An assessment of the diet and trophic level of Atlantic sharpnose shark Rhizoprionodon terraenovae

2014 ◽  
Vol 86 (1) ◽  
pp. 385-391 ◽  
Author(s):  
D. M. Delorenzo ◽  
D. M. Bethea ◽  
J. K. Carlson
Keyword(s):  
Trophic Level ◽  
Rhizoprionodon Terraenovae ◽  
Atlantic Sharpnose Shark

Histology and Immunology of the Placenta in the Atlantic Sharpnose Shark, Rhizoprionodon terraenovae

Placenta ◽  
2006 ◽  
Vol 27 (11-12) ◽  
pp. 1114-1123 ◽  
Author(s):  
A.N. Haines ◽  
M.F. Flajnik ◽  
J.P. Wourms
Keyword(s):  
Rhizoprionodon Terraenovae ◽  
Atlantic Sharpnose Shark

scholarly journals Diet shifts of Rhizoprionodon terraenovae from the southern Gulf of Mexico: possible scenario by temperature changes

2020 ◽  
Vol 48 (3) ◽  
pp. 406-420
Author(s):  
Javier E. Viana-Morayta ◽  
Yassir E. Torres-Rojas ◽  
Jaime Camalich-Carpizo
Keyword(s):  
Body Size ◽  
Gulf Of Mexico ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Trophic Level ◽  
Negative Relationship ◽  
Diet Breadth ◽  
Sea Surface ◽  
Rhizoprionodon Terraenovae ◽  
Southern Gulf Of Mexico

The current study examined the stomach contents of the Atlantic sharpnose shark (Rhizoprionodon terraenovae) in the southern Gulf of Mexico during 2015 to understand the relationship between diet and changes in sea surface temperature (SST). Prey-specific index of relative importance (%PSIRI), diet breadth (Bi), trophic level (TrL), and trophic overlap (PERMANOVA) were calculated between sexes, body size, and climatic seasons (dry, rainy and winter storm). The lowest temperature recorded in the area was during February (23.9°C), and the highest was during August (29.1°C). A total of 124 stomachs were analyzed, with 54.84% containing food. The trophic spectrum was composed of 32 identified prey, with demersal fish (Haemulon plumierii; %PSIRI = 22.82) and pelagic fish (Sardinella aurita; %PSIRI = 12.83) being the most important. According to the diet breadth (Bi = 0.002), Costello's graph, and trophic level (TrL = 4.2), R. terraenovae is a specialist tertiary consumer. PERMANOVA indicated significant trophic differences between sexes (F = 32.22; P < 0.05), body size (F = 13.68; P < 0.05), and among climatic seasons (F = 23.86; P < 0.05). Spearman's correlation indicated a negative relationship between the diversity of prey consumed by R. terraenovae and sea surface temperature (r = -0.75; P < 0.05). Therefore, diet for R. terraenovae is associated with SST, allowing for the development of possible scenarios related to climatic phenomena like climate change.

Changes in biological parameters of Atlantic sharpnose shark Rhizoprionodon terraenovae in the Gulf of Mexico: evidence for density-dependent growth and maturity?

2003 ◽  
Vol 54 (3) ◽  
pp. 227 ◽  
Author(s):  
John K. Carlson ◽  
Ivy E. Baremore
Keyword(s):  
Gulf Of Mexico ◽  
Growth Parameters ◽  
Biological Data ◽  
Biological Parameters ◽  
Compensatory Response ◽  
Density Dependent ◽  
Total Length ◽  
Rhizoprionodon Terraenovae ◽  
Average Size ◽  
Atlantic Sharpnose Shark

Biological parameters of the Atlantic sharpnose shark Rhizoprionodon terraenovae in the northern Gulf of Mexico were re-examined to test for potential changes due to density dependent responses. Biological data from published studies in the Gulf of Mexico collected during the period 1979–1984 were compared with data collected during the period 1998–2001. For combined sexes, the von Bertalanffy growth parameters were L∞ = 110.8 cm total length, K = 0.39 year–1 and to = –0.86 year during 1984 and L∞ = 94.0 cm total length, K = 0.73 year–1 and to = –0.88 year during 1998–2001. Median size for males and females at maturity decreased from approximately 78.3 and 80.2�cm total length (TL), respectively, in 1979–1980 to 72.6 and 75.8 cm TL, respectively, in 1998–2001. Age at maturity for combined sexes also decreased from 2.3 years in 1979–1980 to 1.4 years in 1998–2001. Litter size was similar between periods (5.0 embryos), as was the average size of embryos close to parturition (32 cm TL; 130–150�g). Growth rates using observed mean size-at-age data were higher from 1998–2001 for early ages (0–2.5 years). The observed decrease in maturity and increased growth rate lends support to the hypothesis of a compensatory response, although it could not be fully determined whether the response was due to differences in methodology among studies, anthropogenic influences or natural causes.

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