Assessing the overlap between the diet of a coastal shark and the surrounding prey communities in a sub-tropical embayment

Gutteridge, A. N., Bennett, M. B., Huveneers, C. and Tibbetts, I. R. (2011) Assessing the overlap between the diet of a coastal shark and the surrounding prey communities in a sub-tropical embayment. Journal of Fish Biology, 78 5: 1405-1422. doi:10.1111/j.1095-8649.2011.02945.x

Author Gutteridge, A. N.
Bennett, M. B.
Huveneers, C.
Tibbetts, I. R.
Title Assessing the overlap between the diet of a coastal shark and the surrounding prey communities in a sub-tropical embayment
Journal name Journal of Fish Biology   Check publisher's open access policy
ISSN 0022-1112
Publication date 2011-05-01
Year available 2011
Sub-type Article (original research)
DOI 10.1111/j.1095-8649.2011.02945.x
Open Access Status DOI
Volume 78
Issue 5
Start page 1405
End page 1422
Total pages 18
Place of publication Oxford, U.K.
Publisher Wiley-Blackwell Publishing
Language eng
Abstract Obesity and low cognitive function are associated with multiple adverse health outcomes across the life course. They have a small phenotypic correlation (r=-0.11; high body mass index (BMI)-low cognitive function), but whether they have a shared genetic aetiology is unknown. We investigated the phenotypic and genetic correlations between the traits using data from 6815 unrelated, genotyped members of Generation Scotland, an ethnically homogeneous cohort from five sites across Scotland. Genetic correlations were estimated using the following: same-sample bivariate genome-wide complex trait analysis (GCTA)-GREML; independent samples bivariate GCTA-GREML using Generation Scotland for cognitive data and four other samples (n=20 806) for BMI; and bivariate LDSC analysis using the largest genome-wide association study (GWAS) summary data on cognitive function (n=48 462) and BMI (n=339 224) to date. The GWAS summary data were also used to create polygenic scores for the two traits, with within- and cross-trait prediction taking place in the independent Generation Scotland cohort. A large genetic correlation of -0.51 (s.e. 0.15) was observed using the same-sample GCTA-GREML approach compared with -0.10 (s.e. 0.08) from the independent-samples GCTA-GREML approach and -0.22 (s.e. 0.03) from the bivariate LDSC analysis. A genetic profile score using cognition-specific genetic variants accounts for 0.08% (P=0.020) of the variance in BMI and a genetic profile score using BMI-specific variants accounts for 0.42% (P=1.9 × 10(-7)) of the variance in cognitive function. Seven common genetic variants are significantly associated with both traits at P<5 × 10(-5), which is significantly more than expected by chance (P=0.007). All these results suggest there are shared genetic contributions to BMI and cognitive function.
Formatted abstract
An elasmobranch survey of sub-tropical Hervey Bay, Australia, captured the slit-eye shark Loxodon macrorhinus at only one of three sites sampled. The dietary composition of this small shark species was compared to the prey communities within Hervey Bay to test whether prey availability was driving this observation. Dietary analysis of prey groups revealed that teleosts dominated the diet, per cent index of relative importance, % IRI (79.5%) and per cent geometric index of importance, % GII (52.7%), with shrimp-like invertebrates and cephalopods identified as the most important invertebrate prey groups. Baited remote underwater video (BRUV) used to sample prey communities at each site, demonstrated a highly diverse and significantly different community composition among the sites. There was no significant overlap between the diet of L. macrorhinus and any of the prey communities detected by BRUVs according to one-way analysis of similarities and the simplified Morisita index. Habitat electivity analysis revealed affinity of L. macrorhinus for the site with the highest water clarity (Secchi disc depth), opposing that of three other shark species. Overall, the results suggest that the distribution of L. macrorhinus is not driven by prey availability but other factors such as water clarity, predator avoidance or a reduction in interspecies competition.
Keyword BRUV
Loxodon macrorhinus
Humpback whales
Shallow habitats
Fish assemblages
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID R01 NS017950
RF1 AG015819
R01 AG054076
R01 AG017917
R01 HL105756
R01 AG008122
P30 AG010161
U01 AG049505
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Biological Sciences Publications
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Created: Sat, 03 Sep 2011, 02:42:24 EST by Gail Walter on behalf of School of Biological Sciences