Coastal shark community assemblages reefs to rivers florida fisheries science gas knife lamb


As animals grow and mature, their needs change. electricity quiz 4th grade Throughout their life cycle, many animals relocate into different habitats to enhance their own survival, a process known as ontogenetic habitat shifts. o gascon Many shark species aggregate by size and life stage. pass gas in spanish Smaller, younger sharks are found in “nursery” areas that have a high abundance of food resources and offer protection from predators (e.g. larger sharks). electricity receiver definition When a shark reaches sexual maturity, it often moves to another location where other like-minded (and bodied) sharks of the same species aggregate. gas stoichiometry worksheet answers These movements often correspond with changes in resource requirements for larger individuals. electricity number Multiple species often share resources, geographic areas, and prefer many of the same environmental conditions that deem a habitat suitable for use and consequently, complex communities are formed. Researching how these communities change in time and space can be a daunting task, but through the use of multiple methodologies, dynamic ecological questions can be answered for many scientific applications. static electricity definition science Thus, understanding the relationship between sharks and their environment is crucial for sustainable management and conservation of shark populations (Simpfendorfer and Heupel, 2012).

Many coastal shark species of the southeastern United States are Carcharhinids, a family of fish known as the “requiem sharks.” A characteristic feature of this group is placental viviparity, in which pregnant females provide nutrients to their pups in uterovia placental connections before live birth. As a result, newborn pups have openings in their ventral surface that are essentially equivalent to a belly button in humans. These open umbilical scars heal quickly, but the size of the remaining wound can provide birthday estimations for these animals. electricity omd Once completely closed, the presence of a healed umbilical scar is still useful for identifying an animal as a young-of-year (YOY), an important life-stage distinction.

Another useful method for assessing community interactions is known as Stable Isotope Analysis (SIA), which measures the naturally occurring ratios of heavy and light chemical elements found in animal tissue. Carbon (δ 13C) and nitrogen (δ 15N)are the most common isotopes measured. δ 13C values trace the original base source of dietary carbon of a consumer, while δ 15N values are indicative of relative trophic position (Peterson and Fry 1987, Post 2002).These ratios allow researchers to infer trophic levels, niche widths, and temporal foraging patterns, which provide deeper insight into how these communities may be competing for resources.To insure successful application of SIA, one must also consider the varying turnover time of different tissue types. Tissues that are less active in metabolic processing, such as muscle tissue, take longer for a change in diet to be reflected in a consumer’s isotopic signature (~1 year) while blood plasma provides dietary insight on a much shorter time scale (~2-3 months) (MacNeil et al. 2006; Matich et al. 2011). Comparing δ 15N values of different tissue types from the same animal reveals temporal dietary changes which are common with ontogeny, while δ 13C values indicate spatial dietary changes indicative of movements into areas of different carbon sources.

A combination of ecological factors like environmental characteristics, resource abundance and distribution, and the presence of other competing species influences nearshore habitat use by sharks (Knip et al. 2010). Considering the known ecological importance of sharks, identifying influential factors on coastal shark habitat use is imperative to understand how shark species will respond to future changes in the environment (Heithaus et al. 2008, Pan et al. 2013, Yates et al. 2015).