Life history parameters of the crocodile shark, Pseudocarcharias kamoharai, in the tropical Atlantic Ocean

2021 ◽  
pp. 1-11
Author(s):  
Daniela Rosa ◽  
Marco Gago ◽  
Joana Fernandez-Carvalho ◽  
Rui Coelho
Keyword(s):  
Life History ◽  
Atlantic Ocean ◽  
Fork Length ◽  
Tropical Region ◽  
Age Validation ◽  
Growth Band ◽  
Longline Fisheries ◽  
Regional Fisheries Management Organizations ◽  
Best Fit ◽  
Pseudocarcharias Kamoharai

Abstract The crocodile shark (Pseudocarcharias kamoharai) is a small lamniform shark that is occasionally by-caught in pelagic longline fisheries targeting tunas and swordfish. Due to its biological features, this species is highly vulnerable to overexploitation. However, at present, the crocodile shark is not evaluated for its stock status by any of the Regional Fisheries Management Organizations. In this study, the biology of 391 specimens (220 females and 171 males), ranging from 44.2 cm to 101.5 cm fork length (FL), collected from the tropical region of the Atlantic Ocean, was examined. Ages were assigned from growth band counts in vertebral sections, with the modified von Bertalanffy growth model, using a fixed size at birth (L0) at 32 cm FL, producing the best fit: Linf = 105.6 cm FL and k = 0.14 y−1 for females; Linf = 94.6 cm FL and k = 0.18 y−1 for males. Maturity ogives were fitted to both length- and age-based data. The size (L50) and age (A50) at 50% maturity was estimated at 67.2 cm FL (5 years) and 81.6 cm FL (8 years) for males and females, respectively. Mean uterine fecundity was 3.7 pups per litter with a 1:1 embryonic sex ratio. Further work is needed regarding crocodile shark life-history characteristics, especially because there are no age validation studies of the band pair deposition periodicity. However, the parameters now presented can contribute to future evaluations of this species, which is especially important given its potentially vulnerable life history.

Review of the life history, fisheries, and stock assessment for small tunas in the Atlantic Ocean

2021 ◽  
Author(s):  
Flávia Lucena-Frédou ◽  
Bruno Mourato ◽  
Thierry Frédou ◽  
Pedro G. Lino ◽  
Rubén Muñoz-Lechuga ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Ocean ◽  
Stock Assessment

AGE AND GROWTH OF THE BLUE SHARK PRIONACE GLAUCA IN THE EASTERN ATLANTIC OCEAN

KSTU News ◽  
2021 ◽  
pp. 11-25
Author(s):  
Beraki Weldegiorgish Teklekhaimanot ◽  
Sergey Vadimovich Shibaev ◽  
Sergey Yurievich Gulyugin
Keyword(s):  
Atlantic Ocean ◽  
Growth Parameters ◽  
Growth Function ◽  
Age And Growth ◽  
Growth Band ◽  
Prionace Glauca ◽  
Western Africa ◽  
Eastern Atlantic Ocean ◽  
Digital Microscope ◽  
Central Atlantic

In this study, 292 blue sharks Prionace glauca (Linnaeus, 1758) (from 151 to 305 cm total length, TL) were collected off western Africa in the eastern central Atlantic Ocean between 1980 and 1982. Vertebral sections of females specimens ranged from 175 to 300 cm and males specimens ranged from 166 to 312 cm TL were processed and analyzed for age and growth parameters. Growth band pairs (translucent and opaque bands) were counted on the images photographed from the stained whole vertebrae using digital microscope called Digi Scope II. The band pairs after the birthmark were counted from 3 to 12 for males and from 4 to 13 for females. Growth parameters were derived using the Von Bertalanffy growth function (VBGF) based on FISAT and solver solution Microsoft excel and Ford Wall-Ford. VBGF was that which best fit the data. Parameters derived from the combination of observed and back-calculated lengths, K = 0.1, L_∞ = 386.4 cm and t_0 = −1.35 year for males and K = 0.12 year -1, L_∞= 355 cm and t_0 = –1.02 year for females were considered to best describe growth. The longevity was estimated to be at least 23.7 and 28.3 years for females and males respectively. The natural mortality rate was estimated to be 0.15 year - 1 and 0.18 year -1 for males and females respectively.

Slow life-history traits of a neritic predator, the bronze whaler (Carcharhinus brachyurus)

2017 ◽  
Vol 68 (3) ◽  
pp. 461 ◽  
Author(s):  
Michael Drew ◽  
Paul Rogers ◽  
Charlie Huveneers
Keyword(s):  
Life History ◽  
Growth Parameters ◽  
Isolated Populations ◽  
Life History Characteristics ◽  
Regional Estimates ◽  
Males And Females ◽  
Size At Age ◽  
Slow Growing ◽  
Best Fit ◽  
Age Estimates

Intra-species plasticity in the life-history characteristics of sharks leads to the need for regional estimates to accurately determine resilience to anthropogenic effects. The present study provides the first length-at-age, growth and maturity estimates for the bronze whaler (Carcharhinus brachyurus) from southern Australia. Age estimates were obtained from vertebral sections of 466 individuals spanning 50–308-cm total length. Maximum estimates of age for males and females were 25 and 31 years respectively. The three-parameter logistic model for females (L∞=308cm LT, k=0.15, α=742) and for males (L∞=317cm LT, k=0.13, α=782) provided the best fit to the size at age data. Males matured at a similar age (16 years), but smaller size than females (224v. 270cm LT). Growth parameters and age-at-maturity estimates were similar to those for genetically isolated C. brachyurus populations, and the sympatric dusky shark (C. obscurus). The southern Australian C. brachyurus population is long-lived, slow growing and late maturing. These growth parameters are needed to undertake demographic analyses to assess the resilience of C. brachyurus to fishing, and provide an example of a wide-ranging elasmobranch with similar life-history characteristics across isolated populations.

Assessing growth band counts from vertebrae and dorsal-fin spines for ageing sharks: comparison of four methods applied to Heterodontus portusjacksoni

2009 ◽  
Vol 60 (9) ◽  
pp. 898 ◽  
Author(s):  
Javier Tovar-Ávila ◽  
Christopher Izzo ◽  
Terence I. Walker ◽  
J. Matías Braccini ◽  
Robert W. Day
Keyword(s):  
Shark Species ◽  
Systematic Bias ◽  
Age Validation ◽  
Growth Band ◽  
Dorsal Fin ◽  
Growth Bands ◽  
Visible Growth ◽  
Port Jackson ◽  
First Time ◽  
Fin Spines

Four methods for counting growth bands using vertebrae and dorsal-fin spines of the Port Jackson shark, Heterodontus portusjacksoni, are compared. Both calcified structures presented observable growth bands, allowing cross comparison among structures for the first time in a shark species. Whole and sectioned vertebrae and dorsal fin-spines possess highly visible growth bands and intra-reader band counts resulted in similar precision indices with little systematic bias. However, inter-reader growth band count plots showed possible biases in counts from sectioned vertebrae and sectioned dorsal-fin spines. Sectioned vertebrae and whole and sectioned dorsal-fin spines produced similar growth band counts, whereas whole vertebrae produced significantly lower counts. The similar readability, precision indices, growth band counts and apparent absence of biases between counts for a single reader would indicate that sectioned vertebrae and whole and sectioned dorsal-fin spines are both potentially useful and acceptable methods for band counting. However, inter-reader comparisons are necessary to avoid acceptance of biased estimations, resulting in over- or under-estimations of age. Validation for all age classes is essential to determining accurate age estimations for this and other species.

scholarly journals From Environment to Mating Competition and Super-K in a Predominantly Urban Sample of Young Adults

2017 ◽  
Vol 15 (1) ◽  
pp. 147470491667016 ◽  
Author(s):  
George B. Richardson ◽  
Jacinda K. Dariotis ◽  
Mark H. C. Lai
Keyword(s):  
Young Adults ◽  
Life History ◽  
Young Adulthood ◽  
Life History Theory ◽  
Human Life ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Mating Competition ◽  
Urban Sample ◽  
Best Fit

Recent research suggests human life history strategy (LHS) may be subsumed by multiple dimensions, including mating competition and Super-K, rather than one. In this study, we test whether a two-dimensional structure best fit data from a predominantly urban sample of young adults ages 18–24. We also test whether latent life history dimensions are associated with environmental harshness and unpredictability as predicted by life history theory. Results provide evidence that a two-dimensional model best fit the data. Furthermore, a moderate inverse residual correlation between mating competition and Super-K was found, consistent with a life history trade-off. Our findings suggest that parental socioeconomic status may enhance investment in mating competition, that harshness might persist into young adulthood as an important correlate of LHS, and that unpredictability may not have significant effects in young adulthood. These findings further support the contention that human LHS is multidimensional and environmental effects on LHS are more complex than previously suggested. The model presented provides a parsimonious explanation of an array of human behaviors and traits and can be used to inform public health initiatives, particularly with respect to the potential impact of environmental interventions.

Life-history traits of a small-bodied coastal shark

2013 ◽  
Vol 64 (1) ◽  
pp. 54 ◽  
Author(s):  
Adrian N. Gutteridge ◽  
Charlie Huveneers ◽  
Lindsay J. Marshall ◽  
Ian R. Tibbetts ◽  
Mike B. Bennett
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Logistic Function ◽  
Early Maturation ◽  
Large Size ◽  
History Of ◽  
Age Model ◽  
Best Fit ◽  
Combined Data

The life histories of small-bodied coastal sharks, particularly carcharhinids, are generally less conservative than those of large-bodied species. The present study investigated the life history of the small-bodied slit-eye shark, Loxodon macrorhinus, from subtropical Hervey Bay, Queensland, and compared this species' biology to that of other coastal carcharhinids. The best-fit age model provided parameters of L∞ = 895 mm total length (TL), k = 0.18 and t0 = –6.3 for females, and L∞ = 832 mm TL, k = 0.44 and t0 = –2.6 for males. For sex-combined data, a logistic function provided the best fit, with L∞ = 842 mm TL, k = 0.41 and α = –2.2. Length and age at which 50% of the population was mature was 680 mm TL and 1.4 years for females, and 733 mm TL and 1.9 years for males. Within Hervey Bay, L. macrorhinus exhibited an annual seasonal reproductive cycle, producing an average litter of 1.9 ± 0.3 s.d. With the exception of the low fecundity and large size at birth relative to maximum maternal TL, the life-history traits of L. macrorhinus are comparable to other small-bodied coastal carcharhinids, and its apparent fast growth and early maturation contrasts that of large-bodied carcharhinids.

Age, growth, and mortality of wahoo, Acanthocybium solandri, from the Atlantic coast of Florida and the Bahamas

2008 ◽  
Vol 59 (9) ◽  
pp. 799 ◽  
Author(s):  
Richard S. McBride ◽  
Adam K. Richardson ◽  
Kristin L. Maki
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic Ocean ◽  
Growth Parameters ◽  
Atlantic Coast ◽  
Fork Length ◽  
First Year ◽  
The Bahamas ◽  
Western Atlantic ◽  
Large Size ◽  
The 1960S

Wahoo, Acanthocybium solandri, constitute an economically important fishery for many coastal nations, but assessment of this living marine resource is hampered by a lack of basic life history information. The present study demonstrates that wahoo in the western North Atlantic Ocean are short lived, grow rapidly in their first year, achieve a very large size, and have high mortality rates. The largest individuals were female and the sex ratio was significantly female-biased (298 females: 223 males: 54 unknown sex). An edge analysis showed that annuli formed primarily during winter–spring, which supported the use of sectioned otoliths for ageing wahoo. Wahoo lived a median of 1.3 years, a mean of 1.8 years, and a maximum of 9.3 years (n = 469). They had a high instantaneous mortality rate (Z = 0.98), and they grew rapidly and to a large size; von Bertalanffy growth parameters were: L∞ = 1701 mm fork length (FL), K = 0.381, to = –1.63. Females had a very similar maximum age relative to males (maximum age 9.3 v. age 9.1 years), and they had a slightly, but not significantly, lower mortality (Z = 0.91 v. 1.1) than males. Females grew slightly, although not significantly, larger than males (L∞ = 1797 v. 1555 mm FL, maximum observed = 1804 v. 1585 mm FL). Presumably the piscivorous nature of wahoo feeding, as noted by others, fuels these fast growth rates. Comparative data are very limited but it appears that the survival rate of wahoo in the western Atlantic Ocean is not different now than in the 1960s.

scholarly journals Age-based and reproductive biology of the Pacific Longnose Parrotfish Hipposcarus longiceps from Guam

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4079 ◽  
Author(s):  
Brett M. Taylor ◽  
Eric Cruz
Keyword(s):  
Life History ◽  
Fishery Management ◽  
Stock Assessment ◽  
Fork Length ◽  
Growth Patterns ◽  
Life History Trait ◽  
Fishery Resource ◽  
Species Vulnerability ◽  
The Pacific ◽  
Improved Model

The Pacific longnose parrotfish Hipposcarus longiceps (Valenciennes 1840) represents a prime fishery resource throughout much of the tropical Pacific. In this study, we sampled the species from the Guam commercial fishery market across five consecutive years to characterize reproductive and age-based demographic information imperative for informed fishery management. Compared with other parrotfishes, this species was found to be large-bodied, but has only a moderate life span of 10 + years. Hipposcarus longiceps was confirmed as a diandric protogynous hermaphrodite with highly sex-specific growth patterns and an overall mean asymptotic length of 434 mm fork length (FL). Females were estimated to reach median maturity at 329 mm FL (2.4 years) and have a median length at female-to-male sex change of 401 mm FL. Life-history trait values derived here were used to update previous models relating life history and vulnerability to overexploitation. We found that enhancement of just one species’ trait values improved model fits considerably, which strengthens the conclusion that life-history traits are a strong determinant of species’ vulnerability in the parrotfishes. This information is an imperative complement to other data sources facilitating formal stock assessment of a key fishery target.

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