March 20, 2011 Featured Article Read More →

Sharks in Scotland’s Marine Atlas

atlasAn atlas of Scotland’s seas – providing a visual representation of its competing uses, productivity and health – has been compiled for the first time.

It is being made freely available online so that anyone with an interest in the varied waters around Scotland’s shores can find out more. In addition, school packs have been developed, including two hard copies of the atlas for every secondary school, colourful posters and an accompanying DVD.

There is a specific section relating to the species of shark found in Scottish waters which highlights :

  • Elasmobranchs range throughout the oceans and can be found in all oceanic and coastal zones.
  • Scotland has over 30 species of sharks, skates and rays recorded in its waters of which 25 are found in coastal waters.
  • All elasmobranchs share life history characteristics which make them vulnerable to overfishing and means that once depleted, populations take a long time to recover.
  • Elasmobranchs are slow growing, late to reach maturity and typically have low fecundity, thus the number of individual fish recruited into a population on an annual basis is low.
  • The number of young produced is directly proportional to the size of the female, the larger, older fish producing more young than the smaller recently mature fish.
  • The young are often fully developed and instantly capable of self nurture but they are almost instantly at danger from being taken as bycatch as they are large enough to get caught in trawl nets and dredge gear.
  • As many elasmobranchs tend to school in sex and age related groups, trawls can often pick up large numbers of juvenile fish in a single haul before they have had a chance to reproduce. Therefore relatively few animals actually reach breeding age, and those that do only produce large enough numbers of young later in life to help rebuild a population.
  • In 2009 it became compulsory for commercial fisheries to report on elasmobranch landings by species as opposed to family.
  • Many species are also vulnerable to habitat disturbance and loss and some surface dwelling species such as the basking shark are susceptible to boat strikes and harassment.

All species of sharks and rays are on the OSPAR list of Threatened and Declining Species due to their removal as both target and non-target species.

Posted in: Shark Bites
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