scholarly journals A first estimate of white shark, Carcharodon carcharias , abundance off Central California

2011 ◽  
Vol 7 (4) ◽  
pp. 581-583 ◽  
Author(s):  
Taylor K. Chapple ◽  
Salvador J. Jorgensen ◽  
Scot D. Anderson ◽  
Paul E. Kanive ◽  
A. Peter Klimley ◽  
...  
Keyword(s):  
Conservation Status ◽  
White Shark ◽  
Carcharodon Carcharias ◽  
Central California ◽  
Photo Identification ◽  
Marine Predators ◽  
Northeastern Pacific ◽  
The Status ◽  
Credible Intervals ◽  
Guadalupe Island

The decline of sharks in the global oceans underscores the need for careful assessment and monitoring of remaining populations. The northeastern Pacific is the home range for a genetically distinct clade of white sharks ( Carcharodon carcharias ). Little is known about the conservation status of this demographically isolated population, concentrated seasonally at two discrete aggregation sites: Central California (CCA) and Guadalupe Island, Mexico. We used photo-identification of dorsal fins in a sequential Bayesian mark–recapture algorithm to estimate white shark abundance off CCA. We collected 321 photographs identifying 130 unique individuals, and estimated the abundance off CCA to be 219 mature and sub-adult individuals ((130, 275) 95% credible intervals), substantially smaller than populations of other large marine predators. Our methods can be readily expanded to estimate shark population abundance at other locations, and over time, to monitor the status, population trends and protection needs of these globally distributed predators.

Concordance of genetic and fin photo identification in the great white shark, Carcharodon carcharias, off Mossel Bay, South Africa

2009 ◽  
Vol 156 (10) ◽  
pp. 2199-2207 ◽  
Author(s):  
Chrysoula Gubili ◽  
Ryan Johnson ◽  
Enrico Gennari ◽  
W. Hermann Oosthuizen ◽  
Deon Kotze ◽  
...  
Keyword(s):  
South Africa ◽  
White Shark ◽  
Carcharodon Carcharias ◽  
Photo Identification ◽  
Great White Shark

Impact of satellite linked radio transmitting (SLRT) tags on the dorsal fin of subadult and adult white sharks (Carcharodon carcharias)

2020 ◽  
Vol 96 (1) ◽  
pp. 23-30
Author(s):  
Nicole Nasby-Lucas ◽  
Michael L Domeier
Keyword(s):  
South Africa ◽  
High Accuracy ◽  
Tracking Data ◽  
Carcharodon Carcharias ◽  
Dorsal Fin ◽  
Northeastern Pacific ◽  
Real Time Tracking ◽  
Guadalupe Island ◽  
Marine Wildlife

Satellite linked radio transmitting (SLRT) tags provide long-term, high accuracy, near real-time tracking data for marine wildlife. Adult white sharks (Carcharodon carcharias Linnaeus, 1758) in the northeastern Pacific at both Guadalupe Island, Mexico and Southeast Farallon Island, USA were tagged with SLRT oval and inline finmout tags. These tags provided up to 7.4 yrs of tracking data. A previous study showed structural dorsal fin damage for SLRT tagged juvenile and subadult white sharks off South Africa. Sharks tagged in the northeastern Pacific were resighted between 1 and 11 yrs post tagging and included 10 adults and 2 subadults. Sharks that were resighted did not exhibit significant fin deformation, although in one case the oval finmount tag did cause bending of the dorsal fin due to tag shape, weight, and placement of the tag on the dorsal fin. Four inline tags came off after deployments of at least 2.2 to 3.7 yrs (based on date of last message received), and two of these caused a tear to the trailing edge of the dorsal fin upon release. Overall, SLRT tags provided long-term tracking data and there was no apparent impact on the behavior or migration cycles of the sharks. Serious dorsal fin deformation seems to occur in the case of juvenile and subadult white sharks where the fin is rapidly growing and thus for tracking juvenile white sharks, alternate methods should be considered.

Population metrics and movement of two sympatric carcharhinids: a comparison of the vulnerability of pelagic sharks of the southern Australian gulfs and shelves

2013 ◽  
Vol 64 (1) ◽  
pp. 20 ◽  
Author(s):  
P. J. Rogers ◽  
C. Huveneers ◽  
S. D. Goldsworthy ◽  
W. W. L. Cheung ◽  
G. K. Jones ◽  
...  
Keyword(s):  
Sympatric Species ◽  
White Shark ◽  
Logic Model ◽  
Shark Species ◽  
Carcharodon Carcharias ◽  
Marine Predators ◽  
Management Measures ◽  
Dusky Shark ◽  
Carcharhinus Obscurus ◽  
Relative Vulnerability

The dusky shark Carcharhinus obscurus and the bronze whaler Carcharhinus brachyurus are large-bodied, marine predators that inhabit coastal and shelf waters of southern Australia. C. obscurus is considered to be among the most vulnerable pelagic sharks to overexploitation. This study focussed on population metrics and movement patterns of these sympatric species. Litters from two pregnant C. brachyurus were examined; these comprised 20 and 24 embryos, respectively. Tagging data indicated that 75% of whaler sharks tagged in this region by recreational fishers were juveniles, and 58% of recaptures occurred within 50 km of the tagging locations. Fishery catch samples comprised 99% juvenile C. brachyurus and C. obscurus. Our findings suggested that semi-protected gulf waters represented ecologically significant habitats of juveniles. A fuzzy-logic model showed that in terms of relative vulnerability to fishing, C. brachyurus ranked in the mid to lower end of the spectrum, when compared with six sympatric pelagic shark species, including the white shark, Carcharodon carcharias. Our findings emphasised a need for improvement to management measures for these carcharhinids, which are likely to play a significant role in the functioning of the temperate gulf and shelf ecosystems.

Spatiotemporal Patterns of White Shark (Carcharodon carcharias) Predation at the South Farallon Islands, California

Copeia ◽  
1992 ◽  
Vol 1992 (3) ◽  
pp. 680 ◽  
Author(s):  
A. Peter Klimley ◽  
Scot D. Anderson ◽  
Peter Pyle ◽  
R. P. Henderson
Keyword(s):  
White Shark ◽  
Spatiotemporal Patterns ◽  
The South ◽  
Carcharodon Carcharias

scholarly journals Ground beetles (Carabidae) of field margin habitats

Biologia ◽  
2020 ◽  
Vol 75 (10) ◽  
pp. 1631-1641
Author(s):  
Janina Bennewicz ◽  
Tadeusz Barczak
Keyword(s):  
Conservation Status ◽  
Ground Beetle ◽  
Abundant Species ◽  
Ground Beetles ◽  
Field Margin ◽  
Poecilus Cupreus ◽  
The Status ◽  
Beetle Assemblages ◽  
Anchomenus Dorsalis ◽  
Pterostichus Melanarius

Abstract The aim of this study was to identify the role of field margin habitats in preserving the diversity and abundance of ground beetle assemblages, including potentially entomophagous species and those with conservation status in Poland. Research material was collected in 2006–2007 in four types of margin habitats – a forest, bushes, ditches and in two arable fields. Insects were captured into pitfalls, without preservation liquid or bait added to the traps. Traps were inspected twice a week, between May and August, and one sample was a weekly capture. In field margin habitats the most abundant species were Limodromus assimilis, Anchomenus dorsalis, Pterostichus melanarius and Carabus auratus. A lower abundance of species was noted on fields, with dominant Poecilus cupreus and P. melanarius. The group of zoophagous carabids found in our study includes 30 species from field margin habitats, i.e. 37.5% of all captured Carabidae taxa and 58.3% of all specimens. The share of aphidophagous species was 84.9% among bushes, 86.7% near ditches, and 88.0% in the forest habitat. Several species captured during the study are under protection in Poland. These include the partly protected Carabus convexus, which also has the status of near threatened species, the partly protected Calosoma auropunctatum, and Broscus cephalotes. Considering all the investigated field margin habitats, ground beetles were most numerous in the oak-hornbeam habitat, defined as bushes, formed predominantly by Prunus spinosa, Crataegus leavigata, Sambucus nigra and Rosa canina. Thus, this habitat was the most important reservoir/refugium for the ground beetles.

scholarly journals DNA barcode identification of commercial fish sold in Mexican markets

Genome ◽  
2018 ◽  
Vol 61 (6) ◽  
pp. 457-466 ◽  
Author(s):  
Stephanie Sarmiento-Camacho ◽  
Martha Valdez-Moreno
Keyword(s):  
Conservation Status ◽  
Dna Barcode ◽  
Common Species ◽  
Morphological Identification ◽  
Dna Barcodes ◽  
Commercial Fish ◽  
Sphyrna Lewini ◽  
Pangasianodon Hypophthalmus ◽  
Makaira Nigricans ◽  
The Status

The substitution of high-value fish species for those of lower value is common practice. Although numerous studies have addressed this issue, few have been conducted in Mexico. In this study, we sought to identify fresh fillets of fish, sharks, and rays using DNA barcodes. We analyzed material from “La Viga” in Mexico City, and other markets located on the Gulf and Caribbean coasts of Mexico. From 134 samples, we obtained sequences from 129, identified to 9 orders, 28 families, 38 genera, and 44 species. The most common species were Seriola dumerili, Pangasianodon hypophthalmus, Carcharhinus falciformis, Carcharhinus brevipinna, and Hypanus americanus. Pangasianodon hypophthalmus was most commonly used as a substitute for higher-value species. The substitution rate was 18% of the total. A review of the conservation status of the specimens identified against the IUNC list enabled us to establish that some species marketed in Mexico are threatened: Makaira nigricans, Lachnolaimus maximus, Hyporthodus flavolimbatus, and Isurus oxyrinchus are classified as vulnerable; Lopholatilus chamaeleonticeps and Sphyrna lewini are endangered; and the status of Hyporthodus nigritus is critical. These results will demonstrate to the Mexican authorities that DNA barcoding is a reliable tool for species identification, even when morphological identification is difficult or impossible.

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