Evaluation of a direct age estimation method for terminally molted male snow crab Chionoecetes opilio (Fabricius 1788) (Decapoda: Brachyura: Oregoniidae)

2020 ◽  
Vol 40 (5) ◽  
pp. 549-555
Author(s):  
April L Rebert ◽  
Gordon H Kruse ◽  
Joel B Webb ◽  
Sherry L Tamone ◽  
Dion Oxman ◽  
...  
Keyword(s):  
Fishery Management ◽  
Estimation Method ◽  
Growth Patterns ◽  
Annual Growth ◽  
Snow Crab ◽  
Gastric Mill ◽  
Age Composition ◽  
Thin Sections ◽  
Chionoecetes Opilio ◽  
Growth Increments

Abstract Recent research suggests that calcified eyestalks and gastric mill ossicles (stomach teeth) can be used to estimate the age of some crustacean species. Along with annual growth of the endocuticle, bipartite bands in the hard tissue are believed to reflect annual growth patterns (similar to fish scales or otoliths) that are retained through repeated molt cycles. Similar bands are observed in the zygocardiac ossicles of the gastric mill from the snow crab (Chionoecetes opilioFabricius 1788). If these bands reflect annual growth, they may be used to estimate age, which could enhance understanding growth, mortality, recruitment, and age composition and improve fishery management. While some studies show that the number of bands correlates to other estimates of age for C. opilio, little evidence suggests that bands accumulate annually as growth increments independent of molting. Male C. opilio terminally molt at maturity, after which they can survive for seven years or more. Shell condition, i.e., degree of wear and epibionts on their exoskeleton, is used here and by other carcinologists as a proxy for age subsequent to the terminal molt. We estimated band counts and endocuticle thickness from thin sections of the zygocardiac ossicle of terminally molted male C. opilio across a range of shell conditions from a wild, fished stock. We found no differences in band counts (P = 0.41) or endocuticle thickness (P = 0.13) across varying shell conditions and size. These results do not support the hypothesis that band counts can be used to estimate the age of this species after the terminal molt.

scholarly journals Discard mortality rates in the Bering Sea snow crab, Chionoecetes opilio, fishery

2015 ◽  
Vol 72 (5) ◽  
pp. 1525-1529 ◽  
Author(s):  
J. Daniel Urban
Keyword(s):  
Mortality Rate ◽  
Bering Sea ◽  
Fishery Management ◽  
Stock Assessment ◽  
Mortality Rates ◽  
Snow Crab ◽  
Commercial Fishing ◽  
Chionoecetes Opilio ◽  
Discard Mortality ◽  
The Bering Sea

Abstract Fish and invertebrates that are unintentionally captured during commercial fishing operations and then released back into the ocean suffer mortality at unknown rates, introducing uncertainty into the fishery management process. Attempts have been made to quantify discard mortality rates using reflex action mortality predictors or RAMP which use the presence or absence of a suite of reflexes to predict discard mortality. This method was applied to snow crab, Chionoecetes opilio, during the 2010–2012 fisheries in the Bering Sea. Discard mortality in the fishery is currently assumed to be 50% in stock assessment models, but that rate is not based on empirical data and is widely recognized to be in need of refinement. Over 19 000 crab were evaluated using the RAMP method. The estimated discard mortality rate was 4.5% (s.d. = 0.812), significantly below the rate used in stock assessment models. Predicted discard mortality rates from the 2010 to 2012 study were strongly correlated with the air temperature at the St Paul Island airport in the Pribilof Islands. Using this relationship, the discard mortality rate from 1991 to 2011 was estimated at 4.8% (s.d. = 1.08).

An Analysis of the Microgrowth Bands in the Shell of the Common MusselMytilus Edulis

1989 ◽  
Vol 69 (2) ◽  
pp. 477-491 ◽  
Author(s):  
C.A. Richardson
Keyword(s):  
Mytilus Edulis ◽  
Growth Patterns ◽  
Structural Elements ◽  
Tapes Philippinarum ◽  
Thin Sections ◽  
Growth Increments ◽  
Hard Shell ◽  
The Common ◽  
Relationship Of ◽  
Improved Methods

The periodicity of microgrowth patterns observed in thin sections and acetate peel replicas of radial sections of bivalve shells are well documented for both intertidal and subtidal species (Pannella & MacClintock, 1968; Rhoads & Pannella, 1970; Evans, 1972, 1975; Kennish, 1980; Richardsonet al., 1979et seq.; Richardson, 1987a, b, 1988, b). In many species daily or tidal lines are well preserved in the shell, for example, the hard-shell clamMercenaria mercenaria(Pannella & MacClintock, 1968), the cockleCerastoderma edule(Richardsonet al., 1979) and the clamTapes philippinarum(Richardson, 1987a, 1988b), while in others they are poorly preserved or lacking. Such an example is the common musselMytilus edulis(L.) where fine growth lines seen in acetate peel replicas have previously been reported to be poorly preserved, with long continuous sequences of such lines seldom occurring (Lutz, 1976). The angular relationship of growth lines to the growing margin and to the crystalline elements of the shell structure are presumed to be the factors influencing the resolution of growth increments (MacClintock, 1967; Pannella & MacClintock, 1968). Pannella & MacClintock (1968) suggest that the larger the angle between depositional surfaces and the structural elements of a shell layer the more evident will be the growth increments. Both oysters and mussels have an unfavourable angular relationship between growth increments and the margin of the shell (Pannella & MacClintock, 1968) and this may explain why the growth lines are difficult to observe. The present paper describes improved methods used to examine the internal micro478 growth patterns in the shell of the common musselMytilus edulisand reports on experiments to investigate the periodicity of the patterns.

scholarly journals Older but not wider. Impacts of molt frequency variation on age and growth dynamics of Newfoundland & Labrador snow crab (Chionoecetes opilio) toward corroborating gastric mill 2 age estimations

2021 ◽  
Author(s):  
Darrell Mullowney ◽  
Nicole O’Connell ◽  
Rémy Rochette ◽  
Raouf Kilada
Keyword(s):  
Estimation Error ◽  
Growth Dynamics ◽  
Age And Growth ◽  
Future Research ◽  
Snow Crab ◽  
Frequency Variation ◽  
Gastric Mill ◽  
Age At Maturity ◽  
Chionoecetes Opilio ◽  
Size At Age

Abstract Aging specimen and survey data from a heterogeneous stock range are combined to investigate effects of molt frequency variation on age and growth dynamics and efficacy of gastric mill age band estimations in snow crab. A central assumption that bands form independent of molting is examined through analyses of molt frequency variation with an overall result of support for the hypothesis that gastric mill bands form independent of molting. This is based on an applied review approach, demonstrating blind age estimation results within and across population units featuring different rates of molt frequency interruptions in context of literature-based expected outcomes of age and growth dynamics. The comprehensive analyses overall supports the ability of gastric mill bands to track chronological ages, but non-fully explained outcomes of growth delays into sexual maturity stages in males and potential estimation error in 1-3 year old crab preclude a conclusion that absolute ages are consistently tracked throughout ontogeny. The results suggest gastric mill bands continue to form during both skip-molts and after terminal molt. Despite uncertainties, the research highlights that males originating from populations where skip-molting is prominent are older reaching fishery size than previously thought (9-10 years), with tentative average estimates of 10-12 years. The study presents novel observations of size-at-age and age-at-maturity in Newfoundland & Labrador (NL) snow crab and broadens life history knowledge for the species. Along with corroborating gastric mill age band estimations, the study reveals future research streams to further help advance the discipline of aging crustaceans [247].

Age and growth of a large tropical anchovy, Thryssa hamiltoni (Gray): A comparison of ageing techniques

1992 ◽  
Vol 43 (5) ◽  
pp. 953 ◽  
Author(s):  
FE Hoedt
Keyword(s):  
Growth Patterns ◽  
Annual Growth ◽  
Age And Growth ◽  
Seasonal Growth ◽  
Length Frequency ◽  
Growth Rings ◽  
Handling Stress ◽  
Growth Increments ◽  
Annual Growth Rings ◽  
Ageing Methods

Three principal ageing methods were used to describe the growth history of Thryssa hamiltoni, a large tropical anchovy from the waters off Townsville, north-eastern Queensland. The study was undertaken to compare ageing methods based on length-frequency analysis that are commonly applied in age and growth studies of tropical clupeoids, with less commonly used methods based on daily and seasonal growth rings in otoliths. A preliminary study suggested that seasonal growth rings in the sagittae of T. hamiltoni were formed annually and were therefore useful for age estimations for this species. Age and growth estimates derived from the three methods were consistent, with the results of each method supporting the results of the others. Direct validation of daily growth increments in T. hamiltoni by means of tetracycline marking experiments was unsuccessful due to the sensitivity of this species to handling stress. The distribution of modes in length-frequency histograms, and age estimates based on annual growth rings, both showed that male and female T. hamiltoni exhibit different growth patterns, with females growing faster and attaining greater maximum lengths than do males. Although counts of annual growth rings suggest a maximum longevity of 4 years for both males and females, lengthfrequency data indicate that the population is largely comprised of fish up to 2 years of age.

scholarly journals 3D enamel profilometry reveals faster growth but similar stress severity in Neanderthal versus Homo sapiens teeth

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kate McGrath ◽  
Laura Sophia Limmer ◽  
Annabelle-Louise Lockey ◽  
Debbie Guatelli-Steinberg ◽  
Donald J. Reid ◽  
...  
Keyword(s):  
Life Stress ◽  
Early Life ◽  
Homo Sapiens ◽  
Normal Growth ◽  
Population Level ◽  
Growth Patterns ◽  
Upper Paleolithic ◽  
Tooth Surface ◽  
Growth Increments ◽  
Anterior Teeth

AbstractEarly life stress disrupts growth and creates horizontal grooves on the tooth surface in humans and other mammals, yet there is no consensus for their quantitative analysis. Linear defects are considered to be nonspecific stress indicators, but evidence suggests that intermittent, severe stressors create deeper defects than chronic, low-level stressors. However, species-specific growth patterns also influence defect morphology, with faster-growing teeth having shallower defects at the population level. Here we describe a method to measure the depth of linear enamel defects and normal growth increments (i.e., perikymata) from high-resolution 3D topographies using confocal profilometry and apply it to a diverse sample of Homo neanderthalensis and H. sapiens anterior teeth. Debate surrounds whether Neanderthals exhibited modern human-like growth patterns in their teeth and other systems, with some researchers suggesting that they experienced more severe childhood stress. Our results suggest that Neanderthals have shallower features than H. sapiens from the Upper Paleolithic, Neolithic, and medieval eras, mirroring the faster growth rates in Neanderthal anterior teeth. However, when defect depth is scaled by perikymata depth to assess their severity, Neolithic humans have less severe defects, while Neanderthals and the other H. sapiens groups show evidence of more severe early life growth disruptions.

scholarly journals Size-at-maturity shift in a male-only fishery: factors affecting molt-type outcomes in Newfoundland and Labrador snow crab (Chionoecetes opilio)

2020 ◽  
Author(s):  
Darrell R J Mullowney ◽  
Krista D Baker
Keyword(s):  
Population Density ◽  
Newfoundland And Labrador ◽  
Cold Water ◽  
Large Male ◽  
Snow Crab ◽  
Size At Maturity ◽  
Chionoecetes Opilio ◽  
Factors Affecting ◽  
Male Density ◽  
Process Factors

Abstract A sex-asymmetric downward shift in size-at-terminal-molt has recently occurred in males in some portions of the Newfoundland and Labrador (NL) snow crab stock range, a first known occurrence for such processes in snow crab (Chionoecetes opilio) stocks. This study examines plausible factors promoting the shift in size-at-terminal-molt [synonymous with size-at-maturity (SaM)] including individual size, temperature, population density, and sex ratio. Analyses highlight expanse of cold water and large male density as being significant predictors of molt-type outcomes. A confluence of cold conditions and low density of large males promoted the SaM shift. In turn, the low male density was associated with recently elevated fishery exploitation rates under quota-controlled management. It remains unknown the extent to which the reduction in terminal size reflects a phenotypic vs. genotypic process. Factors affecting skip-molting in male snow crab are investigated, and we find that skip-molting occurs most frequently under extreme cold and high population density conditions. Potential complications arising from altered growth dynamics are discussed. Overall, the results advance knowledge on intraspecific competition processes within snow crab populations and inform fisheries management systems that male-only harvest strategies do not provide full protection from biological harm to aquatic resources through fishing.

scholarly journals Panmixia in Alaskan populations of the snow crab Chionoecetes opilio (Malacostraca: Decapoda) in the Bering, Chukchi, and Beaufort Seas

2014 ◽  
Vol 34 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Gregory T. Albrecht ◽  
Kris J. Hundertmark ◽  
Alexandra E. Valentin ◽  
Sarah M. Hardy
Keyword(s):  
Snow Crab ◽  
Chionoecetes Opilio

SHELL STRENGTH AND CARAPACE SIZE IN NON-ADULT AND ADULT MALE SNOW CRAB (CHIONOECETES OPILIO)

2000 ◽  
Vol 20 (2) ◽  
pp. 399-406 ◽  
Author(s):  
J-D. Dutil ◽  
C. Rollet ◽  
R. Bouchard ◽  
W. T. Claxton
Keyword(s):  
Adult Male ◽  
Snow Crab ◽  
Chionoecetes Opilio

MARINE BIOGENIC CARBONATES AND RADIOCARBON—A RETROSPECTIVE ON SHELLS AND CORALS WITH AN OUTLOOK ON CHALLENGES AND OPPORTUNITIES

Radiocarbon ◽  
2021 ◽  
pp. 1-16
Author(s):  
Susanne Lindauer ◽  
Carla S Hadden ◽  
Kita Macario ◽  
Thomas P Guilderson
Keyword(s):  
Calcium Carbonate ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Growth Patterns ◽  
Annual Growth ◽  
Environmental Research ◽  
Climate Research ◽  
Marine Carbonates ◽  
Challenges And Opportunities ◽  
Biogenic Carbonates

ABSTRACT Many organisms living in the ocean create tests, shells, or related physical structures of calcium carbonate (CaCO3). As this is most often from dissolved inorganic carbon, using organisms that create calcium carbonate structures for climate research and dating purposes requires knowledge of the origin of carbon that is incorporated. Here, we give a short overview of research on marine carbonates over the last 60 years, especially that based on shell and coral samples. Both shells and corals exhibit annual growth patterns, like trees, and therefore offer possibilities for yearly resolution of past radiocarbon (14C) variations. We concentrate on their evolution in 14C dating including difficulties in determining reservoir ages as well as the possibilities they offer for archaeological dating, oceanography, calibration purposes as well as environmental research in general.

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