Age and Longevity Research

 
 

My work on determining the age and longevity of marine organisms began with explorations of the deep sea off the Farallon Islands near San Francisco, California.  I was fortunate as an early graduate student at Moss Landing Marine Laboratories in the Ichthyology Lab to be involved in a contract with the US Navy to perform deep sea tows and camera sled operations in 2,000 to 3,300 m of water.  Little was known from these depths and especially in this region.  We encountered numerous marine organisms from bottom trawls that took nearly 2 hours to reach the bottom and many of the animals were new to science.  The fishes we encountered were from several major deep sea families and most notable for me were the grenadier or rattails (family Macrouridae). 


The Pacific grenadier (Coryphaenoides acrolepis) was the species of choice for my MS thesis for several reasons.  Little was known about this fish and it was beginning to show in the local markets as a new fresh fish from the deep waters of California to Washington.  According to a series of published papers that dated back to 1957, longevity was anywhere from 6 to more than 60 years.  This was a major discrepancy in terms of having a proper understanding of the life history of this species.  I was concerned that if the new fishery was successful there would be little to rely on for proper management and development of a sustainable fishery.  The question of accurate age and growth needed to be answered.


In concert with the work I was doing with the US Navy contract, two other students were working on their theses in applying a new technique to determine the age of long-lived fishes.  Diane Watters and Donna Kline were working with Gregor Cailliet and Kenneth Coale to apply a radiometric approach (lead-radium dating) as an independent measure of age for bank rockfish (Sebastes rufus) and shortspine and longspine thornyheads (Sebastolobus alascanus and S. altivelis), respectively.  Because estimated longevity of the Pacific grenadier differed by up to a factor of 10, the method was well suited to answer the question of what age estimate interpretation was accurate.


The radiometric method that I have utilized is referred to as lead-radium dating, a geochemical phrase that I prefer to use because of its specificity to the application.  Lead-radium dating of fishes has led to a similar application to deep-sea corals called lead-210 dating. In concert with this work, another kind of application for independent age estimation, bomb radiocarbon dating, was explored and has been applied successfully to marine fishes and invertebrates.


The aim of this website is to present this research and how it has evolved from my first successful application to the Pacific grenadier to innovative applications in other lines of research with deep sea corals and bomb radiocarbon dating.  I have been very fortunate with a productive pursuit of this work and have had the honor of working with many researchers from all over the world. I am greatly appreciative for their assistance, collegiality, and friendship over the years.  I am very proud of our achievements and I hope you enjoy this presentation.  



 

Research background (CV2020 August-AHAndrews.pdf)