Blue shark (Prionace glauca)
Introduction to Blue Sharks
Welcome to the enchanting world of blue sharks, where the deep blue waters off the coast of Scotland come alive with the graceful presence of Prionace glauca. These magnificent creatures, known for their sleek appearance and vibrant blue hue, are a testament to the rich marine biodiversity that graces the Scottish seas.
Welcome to the enchanting world of blue sharks, where the deep blue waters off the coast of Scotland come alive with the graceful presence of Prionace glauca. These magnificent creatures, known for their sleek appearance and vibrant blue hue, are a testament to the rich marine biodiversity that graces the Scottish seas.
Discovering the Blue Shark (Prionace glauca)
Blue Shark is oceanic and pelagic, found from the surface to at least 1,160 m depth (Queiroz et al. 2012). Occasionally, it occurs inshore where the continental shelf is narrow. It prefers temperatures of 12-20°C and is found at greater depths in tropical waters (Last and Stevens 1994).
Blue Shark is oceanic and pelagic, found from the surface to at least 1,160 m depth (Queiroz et al. 2012). Occasionally, it occurs inshore where the continental shelf is narrow. It prefers temperatures of 12-20°C and is found at greater depths in tropical waters (Last and Stevens 1994).
The species reaches a maximum size of about 380 cm total length (TL). About 50% of males in the Atlantic are sexually mature at 218 cm TL, although some may reach maturity as small as 182 cm TL. Females are sub-adult from 173-221 cm TL and fully mature from 221 cm TL (Pratt 1979).
This placental live-bearing shark produces litters averaging ~ 35 pups (maximum recorded 135 pups) after a gestation period of nine to 12 months. At birth, the pups are 35-50 cm TL. Reproduction has been reported as seasonal in most areas, with the young often born in spring or summer (Pratt 1979, Stevens 1984, Nakano 1994) although the periods of ovulation and parturition may be extended (Strasburg 1958, Hazin et al. 1994). Ageing studies estimate longevity to be ~20 years, with males maturing at four to six and females at five to seven years (Stevens 1975, Cailliet et al. 1983, Nakano 1994). Smith et al. (1998) estimated the intrinsic rate of population increase at maximum sustainable yield (MSY) to be 0.061. The generation period (average age of mature females in an unfished population) is estimated as 10 years (Dulvy et al. 2008).
This placental live-bearing shark produces litters averaging ~ 35 pups (maximum recorded 135 pups) after a gestation period of nine to 12 months. At birth, the pups are 35-50 cm TL. Reproduction has been reported as seasonal in most areas, with the young often born in spring or summer (Pratt 1979, Stevens 1984, Nakano 1994) although the periods of ovulation and parturition may be extended (Strasburg 1958, Hazin et al. 1994). Ageing studies estimate longevity to be ~20 years, with males maturing at four to six and females at five to seven years (Stevens 1975, Cailliet et al. 1983, Nakano 1994). Smith et al. (1998) estimated the intrinsic rate of population increase at maximum sustainable yield (MSY) to be 0.061. The generation period (average age of mature females in an unfished population) is estimated as 10 years (Dulvy et al. 2008).
How the Heatmap and Histogram Help Us Understand Shark Observation
Histogram
The shark observations histogram is a powerful visual tool used to illustrate the frequency of shark sightings across different categories. By organizing observed data into bins, the histogram reveals patterns in the distribution of shark characteristics, such as size, species, or the number of sightings in a specific timeframe. It provides a concise overview of the collected data, making it easier to identify trends, outliers, or clusters of information that may be crucial for research and conservation efforts. For example, a histogram can show which species are most frequently spotted or highlight seasonal variations in shark activity.
Heatmap
The heatmap complements the histogram by providing a spatial representation of shark sightings. It visualizes the density of observations over a geographical area, with colors indicating the intensity of activity—warmer colors signify higher concentrations of sightings, while cooler tones denote sparse observations. This spatial visualization helps identify hotspots for shark activity, enabling researchers to focus their efforts on areas of ecological or conservational importance. Heatmaps also aid in understanding environmental factors influencing shark distribution, such as water temperature, depth, or proximity to certain habitats.
Together, the histogram and heatmap transform raw data into actionable insights, guiding decisions in marine biology, conservation, and policy-making.
Together, the histogram and heatmap transform raw data into actionable insights, guiding decisions in marine biology, conservation, and policy-making.
