Bathymetric gradients of fecundity and egg size in fishes: A Mediterranean case study. (October 2016)

• Record Type: Journal Article
• Authors: Fernandez-Arcaya, Ulla; Drazen, Jeffrey C.; Murua, Hilario; Ramirez-Llodra, Eva; Bahamon, Nixon; Recasens, Laura; Rotllant, Guiomar; Company, Joan B.
• Is Part Of: Deep sea research. Volume 116(2016)
• Page Start: 106
• Page End: 117
• Publication Date: 2016-10
• Subjects: Deep sea -- Fish -- Fecundity -- Egg size -- Reproductive output -- Bathymetric pattern Mediterranean Sea -- Isothermal; Oceanography -- Periodicals; Océanographie -- Périodiques; 551.4605
• DOI: 10.1016/j.dsr.2016.08.005
• Languages: English
• ISSNs: 0967-0637

Abstract

Abstract: There is a general hypothesis that species inhabiting deep-sea waters have lower fecundity and larger eggs than shallower species. However, there are few comparative studies which explore this trend because of the complexity of sampling in deep waters, especially in fishes. We present here the first analysis of fecundity and egg size with depth along an isothermal environment. We calculate the relative fecundity and egg size of 11 species of demersal deep-sea fish from the western Mediterranean and included in our analyses published data for an additional 14 species from the same geographic area. The results show that the relative fecundity (eggs per g of individual) of the analyzed fishes slightly decreased along the bathymetric gradient, whereas egg size increased with depth. When the analysis was conducted including only species from the order Gadiformes, the most speciose group in the region and with the widest depth range of distribution (50–2000 m), there was no relationship between relative fecundity and depth, while the deepest species had larger egg sizes than shallower ones. The finding of similar relative fecundities but larger egg sizes suggests that these deep-sea species are investing a higher amount of energy in the production of offspring than shallower water counterparts. The results are discussed in relation to the isothermal characteristics of the deep Mediterranean Sea and ecological adaptations for reproductive success. Highlights: First data on fecundity and egg size of 11 deep-sea fish. Asses the bathymetric trend of fecundity and eggs size in the W Mediterranean fish. Deep-sea fishes showed similar relative fecundities but larger egg sizes. Rather than temperature other factors could be the drivers of the observed trends.