Aberdeen AB41 6AA, U.K.Show MeSH
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Mentions: The Actinopterygii comprise 33 orders arranged in the phylogenetic sequence shown in Table1. The sequence from FishBase was used, which is based on a preliminary phylogeny, ranking species according to the presumed age of their common ancestor at least to their order level and within order and family wherever possible (Preikshot et al., 2000). Within each genus, species are ranked alphabetically. The relationship between maximum depth of occurrence and species rank is shown in Fig. 4. Whilst most species of Actinopterygii occur shallower than 500â€‰m, the vertical linear clusters of points indicate taxa that have extended their range into the deep sea beyond 1000â€‰m depth. There is a general trend that these and the maximum depths attained both decrease with increase in phylogenetic rank number. This is reflected in the linear fitted trend line indicating a decline in species depth: yâ€‰= âˆ’0Â·0711xâ€‰+â€‰1104Â·0000 (r2â€‰=â€‰0Â·125), where y is depth in m and x is species taxonomic rank number. Although the correlation coefficient is low (i.e. there are other explanatory variables), the very large sample size (10 695) makes the effect of phylogeny highly significant (P < 0Â·001). It is interesting to note that the trend is also significant within the Acanthopterygii.
Affiliation: Oceanlab, Institute of Biological and Environmental Sciences, University of Aberdeen, Main Street, Newburgh, Aberdeen AB41 6AA, U.K.