August 4, 2004
by Will Patterson
William F. Patterson III, PhD, is an Assistant Professor in the Department of biology at the University of West Florida. He is a specialist in marine fisheries ecology. He is serving as the principal investigator for the marine vertebrate component of the Deepwater Gulf project.

I have already lost track of time and date although we are only a few days into a nearly three-week research cruise.  I do know we spent the last two days conducting archeological and biological sampling at the Halo shipwreck site in nearly 500 ft of water.  I have had an interest in history for as long as I can remember, and even contemplated a career as a historian while an undergraduate, but the reason I signed on to this expedition was to sample deepwater reef fishes on the northern Gulf of Mexico (Gulf) outer shelf and slope.  And from a fish biologist’s perspective, our sampling at the Halo was very productive.

	Yellowfin Bass Anthias nicholsi
	Roughtongue Bass Pronotogrammus martinicensis
	Red Barbier Hemanthias vivanus

Anthiinae basses collected at the Halo shipwreck site. Image by Will Patterson.

One of my research interests has been the ecology of natural and artificial reef ecosystems in the northern Gulf.  On this cruise, our (graduate student Nicole M. B. Morris’ and my) objective is to sample fish communities on and away from shipwreck sites to estimate the function of wrecks as artificial reefs in moderately to very deep waters.  Of the sites we will visit, the first few offer the greatest opportunity to sample true northern Gulf reef fishes.  Video from the sites will allow us to test if the fish community is significantly different on versus away from (approx. 1000 ft out) wrecks, but we also are sampling fishes with fish traps and a suction sampler engineered by the SonSub ROB crew.  We have had some previous experience with traps, but the new suction sampler has been instrumental in sampling small basses (close relatives of groupers) associated with deepwater corals attached to wrecks.    

Method for extracting otoliths (earstones) from and ageing reef fishes. The fish on the left is an adult red snapper, Lutjanus campechanus, which was about 400mm (one foot four inches) total length.  One of its sagittal otoliths (about 3cm, or one inch, along its long axis) was removed from its head and is shown at right. The otolith is then cut into a thin section (red lines). Image by Willy Bemis.

At left, a digital image of a thin section prepared of the otolith viewed with transmitted light.  Opaque zones counted along the grove in the otolith, known as the succal grove, number 5.  Therefore, this fish was five years old when captured. Image by Andy Fischer.

Will Patterson looks over a sample from the ROV.

A significant portion of Nicole Morris’ master’s thesis will be estimating the age and growth of deepwater reef fishes as well as the level of the food web they occupy.  We have been collecting otoliths, or ear stones, from all the fish sampled.  These mostly calcium carbonate structures contain a wealth of information about the age of fish, as bony fishes lay down growth rings in them that can be used to estimate daily age in larvae and juveniles and annual age in adults.  In this study, Nicole will section otoliths to estimate the age structure of fish populations on and away from wrecks.  We also are collecting fish muscle tissue to analyze stable isotopes of C, N, and S.  From these analyses, Nicole will estimate trophic levels fishes occupy, as well as source(s) of carbon to deepwater wreck communities.  Thus far, our sampling is going very well and we owe a great debt of gratitude to both the HOS Dominator and SonSub crews for their incredibly diligent work in helping us collect samples.  I have been thoroughly impressed with their dedication and innovation during the first few days of this project and feel very fortunate C&C Technologies, MMS, and NOAA were able to contract their services.

Jimmy Moore holds a juvenile shark.

Sunset over the wreck of Halo.