Allen H Andrews

The Pacific Community | SPC · Department of Fisheries Aquaculture and Marine Ecosystems

Marine fisheries have spread to the deep-sea because the fishes in many of the shallow-water marine habitats have been overexploited. Many studies have found that deep-sea fishes generally grow slowly and can achieve long life spans; however, most age estimates have not been validated. Several methods for validating age and growth estimates have be...

Age determination is a fundamental field of study that is of critical importance to management and conservation of a species. Determining population demographics can only be accomplished with the input of age data; yet, despite years of age determination efforts, it continues to be one of the most challenging and nuanced aspects of life history inv...

Onaga Etelis coruscans is an important component of the commercial deep-water handline fishery in Hawaii and is one of the more valuable species because of its local popularity. This species is part of a management unit called the Deep 7, a data-poor fishery comprising six snapper and one grouper species for which information about age, growth, lon...

Coral skeletal structures can provide a robust record of nuclear bomb produced ¹⁴C with valuable insight into air-sea exchange processes and water movement with applications to fisheries science. To expand these records in the South Pacific, a coral core from Tutuila Island, American Samoa was dated with density band counting covering a 59-yr perio...

Supplemental Material – Andrews et al. (2019) Growth and longevity of Hawaiian grouper (Hyporthodus quernus) — input for management and conservation of a large, slow-growing grouper. Additional information on specimens and measurements made in the associated published work. Plots of otolith mass-to-TL (used as a tool in elucidating accurate growth...

Herring and sprat are estimated to live more than 20 years in the Baltic Sea by counting growth zones in otoliths. Our study established a new bomb radiocarbon chronology — a signal that was created by atmospheric testing of thermonuclear devices in the 1950s and 1960s — for the region that was used to validate age estimates of 2-18 years for sprat...

Age-reading protocols for tuna species using annual growth zones in thin-cut transverse otolith sections have produced greater age estimates than previous methods. Lifespan estimates for yellowfin (YFT) and bigeye (BET) tuna (Thunnus albacares and T. obesus) were validated up to 16–18 years in the western North Atlantic Ocean using bomb 14C dating...

Context. The potential lifespan of alligator gar (Atractosteus spatula) is currently unknown. A previous study applied bomb radiocarbon (14C) dating to establish ages >60 years, but maximum age was limited by the rise of bomb-produced 14C in the 1950s. Aims. An exceptionally large specimen (2.6 m, 148 kg) was captured in Mississippi and otolith gro...

The Pacific sleeper shark Somniosus pacificus is a large-bodied and broad-ranging squaliform shark that occupies diverse habitats throughout the Pacific Ocean. Despite its large size and occurrence as bycatch in various commercial fisheries, little is known about even the most basic aspects of its biology and ecology. Observed declines in certain p...

Otoliths of splendid alfonsino (Beryx splendens) are primarily aged using whole otoliths by viewing the distal surface with reflected or transmitted light. Growth zone structure in this view is well defined and maximum age estimates cover 10–25 years from studies across the world. Its congener, the red bream (B. decadactylus), is also aged in this...

Bomb radiocarbon dating was originally developed as a tool for determining or validating the age of marine and freshwater organisms using the rise of bomb-produced radiocarbon in the 1950s and 1960s. Use of this signal is becoming more limited because the organism must have lived through this period to place constraints on age — either the lifespan...

Six species of redhorse sucker (family Catostomidae, genus Moxostoma) occur in Minnesota, and all are harvested recreationally, particularly by bowfishing. Currently, this group is managed collectively as a single stock, yet contemporary data on life history, harvest levels, and population dynamics have not been analyzed. For years 2018–2021, we co...

This paper describes the results from a feasibility study to investigate the potential to establish known ages for a set of school shark that can be used to calibrate an epigenetic age clock for school shark. A close kin mark-recapture study showed that vertebral ages for school shark, which were known to be biased for mature shark, are poorly esti...

Stock assessments for Shovelnose Sturgeon have largely been limited to age and growth analyses using pectoral fin rays despite potential underestimation of age and lack of age validation. Fisheries stock assessments rely on accurate estimates of vital rates for effective fisheries management, within which fish age and lifespan are of primary import...

Reproductive characteristics of a fish stock provide important tools for assessing population health. Change in length-at-maturity (L50 ) is a potential indicator of exploited fish populations but when criteria for determining maturity classifications are inconsistent, it is difficult to accurately assess change over time and space. Etelis coruscan...

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Age and growth investigations for shovelnose sturgeon (Scaphirhynchus platorynchus) are largely limited to traditional methods of reading growth zone structure in pectoral fin ray sections. Age reading has been imprecise and when validated with marginal increment analysis, authors have recommended other forms of age validation. In this study otolit...

The lifespan of fishes is an important factor in having a proper understanding of life history and survivorship strategies. In many cases, the longevity of fishes have been greatly underestimated with dire consequences to fish populations and fishery sustainability. While it is fun to land large fish as a sport, we need to start thinking about leav...

Graphical abstract for our recent publication on the use of otoliths in fisheries science.

Chemical analysis of calcified structures continues to flourish, as analytical and technological advances enable researchers to tap into trace elements and isotopes taken up in otoliths and other archival tissues at ever greater resolution. Increasingly, these tracers are applied to refine age estimation and interpretation, and to chronicle respons...

The International Commission for the Conservation of Atlantic Tunas (ICCAT) concluded the Atlantic Ocean tropical Tuna Tagging Programme (AOTTP) in 2021. This project had the objectives of enhancing food security, stimulating economic growth, and improving management through research on tropical tuna resources in the Atlantic Ocean, including bigey...

This paper describes the progress made for Project 105 aimed at using bomb radiocarbon (14C) dating to test the validity of age estimates from purported annual growth zones in otolith sections of yellowfin (YFT) and bigeye (BET) tuna of the western central Pacific Ocean. A total of 123 otoliths were selected from archived young-of-the-year (yoy) sa...

We cannot properly manage aquatic ecosystems if we do not understand how the fishes within live and grow. Age and growth can be estimated, but often ages have been proven incorrect with catastrophic results for the fishery. Perhaps the only good thing about nuclear bombs that were tested in the 1950s and 1960s is that we can use a global radiocarbo...

Despite decades of commercial harvest of bigmouth buffalo (Ictiobus cyprinellus) from Jamestown Reservoir, North Dakota, and the recent rapid growth of sport bowfishing that targets this species, there is a lack of biological information on this native catostomid. At present, no-limit recreational and commercial harvest of bigmouth buffalo occurs i...

The reproductive characteristics of the longtail snapper, Etelis coruscans — known locally in Hawaii as “onaga,” — was last assessed in 1989; therefore, updated information is needed for improving its stock assessment and management in the bottomfish fishery of the main Hawaiian Islands (MHI). Specimens were collected during research cruises and ei...

The supporting information provided is an extended table listing all nuclear tests conducted at Bikini and Enewetak atolls (S1) and a movie that provides a visual on the close-in fallout current modeling. See associated article for details on its application in the study. LINK CORRECTION: https://youtu.be/1D-FT0wVajo MODELING: Close-in fallout of...

Gindai (Pristipomoides zonatus) is one of six snappers in a management complex called the Deep 7 of the Hawaiian Islands. Little is known about its life history and a preliminary analysis of otolith thin sections indicated the species may exhibit moderate growth with a lifespan approaching 40 years. Preliminary age estimates from the previous study...

Oceanic whitetip sharks Carcharhinus longimanus are a cosmopolitan epipelagic species that was once prolific throughout the tropics and subtropics but was recently listed as Critically Endangered by the International Union for the Conservation of Nature and as Threatened under the United States Endangered Species Act. Although historically conspicu...

Considerable efforts have been undertaken to characterize population dynamics of the Alligator Gar Atractosteus spatula. Accomplishing this task required identifying suitable structures to estimate age. Buckmeier et al. (2012) validated sagittal otoliths to 31 years — the oldest fish in their study. However, they noted that interpreting annuli beca...

A workshop on bomb radiocarbon age validation for tuna and billfish in the Western and Central Pacific Ocean (WCPO) was held in early July 2020. Experts in otolith ageing and bomb radiocarbon methods discussed the encouraging results from preliminary radiocarbon work for tuna and agreed that the application of radiocarbon methods to validate age es...

The largest of the ulua species in Hawaii — known locally as ulua aukea (white ulua) or as giant trevally (Caranx ignobilis) throughout its Indo- Pacific distribution — is an iconic reef fish that attains its greatest size in the Hawaiian Islands. They have a broad range that extends from Hawaii to the central South Pacific, through the Indo-Pacifi...

This is a Zoom presentation I provided to Swedish University of Agricultural Sciences (Sveriges lantbruksuniversitet) on the latest in bomb radiocarbon dating and how the method may be used for marine and freshwater species of Scandinavia and the Baltic Sea. I provide my presentation on new findings for yellowfin and bigeye tuna longevity (approa...

The otoliths (ear stones) of fishes are commonly used to describe the age and growth of marine and freshwater fishes. These non-skeletal structures are fortuitous in their utility by being composed of mostly inorganic carbonate that is inert through the life of the fish. This conserved record functions like an environmental chronometer and bomb-pro...

Onaga is prized among fishers of the Hawaiian Islands and it is a difficult fish to catch, even by those with the know-how. Its brilliant red color and long tail fins make it popular as a culinary display for celebratory banquets (see Lawai’a Magazine No. 11). Late in the year, the landings and value of onaga increase during the holiday season. The...

Giant trevally (Caranx ignobilis) are an iconic reef fish of the Indo-Pacific, and yet knowledge of their life history is incomplete. The species is common in tropical and subtropical waters ranging from the far western Indian Ocean off South Africa to the central Pacific Ocean, where the species attains its greatest recorded size in Hawaii. Despit...

Estimates of age and growth of yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tuna remain problematic because validation of growth zone deposition (opaque and translucent) has not been properly evaluated. Otolith growth structure (zone clarity) can be poorly defined for tropical tunas, but the use of bomb radiocarbon dating has validated...

Popular article on the published scientific research for Hawaiian grouper (Hyporthodus quernus) that I wrote for Lawai'a Magazine, a local fishers magazine that shares the latest in fishing news for the Hawaiian Islands. Related scientific article: https://doi.org/1o.1139/cjfas-2018-0170

Little is known about long-term changes in coral reef fish communities. Here we present a new technique that leverages fish otoliths in reef sediments to reconstruct coral reef fish communities. We found over 5,400 otoliths in 169 modern and mid-Holocene bulk samples from Caribbean Panama and Dominican Republic mid-Holocene and modern reefs, demons...

Understanding the age structure and population dynamics of harvested species is crucial for sustainability, especially in fisheries. The Bigmouth Buffalo (Ictiobus cyprinellus) is a fish endemic to the Mississippi and Hudson Bay drainages. A valued food-fish for centuries, they are now a prized sportfish as night bowfishing has become a million-dol...

Bomb-produced 14C has been used to make valid estimates of age for various marine organisms for 25 years, but fish ages that lead to birth years earlier than the period of increase in 14C lose their time specificity. As a result, bomb 14C dating is limited to a minimum age from the last year of prebomb levels because the temporal variation in 14C i...

Hawaiian grouper (Hyporthodus quernus) is endemic to the Hawaiian Islands and is regionally important, yet little is known about its life history. This large species is managed within the Deep 7 bottomfish complex, which includes six snapper species that are assumed to have similar life history traits. Previous age estimates were not validated and...

A previous study that explored the age and growth of red steenbras Petrus rupestris (Valenciennes, 1830), a large sparid (family Sparidae, seabreams or porgies) endemic to South Africa and reported to approach 2 m in length, provided estimates as a moderately slow-growing species with a maximum age near 30 years. The stock is considered collapsed a...

Popular article that I wrote about providing the first valid estimate of longevity using bomb radiocarbon dating on this blue marlin for the local fishers of Hawaii. Research Article: Andrews, A.H., R.L. Humphreys, and J.D. Sampaga. 2018. Blue marlin (Makaira nigricans) longevity estimates confirmed with bomb radiocarbon dating. Canadian Journal...

Hadal trenches are isolated habitats that cover the greatest ocean depths (6,500-11,000m) and are believed to host high levels of endemism across multiple taxa. A group of apparent hadal endemics is within the snailfishes (Liparidae), found in at least five geographically separated trenches. Little is known about their biology, let alone the reason...

The longevity of blue marlin (Makaira nigricans) remains unresolved. The use of fin spines and sagittal otoliths for age reading has led to unconfirmed longevity estimates near 20–30 years. Age validation has been elusive because large individuals are uncommonly caught, and a technique that can be applied to structures that provide estimates of age...

Growth rates and longevities were estimated for five major fishery species of parrotfishes (“uhu”) at Oahu, Hawai’i. All species grew rapidly with von Bertalanffy growth formula k values ≥0.4·year⁻¹. Longevities were found to range broadly among the three small species, 4 years in Calotomus carolinus and 6 and 11 years in Scarus psittacus and Chlor...

Deep-water corals are some of the slowest growing, longest-lived skeletal accreting marine organisms. These habitat-forming species support diverse faunal assemblages that include commercially and ecologically important organisms. Therefore, effective management and conservation strategies for deep-sea corals can be informed by precise and accurate...

This is a seminar I presented at Sveriges lantbruksuniversitet (Swedish University of Agricultural Sciences) or the Department of Aquatic Resources, Institute of Freshwater Research in Drottiningholm (near Stockholm), Sweden. I covered the work I have been doing in validating the age, growth and longevity of fishes and other marine organisms usin...

The green jobfish Aprion virescens (Hawai’i local name, uku) is an economically important component of Hawai’i’s spearfishing, trolling, and deep handline fisheries (largest total poundage landed and third most valuable non-pelagic species). However, stock status of this large-bodied lutjanid has not been determined since 1990 and a primary reason...

High-resolution radiocarbon (14C) analyses on a coral core extracted from Guam, a western tropical Pacific island, revealed a series of early bomb-produced 14C spikes. The typical marine bomb 14C signal—phase lagged and attenuated relative to atmospheric records—is present in the coral and is consistent with other regional coral records. However, 1...

A new instrumental setup, combining laser ablation (LA) with accelerator mass spectrometry (AMS), has been investigated for the online radiocarbon ((14)C) analysis of carbonate records. Samples were placed in an in-house designed LA-cell and CO2 gas was produced by ablation using a 193 nm ArF excimer laser. The (14)C/(12)C abundance ratio of the ga...

Bluespine unicornfish (Naso unicornis) from Hawaii were aged to >50 years using cross-sectioned sagittal otoliths. Fish length was a poor indicator of age because of rapid and variable early growth, exemplified by fish aged to be 4 years near maximum length. Growth was deterministic with adult ages decoupled from body length. Otolith mass and thick...

Corals of the Hawaiian Archipelago are well situated in the North Pacific Gyre (NPG) to record how bomb-produced radiocarbon has been sequestered and transported by the sea. While this signal can be traced accurately through time in reef-building corals and used to infer oceanographic processes and determine the ages of marine organisms, a comprehe...

Some of the most basic questions of sea turtle life history are also the most elusive. Many uncertainties surround lifespan, growth rates, maturity and spatial structure, yet these are critical factors in assessing population status. Here we examine the keratinized hard tissues of the hawksbill (Eretmochelys imbricata) carapace and use bomb radioca...

Black cardinalfish (Epigonus telescopus, Apogonidae) is an important component of deepsea commercial fishing activity in the New Zealand region. It is estimated to live longer than 100 years on the basis of counts of unvalidated annual growth zones in otoliths. Age-validation procedures for long-lived fishes are often one of the following two techn...