. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EYESHINE DISTRIBUTION IN DECAPODS II deep-water species (Acanthephyra pelagica and Systelluspis cristata) showed a significant increase in dorsal eyeshine intensity with increasing carapace length. In Oplophorus spinosus, the increase in dorsal eyeshine intensity was less pronounced, and in Systellaspis debilis, as is also demon- strated by Figure 2b, eyeshine actually decreased with in- creasing carapace length. Depth distribution and eyeshine intensity In the present study it was found that for the largest size classes of
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EYESHINE DISTRIBUTION IN DECAPODS II deep-water species (Acanthephyra pelagica and Systelluspis cristata) showed a significant increase in dorsal eyeshine intensity with increasing carapace length. In Oplophorus spinosus, the increase in dorsal eyeshine intensity was less pronounced, and in Systellaspis debilis, as is also demon- strated by Figure 2b, eyeshine actually decreased with in- creasing carapace length. Depth distribution and eyeshine intensity In the present study it was found that for the largest size classes of each of the 19 species examined (Table 1), there were significant correlations between loglo depth and loglo dorsal eyeshine intensity (Fig. 3 a. b). In the case of the relationship between eyeshine intensity and daytime depth, the correlation was markedly improved when Oplophorus spinosus was excluded from the analysis. This species has much higher dorsal eyeshine intensity for its daytime depth distribution than would normally be expected. It is possible that this anomaly is related to the unusually small amplitude of its vertical migration pattern (Foxton, 1970), which sug- gests that this species may be able to light adapt (thereby reducing eyeshine) to some degree. Ventral eyeshine ap- pears to vary independently of depth (Fig. 3 c, d). Analysis of variance showed that migratory species have significantly lower (F = , P = ) log,,, dorsal eyeshine intensity ( ± , n = 13) than nonmigrants ( ± , n = 6). A comparison of ventral eyeshine between the two groups showed that there was no significant difference (F = , P = ) between migratory ( ± ) and nonmigratory species ( ± ). Discussion Eyeshine intensity varies as a result of the efficiency and quantity of reflecting and absorbing pigments within the eye (Gaten et «/., unpubl.). Our examination of mesopelagic decapods has demonstrated that the distribution patterns of their
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
