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Maximum ages of groundfishes in waters off Alaska and British Columbia and considerations of age determination
... Shortraker rockfish age determination has been attempted with resolved methods common to other Scorpaenids, but interpretation of growth zones is problematic with low precision between age readers (Hutchinson et al. 2007). Shortraker rockfish are thought to have a lifespan as high as 150 years (Munk 2001), which can exacerbate age reading difficulty. Radiometric age validation, using the ratio of 210 Pb/ 226 Ra in otoliths, confirms that they are long lived (Kastelle et al. 2000;Hutchinson et al. 2007). ...
... Therefore, this study is the first to independently confirm age estimates of redstripe rockfish, with a maximum validated age of 36 years. Maximum estimated ages of 46 and 55 years have been reported previously for this species from the Gulf of Alaska (Alaska Fisheries Science Center 2017) and British Columbia (Munk 2001) waters respectively. Although it is generally not appropriate to extrapolate beyond those in the study, these previous studies used age determination methodology similar to ours and therefore it could be reasonably assumed that their reported maximum ages are also accurate. ...
... In our study the estimated maximum age of shortspine thornyhead and shortraker rockfish was 49 and 59 years respectively from specimens chosen to coincide with the era of increasing bomb-produced D 14 C, not the maximum age available. Maximum ages reported elsewhere are up to 89 and 157 years for shortspine thornyhead and shortraker rockfish respectively (Munk 2001; Alaska Fisheries Science Center 2017). Using radiometric age validation, ages older than observed in this study were confirmed as generally accurate for both species (Kline 1996;Kastelle et al. 2000;Hutchinson et al. 2007). ...
In rockfish (Family Scorpaenidae), age determination is difficult and the annual nature of otolith growth zones must be validated independently. We applied routine age determination to four species of Gulf of Alaska rockfish: two shallower-water species, namely harlequin rockfish (Sebastes variegatus) and redstripe rockfish (Sebastes proriger), and two deep-water species, namely shortspine thornyhead (Sebastolobus alascanus) and shortraker rockfish (Sebastes borealis). The estimated ages (counts of presumed annual growth zones in the otoliths) were then evaluated with bomb-produced radiocarbon (14C) and Bayesian modelling with Markov chain Monte Carlo simulations. This study successfully demonstrated the level of accuracy in estimated ages of redstripe rockfish (a 35% probability of underageing, and ~5% probability of overageing) and harlequin rockfish (a 100% probability that they were underaged by ~3 or 4 years). Measured Δ14C in shortspine thornyhead and shortraker rockfish otoliths was lower and increased later than expected. Hence, incorrect age determination could not be evaluated. This is likely caused by dissimilar environmental and biological availability of 14C between these two species and the Pacific halibut (Hippoglossus stenolepis) reference chronology, or underageing of these two species.
... Rockfishes are some of the longest-lived fishes known in Puget Sound, with maximum ages for several species spanning more than 50 years. Elsewhere in their range, rockfishes can attain ages between 100 years and 205 years (Munk 2001). Although many general life history traits are known for the Sebastes genus, few species have been studied in detail, especially in Puget Sound. ...
... Most rockfish species have maximum longevities ranging from several decades to over 100 years in age. The rougheye rockfish can live to 205 years (Munk 2001). In contrast, the small Puget Sound rockfish lives to 22 years in some areas, but only thirteen years in Puget Sound, and only attains lengths of 18 cm (Beckman et al. 1998). ...
... This North Sound age determination was made by the surface-reading technique and likely underestimated the true age. Copper rockfish reach a maximum age of 50 years in Alaska (Munk 2001). Ninety percent of the copper rockfish were between 3 years and 15 years in age in North and South Sound (Figure 6.3). ...
... Age readers disagree on the general interpretation of these growth patterns by up to ,20 years. One interpretation describes a young-fish scenario -a lifespan near 12-14 years (Johnston and Anderl 2012) -whereas another interpretation describes an old-fish scenario -ages up to 25 years (Munk 2001) and in this study otolith interpretation exceeded 30 years. Hence, age validation of Pacific cod is of paramount importance for proper stock assessments and fisheries management. ...
... Applicable to the Pacific cod scenario is a lead-radium dating study on walleye pollock (Theragra chalcogramma). The estimated age scenarios were similar in that the maximum age for the youngfish scenario was near 12-14 years (Kimura and Lyons 1991) and for the old-fish scenario was approaching 30 years (Munk 2001). Lead-radium dating of walleye pollock was definitive in its validation of the young-fish scenario (Kastelle and Kimura 2006). ...
Age readers disagree on the age reading interpretation of otolith growth patterns for the Pacific cod (Gadus macrocephalus). One interpretation describes a young-fish scenario with a life span near 10-12 years, whereas another interpretation describes an old-fish scenario at more than 30 years. In this study, lead-radium dating was performed on Pacific cod otoliths to test the validity of the old-fish age reading scenario. Radiometric ages revealed that the young-fish scenario was valid because the actual age of the two oldest adult groups was more than 20 years younger than estimated by the old-fish scenario.
... Consequently, after the introduction of otoliths sectioning, impressive ages have been recognised in some species (up 205 y! in Sebastes; Munk, 2001). ...
... Beside the immortality hypothesis by Bidder (Bidder, 1932, in Beverton & Holt, 1959, and Reznick et al., 2002, it is interesting to wonder about modern scientist's inclination with reference to the issue of marine animals' life span. As a matter of fact modern researchers consider marine life spans longer than previously believed: up 405 years (y) in bivalves, 72 y in decapod crustaceans, 226 years in fishes, 190 years in tortoise and 211 y in whales (Nigrelli, 1959;Das, 1994, Patnaik et al., 1994Woodhead, 1998;Carey & Judge, 2000;Morales-Nin, 2001;Cailliet et al., 2001;Munk, 2001;Vogt, 2012;Guerin, 2006;Cailliet & Andrews, 2008). ...
The use of hard structures to age bony fish traditionally has been considered as the best routinely applied practice to estimate stock growth pattern and life span, especially in species exhibiting an almost continuous recruitment. Along with progress in fish biology knowledge and technological advances in hard structures reading and validation, problems related to this practice emerged and contrasting age estimate interpretations occurred. Attempts of age validation by different methods did not help in solving the problem and even resulted in increased uncertainties. Accordingly, scientists belonging to different research current/branch supported age estimations differing substantially for the same species, but no proper checking about how these contrasting figures eventually matched other life history parameters was carried out. Aim of this study is to suggest a method to check which lifespan estimate may be more appropriate in building up a less risky management plan, by comparing different age estimates results in relationship with other main lifespan parameters. The method was applied to one of the most famous debate in fisheries history, i.e., the growth pattern of the "white" European hake (herein Hake), Merluccius merluccius L.. Hake is one of the most important species for the Mediterranean fisheries, alternatively described as a slow growing (herein Methuselah) vs fast/sprinter-growing (herein Butterfly) fish. The analysis of data collected between 1990 and 2013 in the GFCM geographical sub-area n 16 (GSA 16, South of Sicily) indicates that both scenarios are unlikely, even though the Methuselah pattern looks more adequate to the situation as described by data, at least from a precautionary management point of view. Results suggest that a two-phase (two-stanza) growth pattern (or analysing separately recruits/juveniles from adults/spawners) might be the proper compromise for Hake assessment and management, at least for the stock exploited off South of Sicily fishing grounds.
... Pacific halibut Hippoglossus stenolepis is one of the largest studied species; it may reach the body length (FL, by Smith) 267 cm, the body weight 363 kg, and the age 55 years. Ultra-large fish are caught rarely, but the specimens FL 100−180 cm and body weight of up to 100 kg are found quite frequently, especially in the Bering Sea and Gulf of Alaska (The Pacific Halibut..., 1998;Munk, 2001;Mecklenburg et al., 2002;Fadeev, 2005). The report on the catch of the Pacific halibut FL 470 cm and body weight 423 kg (Fadeev, 1986(Fadeev, , 1987The Pacific Halibut..., 2014) was not documented officially. ...
... The spawning period of the northern rock sole starts in winter and ends in June (Pertseva-Ostroumova, 1961). According to our data, the spawning and recently spawned specimens are also found in August, (Fadeev, 1987;Munk, 2001). In the northwestern Bering Sea, these flounders are smaller and more elongated compared to the northern rock sole and the Alaska plaice. ...
Biological features of the seven abundant commercial species—the Pacific halibut Hippoglossus stenolepis, the Greenland halibut Reinhardtius hippoglossoides, the Alaska plaice Pleuronectes quadrituberculatus, the northern rock sole Lepidopsetta polyxystra, the yellowfin sole Limanda aspera, the flathead sole Hippoglossoides elassodon, and the Bering flounder H. robustus (Pleuronectidae)—have been studied for a 20-year period (1995−2015). These species are present in the northwestern Bering Sea in the summer–autumn season; they form the gatherings in Olyutorsky-Navarin region. The size-weight spectra of the fish caught by different fishing gear has been analyzed, the peculiarities of the linear growth and the weight gain, as well as the spawning period and scale and the spawning conditions, have been described. The largest halibut specimens have been registered in the bottom setlines and gill nets, while flounders were in snurrevad catches; the smallest specimens have been observed in trawl catches. The abundant year-class in most of the studied species is seen well on the long-term plots of the fish size spectra and is tracked by the decrease of their biological parameters. The species that demand vast growing grounds (Pacific halibut, Alaska plaice, northern rock sole, and yellowfin sole) are characterized by a smaller average body size of the fish sampled in the coastal waters due to the prevalence of the young specimens in this area.
... Bocaccio have a reported maximum estimated age of approximately 50 years (Love et al. 2002), and the species was validated to at least 37 years using bomb radiocarbon dating (Andrews et al. 2005, Piner et al. 2006. Canary rockfish have a reported maximum age of 84 years (Munk 2001), and the species was validated to at least 44 years with bomb radiocarbon dating and at least 54 years with lead-radium dating (Piner et al. 2005, Andrews et al. 2007). Yelloweye rockfish have one of the highest longevity estimates at 118 years (Munk 2001), with support from lead-radium dating to approximately 100 years (Andrews et al. 2002). ...
... Canary rockfish have a reported maximum age of 84 years (Munk 2001), and the species was validated to at least 44 years with bomb radiocarbon dating and at least 54 years with lead-radium dating (Piner et al. 2005, Andrews et al. 2007). Yelloweye rockfish have one of the highest longevity estimates at 118 years (Munk 2001), with support from lead-radium dating to approximately 100 years (Andrews et al. 2002). Given these maximum ages, and knowing the age at maturity for bocaccio, canary and yelloweye rockfishes (approximately 7, 8, and 19 years, respectively), and the number of productive years for the potential lifespan can be calculated. ...
Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the Abstract iii oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies since the first lead-radium dating study on fish in 1982. The activity of radium-226 measurements ranged over 3 orders of magnitude (<0.001 to >1.0 dpm·g-1). An analysis revealed ontogenetic differences in radium-226 uptake that may be attributed to changes in habitat or diet. Radiometric age from otolith core studies was used to describe a radium-226 uptake time-series for some species, which revealed interesting patterns over long periods. This synopsis provides information on the uptake of radium-226 to otoliths from an environmental perspective, which can be used as a basis for future studies.
... This exclusively freshwater species inhabits shallow (<4 m) warm-water lakes and pond-like areas of rivers, and is tolerant of eutrophication and high turbidity 1,2 . Shallow habitats are not typically associated with a long lifespan 7,8 . ...
... Measured Δ 14 C values were used to determine the validity of age estimates by comparing the purported year of formation (birth year), calculated from the collection year and estimated age relative to regional Δ 14 C references (Figs. 4,8,and 9). Temporal alignment of the measured Δ 14 C values from otolith material with regional Δ 14 C reference records from otoliths of other freshwater fishes provided an independent basis for determining fish age, and for evaluating our age reading protocol for Bigmouth Buffalo based on otolith annulus counts. ...
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-dollar industry in the past decade. All harvest is virtually unregulated and unstudied, and Bigmouth Buffalo are declining while little is known about their biology. Using thin-sectioned otoliths and bomb-radiocarbon dating, we find Bigmouth Buffalo can reach 112 years of age, more than quadrupling previous longevity estimates, making this the oldest known freshwater teleost (~12,000 species). We document numerous populations that are comprised largely (85–90%) of individuals over 80 years old, suggesting long-term recruitment failure since dam construction in the 1930s. Our findings indicate Bigmouth Buffalo require urgent attention, while other understudied fishes may be threatened by similar ecological neglect.
... -instantaneous natural mortality rates by age groups, taking the maximum recorded life span of Atka mackerel in the Bering Sea into account (15 full years [15]). ...
... However, the latter population has a higher rate of weight increase. The limit age for fish in the Kuril-Kamchatka population is 16+ years [6]; for Aleutian fish, according to data published in the literature [15], it is 15 years. This data, along with the information on maturation rate, constitutes the basis for calculating mortality rates by analytical methods. ...
The dynamics of the Atka mackerel stock in the Olyutorsky–Navarin area in 1994–2019 is inferred from bottom-trawl surveys, fishery statistics, open-access NOAA data, and the results of simulation by the method of virtual population analysis. After the period of low stock in the mid-1990s, the abundance of the Atka mackerel group in the area increased sharply to a maximum in 2006–2008, when the spawning biomass was estimated at approximately 9500 t and the fishery biomass at 14 000 t. In 2008, the stock showed a tendency to decrease; by 2013, the spawning stock decreased to 3600 t and the fishery stock to 5600 t; subsequently, there was a period of stabilization at a low level with a slight tendency to further reduction. One of the possible causes of the sharp increase in the Atka mackerel stock in the 2000s could be the increased transport of juveniles of strong year-classes from the main spawning grounds off the Aleutian Islands with their subsequent settlement on available parts of the shelf off Cape Olyutorsky. The development of the Atka mackerel fishery in the Olyutorsky–Navarin area in 1994–2019 had a pattern similar in general to the stock dynamics. Until 1995, no more than an average of 100 t were caught per year; in 2006–2010, the average annual catch increased to 790 t; in 2011–2015, it increased to 1150 t; and in 2016–2019, the catch again decreased to 950 t. Due to the emerging trend of a general reduction in the stock of the Aleutian population, this low level of catches in the Olyutorsky–Navarin area is expected to continue in the coming years.
... In the Ts'ishaa column sample assemblage, the increased recovery of herring and anchovy clearly demonstrates an increased abundance for these small fish taxa (<25cm, Hart 1973). However, it is difficult to know the size range of some of the other species found in the assemblage because many of these marine fish continue to grow throughout their often lengthy lifetimes (e.g., Munk 2001) and this makes singular estimates of body size a dubious proposition (Casteel 1976b:llg). As discussed previously, both rockfish and greenling represent significant proportions of the unit and column assemblages, but the abundance of rockfish is dramatically lower in the column assemblage whereas the abundance of greenling is incrementally larger in the column sample assemblage (Figure 8). ...
... Shaded vertical columns denote temporal periods. both are long-lived (Munk 2001), non-migratory taxa that inhabit high-relief rocky reef habitat (Murie et al., 1994) as surrounds Ts'ishaa and the Broken Group Islands (Tomascik and Holmes 2003). These qualities make these taxa vulnerable to overexploitation and are principal reasons for the current marine protected area status encompassing the Broken Group Islands (Deptartment of Fisheries and Oceans 2004b). ...
... Within our scan for positively selected genes we identified genes associated with longevity. Although the two species have similar lifespans, there are extensive differences between life spans across species within the genus [61], and genes associated with longevity were identified within our previous study [46]. The congener closely related to S. goodei is S. paucispinis [13], which can live to at least 46 years [61]. ...
... Although the two species have similar lifespans, there are extensive differences between life spans across species within the genus [61], and genes associated with longevity were identified within our previous study [46]. The congener closely related to S. goodei is S. paucispinis [13], which can live to at least 46 years [61]. By comparison, the nearest congener to S. saxicola is S. semicinctus, which can live up to 15 years [43]. ...
The genetic mechanisms of speciation and adaptation in the marine environment are not well understood. The rockfish genus Sebastes provides a unique model system for studying adaptive evolution because of the extensive diversity found within this group, which includes morphology, ecology, and a broad range of life spans. Examples of adaptive radiations within marine ecosystems are considered an anomaly due to the absence of geographical barriers and the presence of gene flow. Using marine rockfishes, we identified signatures of natural selection from transcriptomes developed from gonadal tissue of two rockfish species (Sebastes goodei and S. saxicola). We predicted orthologous transcript pairs, and estimated their distributions of nonsynonymous (Ka) and synonymous (Ks) substitution rates.
We identified 144 genes out of 1079 orthologous pairs under positive selection, of which 11 are functionally annotated to reproduction based on gene ontologies (GOs). One orthologous pair of the zona pellucida gene family, which is known for its role in the selection of sperm by oocytes, out of ten was identified to be evolving under positive selection. In addition to our results in the protein coding-regions of transcripts, we found substitution rates in 3' and 5' UTRs to be significantly lower than Ks substitution rates implying negative selection in these regions.
We were able to identify a series of candidate genes that are useful for the assessment of the critical genes that diverged and are responsible for the radiation within this genus. Genes associated with longevity hold potential for understanding the molecular mechanisms that have contributed to the radiation within this genus.
... Кроме того, в качестве исходной информации использованы: -среднемноголетние значения массы, доли половозрелых рыб и рыб промыслового размера по возрастам, рассчитанные по данным полных биологических анализов; -мгновенные коэффициенты естественной смертности по возрастным группам с учетом предельной наблюденной продолжительности жизни северного одноперого терпуга в Беринговом море (15 полных лет [Munk, 2001]). ...
... Рис. 12. Параметры, используемые при ретроспективной оценке биомассы северного одноперого терпуга модельными методами: а -масса рыб по возрастным группам; б -доля половозрелых рыб; в -доля рыб, достигших промыслового размера (более 32 см по АС, или более 30 см по AD); г -мгновенные коэффициенты естественной смертности; 1 -алеутская популяция; 2 -курило-камчатская популяция Fig. 12. Parameters used for retrospective estimation of the atka mackerel biomass by modeling: а -body weight, by age groups; б -portion of mature fish; в -portion of fish with commercial size (AC >32 cm or AD >30 cm); г -natural mortality rate; 1 -Aleutian population; 2 -Kuril-Kamchatka population Предельный возраст для рыб курило-камчатской популяции составляет 16+ лет [Золотов и др., 2015], для алеутской по литературным данным [Munk, 2001] -15 лет. Эти данные наряду с информацией по скорости созревания являются основой для расчетов коэффициентов смертности аналитическими методами, и, как можно видеть, в среднем оценки мгновенных коэффициентов естественной смертности по возрастным группам методом П.В. ...
Atka mackerel Pleurogrammus monopterygius is one of the mass species of fam. Hexagrammidae that inhabits the boreal and subarctic waters of the North Pacific and forms two large populations in its western and eastern parts. Reproductive range of the eastern, Aleutian population extends from the Gulf of Alaska, along Aleutian Islands to Commander Islands, with the main spawning grounds at the Aleutians and in the southeastern Bering Sea. From these areas, the fish at early stages of ontogenesis spread widely in system of the Bering Sea currents to the western-southwestern Bering Sea, where the atka mackerel aggregations are formed on the external shelf at prominent capes, as Cape Olyutorsky. Dynamics of the atka mackerel stock in the Olyutorsky-Navarinsky area in 1994–2019 is presented on the base of bottom trawl surveys, fishery statistics, and open NOAA data. After the period of low stock in the middle 1990s, the atka mackerel abundance increased sharply to the maximum in 2006–2008, when the spawning stock in this area was about 9.5 . 103 t and the commercial stock about 14.0 . 10 ³ t. Since that time, trend to decreasing is observed, with the spawning stock 3.6 . 10 ³ t and the commercial stock 5.6 . 10 ³ t in 2013, and recent stabilization at the low level with slight decline continuing. A possible reason of the sharp increase in 2000s could be the intensive transport of the atka mackerel juveniles from the main spawning grounds at Aleutian Islands to the area at Cape Olyutorsky. The catches of atka mackerel in the Olyutorsky-Navarinsky area in 1994–2018 corresponded well with its stock dynamics.
... These characteristics allow this group to recover their populations from fishing extraction rapidly; however, it is not an intrinsic characteristic of all bony fish species, and proper management tools are necessary to maintain healthy populations. For example, scorpionfishes of the Sebastes genus resulted with moderate to low productivity due to their reproductive strategy and great longevity (Echeverria, 1987;Reilly et al., 1994;Cailliet et al., 2001;Munk, 2001;Love, 2012;Berkel and Cacan, 2021). Also, we identified several species (e.g., Hypsopsetta guttulata, Kyphosus azureus, Mycteroperca jordani, Sebastes atrovirens, S. chrysomelas, S. miniatus, S. rastrelliger, S. rosenblatti, S. rufus, S. semicinctus, S. serranoides, S. serriceps, S. simulator, S. umbrosus, and Semicossyphus pulcher) with limited geographic distribution, increasing their encounterability with the fishing activities (Eschmeyer et al., 1983;Williams and Ralston, 2002;Fricke et al., 2021). ...
The main key drivers of vulnerability for marine species are anthropogenic stressors, ranging from pollution and fishing to climate change. The widely documented impacts of fishing activities on marine species, the growing concern about the population status of many marine species, and the increase in per capita consumption of marine products worldwide have led to the development of environmentally responsible fishing standards and initiatives to inform consumers about the health status of the species. In Mexico, fishing is a vital source of jobs and food security for many coastal communities, but the population status of many species of commercial importance has not been evaluated. Management efforts and fisheries certification procedures and standards to achieve the sustainability of many Mexican fisheries are hindered by a lack of biological and fishery data for many species. In this study, a risk assessment methodology for data-limited fisheries, a Productivity, and Susceptibility Analysis was used to estimate the relative vulnerability of marine invertebrates and fishes commercially important in Mexico to fishing. Ninety-eight invertebrates, 66 elasmobranchs, and 367 bony fish were analyzed. The vulnerability among the 531 evaluated species is high for 115 (22%), moderate for 113 (21%), and low for 303 (57%). The most vulnerable species are the Mexican geoduck (Panopea globosa) and the Black Sea Cucumber (Holothuria atra) for invertebrates, the Spiny butterfly ray (Gymnura altavela) among elasmobranches, and the Black-and-yellow rockfish (Sebastes chrysomelas) for bony fishes. This study provides a first screening of the many species potentially affected by fisheries, prioritizes marine species for future research and management efforts, identifies the main data gaps, and sets the baseline for future research efforts and management. Furthermore, the results could improve market-based approaches like eco-labeling initiatives and the Responsible Seafood
... The MLS values of these species vary from 61 yrs for painted turtle (Congdon et al., 2003) to 507 yrs for ocean quahog (Butler et al., 2013). One of the putative causes of this longevity is the constant growth of individuals, such as the rougheye rockfish (Munk, 2001), long-living turtles, and the ocean quahog (Zyuganov, 2008). This negligible senescence may be determined by high activity of intracellular antioxidant agents, as in the ocean quahog, or efficient repair, as in the red sea urchin (Korotkova, 1997). ...
Different types of senescence and major theories of aging are reviewed, and mechanisms of this
complex biological phenomenon are discussed. Emphasis is placed on changes in the nervous systems of
mammals and humans with age. Experimental animal models for studying aging and modern approaches to
the correction of age-related deterioration are considered. Chemicals and other factors that may alleviate age-related
disorders and slow down senescence are critically reviewed.
... This species appears to be one of the longest lived Sebastes species. The maximum age recorded in British Columbia (BC) is 147; whereas the maximum age reported anywhere is 205 from SE Alaska (Munk 2001). Adults reach a maximum length of 90 cm. ...
This paper reviews the current data on the biology, distribution, and abundance trends for rougheye rockfish Sebastes aleutianus. The information contained herein is primarily for use in a COSEWIC status report on this species. It is not meant to be a comprehensive stock assessment. This species has a mean weight of 1.585 kg/fish. Allometric growth shows no difference between the sexes; and males are generally no bigger than females of equal age. With an estimated age-of-50%-maturity at 20.3 years, and an assumed natural mortality rate of 0.035, generation time is roughly 48 years. Posterior model estimates of total mortality rate Z for the survey year 1997 range from 0.034 to 0.063, with a mean of 0.048. Commercial age proportions in 1996 yield essentially the same estimate of Z, ranging from 0.028 to 0.061 with a mean of 0.045. In 2003, older age classes appear truncated and younger fish predominate. The posterior distribution of Z ranges from 0.060 to 0.113 with a mean of 0.091. According to commercial trawl records, rougheye rockfish prefer depths between 171 m and 658 m. Using this preference, a bathymetric analysis estimates the potential extent of occurrence at 37,145 km2 and the area of occupancy at 18,530 km2. However, based on trawl and logline observations, the area of occupancy could easily equal 35,100 km2. Within its habitat, the two dominant concurrent species are arrowtooth flounder Atheresthes stomias and Pacific ocean perch Sebastes alutus. Total removal of rougheye rockfish from BC coastal waters by the commercial fleet from 1971 to 2005 equals approximately 16 million fish. Survey indices of abundance are currently not useful for assessing rougheye rockfish population trends. The Hecate Strait assemblage, WCVI shrimp trawl, and NMFS triennial surveys are too shallow. The QCS shrimp survey, while showing an increasing abundance trend, is too limited in areal extent. The QCS synoptic survey, which will become the most reliable, currently has too few data points. The commercial trawl CPUE indices show a slightly increasing trend in 3CD and essentially flat trends in 5AB and 5E.
URL: http://www.dfo-mpo.gc.ca/csas-sccs/publications/resdocs-docrech/2005/2005_096-eng.htm
... Maximum age from 14 C indicates that the Arctic ICES, 2011), Pacific (ICES, 2011 and Northwest Atlantic stocks have a lifespan of about 35 years and, since the bomb radiocarbon sample here included fish lengths close to the known maximum species' size, it seems likely that this approximates the actual longevity of the species. Greenland Halibut is considered a moderately lived flatfish; other flatfish, such as Atlantic Halibut (40-50 years; Armsworthy and Campana, 2010), Pacific Halibut (55 years; Piner and Wischniowski, 2004), and Dover Sole (Microstomus pacificus, 60 years; Munk, 2001), are considered long lived; others less so, but with longevities greater than age estimates from traditional whole otoliths would have indicated (Yellowtail Flounder (25 years;Dwyer et al., 2003) and Starry Flounder (Platichthys stellatus, 24 years; Campana, 1984). ...
... The speciose genus Sebastes supports commercial fisheries in both the Pacific and Atlantic oceans, where they are known as rockfish and redfish respectively. Many of the species are deepwater species and some are now known to reach ages of over 75 (in the Atlantic) and 200 years (in the Pacific) (Campana et al. 1990;Munk 2001), making them less capable of supporting an intensive fishery. Indeed, overexploitation leading to fisheries closures has already occurred in some areas (Department of SPECIAL ISSUE Fisheries and Oceans Canada, DFO 2012). ...
Many past attempts to age deep-water redfish (Sebastes mentella) and Acadian redfish (S. fasciatus) in the northwest Atlantic have been stymied by inappropriate ageing methods, the absence of age validation and the failure to differentiate among species. Herein we report substantial improvements in methods for ageing Sebastes spp. by linking the established 'crack and burn' method to modern sectioning and image-enhancement protocols. Bomb radiocarbon assays of the otolith core and monitoring of year-class progression confirmed the accuracy of the resulting age determinations to an age of 46 years. The use of microsatellite DNA to confirm species identity eliminated past confusion caused by species mixtures. Age determinations of 1252 redfish from the eastern coast of Canada demonstrated the presence of significant differences in growth rate and longevity both between the two redfish species and among populations and stocks, with a maximum observed longevity of 70 years. Even within species and stocks, an individual fish with a fork length of 38 cm could be anywhere between 15 and 50 years of age, highlighting a near cessation of somatic growth after sexual maturation. In keeping with other deep-water species, sustainable management will require more attention to the low productivity expected of redfish stocks, rather than the high initial biomass that can support short-term but high catch rates.
... The speciose genus Sebastes supports commercial fisheries in both the Pacific and Atlantic oceans, where they are known as rockfish and redfish respectively. Many of the species are deepwater species and some are now known to reach ages of over 75 (in the Atlantic) and 200 years (in the Pacific) (Campana et al. 1990; Munk 2001), making them less capable of supporting an intensive fishery. Indeed, overexploitation leading to fisheries closures has already occurred in some areas (Department of ...
Aquatic ecosystems are under threat from multiple stressors, which vary in distribution and intensity across temporal and spatial scales. Monitoring and assessment of these ecosystems have historically focussed on collection of physical and chemical information and increasingly include associated observations on biological condition. However, ecosystem assessment is often lacking because the scale and quality of biological observations frequently fail to match those available from physical and chemical measurements. The advent of high-performance computing, coupled with new earth observation platforms, has accelerated the adoption of molecular and remote sensing tools in ecosystem assessment. To assess how emerging science and tools can be applied to study multiple stressors on a large (ecosystem) scale and to facilitate greater integration of approaches among different scientific disciplines, a workshop was held on 10–12 September 2014 at the Sydney Institute of Marine Sciences, Australia. Here we introduce a conceptual framework for assessing multiple stressors across ecosystems using emerging sources of big data and critique a range of available big-data types that could support models for multiple stressors. We define big data as any set or series of data, which is either so large or complex, it becomes difficult to analyse using traditional data analysis methods.
... Sablefish (Anoplopoma fimbria), which is also known as Alaskan Black Cod and butterfish, is a native marine finfish species that has an established fishery. The age structure (lifespan >90 years [Munk, 2001]) of the wild sablefish population brings into question the long-term viability and sustainability of the fishery, given the increasing demand for this very high valued species, and has thus suggested a role for aquaculture. Following years of research on hatchery methods and juvenile rearing, this species is now under early stage commercial production with four licensed and operating farms on the coast. ...
This is a workshop proceedings, edited by Harvey, Soto, Carolsfeld, Beveridge and Bartley and published by the FAO.
The workshop identified three main strategies for aquaculture diversification:
1) increase the number of species being farmed; 2) increase the evenness of farmed
species; and 3) increase the diversity within currently farmed species by developing
new strains. The workshop identified some primary drivers of diversification: market
demand (including export opportunities), funding opportunities, competition and
climate change, as well as other environmental and social factors.
Diversification of species and culture systems and a more even distribution of
production could provide resilience in the face of a changing climate and other external
drivers and add economic, social and ecological insurance to aquaculture systems.
However, diversification is not without risks and may not always be a viable means to
increase fish production. In addition to purely economic costs there will be associated
development costs, including evaluation and mitigation of environmental and social
impacts and establishment of species-specific biosecurity frameworks. The workshop
identified general principles that can help guide diversification in aquaculture.
... years of age (McDermott, 1994). Rougheye rockfish have been estimated to attain ages in excess of 200 years and shortraker rockfish in excess of 150 years (Munk, 2001). These two species are currently managed together as the "shortraker-rougheye" assemblage within waters managed under a North Pacific Fishery Management Council (NPFMC) fishery management plan. ...
Rougheye rockfish (Sebastes aleutianus) and shortraker rockfish (Sebastes borealis) were collected from the Washington coast, the Gulf of Alaska, the southern Bering Sea, and the eastern Kamchatka coast of Russia (areas encompassing most of their geographic distribution) for population genetic analyses. Using starch gel electrophoresis, we analyzed 1027 rougheye rockfish and 615 shortraker rockfish for variation at 29 protein-coding loci. No genetic heterogeneity was found among shortraker rockfish throughout the sampled regions, although shortraker in the Aleutian Islands region, captured at deeper depths, were found to be significantly smaller in size than the shortraker caught in shallower waters from Southeast Alaska. Genetic analysis of the rougheye rockfish revealed two evolutionary lineages that exist in sympatry with little or no gene flow between them. When analyzed as two distinct species, neither lineage exhibited heterogeneity among regions. Sebastes aleutianus seems to inhabit waters throughout the Gulf of Alaska and more southern waters, whereas S. sp. cf. aleutianus inhabits waters throughout the Gulf of Alaska, Aleutian Islands, and Asia. The distribution of the two rougheye rockfish lineages may be related to depth where they are sympatric. The paler color morph, S. aleutianus, is found more abundantly in shallower waters and the darker color morph, Sebastes sp. cf. aleutianus, inhabits deeper waters. Sebastes sp. cf. aleutianus, also exhibited a significantly higher prevalence of two parasites, N. robusta and T. trituba, than did Sebastes aleutianus, in the 2001 samples, indicating a possible difference in habitat and (or) resource use between the two lineages.
... This will lead to a lower precision between age readers. Munk (2001) aged shortraker rockfish up to 157 years, while the oldest age we generated using strategy 3 was 102 years. A future goal will be to work with other age readers to establish a set of ageing criteria that will produce ages with reasonable precision. ...
... The increasing focus on salmon use in Gwaii Haanas may also have been driven by declining returns on previously important resources. This is particularly true for an economy initially focused on rockfish (Orchard 2009;Orchard and Clark 2005), which are nonmigratory fish which commonly reach ages of fifty to two hundred years (Love , Yoklavich, and Thorsteinson 2002;Munk 2001). These life-history traits make rockfish highly susceptible to overexploitation (Berkeley et al. 2004), andMcKechnie (2007) and McMillan et al. (2008) have documented prehistoric overharvesting and subsequent depression of local rockfish populations in Barkley Sound on western Vancouver Island. ...
... Although rougheye and blackspotted rockfish have been reported to be greater than 200 years old (Munk 2001), the highest age collected over these survey years was 132 (AFSC 2006). The average age ranged from 15 to 23 over all survey years available. ...
Executive Summary We present various types of information on Gulf of Alaska (GOA) rougheye and blackspotted rockfish to evaluate potential stock structure within this species complex. Recently, the presence of two species, rougheye rockfish (Sebastes aleutianus) and blackspotted rockfish (S. melanostictus), was formally verified in what was once considered a single variable species with light and dark color morphs. Since 2007, assessment authors have been requested to develop a rationale for decisions regarding mixed stock species groups with attention to overfishing the weaker stock. Currently, there is no information on whether the two species have significantly different life history traits (e.g. age of maturity, growth). An attempt to separate data by species has occurred for several years on the Alaska Fisheries Science Center (AFSC) bottom trawl survey. However, several special projects with include genetic identification have shown high rates of misidentification in the field. Scientists and observers are currently evaluating new techniques to determine whether rapid and accurate field identification can occur. Until observers and survey biologists can reliably identify both species, we must continue to manage rougheye and blackspotted as a complex. We, therefore, present the available stock structure data for the two species as a complex and refer to this as the rougheye/blackspotted rockfish complex or RE/BS rockfish. We follow the stock structure template recommended by the Stock Structure Working Group (SSWG) and elaborate on each category within this framework. Both non-genetic and genetic information are consistent with population structure by large management areas of eastern, central, and western GOA defined by fishery and survey sampling. This is evident in the non-genetic data as opposite trajectories for population trends by area, significantly different age, length, and growth parameters by area, and significant differences in parasite prevalence and intensity by area. Genetic studies have generally been focused on the speciation of the RE/BS complex; however, consistencies between the two species also suggest population structure by management area. Tests of homogeneity and adjacency show genetic structure consistent with a neighborhood model of dispersion. Dispersal distance for blackspotted rockfish in the GOA was consistent with management areas while rougheye rockfish in the northeastern GOA may exhibit finer scale population structure. Currently, GOA RE/BS rockfish is managed as a Tier 3a species with area-specific Acceptable Biological Catch (ABC) and gulf-wide Overfishing Level (OFL). Given the multiple layers of precaution instituted with relatively low Maximum Retained Allowance (MRA) percentages, a bycatch only fishery status, and the on average low area-specific harvest rates, we continue to recommend the current management specifications for RE/BS rockfish. September 2010 Plan Team Draft Rougheye and blackspotted rockfish stock structure This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by the National Marine Fisheries Service and should not be construed to represent any agency determination or policy.
... Note that for 1993-2004, information on catch by gear is only available for the shortraker/rougheye category and not for shortraker alone. Shortraker/Rougheye Rockfish Gear 1993199419961997199819992001 Nearly all the longline catch of shortraker rockfish appears to have come as "true" incidental catch in the sablefish or halibut longline fisheries. In rockfish trawl fisheries, however, some of the shortraker is taken by actual targeting that some fishermen call "topping off" (Ackley and Heifetz 2001). ...
... We now have nine years of survey age compositions, with sample size total of 4,351 ages. Although rougheye and blackspotted rockfish have been reported to be greater than 200 years old (Munk 2001), the highest age collected over these survey years was 132 (AFSC 2006). The average age ranged from 15 to 23 over all survey years available (Table 13-6). ...
Executive Summary Rockfish are assessed on a biennial stock assessment schedule to coincide with new survey data. We use a separable age-structured model as the primary assessment tool for Gulf of Alaska rougheye and blackspotted rockfish. The model consists of an assessment, which uses survey and fishery data to generate a historical time series of population estimates, and a projection which uses results from the assessment model to predict future population estimates and recommended harvest levels. The model was constructed with AD Model Builder software and allows for size composition data that is adaptable to several rockfish species. The data sets used in this assessment include total catch biomass, fishery size compositions, trawl and longline survey biomass estimates, trawl survey age compositions, and longline survey size compositions. Orr and Hawkins (2008) formally verified the presence of two species, rougheye rockfish (Sebastes aleutianus) and blackspotted rockfish (S. melanostictus), in what was once considered a single variable species with light and dark color morphs. Hereafter we refer to these two species together as the rougheye/blackspotted rockfish complex or RE/BS rockfish. Changes in the input data: New data added to this model were the updated estimates of 2007-2009 fishery catch, 2004 and 2006 fishery ages, 2007 fishery length compositions, 2009 trawl survey biomass estimate, 1987 and 2007 trawl survey age compositions, 2008-2009 longline survey relative population weights, and 2008-2009 longline survey size compositions. Changes in the assessment methodology: The assessment methodology is very similar to the 2007 model which utilized the age error structure based on rougheye/blackspotted rockfish and the more accurate estimates of historical rougheye/blackspotted catch for 1993-2004. Additionally, we decreased the CV on the catch time series and utilized the catch reliability penalty in 1993. A CV of approximately 30% is implemented for the earlier part of the catch time series (1977-1992) where catches are not as well known, while a CV of 5% was used for the rest of the time series. As determined in the 2007 SAFE appendix analysis, the increased weight on the catch time series allows for increased robustness of the model to weighting sensitivity.
... New maximum age information includes 116 years for Gulf of Alaska shortraker, 47 for Gulf of Alaska harlequin, 36 for Gulf of Alaska redstripe, and 82 for British Columbia silvergray. One researcher has reported an extremely old maximum age for shortraker rockfish in the Gulf of Alaska of 157 years (Munk 2001). If true, this would make shortraker rockfish one of the longest-lived of all fishes. ...
Major new information in this assessment includes biomass estimates from the 2007 trawl survey, the first-ever survey age results in Alaska for shortraker, sharpchin, redstripe, harlequin, and silvergray rockfish, and new information on age-and-growth and natural mortality rates for several "other slope rockfish" species. Assessment methodology in this report is generally similar to that used in past assessments for shortraker rockfish and "other slope rockfish", but changes were made to the way that exploitable biomass is calculated and to the natural mortality rate used for silvergray rockfish. Previously, exploitable biomass for shortraker rockfish and "other slope rockfish" was estimated by the unweighted average biomass of the most recent three Gulf of Alaska trawl surveys, excluding the biomass in the 1-100 m depth stratum. The removal of the 1-100 m stratum from the estimate was a holdover from many years ago when the assessment included Pacific ocean perch; the rationale was that small-sized Pacific ocean perch predominated in this stratum, and these fish should be considered unexploitable. However, an analysis presented in the current assessment shows that the biomass of shortraker rockfish and "other slope rockfish" in this stratum is negligible; hence, the exclusion of the 1-100 m stratum from the exploitable biomass computations for these groups appears unnecessary. Including this shallow stratum, and averaging the biomass estimates in the last three Gulf of Alaska trawl surveys (2003, 2005, and 2007), results in an exploitable biomass of 39,905 mt for shortraker rockfish and 90,283 mt for "other slope rockfish". Shortraker rockfish and the various "other slope rockfish" species have always been classified into tier 5 in the NPFMC's ABC and OFL definitions, except for sharpchin rockfish which have been in tier 4 for several years. Now that age results are available for shortraker, redstripe, harlequin, and silvergray rockfish, these species could potentially be moved into tier 4 also. However, for the present assessment it was decided to keep these species in tier 5 until better verification of the new ages is available, along with additional age results. The tier 5 definitions state that F ABC #0.75M. Applying this definition to the exploitable biomass of shortraker rockfish results in a recommended ABC of 898 mt in 2008. For "other slope rockfish", applying an F ABC #F 40% rate to the exploitable biomass of sharpchin rockfish (tier 4) and an F ABC #0.75M rate to that of the other species (tier 5) results in ABC's of 836 mt and 3,461 mt, respectively, or a combined recommended ABC of 4,297 mt for the "other slope rockfish" management group in 2008.
... Additionally, quillback are long-lived (up to 90 years, Munk 2001) and late to mature (between the ages of 5 and 22 years, Love et al. 2002), which makes them slower to rebound from population declines than fish that have faster growth rates and earlier onset of reproduction. ...
Multiple paternity, also termed polyandry, is a reproductive strategy that can increase the genetic variation within a brood to help preserve diversity within a population. A paternity analysis using multilocus microsatellites revealed that 8 of 25 (32%) quillback rockfish (Sebastes maliger) females mated with more than one male. Of the eight broods sired by multiple males, three were sired by two males and five were sired by three males. Polyandry is likely an important consideration when managing rockfish stocks for genetic diversity and productivity. The probability of polyandry increased with increasing weight and condition factor of the female, but not with increasing age or length. These results suggest polyandry is a common mating strategy in quillback rockfish in Alaska and may be related to female size.
... Historical classical anecdotes (Plinio the elder, Seneca; Decimo Giunio Giovenale, Luciano di Samosata) and more recent reports (Hederström, 1959) indicate that marine species are able to reach huge dimensions and live astonishing life span. This slow and longevity scenario is also supported by the reconstruction of features of past unexploited stock (Saenz-Arroyo et al., 2006;Vogt, 2012) and some direct (Bennett et al., 1982;Campana et al., 1990) and indirect (Beamish & McFarlane, 2000) age estimation, resulting in ages up 205 y in Sebastes (Munk, 2001) and 98 y in the molluscs Panope (Bradbury & Tagart, 2000). ...
... We now have survey age compositions corresponding to all survey biomass estimates used in the model except 2011. Although rougheye and blackspotted rockfish have been reported to be greater than 200 years old (Munk 2001), the highest age collected over these survey years was 135 (AFSC 2010). The average age ranged from 15 to 23 over all survey years available (Table 13-11). ...
Executive Summary Rockfish are assessed on a biennial stock assessment schedule to coincide with the availability of new survey data. We use a separable age-structured model as the primary assessment tool for Gulf of Alaska rougheye and blackspotted rockfish (RE/BS complex). This consists of an assessment model, which uses survey and fishery data to generate a historical time series of population estimates, and a projection model, which uses result from the assessment model to predict future population estimates and recommended harvest levels. For Gulf of Alaska rockfish in alternate (even) years we present an executive summary to recommend harvest levels for the next (odd) year. For this on-cycle year, we update the 2009 assessment model estimates with new data collected since the last full assessment. The data sets used in this assessment include total catch biomass, fishery age and size compositions, trawl and longline survey biomass estimates, trawl survey age compositions, and longline survey size compositions. Summary of Changes in Assessment Inputs Changes in the input data: New data added to this model include a revised catch estimate for 2010, an estimated catch for 2011, fishery ages for 1990 and 2008, trawl survey biomass estimate for 2011, trawl survey age compositions for 2009, longline survey relative population weights for 2010-2011, and longline survey size compositions for 2010-2011.
... Concordance with the results of Hannah et al. 5 is unsurprising because their age estimates compose a portion (~10%) of our data for deacon rockfish. However, McClure (1982) reported much larger sizes at age, possibly as a result of the use of surface reads instead of the break-and-burn technique (Laidig et al., 2003; this study), as surface reads may underestimate age in rockfish species (Chilton and Beamish, 1982;Munk, 2001). ...
... The maximum age of walleye pollock is estimated to be from 15 years [63] to 28 years [65]. At the same time, the catches in the Bering Sea are dominated by fish aged from 2+ to 5+ years, which account for about 90% in the western Bering Sea and more than half of the catches in the eastern Bering Sea [66]. ...
The first records of walleye pollock Gadus chalcogrammus Pallas, 1814 in the seas of the Siberian Arctic (the Laptev Sea, the Kara Sea, the southeastern Barents Sea), are documented. Information about the external morphology (morphometric and meristic characters), photos of sagittal otoliths and fish, and data on the sequences of the CO1 mtDNA gene are presented. The results of a comparative analysis indicate that walleye pollock caught in the Siberian Arctic do not differ in principle from North Pacific and North Atlantic individuals. Previous conclusions about the con-specificity of the walleye and Norwegian pollock Theragra finnmarchica are confirmed. New captures of walleye pollock in the Siberian Arctic allow us to formulate a hypothesis about its continuous species' range from the coasts of Norway in the North Atlantic to the coasts of Korea, Japan, and California in the North Pacific. The few records of walleye pollock in the North Atlantic originate from the North Pacific due to the transport of early pelagic juveniles to the Arctic by currents through the Bering Strait and further active westward migrations of individuals which have switched to the bentho-pelagic mode of life.
... In fact, the otolith mass-age relationship developed by Sanchez et al. (2019) lead to an age-96 estimate for the individual (2.51-g otolith), again similar to results from H. octofasciatus and H. quernus in the Hawaiian Islands where otolith-mass relationships were used to estimate ages of prebomb fish (Andrews et al., 2011(Andrews et al., , 2019. Furthermore, longevity approaching 100 years is not uncommon for deepwater species (Cailliet et al., 2001;Munk, 2001) and longevity of 80 or more years has been reported for other species in the deepwater grouper complex in the GoM using bomb radiocarbon validation techniques (Cook et al., 2009;Andrews et al., 2013;Sanchez et al., 2019). Such an increase in longevity would substantially decrease current SEDAR (Southeast, Data, and Assessment Review) natural mortality estimates for the species, which use the Hewitt and Hoenig (2005) estimate, from 0.10 y − 1 (SEDAR, 2004) to 0.05 y − 1 (our data) and emphasizes the importance of validating age estimates for the development ...
Warsaw grouper (Hyporthodus nigritus) in the Gulf of Mexico (GoM) are currently managed as a single-stock; however, patchy distribution of suitable habitat may promote the development of discrete populations with different life history characteristics thereby complicating conservation policy. We estimated ages and age-length relationships of Warsaw grouper from different geographic regions in the GoM and applied von Bertalanffy growth functions (VBGF) to estimate growth parameters (L∞ and K) for each region. Otolith-based ages ranged from 1 to 91 years and estimated L∞ and growth coefficient (K) derived from the VBGF for all Warsaw grouper combined were 188.8 cm total length (TL) and 0.034 respectively. Region-specific growth parameters were similar for most of the GoM when VBGFs were limited to Warsaw grouper < 25 years old, though growth was considerably faster from the southeast GoM. When our age-length key was applied to fisheries-dependent length data from the GoM in 2001–2006 and 2011–2016, this fishery was comprised primarily of Warsaw grouper < age-1, but the mean age increased between catches from 2001 to 2006 (4.7 ± 8.3) and 2011–2016 (7.6 ± 6.4). Instantaneous mortality rates (Z) based on the decline of log abundance on age indicated relatively low Z rates across the four regions (range: 0.09−0.18), with a significantly higher mortality rate in the western GoM (0.17) than the eastern GoM (0.08). In this study we also observed a greater longevity (91 years) for the species than previously documented, greater than double the longevity used to develop current management policy.
... Вид обладает значительной продолжительностью жизни. По данным отдельных исследователей предельный возраст может достигать 94 лет [Munk, 2001], а валидность определения возраста особей угольной рыбы возрастом до 34 лет, постоянно присутствующих в промысловых и научных уловах, подтверждена радиокарбоновым методом и с помощью маркирования окситетрациклином . ...
Sablefish is an endemic species of the North Pacific. Its range extends from California Peninsula, along the Pacific coast of the US and Canada to Aleutian Islands and further, along the Pacific coast of Kamchatka and the Kuriles to the central part of Honshu Island. They dwell also in the Bering Sea and southeastern Okhotsk Sea. Sablefish are the most abundant in the southeastern Bering Sea and in the Gulf of Alaska, that is conditioned by favorable conditions for their larvae and juveniles. In the Asian part of the range, the environments are generally more severe, and reproduction of sablefish is rather risky. Following to the results of modern genetic studies, the sablefish stocks are distinguished by high genetic homogeneity that suggests a common population with the main spawning grounds in the southeastern Bering Sea, at the Pacific coasts of Aleutian Islands, in the Gulf of Alaska, and at the coasts of British Columbia, Washington, Oregon and California. Dynamics of the sablefish biomass is considered on the data of bottom and midwater trawl surveys conducted by TINRO in 2003–2020, fishery statistics, and accessible data of NOAA (USA). Sharp increasing of the biomass and annual catches is noted both in the eastern and western Bering Sea in the last few years because of appearance of several strong year-classes. Western Bering Sea stock depends on migration of recruits from the common spawning grounds in the southeastern Bering Sea. For the western Bering Sea, two main ways of such migration are possible: i) active migration of juveniles with benthic habitat; and ii) passive transfer of pelagic larvae and early juveniles across the Bering Sea through the system of surface currents. The latter mechanism supports the sablefish recruitment in the bays of the western Bering Sea and, to a lesser extent, at the eastern coast of Kamchatka. Sablefish in the West Bering Sea fishery zone were caught in 2010–2020 mostly as by-catch for trawling and longline fishery (93 %), other 7 % were landed by specialized longline fishery. The basic points for managing the sablefish fishery in the West Bering Sea zone are defined. About 400 t of sablefish is permissible to catch annually in the West Bering Sea fishery zone in conditions of modern high stock of this species. This value includes 100–120 t that will inevitably be caught as by-catch and the rest of 280–300 t is a foreseeable resource for organization of specialized fishery.
... Species identification of fish was performed using the Chereshnev and coauthors atlas [18] and the Fedorov and coauthors catalog [21]. Common names of fish are taken from the literature [2,12,17,22]. During biological analysis, the length of fish was measured from the beginning of the snout to the end of the middle rays of the caudal fin with an accuracy of 1 mm. ...
... In general, mesopelagic fishes are short-lived relative to many coastal and deep-sea Growth and reproduction in mesopelagic fishes benthic species (e.g. Tracey and Horn, 1999;Munk, 2001). However, there is some variation, ranging from those that only live one or 2 years (e.g. ...
The mesopelagic zone covers a vast expanse of the World's oceans and contains some of the most abundant vertebrates on the planet. This mid-water region is central to the transfer of energy and carbon between the atmosphere and the deep, yet there are large knowledge gaps in our understanding of the life history of its animals. Here we synthesize the current state of knowledge of research on age, growth, and reproduction of mesopelagic fishes, the basic biological information fundamental to understanding the population dynamics of species in this ecosystem. Collectively, two-thirds of life history research on mesopelagic fishes has been undertaken on myctophids, yet many other abundant and important groups are lacking research. There are generally hotspots of mesopelagic fish research mostly centred in the northern hemisphere, with little to no coverage in the Indo-Pacific region nor the poles. Furthermore, the effects of some anthropogenic stressors-chiefly climate change and resource extraction-on the life history of the animals in this zone is uncertain and needs to be considered. Knowledge of growth and reproduction are key traits required for a holistic assessment and understanding of this ecosystem, and hopefully this synthesis will provide a springboard for greater focus in this area.
... These anecdotes maybe are only legends, but this approach might be dangerous. Huge and very old specimens at sea has been thereafter supported by many Authors since the 267 years old pike reported by Hederstrom in 1759 (Anon., 1959) to the more modern publications suggesting life span often longer than 100 years and more (Bennett et al., 1982;Woodhead, 1998;Bradbury & Tagart, 2000;Carey & Judge, 2000;Munk, 2001;Buston & Garcia, 2007). ...
Mediterranean trawl fisheries traditionally begin to catch fish and shellfish recruits at a very precocious size /age, when the instantaneous rate of natural mortality (M) is expected to be quite higher than the corresponding mortality suffered by juveniles and adults. For these reasons, different methods to get M at age estimations were published in the last decades in fisheries. In particular, within the Mediterranean assessments, the “reciprocal inverse exponential declining function” (Abella et al., 1998; Caddy & Abella, 1999; A&C) and the “bathtub function or U-shaped curve” (Chen & Watanabe, 1989; C&W) were implemented. These methods are based on different assumptions and theories and have different management implications. For example, A&C does not take into consideration the possibility of increasing M with senescence (i.e. the pristine unexploited life span, Bios zoès, is almost infinite). On the contrary, C&Wforesees a dramatic increase of M towards the end of the unexploited life span (i.e. mortality tends to infinite after a determinate age). A&C requires six parameters, whereas only two parameters are necessary in C&W. As regards the management implications, adopting A&C would imply that the higher the reduction in fishing mortality (F) the higher the gain in stock size at sea expected; on the contrary, C&W foresees a decline of the stock after an initial increase due to the raise in M when the ageing specimens begin to suffer senescence. In the present note, the two approaches were compared and integrated in order to give a standard and objective tool covering recruits/juvenile, adult and senescent (if any) life history stages of Mediterranean groundfish (demersal) exploited stock. Parameters gathered from the reports produced by the Scientific, Technical and Economic Committee for Fisheries (STECF) were employed to illustrate the proposed method. C&W yields systematically higher M than A&C. A&C applications may result in too pessimistic (current status) and too optimistic (long term gains) than C&W independently from the eventual senescence incidence. The proposed standard methodology consists in using A&C for estimating current M in the Mediterranean groundfish stock, but adopting C&W for the projections since the latter are assumed more related to the M figures operating during the developing stages of the Mediterranean fisheries.
... Unfortunately, lack of species-specific information and an increase in fishing effort within this region is a cause of concern for fishery management (Jabado et al., 2017). Limited speciesspecific reporting combined with unregulated fishing has led to the depletion of many chondrichthyan fishes throughout the worlds' oceans (Dulvy and Reynolds, 2002;Sulikowski et al., 2007) and continues to hamper the progress of management plans (Hoff and Musick, 1990;Leaman, 1991;Munk, 2001). ...
A single specimen of a gravid female of the stripenose guitarfish, Acroteriobatus variegatus was landed as by-catch by a tuna hook and line at Sakthikulangara, Kerala from a depth of 110-130 m. The species is categorized as 'critically endangered' by IUCN. The morphometric characteristics of A. variegatus are described for the first time since its original description by Nair and Lal Mohan (1973) from Gulf of Mannar. The present study provides preliminary insights into its reproductive biology. The mode of reproduction in A. variegatus is aplacental yolk sac viviparity with low uterine fecundity.
... Concordance with the results of Hannah et al. 5 is unsurprising because their age estimates compose a portion (~10%) of our data for deacon rockfish. However, McClure (1982) reported much larger sizes at age, possibly as a result of the use of surface reads instead of the break-and-burn technique (Laidig et al., 2003; this study), as surface reads may underestimate age in rockfish species (Chilton and Beamish, 1982;Munk, 2001). ...
To better inform stock assessment and management decisions, we used multiple approaches for esti-mating and comparing species- specific characteristics of the spatiotemporal composition of catch and life history traits of blue rockfish (Sebastes mystinus) and deacon rockfish (S. diaconus). We confirmed the species- level dis-tinction of blue rockfish and deacon rockfish by using the results of genetic identification of individual fish from fin tissue samples and otoliths. Those results reveal the systematic rela-tionships of these species with other rockfish species and enabled an eval-uation of differences in distribution and life history (growth) between the 2 species in different management areas. Our evaluation of population structure found no significant differ-entiation within deacon rockfish and slight differentiation in blue rockfish that may not be biologically significant. Along the U.S. Pacific coast, deacon rockfish accounted for the majority of individuals sampled north of Monterey Bay, California, whereas blue rockfish were the more frequently observed species in waters of Monterey Bay and southern California. Modest but significant differences in growth parameters between the 2 species were observed by species, sex, and state (California or Oregon). The multidisciplinary nature of this study and the techniques and protocols we established provide a model for future research on and assessment of species complexes.
... Concordance with the results of Hannah et al. 5 is unsurprising because their age estimates compose a portion (~10%) of our data for deacon rockfish. However, McClure (1982) reported much larger sizes at age, possibly as a result of the use of surface reads instead of the break-and-burn technique (Laidig et al., 2003; this study), as surface reads may underestimate age in rockfish species (Chilton and Beamish, 1982;Munk, 2001). ...
To better inform stock assessment and management decisions, we used multiple approaches for esti-mating and comparing species- specific characteristics of the spatiotemporal composition of catch and life history traits of blue rockfish (Sebastes mystinus) and deacon rockfish (S. diaconus). We confirmed the species- level dis-tinction of blue rockfish and deacon rockfish by using the results of genetic identification of individual fish from fin tissue samples and otoliths. Those results reveal the systematic rela-tionships of these species with other rockfish species and enabled an eval-uation of differences in distribution and life history (growth) between the 2 species in different management areas. Our evaluation of population structure found no significant differ-entiation within deacon rockfish and slight differentiation in blue rockfish that may not be biologically significant. Along the U.S. Pacific coast, deacon rockfish accounted for the majority of individuals sampled north of Monterey Bay, California, whereas blue rockfish were the more frequently observed species in waters of Monterey Bay and southern California. Modest but signif-icant differences in growth parameters between the 2 species were observed by species, sex, and state (Califor-nia or Oregon). The multidisciplinary nature of this study and the techniques and protocols we established provide a model for future research on and assessment of species complexes.
... Perhaps not by coincidence, these patterns occur in organisms not studied (or even discovered!) when the classical theories of the evolution of senescence were developed. Some of these include Brandt's bat Myotis brandtii (Podlutsky, Khritankov, Ovodov, & Austad, 2005), barn owl Tyto alba (Altwegg, Schaub, & Roulin, 2007), greenland shark Somniosus microcephalus (Nielson et al., 2016), rockfishes (Cailliet et al., 2001;Mangel, Kindsvater, & Bonsall, 2007;Munk, 2001), ants and termites (Carey, 2001), naked mole-rat Heterocephalus glaber (Buffenstein, 2008), Hydra (Martínez, 1998;Schaible et al., 2015), bristlecone pine Pinus longaeva (Lanner & Connor, 2001), Borderea pyrenaica (García, Espadaler, & Olesen, 2012) and wilcox brush Eremophila forrestii (Ehrlén & Lehtilä, 2002 Figure 2. Note that changes in the shape of a Type II curve obligates either a Type I (a, d) or III (c, f) curve, but pace can drive a less severe slope, which takes its place in this graphic. Also, note that the difference in shape and pace curves among Type 3 (c, f) curves are more subtle than for Type I (a, d) curves; the difference between panels are most noticeable in how they intercept the x-axis. ...
Until recently, senescence was assumed to be a universal phenomenon. Evolutionary theories of senescence predict that no organism may escape the physiological decline that results in an increase in mortality risk and/or decline in fertility with age. However, evidence both in animals and plants has emerged in the last decade defying such predictions. Researchers are currently seeking mechanistic explanations for the observed variation in ageing trajectories. We argue that the historical view on the inevitability of senescence is due, in part, to the development of its classical theories, which targeted primarily unitary organisms. In unitary species, the integration of resources and functions is high, and adult size is determined. In contrast, the architecture of modular organisms is indeterminate and built upon repeated modules. The isolation of mortality risk in species like hydra (Hydra spp.) or creosote brush (Larrea tridentata) may explain their null or even negative senescence. Caleb Finch hypothesised three decades ago that species with the ability to compartmentalise risk may escape senescence. Here, we first review the evidence on organisms that slow down or even avoid senescence in the context of their architecture, along a continuum of unitarity‐modularity. Then, we use open‐access databases to comparatively analyse various moments of senescence and link longevity to the degree of anatomic modularity. Our analysis compares the pace of senescence across 138 plants and 151 animals, and the shape of senescence across a subset of these. Our comparative analysis reveals that plant species that are more modular do indeed tend to escape from senescence more often than those that are unitary. The role of modularity in animal senescence is less clear. In light of novel support for Finch's hypothesis across a large diversity of plant species, and with less conclusive findings in animals, we identify new research directions. We highlight opportunities related to age‐dependent mortality factors. Other areas for further research include the role of modularity in relation to endocrine actions, and the costs of modular anatomies.
... http://dx.doi.org/10.1101/771378 doi: bioRxiv preprint first posted online Sep. 18, 2019; include Brandt's bat (Myotis brandtii; Podlutsky et al. 2005), barn owl (Tyto alba;157 Altwegg, Schaub, and Roulin 2007), greenland shark (Somniosus microcephalus;158 Nielson et al. 2016), rockfishes (Cailliet et al. 2001;Mangel, Kindsvater and Bonsall 159 2007;Munk 2001), ants and termites (Carey 2001), naked mole-rat ( Heterocephalus 160 glaber; Buffenstein 2008), Hydra ( Schaible et al. 2015;Martínez 1998), bristlecone 161 pine (Pinus longaeva; Lanner and Connor 2001), Borderea pyrenaica (García, 162 Espadaler, Olesen 2012), and wilcox brush (Eremophila forrestii; Erlén and Lehtilä 163 2002). 164 ...
Until recently, senescence was assumed to be a universal phenomenon. Evolutionary theories of senescence predict that no organism may escape the physiological decline that results in an increase in mortality risk and/or decline in fertility with age. However, evidence both in animals and plants has emerged in the last decade defying such predictions. Researchers are currently seeking mechanistic explanations for the observed variation in ageing trajectories.
We argue that the historical view on the inevitability of senescence is due, in part, to the development of its classical theories, which targeted primarily unitary organisms. In unitary species, the integration of resources and functions is high, and adult size is determined. In contrast, the architecture of modular organisms is indeterminate and built upon repeated modules. The isolation of mortality risk in species like hydra ( Hydra spp. ) or creosote brush ( Larrea tridentata ) may explain their null or even negative senescence.
Caleb Finch hypothesised three decades ago that species with the ability to compartmentalise risk may escape senescence. Here, we first review the evidence on organisms that slow down or even avoid senescence in the context of their architecture, along a continuum of unitarity-modularity. Then, we use open-access databases to comparatively analyse various moments of senescence and link longevity to the degree of anatomic modularity. Our analysis compares 138 plants and 151 animals. Our comparative analysis reveals that plant species that are more modular do indeed tend to escape from senescence more often than those that are unitary. The role of modularity in animal senescence is less clear.
In light of novel support for Finch’s hypothesis across a large diversity of plant species, and with less conclusive findings in animals, we identify new research directions. We highlight opportunities related to age-dependent mortality factors. Other areas for further research include the role of modularity in relation to endocrine actions, and the costs of modular anatomies.
“The actinozooid is a living thing which knows no time of youthful vigour, no waxing to a period of adult life, no waxing to senility – it knows no age – it practically knows no natural death.” – Wood-Jones (1912)
... This is particularly true for long-lived marine fishes that exhibit extremely slow growth at older ages, which can result in closely spaced, difficult-to-interpret growth increments (Cailliet and Andrews 2008). As a result, validating the accuracy of methods used for age determination is especially important in long-lived, slow-growth species (Campana 2001;Munk 2001). ...
Current stock assessments for both the Warsaw Grouper Hyporthodus nigritus and the Snowy Grouper H. niveatus are based on age‐structured population models determined using traditional otolith‐based aging techniques. However, recent studies using bomb radiocarbon validation have shown that many deepwater fishes live much longer than previously estimated when relying on conventional age determination methods. In this study, we conducted bomb radiocarbon age validations of Warsaw Grouper and Snowy Grouper from the Gulf of Mexico. Radiocarbon age validation supported annual growth increment formation for all Warsaw Grouper size classes and medium‐sized Snowy Grouper. Conversely, ages of larger, older Snowy Grouper were greatly underestimated due to difficulty in discriminating annuli. This bomb radiocarbon analysis validates a minimum 56‐year longevity for both Warsaw Grouper and Snowy Grouper, increasing the currently published longevities of 41 and 54 years, respectively.
... The Yelloweye Rockfish Sebastes ruberrimus, like many other members of the genus Sebastes, is an extreme case with respect to many life history characteristics. Yelloweye Rockfish are among the longest living (Munk 2001) and latest maturing of all demersal-shelf rockfishes (Love et al. 2002). The maximum age for this species has been reported to be 121 years (O'Connell et al. 2002), and mean female age at maturity has been estimated to be 16-22 years at northern latitudes, with some immature individuals exceeding 30 years of age (Kronlund and Yamanaka 2001;O'Connell et al. 2002;Arthur 2020). ...
Spawning stock biomass (SSB) is often used as an index for reproductive potential (RP) in fisheries stock assessments. This method assumes that mature female biomass is proportional to total egg production and implies that (1) the fecundity–length relationship follows a cubic function or (2) relative fecundity is constant. For many marine fishes, adequate fecundity estimates to evaluate these relationships are lacking. This study estimated fecundity and fecundity relationships for Yelloweye Rockfish Sebastes ruberrimus and evaluated an automated method of counting eggs and larvae. We collected Yelloweye Rockfish ovaries (N = 90) from the northern Gulf of Alaska, including Prince William Sound, Alaska, during 2018–2019 and used the gravimetric method and image analysis software to count eggs from digital camera images. To evaluate the speed, accuracy, and precision of the automated counting procedure, one‐third of the gravimetric samples were also manually counted. Image analysis software was approximately four times faster but equally accurate and precise for fecundity estimates relative to manual counts. Fecundity ranged from 53,249 to 3.052 × 106 eggs (mean ± SD = 896,762 ± 699,504 eggs), and relative fecundity increased with female FL and ranged from 68 to 435 eggs/g of body weight (mean ± SD = 226 ± 87 eggs/g). The use of SSB for Yelloweye Rockfish stock assessment could underestimate the contribution to egg production by larger (>5.6‐kg) females, overestimate the contribution by smaller females, and lead to biased biological reference points. This study provides critical information to more realistically model RP and improve stock assessment inputs for the development of harvest control rules for Yelloweye Rockfish. Additionally, the use of image analysis software to count eggs in digital images proved to be an effective fecundity estimation method that could be applied to other highly fecund fish species for which the time demand of manual counting methods would be prohibitive.
The otolith morphology of 10 species belonging to the Carangidae family collected from the Persian Gulf and Oman Sea (coast of Iran). Were examined separately and the characteristics were drawn. The morphomttric parameters determined were total length (TL, mm), weight (W, gr), otolith length (OL, mm), weight of right otolith(WRO, mm), weight of left otolith(WLO, mm), height of right otolith (HRO, mm), height of left otolith (HLO, mm),. The values obtained from measurements are given in the 90% confidence interval in most spesies. The observation of this family three shape of sagittal, Sagitiform, Fusiform and Lanceolated. As a result of this analysis, it is possible to identify the species from the Carangidae family by the otolith characters.
Compliance is a key factor in ensuring success of marine conservation. We describe a community–academic partnership that seeks to reduce non-compliance of recreational fishers with Rockfish Conservation Areas (RCAs) around Galiano Island in British Columbia, Canada. Previous work showed mostly unintentional non-compliance by recreational fishers. From 2015 to 2018 we developed and implemented outreach and public education activities. We distributed information at community events, and installed 46 metal signs with maps of nearby RCAs at marinas, ferry terminals, and boat launches. During the summers of 2015, 2017, and 2018, we interviewed 86 recreational fishers to gauge their compliance with RCAs. Compared with a baseline in 2014, there was a reduction of 22% (from 25 to 3%) of people who unintentionally fished in RCAs with prohibited gears. In 2018, 67% of participants had seen our outreach materials. We used trail cameras overlooking RCAs to assess non-compliance in six locations on Galiano Island. Illegal fishing incidents within RCAs declined from 42% of days monitored in 2014 to 14% in 2018. Although our outreach efforts were limited in scale and scope, they appear to be making a difference. Our activities and findings can provide guidance for other regions seeking to improve compliance by recreational fishers.
Some time delay between materialization and production of any information is unavoidable, since there is always a time distance between these processes. As for the delay in materialization of genetic information, that is because the natural selection acts upon groups of living organisms on momentary basis whereas the selected information is realized in the following generations. And since the material world is always hanging,
some information about the structure of current successful individuals inevitably becomes outdated by the time their next generation appears. Organisms can often only reduce their lifespan to adapt to this henomenon. But among a huge quantity of structural elements that are formed based on “outdated” information, the ones that are able to improve individual fi tness with respect to the new state of the environment will be present with high probability. Such structural features may contain elements of ‘overadaptations’ or serve as anticipatory adaptations, that has allowed some species to persist during abrupt and unpredictable changes of their environment, when they did not have enough time for
gradual adaptation.
A planned change for the 2012 fishing year is that yellowtail and widow rockfish will be added to the 15 species that were part of the former "other slope rockfish" group to form a new management category in the Gulf of Alaska, "other rockfish". Previously, yellowtail and widow rockfish were part of the "pelagic shelf rockfish" group in the Gulf of Alaska, which will no longer exist in 2012. Also, for the first time, this year's assessment of "other slope rockfish"/ "other rockfish" is presented in its own separate SAFE chapter. In previous assessments since 2005, the assessment for "other slope rockfish" was combined with for shortraker rockfish in a joint chapter, although each was a separate management entity. Separating these into two chapters was a recommendation by the Gulf of Alaska Plan Team and the NPFMC Scientific and Statistical Committee. Assessment methodology in this report is identical to that used in the last full assessment for "other slope rockfish" in 2009. Changes in assessment inputs include new biomass estimates from the 2011 Gulf of Alaska trawl survey and a new estimate of natural mortality for harlequin rockfish. The new biomass estimates indicate a very large increase for silvergray rockfish, and this species now dominates the group. Biomass for harlequin rockfish remained quite low for the third survey in a row. A new natural mortality estimate of 0.09 was computed for harlequin rockfish; previously, a proxy estimate of 0.06 was used for this species in the computations of ABC and OFL.
Some time delay between materialization and production of any information is unavoidable, since there is always a time distance between these processes. As for the delay in materialization of genetic information, that is because the natural selection acts upon groups of living organisms on momentary basis whereas the selected information is realized in the following generations. And since the material world is always changing, some information about the structure of current successful individuals inevitably becomes
outdated by the time their next generation appears. Organisms can often only reduce their lifespan to adapt to this phenomenon. But among a huge quantity of structural elements that are formed based on “outdated” information, the ones that are able to improve
individual fi tness with respect to the new state of the environment will be present with high probability. Such structural features may contain elements of ‘overadaptations’ or serve as anticipatory adaptations, that has allowed some species to persist during abrupt and unpredictable changes of their environment, when they did not have enough time for gradual adaptation.
International and national laws governing the management of living marine resources generally require specification of harvest limits. To assist with the management of data-limited species, stocks are often grouped into complexes and assessed and managed as a single unit. The species that comprise a complex should have similar life history, susceptibility to the fishing gear, and spatial distribution, such that common management measures will likely lead to sustainable harvest of all species in the complex. However, forming complexes to meet these standards is difficult due to the lack of basic biological or fisheries data to inform estimates of biological vulnerability and fishery susceptibility. A variety of cluster and ordination techniques are applied to bycatch rockfish species in the Gulf of Alaska (GOA) as a case study to demonstrate how groupings may differ based on the multivariate techniques used and the availability and reliability of life history, fishery independent survey, and fishery catch data. For GOA rockfish, our results demonstrate that fishing gear primarily defined differences in species composition, and we suggest that these species be grouped by susceptibility to the main fishing gears while monitoring those species with high vulnerabilities to overfishing. Current GOA rockfish complex delineations (i.e., Other Rockfish and Demersal Shelf Rockfish) are consistent with the results of this study, but should be expanded across the entire GOA. Differences observed across species groupings for the variety of data types and multivariate approaches utilized demonstrate the importance of exploring a diversity of methods. As best practice in identifying species complexes, we suggest using a productivity-susceptibility analysis or expert judgment to begin groupings. Then a variety of multivariate techniques and data sources should be used to identify complexes, while balancing an appropriate number of manageable groups. Thus, optimal species complex groupings should be determined by commonality and consistency among a variety of multivariate methods and datasets.
Redbanded Rockfish (Sebastes babcocki) is found along the entire outer coast of British Columbia. It is caught by both the trawl and the hook-and-line commercial fisheries. The average annual commercial catch over the last 10 years (2004-2013) is 407 t, and over the last five years (2009-2013) is 342 t. Catches peaked at an estimated 1,360 t in 1992. The stock of Redbanded Rockfish along the Pacific coast of Canada has never been assessed using a population model.
We attempted to assess the status of the coastwide stock using an annual two-sex catch-at-age model, implemented in a Bayesian framework. The model was tuned to the following data: seven fishery-independent trawl survey series (including a novel series constructed from the annual International Pacific Halibut Commission longline survey), one fishery-independent hook-and-line survey series, annual estimates of commercial catch since 1940 from the trawl and hook-and-line fisheries, and age-composition data from the commercial fishery and surveys. The same modelling approach has been successfully used to assess stocks of other species of rockfish in Canadian Pacific waters.
However, for Redbanded Rockfish the data proved insufficient to yield reliable results from the model, despite numerous attempts using different assumptions and exclusion of various components of the data. In the simplest configurations we removed all of the age data, somewhat analogous to a surplus production model, but the Markov Chain Monte Carlo algorithm proved unstable.
We are therefore unable to provide specific quantitative advice to fisheries management, such as decision tables involving evaluation of current and future stock status relevant to reference points. We document all available data, including information on the species' biology, catch, fisheries management and our calculations of indices of abundance for the eight fishery-independent surveys. Catches have remained steady over the past eight years. We also present results of linear regressions on the survey indices. None of the regressions show a significant increasing or decreasing trend.
The biology and distribution of arrowtooth, Atheresthes stomias, and Kamchatka, A. evermanni, flounder were examined in Alaskan waters to determine whether there were sufficient differences to justify treating them as separate species in resource assessment surveys conducted by the National Marine Fisheries Service. Geographic ranges of the two flounder species overlap in Alaska waters; both occur in the eastern Bering Sea and western Aleutian Islands region. However, only arrowtooth flounder occur throughout the eastern Aleutian Islands region and the Gulf of Alaska. Arrowtooth flounder were abundant over a wide range of depths (76-450 m) and were more abundant than Kamchatka flounder in catches shallower than 325 m. Kamchatka flounder were abundant only in deep trawl hauls (226-500 m) and were more abundant than arrowtooth flounder in catches at depths greater than 375 m. Arrowtooth flounder were also abundant over a wide range of bottom-water temperatures (2.1°-4.6°C), whereas Kamchatka flounder were abundant in a much narrower range of bottom temperatures (3.8°-4.2°C). By percentage, females dominated the arrowtooth flounder population in the eastern Bering Sea (68.6%) and Aleutian Islands region (59.6%), whereas the Kamchatka flounder population was 55.9% and 47.5% female, respectively. The females of both species attained greater length at age than did the males. The difference in growth between the sexes was greater among arrowtooth flounder and may account for the preponderance of females in the arrowtooth flounder population.
Many laboratories rely on periodic rereading of reference collections of scales or otoliths to ensure that their age readers remain consistent in their age interpretations, both through time and with other age readers. Measures of both systematic difference (bias) and precision are required for this purpose, because measures of bias are not suitable as measures of precision, and vice versa. Using data from an age comparison study of haddock Melanogrammus aeglefinus for demonstration purposes, we evaluated a variety of graphical and statistical approaches for making paired age comparisons from the standpoint of both detecting age differences and assessing precision. Parametric and nonparametric matched-pair tests, regression analysis, analysis of variance, and age difference plots were all capable of detecting systematic over- or underaging. However, only the age bias plot was sensitive to both linear and nonlinear biases. The coefficient of variation (CV = SD/mean) was a robust measure of precision, whereas the widely used percent agreement statistic was not. The combination of an age bias plot, an age frequency table, and a CV provides a powerful and easily prepared comparison of matched pairs of age determinations.
Natural selection operates at the life history level to maximize the numberofsurviving offspring. Life history characteristics will vary in consistent patterns to meet this constraint. When theoretical patterns in life histories were investigated in terms of rand K selection and compared with actual trends in life history characteristics of fishes, the agreement between observed and predicted trends was significant. The effects of harvesting on stocks with these life history trends were investigated and it was found that K selected type species would be highly sensitive to overnshing and, once depleted, recovery would require a long time. The ecological and genetic properties of a species are intimately linked. The morphological and re productive characteristics, population sizes, and genetic frequencies ofspecies are adjusted to their environments by natural selection. Species in habiting different environments show different patterns of life history characteristics. The rela tionship among habitat, ecological strategies, and population parameters has been termed rand K selection (MacArthur and Wilson 1967) and/or op timallife histories (Gadgil and Bossert 1970). This body of theory is based on the assumption that natural selection operates on these characteristics in order to maximize the number of surviving offspring produced. Under an environmental re gime with a large component of unpredictable, nonselective, mortality an organism will allocate a larger portion of its resources to reproductive activities (anr strategist). Conversely the optimal allocation of resources for a population subjected to a high proportion ofpredictable, selective mor tality will be toward increasing individual fitness, frequently through competitive ability (a K strategist). With the number and variability of factors operating on any particular species, no species is going to be an r or K strategist in an absolute sense. A species will only occupy a rela tive position on the r andK continuum. In fisheries biology, the value of comparative studies of life history parameters has long been recognized (Holt 1962; Beverton 1963; Cushing 1971; Alverson and Carney 1975). These life his-
At the Alaska Fish eries Science Center. one in five age readings produced for routine stock assessments are re-aged indepen dently by a second age-reader. The Center now has a large database of repeated age readings that covers a variety of groundfish species and years. The purpose of this paper is to point out the problems and utility of interpreting such a database. The main problem of interpretation is fundamental, and relates to the fact that the true age of a fish is seldom known. Nevertheless, from a prag matic point of view, these data can still provide useful insights into the age-detennination process. Data from six marine fish species are used to show the overall levels of between reader bias, agreement, and variabil ity that have occurred on production age readings. Other uses for these data include objectively ranking the relative difficulty in ageing different species, maintaining quality control, examining between-reader differ ences in ageing criteria, and evalu ating the possible importance of between-reader bias and variability in later analysis and modeling ap plications. Assuming reader bias is negligible, modeling results pre sented here indicate that estimated percentage agreements are consis tent with the hypothesis that age determinations are normally distrib uted with a constant coefficient of variation over relatively wide age ranges. This result supports use of the coefficient of variation for mea suring variability in age precision studies. In this paper we evaluate a unique database developed for all marine fish species being routinely aged at the Alaska Fisheries Science Center. Here, large subsamples (one in five age readings produced for routine stock assessments) have been re-aged independently by a second experi enced age-reader, mainly for the pur pose of maintaining quality control. However, it became apparent that this database could be used to provide additional insights into the age-deter mination process. Most everyone familiar with the ageing of fish knows this process is fraught with difficulties. At the very least, there must be random variabil ity about some true age. Most likely there is also bias in the ageing meth odology at some ages, as well as between-reader differences. Because reader bias is probably affected by the individual reader, the true age of the fish being aged, and perhaps even individual fish, the analysis of re peated age readings made by differ ent readers does not easily fall under the purview of classical statistical theory. The types of analysis that can be
Examination of annular growth rings apparent in charred otolith cross sections is the basis for reports of extreme longevity in the rockfish genus Sebastes, but the interpretation of the annuli has long been disputed. We used a radiochemical assay of the otolith core to confirm our interpretation of annuli in Atlantic redfish, Sebastes mentella, to at least an age of 65 yr. Through measurement of the radioactive disequilibrium between 226Ra and 210Pb, it appears that redfish live to an age of at least 75 yr in the waters off of Nova Scotia.
Age determination of sablefish (Anoplopoma fimbria) is typically done by counting growth zones on the burnt cross-section of the otolith. The break-and-burn method of age determination is difficult to apply to sablefish. Therefore, we applied a relatively new method of fish age validation, using the disequilibrium of Pb-210/Ra-226 in the otoliths. This method of validation complements previous methods which used oxytetracycline (OTC) marking to validate incremental growth in sablefish otoliths. The Pb-210/Ra-226 disequilibria generally confirmed the ageing criteria used to interpret the otolith's burnt cross-section.
In 1978, tagged lingcod (Ophiodon elongatus) were injected with oxytetracycline to produce a time mark in the fin rays. Four fish were recovered after being at liberty for approximately 2 or .3 years and all had an oxytetracycline mark. Three of the four fish had formed a number of annual growth zones equivalent to the number of years at liberty, confirming that the mark thought to be an annulus did form once a year. One fish probably formed the appropriate number of annual growth zones but, because growth was reduced, the annuli were difficult to identify. There was no indication that the age of lingcod would be overestimated by the fin-ray method.
Age determination and validation studies on deep-water marine fishes indicate they are difficult to age and often long-lived. Techniques for the determination of age in individual fish includes growth-zone analysis of vertebral centra, fin rays and spines, other skeletal structures, and otoliths (there are three sets of otoliths in most bony fish semicircular canals, each of which is made of calcium carbonate). Most have regular increments deposited as the fish (and its semicircular canals) grows. The most commonly used otolith for age determination is the largest one called the sagitta. Age validation techniques include: (1) tag-recapture, often combined with oxytetracycline injection and analysis in growth-zones of bone upon recapture; (2) analysis of growth-zones over time; and (3) radiometric approaches utilizing a known radioactive decay series as an independent chronometer in otoliths from bony fishes. We briefly summarize previous studies using these three validation approaches and present results from several of our radiometric studies on deep-water, bony fishes recently subjected to expanding fisheries. Radiometric age validation results are presented for four species of scorpaenid fishes (the bank, Sebastes rufus, and bocaccio, S. paucispinis, rockfishes, and two thornyhead species, Sebastolobus altivelis and S. alascanus). In addition, our analysis of scorpaenids indicates that longevity increases exponentially with maximum depth of occurrence. The reason that the deep-water forms of scorpaenid fishes are long-lived is uncertain. Their longevity, however, may be related to altered physiological processes relative to environmental parameters like low temperature, high pressures, low light levels, low oxygen, and poor food resources.
A new technique is described in which age is estimated using multiple regression models based upon the measurable parameters otolith weight, otolith length, and otolith width in splitnose rockfish Sebastes diploproa, and canary rockfish S. pinniger. Models were calibrated using ages determined by interpretation of both whole otoliths and otolith sections which differ within these species, particularly at greater lengths. The models typically explained from 70-92% of variability in age depending upon species, sex, and method of age analysis. In another sample used to verify the precision of the models, variability associated with model-estimated ages was generally less than that induced by variability in ages between different agencies. -from Author splitnose rockfish Sebastes diploproa canary rockfish Sebastes pinniger
Age was determined in the fast growing canary rockfish Sebastes pinniger and the slow growing splitnose rockfish S. diploproa by different laboratories, techniques, and readers. Variability between agencies depended upon method and species. -from Sport Fishery Abstracts
The coefficients of variation and the index of precision provide a statistical test of reproducibility of aging between readers. Because the coefficients of variation and the index of precision incorporate the averaged year-class of a fish species, they are free from the shortcoming of the percent agreement method. Because variance is a better estimator than absolute difference, the coefficient of variation is a stronger estimator than the index of average percent error in providing a test statistic. -Author
Frank Rue -Commissioner Robert D. Mecum -Director, Commercial Fisheries 1 The Regional lnformation Report Series was established in 1987 to provide an information access system for all unpublished divisional reports. These reports frequently serve diverse ad hoc informational purposes or archive basic uninterpreted data. To accommodate timely reporting of recently collected information, reports in this series may contain preliminary data; this information may be subsequently finalized and published in the formal literature. Consequently, these reports should not be cited without prior approval of the author or the Division of Commercial Fisheries.
1 The Regional Information Report Series was established in 1987 to provide an information access system for all unpublished divisional reports. These reports frequently serve diverse ad hoc informational purposes or archive basic uninterpreted data. To accommodate timely reporting of recently collected information, reports in this series undergo only limited internal review and may contain preliminary data, this information may be subsequently finalized and published in the formal literature. Consequently, these reports should not be cited without prior approval of the author or the Division of Commercial Fisheries.
1 The Regional Information Report Series was established in 1987 to provide an information access system for all unpublished divisional reports. These reports frequently serve diverse ad hoc informational purposes or archive basic uninterpreted data. To accommodate timely reporting of recently collected information, reports in this series may contain preliminary data; this information may be subsequently finalized and published in the formal literature. Consequently, these reports should not be cited without prior approval of the author or the Division of Commercial Fisheries.
Natural levels of210Pb:226Ra in otoliths of orange roughy,Hoplostethus atlanticus, from south-east Australian waters, were measured to determine fish ages radiometrically. Up to maturity, radiometric age estimates were consistent with a single constant otolith growth rate. Radiometric ages for juveniles were comparable with, but greater than, those obtained in a recent, validated New Zealand study which employed counts of annuli on the surface of otoliths. Beyond maturity, radiometric ages were obtained by modelling with an otolith growth rate set at 45% of the juvenile rate. Radiometric ageing confirms that orange roughy is very slow-growing, with an age at maturity (32 cm standard length, SL) of ~ 32 yr, and is very long-lived, with fish 38 to 40 cm being 77 to 149 yr old. These results have important implications for the management of the fishery.
Fish ages are often estimated by assuming an annual frequency of the band-like, growth-zones recorded in the largest of their otoliths, the sagittae. The total number of growth-zones are normally determined either by counting external growth-zones (whole otolith technique) or by examining otolith cross-sections (otolith section technique). The two techniques do not always yield the same age, however, particularly in older specimens of certain fishes. To resolve this problem, otoliths of the splitnose rockfish Sebastes diploproa were examined morphologically and were assayed for their natural radionuclide concentrations. Four age groups of otoliths were identified based on growth-zone counting; in the first three, whole otolith and otolith section age estimates agreed, while in the fourth, the otolith section age substantially exceeded the whole otolith age. Radiometric analysis demonstrated that all otoliths were deficient in 210Pb activity relative to 226Ra activity with the deficiency decreasing with increasing number of growth-zones. The magnitude of the 210Pb/226Ra radioactive disequilibrium in each otolith group, when compared to the number of growth-zones and the otolith weight histories derived with the two techniques, identifies the growth-zones revealed by otolith sections as annual features. Thus when otolith section age exceeds whole otolith age (usually occurring after 20 to 25 yr of age for this species), the otolith section technique is the correct method of age determination. Estimates of longevity in the genus Sebastes near 80 yr are therefore confirmed.
Different ageing techniques affect not only the estimates of length at age but also estimates of population growth and mortality rates. This study considers these effects for the splitnose rockfish, Sebastes diploprod, and canary rockfish, S. pinnigec based on ages determined from the surfaces and sections of otoliths collected during a trawl survey off the west coast of North America i n 1980. Estimates of growth based o n surface rather than section ages were nearly identical for 5. dip/oprod but were higher for S. pinniger; slightly different whole otolith ageing techniques are suspected of producing these interspecific differences. For both species, however, estimates of mortality were reduced by more than half when section rather than surface ages were used. I N TRO D U CTI 0 N Ages of fish are needed to estimate two vital parameters of exploited fish populations, namely growth and mortality rates. Many fish species typically are aged by interpreting rings on the otolith, as is the case for rockfishes (Sebastes) for which the otolith is the preferred aeeine structure (Six and Horton 1977, Chilton and Beamish 1982). Various.. techniques have been developed to facilitate the detection and the interpretatioh of otolith patterns used in age determination (Chilton and Beamish 1982). Two methods to determine ages are counting the number of rings or annuli viewed on the exterior of the whole otolith (surface ages) or on a lateral cross section of the otolith (section ages). Section ages are often greater than surface ages for older specimens of many long-lived, slow-growing species (Beamish 1979a, 1979b, Boehlert and Yoklav-ich 19841, and recent evidence demonstrates that the section ages represent the true ages of fish (Bennett et al. 1982, Leaman and Nagtegaal 1987, Campana et al. in press). Because present evidence supports the validity of section ages for older fish, important biological and management implications could result if many demersal fish stocks are underaged due to the more common surface ageing ' Accepted for publication April 1990.
Optical fiber counts are used to determine asbestos exposure, so it is important to assess, control, and document the quality of those counts. These functions are the responsibility of the quality assurance (QA) coordinator in each laboratory. The QA coordinator must recognize that, compared to the analytical results for other substances, fiber count data are much more variable and have different statistical properties. These data, therefore, warrant special treatment. This article discusses the need to recount some samples, the procedures for determining bias and variability from these recount data, and the use of these statistics to test analytical results or assign confidence limits to them. Three kinds of bias and variability must be considered: intracounter, intra-laboratory, and interlaboratory. As data pairs (count and recount) are obtained, the first consideration is whether bias is present. If bias is detected in a set of data, that data should not be used for any purpose until the source of bias is investigated. Bias can be difficult to detect, and when not detected, the differences in the data are assumed to be variability. The procedures recommended in this article for determining variability are based on the relatively simple calculations of NIOSH Method 7400, but alternative calculations are also discussed. Variability is expressed as sr, which is an estimate of relative standard deviation.An example calculation of intracounter sr is given, along with an example of how to use this sr to test the quality of a fiber count for an individual sample. This test, which does not have great power, is meant to detect differences between a counter's historically established sr and the sr for the test sample. Such a difference indicates a problem with the sample or the analytical procedure, and as a guideline, fiber counts that fail the test should not be used to evaluate exposure. In an extension of the test given in NIOSH Method 7400, a guideline is given for deciding whether an entire sample set should be rejected based on the number of individual fiber counts rejected. Intralaboratory sr is an indicator of differences among counters within a laboratory, but these differences should be investigated for identifiable biases due to differences in training, visual acuity, or equipment. Interlaboratory sr can be calculated if samples are exchanged between laboratories. Interlaboratory sr is used to calculate a confidence interval about each analytical result, and that confidence interval should be reported as the analytical result. Analytical results reported for other substances do not include a confidence interval, but the analytical methods for other substances can be calibrated with readily available reference materials, thereby reducing the differences among laboratories. The nature of the fiber counting method and the lack of reference materials means that biases between laboratories are not easily corrected, or even identified. The confidence interval informs the person reading an analytical report about the differences among laboratories.
Precisions of estimated ages from vertebrae, cleithra, opercular bones, otoliths, and scales were measured in replicated trials on samples from lake trout Salvelinus namaycush from interior Alaska. Ages from all structures were similar for sexually immature lake trout. For mature lake trout, estimated ages from otoliths and from opercular bones were the most precise, although ages from opercular bones were significantly younger by a year than ages from otoliths. Estimated ages from cleithra and whole vertebrae were, respectively, too imprecise and too low for these structures to be useful in age validation studies. On this basis, otoliths and opercular bones can be used in age validation studies and scales can be used to estimate the age of immature lake trout.
The characteristics of lightly and heavily exploited Pacific ocean perch,Sebastes alutus, stocks are evaluated relative to the predictions of life history theory. These long-lived species (50–100 year lifespan)
show limited phenotypic plasticity and have little buffering against the effects of reduced lifespan. Reduced stock abundance
has generated some compensatory increase in growth rate. Length at first maturity varies only slightly with increased growth
rate, although age at maturity may decrease by 1–4 years. Grooth increases yield larger (15–20%) size at age and increased
reproductive effort at younger ages, but lower size-specific fecundity for these faster-growing fish. This suggests an energy
allocation protocol favouring growth over reproduction in these long-lived animals. Rockfishes have late recruitment to fisheries
(ages 10–15), and the detection time for results of management actions is equally long. Their vulnerability to overfishing
means that indices of population changes, more representative of fishing effects than the catch rate index presently used,
are required. Reproductive value indices are shown to be extremely sensitive and continuous with population abundance changes.
Their incorporation into monitoring programs would permit more timely evaluation of management actions. Management policies
developed for shorter-lived species are shown to be inappropriate for rockfishes. The need for an improved match in the time
frame of the species' life history, and that of management strategies, is stressed.
A compilation of values for the exponential coefficient of natural mortality (M) is given for 175 different stocks of fish distributed in 84 species, both freshwater and marine, and ranging from polar
to tropical waters. Values of L∞(LT, cm), W∞(g, fresh weight), K (1/year) and T (°C, mean annual water temperature) were attributed to each value of M, and the 175 sets of values plotted such that:
1) log M = −0·2107 − 0·0824 log W ∞ + 0·6757 log K + 0·4627 log T
and
2) log M = −0·0066 − 0·279 log L ∞ + 0·6543 log K + 0·4634 log T
The multiple correlation coefficients are for 1) 0·845, and for 2) 0·847, while the critical value (171 d.f.) is 0·275 (for
P = 0·01). All slopes are significantly ≠ 0 (for P = 0·001). The standard deviation of estimates of log M are for 1) 0·247, and for 2) 0·245.
The equations provide highly reliable estimates of M for any given fish stock, given the values of W ∞ or L ∞ and K of the von Bertalanffy growth formula, and an estimate of the mean water temperature in which the stock in question lives.
Only two groups have values of M generally differing from those obtained through the proposed equations: the Clupeidae, with generally lower and the polar
fishes with generally higher values. Correction factors are given for both groups. Potential applications of the findings
to population dynamics are discussed together with some ecological implications.
Age determination of shortspine thornyhead, Sebastes alascanus, using otolith sections and 210 Pb: 226 Ra ratios. National Marine Fisheries Service Southwest Fisheries Science Center
- J L Butler
- C Kastelle
- K Rubin
- D K.-H Heijnis
- L Jacobson
- A Andrews
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Butler, J. L., C. Kastelle, K. Rubin, D. K.-H. Heijnis, L.
Jacobson, A. Andrews, and W. W. Wakefield. 1995. Age
determination of shortspine thornyhead, Sebastes
alascanus, using otolith sections and 210 Pb: 226 Ra ratios.
National Marine Fisheries Service Southwest Fisheries
Science Center, Administrative Report, La Jolla, LJ-95-
12.
Arrowtooth flounder in Stock assessment and fishery evaluation (SAFE) report for the groundfish resources of the Gulf of Alaska
- B J Turnock
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Turnock, B. J., T. K. Wilderbuer, and E. S. Brown. 1999.
Arrowtooth flounder in Stock assessment and fishery evaluation (SAFE) report for the groundfish resources of the Gulf
of Alaska. North Pacific Fishery Management Council,
Anchorage, Alaska.
Slope rockfish. Pages 231294 in Stock assessment and fishery evaluation report for the groundfish resources of the Gulf of Alaska as projected for
- J Heifetz
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Heifetz, J, J. N. Ianelli, D. M. Clausen, D. L. Courtney, and J.
T. Fujioka. 2000. Slope rockfish. Pages 231294 in Stock
assessment and fishery evaluation report for the groundfish resources of the Gulf of Alaska as projected for 2001.
North Pacific Fishery Mangement Council, Anchorage,
Alaska.
Composition and biomass of the recreational rockfish Sebastes harvest in Southcentral Alaska Alaska Department of Fish and Game, Fishery Data Series No
- S C Meyer
Meyer, S. C. 2000. Composition and biomass of the recreational
rockfish Sebastes harvest in Southcentral Alaska, 1992
1995. Alaska Department of Fish and Game, Fishery Data
Series No. 00-6, Anchorage.
Ueber die Eizahl bei Pleuronectes platessa und die Altersbestimmung dieser Form aus den Otolithen. (The number of eggs in the Pleuronectes platessa and the fixing of its age by means of the otolith) Translated by
- J Reibisch
Reibisch, J. 1899. Ueber die Eizahl bei Pleuronectes platessa
und die Altersbestimmung dieser Form aus den Otolithen.
(The number of eggs in the Pleuronectes platessa and the
fixing of its age by means of the otolith). Translated by A.
T. A. Dobson. Wissenschaft liche Meeresuntersuchungen/
Abteilung Kiel Neue Folge 4:231248.
Rockfish assessment in Prince William Sound, Alaska. Alaska Department of Fish and Game, Division of Commercial Fisheries
- W R Bechtol
Bechtol, W. R. 2000. Rockfish assessment in Prince William
Sound, Alaska. Alaska Department of Fish and Game, Division of Commercial Fisheries, Regional Information Report 2A99-34, Anchorage.
Translation of: Rukovodstvo po isucheniy vozrasta i rosta ryb (Age and growth studies in fish) Translated from the Russian by the Israel Program for Scientific Translations Ltd
- N I Chugunova
Chugunova, N. I. 1963. Translation of: Rukovodstvo po
isucheniy vozrasta i rosta ryb (Age and growth studies in
fish). Translated from the Russian by the Israel Program
for Scientific Translations Ltd., Jerusalem. National Science Foundation, Washington, D.C. (original work published 1959).
How to age rockfish (Sebastes) using S. alutus as an example: the otolith burnt section technique
- S E Maclellan
MacLellan, S. E. 1997. How to age rockfish (Sebastes) using
S. alutus as an example: the otolith burnt section technique.
Canadian Technical Report of Fisheries and Aquatic Sciences 2146.
226 Ra determination of longevity in redfish
- Pb
Pb/ 226 Ra determination of longevity in redfish. Canadian
Journal of Fisheries and Aquatic Sciences 47:163165.
Abundance and composition of flatfish in Kachemak Bay
- W R Bechtol
- H Yuen
Bechtol, W. R., and H. Yuen. 1995. Abundance and composition of flatfish in Kachemak Bay, Alaska. Pages 497521
in Proceedings of the international symposium on North
Pacific flatfish, Alaska Sea Grant Report AK-SG-95-04,
Fairbanks.