Anatomy of a shark heist

Below is a guest post by Lindsey Carr, a PhD student in my lab at UNC. Lindsey is doing her dissertation research on the dynamics of shallow subtidal communities across the Galapagos archipelago. Her post is excerpted from a report she wrote for the Galapagos National Park about the catch found on the illegal vessel.

On July 19, 2011 the Galapagos National Park seized the Fer Mary I (a long-line fishing vessel) carrying 379 shark carcasses illegally fished from the coastal waters of the Galapagos Archipelago. A comprehensive effort to quantify the catch was undertaken on July 23 by scientists, students and officials from the Galapagos National Park, the University of North Carolina at Chapel Hill, Universidad de San Francisco de Quito and the Galapagos Science Center.

A total of 379 sharks were onboard the Fer Mary I.  There were 303 bigeye thresher sharks (Alopias superciliosus, IUCN status: vulnerable), 42 silky sharks (Carcharhinus falciformis, IUCN status: near threatened), 24 blue sharks (Prionace glauca, IUCN status: near threatened), 5 smooth hammerhead sharks (Sphyma zygaena, IUNC status: vulnerable), 2 tiger sharks (Galeocerdo culvier, IUCN status: near threatened), 1 Galapagos shark (Carcharhinus galapagensis, IUCN status: near threatened), 1 short fin mako shark (Isurus oxyrhinchus, IUCN status: vulnerable), and 1 unidentified shark (missing head, tail, fins and part of body).

The state of the bodies differed markedly by species.  Of the 303 Alopias superciliosus: heads and tails were removed from 184, tails were removed from 302. All Sphyma zygaena were without the hammers.  The remaining sharks were intact.

For the most abundant shark species, Alopias superciliosus, the sex ratio was female skewed (44 males per 100 females), suggesting female bias either in fishing techniques or in population structure.  However, the second most abundant species, Carcharhinus falciformis, had a male bias (162 males per 100 females).  Females were more abundant than males in the Prionace glauca catch (85 males per 100 females).  No males were found for any of the other species.  Mean total lengths reported in the scientific literature for all species were longer than the mean total length values found aboard the Fer Mary I (Bonfil 2008, Jensen 2008).  There was almost twice the amount of female shark biomass compared to male shark biomass found aboard the boat.

Total shark biomass found onboard was 22.03 metric tons or 48,568 lbs.  

 

2 Responses to “Anatomy of a shark heist”

  1. [...] each shark, measured them, and took samples for genetic and demographic analyses. Alarmingly, they discovered that the sex ratios in this catch were significantly skewed. They report that only the silky shark [...]

  2. [...] each shark, measured them, and took samples for genetic and demographic analyses. Alarmingly, they discovered that the sex ratios in this catch were significantly skewed. They report that only the silky shark [...]

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