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Mako Shark (mako + shark)
Kinds of Mako Shark Selected AbstractsQuantification of red myotomal muscle volume and geometry in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis) using T1 -weighted magnetic resonance imagingJOURNAL OF MORPHOLOGY, Issue 4 2007Cameron N. Perry Abstract T1 -weighted magnetic resonance imaging (MRI) in conjunction with image and segmentation analysis (i.e., the process of digitally partitioning tissues based on specified MR image characteristics) was evaluated as a noninvasive alternative for differentiating muscle fiber types and quantifying the amounts of slow, red aerobic muscle in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis). MRI-determinations of red muscle quantity and position made for the mid-body sections of three mako sharks (73.5,110 cm fork length, FL) are in close agreement (within the 95% confidence intervals) with data obtained for the same sections by the conventional dissection method involving serial cross-sectioning and volumetric analyses, and with previously reported findings for this species. The overall distribution of salmon shark red muscle as a function of body fork length was also found to be consistent with previously acquired serial dissection data for this species; however, MR imaging revealed an anterior shift in peak red muscle cross-sectional area corresponding to an increase in body mass. Moreover, MRI facilitated visualization of the intact and anatomically correct relationship of tendon linking the red muscle and the caudal peduncle. This study thus demonstrates that MRI is effective in acquiring high-resolution three-dimensional digital data with high contrast between different fish tissue types. Relative to serial dissection, MRI allows more precise quantification of the position, volume, and other details about the types of muscle within the fish myotome, while conserving specimen structural integrity. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fisheryAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2010Gilberto Sales Abstract 1.Incidental catches by the pelagic longline fishery is a major global threat for loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles. 2.The reduction of incidental capture and post-release mortality of sea turtles in the Brazilian pelagic longline fishery, operating in the south-western Atlantic Ocean, was investigated by comparing the performance of 18/0 circle hooks with 9/0 J-type (control) hooks. Hook selectivity experiments were performed between 2004 and 2008, in a total of 26 trips, 229 sets and 145 828 hooks. The experimental design included alternating control and experimental hooks along sections of the mainline. 3.An overall decrease in capture rates for loggerhead turtles of 55% and for leatherbacks of 65% were observed when using circle hooks. In addition, deep-hooking in loggerheads decreased significantly from 25% using J-hooks to 5.8% with circle hooks, potentially increasing post-release survival. 4.Circle hooks increased catch rates of most of the main target species, including tunas (bigeye Thunnus obesus and albacore T. alalunga), and sharks (blue Prionace glauca and requiem sharks of the genus Carcharinus), with no difference in the capture rates of yellowfin tuna (T. albacares), shortfin mako shark (Isurus oxyrinchus), hammerhead sharks (Sphyrna lewini and S. zygaena), and dolphinfish or mahi mahi (Coryphaena hippurus). On the other hand, a significant decrease in the capture rate of swordfish (Xiphias gladius) was detected when using circle hooks. 5.Overall, results support the effectiveness of using circle hooks for the conservation of loggerhead and leatherback sea turtles, with positive effects on capture of most target species of the south-western Atlantic longline fishery. Copyright © 2010 John Wiley & Sons, Ltd. [source] You can swim but you can't hide: the global status and conservation of oceanic pelagic sharks and raysAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2008Nicholas K. Dulvy Abstract 1.Fishing spans all oceans and the impact on ocean predators such as sharks and rays is largely unknown. A lack of data and complicated jurisdictional issues present particular challenges for assessing and conserving high seas biodiversity. It is clear, however, that pelagic sharks and rays of the open ocean are subject to high and often unrestricted levels of mortality from bycatch and targeted fisheries for their meat and valuable fins. 2.These species exhibit a wide range of life-history characteristics, but many have relatively low productivity and consequently relatively high intrinsic vulnerability to over-exploitation. The IUCN,,,World Conservation Union Red List criteria were used to assess the global status of 21 oceanic pelagic shark and ray species. 3.Three-quarters (16) of these species are classified as Threatened or Near Threatened. Eleven species are globally threatened with higher risk of extinction: the giant devilray is Endangered, ten sharks are Vulnerable and a further five species are Near Threatened. Threat status depends on the interaction between the demographic resilience of the species and intensity of fisheries exploitation. 4.4. Most threatened species, like the shortfin mako shark, have low population increase rates and suffer high fishing mortality throughout their range. Species with a lower risk of extinction have either fast, resilient life histories (e.g. pelagic stingray) or are species with slow, less resilient life histories but subject to fisheries management (e.g. salmon shark). 5.5. Recommendations, including implementing and enforcing finning bans and catch limits, are made to guide effective conservation and management of these sharks and rays. Copyright © 2008 John Wiley & Sons, Ltd. [source] Quantification of red myotomal muscle volume and geometry in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis) using T1 -weighted magnetic resonance imagingJOURNAL OF MORPHOLOGY, Issue 4 2007Cameron N. Perry Abstract T1 -weighted magnetic resonance imaging (MRI) in conjunction with image and segmentation analysis (i.e., the process of digitally partitioning tissues based on specified MR image characteristics) was evaluated as a noninvasive alternative for differentiating muscle fiber types and quantifying the amounts of slow, red aerobic muscle in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis). MRI-determinations of red muscle quantity and position made for the mid-body sections of three mako sharks (73.5,110 cm fork length, FL) are in close agreement (within the 95% confidence intervals) with data obtained for the same sections by the conventional dissection method involving serial cross-sectioning and volumetric analyses, and with previously reported findings for this species. The overall distribution of salmon shark red muscle as a function of body fork length was also found to be consistent with previously acquired serial dissection data for this species; however, MR imaging revealed an anterior shift in peak red muscle cross-sectional area corresponding to an increase in body mass. Moreover, MRI facilitated visualization of the intact and anatomically correct relationship of tendon linking the red muscle and the caudal peduncle. This study thus demonstrates that MRI is effective in acquiring high-resolution three-dimensional digital data with high contrast between different fish tissue types. Relative to serial dissection, MRI allows more precise quantification of the position, volume, and other details about the types of muscle within the fish myotome, while conserving specimen structural integrity. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||