Aspects of the distribution, population structure and reproduction of the gastropod Tibia delicatula (Nevill, 1881) inhabiting the oxygen minimum zone of the Oman and Pakistan continental margins
Ramirez-Llodra, E.Z.; Olabarria, C. (2005). Aspects of the distribution, population structure and reproduction of the gastropod Tibia delicatula (Nevill, 1881) inhabiting the oxygen minimum zone of the Oman and Pakistan continental margins. J. Sea Res. 54(4): 299-306. https://dx.doi.org/10.1016/j.seares.2005.06.003
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
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| Keywords |
Distribution
Layers > Core layers (water) > Oxygen minimum layer
Population characteristics > Population structure
Reproduction
Topographic features > Submarine features > Continental margins
Tibia delicatula (G. Nevill, 1881) [WoRMS]
ISW, Oman [Marine Regions]; ISW, Pakistan [Marine Regions]
Marine/Coastal |
| Author keywords |
Tibia delicatula; distribution; population structure; reproduction;oxygen minimum zone; hypoxia; Arabian Sea |
| Authors | | Top |
- Ramirez-Llodra, E.Z., more
- Olabarria, C.
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| Abstract |
The present study describes some aspects of the distribution and biology of Tibia delicatula (Nevill), a gastropod belonging to the family Strombidae. This species has been found in large numbers in the upper oxygen minimum zone (OMZ) of the Oman margin, and has also been collected from the OMZ of the Pakistan margin. The highest abundance of adult specimens in the Oman OMZ was found between 300 and 450 m. Numbers dropped rapidly below 450 m, to zero below 500 m depth. Similarly dense populations were not observed in the Pakistan OMZ. Multiple regression with oxygen concentration and depth indicates that depth (and its related variables) is the main factor explaining the variation in abundance of T. delicatula. The populations from the Oman and Pakistan OMZs were dominated by juveniles. This suggests a unimodal size structure with evidence of a marked recruitment event. Basic reproductive aspects were analysed. All specimens had a penis and sperm groove. The gonad wall consisted of reticular tissue that might be used for nutrient storage or as an irrigation system. Only vitellogenic oocytes were present. The large oocyte sizes observed (200-300 µm) suggest a lecithotrophic larval development. |
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