Diet of the Monk Seal (Monachus monachus) in Greek Waters

Graham J. Pierce, Gema Hernandez-Milian, M. Begona Santos, Panagiotis Dendrinos, Marianna Psaradellis, Eleni Tounta, Evgenia Androukaki, Alexius Edridge

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Abstract

Stomach contents were collected from 27 monk seal carcasses between 1997 and 2008 from different areas along the Greek coast. This sample included nine animals that had been deliberately killed and five accidental deaths due to fisheries interactions. Stomachs from monk seals of both sexes, including adults and subadults, were analysed. A total of 530 prey items from at least 71 prey species was identified, with approximately 74% of prey identified at least to genus, while 2.8% could be identified only to class level (i.e., fish or cephalopods). We found 266 cephalopods (50%), 253 fish (48%), a few non-cephalopod molluscs (1.5%), and two crustaceans (0.4%). Faecal samples were also collected but contained no identifiable prey remains. Octopuses were the most important prey in terms of numbers eaten and contribution to reconstructed prey biomass. The common octopus (Octopus vulgaris) (33.9% of prey by number) was around three times as numerous in the diet as the lesser octopus (Eledone cirrhosa) (11.1%). Fish of the families Sparidae (28.1%) and, to a lesser extent, Scorpaenidae (2.3%), Congridae (2.5%), and Atherinidae (2.5%) were also frequent in the stomachs. Many of the prey species recorded are of commercial fishery importance. Exploratory multivariate analysis (redundancy analysis [RDA]) indicated weakly significant seasonal, spatial, and interannual variation in diet and also suggested a relationship between diet composition and cause of death. No trends in diet related to sex or age class were identified. Sparids occurred more frequently in animals that had been deliberately killed than those that had died due to other causes, highlighting the interactions taking place between monk seals and fishing activities.

Original languageEnglish
Pages (from-to)284-297
Number of pages14
JournalAquatic Mammals
Volume37
Issue number3
DOIs
Publication statusPublished - 2011

Keywords

  • monk seal
  • Monachus monachus
  • Greece
  • fish
  • octopus
  • sparid
  • fishing interactions
  • Northwestern Hawaiian-Islands
  • length-weight relationships
  • Aegean Sea
  • conservation area
  • Cilician Basin
  • fishes
  • Turkey
  • caught
  • feces

Cite this

Pierce, G. J., Hernandez-Milian, G., Begona Santos, M., Dendrinos, P., Psaradellis, M., Tounta, E., ... Edridge, A. (2011). Diet of the Monk Seal (Monachus monachus) in Greek Waters. Aquatic Mammals, 37(3), 284-297. https://doi.org/10.1578/AM.37.3.2011.284

Diet of the Monk Seal (Monachus monachus) in Greek Waters. / Pierce, Graham J.; Hernandez-Milian, Gema; Begona Santos, M.; Dendrinos, Panagiotis; Psaradellis, Marianna; Tounta, Eleni; Androukaki, Evgenia; Edridge, Alexius.

In: Aquatic Mammals, Vol. 37, No. 3, 2011, p. 284-297.

Research output: Contribution to journalArticle

Pierce, GJ, Hernandez-Milian, G, Begona Santos, M, Dendrinos, P, Psaradellis, M, Tounta, E, Androukaki, E & Edridge, A 2011, 'Diet of the Monk Seal (Monachus monachus) in Greek Waters', Aquatic Mammals, vol. 37, no. 3, pp. 284-297. https://doi.org/10.1578/AM.37.3.2011.284
Pierce GJ, Hernandez-Milian G, Begona Santos M, Dendrinos P, Psaradellis M, Tounta E et al. Diet of the Monk Seal (Monachus monachus) in Greek Waters. Aquatic Mammals. 2011;37(3):284-297. https://doi.org/10.1578/AM.37.3.2011.284
Pierce, Graham J. ; Hernandez-Milian, Gema ; Begona Santos, M. ; Dendrinos, Panagiotis ; Psaradellis, Marianna ; Tounta, Eleni ; Androukaki, Evgenia ; Edridge, Alexius. / Diet of the Monk Seal (Monachus monachus) in Greek Waters. In: Aquatic Mammals. 2011 ; Vol. 37, No. 3. pp. 284-297.
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abstract = "Stomach contents were collected from 27 monk seal carcasses between 1997 and 2008 from different areas along the Greek coast. This sample included nine animals that had been deliberately killed and five accidental deaths due to fisheries interactions. Stomachs from monk seals of both sexes, including adults and subadults, were analysed. A total of 530 prey items from at least 71 prey species was identified, with approximately 74{\%} of prey identified at least to genus, while 2.8{\%} could be identified only to class level (i.e., fish or cephalopods). We found 266 cephalopods (50{\%}), 253 fish (48{\%}), a few non-cephalopod molluscs (1.5{\%}), and two crustaceans (0.4{\%}). Faecal samples were also collected but contained no identifiable prey remains. Octopuses were the most important prey in terms of numbers eaten and contribution to reconstructed prey biomass. The common octopus (Octopus vulgaris) (33.9{\%} of prey by number) was around three times as numerous in the diet as the lesser octopus (Eledone cirrhosa) (11.1{\%}). Fish of the families Sparidae (28.1{\%}) and, to a lesser extent, Scorpaenidae (2.3{\%}), Congridae (2.5{\%}), and Atherinidae (2.5{\%}) were also frequent in the stomachs. Many of the prey species recorded are of commercial fishery importance. Exploratory multivariate analysis (redundancy analysis [RDA]) indicated weakly significant seasonal, spatial, and interannual variation in diet and also suggested a relationship between diet composition and cause of death. No trends in diet related to sex or age class were identified. Sparids occurred more frequently in animals that had been deliberately killed than those that had died due to other causes, highlighting the interactions taking place between monk seals and fishing activities.",
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AB - Stomach contents were collected from 27 monk seal carcasses between 1997 and 2008 from different areas along the Greek coast. This sample included nine animals that had been deliberately killed and five accidental deaths due to fisheries interactions. Stomachs from monk seals of both sexes, including adults and subadults, were analysed. A total of 530 prey items from at least 71 prey species was identified, with approximately 74% of prey identified at least to genus, while 2.8% could be identified only to class level (i.e., fish or cephalopods). We found 266 cephalopods (50%), 253 fish (48%), a few non-cephalopod molluscs (1.5%), and two crustaceans (0.4%). Faecal samples were also collected but contained no identifiable prey remains. Octopuses were the most important prey in terms of numbers eaten and contribution to reconstructed prey biomass. The common octopus (Octopus vulgaris) (33.9% of prey by number) was around three times as numerous in the diet as the lesser octopus (Eledone cirrhosa) (11.1%). Fish of the families Sparidae (28.1%) and, to a lesser extent, Scorpaenidae (2.3%), Congridae (2.5%), and Atherinidae (2.5%) were also frequent in the stomachs. Many of the prey species recorded are of commercial fishery importance. Exploratory multivariate analysis (redundancy analysis [RDA]) indicated weakly significant seasonal, spatial, and interannual variation in diet and also suggested a relationship between diet composition and cause of death. No trends in diet related to sex or age class were identified. Sparids occurred more frequently in animals that had been deliberately killed than those that had died due to other causes, highlighting the interactions taking place between monk seals and fishing activities.

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