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Male first sex-changing species

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CS3c Red (=blackspot) seabream, Pagellus bogaraveo in the Bay of Biscay. Male first sex-changing species Distributed in the Mediterranean Sea, Straight of Gibraltar, Azores, Bay of Biscay and further North (ICES VII and VI) Longevity ~20 years. Landings in the BoB. ~5 000 t/y. ~10 000 t/y.

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slide1

CS3cRed (=blackspot) seabream, Pagellus bogaraveo in the Bay of Biscay

Male first sex-changing species

Distributed in the Mediterranean Sea, Straight of Gibraltar, Azores, Bay of Biscay and further North (ICES VII and VI)

Longevity ~20 years

landings in the bob
Landings in the BoB

~5 000t/y

~10 000t/y

>15 000t/y

Effect of fish availabilty (?)

  • Significant catch by UK during the early XXth century may suggest the stock distribution extended further North (in ICES sub-area VII and even VI)
  • Reliabilty of French reported landings before the 1950s questionable
slide4

in addition to the geographical migration scheme a depth migration was understood since the 1920s

  • early juveniles are coastal in summer
  • larger fish occur on the shelf and migrate to the slope in winter
  • species known and exploited for long
  • - available also to recreational anglers and scuba divers

Spring: occurs pelagically

Late spring- Early summer: outer shelf

summer-autumn: all the shelf even coastal

January-February by depths > 400m)

From Olivier (1928) Poissons de chalut, la dorade (Pagellus centrodontus). Revue des Travaux de l\'Office des Pêches Maritimes, I, 4, 5-32

exploitation
Exploitation
  • The bulk of French landings was from the multi-species trawl fishery in the Bay fo Biscay and Celtic sea (fishing for hake, monkfish and demersal species)
  • Some catch in pelagic trawls
  • Subject of conflicts within the industry at the time of collapse
  • In the 2000s, landings reported mainly from a small handliners fishery (now banned from EU regulation)
effects of the population collapse
Effects of the population collapse

4 euros/kg when landings were high (2005 euros)

1000 t -> 4 millions euros

  • Economy
  • Net economic loss
  • Fish community
  • Effect on other species (preys, predators, competitors) unknown.
  • Bay of Biscay fish community:
      • diverse
      • numerous piscivorous predator
      • RBS was not the dominant
  • Effect on taxonomic diversity metrix small and difficult to interpret
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