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Craig Longmore School of Biology & Environmental Science |
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Looking to the deep:
Using otolith microchemistry to determine the spatio-temporal
connectivity in deep-sea teleosts
With the decline of traditional commercial fisheries in recent years, attention has turned to the harvesting of deep-sea fish. However, due to over-exploitation, the majority of these fisheries are now in decline and are proving to be unsustainable. Therefore careful management of these stocks is essential and this requires an intimate knowledge of the underlying demographic and life-history characteristics of deep-sea species.
This study will look at two commercially important deep-sea fish; the roundnose grenadier, Coryphaenoides rupestris and black scabbardfish, Aphanopus carbo.Trace element signatures in the otoliths of these fish represent the most powerful natural markers in addressing spatial questions in fish population dynamics, as the microchemical composition of the continuously growing otolith reflects the chemical characteristics of the environment inhabited by the fish at a given point in life.
I will use inductively-coupled plasma mass spectrometry (ICP/MS) to assess if environmental differences across the regions investigated are reflected in the elemental composition of otoliths. The otolith microchemistry will then be compared with the genotypic information for the very same individual fish representing a very powerful strategy to investigate population structure and one that is seldom put in practice. The patterns inferred will be interpreted in view of the life-history traits of each species as well as comparing spatial population structure with oceanographic models.
This study may prove pivotal for both the Irish and European deep-sea fishery through the future identification of distinguishable stocks, separated spawning grounds, and possibly different deep-sea domains in need of special management.
Supervisor: Stefano Mariani
Publications:
Jovanovic, B., Longmore, C., O’Leary, A. & Mariani S., 2007. Fish community structure and distribution in a macro-tidal inshore habitat in the Irish Sea Estuarine Coastal & Shelf Science 75, 135-142
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