Spinner Shark Carcharhinus Brevipinna Research Articles

Pola Pertumbuhan dan Faktor Kondisi Hiu Merak Bulu Carcharhinus brevipinna di Perairan Selatan Nusa Tenggara

<strong>Growth Pattern and Condition Factor of Spinner Shark Carcharhinus brevipinna in Southern Nusa Tenggara Waters.</strong> The spinner sharks are one of shark commodities that are utilized optimally from the southern of Nusa Tenggara waters, however, the scientific information is still limited. This study aimed to assess the growth pattern and condition factors of the spinner shark, <em>Carcharhinus brevipinna</em> in southern Nusa Tenggara waters. The research was conducted from January to December 2016 using direct recording of the catch data. Information on length, weight and sex determinations were collected by the enumerator. The data was analysed descriptively with the shark condition was determined based on the relative condition factor obtaining from the length-weight relationship. The results showed that growth patterns of the spinner shark, both males and females, were allometrically negative. The relative condition factors of the catch of male sharks were ranged from 0.206 – 2.225 and females from 0.237 – 3.361. The condition factors of spinner sharks were not different between sexes and time of fishing, but they were different in length classes.

Isolation and characterization of eight microsatellite loci from Galeocerdo cuvier (tiger shark) and cross-amplification in Carcharhinus leucas, Carcharhinus brevipinna, Carcharhinus plumbeus and Sphyrna lewini.

The tiger shark Galeocerdo cuvier (Carcharhinidae) is a large elasmobranch suspected to have, as other apex predators, a keystone function in marine ecosystems and is currently considered Near Threatened (Red list IUCN). Knowledge on its ecology, which is crucial to design proper conservation and management plans, is very scarce. Here we describe the isolation of eight polymorphic microsatellite loci using 454 GS-FLX Titanium pyrosequencing of enriched DNA libraries. Their characteristics were tested on a population of tiger shark (n = 101) from Reunion Island (South-Western Indian Ocean). All loci were polymorphic with a number of alleles ranging from two to eight. No null alleles were detected and no linkage disequilibrium was detected after Bonferroni correction. Observed and expected heterozygosities ranged from 0.03 to 0.76 and from 0.03 to 0.77, respectively. No locus deviated from Hardy-Weinberg equilibrium and the global FIS of the population was of 0.04NS. Some of the eight loci developed here successfully cross-amplified in the bull shark Carcharhinus leucas (one locus), the spinner shark Carcharhinus brevipinna (four loci), the sandbar shark Carcharhinus plumbeus (five loci) and the scalloped hammerhead shark Sphyrna lewini (two loci). We also designed primers to amplify and sequence a mitochondrial marker, the control region. We sequenced 862 bp and found a low genetic diversity, with four polymorphic sites, a haplotype diversity of 0.15 and a nucleotide diversity of 2 × 10−4.

Characterisation and cross-amplification of 21 novel microsatellite loci for the dusky shark, Carcharhinus obscurus

The dusky shark Carcharhinus obscurus risks excessive fisheries exploitation worldwide due to its low productivity. Genetic monitoring is an effective way of resolving species stock structure, genetic diversity, and forensically identifying processed animals. Here we present the first C. obscurus species-specific microsatellite loci. Twenty-one di- to tetra-nucleotide loci with between 2 and 20 alleles per locus were developed. Observed heterozygosity ranged from 0.28 to 0.91 with only one locus slightly deviating from Hardy–Weinberg equilibrium. No significant evidence for null alleles or linkage disequilibrium was detected. These loci were cross-amplified in three related species. Seventeen, twelve, and eighteen loci exhibited polymorphism in sandbar shark Carcharhinus plumbeus, spinner shark Carcharhinus brevipinna, galapagos shark Carcharhinus galapagensis, respectively. Investigations into C. obscurus will benefit from these loci which possess attributes suitable for population-scale and individual-scale analyses. Additionally locus cross-amplification will facilitate research for these species with few existing microsatellites and similarly vulnerable life-histories.

Characterisation and cross-amplification of 19 novel microsatellite loci for the sandbar shark, Carcharhinus plumbeus

Conservation of vulnerable shark species that are also heavily exploited, such as the sandbar shark Carcharhinus plumbeus is a pressing issue, and molecular genetics is an increasingly important population monitoring and species identification tool. Here we present 19 C. plumbeus microsatellite loci with a broad range of alleles per locus (3–22), and observed heterozygosities (0.17–0.95). Null alleles were not apparent and if present, were at frequencies <0.041. None of the loci showed significant deviation from Hardy–Weinberg equilibrium or indications of linkage disequilibrium. Cross-species amplification of these loci in three other carcharinids, dusky shark Carcharhinus obscurus, spinner shark Carcharhinus brevipinna, and galapagos shark Carcharhinus galapagensis showed polymorphism in 13, 13, and 14 loci respectively. These highly diverse loci will assist both individual-specific and population-wide genetic investigations for these species.

Sharks of the Persian (Arabian) Gulf: a first annotated checklist (Chondrichthyes: Elasmobranchii)

The first evidence-based checklist of sharks of the Persian (Arabian) Gulf is presented based on appraisal of primary lit-erature and new data, including identifications verified by COI barcoding. Evidence of the occurrence of 26 species in theGulf is presented, and the possible presence of a further 17 species is discussed. Carcharhinidae is the most species-richfamily (16 species) present. The first substantiated Gulf records of the spinner shark Carcharhinus brevipinna, blacktipreef shark C. melanopterus¸ and scalloped hammerhead Sphyrna lewini are provided, along with a new record of the rarelyreported grey nurse shark Carcharias taurus. The diversity of the Gulf’s shark fauna, and possible influences on it, are briefly discussed.

Relative abundance and size of coastal sharks derived from commercial shark longline catch and effort data

In the north-west Atlantic Ocean, stock assessments conducted for some commercially harvested coastal sharks indicate declines from 64 to 80% with respect to virgin population levels. While the status of commercially important species is available, abundance trend information for other coastal shark species in the north-west Atlantic Ocean are unavailable. Using a generalized linear modelling (GLM) approach, a relative abundance index was derived from 1994 to 2009 using observer data collected in a commercial bottom longline fishery. Trends in abundance and average size were estimated for bull shark Carcharhinus leucas, spinner shark Carcharhinus brevipinna, tiger shark Galeocerdo cuvier and lemon shark Negaprion brevirostris. Increases in relative abundance for all shark species ranged from 14% for C. brevipinna, 12% for C. leucas, 6% for N. brevirostris and 3% for G. cuvier. There was no significant change in the size at capture over the time period considered for all species. While the status of shark populations should not be based exclusively on abundance trend information, but ultimately on stock assessment models, results from this study provide some cause for optimism on the status of these coastal shark species.

SIZE, SEX AND LENGTH AT MATURITY OF FOUR COMMON SHARKS CAUGHT FROM WESTERN INDONESIA

A study on four common shark species in Indonesia, the spinner shark Carcharhinus brevipinna (Muller and Henle, 1839), silky shark Carcharhinus falciformis (Bibron, 1839), spot-tail shark Carcharhinus sorrah (Valenciennes, 1839) and scalloped hammerhead Sphyrna lewini (Griffith and Smith, 1834) was conducted at several shark landing sites in western Indonesia from March 2002 to December 2004. Data were collected from the surveyed areas including the length of frequency, sex composition and length at maturity. In general, they were caught at size smaller than their maturity size. The proportion of immature C. brevipinna, C. falciformis, C. sorrah and S. lewini to their total number recorded at the surveyed area during the study were about 87%, 50%, 80% and 65%, respectively. According to the length at maturity, females generally attained their maturity in larger size than males. Some factors contributing the catches in immature size and conservation status of those four species were also discussed.

Age and growth of the spinner shark Carcharhinus brevipinna (Müller and Henle, 1839) off the KwaZulu-Natal coast, South Africa

Age and growth of the spinner shark Carcharhinus brevipinna off the KwaZulu-Natal coast of South Africa was investigated from vertebral growth ring counts of 67 specimens (54–213 cm precaudal length, PCL). Counts were made from sectioned vertebral centra by two readers. There was a statistically significant difference between the growth functions of both sexes and Von Bertalanffy growth functions were L ∞ = 196.3 cm, k = 0.146 year−1 and t 0 = −2.3 year for males; L ∞ = 232.8 cm, k = 0.1 year−1 and t 0 = −2.9 year for females. This difference was thought to be attributable to initially faster growth rate of males until maturity, after which their growth rate slowed below that of females. Number of growth rings at maturity was 8–10 for both males (150 cm PCL) and females (160 cm PCL). The oldest female and male in the sample had 17 (213 cm PCL) and 19 growth rings (192 cm PCL) respectively. Annual growth ring deposition could not be validated using marginal increment ratio analysis because of the small sam...